WorldWideScience

Sample records for ground-penetrating acoustic systems

  1. Design of an ultra-wideband ground-penetrating radar system using impulse radiating antennas

    NARCIS (Netherlands)

    Rhebergen, J.B.; Zwamborn, A.P.M.; Giri, D.V.

    1999-01-01

    At TNO-FEL, one of the research programs is to explore the use of ultra-wideband (UWB) electromagnetic fields in a bi-static ground-penetrating radar (GPR) system for the detection, location and identification of buried items of unexploded ordnance (e.g. land mines). In the present paper we describe

  2. Design of an ultra-wideband ground-penetrating radar system using impulse radiating antennas

    NARCIS (Netherlands)

    Rhebergen, J.B.; Zwamborn, A.P.M.; Giri, D.V.

    1998-01-01

    At TNO-FEL, one of the research programs is to explore the use of ultra-wideband (UWB) electromagnetic fields in a bi-static ground-penetrating radar (GPR) system for the detection, location and identification of buried items of unexploded ordnance (e.g. land mines). In the present paper we describe

  3. Accounting for Hydrologic State in Ground-Penetrating Radar Classification Systems

    Science.gov (United States)

    2014-04-22

    on ground - penetrating radar (GPR) signals, particularly those associated with landmines , and (2) investigate the potential for developing contextual... ground - penetrating radar (GPR) signals, particularly those associated with landmines , and (2) investigate the potential for developing contextual GPR...on ground - penetrating radar (GPR) signals, particularly those associated with landmines , and (2) investigate the potential for developing contextual

  4. Influence of the underlying surface on the antenna system of the ground penetrating radar

    Science.gov (United States)

    Balzovsky, E. V.; Buyanov, Yu I.; Shipilov, S. E.

    2017-08-01

    Simulation results of the antenna system of the radar of subsurface sounding intended for contactless investigation of the road condition are presented. The elements of the antenna system of ground penetrating radar with extended bandwidth made as a combination of electric and magnetic type radiators have been designed. The transmission coefficient between the elements of the antenna array determining their mutual influence has been calculated. Despite the close arrangement of the elements in the array, the level of mutual influence of the elements is not critical. The developed antenna array can be used both for excitation with short ultrawideband pulses and for frequency steering in the range of 0.8-4 GHz.

  5. Ground penetrating detection using miniaturized radar system based on solid state microwave sensor.

    Science.gov (United States)

    Yao, B M; Fu, L; Chen, X S; Lu, W; Guo, H; Gui, Y S; Hu, C-M

    2013-12-01

    We propose a solid-state-sensor-based miniaturized microwave radar technique, which allows a rapid microwave phase detection for continuous wave operation using a lock-in amplifier rather than using expensive and complicated instruments such as vector network analyzers. To demonstrate the capability of this sensor-based imaging technique, the miniaturized system has been used to detect embedded targets in sand by measuring the reflection for broadband microwaves. Using the reconstruction algorithm, the imaging of the embedded target with a diameter less than 5 cm buried in the sands with a depth of 5 cm or greater is clearly detected. Therefore, the sensor-based approach emerges as an innovative and cost-effective way for ground penetrating detection.

  6. Digital Terrestrial Video Broadcast Interference Suppression in Forward-Looking Ground Penetrating Radar Systems

    Science.gov (United States)

    Rial, F. I.; Mendez-Rial, Roi; Lawadka, Lukasz; Gonzalez-Huici, Maria A.

    2014-11-01

    In this paper we show how radio frequency interference (RFI) generated by digital video broadcasting terrestrial and digital audio broadcasting transmitters can be an important noise source for forward-looking ground penetrating radar (FLGPR) systems. Even in remote locations the average interference power sometimes exceeds ultra-wideband signals by many dB, becoming the limiting factor in the system sensitivity. The overall problem of RFI and its impact in GPR systems is briefly described and several signal processing approaches to removal of RFI are discussed. These include spectral estimation and coherent subtraction algorithms and various filter approaches which have been developed and applied by the research community in similar contexts. We evaluate the performance of these methods by simulating two different scenarios submitted to real RFI acquired with a FLGPR system developed at the Fraunhofer Institute for High Frequency Physics and Radar Techniques (FHR), (GER). The effectiveness of these algorithms in removing RFI is presented using some performance indices after suppression.

  7. Detection of 3D tree root systems using high resolution ground penetration radar

    Science.gov (United States)

    Altdorff, D.; Honds, M.; Botschek, J.; Van Der Kruk, J.

    2014-12-01

    Knowledge of root systems and its distribution are important for biomass estimation as well as for the prevention of subsurface distribution network damages. Ground penetration radar (GPR) is a promising technique that enables a non-invasive imaging of tree roots. Due to the polarisation-dependent reflection coefficients and complicated three-dimensional root structure, accurate measurements with perpendicularly polarized antennas are needed. In this study, we show GPR data from two planes and one chestnut at two locations with different soil conditions. Perpendicular 10 x 10 cm grid measurements were made with a shielded 250 MHz antenna in combination with a high precision self-tracking laser theodolite that provides geo-referenced traces with a spatial resolution of ~ 2 cm. After selecting potential root hyperbolas within the perpendicular GPR profiles, the corresponding three-dimensional coordinates were extracted and visualized in planar view to reveal any linear structure that indicates a possible tree root. The coordinates of the selected linear structures were projected back to the surface by means of the laser-theodolite to indicate the locations for groundtruthing. Additionally, we interpolated the measured data into a 3D cube where time slices confirmed the locations of linear reflection events. We validated the indicated predictions by excavation of the soil with a suction dredge. Subsequent georeferencing of the true root distribution and comparison with the selected linear events showed that the approach was able to identify the precise position of roots with a diameter between 3 and 10 cm and a depth of up to 70 cm. However, not all linear events were roots; also mouse channels were found in these depths, since they also generate GPR hyperbolas aligned in linear structures. Roots at a second location at depths of 1 to 1.20 m did not generate identifiable hyperboles, which was probably due to an increased electrical conductivity below 86 cm depth. The

  8. Fusion techniques for hybrid ground-penetrating radar: electromagnetic induction landmine detection systems

    Science.gov (United States)

    Laffin, Matt; Mohamed, Magdi A.; Etebari, Ali; Hibbard, Mark

    2010-04-01

    Hybrid ground penetrating radar (GPR) and electromagnetic induction (EMI) sensors have advanced landmine detection far beyond the capabilities of a single sensing modality. Both probability of detection (PD) and false alarm rate (FAR) are impacted by the algorithms utilized by each sensing mode and the manner in which the information is fused. Algorithm development and fusion will be discussed, with an aim at achieving a threshold probability of detection (PD) of 0.98 with a low false alarm rate (FAR) of less than 1 false alarm per 2 square meters. Stochastic evaluation of prescreeners and classifiers is presented with subdivisions determined based on mine type, metal content, and depth. Training and testing of an optimal prescreener on lanes that contain mostly low metal anti-personnel mines is presented. Several fusion operators for pre-screeners and classifiers, including confidence map multiplication, will be investigated and discussed for integration into the algorithm architecture.

  9. Preliminary design of a space system operating a ground-penetrating radar

    Science.gov (United States)

    D'Errico, Marco; Ponte, Salvatore; Grassi, Michele; Moccia, Antonio

    2005-12-01

    Ground-penetrating radars (GPR) are currently used only in ground campaigns or in few airborne installations. A feasibility analysis of a space mission operating a GPR for archaeological applications is presented in this work with emphasis on spacecraft critical aspects: antenna dimension and power required for achieving adequate depth and accuracy. Sensor parametric design is performed considering two operating altitudes (250 and 500 km) and user requirements, such as minimum skin depth, vertical and horizontal resolution. A 500-km altitude, 6 a.m.-6 p.m. sun-synchronous orbit is an adequate compromise between atmospheric drag and payload transmitted average power (12 kW) to achieve a 3-m penetration depth. The satellite bus preliminary design is then performed, with focus on critical subsystems and technologies. The payload average power requirement can be kept within feasible limits (1 kW) by using NiH2 batteries to supply the radar transmitter, and with a strong reduction of the mission duty cycle ( 40km×1100km are observed per orbit). As for the electric power subsystem, a dual-voltage strategy is adopted, with the battery charge regulator supplied at 126 V and the bus loads at 50 V. The overall average power (1.9 kW), accounting for both payload and bus needs, can be supplied by a 20m2 GaAs solar panel for a three-year lifetime. Finally, the satellite mass is kept within reasonable limits (1.6 tons) using inflatable-rigidisable structure for both the payload antenna and the solar panels.

  10. An Approach for Predicting the Shape and Size of a Buried Basic Object on Surface Ground Penetrating Radar System

    Directory of Open Access Journals (Sweden)

    Nana Rachmana Syambas

    2012-01-01

    Full Text Available Surface ground-penetrating radar (GPR is one of the radar technology that is widely used in many applications. It is nondestructive remote sensing method to detect underground buried objects. However, the output target is only hyperbolic representation. This research develops a system to identify a buried object on surface GPR based on decision tree method. GPR data of many basic objects (with circular, triangular, and rectangular cross-section are classified and extracted to generate data training model as a unique template for each type of basic object. The pattern of object under test will be known by comparing its data with the training data using a decision tree method. A simple powerful algorithm to extract feature parameters of object which is based on linear extrapolation is proposed. The result showed that tested buried basic objects can be correctly predicted and the developed system works properly.

  11. Ground-penetrating radar and differential global positioning system data collected from Long Beach Island, New Jersey, April 2015

    Science.gov (United States)

    Zaremba, Nicholas J.; Smith, Kathryn E.L.; Bishop, James M.; Smith, Christopher G.

    2016-08-04

    Scientists from the United States Geological Survey, St. Petersburg Coastal and Marine Science Center, U.S. Geological Survey Pacific Coastal and Marine Science Center, and students from the University of Hawaii at Manoa collected sediment cores, sediment surface grab samples, ground-penetrating radar (GPR) and Differential Global Positioning System (DGPS) data from within the Edwin B. Forsythe National Wildlife Refuge–Holgate Unit located on the southern end of Long Beach Island, New Jersey, in April 2015 (FAN 2015-611-FA). The study’s objective was to identify washover deposits in the stratigraphic record to aid in understanding barrier island evolution. This report is an archive of GPR and DGPS data collected from Long Beach Island in 2015. Data products, including raw GPR and processed DGPS data, elevation corrected GPR profiles, and accompanying Federal Geographic Data Committee metadata can be downloaded from the Data Downloads page.

  12. Ground penetrating radar

    CERN Document Server

    Daniels, David J

    2004-01-01

    Ground-penetrating radar has come to public attention in recent criminal investigations, but has actually been a developing and maturing remote sensing field for some time. In the light of recent expansion of the technique to a wide range of applications, the need for an up-to-date reference has become pressing. This fully revised and expanded edition of the best-selling Surface-Penetrating Radar (IEE, 1996) presents, for the non-specialist user or engineer, all the key elements of this technique, which span several disciplines including electromagnetics, geophysics and signal processing. The

  13. Raw and processed ground-penetrating radar and postprocessed differential global positioning system data collected from Assateague Island, Maryland, October 2014

    Science.gov (United States)

    Zaremba, Nicholas J.; Bernier, Julie C.; Forde, Arnell S.; Smith, Christopher G.

    2016-06-08

    Scientists from the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center acquired sediment cores, sediment surface grab samples, ground-penetrating radar (GPR) and Differential Global Positioning System (DGPS) data from Assateague Island, Maryland, in October 2014. The objectives were to identify washover deposits in the stratigraphic record to aid in understanding barrier island evolution.

  14. Thermal structure and drainage system of a small valley glacier (Tellbreen, Svalbard, investigated by ground penetrating radar

    Directory of Open Access Journals (Sweden)

    K. Bælum

    2011-03-01

    Full Text Available Proglacial icings accumulate in front of many High Arctic glaciers during the winter months, as water escapes from englacial or subglacial storage. Such icings have been interpreted as evidence for warm-based subglacial conditions, but several are now known to occur in front of cold-based glaciers. In this study, we investigate the drainage system of Tellbreen, a 3.5 km long glacier in central Spitsbergen, where a large proglacial icing develops each winter, to determine the location and geometry of storage elements. Digital elevation models (DEMs of the glacier surface and bed were constructed using maps, differential GPS and ground penetrating radar (GPR. Rates of surface lowering indicate that the glacier has a long-term mass balance of −0.6 ± 0.2 m/year. Englacial and subglacial drainage channels were mapped using GPR, showing that Tellbreen has a diverse drainage system that is capable of storing, transporting and releasing water year round. In the upper part of the glacier, drainage is mainly via supraglacial channels. These transition downglacier into shallow englacial "cut and closure" channels, formed by the incision and roof closure of supraglacial channels. Below thin ice near the terminus, these channels reach the bed and contain stored water throughout the winter months. Even though no signs of temperate ice were detected and the bed is below pressure-melting point, Tellbreen has a surface-fed, channelized subglacial drainage system, which allows significant storage and delayed discharge.

  15. Thermal structure and drainage system of a small valley glacier (Tellbreen, Svalbard, investigated by Ground Penetrating Radar

    Directory of Open Access Journals (Sweden)

    K. Bælum

    2010-10-01

    Full Text Available Proglacial icings accumulate in front of many High Arctic glaciers during the winter months, as water escapes from englacial or subglacial storage. Such icings have been interpreted as evidence for warm-based subglacial conditions, but several are now known to occur in front of cold-based glaciers. In this study, we investigate the drainage system of Tellbreen, a 3.5 km long cold-based polythermal glacier in central Spitsbergen, where a large proglacial icing develops each winter, to determine the location and geometry of storage elements. DEMs of the glacier surface and bed were constructed using maps, differential GPS and GPR. Patterns of surface lowering indicate that the glacier has a long-term mass balance of −0.6 ± 0.2 m/year. Englacial and subglacial drainage channels were mapped using Ground penetrating radar (GPR, showing that Tellbreen has a diverse drainage system that is capable of storing, transporting and releasing water year round. In the upper part of the glacier, drainage is mainly via supraglacial channels. These transition downglacier into shallow englacial "cut and closure" channels, formed by the incision and closure of supraglacial channels. Below thin ice near the terminus, these channels reach the bed and contain stored water throughout the winter months. Even though the bed is below pressure-melting point, Tellbreen has a surface-fed, channelized subglacial drainage system, which allows significant storage and delayed discharge.

  16. Rapid Detection Methods for Asphalt Pavement Thicknesses and Defects by a Vehicle-Mounted Ground Penetrating Radar (GPR) System.

    Science.gov (United States)

    Dong, Zehua; Ye, Shengbo; Gao, Yunze; Fang, Guangyou; Zhang, Xiaojuan; Xue, Zhongjun; Zhang, Tao

    2016-12-06

    The thickness estimation of the top surface layer and surface layer, as well as the detection of road defects, are of great importance to the quality conditions of asphalt pavement. Although ground penetrating radar (GPR) methods have been widely used in non-destructive detection of pavements, the thickness estimation of the thin top surface layer is still a difficult problem due to the limitations of GPR resolution and the similar permittivity of asphalt sub-layers. Besides, the detection of some road defects, including inadequate compaction and delamination at interfaces, require further practical study. In this paper, a newly-developed vehicle-mounted GPR detection system is introduced. We used a horizontal high-pass filter and a modified layer localization method to extract the underground layers. Besides, according to lab experiments and simulation analysis, we proposed theoretical methods for detecting the degree of compaction and delamination at the interface, respectively. Moreover, a field test was carried out and the estimated results showed a satisfactory accuracy of the system and methods.

  17. Rapid Detection Methods for Asphalt Pavement Thicknesses and Defects by a Vehicle-Mounted Ground Penetrating Radar (GPR System

    Directory of Open Access Journals (Sweden)

    Zehua Dong

    2016-12-01

    Full Text Available The thickness estimation of the top surface layer and surface layer, as well as the detection of road defects, are of great importance to the quality conditions of asphalt pavement. Although ground penetrating radar (GPR methods have been widely used in non-destructive detection of pavements, the thickness estimation of the thin top surface layer is still a difficult problem due to the limitations of GPR resolution and the similar permittivity of asphalt sub-layers. Besides, the detection of some road defects, including inadequate compaction and delamination at interfaces, require further practical study. In this paper, a newly-developed vehicle-mounted GPR detection system is introduced. We used a horizontal high-pass filter and a modified layer localization method to extract the underground layers. Besides, according to lab experiments and simulation analysis, we proposed theoretical methods for detecting the degree of compaction and delamination at the interface, respectively. Moreover, a field test was carried out and the estimated results showed a satisfactory accuracy of the system and methods.

  18. Localizing Ground-Penetrating Radar

    Science.gov (United States)

    2014-11-01

    ing Ground-Penetrating Radar (LGPR) uses very high frequency (VHF) radar reflections of underground features to generate base- line maps and then...Innovative ground- penetrating radar that maps underground geological features provides autonomous vehicles with real-time localization. Localizing...NOV 2014 2. REPORT TYPE 3. DATES COVERED 00-00-2014 to 00-00-2014 4. TITLE AND SUBTITLE Localizing Ground-Penetrating Radar 5a. CONTRACT NUMBER

  19. Holocene relative sea level variations at the spit system Feddet (Denmark) resolved by ground-penetrating radar and geomorphological data

    DEFF Research Database (Denmark)

    Hede, Mikkel Ulfeldt; Bendixen, Mette; Clemmensen, Lars B;

    Estimates of Holocene sea-level variations have been presented in a range of studies based on different approaches, including interpretation of internal beach ridge characteristics from ground-penetrating radar (GPR) and geomorphological data. We present GPR data and geomorphological observations...... of sea level variation and vertical land movement in southern Scandinavia in response to unloading after the last glaciation. We have tested the validity of downlap points, which marks the transition from beach to upper shoreface as sea-level markers. The test is based on comparative analyses...

  20. Health monitoring of an ancient tree using ground penetrating radar - investigation of the tree root system and soil interaction

    Science.gov (United States)

    Alani, Amir M.; Bianchini Ciampoli, Luca; Tosti, Fabio; Giulia Brancadoro, Maria; Pirrone, Daniele; Benedetto, Andrea

    2017-04-01

    The sensibility towards environmental issues along with the attention on preserving natural heritage, especially ancient trees and rare plants, has greatly increased, and the management and the control of the forestall heritage and the floral system has become accordingly a high-priority objective to achieve. One of the main factors of tree decay which originally gained public attention is the presence of unknown pathogens carried along by the wind, which can lead to epidemic phenomena and often to a quick death of entire forests. In such an emergency situation, two main approaches can be followed, namely, i) active measures (i.e., the avoidance of any contact between the pathogenic spores and the trees by using bio-security measures) and ii) passive measures (i.e., the application of policies for the control and the management of the forestall heritage aimed at identifying the early-stage symptoms of the disease). Since the latest approach is based on the monitoring of living trees, invasive methods of health assessment like cutting off branches or incremental coring are increasingly discouraged, and non-destructive evaluation proves to be the only option to undertake. The applications of non-destructive testing (NDT) techniques in forestry sciences are often self-standing and not integrated with one another. This is often due to a lack of knowledge from the NDT users towards the physics and the bio-chemical processes which mainly govern the life cycle of trees and plants. Such an issue is emphasized by the evident complexity of the plant and trunk systems themselves. Notwithstanding this, the ground-penetrating radar (GPR) technique has proved to be one of the most effective, due to its high versatility, rapidity in collecting data and the provision of reliable results at relatively limited costs. The use of GPR can provide invaluable information about the effective tree trunk assessment and appraisals, tree roots mapping, soil interaction with tree and plants

  1. Ground penetrating radar for asparagus detection

    Science.gov (United States)

    Seyfried, Daniel; Schoebel, Joerg

    2016-03-01

    Ground penetrating radar is a promising technique for detection of buried objects. Recently, radar has more and more been identified to provide benefits for a plurality of applications, where it can increase efficiency of operation. One of these fields is the industrial automatic harvesting process of asparagus, which is performed so far by cutting the soil ridge at a certain height including all the asparagus spears and subsequently sieving the latter out of the soil. However, the height where the soil is cut is a critical parameter, since a wrong value leads to either damage of the roots of the asparagus plants or to a reduced crop yield as a consequence of too much biomass remaining in the soil. In this paper we present a new approach which utilizes ground penetrating radar for non-invasive sensing in order to obtain information on the optimal height for cutting the soil. Hence, asparagus spears of maximal length can be obtained, while keeping the roots at the same time undamaged. We describe our radar system as well as the subsequent digital signal processing steps utilized for extracting the information required from the recorded radar data, which then can be fed into some harvesting unit for setting up the optimal cutting height.

  2. Ground penetrating radar evaluation of the internal structure of fluvial tufa deposits (Dévanos-Añavieja system, NE Spain): an approach to different scales of heterogeneity

    Science.gov (United States)

    Pueyo Anchuela, Ó.; Luzón, A.; Pérez, A.; Muñoz, A.; Mayayo, M. J.; Gil Garbi, H.

    2016-07-01

    The Quaternary Añavieja-Dévanos tufa system is located in the northern sector of the Iberian Chain. It has been previously tackled by means sedimentological studies focused on the available outcrops and some boreholes. They have permitted the proposal of a sedimentary scenario that fits with a pool-barrage fluvial tufa model. However a better knowledge of the characteristics and internal distribution of the usually non-outcropping pool deposits as well as of its relationship with barrage deposits has not been evaluated in detail yet. Palaeoenvironmental studies on tufas are usually biased because tufas are commonly delicate facies exposed to intense erosion during water level fall stages; for this reason outcrops are usually scarce and very often coincide with the most cemented barrage deposits. In order to analyse the internal characteristics of the tufa deposits under study, but also the lateral correlation among different facies, ground penetrating radar (GPR) has been employed both for the evaluation of its applicability in such kind of environments and to improve, if possible, the sedimentary model using geophysical data in sectors without outcrops. A GPR survey including different antennas ranging from 50 to 500 MHz along different sectors and its comparison with natural outcrops has been carried out. GPR results have permitted to deduce clear differences between pool and barrage deposits and to recognise its internal structure and geometrical relationships. The survey also permitted an approach to different scales of heterogeneities in the radarfacies evaluation by using distinct antennas and therefore, reaching different resolutions and penetrations. The resulting integration from different antennas allows three different attenuant and eight reflective radarfacies to be defined permitting a better approach to the real extension of the pool areas. These results have permitted to decipher the horizontal and vertical facies changes and the identification of

  3. Adaptive Ground Penetrating Radar Systems to Visualize Antipersonnel Plastic Landmines Based on Local Texture in Scattering / Reflection Data in Space and Frequency Domains

    OpenAIRE

    Nakano, Yukimasa; Hirose, Akira

    2010-01-01

    In this chapter, first we explained the ground-penetrating radars (GPRs) which are studied currently as a new technology for the antipersonnel plastic landmine detection. In this field, researchers usually choose a measurement type from the pulse GPR or the stepped frequency GPR. Though both of these methods have merits and demerits, a steppedfrequency GPR has an advantage in the high ability to extract features over a pulse GPR.

  4. 3D Ground Penetrating Imaging Radar

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    GPiR (ground-penetrating imaging radar) is a new technology for mapping the shallow subsurface, including society’s underground infrastructure. Applications for this technology include efficient and precise mapping of buried utilities on a large scale.

  5. Identifying structural damage with ground penetrating radar

    CSIR Research Space (South Africa)

    Van Schoor, Abraham M

    2008-07-01

    Full Text Available Ground penetrating radar (GPR) and electrical resistance tomography (ERT) surveys were conducted in an urban environment in an attempt to identify the cause of severe structural damage to a historically significant residential property...

  6. Airborne ground penetrating radar: practical field experiments

    CSIR Research Space (South Africa)

    Van Schoor, Michael

    2013-10-01

    Full Text Available The performance of ground penetrating radar (GPR) under conditions where the ground coupling of the antenna is potentially compromised is investigated. Of particular interest is the effect of increasing the distance between the antennae...

  7. Planar Near-Field Measurements of Ground Penetrating Radar Antennas

    DEFF Research Database (Denmark)

    Meincke, Peter; Hansen, Thorkild

    2004-01-01

    Planar near-field measurements are formulated for a general ground penetrating radar (GPR) antenna. A total plane-wave scattering matrix is defined for the system consisting of the GPR antenna and the planar air-soil interface. The transmitting spectrum of the GPR antenna is expressed in terms...

  8. Subsurface investigation with ground penetrating radar

    Science.gov (United States)

    Ground penetrating radar (GPR) data was collected on a small test plot at the OTF/OSU Turfgrass Research & Education Facility in Columbus, Ohio. This test plot was built to USGA standards for a golf course green, with a constructed sand layer just beneath the surface overlying a gravel layer, that i...

  9. Tree root mapping with ground penetrating radar

    CSIR Research Space (South Africa)

    Van Schoor, Abraham M

    2009-09-01

    Full Text Available roots is required a detailed 3D survey approach is recommended. REFERENCES Butnor, J.R., Doolittle, J.A., Johnsen, K.H., Samuelson, L., Stokes, T. and Kress, L., 2003, Utility of Ground-Penetrating Radar as a Root Biomass Survey Tool in Forest...

  10. Ground Penetrating Radar Technologies in Ukraine

    Science.gov (United States)

    Pochanin, Gennadiy P.; Masalov, Sergey A.

    2014-05-01

    Transient electromagnetic fields are of great interest in Ukraine. The following topics are studied by research teams, with high-level achievements all over the world: (i) Ultra-Wide Band/Short-pulse radar techniques (IRE and LLC "Transient Technologies", for more information please visit http://applied.ire.kharkov.ua/radar%20systems_their%20components%20and%20relevant%20technologies_e.html and http://viy.ua); (ii) Ground Penetrating Radar (GPR) with stepped frequency sounding signals (IRE); (iii) Continuous-Wave (CW) radar with phase-shift keying signals (IRE); and (iv) Radio-wave interference investigation (Scientific and Technical Centre of The Subsurface Investigation, http://geophysics.ua). GPR applications are mainly in search works, for example GPR is often used to search for treasures. It is also used to identify leaks and diffusion of petroleum in soil, in storage areas, as well as for fault location of pipelines. Furthermore, GPR is used for the localization of underground utilities and for diagnostics of the technical state of hydro dams. Deeper GPR probing was performed to identify landslides in Crimea. Rescue radar with CW signal was designed in IRE to search for living people trapped under the rubble of collapsed buildings. The fourth version of this radar has been recently created, showing higher stability and noise immunity. Radio-wave interference investigation allows studying the soil down to tens of meters. It is possible to identify areas with increased conductivity (moisture) of the soil. LLC "Transient Technologies" is currently working with Shevchenko Kyiv University on a cooperation program in which the construction of a test site is one of the planned tasks. In the framework of this program, a GPR with a 300 MHz antenna was handed to the geological Faculty of the University. Employees of "Transient Technologies" held introductory lectures with a practical demonstration for students majoring in geophysics. The authors participated to GPR

  11. Multi-band sensor-fused explosive hazards detection in forward-looking ground penetrating radar

    Science.gov (United States)

    Havens, Timothy C.; Becker, John; Pinar, Anthony; Schulz, Timothy J.

    2014-05-01

    Explosive hazard detection and remediation is a pertinent area of interest for the U.S. Army. There are many types of detection methods that the Army has or is currently investigating, including ground-penetrating radar, thermal and visible spectrum cameras, acoustic arrays, laser vibrometers, etc. Since standoff range is an important characteristic for sensor performance, forward-looking ground-penetrating radar has been investigated for some time. Recently, the Army has begun testing a forward-looking system that combines L-band and X-band radar arrays. Our work focuses on developing imaging and detection methods for this sensor-fused system. In this paper, we investigate approaches that fuse L-band radar and X-band radar for explosive hazard detection and false alarm rejection. We use multiple kernel learning with support vector machines as the classification method and histogram of gradients (HOG) and local statistics as the main feature descriptors. We also perform preliminary testing on a context aware approach for detection. Results on government furnished data show that our false alarm rejection method improves area-under-ROC by up to 158%.

  12. Advanced Signal Analysis for Forensic Applications of Ground Penetrating Radar

    Energy Technology Data Exchange (ETDEWEB)

    Steven Koppenjan; Matthew Streeton; Hua Lee; Michael Lee; Sashi Ono

    2004-06-01

    Ground penetrating radar (GPR) systems have traditionally been used to image subsurface objects. The main focus of this paper is to evaluate an advanced signal analysis technique. Instead of compiling spatial data for the analysis, this technique conducts object recognition procedures based on spectral statistics. The identification feature of an object type is formed from the training vectors by a singular-value decomposition procedure. To illustrate its capability, this procedure is applied to experimental data and compared to the performance of the neural-network approach.

  13. Planar Near-Field Measurements of Ground Penetrating Radar Antennas

    DEFF Research Database (Denmark)

    Meincke, Peter; Hansen, Thorkild

    2004-01-01

    Planar near-field measurements are formulated for a general ground penetrating radar (GPR) antenna. A total plane-wave scattering matrix is defined for the system consisting of the GPR antenna and the planar air-soil interface. The transmitting spectrum of the GPR antenna is expressed in terms...... of measurements obtained with a buried probe as the GPR antenna moves over a scan plane on the ground. A numerical example in which the scan plane is finite validates the expressions for the spectrum of the GPR antenna....

  14. Civil engineering applications of ground penetrating radar

    CERN Document Server

    Pajewski, Lara

    2015-01-01

    This book, based on Transport and Urban Development COST Action TU1208, presents the most advanced applications of ground penetrating radar (GPR) in a civil engineering context, with documentation of instrumentation, methods, and results. It explains clearly how GPR can be employed for the surveying of critical transport infrastructure, such as roads, pavements, bridges, and tunnels, and for the sensing and mapping of underground utilities and voids. Detailed attention is also devoted to use of GPR in the inspection of geological structures and of construction materials and structures, including reinforced concrete, steel reinforcing bars, and pre/post-tensioned stressing ducts. Advanced methods for solution of electromagnetic scattering problems and new data processing techniques are also presented. Readers will come to appreciate that GPR is a safe, advanced, nondestructive, and noninvasive imaging technique that can be effectively used for the inspection of composite structures and the performance of diagn...

  15. Truffes Detection Using Ground Penetration Radar

    Directory of Open Access Journals (Sweden)

    Ali Aydın

    2015-12-01

    Full Text Available Honaz Mountain (Denizli-SW Turkey has a mild and humid climate and it produces a rich flora in the area. As a natural consequence thereof, the study area offers a rich mushroom potential that is a rising economic value. In recent years, Ground Penetration Radar (GPR is a relatively modern and effective and widely utilized technique for shallow subsurface exploration. GPR with 250 Hz antenna was employed to trace the tubers in Honaz Mountain area. To elucidate how the mushroom can reflect the signals, mineral composition of the mushrooms has been analysed. Percentage of K, Na, Ca, Mg, Fe, Al, P, S, Si, Cl minerals were significantly different from that of earth. This difference in element composition seems to cause the reflection of the signals. A large number of mushroom grooving areas have been detected during the study. The observed GPR data have been confirmed by the physical excavation. The study proposes that this method can be effectively employed to detect the natural mushrooms in the ground.

  16. Ground penetrating radar for underground sensing in agriculture: a review

    Science.gov (United States)

    Liu, Xiuwei; Dong, Xuejun; Leskovar, Daniel I.

    2016-10-01

    Belowground properties strongly affect agricultural productivity. Traditional methods for quantifying belowground properties are destructive, labor-intensive and pointbased. Ground penetrating radar can provide non-invasive, areal, and repeatable underground measurements. This article reviews the application of ground penetrating radar for soil and root measurements and discusses potential approaches to overcome challenges facing ground penetrating radar-based sensing in agriculture, especially for soil physical characteristics and crop root measurements. Though advanced data-analysis has been developed for ground penetrating radar-based sensing of soil moisture and soil clay content in civil engineering and geosciences, it has not been used widely in agricultural research. Also, past studies using ground penetrating radar in root research have been focused mainly on coarse root measurement. Currently, it is difficult to measure individual crop roots directly using ground penetrating radar, but it is possible to sense root cohorts within a soil volume grid as a functional constituent modifying bulk soil dielectric permittivity. Alternatively, ground penetrating radarbased sensing of soil water content, soil nutrition and texture can be utilized to inversely estimate root development by coupling soil water flow modeling with the seasonality of plant root growth patterns. Further benefits of ground penetrating radar applications in agriculture rely on the knowledge, discovery, and integration among differing disciplines adapted to research in agricultural management.

  17. A synthetic aperture acoustic prototype system

    Science.gov (United States)

    Luke, Robert H.; Bishop, Steven S.; Chan, Aaron M.; Gugino, Peter M.; Donzelli, Thomas P.; Soumekh, Mehrdad

    2015-05-01

    A novel quasi-monostatic system operating in a side-scan synthetic aperture acoustic (SAA) imaging mode is presented. This research project's objectives are to explore the military utility of outdoor continuous sound imaging of roadside foliage and target detection. The acoustic imaging method has several military relevant advantages such as being immune to RF jamming, superior spatial resolution as compared to 0.8-2.4 GHz ground penetrating radar (GPR), capable of standoff side and forward-looking scanning, and relatively low cost, weight and size when compared to GPR technologies. The prototype system's broadband 2-17 kHz LFM chirp transceiver is mounted on a manned all-terrain vehicle. Targets are positioned within the acoustic main beam at slant ranges of two to seven meters and on surfaces such as dirt, grass, gravel and weathered asphalt and with an intervening metallic chain link fence. Acoustic image reconstructions and signature plots result in means for literal interpretation and quantifiable analyses.

  18. Efficient Calculation of Born Scattering for Fixed-Offset Ground-Penetrating Radar Surveys

    DEFF Research Database (Denmark)

    Meincke, Peter

    2007-01-01

    A formulation is presented for efficient calculation of linear electromagnetic scattering by buried penetrable objects, as involved in the analysis of fixed-offset ground-penetrating radar (GPR) systems. The actual radiation patterns of the GPR antennas are incorporated in the scattering calculat......A formulation is presented for efficient calculation of linear electromagnetic scattering by buried penetrable objects, as involved in the analysis of fixed-offset ground-penetrating radar (GPR) systems. The actual radiation patterns of the GPR antennas are incorporated in the scattering...

  19. Numerical Modelling of Ground Penetrating Radar Antennas

    Science.gov (United States)

    Giannakis, Iraklis; Giannopoulos, Antonios; Pajewski, Lara

    2014-05-01

    Numerical methods are needed in order to solve Maxwell's equations in complicated and realistic problems. Over the years a number of numerical methods have been developed to do so. Amongst them the most popular are the finite element, finite difference implicit techniques, frequency domain solution of Helmontz equation, the method of moments, transmission line matrix method. However, the finite-difference time-domain method (FDTD) is considered to be one of the most attractive choice basically because of its simplicity, speed and accuracy. FDTD first introduced in 1966 by Kane Yee. Since then, FDTD has been established and developed to be a very rigorous and well defined numerical method for solving Maxwell's equations. The order characteristics, accuracy and limitations are rigorously and mathematically defined. This makes FDTD reliable and easy to use. Numerical modelling of Ground Penetrating Radar (GPR) is a very useful tool which can be used in order to give us insight into the scattering mechanisms and can also be used as an alternative approach to aid data interpretation. Numerical modelling has been used in a wide range of GPR applications including archeology, geophysics, forensic, landmine detection etc. In engineering, some applications of numerical modelling include the estimation of the effectiveness of GPR to detect voids in bridges, to detect metal bars in concrete, to estimate shielding effectiveness etc. The main challenges in numerical modelling of GPR for engineering applications are A) the implementation of the dielectric properties of the media (soils, concrete etc.) in a realistic way, B) the implementation of the geometry of the media (soils inhomogeneities, rough surface, vegetation, concrete features like fractures and rock fragments etc.) and C) the detailed modelling of the antenna units. The main focus of this work (which is part of the COST Action TU1208) is the accurate and realistic implementation of GPR antenna units into the FDTD

  20. The use of multi-channel ground penetrating radar and stream monitoring to investigate the seasonal evolution of englacial and subglacial drainage systems at the terminus of Exit Glacier, Alaska

    Science.gov (United States)

    Kilgore, Susan Marlena

    Concerns regarding the issue of climate change and, in particular, the rapid retreat of glaciers around the world, have placed great importance on glacial monitoring. Some of the methods most commonly used to observe glacial change---direct mass balance measurements and remote sensing---provide valuable information about glacier change. However, these methods do not address the englacial and subglacial environments. Surface meltwater that enters englacial and subglacial hydrological networks can contribute to acceleration of ice flow, increased calving on marine-terminating glaciers, surges or outburst floods, and greater overall ablation rates. Because subsurface drainage systems often freeze during the winter and re-form each summer, examining the seasonal evolution of these networks is crucial for assessing the impact that internal drainage may have on the behavior of a glacier each year. The goal of this study is to determine the role englacial and subglacial drainage system evolution plays in influencing summer ablation and discharge at the terminus of Exit Glacier, a small valley glacier located in South-central Alaska. During the summers of 2010 and 2011, we used ground-penetrating radar (GPR) to locate internal drainage features on the lower 100 meters of the glacier. GPR surveys were conducted in June and August of each year in an effort to observe the evolution of the drainage systems over the course of an ablation season. Three antenna frequencies---250, 500, and 800 MHz---were used on a dual frequency GPR so that various resolutions and depths in the ice could be viewed simultaneously. Stream monitoring was conducted to document discharge in the proglacial stream throughout the 2011 season. These data were compared with weather records to differentiate noticeable meltwater releases from precipitation events. Additionally, morphological changes in the glacier were observed through photographic documentation. Throughout the observation period, significant

  1. Ground penetrating radar antenna measurements based on plane-wave expansions

    DEFF Research Database (Denmark)

    Lenler-Eriksen, Hans-Rudolph; Meincke, Peter

    2005-01-01

    The plane-wave transmitting spectrum of the system consisting of the ground penetrating radar (GPR) antenna and the air-soil interface is measured using a loop buried in the soil. The plane-wave spectrum is used to determine various parameters characterizing the radiation of the GPR antenna...

  2. Development of ground-penetrating radar equipment for detecting pavement condition for preventive maintenance

    Science.gov (United States)

    Smith, S. S.; Scuillion, T.

    1993-10-01

    The report documents the development of a ground penetrating radar (GPR) system for locating potential maintenance problems in highway pavements. The report illustrates how GPR has the potential to detect four defects in pavements: stripping in an asphalt layer; moisture in base layer; voids or loss of support under rigid pavements; and overlay delamination.

  3. Ground penetrating radar mini-CRADA final report

    Energy Technology Data Exchange (ETDEWEB)

    Swanson, R. [AlliedSignal, Inc., Kansas City, MO (United States). Federal Mfg. and Technologies; Stump, G. [Vermeer Mfg. Co. (United States); Weil, G. [EnTech Engineering, Inc. (United States)

    1996-09-01

    The purpose of this project was to determine the feasibility of using ground penetrating radar (GPR) to assess the ease of excavability prior to and during trenching operations. The project partners were EnTech Engineering Inc., Vermeer Manufacturing Co., and AlliedSignal Federal Manufacturing & Technology (FM&T)/Kansas City Plant (KCP). Commercial GPRs were field tested as well as a system developed at AlliedSignal FM&T. The AlliedSignal GPR was centered around a HP8753 Network Analyzer instrument. Commercial GPR antennas were connected to the analyzer and data was collected under control of software written for a notebook PC. Images of sub-surface features were generated for varied system parameters including: frequency, bandwidth, FFT windowing, gain, antenna orientation, and surface roughness conditions. Depths to 10 feet were of primary interest in this project. Although further development is required, this project has demonstrated that GPR can be used to identify transitions between different sub-surface conditions, as in going from one rock type to another. Additionally, the average relative dielectric constant of the material can be estimated which can be used to help identify the material. This information can be used to characterize an excavation site for use in budgeting a job. A real-time GPR would provide the operator with sub-surface images that could help with setting the optimum feed and speed rates of the trenching machine.

  4. Efficient Underground Object Detection for Ground Penetrating Radar Signals

    Directory of Open Access Journals (Sweden)

    Ibrahim Mesecan

    2016-12-01

    Full Text Available Ground penetrating radar (GPR is one of the common sensor system for underground inspection. GPR emits electromagnetic waves which can pass through objects. The reflecting waves are recorded and digitised, and then, the B-scan images are formed. According to the properties of scanning object, GPR creates higher or lower intensity values on the object regions. Thus, these changes in signal represent the properties of scanning object. This paper proposes a 3-step method to detect and discriminate landmines: n-row average-subtraction (NRAS; Min-max normalisation; and image scaling. Proposed method has been tested using 3 common algorithms from the literature. According to the results, it has increased object detection ratio and positive object discrimination (POD significantly. For artificial neural networks (ANN, POD has increased from 77.4 per cent to 87.7 per cent. And, it has increased from 37.8 per cent to 80.2 per cent, for support vector machines (SVM.

  5. The RIMFAX Ground Penetrating Radar on the Mars 2020 Rover.

    Science.gov (United States)

    Hamran, S. E.; Amundsen, H. E. F.; Carter, L. M.; Ghent, R. R.; Kohler, J.; Mellon, M. T.; Paige, D. A.

    2014-12-01

    The Radar Imager for Mars' Subsurface Exploration - RIMFAX is a Ground Penetrating Radar selected for NASA's Mars 2020 rover mission. RIMFAX will add a new dimension to the rover's toolset by providing the capability to image the shallow subsurface beneath the rover. The principal goals of the RIMFAX investigation are to image subsurface layering and structure, and to provide information regarding subsurface composition. Depending on materials, RIMFAX will image the subsurface stratigraphy to maximum depths of 10 to 500 meters, with vertical resolutions of 5 to 20 cm, with a horizontal sampling distance of 2 to 20 cm along the rover track. The resulting radar cross sections will provide important information on the geological context of surface outcrops as well as the geological and environmental history of the field area. The radar uses a Gated FMCW waveform and a single ultra wideband antenna that is used both for transmitting and receiving. The presentation will give an overview of the RIMFAX investigation, the radar system and show experimental results from a prototype radar.

  6. VISUAL INSPECTION OF WATER LEAKAGE FROM GROUND PENETRATING RADAR RADARGRAM

    Directory of Open Access Journals (Sweden)

    N. N. Halimshah

    2015-10-01

    Full Text Available Water loss in town and suburban is currently a significant issue which reflect the performance of water supply management in Malaysia. Consequently, water supply distribution system has to be maintained in order to prevent shortage of water supply in an area. Various techniques for detecting a mains water leaks are available but mostly are time-consuming, disruptive and expensive. In this paper, the potential of Ground Penetrating Radar (GPR as a non-destructive method to correctly and efficiently detect mains water leaks has been examined. Several experiments were designed and conducted to prove that GPR can be used as tool for water leakage detection. These include instrument validation test and soil compaction test to clarify the maximum dry density (MDD of soil and simulation studies on water leakage at a test bed consisting of PVC pipe burying in sand to a depth of 40 cm. Data from GPR detection are processed using the Reflex 2D software. Identification of water leakage was visually inspected from the anomalies in the radargram based on GPR reflection coefficients. The results have ascertained the capability and effectiveness of the GPR in detecting water leakage which could help avoiding difficulties with other leak detection methods.

  7. Development of Stepped-Frequency Ground-Penetrating Radar

    DEFF Research Database (Denmark)

    Jakobsen, Kaj Bjarne

    1998-01-01

    The status of the development of a multi-monostatic stepped-frequency ground-penetrating radar (GPR) at The Department of Applied Electronics (IAE), The Technical University of Denmark (DTU) is presented. The feasibility of the used approach is demonstrated by the successful detection of small...

  8. Surface and borehole ground-penetrating-radar developments

    NARCIS (Netherlands)

    Slob, E.C.; Sato, M.; Olhoeft, G.

    2010-01-01

    During the past 80 years, ground-penetrating radar (GPR) has evolved from a skeptically received glacier sounder to a full multicomponent 3D volume-imaging and characterization device. The tool can be calibrated to allow for quantitative estimates of physical properties such as water content. Becau

  9. Development of Stepped-Frequency Ground-Penetrating Radar

    DEFF Research Database (Denmark)

    Jakobsen, Kaj Bjarne

    1998-01-01

    The status of the development of a multi-monostatic stepped-frequency ground-penetrating radar (GPR) at The Department of Applied Electronics (IAE), The Technical University of Denmark (DTU) is presented. The feasibility of the used approach is demonstrated by the successful detection of small...

  10. Ground Penetrating Radar Imaging of Buried Metallic Objects

    DEFF Research Database (Denmark)

    Polat, A. Burak; Meincke, Peter

    2001-01-01

    During the past decade there has been considerable research on ground penetrating radar (GPR) tomography for detecting objects such as pipes, cables, mines and barrels buried under the surface of the Earth. While the earlier researches were all based on the assumption of a homogeneous background...

  11. Convolutional Models for Landmine Identification with Ground Penetrating Radar

    NARCIS (Netherlands)

    Roth, F.

    2005-01-01

    This thesis presents new developments in the area of target identification with ground penetrating radar (GPR) intended for the identification of plastic and metal cased antipersonnel (AP) landmines from a single measured GPR return signal, called A-scan. The target identification is formulated as a

  12. Ground Penetrating Radar for SMART CITIES

    Science.gov (United States)

    Soldovieri, Francesco; Catapano, Ilaria; Gennarelli, Gianluca

    2016-04-01

    The use of monitoring and surveillance technologies is now recognized as a reliable option of the overall smart cities management cycle, for the advantages that they offer in terms of: economically sustainable planning of the ordinary and extraordinary maintenance interventions; situational awareness of possible risks factors in view of a reliable early warning; improvement of the security of the communities especially in public environments. In this frame, the abstract will deal with the recent advances in the development and deployment of radar systems for the urban surveillance, exploitation of the subsurface resources and civil engineering structures. In particular, we will present the recent scientific developments and several examples of use of these systems in operational conditions.

  13. Automated Ground Penetrating Radar hyperbola detection in complex environment

    Science.gov (United States)

    Mertens, Laurence; Lambot, Sébastien

    2015-04-01

    Ground Penetrating Radar (GPR) systems are commonly used in many applications to detect, amongst others, buried targets (various types of pipes, landmines, tree roots ...), which, in a cross-section, present theoretically a particular hyperbolic-shaped signature resulting from the antenna radiation pattern. Considering the large quantity of information we can acquire during a field campaign, a manual detection of these hyperbolas is barely possible, therefore we have a real need to have at our disposal a quick and automated detection of these hyperbolas. However, this task may reveal itself laborious in real field data because these hyperbolas are often ill-shaped due to the heterogeneity of the medium and to instrumentation clutter. We propose a new detection algorithm for well- and ill-shaped GPR reflection hyperbolas especially developed for complex field data. This algorithm is based on human recognition pattern to emulate human expertise to identify the hyperbolas apexes. The main principle relies in a fitting process of the GPR image edge dots detected with Canny filter to analytical hyperbolas, considering the object as a punctual disturbance with a physical constraint of the parameters. A long phase of observation of a large number of ill-shaped hyperbolas in various complex media led to the definition of smart criteria characterizing the hyperbolic shape and to the choice of accepted value ranges acceptable for an edge dot to correspond to the apex of a specific hyperbola. These values were defined to fit the ambiguity zone for the human brain and present the particularity of being functional in most heterogeneous media. Furthermore, the irregularity is particularly taken into account by defining a buffer zone around the theoretical hyperbola in which the edge dots need to be encountered to belong to this specific hyperbola. First, the method was tested in laboratory conditions over tree roots and over PVC pipes with both time- and frequency-domain radars

  14. Using ground penetrating radar for roof hazard detection in underground mines. Report of investigations/1996

    Energy Technology Data Exchange (ETDEWEB)

    Molinda, G.M.; Monaghan, W.D.; Mowrey, G.L.; Persetic, G.F.

    1996-08-01

    Ground penetrating radar (GPR) is being investigated for the potential to determine roof hazards in underground mines. GPR surveys were conducted at four field sites with accompanying ground truth in order to determine the value of GPR for roof hazard detection. The resolution of the current system allows detection of gross roof fractures (>1/4 in zone) or rider beds in coal measure roof. Differences in data quality are discussed, as well as suggestions for collecting improved data.

  15. Acoustic imaging system

    Science.gov (United States)

    Kendall, J. M., Jr.

    1977-01-01

    Tool detects noise sources by scanning sound "scene" and displaying relative location of noise-producing elements in area. System consists of ellipsoidal acoustic mirror and microphone and a display device.

  16. Detection of ground ice using ground penetrating radar method

    Institute of Scientific and Technical Information of China (English)

    Gennady M. Stoyanovich; Viktor V. Pupatenko; Yury A. Sukhobok

    2015-01-01

    The paper presents the results of a ground penetrating radar (GPR) application for the detection of ground ice. We com-bined a reflection traveltime curves analysis with a frequency spectrogram analysis. We found special anomalies at specific traces in the traveltime curves and ground boundaries analysis, and obtained a ground model for subsurface structure which allows the ground ice layer to be identified and delineated.

  17. Landmines Ground-Penetrating Radar Signal Enhancement by Digital Filtering

    OpenAIRE

    Potin, Delphine; Duflos, Emmanuel; Vanheeghe, Philippe

    2006-01-01

    Until now, humanitarian demining has been unable to provide a solution to the landmine removal problem. Furthermore, new low-cost methods have to be developed quickly. While much progress has been made with the introduction of new sensor types, other problems have been raised by these sensors. Ground-penetrating radars (GPRs) are key sensors for landmine detection as they are capable of detecting landmines with low metal contents. GPRs deliver so-called Bscan data, which are, roughly, vertica...

  18. Introduction to ground penetrating radar inverse scattering and data processing

    CERN Document Server

    Persico, Raffaele

    2014-01-01

    This book presents a comprehensive treatment of ground penetrating radar using both forward and inverse scattering mathematical techniques. Use of field data instead of laboratory data enables readers to envision real-life underground imaging; a full color insert further clarifies understanding. Along with considering the practical problem of achieving interpretable underground images, this book also features significant coverage of the problem's mathematical background. This twofold approach provides a resource that will appeal both to application oriented geologists and testing specialists,

  19. Application of Two Migration Methods for Ground Penetrating Radar Data

    Institute of Scientific and Technical Information of China (English)

    Shi Jing; Chen Shu-zhen; Zou Lian; Xiao Bo-xun

    2004-01-01

    This paper begins with the basic principles of finite-difference migration and diffraction scan migration, and then compares the processing results of the practical ground penetrating radar GPR data with these two migration methods. It is illustrated that migration can refocus the reflecting points in radar record to their true spatial location and provide the foundation for interpretation, thus improving precision of interpretation of (GPR) profiles.

  20. Application of Ground Penetrating Radar Surveys and GPS Surveys for Monitoring the Condition of Levees and Dykes

    Directory of Open Access Journals (Sweden)

    Tanajewski Dariusz

    2016-08-01

    Full Text Available This paper analyses the possibility of using integrated GPS (Global Positioning System surveys and ground penetrating radar surveys to precisely locate damages to levees, particularly due to the activity of small fossorial mammals. The technology of intercommunication between ground penetrating radar (GPR and an RTK (Real-Time Kinematic survey unit, and the method of data combination, are presented. The errors which may appear during the survey work are also characterized. The procedure for processing the data so that the final results have a spatial character and are ready to be implemented in digital maps and geographic information systems (GIS is also described.

  1. Application of Ground Penetrating Radar Surveys and GPS Surveys for Monitoring the Condition of Levees and Dykes

    Science.gov (United States)

    Tanajewski, Dariusz; Bakuła, Mieczysław

    2016-08-01

    This paper analyses the possibility of using integrated GPS (Global Positioning System) surveys and ground penetrating radar surveys to precisely locate damages to levees, particularly due to the activity of small fossorial mammals. The technology of intercommunication between ground penetrating radar (GPR) and an RTK (Real-Time Kinematic) survey unit, and the method of data combination, are presented. The errors which may appear during the survey work are also characterized. The procedure for processing the data so that the final results have a spatial character and are ready to be implemented in digital maps and geographic information systems (GIS) is also described.

  2. COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar:" ongoing research activities and mid-term results

    Science.gov (United States)

    Pajewski, Lara; Benedetto, Andrea; Loizos, Andreas; Slob, Evert; Tosti, Fabio

    2015-04-01

    This work aims at presenting the ongoing activities and mid-term results of the COST (European COoperation in Science and Technology) Action TU1208 'Civil Engineering Applications of Ground Penetrating Radar.' Almost three hundreds experts are participating to the Action, from 28 COST Countries (Austria, Belgium, Croatia, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Ireland, Italy, Latvia, Malta, Macedonia, The Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey, United Kingdom), and from Albania, Armenia, Australia, Egypt, Hong Kong, Jordan, Israel, Philippines, Russia, Rwanda, Ukraine, and United States of America. In September 2014, TU1208 has been praised among the running Actions as 'COST Success Story' ('The Cities of Tomorrow: The Challenges of Horizon 2020,' September 17-19, 2014, Torino, IT - A COST strategic workshop on the development and needs of the European cities). The principal goal of the COST Action TU1208 is to exchange and increase scientific-technical knowledge and experience of GPR techniques in civil engineering, whilst simultaneously promoting throughout Europe the effective use of this safe and non-destructive technique in the monitoring of infrastructures and structures. Moreover, the Action is oriented to the following specific objectives and expected deliverables: (i) coordinating European scientists to highlight problems, merits and limits of current GPR systems; (ii) developing innovative protocols and guidelines, which will be published in a handbook and constitute a basis for European standards, for an effective GPR application in civil- engineering tasks; safety, economic and financial criteria will be integrated within the protocols; (iii) integrating competences for the improvement and merging of electromagnetic scattering techniques and of data- processing techniques; this will lead to a novel freeware tool for the localization of buried objects

  3. Acoustic imaging system

    Science.gov (United States)

    Smith, Richard W.

    1979-01-01

    An acoustic imaging system for displaying an object viewed by a moving array of transducers as the array is pivoted about a fixed point within a given plane. A plurality of transducers are fixedly positioned and equally spaced within a laterally extending array and operatively directed to transmit and receive acoustic signals along substantially parallel transmission paths. The transducers are sequentially activated along the array to transmit and receive acoustic signals according to a preestablished sequence. Means are provided for generating output voltages for each reception of an acoustic signal, corresponding to the coordinate position of the object viewed as the array is pivoted. Receptions from each of the transducers are presented on the same display at coordinates corresponding to the actual position of the object viewed to form a plane view of the object scanned.

  4. Testing sea-level markers observed in ground-penetrating radar data from Feddet, south-eastern Denmark

    DEFF Research Database (Denmark)

    Hede, Mikkel Ulfeldt; Nielsen, Lars; Clemmensen, Lars B

    2012-01-01

    Ground-penetrating radar (GPR) data have been collected across the modern part (system on Feddet, Denmark in order to test identification of sea-level markers in GPR data from microtidal depositional environments. Nielsen and Clemmensen (2009) showed that iden......Ground-penetrating radar (GPR) data have been collected across the modern part (... that identified downlap points in GPR data from Anholt (an island in the Kattegat Sea, Denmark) can be interpreted to mark sea level at the time of deposition. The data presented here support this hypothesis. The GPR reflection data have been acquired with shielded 250 MHz Sensors & Software antennae along...

  5. Ground Penetrating Radar technique for railway track characterization in Portugal

    Science.gov (United States)

    De Chiara, Francesca; Fontul, Simona; Fortunato, Eduardo; D'Andrea, Antonio

    2013-04-01

    Maintenance actions are significant for transport infrastructures but, today, costs have to be necessary limited. A proper quality control since the construction phase is a key factor for a long life cycle and for a good economy policy. For this reason, suitable techniques have to be chosen and non-destructive tests represent an efficient solution, as they allow to evaluate infrastructure characteristics in a continuous or quasi-continuous way, saving time and costs, enabling to make changes if tests results do not comply with the project requirements. Ground Penetrating Radar (GPR) is a quick and effective technique to evaluate infrastructure condition in a continuous manner, replacing or reducing the use of traditional drilling method. GPR application to railways infrastructures, during construction and monitoring phase, is relatively recent. It is based on the measuring of layers thicknesses and detection of structural changes. It also enables the assessment of materials properties that constitute the infrastructure and the evaluation of the different types of defects such as ballast pockets, fouled ballast, poor drainage, subgrade settlement and transitions problems. These deteriorations are generally the causes of vertical deviations in track geometry and they cannot be detected by the common monitoring procedures, namely the measurements of track geometry. Moreover, the development of new GPR systems with higher antenna frequencies, better data acquisition systems, more user friendly software and new algorithms for calculation of materials properties can lead to a regular use of GPR. Therefore, it represents a reliable technique to assess track geometry problems and consequently to improve maintenance planning. In Portugal, rail inspection is performed with Plasser & Theurer EM120 equipment and recently 400 MHz IDS antennas were installed on it. GPR tests were performed on the Portuguese rail network and, as case study in this paper, a renewed track was

  6. NAPL detection with ground-penetrating radar (Invited)

    Science.gov (United States)

    Bradford, J. H.

    2013-12-01

    Non-polar organic compounds are common contaminants and are collectively referred to as nonaqueous-phase liquids (NAPLs). NAPL contamination problems occur in virtually every environment on or near the earth's surface and therefore a robust suite of geophysical tools is required to accurately characterize NAPL spills and monitor their remediation. NAPLs typically have low dielectric permittivity and low electric conductivity relative to water. Thus a zone of anomalous electrical properties often occurs when NAPL displaces water in the subsurface pore space. Such electric property anomalies make it possible to detect NAPL in the subsurface using electrical or electromagnetic geophysical methods including ground-penetrating radar (GPR). The GPR signature associated with the presence of NAPL is manifest in essentially three ways. First, the decrease in dielectric permittivity results in increased EM propagation velocity. Second, the decrease in permittivity can significantly change reflectivity. Finally, electric conductivity anomalies lead to anomalous GPR signal attenuation. The conductivity anomaly may be either high or low depending on the state of NAPL degradation, but with either high or low conductivity, GPR attenuation analysis can be a useful tool for identifying contaminated-zones. Over the past 15 years I have conducted numerous modeling, laboratory, and field tests to investigate the ability to use GPR to measure NAPL induced anomalies. The emphasis of this work has been on quantitative analysis to characterize critical source zone parameters such as NAPL concentration. Often, the contaminated zones are below the conventional resolution of the GPR signal and require thin layer analysis. Through a series of field examples, I demonstrate 5 key GPR analysis tools that can help identify and quantify NAPL contaminants. These tools include 1) GPR velocity inversion from multi-fold data, 2) amplitude vs offset analysis, 3) spectral decomposition, 4) frequency

  7. Full-wave modelling of ground-penetrating radars: antenna mutual coupling phenomena and sub-surface scattering processes

    NARCIS (Netherlands)

    Caratelli, D.; Yarovoy, A.

    2011-01-01

    Ground-penetrating radar (GPR) technology finds applications in many areas such as geophysical prospecting, archaeology, civil engineering, environmental engineering, and defence applications as a non-invasive sensing tool [3], [6], [18]. One key component in any GPR system is the receiver/transmitt

  8. Accurate Antenna Models in Ground Penetrating Radar Diffraction Tomography

    DEFF Research Database (Denmark)

    Meincke, Peter; Kim, Oleksiy S.

    2002-01-01

    Linear inversion schemes based on the concept of diffraction tomography have proven successful for ground penetrating radar (GPR) imaging. In many GPR surveys, the antennas of the GPR are located close to the air-soil interface and, therefore, it is important to incorporate the presence of this i......Linear inversion schemes based on the concept of diffraction tomography have proven successful for ground penetrating radar (GPR) imaging. In many GPR surveys, the antennas of the GPR are located close to the air-soil interface and, therefore, it is important to incorporate the presence...... of this interface in the inversion scheme (see Hansen, T.B. and Meincke Johansen, P., IEEE Trans. Geoscience and Remote Sensing, vol.38, p.496-506, 2000). Hansen and Meincke Johansen modeled the antennas as ideal (Hertzian) electric dipoles. Since practical GPR antennas are not ideal, it is of interest...... to investigate the validity of this model. We extend that formulation to hold for arbitrary antennas. For simplicity, the 2.5D case is considered, that is, it is assumed that the scattering object in the soil is invariant in one direction, which, for instance, is the case for a pipe. The arbitrary antennas...

  9. Detection of Rockfall on a Tunnel Concrete Lining with Ground-Penetrating Radar (GPR)

    Science.gov (United States)

    Lalagüe, Anne; Lebens, Matthew A.; Hoff, Inge; Grøv, Eivind

    2016-07-01

    Experiments were conducted using Ground-Penetrating Radar (GPR). The performance of six GPR systems was assessed in terms of: (1) remotely mapping cavities behind concrete linings, (2) detecting rockfall from the tunnel roof onto an inner lining comprising, for example, precast concrete segments. Studies conducted in Norway and the United States demonstrate that the GPR technique is a simple and reliable method that can assist stability inspection in existing Norwegian tunnels. The ground-coupled GPR systems represent a step forward in the remote detection of rockfall on tunnel concrete linings, and are particularly suited to self-standing inner linings. The analysis of the data is relatively straightforward and reasonably accurate.

  10. Using ground penetrating radar for roof hazard detection in underground mines

    Energy Technology Data Exchange (ETDEWEB)

    Molinda, G.M.; Monaghan, W.P.; Mowrey, G.L. [Dept. of Energy, Pittsburgh, PA (United States)

    1996-12-31

    Ground Penetrating Radar (GPR) is being investigated for the potential to determine roof hazards in underground mines. GPR surveys were conducted at four field sites with accompanying ground truth in order to determine the value of GPR for roof hazard detection. The resolution of the current system allows detection of gross roof fractures (>{1/4} in zone) or rider beds in coal measure roof. Data quality is not yet sufficient to detect small bed separations or subtle lithologic changes in the roof. Differences in data quality are discussed, as well as suggestions for collecting improved data.

  11. Using ground penetrating radar for roof hazard detection in underground mines

    Energy Technology Data Exchange (ETDEWEB)

    Molinda, G.M.; Monaghan, W.P.; Mowrey, G.L.; Persetic, G.F. [Department of Energy, Pittsburgh, PA (United States)

    1996-12-01

    Ground Penetrating Radar (GPR) is being investigated for the potential to determine roof hazards in underground mines. GPR surveys were conducted at four field sites with accompanying ground truth in order to determine the value of GPR for roof hazard detection. The resolution of the current system allows detection of gross roof fractures (>63 cm (>1/4 in) zone) or rider beds in coal measure roof. Data quality is not yet sufficient to detect small bed separations or subtle lithologic changes in the roof. Differences in data quality are discussed, as well as suggestions for collecting improved data.

  12. A review of ground penetrating radar research and practice in the United Kingdom

    Science.gov (United States)

    Giannopoulos, Antonios; Alani, Amir

    2014-05-01

    Ground penetrating radar has been playing an important role for many years in assisting in the non-destructive evaluation of UK's built environment as well as being employed in more general shallow depth geophysical investigations. Ground penetrating radar, in the United Kingdom, has a long history of original work both in developing original research ideas on fundamental aspects of the technique, both in hardware and in software, and in exploring innovative ideas relating to the practical implementation of ground penetrating radar in a number of interesting projects. For example, the base of one of the biggest organisations that connects ground penetrating radar practitioners is in the United Kingdom. This paper will endeavour to review the current status of ground penetrating radar research - primarily carried out in UK Universities - and present some key areas and work that is carried out at a practical level - primarily by private enterprises. Although, the main effort is to concentrate on ground penetrating radar applications relating to civil engineering problems other related areas of ground penetrating radar application will also be reviewed. The aim is to create a current picture of ground penetrating radar use with a view to inform and potentially enhance the possibility of new developments and collaborations that could lead to the advancement of ground penetrating radar as a geophysical investigative method. This work is a contribution to COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar.

  13. Fundamental of ground penetrating radar in environmental and engineering applications

    Directory of Open Access Journals (Sweden)

    L. Rivero

    2000-06-01

    Full Text Available Ground Penetrating Radar (GPR is a high frequency electromagnetic sounding technique that has been developed to investigate the shallow subsurface using the contrast of dielectric properties. The method operates on the simple principle that electromagnetic waves, emitted from a transmitter antenna, are reflected from buried objects and detected at another antenna, acting as receiver. GPR data is presented in the form of time-distance plots that are analogous to conventional reflection seismic records, and in fact the method has many similarities to seismic reflection method with a pulse of electromagnetic energy substituting for the elastic (seismic energy. Nevertheless, the principles and theory of the method are based on the wave equation derived from Maxwell's equations for electromagnetic wave propagation. This paper has been written for tutorial purposes, and it is hoped that it will provide the reader with a good outline of GPR presenting an overview of its theoretical basis, guidelines for interpretation and some practical field examples.

  14. Locally Adaptive Detection Algorithm for Forward-Looking Ground-Penetrating Radar

    Science.gov (United States)

    2011-02-22

    34Algorithms for landmine discrimination using the NIITEK ground penetrating radar ", Proc. SPIE 4742, 709-718 (2002). [5] Gader, P.D., Grandhi, R., Lee...W.H., Wilson, J.N., and Ho, K.C. “Feature analysis for the NIITEK ground penetrating radar using order weighted averaging operators for landmine ...34Plastic landmine detection using time-frequency analysis for forward-looking ground - penetrating radar ”, Proc. SPIE 5089, 851-862 (2003). [9] Stone

  15. Multiple Kernel Learning for Explosive Hazard Detection in Forward-Looking Ground-Penetrating Radar

    Science.gov (United States)

    2012-04-01

    34Feature analysis for the NIITEK ground penetrating radar using order weighted averaging operators for landmine detection", Proc. SPIE 5415, 953-962...This paper proposes an effective anomaly detection algorithm for forward-looking ground - penetrating radar (FLGPR). The challenges in detecting...TERMS explosive hazards detection, ground - penetrating radar , false alarm rejection, multiple kernel learning, feature-level fusion Timothy C. Havens

  16. Forward modeling of seepage of reservoir dam based on ground penetrating radar

    Directory of Open Access Journals (Sweden)

    Xueli WU

    2017-08-01

    Full Text Available The risk of the reservoir dam seepage will bring the waste of water resources and the loss of life and property. The ground penetrating radar (GPR is designed as a daily inspection system of dams to improve the existing technology which can't determine the actual situation of the dam seepage tunnel coordinates. The finite difference time domain (FDTD is used to solve the Yee's grids discreatization in two-dimensional space, and its electromagnetic distribution equation is obtained as well. Based on the actual structure of reservoir dam foundation, the ideal model of air layer, concrete layer, clay layer and two water seepage holes is described in detail, and the concrete layer interference model with limestone interference point is established. The system architecture is implemented by using MATLAB, and the forward modeling is performed. The results indicate that ground penetrating radar can be used for deep target detection. Through comparing the detection spectrum of three kinds of frequency electromagnetic wave by changing the center frequency of the GPR electromagnetic wave of 50 MHz, 100 MHz and 200 MHz, it is concluded that the scanning result is more accurate at 100 MHz. At the same time, the simulation results of the interference model show that this method can be used for the detection of complex terrain.

  17. Wireless Acoustic Measurement System

    Science.gov (United States)

    Anderson, Paul D.; Dorland, Wade D.; Jolly, Ronald L.

    2007-01-01

    A prototype wireless acoustic measurement system (WAMS) is one of two main subsystems of the Acoustic Prediction/ Measurement Tool, which comprises software, acoustic instrumentation, and electronic hardware combined to afford integrated capabilities for predicting and measuring noise emitted by rocket and jet engines. The other main subsystem is described in the article on page 8. The WAMS includes analog acoustic measurement instrumentation and analog and digital electronic circuitry combined with computer wireless local-area networking to enable (1) measurement of sound-pressure levels at multiple locations in the sound field of an engine under test and (2) recording and processing of the measurement data. At each field location, the measurements are taken by a portable unit, denoted a field station. There are ten field stations, each of which can take two channels of measurements. Each field station is equipped with two instrumentation microphones, a micro- ATX computer, a wireless network adapter, an environmental enclosure, a directional radio antenna, and a battery power supply. The environmental enclosure shields the computer from weather and from extreme acoustically induced vibrations. The power supply is based on a marine-service lead-acid storage battery that has enough capacity to support operation for as long as 10 hours. A desktop computer serves as a control server for the WAMS. The server is connected to a wireless router for communication with the field stations via a wireless local-area network that complies with wireless-network standard 802.11b of the Institute of Electrical and Electronics Engineers. The router and the wireless network adapters are controlled by use of Linux-compatible driver software. The server runs custom Linux software for synchronizing the recording of measurement data in the field stations. The software includes a module that provides an intuitive graphical user interface through which an operator at the control server

  18. Acoustic Signals and Systems

    DEFF Research Database (Denmark)

    2008-01-01

    The Handbook of Signal Processing in Acoustics will compile the techniques and applications of signal processing as they are used in the many varied areas of Acoustics. The Handbook will emphasize the interdisciplinary nature of signal processing in acoustics. Each Section of the Handbook will pr...

  19. Mapping peat morphology in sag pond with ground penetrating radar

    Science.gov (United States)

    Iryanti, Mimin; Nugraha, Harya Dwi; Setiawan, Tedy; Bijaksana, Satria

    2013-09-01

    In the tropics peat is commonly found in low-land areas. In certain condition, however, peat could also be found in high elevation, such as in sag ponds near fault zones. Information regarding thickness and morphology of peat in Sag Pond can be used to infer fault activities in the past. In this study, we attempt to identify the thickness and morphology of peat in a sag pond at Karyawangi Village near the Lembang fault, to the north of Bandung, West Java, Indonesia. We use ground penetrating radar (GPR) method with 250 Mhz antennae in several lines. The data were them processes using Reflexw software. The results show that in each survey line, peat layer is clearly identifiable. In some lines, the peat layer is continous while in some other, the peat layer is undulated. The peat layer in general in about 0.5 to 2 m thick. In conclusion, the GPR method with 250 Mhz antennae is suitable for mapping peat thickness and morphology in Sag Pond.

  20. Urban Underground Pipelines Mapping Using Ground Penetrating Radar

    Science.gov (United States)

    Jaw, S. W.; M, Hashim

    2014-02-01

    Underground spaces are now being given attention to exploit for transportation, utilities, and public usage. The underground has become a spider's web of utility networks. Mapping of underground utility pipelines has become a challenging and difficult task. As such, mapping of underground utility pipelines is a "hit-and-miss" affair, and results in many catastrophic damages, particularly in urban areas. Therefore, this study was conducted to extract locational information of the urban underground utility pipeline using trenchless measuring tool, namely ground penetrating radar (GPR). The focus of this study was to conduct underground utility pipeline mapping for retrieval of geometry properties of the pipelines, using GPR. In doing this, a series of tests were first conducted at the preferred test site and real-life experiment, followed by modeling of field-based model using Finite-Difference Time-Domain (FDTD). Results provide the locational information of underground utility pipelines associated with its mapping accuracy. Eventually, this locational information of the underground utility pipelines is beneficial to civil infrastructure management and maintenance which in the long term is time-saving and critically important for the development of metropolitan areas.

  1. Investigation of Underground Hydrocarbon Leakage using Ground Penetrating Radar

    Science.gov (United States)

    Srigutomo, Wahyu; Trimadona; Agustine, Eleonora

    2016-08-01

    Ground Penetrating Radar (GPR) survey was carried out in several petroleum plants to investigate hydrocarbon contamination beneath the surface. The hydrocarbon spills are generally recognized as Light Non-Aqueous Phase Liquids (LNAPL) if the plume of leakage is distributed in the capillary fringe above the water table and as Dense Non-Aqueous Phase Liquids (DNAPL) if it is below the water table. GPR antennas of 200 MHz and 400 MHz were deployed to obtain clear radargrams until 4 m deep. In general, the interpreted radargram sections indicate the presence of surface concrete layer, the compacted silty soill followed by sand layer and the original clayey soil as well as the water table. The presence of hydrocarbon plumes are identified as shadow zones (radar velocity and intensity contrasts) in the radargram that blur the layering pattern with different intensity of reflected signal. Based on our results, the characteristic of the shadow zones in the radargram is controlled by several factors: types of hydrocarbon (fresh or bio-degraded), water moisture in the soil, and clay content which contribute variation in electrical conductivity and dielectric constants of the soil.

  2. Stakeholder needs for ground penetrating radar utility location

    Science.gov (United States)

    Thomas, A. M.; Rogers, C. D. F.; Chapman, D. N.; Metje, N.; Castle, J.

    2009-04-01

    In the UK alone there are millions of miles of underground utilities with often inaccurate, incomplete, or non-existent location records that cause significant health and safety problems for maintenance personnel, together with the potential for large, unnecessary, social and financial costs for their upkeep and repair. This has led to increasing use of Ground Penetrating Radar (GPR) for utility location, but without detailed consideration of the degree of location accuracy required by stakeholders — i.e. all those directly involved in streetworks ranging from utility owners to contractors and surveyors and government departments. In order to ensure that stakeholder requirements are incorporated into a major new UK study, entitled Mapping the Underworld, a questionnaire has been used to determine the current and future utility location accuracy requirements. The resulting data indicate that stakeholders generally require location tolerances better than 100 mm at depths usually extending down to 3 m, and more occasionally to 5 m, below surface level, providing significant challenges to GPR if their needs are to be met in all ground conditions. As well as providing much useful data on stakeholder needs, these data are also providing a methodology for assessment of GPR utility location in terms of the factor most important to them — the degree to which the equipment provides location within their own accuracy requirements.

  3. Wavelet analysis for ground penetrating radar applications: a case study

    Science.gov (United States)

    Javadi, Mehdi; Ghasemzadeh, Hasan

    2017-10-01

    Noises may significantly disturb ground penetrating radar (GPR) signals, therefore, filtering undesired information using wavelet analysis would be challenging, despite the fact that several methods have been presented. Noises are gathered by probe, particularly from deep locations, and they may conceal reflections, suffering from small altitudes, because of signal attenuation. Multiple engineering fields need data analysis to distinguish valued material, based on information obtained by underground observations. Using wavelets as one of the useful methods for analyzing data is considered in this paper. However, optimal wavelet analysis would be challenging in the realm of exploring GPR signals. There is no doubt that accounting for wavelet function, decomposition level, threshold estimation method and threshold transformation, in the matter of de-noising and investigating signals, is of great importance; they must be chosen with judgment as they influence the results enormously if they are not carefully designated. Multiple wavelet functions are applied to perform de-noising and reconstruction on synthetic noisy signals generated by the finite-difference time-domain (FDTD) method to account for the most appropriate function for the purpose. In addition, various possible decomposition levels, threshold estimation methods and threshold transformations in the de-noising procedure are tested. The optimal wavelet analysis is also evaluated by examining real data acquired from several antenna frequencies which are common in engineering practice.

  4. On Estimation of Fracture Aperture with Ground Penetrating Radar

    Science.gov (United States)

    Linde, N.; Shakas, A.

    2016-12-01

    Ground penetrating radar (GPR) is an excellent tool for fracture imaging, but GPR-assisted estimation of fracture aperture is a largely unresolved challenge. The main reason for this is that traditional modeling techniques face severe limitations in fractured rock environments. For example, finite-difference time-domain (FDTD) formulations of Maxwell's equations are poorly adapted to deal with fractures of arbitrary orientations and apertures that are three-five orders of magnitude smaller than the modeling domain. An alternative is to use analytical solutions for thin-bed responses, but they are based on strong assumptions that often do not apply in practise. We have recently developed an efficient modeling approach to simulate GPR propagation and reflection in fractured rock. Here, we first use this modeling formulation to examine the ability of the thin-bed solution to infer the aperture of a homogeneous fracture. We then consider a suite of synthetic examples with heterogeneous fracture aperture fields of varying fractal (Hurst) exponents and spatial correlation lengths. We then use a global optimization algorithm to infer a mean (effective) fracture aperture in each case using the noise-contaminated synthetic data. The thin-bed solution leads to biased aperture estimates even if the fracture has a constant aperture and all other modeling parameters are known. With our modeling approach, we find that appropriate mean apertures are estimated in the homogeneous case, and when the correlation length of the aperture distribution is of similar scale (or larger) than the dominant GPR wavelength.

  5. Ground-penetrating radar: A tool for monitoring bridge scour

    Science.gov (United States)

    Anderson, N.L.; Ismael, A.M.; Thitimakorn, T.

    2007-01-01

    Ground-penetrating radar (GPR) data were acquired across shallow streams and/or drainage ditches at 10 bridge sites in Missouri by maneuvering the antennae across the surface of the water and riverbank from the bridge deck, manually or by boat. The acquired two-dimensional and three-dimensional data sets accurately image the channel bottom, demonstrating that the GPR tool can be used to estimate and/or monitor water depths in shallow fluvial environments. The study results demonstrate that the GPR tool is a safe and effective tool for measuring and/or monitoring scour in proximity to bridges. The technique can be used to safely monitor scour at assigned time intervals during peak flood stages, thereby enabling owners to take preventative action prior to potential failure. The GPR tool can also be used to investigate depositional and erosional patterns over time, thereby elucidating these processes on a local scale. In certain instances, in-filled scour features can also be imaged and mapped. This information may be critically important to those engaged in bridge design. GPR has advantages over other tools commonly employed for monitoring bridge scour (reflection seismic profiling, echo sounding, and electrical conductivity probing). The tool doesn't need to be coupled to the water, can be moved rapidly across (or above) the surface of a stream, and provides an accurate depth-structure model of the channel bottom and subchannel bottom sediments. The GPR profiles can be extended across emerged sand bars or onto the shore.

  6. Proximal Ignimbrite Geometry on Santorini, Greece Using Ground Penetrating Radar

    Science.gov (United States)

    Stasiuk, M. V.; Russell, J. K.; Hill, G. J.; Druitt, T. H.

    2001-12-01

    Ground penetrating radar (GPR) surveys on Santorini, Greece, are used to constrain the 3-dimensional geometry of the near-surface pyroclastic deposits produced by the 3.6 ka caldera-forming Minoan eruption. Specifically, the results elucidate deposit structures at the south end of the island. More than 2.4 km of radar survey data were collected at a measurement spacing of 0.5-1.0 m, using the common offset reflection method (3 m offset) and radar frequencies of 50 and 100 MHz. Imaging depths of the raw data were typically small (caldera rim while phase 4 gradually thickens. The GPR results suggest that the flows were more energetic than the previous model implied, and too energetic to bulk deposit in the subaerial, proximal area. Most of the mass of pyroclastics swept down the slope and into the sea, leaving behind only thin veneers. The velocity reduction caused by a combination of the phase 4 flow thickening as it passed over the ancient sea cliffs, and by entering the sea, caused the flow to switch to a strongly depositional mode resulting in a thickened deposit. An implication of these results is that most of the Minoan pyroclastic flow deposits on Santorini, apart from those near and on the outer coast, were emplaced aggradationally.

  7. Electromagnetic modelling of Ground Penetrating Radar responses to complex targets

    Science.gov (United States)

    Pajewski, Lara; Giannopoulos, Antonis

    2014-05-01

    This work deals with the electromagnetic modelling of composite structures for Ground Penetrating Radar (GPR) applications. It was developed within the Short-Term Scientific Mission ECOST-STSM-TU1208-211013-035660, funded by COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar". The Authors define a set of test concrete structures, hereinafter called cells. The size of each cell is 60 x 100 x 18 cm and the content varies with growing complexity, from a simple cell with few rebars of different diameters embedded in concrete at increasing depths, to a final cell with a quite complicated pattern, including a layer of tendons between two overlying meshes of rebars. Other cells, of intermediate complexity, contain pvc ducts (air filled or hosting rebars), steel objects commonly used in civil engineering (as a pipe, an angle bar, a box section and an u-channel), as well as void and honeycombing defects. One of the cells has a steel mesh embedded in it, overlying two rebars placed diagonally across the comers of the structure. Two cells include a couple of rebars bent into a right angle and placed on top of each other, with a square/round circle lying at the base of the concrete slab. Inspiration for some of these cells is taken from the very interesting experimental work presented in Ref. [1]. For each cell, a subset of models with growing complexity is defined, starting from a simple representation of the cell and ending with a more realistic one. In particular, the model's complexity increases from the geometrical point of view, as well as in terms of how the constitutive parameters of involved media and GPR antennas are described. Some cells can be simulated in both two and three dimensions; the concrete slab can be approximated as a finite-thickness layer having infinite extension on the transverse plane, thus neglecting how edges affect radargrams, or else its finite size can be fully taken into account. The permittivity of concrete can be

  8. FDTD analysis of ground-penetrating radar antennas with shields and absorbers

    Institute of Scientific and Technical Information of China (English)

    Liye LIU; Yi SU; Junjie MAO

    2008-01-01

    One of the most critical hardware components of a ground-penetrating radar (GPR) is the antenna system. Important parameters of antennas, such as antenna bandwidth, radiation waveform and cross coupling determine the GPR system performance. The modified TEM horn antenna with distributed resistor load is presented in this paper, and the radiation properties of the antenna with the shields and absorbers are studied through the three-dimensional finite-differ-ence time-domain (FDTD) scheme. Simulations show that the direct signal coupled from the transmitter is decreased by means of the shields and absorbers. Therefore, using the antenna in the GPR system can improve the signal-to-clutter ratio and the dynamic range of the system.

  9. COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar": first-year activities and results

    Science.gov (United States)

    Pajewski, Lara; Benedetto, Andrea; Loizos, Andreas; Slob, Evert; Tosti, Fabio

    2014-05-01

    This work aims at presenting the first-year activities and results of COST (European COoperation in Science and Technology) Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar". This Action was launched in April 2013 and will last four years. The principal aim of COST Action TU1208 is to exchange and increase scientific-technical knowledge and experience of GPR techniques in civil engineering, whilst simultaneously promoting throughout Europe the effective use of this safe and non-destructive technique in the monitoring of infrastructures and structures. Moreover, the Action is oriented to the following specific objectives and expected deliverables: (i) coordinating European scientists to highlight problems, merits and limits of current GPR systems; (ii) developing innovative protocols and guidelines, which will be published in a handbook and constitute a basis for European standards, for an effective GPR application in civil- engineering tasks; safety, economic and financial criteria will be integrated within the protocols; (iii) integrating competences for the improvement and merging of electromagnetic scattering techniques and of data- processing techniques; this will lead to a novel freeware tool for the localization of buried objects, shape-reconstruction and estimation of geophysical parameters useful for civil engineering needs; (iv) networking for the design, realization and optimization of innovative GPR equipment; (v) comparing GPR with different NDT techniques, such as ultrasonic, radiographic, liquid-penetrant, magnetic-particle, acoustic-emission and eddy-current testing; (vi) comparing GPR technology and methodology used in civil engineering with those used in other fields; (vii) promotion of a more widespread, advanced and efficient use of GPR in civil engineering; and (viii) organization of a high-level modular training program for GPR European users. Four Working Groups (WGs) carry out the research activities. The first WG

  10. Design of Wireless Automatic Synchronization for the Low-Frequency Coded Ground Penetrating Radar

    Directory of Open Access Journals (Sweden)

    Zhenghuan Xia

    2015-01-01

    Full Text Available Low-frequency coded ground penetrating radar (GPR with a pair of wire dipole antennas has some advantages for deep detection. Due to the large distance between the two antennas, the synchronization design is a major challenge of implementing the GPR system. This paper proposes a simple and stable wireless automatic synchronization method based on our developed GPR system, which does not need any synchronization chips or modules and reduces the cost of the hardware system. The transmitter omits the synchronization preamble and pseudorandom binary sequence (PRBS at an appropriate time interval, while receiver automatically estimates the synchronization time and receives the returned signal from the underground targets. All the processes are performed in a single FPGA. The performance of the proposed synchronization method is validated with experiment.

  11. Mine detection with a forward-looking ground-penetrating synthetic aperture radar

    Science.gov (United States)

    Bradley, Marshall R.; Witten, Thomas R.; Duncan, Michael; McCummins, Robert

    2003-09-01

    In order to detect buried land mines in clutter, Planning Systems Incorporated has adapted its Ground Penetrating Synthetic Aperture Radar (GPSAR) technology for forward-looking applications. The Forward Looking GPSAR (FLGPSAR), is a wide-band stepped-frequency radar operating over frequencies from 400 MHz to 4 GHz. The FLGPSAR system is based on a modified John Deere E-Gator turf vehicle that is capable of remote control. Custom Archimedean spiral antennas are used to populate the GPSAR array. These antennas are designed and built by PSI and have exceptional broad-band radiation characteristics. The FLGSPAR system has been used to detect plastic and metallic landmines at U.S. Army test facilities and at PSI's engineering center in Long Beach Mississippi. Multi-look SAR processing has been shown to significantly improve the quality of FLGPSAR imagery.

  12. Multiple instance learning for landmine detection using ground penetrating radar

    Science.gov (United States)

    Manandhar, Achut; Morton, Kenneth D., Jr.; Collins, Leslie M.; Torrione, Peter A.

    2012-06-01

    Ground Penetrating Radar (GPR) has been extensively employed as a technology for the detection of subsurface buried threats. Although vehicular mounted GPRs generate data in three dimensions, alarm declarations are usually only available in the form of 2-D spatial coordinates. The uncertainty in the depth of the target in the three dimensional volume of data, and the difficulties associated with automatically localizing objects in depth, can adversely impact feature extraction and training in some detection algorithms. In order to mitigate the negative impact of uncertainty in target depth, several algorithms have been developed that extract features from multiple depth regions and utilize these feature vectors in classification algorithms to perform final mine/nonmine decisions. However, the uncertainty in object depth significantly complicates learning since features at the correct target depth are often significantly different from features at other depths but in the same volume. Multiple Instance Learning (MIL) is a type of supervised learning approach in which labels are available for a collection of feature vectors but not for individual samples, or in this application, depths. The goal of MIL is to classify new collections of vectors as they become available. This set-based learning method is applicable in the landmine detection problem because features that are extracted independently from several depth bins can be viewed as a set of unlabeled feature vectors, where the entire set either corresponds to a buried threat or a false alarm. In this work, a novel generative Dirichlet Process Gaussian mixture model for MIL is developed that automatically infers the number of mixture components required to model the underlying distributions of mine/non-mine signatures and performs classification using a likelihood ratio test. In this work, we show that the performance of the proposed approach for discriminating targets from non-targets in GPR data is promising.

  13. Potential Enhancement of Ground Penetrating Surveys with Dispersion Properties

    Science.gov (United States)

    Tsai, C. A.; Ghent, R. R.; Boivin, A.

    2016-12-01

    Ground penetrating radar (GPR) is a nondestructive measurement technique that utilizes the transmission or reflection of electromagnetic waves to locate targets buried under Earth or artificial materials. GPR is now widely used in mining, civil engineering archaeology and hydrology. One basic premise of surface GPR is that subsurface features will return reflections which are replicas of the transmitted signal. However, phase velocities of electromagnetic waves in real materials vary with frequency. This effect becomes more noticeable in GPR frequency range with increasing moisture content. Dispersion leads to difficulty in interpreting the received signals because the reflected signals are distorted. However, the effects of dispersion on the signals may provide an opportunity to more fully characterize materials under test than is possible using traditional reflection-mode GPR techniques. In this work we present 3D-FDTD numerical modeling results using gprMax to systematically characterize the effect of dispersion on GPR signals. In addition to numerical results, we assess the feasibility of applying our results to terrestrial geophysical scenarios by measuring the dielectric permittivities of a selection of natural materials, including samples from a massive sulphide mine. Our goal is to establish a parameter space that systematically characterize the effect of each parameter in the common dispersion models (Debye, Lorentz and Drude) on GPR signals. We begin the experiment by drying the samples completely and then adding water into the samples in 5 wt % increments. We measure the broadband relative permittivity and loss tangent using a coaxial transmission line for each state from 300 kHz to 8.5 GHz. The results provide a database for future GPR signal interpretation.

  14. O' Connell bridge inspection by means of Ground Penetrating Radar

    Science.gov (United States)

    Santos Assuncao, Sonia, ,, Dr

    2016-04-01

    Ground Penetrating Radar (GPR) is a well-known technique successfully applied in different areas. In structural inspection the methodology may expose information about structural arrangement and pathologies. GPR emits high frequency electromagnetic impulses allowing to detect changes on the electromagnetic properties: electrical conductivity, dielectric constant and magnetic permeability. The central frequency of the each antenna is characterized by a specific resolution and penetration depth. Therefore, different scales of structures can be analysed. High frequency antennas output high resolution images/signals about the shallowest elements such as rebar and the thickness of the first layer. On the other hand, intermediate or lower frequency antennas locate deeper structures, such as the thickness of the arch. The compilation of distinct frequencies gives a better understanding and a more accurate detection of elements in the inner structure. O'Connell Bridge (1877) is one of 24 bridges along River Liffey and one the most famous historical structures in Dublin. It is composed by sandstones and granite and covered by asphalt which represents a suitable structure to evaluate by means of GPR. The lack of inner structural information, especially the thickness of the layer, presence of reinforcement or other metallic elements of support required, at least, a dual frequency analysis of the bridge. In this case, it was applied the (200 MHz and 600 MHz) Multi-Channel Stream EM combined with 1.6 GHz GSSI high frequency antenna. The inspection of bridges by means of GPR may provide not exclusively interesting structural data but historical information and the state of conservation.

  15. Feature Extraction and Automatic Material Classification of Underground Objects from Ground Penetrating Radar Data

    Directory of Open Access Journals (Sweden)

    Qingqing Lu

    2014-01-01

    Full Text Available Ground penetrating radar (GPR is a powerful tool for detecting objects buried underground. However, the interpretation of the acquired signals remains a challenging task since an experienced user is required to manage the entire operation. Particularly difficult is the classification of the material type of underground objects in noisy environment. This paper proposes a new feature extraction method. First, discrete wavelet transform (DWT transforms A-Scan data and approximation coefficients are extracted. Then, fractional Fourier transform (FRFT is used to transform approximation coefficients into fractional domain and we extract features. The features are supplied to the support vector machine (SVM classifiers to automatically identify underground objects material. Experiment results show that the proposed feature-based SVM system has good performances in classification accuracy compared to statistical and frequency domain feature-based SVM system in noisy environment and the classification accuracy of features proposed in this paper has little relationship with the SVM models.

  16. Acoustic Signals and Systems

    DEFF Research Database (Denmark)

    2008-01-01

    The Handbook of Signal Processing in Acoustics will compile the techniques and applications of signal processing as they are used in the many varied areas of Acoustics. The Handbook will emphasize the interdisciplinary nature of signal processing in acoustics. Each Section of the Handbook...... will present topics on signal processing which are important in a specific area of acoustics. These will be of interest to specialists in these areas because they will be presented from their technical perspective, rather than a generic engineering approach to signal processing. Non-specialists, or specialists...

  17. Finite difference time domain method forward simulation of complex geoelectricity ground penetrating radar model

    Institute of Scientific and Technical Information of China (English)

    DAI Qian-wei; FENG De-shan; HE Ji-shan

    2005-01-01

    The ground penetrating radar(GPR) forward simulation all aims at the singular and regular models, such as sandwich model, round cavity, square cavity, and so on, which are comparably simple. But as to the forward of curl interface underground or "v" figure complex model, it is difficult to realize. So it is important to forward the complex geoelectricity model. This paper takes two Maxwell's vorticity equations as departure point, makes use of the principles of Yee's space grid model theory and the basic principle finite difference time domain method, and deduces a GPR forward system of equation of two dimensional spaces. The Mur super absorbed boundary condition is adopted to solve the super strong reflection on the interceptive boundary when there is the forward simulation. And a self-made program is used to process forward simulation to two typical geoelectricity model.

  18. Tomographic airborne ground penetrating radar imaging: Achievable spatial resolution and on-field assessment

    Science.gov (United States)

    Catapano, Ilaria; Crocco, Lorenzo; Krellmann, Yvonne; Triltzsch, Gunnar; Soldovieri, Francesco

    2014-06-01

    Ground Penetrating Radar (GPR) airborne systems are gaining an increasing attention as effective monitoring tools capable of underground investigation of wide areas. With respect to this frame, the paper deals with a reconstruction approach specifically designed to image buried targets from airborne gathered scattered field data. The role of the measurement configuration is investigated in order to address the practical problem of how multi-monostatic and multi-frequency data should be gathered, in terms of synthetic aperture length and frequency range, and how the available data affect the achievable reconstruction capabilities. Such an analysis allows us to evaluate the performance of the reconstruction approach in terms of transversal and depth resolution limits. Finally, an experimental validation of the approach is performed by processing real data.

  19. Explosive hazard detection using MIMO forward-looking ground penetrating radar

    Science.gov (United States)

    Shaw, Darren; Ho, K. C.; Stone, Kevin; Keller, James M.; Popescu, Mihail; Anderson, Derek T.; Luke, Robert H.; Burns, Brian

    2015-05-01

    This paper proposes a machine learning algorithm for subsurface object detection on multiple-input-multiple-output (MIMO) forward-looking ground-penetrating radar (FLGPR). By detecting hazards using FLGPR, standoff distances of up to tens of meters can be acquired, but this is at the degradation of performance due to high false alarm rates. The proposed system utilizes an anomaly detection prescreener to identify potential object locations. Alarm locations have multiple one-dimensional (ML) spectral features, two-dimensional (2D) spectral features, and log-Gabor statistic features extracted. The ability of these features to reduce the number of false alarms and increase the probability of detection is evaluated for both co-polarizations present in the Akela MIMO array. Classification is performed by a Support Vector Machine (SVM) with lane-based cross-validation for training and testing. Class imbalance and optimized SVM kernel parameters are considered during classifier training.

  20. INVESTIGATION OF GROUND PENETRATING RADAR FOR DETECTION OF ROAD SUBSIDENCE NORTHCOAST OF JAKARTA, INDONESIA

    Directory of Open Access Journals (Sweden)

    Kris Budiono

    2017-07-01

    Full Text Available A survey of Ground Penetrating Radar (GPR was conducted in the coastal zone of northern part of Jakarta, Indonesia. The purpose of this survey was to provide the subsurface of coastal Quaternary sedimentary features and stratigraphy disturbances associated with induce post road subsidence 2009. The possibility of subsurface lithology disturbance shown by the GPR record. This record resulted from GPR methods using SIR system 20 GSSI, 270 MHz and 400 MHz and MLF 3200 transducer. The method is a promising tool for resolving changes of physical properties in subsurface lithology condition at the natural scale due to composition changes of physical properties.The reflection data resulted that GPR can distinguish between image the basic geometry forms such as lithology , structure geology , soil and subsurface utilities condition

  1. VALUATION OF GROUND PENETRATING RADAR FOR THE RECORD OF STRUCTURES IN FLUVIO LACUSTRINE SOILS

    Directory of Open Access Journals (Sweden)

    E. Méndez

    2003-04-01

    Full Text Available In this work, the response of Ground Penetrating Radar (GPR to geological characteristics of fluvio-lacustrinesoils is analyzed. GPR method is a very useful tool for structural studies of the geological media because itprovides continuous profiles from the subsoil (radargrams. The identification of thin geological structures inthe radar profiles allowed the evaluation of the detection capacity of the GPR Zond 12c for stratigraphicalpurposes. Its detection capacity depends on the achieved depth of penetration and resolution, on thetransmitted wave frequency, and of the system used for acquisition and processing of the signals. Theprospecting principle is based on the emission and reception of short electromagnetic pulses that are reflectedby electric discontinuities related to physical or structural properties of the ground.

  2. Ground penetrating radar estimates of permafrost ice wedge depth

    Science.gov (United States)

    Parsekian, A.; Slater, L. D.; Nolan, J. T.; Grosse, G.; Walter Anthony, K. M.

    2013-12-01

    Vertical ground ice wedges associated with polygonal patterning in permafrost environments form due to frost cracking of soils under harsh winter conditions and subsequent infilling of cracks with snow melt water. Ice wedge polygon patterns have implications for lowland geomorphology, hydrology, and vulnerability of permafrost to thaw. Ice wedge dimensions may exceed two meters width at the surface and several meters depth, however few studies have addressed the question of ice wedge depth due to challenges related to measuring the vertical dimension below the ground. Vertical exposures where ice wedges maybe observed are limited to rapidly retreating lake, river, and coastal bluffs. Coring though the ice wedges to determine vertical extent is possible, however that approach is time consuming and labor intensive. Many geophysical investigations have noted signal anomalies related to the presence of ice wedges, but no reliable method for extracting wedge dimensions from geophysical data has been yet proposed. Here we present new evidence that ground penetrating radar (GPR) may be a viable method for estimating ice wedge depth. We present three new perspectives on processing GPR data collected over ice wedges that show considerable promise for use as a fast, cost effective method for evaluating ice wedge depth. Our novel approaches include 1) a simple frequency-domain analysis, 2) an S-transform frequency domain analysis and 3) an analysis of the returned signal power as a radar cross section (RCS) treating subsurface ice wedges as dihedral corner retro-reflectors. Our methods are demonstrated and validated using finite-difference time domain FDTD) GPR forward models of synthetic idealized ice wedges and field data from permafrost sites in Alaska. Our results indicate that frequency domain and signal power data provide information that is easier to extract from raw GPR data than similar information in the time domain. We also show that we can simplify the problem by

  3. Analysis of landslide mitigation effects using Ground Penetrating Radar

    Science.gov (United States)

    Ristic, Aleksandar; Govedarica, Miro; Vrtunski, Milan; Petrovacki, Dusan

    2013-04-01

    Area of Ground Penetrating Radar (GPR) technology applications becomes wider nowadays. It includes utility mapping as important part of civil engineering applications, geological structure and soil analyses, applications in agriculture, etc. Characteristics of the technology make it suitable for structure analysis of shallow landslides, whose number and impact on environment is dominant in the region. Especially when shallow landslide endangers some man-made structures such as buildings, roads or bridges, analysis of GPR data can yield very useful results. The results of GPR data analysis of the shallow landslide are represented here. It is situated on the mountain Fruska Gora in Serbia. Despite its dimensions (50x20m) this landslide was interesting for analysis for two reasons: - The landslide occurred at the part of the single road between the cement factory and the marl mine. The cement factory "Lafarge" in Beocin (Fruska Gora) is the largest cement manufacturer in the country. One of major priorities of the factory management is to keep the function of this road. The road is heavily exploited and over the years it led to landslide movements and damaging of the road itself. - The landslide dates back to earlier period and the mitigation measures were performed twice. Laying the foundation of the retaining wall was not performed during the first mitigation measures. The second mitigation measures were performed in 2010 and included detailed geotechnical analysis of the location with the appropriate foundation laying. Since the GPR technology can produce high resolution images of subsurface it provides clear insight into the current state of surveyed location. That kind of analysis is necessary to maintain permanent functionality of the road and to check the status of mitigation measures. Furthermore, the location characteristics do not allow easy access so the possibilities of other analysis technologies application are limited. In order to assess the effects of

  4. Autonomous Acoustic Receiver System

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Collects underwater acoustic data and oceanographic data. Data are recorded onboard an ocean buoy and can be telemetered to a remote ship or shore station...

  5. Ground Penetrating Radar employment for searching ancient cisterns.

    Science.gov (United States)

    Semeraro, Grazia; Notario, Corrado; Persico, Raffaele

    2017-04-01

    Ground Penetrating Radar technology and methodology can provide support for the archaeological research. In particular, investigations in archaeological sites [1-3] and monuments of historical interest [4-6] have provided in many cases information of interest about the presence, the size, the shape and the depth of embedded anomalies, that can range from foundations to crypts, or also walled passages, walled doors, embedded voids or reinforcement bars, fractures and so on. In this contribution we will focus on the possibility to identify ancient cisterns with the aid of a GPR prospection. In particular, the attention will be focused on Messapic cisterns. The Messapians were a population that used to reside in the southern part of the Apulia region (the so called Salento), Their remains dates back from the 8th century B.C. up to the Roman conquest, in the 3rd century B.C. They used to build cisterns for gathering the rain water, both for drinking and for agricultural purposes. The shape of the cisterns can be quite different from case to case, and rarely they are found empty. Rether, in most cases the remains shows a structure with the roof collapsed and filled up with loose materials, which makes their identification with a GPR a challenging issue. At the conference, the results and the interpretation of GPR data gathered in the two Messapic sites of San Vito dei Normanni and Cavallino (both in the Salento area) will be shown and discussed. References 1) R. Lasaponara, G. Leucci, N. Masini, R. Persico, Investigating archaeological looting using satellite images and GEORADAR: the experience in Lambayeque in North Peru, Journal of Archaeological Science, vol. 42, pp. 216-230, 2014. 2) R. Castaldo, L. Crocco, M. Fedi, B. Garofalo, R. Persico, A. Rossi, F. Soldovieri, GPR Microwave Tomography for Diagnostic of Archaeological Sites: the Case of a high-way construction in Pontecagnano (Southern Italy), Archaeological Prospection, vol. 16, pp. 203-217, 2009. 3) L. Matera

  6. COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar": ongoing research activities and third-year results

    Science.gov (United States)

    Pajewski, Lara; Benedetto, Andrea; Loizos, Andreas; Tosti, Fabio

    2016-04-01

    buried objects, shape-reconstruction and estimation of geophysical parameters useful for civil engineering needs; (iv) networking for the design, realization and optimization of innovative GPR equipment; (v) comparing GPR with different NDT techniques, such as ultrasonic, radiographic, liquid-penetrant, magnetic-particle, acoustic-emission and eddy-current testing; (vi) comparing GPR technology and methodology used in civil engineering with those used in other fields; (vii) promotion of a more widespread, advanced and efficient use of GPR in civil engineering; and (viii) organization of a high-level modular training program for GPR European users. Four Working Groups (WGs) carry out the research activities. WG 1 focuses on the design of innovative GPR equipment, on the building of prototypes and on the testing and optimisation of new systems. WG 2 focuses on the GPR surveying of pavement, bridges, tunnels and buildings, as well as on the sensing of underground utilities and voids. WG 3 deals with the development of electromagnetic forward and inverse scattering methods, for the characterization of GPR scenarios, as well as with data-processing algorithms for the elaboration of the data collected during GPR surveys. WG 4 works on the use of GPR in fields different from the civil engineering, as well as on the integration of GPR with other non-destructive testing techniques. Each WG includes several Projects. COST Action TU1208 is active through a range of networking tools: meetings, workshops, conferences, training schools, short-term scientific missions, dissemination activities. For more information on COST Action TU1208, please visit www.GPRadar.eu and www.cost.eu. Acknowledgement The Authors wish to thank COST, for funding the COST Action TU1208 "Civil engineering applications of Ground Penetrating Radar."

  7. Joint ACE ground penetrating radar antenna test facility at the Technical University of Denmark

    DEFF Research Database (Denmark)

    Lenler-Eriksen, Hans-Rudolph; Meincke, Peter; Sarri, A.;

    2005-01-01

    A ground penetrating radar (GPR) antenna test facility, established within the ACE network at the Technical University of Denmark (DTU), is described. Examples of results from the facility obtained from measurements of eight different GPR antennas are presented.......A ground penetrating radar (GPR) antenna test facility, established within the ACE network at the Technical University of Denmark (DTU), is described. Examples of results from the facility obtained from measurements of eight different GPR antennas are presented....

  8. Ground-penetrating radar for sedimentology: methodological advances and examples from the Usumacinta-Grijalva delta plain, Tabasco, México

    NARCIS (Netherlands)

    Van Dam, Remke; Nooren, Kees; Dogan, Mine; Hoek, Wim

    2014-01-01

    Ground-penetrating radar (GPR) is widely used as a tool for imaging sedimentary structures and reconstructing depositional history in a range of settings. Most GPR systems use a pair of dipole antennas to transmit and receive electromagnetic energy, typically in the frequency range of 0.025-1 GHz. R

  9. Integrating ground-penetrating radar and borehole data from a Wadden Sea barrier island

    DEFF Research Database (Denmark)

    Nielsen, Lars; Møller, I.; Nielsen, L. H.

    2009-01-01

    Sea level rise may have large implications for low-gradient barrier coastal systems. This problem motivated an integrated ground-penetrating radar (GPR) and sedimentological study of the Rømø Wadden Sea barrier island. Crossing W-E and N-S-oriented 100 MHz GPR reflection profiles with a total...... signals varies between 7 and 15 m in the interior of the island where the shallow subsurface is not influenced by saltwater intrusion or fine-grained salt marsh sediments. Analysis of common midpoint reflection data constrains the radar wave velocity distribution in the subsurface and facilitates depth...

  10. High-resolution geophysical profiling using a stepped-frequency ground penetrating radar

    Energy Technology Data Exchange (ETDEWEB)

    Noon, D.; Longstaff, D. [The University of Queensland, (Australia)

    1996-05-01

    This paper describes the results of a ground penetrating radar (GPR) system which uses stepped-frequency waveforms to obtain high-resolution geophysical profiles. The main application for this system is the high-resolution mapping of thin coal seam structures, in order to assist surface mining operations in open-cut coal mines. The required depth of penetration is one meter which represents the maximum thickness of coal seams that are designated `thin`. A resolution of five centimeters is required to resolve the minimum thickness of coal (or shale partings) which can be economically recovered in an open-cut coal mine. For this application, a stepped-frequency GPR system has been developed, because of its ultrawide bandwidth (1 to 2 GHz) and high external loop sensitivity (155 dB). The field test results of the stepped-frequency GPR system on a concrete pavement and at two Australian open-cut coal mines are also presented. 7 refs., 5 figs.

  11. Advanced signal processing method for ground penetrating radar feature detection and enhancement

    Science.gov (United States)

    Zhang, Yu; Venkatachalam, Anbu Selvam; Huston, Dryver; Xia, Tian

    2014-03-01

    This paper focuses on new signal processing algorithms customized for an air coupled Ultra-Wideband (UWB) Ground Penetrating Radar (GPR) system targeting highway pavements and bridge deck inspections. The GPR hardware consists of a high-voltage pulse generator, a high speed 8 GSps real time data acquisition unit, and a customized field-programmable gate array (FPGA) control element. In comparison to most existing GPR system with low survey speeds, this system can survey at normal highway speed (60 mph) with a high horizontal resolution of up to 10 scans per centimeter. Due to the complexity and uncertainty of subsurface media, the GPR signal processing is important but challenging. In this GPR system, an adaptive GPR signal processing algorithm using Curvelet Transform, 2D high pass filtering and exponential scaling is proposed to alleviate noise and clutter while the subsurface features are preserved and enhanced. First, Curvelet Transform is used to remove the environmental and systematic noises while maintain the range resolution of the B-Scan image. Then, mathematical models for cylinder-shaped object and clutter are built. A two-dimension (2D) filter based on these models removes clutter and enhances the hyperbola feature in a B-Scan image. Finally, an exponential scaling method is applied to compensate the signal attenuation in subsurface materials and to improve the desired signal feature. For performance test and validation, rebar detection experiments and subsurface feature inspection in laboratory and field configurations are performed.

  12. Ground-penetrating radar research in Belgium: from developments to applications

    Science.gov (United States)

    Lambot, Sébastien; Van Meirvenne, Marc; Craeye, Christophe

    2014-05-01

    Ground-penetrating radar research in Belgium spans a series of developments and applications, including mainly ultra wideband radar antenna design and optimization, non-destructive testing for the characterization of the electrical properties of soils and materials, and high-resolution subsurface imaging in agricultural engineering, archeology and transport infrastructures (e.g., road inspection and pipe detection). Security applications have also been the topic of active research for several years (i.e., landmine detection) and developments in forestry have recently been initiated (i.e., for root zone and tree trunk imaging and characterization). In particular, longstanding research has been devoted to the intrinsic modeling of antenna-medium systems for full-wave inversion, thereby providing an effective way for retrieving the electrical properties of soils and materials. Full-wave modeling is a prerequisite for benefiting from the full information contained in the radar data and is necessary to provide robust and accurate estimates of the properties of interest. Nevertheless, this has remained a major challenge in geophysics and electromagnetics for many years, mainly due to the complex interactions between the antennas and the media as well as to the significant computing resources that are usually required. Efforts have also been dedicated to the development of specific inversion strategies to cope with the complexity of the inverse problems usually dealt with as well as ill-posedness issues that arise from a lack of information in the radar data. To circumvent this last limitation, antenna arrays have been developed and modeled in order to provide additional information. Moreover, data fusion ways have been investigated, by mainly combining GPR data with electromagnetic induction complementary information in joint interpretation analyses and inversion procedures. Finally, inversions have been regularized by combining electromagnetics models together with soil

  13. Efficient multiple layer boundary detection in ground-penetrating radar data using an extended Viterbi algorithm

    Science.gov (United States)

    Smock, Brandon; Wilson, Joseph

    2012-06-01

    In landmine detection using vehicle-mounted ground-penetrating radar (GPR) systems, ground tracking has proven to be an eective pre-processing step. Identifying the ground can aid in the correction of distortions in downtrack radar data, which can result in the reduction of false alarms due to ground anomalies. However, the air-ground interface is not the only layer boundary detectable by GPR systems. Multiple layers can exist within the ground, and these layers are of particular importance because they give rise to anomalous signatures below the ground surface, where target signatures will typically reside. In this paper, an ecient method is proposed for performing multiple ground layer-identication in GPR data. The method is an extension of the dynamic programming-based Viterbi algorithm, nding not only the globally optimal path, which can be associated with the ground surface, but also locally optimal paths that can be associated with distinct layer boundaries within the ground. In contrast with the Viterbi algorithm, this extended method is uniquely suited to detecting not only multiple layers that span the entire antenna array, but also layers that span only a subset of the channels of the array. Furthermore, it is able to accomplish this while retaining the ecient nature of the original Viterbi scheme.

  14. Convolutional neural network based sensor fusion for forward looking ground penetrating radar

    Science.gov (United States)

    Sakaguchi, Rayn; Crosskey, Miles; Chen, David; Walenz, Brett; Morton, Kenneth

    2016-05-01

    Forward looking ground penetrating radar (FLGPR) is an alternative buried threat sensing technology designed to offer additional standoff compared to downward looking GPR systems. Due to additional flexibility in antenna configurations, FLGPR systems can accommodate multiple sensor modalities on the same platform that can provide complimentary information. The different sensor modalities present challenges in both developing informative feature extraction methods, and fusing sensor information in order to obtain the best discrimination performance. This work uses convolutional neural networks in order to jointly learn features across two sensor modalities and fuse the information in order to distinguish between target and non-target regions. This joint optimization is possible by modifying the traditional image-based convolutional neural network configuration to extract data from multiple sources. The filters generated by this process create a learned feature extraction method that is optimized to provide the best discrimination performance when fused. This paper presents the results of applying convolutional neural networks and compares these results to the use of fusion performed with a linear classifier. This paper also compares performance between convolutional neural networks architectures to show the benefit of fusing the sensor information in different ways.

  15. 3D Monitoring under the Keciova Mosque (Casbah-Algier, Algeria) with Ground Penetrating Radar Method

    Science.gov (United States)

    Kadioglu, Selma; Kagan Kadioglu, Yusuf; Deniz, Kiymet; Akin Akyol, Ali

    2014-05-01

    Keciova (Ketchaoua) Mosque, in Casbah-Algiers, the capital of Algeria, is a UNESCO World Heritage Site. Keciova Mosque was originally built in 1612 by the Ottoman Empire. A RAMAC CU II GPR system and a 250 MHz shielded antenna have been employed inside of the Mosque including the Cathedral and inside of the burial chambers under the Cathedral Site on parallel profiles spaced approximately 0.30 m apart to measure data. After applying standard two-dimensional (2D) and three dimensional (3D) imaging techniques, transparent 3D imaging techniques have been used to photograph the foundational infrastructures, buried remains and safety problems of the Mosque. The results showed that we obtained 3D GPR visualization until 12.0 m in depth. Firstly we imaged the base floor including corridors. Then we monitored buried remains under the first ground level between 5.0-7.0 m in depths. Finally we indicated 3D GPR photographs a spectacular protected buried old mosque structures under the second ground level between 9.0-12.0 m in depths. This project has been supported by Republic of Turkey Prime Ministry Turkish Cooperation and Coordination Agency (TIKA). This study is a contribution to the EU funded COST action TU1208, "Civil Engineering Applications of Ground penetrating Radar".

  16. Contextual learning in ground-penetrating radar data using Dirichlet process priors

    Science.gov (United States)

    Ratto, Christopher R.; Morton, Kenneth D., Jr.; Collins, Leslie M.; Torrione, Peter A.

    2011-06-01

    In landmine detection applications, fluctuation of environmental and operating conditions can limit the performance of sensors based on ground-penetrating radar (GPR) technology. As these conditions vary, the classification and fusion rules necessary for achieving high detection and low false alarm rates may change. Therefore, context-dependent learning algorithms that exploit contextual variations of GPR data to alter decision rules have been considered for improving the performance of landmine detection systems. Past approaches to contextual learning have used both generative and discriminative methods to learn a probabilistic mixture of contexts, such as a Gaussian mixture, fuzzy c-means clustering, or a mixture of random sets. However, in these approaches the number of mixture components is pre-defined, which could be problematic if the number of contexts in a data collection is unknown a priori. In this work, a generative context model is proposed which requires no a priori knowledge in the number of mixture components. This was achieved through modeling the contextual distribution in a physics-based feature space with a Gaussian mixture, while also incorporating a Dirichlet process prior to model uncertainty in the number of mixture components. This Dirichlet process Gaussian mixture model (DPGMM) was then incorporated in the previously-developed Context-Dependent Feature Selection (CDFS) framework for fusion of multiple landmine detection algorithms. Experimental results suggest that when the DPGMM was incorporated into CDFS, the degree of performance improvement over conventional fusion was greater than when a conventional fixed-order context model was used.

  17. THE APPLICATION OF GROUND PENETRATING RADAR IN THE HIGHWAY ROAD BED INVESTIGATION

    Institute of Scientific and Technical Information of China (English)

    ZENG Chong; CHEN Chao; XU Shun-fang

    2004-01-01

    Ground penetrating radar (GPR) is a new nondestructive geophysical method for road quality investigation. In this article, a section of the highway joints with the third Yangtze Bridge in Wuhan have been investigated using the RAMAC/GPR system developed by the MAL? GeoScience Company. Various antennas with different frequency were used in the exploration. And the data gathered by the unshielded antenna with frequency in 400 MHz is very well. Then the field data was processed using methods such as trace equalization, F-K filtering, deconvolution filtering and so on. Through the processing, the GPR profile shows the underground structure more clearly. From the processed GPR profile, the sinking and slipping condition of the roadbed can be easily found. Most parts of the roadbed are well, but several parts of the roadbed have sunken or slipped seriously. Contrasts to the shallow seismic section, the GPR profile accords with it very well. It indicates that the GPR method is available and has the high efficiency in the highway roadbed investigation.

  18. A NOVEL SVM FOR GROUND PENETRATING SYNTHETIC APERTURE RADAR LANDMINE DETECTION

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The use of vehicle- or air-borne Ground Penetrating Synthetic Aperture Radar (GPSAR) to quickly detect landmines over large areas is becoming a trend. However, producing too many false alarms in GPSAR landmine detection is a major challenge in practical applications of GPSAR. Support Vector Machine (SVM), employing structural risk minimization theory, does not need large amounts of training data, which makes it suitable for solving the landmine detection problem. In this paper, a novel SVM with a hypersphere instead of a hyperplane classification boundary is proposed for landmine detection in GPSAR. The HyperSphere-SVM (HS-SVM) can be trained with both landmine and clutter data, or with landmine data only, which are called the two-class HS-SVM and the one-class HS-SVM, respectively. The HS-SVM has better generalization capability than the traditional HyperPlane-SVM (HP-SVM) with respect to varying operating conditions. Quantitative comparisons have been made using real data collected with the rail-GPSAR landmine detection system, which show that both the two-class and the one-class HS-SVMs have better detection performance than the HP-SVM.

  19. Ground penetrating radar detection of subsnow liquid overflow on ice-covered lakes in interior Alaska

    Directory of Open Access Journals (Sweden)

    A. Gusmeroli

    2012-07-01

    Full Text Available Lakes are abundant throughout the pan-Arctic region. For many of these lakes ice cover lasts for up to two thirds of the year. This frozen cover allows human access to these lakes, which are therefore used for many subsistence and recreational activities, including water harvesting, fishing, and skiing. Safe access to these lakes may be compromised, however, when, after significant snowfall, the weight of the snow acts on the ice and causes liquid water to spill through weak spots and overflow at the snow-ice interface. Since visual detection of subsnow liquid overflow (SLO is almost impossible our understanding on SLO processes is still very limited and geophysical methods that allow SLO detection are desirable. In this study we demonstrate that a commercially available, lightweight 1GHz, ground penetrating radar system can detect and map extent and intensity of SLO. Radar returns from wet snow-ice interfaces are at least twice as much in strength than returns from dry snow-ice interface. The presence of SLO also affects the quality of radar returns from the base of the lake ice. During dry conditions we were able to profile ice thickness of up to 1 m, conversely, we did not retrieve any ice-water returns in areas affected by SLO.

  20. Sedimentology and Ground-Penetrating Radar Characteristics of a Pleistocene Sandur Deposit

    DEFF Research Database (Denmark)

    Olsen, Henrik; Andreasen, Frank Erik

    1995-01-01

    -upward lithology, terminating with a jökulhlaup episode characterized by large compound dune migration and slack-water draping. Mapping of a more than 200 m long well exposed pitwall and ground-penetrating radar measurements in a 50 × 200 m grid along the pitwall made it possible to outline the three......-dimensional geometry of the jökulhlaup deposit, forming the top part of the succession. The paper describes the sedimentology of the sandur deposits and the application of the ground-penetrating radar technique to sedimentary architecture studies....

  1. Sedimentology and Ground-Penetrating Radar Characteristics of a Pleistocene Sandur Deposit

    DEFF Research Database (Denmark)

    Olsen, Henrik; Andreasen, Frank Erik

    1995-01-01

    -upward lithology, terminating with a jökulhlaup episode characterized by large compound dune migration and slack-water draping. Mapping of a more than 200 m long well exposed pitwall and ground-penetrating radar measurements in a 50 × 200 m grid along the pitwall made it possible to outline the three......-dimensional geometry of the jökulhlaup deposit, forming the top part of the succession. The paper describes the sedimentology of the sandur deposits and the application of the ground-penetrating radar technique to sedimentary architecture studies....

  2. Electromagnetic simulators for Ground Penetrating Radar applications developed in COST Action TU1208

    Science.gov (United States)

    Pajewski, Lara; Giannopoulos, Antonios; Warren, Craig; Antonijevic, Sinisa; Doric, Vicko; Poljak, Dragan

    2017-04-01

    Founded in 1971, COST (European COoperation in Science and Technology) is the first and widest European framework for the transnational coordination of research activities. It operates through Actions, science and technology networks with a duration of four years. The main objective of the COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar" (4 April 2013 - 3 October 2017) is to exchange and increase knowledge and experience on Ground-Penetrating Radar (GPR) techniques in civil engineering, whilst promoting in Europe a wider use of this technique. Research activities carried out in TU1208 include all aspects of the GPR technology and methodology: design, realization and testing of radar systems and antennas; development and testing of surveying procedures for the monitoring and inspection of structures; integration of GPR with other non-destructive testing approaches; advancement of electromagnetic-modelling, inversion and data-processing techniques for radargram analysis and interpretation. GPR radargrams often have no resemblance to the subsurface or structures over which the profiles were recorded. Various factors, including the innate design of the survey equipment and the complexity of electromagnetic propagation in composite scenarios, can disguise complex structures recorded on reflection profiles. Electromagnetic simulators can help to understand how target structures get translated into radargrams. They can show the limitations of GPR technique, highlight its capabilities, and support the user in understanding where and in what environment GPR can be effectively used. Furthermore, electromagnetic modelling can aid the choice of the most proper GPR equipment for a survey, facilitate the interpretation of complex datasets and be used for the design of new antennas. Electromagnetic simulators can be employed to produce synthetic radargrams with the purposes of testing new data-processing, imaging and inversion algorithms, or assess

  3. Ground Penetration Radar (GPR) Studies in Kureyşler Dam Rescue Excavations, Kütahya, Turkey

    Science.gov (United States)

    Mutlu, S.; Tün, M.; Pekkan, E.; Ecevitoğlu, B.; Guney, Y.

    2016-12-01

    Kureyşler Dam Rescue Excavations shows up as an important archaeological study implemented in Kütahya. It provides valuable data on and deepens our understanding of the Inner Western Anatolian region alongside Seyitömer and Çiledir Mound Excavations. The rescue excavations were started with the aim of determining the cultural artefacts that would be flooded by Kureyşler Irrigation Dam. Rescue excavations in archaeology, mostly called salvage archaeology, is archaeological survey and excavation applied in areas revealed by some constructions. These works must be undertaken in the shortest possible time, unlike traditional survey and excavation. Use of ground penetrating radar (GPR) allows field archaeologists to quickly discover and map buried archaeological features. This study describes the use of GPR during a rescue archaeology campaign at the Kureyşler Irrigation Dam, in Kütahya (Turkey). Closely spaced GPR transects were collected in a grid-based approach, covering three different areas from the site, using GSSI Sir 3000 System, with antennae frequency of 400MHz. Ground penetrating radar data were evaluated with a few commercial software. According to the interpretation of geophysical data, we suggested some excavation sites. The ancient ruins were found in the suggested area quite successful.

  4. Snow Mass Quantification and Avalanche Victim Search By Ground Penetrating Radar

    Science.gov (United States)

    Jaedicke, C.

    Ground penetrating radar (GPR) systems can be used in many applications of snow and ice research. The information from the GPR is interpreted to identify layers, ob- ject and different structures in the snow. A commercially available GPR system was further developed to work in the rough environment of snow and ice. The applied GPR is a 900 MHz system that easily reaches snow depths of ten meters. The system is cal- ibrated by several manual snow depth measurements during each survey. The depth resolution is depending on the snow type and ranges around +/- 0.1 m. The GPR sys- tem carried along a line of interest and is triggered by an odometer wheel at regular adjustable steps. All equipment is mounted in a sledge and is moved by a snow mo- bile over the surface. This setup allows the efficient coverage of several kilometers of profiles. The radar profiles give a real time two-dimensional impression of structures and objects and the interface between snow and underlying ground. The actual radar profile is shown on a screen on the sledge allowing the immediate marking of objects and structures. During the past three years the instrument was successfully used for the study of snow distributions, for the detection of glacier crevasses under the snow cover and for the search of avalanche victims in avalanche debris. The results show the capability of the instrument to detect persons and objects in the snow cover. In the future this could be new tool for avalanche rescue operations. Today the size and weight of the system prevents the access to very steep slopes and areas not accessible for snowmobile. Further development will decrease the size of the system and make it a valuable tool to quantify the snow mass in avalanche release zones and run out areas.

  5. Raw Ground Penetrating Radar Data,Taku Glacier, Alaska; 2013

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Common-offset GPR surveys were conducted with a Sensors and Software 500-MHz Pulse Ekko Pro system. We collected data from the ground, towed behind a researcher on...

  6. Raw Ground Penetrating Radar Data, Valdez Glacier, Alaska; 2013

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Common-offset GPR surveys were conducted with a Sensors and Software 500-MHz Pulse Ekko Pro system. We collected data from the ground, towed behind a researcher on...

  7. Raw Ground Penetrating Radar Data, Wolverine Glacier, Alaska; 2013

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Common-offset GPR surveys were conducted with a Sensors and Software 500-MHz Pulse Ekko Pro system. We collected data from the ground, towed behind a researcher on...

  8. Raw Ground Penetrating Radar Data, Eureka Glacier, Alaska; 2013

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Common-offset GPR surveys were conducted with a Sensors and Software 500-MHz Pulse Ekko Pro system. We collected data from the ground, towed behind a researcher on...

  9. Raw Ground Penetrating Radar Data, Scott Glacier, Alaska; 2013

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Common-offset GPR surveys were conducted with a Sensors and Software 500-MHz Pulse Ekko Pro system. We collected data from the ground, towed behind a researcher on...

  10. Raw Ground Penetrating Radar Data, Eklutna Glacier, Alaska; 2013

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Common-offset GPR surveys were conducted with a Sensors and Software 500-MHz Pulse Ekko Pro system. We collected data from the ground, towed behind a researcher on...

  11. Raw Ground Penetrating Radar Data, Gulkana Glacier, Alaska; 2013

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Common-offset GPR surveys were conducted with a Sensors and Software 500-MHz Pulse Ekko Pro system. We collected data from the ground, towed behind a researcher on...

  12. Raw Ground Penetrating Radar Data, Wolverine Glacier, Alaska; 2013

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Common-offset GPR surveys were conducted with a Sensors and Software 500-MHz Pulse Ekko Pro system. We collected data from the ground, towed behind a researcher on...

  13. Change Detection Using Down-Looking Ground-Penetrating Radar

    Science.gov (United States)

    2014-04-01

    collected using real-time kinematic ( RTK ) DGPS, which is accurate to a few centimeters. RTK -DGPS requires the use of a base station at known, surveyed...Since the targets are typically less than 1/2 meter in size, linking distances are approximately the same length. If a GPS system without differential...an alarm from the same subsurface object generated from a prior excursion. Although some types of navigation systems can enhance the accuracy of GPS

  14. The ACE-DTU Planar Near-Field Ground Penetrating Radar Antenna Test Facility

    DEFF Research Database (Denmark)

    Lenler-Eriksen, Hans-Rudolph; Meincke, Peter

    2004-01-01

    The ACE-DTU planar near-field ground penetrating radar (GPR) antenna test facility is used to measure the plane-wave transmitting spectrum of a GPR loop antenna close to the air-soil interface by means of a probe buried in soil. Probe correction is implemented using knowledge about the complex...

  15. A 2.5-D Diffraction Tomography Inversion Scheme for Ground Penetrating Radar

    DEFF Research Database (Denmark)

    Meincke, Peter

    1999-01-01

    A new 2.5-D inversion scheme is derived for ground penetrating radar (GPR) that applies to a monostatic fixed-offset measurement configuration. The inversion scheme, which is based upon the first Born approximation and the pseudo-inverse operator, takes rigorously into account the planar air...

  16. Location of Agricultural Drainage Pipes and Assessment of Agricultural Drainage Pipe Conditions Using Ground Penetrating Radar

    Science.gov (United States)

    Methods are needed to not only locate buried agricultural drainage pipe, but to also determine if the pipes are functioning properly with respect to water delivery. The primary focus of this research project was to confirm the ability of ground penetrating radar (GPR) to locate buried drainage pipe ...

  17. Ground Penetrating Radar: Ultra-wideband radars for improvised explosive devices and landmine detection

    NARCIS (Netherlands)

    Yarovoy, A.

    2008-01-01

    For last two decades Ultra-Wideband Ground Penetrating Radars seemed to be a useful tool for detection and classification of landmines and improvised explosive devices (IEDs). However limitations of radar technology considerably limited operational use of these radars. Recent research at TU Delft so

  18. Ground Penetrating Radar: Ultra-wideband radars for improvised explosive devices and landmine detection

    OpenAIRE

    Yarovoy, A.

    2008-01-01

    For last two decades Ultra-Wideband Ground Penetrating Radars seemed to be a useful tool for detection and classification of landmines and improvised explosive devices (IEDs). However limitations of radar technology considerably limited operational use of these radars. Recent research at TU Delft solves the bottleneck problems.

  19. Measurement of Plane-Wave Spectra of Ground Penetrating Radar Antennas

    DEFF Research Database (Denmark)

    Lenler-Eriksen, Hans-Rudolph; Meincke, Peter

    2005-01-01

    The plane-wave transmitting spectrum of a ground penetrating radar (GPR) loop antenna close to the air-soil interface is measured by means of a probe buried in soil. Probe correction is implemented based upon knowledge about the complex permittivity of the soil and the current distribution...

  20. Delineation of rockburst fractures with ground penetrating radar in the Witwatersrand Basin, South Africa

    CSIR Research Space (South Africa)

    Grodner, M

    2001-09-01

    Full Text Available into the excavation) is preconditioning. Ground Penetrating Radar (GPR) is used to quantify the change in fracture pattern with preconditioning. It is found that both the intensity and depth to which fracturing occurs ahead of the mining face increased, thereby...

  1. The ACE-DTU Planar Near-Field Ground Penetrating Radar Antenna Test Facility

    DEFF Research Database (Denmark)

    Lenler-Eriksen, Hans-Rudolph; Meincke, Peter

    2004-01-01

    The ACE-DTU planar near-field ground penetrating radar (GPR) antenna test facility is used to measure the plane-wave transmitting spectrum of a GPR loop antenna close to the air-soil interface by means of a probe buried in soil. Probe correction is implemented using knowledge about the complex...

  2. Measurement of Plane-Wave Spectra of Ground Penetrating Radar Antennas

    DEFF Research Database (Denmark)

    Lenler-Eriksen, Hans-Rudolph; Meincke, Peter

    2005-01-01

    The plane-wave transmitting spectrum of a ground penetrating radar (GPR) loop antenna close to the air-soil interface is measured by means of a probe buried in soil. Probe correction is implemented based upon knowledge about the complex permittivity of the soil and the current distribution...

  3. Uncertainty in peat volume and soil carbon estimated using ground-penetrating radar and probing

    Science.gov (United States)

    Andrew D. Parsekian; Lee Slater; Dimitrios Ntarlagiannis; James Nolan; Stephen D. Sebestyen; Randall K. Kolka; Paul J. Hanson

    2012-01-01

    Estimating soil C stock in a peatland is highly dependent on accurate measurement of the peat volume. In this study, we evaluated the uncertainty in calculations of peat volume using high-resolution data to resolve the three-dimensional structure of a peat basin based on both direct (push probes) and indirect geophysical (ground-penetrating radar) measurements. We...

  4. GSTAMIDS ground-penetrating radar: data processing algorithms

    Science.gov (United States)

    Sower, Gary D.; Kilgore, Roger; Roman, Jaime R.

    2001-10-01

    The Ground Standoff Mine Detection System is now in the Engineering, Manufacturing and Development (EMD) Block 0 phase for USA CECOM. This paper describes the data processing algorithms for the GPR that are used to extract the features used for anti-tank (AT) mine detection; those used for pre-processing the data re included herein to show the enhancement of the mine signals. A key feature of the processing is the acquisition of a clean radar return signal from undisturbed soil, which is then deconvolved from each data frame waveform. This soil signal is an estimate of the system impulse response function, save for the magnitude of the reflection coefficient of the soil, which is a scalar to first order. Deconvolution thus gives the impulse response function of the buried mines, a strong enhancement over their raw measured signals. A matched filter test statistic is generated to discriminate between mines and background. Discrimination algorithms using hidden Markov model processing are describe in a paper by PD Gader et al. These processes were developed in MATLAB using dat files acquired and stored from prototype GPR systems and then refined with data form production units. The MATLAB code is then converted into C code for use on the real-time processor on GSTAMIDS. The C code modules are run as dynamic library links in MATLAB for verification. The GPR sensor suite hardware and its physical incorporation into the GSTAMIDS sensor modules are described fully in a companion paper.

  5. Ground-penetrating radar evaluation of bridge decks

    Science.gov (United States)

    Roberts, Glenn E.

    1995-05-01

    Radar has emerged as a valuable non-destructive test method for evaluating the condition of New Hampshire bridge decks. It allows the inspector to 'see' the top surface of the portland cement concrete deck which is typically covered with asphalt pavement. Radar is also very 'customer friendly' in that it allows inspectors to evaluate the bridge decks without closing travel lanes or otherwise impeding traffic flow in any way. This paper discusses the inspection needs of the New Hampshire Department of Transportation which necessitated the use of radar, as well as a history of its selection, development, and incorporation into New Hampshire's bridge management system.

  6. Devonian lacustrine shore zone architecture imaged with ground penetrating radar

    DEFF Research Database (Denmark)

    Andrews, Steven D.; Moreau, Julien; Archer, Stuart

    deposition was limited to intermittent events where sediment was laid down on a water saturated substrate. Some of these may have occurr­­­ed subaqueously as small scale turbidity flows. High resolution fluctuations in lake level resulted in periodic short lived reworking events along the lake margin which...... produced amalgamated sands, forming low relief bars. Shore zone reworking is likely to have occurred over a wide area as the lake margin migrated back and forth, and gradually transgressed. Continued transgression forced fluvial systems back towards the basin margin....

  7. Devonian lacustrine shore zone architecture imaged with ground penetrating radar

    DEFF Research Database (Denmark)

    Andrews, Steven D.; Moreau, Julien; Archer, Stuart

    of these units. The cycles are on average 15 m thick and comprise deep lake, perennial lake, playa and shore zone facies (2 to 3.5 m in thickness). High resolution sedimentary logging and the construction of photo-panels were combined with high resolution GPR profiling (250 MHz). To ensure close ties between...... produced amalgamated sands, forming low relief bars. Shore zone reworking is likely to have occurred over a wide area as the lake margin migrated back and forth, and gradually transgressed. Continued transgression forced fluvial systems back towards the basin margin....

  8. Underwater Acoustic Beacon Location System

    Science.gov (United States)

    2016-12-23

    transpose operator is a standard operator in linear or matrix algebra . The transpose operator converts the row vector   T aaaa z,y,x=P to a column...February 2017 The below identified patent application is available for licensing. Requests for information should be addressed to...300087 1 of 31 UNDERWATER ACOUSTIC BEACON LOCATION SYSTEM [0001] The present application claims the benefit of United States Provisional

  9. COST Action TU1208 - Working Group 3 - Electromagnetic modelling, inversion, imaging and data-processing techniques for Ground Penetrating Radar

    Science.gov (United States)

    Pajewski, Lara; Giannopoulos, Antonios; Sesnic, Silvestar; Randazzo, Andrea; Lambot, Sébastien; Benedetto, Francesco; Economou, Nikos

    2017-04-01

    opportunity of testing and validating, against reliable data, their electromagnetic-modelling, inversion, imaging and processing algorithms. One of the most interesting dataset comes from the IFSTTAR Geophysical Test Site, in Nantes (France): this is an open-air laboratory including a large and deep area, filled with various materials arranged in horizontal compacted slices, separated by vertical interfaces and water-tighted in surface; several objects as pipes, polystyrene hollows, boulders and masonry are embedded in the field. Data were collected by using nine different GPR systems and at different frequencies ranging from 200 MHz to 1 GHz. Moreover, some sections of this test site were modelled by using gprMax and the commercial software CST Microwave Studio. Hence, both experimental and synthetic data are available. Further interesting datasets were collected on roads, bridges, concrete cells, columns - and more. (v) WG3 contributed to the TU1208 Education Pack, an open educational package conceived to teach GPR in University courses. (vi) WG3 was very active in offering training activities. The following courses were successfully organised: Training School (TS) "Microwave Imaging and Diagnostics" (in cooperation with the European School of Antennas; 1st edition: Madonna di Campiglio, Italy, March 2014, 2nd edition: Taormina, Italy, October 2016); TS "Numerical modelling of Ground Penetrating Radar using gprMax" (Thessaloniki, Greece, November 2015); TS "Electromagnetic Modelling Techniques for Ground Penetrating Radar" (Split, Croatia, November 2016). Moreover, WG3 organized a workshop on "Electromagnetic modelling with the Finite-Difference Time-Domain technique" (Nantes, France, February 2014) and a workshop on "Electromagnetic modelling and inversion techniques for GPR" (Davos, Switzerland, April 2016) within the 2016 European Conference on Antennas and Propagation (EuCAP). Acknowledgement: The Authors are deeply grateful to COST (European COoperation in Science and

  10. Fusion of forward looking infrared and ground penetrating radar for improved stopping distances in landmine detection

    Science.gov (United States)

    Malof, Jordan M.; Morton, Kenneth D.; Collins, Leslie M.; Torrione, Peter A.

    2014-06-01

    Ground penetrating radar (GPR) is a popular sensing modality for buried threat detection that offers low false alarm rates (FARs), but suffers from a short detection stopping or standoff distance. This short stopping distance leaves little time for the system operator to react when a threat is detected, limiting the speed of advance. This problem arises, in part, because of the way GPR data is typically processed. GPR data is first prescreened to reduce the volume of data considered for higher level feature-processing. Although fast, prescreening introduces latency that delays the feature processing and lowers the stopping distance of the system. In this work we propose a novel sensor fusion framework where a forward looking infrared (FLIR) camera is used as a prescreener, providing suspicious locations to the GPRbased system with zero latency. The FLIR camera is another detection modality that typically yields a higher FAR than GPR while offering much larger stopping distances. This makes it well-suited in the role of a zero-latency prescreener. In this framework, GPR-based feature processing can begin without any latency, improving stopping distances. This framework was evaluated using well-known FLIR and GPR detection algorithms on a large dataset collected at a Western US test site. Experiments were conducted to investigate the tradeoff between early stopping distance and FAR. The results indicate that earlier stopping distances are achievable while maintaining effective FARs. However, because an earlier stopping distance yields less data for feature extraction, there is a general tradeoff between detection performance and stopping distance.

  11. Using pattern recognition to automatically localize reflection hyperbolas in data from ground penetrating radar

    Science.gov (United States)

    Maas, Christian; Schmalzl, Jörg

    2013-08-01

    Ground Penetrating Radar (GPR) is used for the localization of supply lines, land mines, pipes and many other buried objects. These objects can be recognized in the recorded data as reflection hyperbolas with a typical shape depending on depth and material of the object and the surrounding material. To obtain the parameters, the shape of the hyperbola has to be fitted. In the last years several methods were developed to automate this task during post-processing. In this paper we show another approach for the automated localization of reflection hyperbolas in GPR data by solving a pattern recognition problem in grayscale images. In contrast to other methods our detection program is also able to immediately mark potential objects in real-time. For this task we use a version of the Viola-Jones learning algorithm, which is part of the open source library "OpenCV". This algorithm was initially developed for face recognition, but can be adapted to any other simple shape. In our program it is used to narrow down the location of reflection hyperbolas to certain areas in the GPR data. In order to extract the exact location and the velocity of the hyperbolas we apply a simple Hough Transform for hyperbolas. Because the Viola-Jones Algorithm reduces the input for the computational expensive Hough Transform dramatically the detection system can also be implemented on normal field computers, so on-site application is possible. The developed detection system shows promising results and detection rates in unprocessed radargrams. In order to improve the detection results and apply the program to noisy radar images more data of different GPR systems as input for the learning algorithm is necessary.

  12. Vehicle-mounted ground penetrating radar (Mine Stalker III) field evaluation in Angola

    Science.gov (United States)

    Laudato, Stephen; Hart, Kerry; Nevard, Michael; Lauziere, Steven; Grant, Shaun

    2014-05-01

    The U.S. Department of Defense Humanitarian Demining Research and Development (HD R&D) Program, Non-Intrusive Inspection Technology (NIITEK), Inc. and The HALO Trust have over the last decade funded, developed and tested various prototype vehicle mounted ground penetrating radar (GPR) systems named the Mine Stalker. The HD R&D Program and NIITEK developed the Mine Stalker to detect low metal anti-tank (LM-AT) mines in roads. The country of Angola is severely affected by LM-AT mines in and off road, some of which are buried beyond the effective range of detection sensors current used in country. The threat from LM-AT mines such as the South African Number 8 (No. 8) and the Chinese Type 72 (72AT) still persist from Angola's 30 years of civil war. These LM-AT threats are undetectable at depths greater than 5 to 10 centimeters using metal detection technology. Clearing commerce routes are a critical requirement before Angola can rebuild its infrastructure and improve safety conditions for the local populace. The Halo Trust, a non-governmental demining organization (NGO) focused on demining and clearance of unexploded ordnance (UXO), has partnered with the HD R&D Program to conduct an operational field evaluation (OFE) of the Mine Stalker III (MS3) in Angola. Preliminary testing and training efforts yielded encouraging results. This paper presents a review of the data collected, testing results, system limitations and deficiencies while operating in a real world environment. Our goal is to demonstrate and validate this technology in live minefield environments, and to collect data to prompt future developments to the system.

  13. Attribute-driven transfer learning for detecting novel buried threats with ground-penetrating radar

    Science.gov (United States)

    Colwell, Kenneth A.; Collins, Leslie M.

    2016-05-01

    Ground-penetrating radar (GPR) technology is an effective method of detecting buried explosive threats. The system uses a binary classifier to distinguish "targets", or buried threats, from "nontargets" arising from system prescreener false alarms; this classifier is trained on a dataset of previously-observed buried threat types. However, the threat environment is not static, and new threat types that appear must be effectively detected even if they are not highly similar to every previously-observed type. Gathering a new dataset that includes a new threat type is expensive and time-consuming; minimizing the amount of new data required to effectively detect the new type is therefore valuable. This research aims to reduce the number of training examples needed to effectively detect new types using transfer learning, which leverages previous learning tasks to accelerate and improve new ones. Further, new types have attribute data, such as composition, components, construction, and size, which can be observed without GPR and typically are not explicitly included in the learning process. Since attribute tags for buried threats determine many aspects of their GPR representation, a new threat type's attributes can be highly relevant to the transfer-learning process. In this work, attribute data is used to drive transfer learning, both by using attributes to select relevant dataset examples for classifier fusion, and by extending a relevance vector machine (RVM) model to perform intelligent attribute clustering and selection. Classification performance results for both the attribute-only case and the low-data case are presented, using a dataset containing a variety of threat types.

  14. Ground Penetrating Radar (GPR) Signatures of Lacustrine Soils in Volcanic Basins of Mexico

    Science.gov (United States)

    Carreon-Freyre, D.; Oleschko, K.; Cerca, M.

    2002-12-01

    Ground Penetrating Radar (GPR) profiles have been collected in volcanic and lacustrine basins of Mexico in order to obtain radar signatures and correlate electromagnetic wave propagation with their near-surface stratigraphy. Study sites included Pleistocene to Recent lacustrine sequences in Chalco and Texcoco, near Mexico City, and a Pliocene to Quaternary fluvio-lacustrine sequence in the Queretaro Valley, 250 Km to the northwest. All the sequences present alterning layers of soils, fluvio-lacustrine sediments, pyroclastic and volcanic rocks. GPR method is used because of the sensitivity of the propagation of electromagnetic waves to the granulometric variations and water content of sediments (water molecules polarization). Profiles were carried out with a Zond 12c GPR (Radar Systems Inc.), using four main prospecting frequencies: 2000, 900, 300 and 100 MHz. The purpose of using these frequencies is to evaluate different ranges of depths of investigation and resolution for each site and to relate attenuation and variations in amplitude with impedances and reflection coefficients for stratigraphic associations such as clay-sand, silt-clay and pyroclastics-silt. The analysis of multiple sets of profiles in the studied areas and their correlation with the observed near-surface stratigraphy permits the identification of radar signatures for each depositional condition. GPR characterization also allowed to associate radar signatures with the evolution of fracturing within the sequence. In particular, the Chalco and Queretaro sites are affected by fracturing, an increasing problem in several urbanized areas of Mexico and the world. This phenomenon is generally associated to ground-water withdrawal but its geometry is related closely to the regional structural pattern. Another factor that influences the propagation and morphology of near-surface fracturing in volcanic valleys is their highly heterogeneous stratigraphy. Therefore, the propagation of electromagnetic waves

  15. Fusion of ground-penetrating radar and electromagnetic induction sensors for landmine detection and discrimination

    Science.gov (United States)

    Kolba, Mark P.; Torrione, Peter A.; Collins, Leslie M.

    2010-04-01

    Ground penetrating radar (GPR) and electromagnetic induction (EMI) sensors provide complementary capabilities in detecting buried targets such as landmines, suggesting that the fusion of GPR and EMI modalities may provide improved detection performance over that obtained using only a single modality. This paper considers both pre-screening and the discrimination of landmines from non-landmine objects using real landmine data collected from a U.S. government test site as part of the Autonomous Mine Detection System (AMDS) landmine program. GPR and EMI pre-screeners are first reviewed and then a fusion pre-screener is presented that combines the GPR and EMI prescreeners using a distance-based likelihood ratio test (DLRT) classifier to produce a fused confidence for each pre-screener alarm. The fused pre-screener is demonstrated to provide substantially improved performance over the individual GPR and EMI pre-screeners. The discrimination of landmines from non-landmine objects using feature-based classifiers is also considered. The GPR feature utilized is a pre-processed, spatially filtered normalized energy metric. Features used for the EMI sensor include model-based features generated from the AETC model and a dipole model as well as features from a matched subspace detector. The EMI and GPR features are then fused using a random forest classifier. The fused classifier performance is superior to the performance of classifiers using GPR or EMI features alone, again indicating that performance improvements may be obtained through the fusion of GPR and EMI sensors. The performance improvements obtained both for pre-screening and for discrimination have been verified by blind test results scored by an independent U.S. government contractor.

  16. Time-lapse 3D ground-penetrating radar during plot-scale infiltration experiments

    Science.gov (United States)

    Allroggen, Niklas; Jackisch, Conrad; Tronicke, Jens

    2016-04-01

    In electrical resistive soils, surface-based ground-penetrating radar (GPR) is known as the geophysical tool providing the highest spatial resolution. Thus, 2D and 3D GPR surveys are commonly used for imaging subsurface structures or estimating soil moisture content. Due to its sensitivity to soil moisture and its non-invasive character, GPR provides a large potential to monitor soil moisture variation at high temporal and spatial resolution. As shown in previous experiments, the acquisition of time-lapse GPR data under field conditions requires a high data quality in terms of repeatability as well as spatial and temporal resolution. We present hydrogeophysical field experiments at the plot scale (1m x 1m), during which we record time-lapse 3D GPR. For GPR data acquisition, we use a pulseEKKO PRO GPR system equipped with a pair of 500 MHz antennas in combination with a specially designed metal-free measuring platform. Additionally, we collect tracer and soil moisture data, which are used to improve the interpretation of the GPR data with special focus on preferential flow paths and their structured advective flow field. After an accurate time-lapse GPR data processing, we compare 3D reflection events before and after infiltration and quantitatively interpret their relative time-shift in terms of soil moisture variations. Thereby, we are able to account for basically all of the infiltrated water. The first experiments demonstrate the general applicability of our experimental approach but are limited by the number of acquired time steps and measurement during the sprinkling period (the time of the highest temporal dynamics) are not possible at all. Based on this experience we redesign our experimental setup to continuously collect GPR data during irrigation and infiltration. Thereby, we strongly increase the temporal resolution of our measurements, improve the interpretability of the GPR data, and monitor the temporal and spatial dynamics of shallow subsurface

  17. Mapping Spatial Moisture Content of Unsaturated Agricultural Soils with Ground-Penetrating Radar

    Science.gov (United States)

    Shamir, O.; Goldshleger, N.; Basson, U.; Reshef, M.

    2016-06-01

    Soil subsurface moisture content, especially in the root zone, is important for evaluation the influence of soil moisture to agricultural crops. Conservative monitoring by point-measurement methods is time-consuming and expensive. In this paper we represent an active remote-sensing tool for subsurface spatial imaging and analysis of electromagnetic physical properties, mostly water content, by ground-penetrating radar (GPR) reflection. Combined with laboratory methods, this technique enables real-time and highly accurate evaluations of soils' physical qualities in the field. To calculate subsurface moisture content, a model based on the soil texture, porosity, saturation, organic matter and effective electrical conductivity is required. We developed an innovative method that make it possible measures spatial subsurface moisture content up to a depth of 1.5 m in agricultural soils and applied it to two different unsaturated soil types from agricultural fields in Israel: loess soil type (Calcic haploxeralf), common in rural areas of southern Israel with about 30% clay, 30% silt and 40% sand, and hamra soil type (Typic rhodoxeralf), common in rural areas of central Israel with about 10% clay, 5% silt and 85% sand. Combined field and laboratory measurements and model development gave efficient determinations of spatial moisture content in these fields. The environmentally friendly GPR system enabled non-destructive testing. The developed method for measuring moisture content in the laboratory enabled highly accurate interpretation and physical computing. Spatial soil moisture content to 1.5 m depth was determined with 1-5% accuracy, making our method useful for the design of irrigation plans for different interfaces.

  18. MAPPING SPATIAL MOISTURE CONTENT OF UNSATURATED AGRICULTURAL SOILS WITH GROUND-PENETRATING RADAR

    Directory of Open Access Journals (Sweden)

    O. Shamir

    2016-06-01

    Full Text Available Soil subsurface moisture content, especially in the root zone, is important for evaluation the influence of soil moisture to agricultural crops. Conservative monitoring by point-measurement methods is time-consuming and expensive. In this paper we represent an active remote-sensing tool for subsurface spatial imaging and analysis of electromagnetic physical properties, mostly water content, by ground-penetrating radar (GPR reflection. Combined with laboratory methods, this technique enables real-time and highly accurate evaluations of soils' physical qualities in the field. To calculate subsurface moisture content, a model based on the soil texture, porosity, saturation, organic matter and effective electrical conductivity is required. We developed an innovative method that make it possible measures spatial subsurface moisture content up to a depth of 1.5 m in agricultural soils and applied it to two different unsaturated soil types from agricultural fields in Israel: loess soil type (Calcic haploxeralf, common in rural areas of southern Israel with about 30% clay, 30% silt and 40% sand, and hamra soil type (Typic rhodoxeralf, common in rural areas of central Israel with about 10% clay, 5% silt and 85% sand. Combined field and laboratory measurements and model development gave efficient determinations of spatial moisture content in these fields. The environmentally friendly GPR system enabled non-destructive testing. The developed method for measuring moisture content in the laboratory enabled highly accurate interpretation and physical computing. Spatial soil moisture content to 1.5 m depth was determined with 1–5% accuracy, making our method useful for the design of irrigation plans for different interfaces.

  19. Oil Detection In and Under Sea Ice Using Ground-Penetrating Radar

    Science.gov (United States)

    Steinbronn, L.; Bradford, J.; Liberty, L.; Dickins, D.; Brandvik, P. J.

    2007-12-01

    Marine oil spills can occur in the Arctic due to pipeline breaks or leaks and spills from storage or production facilities. Depending on the time of year and scenario, a portion or all of the spill may become trapped under and/or encapsulated within the sea ice sheet. The current methods for locating spilled oil include visually inspecting drilled ice cores or sending divers under the ice. Speed is a key issue in oil clean-up. A non-invasive method of detecting oil quickly and reliably would greatly facilitate the clean-up and lessen the impact on the environment. First-year ice thicknesses of 0.5-2.0 m, typical of the Arctic region, can be well-resolved using radar. Oil film thicknesses can range from a few mm to 20 cm depending on the ice-water interface topography. For typical conditions a frequency of 500 MHz gives a 1/4 wavelength limit of 7 cm; therefore a typical spill scenario is a thin-bed problem for ground-penetrating radar (GPR). Interference due to thin-beds may cause amplitude, phase and frequency anomalies in the reflected wavelet. In April 2006, SINTEF conducted a contained oil-spill under natural Arctic sea ice conditions in a fjord on Svalbard. Using data collected during that experiment from a 500 MHz antenna and complex trace analysis we computed the instantaneous frequency, instantaneous phase and the envelope function and found significant differences in the data before and after the oil was inserted. These results demonstrated the potential of GPR to be a practical system for oil in ice detection under certain conditions. As a follow-on to the 2006 project, we have undertaken a detailed modeling effort to estimate GPR response to specific variables, such as ice and oil thicknesses, ice salinity and temperature.

  20. Ground-penetrating radar insight into a coastal aquifer: the freshwater lens of Borkum Island

    Directory of Open Access Journals (Sweden)

    J. Igel

    2013-02-01

    Full Text Available Freshwater lenses, as important resource for drinking water, are sensitive to climate changes and sea level rise. To simulate this impact on the groundwater systems, hydraulic subsurface models have to be designed. Geophysical techniques can provide information for generating realistic models. The aim of our work is to show how ground-penetrating radar (GPR investigations can contribute to such hydrological simulations. In the pilot area, Borkum island, GPR was used to map the shape of the groundwater table (GWT and to characterise the aquifer.

    In total, 20 km of constant offset (CO profiles were measured with centre frequencies of 80 and 200 MHz. Wave velocities were determined by common midpoint (CMP measurements and vertical radar profiling (VRP in a monitoring well. The 80 MHz CO data show a clear reflection at the groundwater table, whereas the reflection is weaker for the 200 MHz data. After correcting the GPR water tables for the capillary rise, they are in good accordance with the pressure heads of the observation wells in the area. In the centre of the island, the groundwater table is found up to 3.5 m above sea level, however it is lower towards the coastline and marshland. Some local depressions are observed in the region of dune valleys and around pumping stations of the local water supplier. GPR also reveals details within the sediments and highly-permeable aeolian sands can be distinguished from less-permeable marine sediments. Further, a silt loam layer below the water table could be mapped on a large area. The reflection characteristics indicates scattered erosion channels in this layer that cause it to be an aquitard with some leakage.

    GPR provides a high resolution map of the groundwater table and insight into the stratigraphy of the sediments and their hydraulic properties. This is valuable complementary information to the observation of sparsely distributed monitoring wells as input to hydraulic simulation.

  1. Combining ground penetrating radar and electromagnetic induction for industrial site characterization

    Science.gov (United States)

    Van De Vijver, Ellen; Van Meirvenne, Marc; Saey, Timothy; De Smedt, Philippe; Delefortrie, Samuël; Seuntjens, Piet

    2014-05-01

    soil electrical conductivity (ECa) and magnetic susceptibility (MSa). For both methods one of the latest-generation instruments was used. GPR data were collected using a 3d-Radar stepped-frequency system with multi-channel antenna design. For EMI, this was the multi-receiver DUALEM-21S sensor. This sensor contains four different transmitter-receiver coil pair configurations, which allows to record the ECa and MSa for four different soil volumes at the same time, thereby providing information about the vertical variation of these soil properties. Both the EMI and GPR survey were performed in a mobile set-up with real-time georeferencing to obtain a high-resolution coverage of the area. The results of both surveys were validated with conventional site characterization that was conducted for a soil contamination investigation, and ancillary information such as aerial photographs and utility maps. Both methods were compared on their performance in detecting different types of anomalies. We report on the successes and failures with this multi-sensor approach. The authors acknowledge funding by COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar"

  2. Hydrogeological characterisation using cross-borehole ground penetration radar and electrical resistivity tomography

    DEFF Research Database (Denmark)

    Zibar, Majken Caroline Looms

    2007-01-01

    . The methods provided estimates of soil moisture content and electrical resistivity variations among 12 m deep boreholes located 5 – 7 m apart. The moisture content change following natural precipitation was observed to be practically negligible, providing minimal information to constrain the dynamic...... was characterized by ~30 m thick unsaturated zone consisting mainly of sands of varying coarseness. Following an instrumentation of 16 boreholes two geophysical methods (cross-borehole ground penetrating radar and electrical resistivity tomography) were applied during natural precipitation and forced infiltration...... properties of the subsurface. On the other hand, volumetric moisture content variations of up to 5% were observed during a 20-day long forced infiltration experiment. The cross-borehole electrical resistance tomography and ground penetrating radar data collected during this experiment were subsequently...

  3. Monitoring of landfill leachate dispersion using reflectance spectroscopy and ground-penetrating radar.

    Science.gov (United States)

    Splajt, T; Ferrier, G; Frostick, L E

    2003-09-15

    The utility of ground-penetrating radar and reflectance spectroscopy in the monitoring of landfill sites has been investigated. Strong correlations between red edge inflection position and chlorophyll and heavy metal concentrations have been demonstrated from grassland species affected by leachate contamination of the soil adjacent to the landfill test site. This study demonstrated that reflectance spectroscopy can identify vegetation affected by leachate-contaminated soil at a range of spatial resolutions. To identify the vegetation affected by leachate contamination, the spectroradiometer must have contiguous bands at sufficient spectral resolution over the critical wave range that measures chlorophyll absorption and the red edge (between 650 and 750 nm). The utility of ground-penetrating radar data to identify leachate escaping from breakout points in the contaminant wall has also been demonstrated. An integrated approach using these techniques, combined with field and borehole sampling and contaminant migration modeling, offers a possible cost-effective monitoring approach for landfill sites.

  4. Hydrogeological characterisation using cross-borehole ground penetration radar and electrical resistivity tomography

    DEFF Research Database (Denmark)

    Zibar, Majken Caroline Looms

    2007-01-01

    . The methods provided estimates of soil moisture content and electrical resistivity variations among 12 m deep boreholes located 5 – 7 m apart. The moisture content change following natural precipitation was observed to be practically negligible, providing minimal information to constrain the dynamic...... was characterized by ~30 m thick unsaturated zone consisting mainly of sands of varying coarseness. Following an instrumentation of 16 boreholes two geophysical methods (cross-borehole ground penetrating radar and electrical resistivity tomography) were applied during natural precipitation and forced infiltration...... properties of the subsurface. On the other hand, volumetric moisture content variations of up to 5% were observed during a 20-day long forced infiltration experiment. The cross-borehole electrical resistance tomography and ground penetrating radar data collected during this experiment were subsequently...

  5. Work flow of signal processing data of ground penetrating radar case of rigid pavement measurements

    Energy Technology Data Exchange (ETDEWEB)

    Handayani, Gunawan [The Earth Physics and Complex Systems Research Group (Jl. Ganesa 10 Bandung Indonesia) gunawanhandayani@gmail.com (Indonesia)

    2015-04-16

    The signal processing of Ground Penetrating Radar (GPR) requires a certain work flow to obtain good results. Even though the Ground Penetrating Radar data looks similar with seismic reflection data, but the GPR data has particular signatures that the seismic reflection data does not have. This is something to do with coupling between antennae and the ground surface. Because of this, the GPR data should be treated differently from the seismic signal data processing work flow. Even though most of the processing steps still follow the same work flow of seismic reflection data such as: filtering, predictive deconvolution etc. This paper presents the work flow of GPR processing data on rigid pavement measurements. The processing steps start from raw data, de-Wow process, remove DC and continue with the standard process to get rid of noises i.e. filtering process. Some radargram particular features of rigid pavement along with pile foundations are presented.

  6. Work flow of signal processing data of ground penetrating radar case of rigid pavement measurements

    Science.gov (United States)

    Handayani, Gunawan

    2015-04-01

    The signal processing of Ground Penetrating Radar (GPR) requires a certain work flow to obtain good results. Even though the Ground Penetrating Radar data looks similar with seismic reflection data, but the GPR data has particular signatures that the seismic reflection data does not have. This is something to do with coupling between antennae and the ground surface. Because of this, the GPR data should be treated differently from the seismic signal data processing work flow. Even though most of the processing steps still follow the same work flow of seismic reflection data such as: filtering, predictive deconvolution etc. This paper presents the work flow of GPR processing data on rigid pavement measurements. The processing steps start from raw data, de-Wow process, remove DC and continue with the standard process to get rid of noises i.e. filtering process. Some radargram particular features of rigid pavement along with pile foundations are presented.

  7. Multi-Feature Based Multiple Landmine Detection Using Ground Penetration Radar

    OpenAIRE

    Park, S.; K. Kim; Ko, K. H.

    2014-01-01

    This paper presents a novel method for detection of multiple landmines using a ground penetrating radar (GPR). Conventional algorithms mainly focus on detection of a single landmine, which cannot linearly extend to the multiple landmine case. The proposed algorithm is composed of four steps; estimation of the number of multiple objects buried in the ground, isolation of each object, feature extraction and detection of landmines. The number of objects in the GPR signal is estimated by using th...

  8. Feature Extraction and Automatic Material Classification of Underground Objects from Ground Penetrating Radar Data

    OpenAIRE

    Qingqing Lu; Jiexin Pu; Zhonghua Liu

    2014-01-01

    Ground penetrating radar (GPR) is a powerful tool for detecting objects buried underground. However, the interpretation of the acquired signals remains a challenging task since an experienced user is required to manage the entire operation. Particularly difficult is the classification of the material type of underground objects in noisy environment. This paper proposes a new feature extraction method. First, discrete wavelet transform (DWT) transforms A-Scan data and approximation coefficient...

  9. Feature Extraction and Classification of Echo Signal of Ground Penetrating Radar

    Institute of Scientific and Technical Information of China (English)

    ZHOU Hui-lin; TIAN Mao; CHEN Xiao-li

    2005-01-01

    Automatic feature extraction and classification algorithm of echo signal of ground penetrating radar is presented. Dyadic wavelet transform and the average energy of the wavelet coefficients are applied in this paper to decompose and extract feature of the echo signal. Then, the extracted feature vector is fed up to a feed-forward multi-layer perceptron classifier. Experimental results based on the measured GPR echo signals obtained from the Mei-shan railway are presented.

  10. USING GROUND PENETRATING RADAR TO DETERMINE THE TUNNEL LOCATION BURIED UNDER THE GLACIER

    Directory of Open Access Journals (Sweden)

    Deryuga Andrey Mikhaylovich

    2013-09-01

    Full Text Available The works were carried out with the help of ground penetrating radar “Grot-10”. Doublet broadband antennas with the central frequency of 100 MHz were used. Georadar measures the speed of EM waves v in ice-saturated soil and then the value ε′ is calculated. The radargrams received as a result of georadar survey, which represents stacked data (the two-way time is indicated on vertical scale, were transformed into depth sections, which reflect the space structure located below ground. The distance between the bottom landing and buried mountain road near the north tunnel portal is 78,5 m (profile # 1, and the distance from the upper landing is 84,5 m (profile no. 2. Later, in the April 2003 during the hole boring with the diameter 1,2 m the vertical distance between the upper landing, where ground penetrating works were carried out, and the carpet road of the tunnel was calculated. This distance appeared to be 83 m, that means, the discrepancy between boring and georadar data (84,5 m was only 1,5 m. Thus, the results of ground penetrating investigations helped the workers of glacier to make the correct conclusion on time about the location and burial depth of the tunnel.

  11. Coal-mine-hazard detection using in-seam ground-penetrating-radar transillumination. Report of Investigations/1987

    Energy Technology Data Exchange (ETDEWEB)

    Foss, M.M.; Leckenby, R.J.

    1987-01-01

    The Bureau of Mines recently completed peliminary studies to demonstrate the feasibility of using Ground-Penetrating Radar (GPR) for in-seam hazard detection. Investigations included air and coal tests for the purpose of checking equipment accuracy, coal penetration, and other factors such as the effects of receiver orientation. Further investigations involved using both a short pulse and a new prototype synthetic-pulse system to locate a clay vein in a coal seam using transillumination. Data were gathered on multiple travel paths, and a back-projection processing technique was then used to create a tomographic image using the calculated velocities. A computer model of the same coal seam was subsequently processed using the same tomogrpahic technique, and the results were compared with those of the actual data. Results of these preliminary studies show that GPR is feasible for use in in-seam hazard detection and point the direction that future research should take.

  12. Detection capability of a pulsed Ground Penetrating Radar utilizing an oscilloscope and Radargram Fusion Approach for optimal signal quality

    Science.gov (United States)

    Seyfried, Daniel; Schoebel, Joerg

    2015-07-01

    In scientific research pulsed radars often employ a digital oscilloscope as sampling unit. The sensitivity of an oscilloscope is determined in general by means of the number of digits of its analog-to-digital converter and the selected full scale vertical setting, i.e., the maximal voltage range displayed. Furthermore oversampling or averaging of the input signal may increase the effective number of digits, hence the sensitivity. Especially for Ground Penetrating Radar applications high sensitivity of the radar system is demanded since reflection amplitudes of buried objects are strongly attenuated in ground. Hence, in order to achieve high detection capability this parameter is one of the most crucial ones. In this paper we analyze the detection capability of our pulsed radar system utilizing a Rohde & Schwarz RTO 1024 oscilloscope as sampling unit for Ground Penetrating Radar applications, such as detection of pipes and cables in the ground. Also effects of averaging and low-noise amplification of the received signal prior to sampling are investigated by means of an appropriate laboratory setup. To underline our findings we then present real-world radar measurements performed on our GPR test site, where we have buried pipes and cables of different types and materials in different depths. The results illustrate the requirement for proper choice of the settings of the oscilloscope for optimal data recording. However, as we show, displaying both strong signal contributions due to e.g., antenna cross-talk and direct ground bounce reflection as well as weak reflections from objects buried deeper in ground requires opposing trends for the oscilloscope's settings. We therefore present our Radargram Fusion Approach. By means of this approach multiple radargrams recorded in parallel, each with an individual optimized setting for a certain type of contribution, can be fused in an appropriate way in order to finally achieve a single radargram which displays all

  13. Integration of ground-penetrating radar, ultrasonic tests and infrared thermography for the analysis of a precious medieval rose window

    Science.gov (United States)

    Nuzzo, L.; Calia, A.; Liberatore, D.; Masini, N.; Rizzo, E.

    2010-04-01

    The integration of high-resolution, non-invasive geophysical techniques (such as ground-penetrating radar or GPR) with emerging sensing techniques (acoustics, thermography) can complement limited destructive tests to provide a suitable methodology for a multi-scale assessment of the state of preservation, material and construction components of monuments. This paper presents the results of the application of GPR, infrared thermography (IRT) and ultrasonic tests to the 13th century rose window of Troia Cathedral (Apulia, Italy), affected by widespread decay and instability problems caused by the 1731 earthquake and reactivated by recent seismic activity. This integrated approach provided a wide amount of complementary information at different scales, ranging from the sub-centimetre size of the metallic joints between the various architectural elements, narrow fractures and thin mortar fillings, up to the sub-metre scale of the internal masonry structure of the circular ashlar curb linking the rose window to the façade, which was essential to understand the original building technique and to design an effective restoration strategy.

  14. Large-scale, high-definition Ground Penetrating Radar prospection in archaeology

    Science.gov (United States)

    Trinks, I.; Kucera, M.; Hinterleitner, A.; Löcker, K.; Nau, E.; Neubauer, W.; Zitz, T.

    2012-04-01

    The future demands on professional archaeological prospection will be its ability to cover large areas in a time and cost efficient manner with very high spatial resolution and accuracy. The objective of the 2010 in Vienna established Ludwig Boltzmann Institute for Archaeological Prospection and Virtual Archaeology (LBI ArchPro) in collaboration with its eight European partner organisations is the advancement of state-of-the-art archaeological sciences. The application and specific further development of remote sensing, geophysical prospection and virtual reality applications, as well as of novel integrated interpretation approaches dedicated to non-invasive spatial archaeology combining near-surface prospection methods with advanced computer science is crucial for modern archaeology. Within the institute's research programme different areas for distinct case studies in Austria, Germany, Norway, Sweden and the UK have been selected as basis for the development and testing of new concepts for efficient and universally applicable tools for spatial, non-invasive archaeology. In terms of geophysical prospection the investigation of entire archaeological landscapes for the exploration and protection of Europe's buried cultural heritage requires new measurement devices, which are fast, accurate and precise. Therefore the further development of motorized, multichannel survey systems and advanced navigation solutions is required. The use of motorized measurement devices for archaeological prospection implicates several technological and methodological challenges. Latest multichannel Ground Penetrating Radar (GPR) arrays mounted in front off, or towed behind motorized survey vehicles permit large-scale GPR prospection surveys with unprecedented spatial resolution. In particular the motorized 16 channel 400 MHz MALÅ Imaging Radar Array (MIRA) used by the LBI ArchPro in combination with latest automatic data positioning and navigation solutions permits the reliable high

  15. Broadband Ground Penetrating Radar with conformal antennas for subsurface imaging from a rover

    Science.gov (United States)

    Stillman, D. E.; Oden, C. P.; Grimm, R. E.; Ragusa, M.

    2015-12-01

    Ground-Penetrating Radar (GPR) allows subsurface imaging to provide geologic context and will be flown on the next two martian rovers (WISDOM on ExoMars and RIMFAX on Mars 2020). The motivation of our research is to minimize the engineering challenges of mounting a GPR antenna to a spacecraft, while maximizing the scientific capabilities of the GPR. The scientific capabilities increase with the bandwidth as it controls the resolution. Furthermore, ultra-wide bandwidth surveys allow certain mineralogies and rock units to be discriminated based on their frequency-dependent EM or scattering properties. We have designed and field-tested a prototype GPR that utilizes bi-static circularly polarized spiral antennas. Each antenna has a physical size of 61 x 61 x 4 cm, therefore two antennas could be mounted to the underbelly of a MSL-class rover. Spiral antennas were chosen because they have an inherent broadband response and provide a better low frequency response compared with similarly sized linearly polarized antennas. A horizontal spiral radiator emits energy both upward and downward directions. After the radiator is mounted to a metal surface (i.e. the underside of a rover), a cavity is formed that causes the upward traveling energy to reverberate and cause unwanted interference. This interference is minimized by 1) using a high metallization ratio on the spiral to reduce cavity emissions, and 2) placing absorbing material inside the cavity. The resulting antennas provide high gain (0 to 8 dBi) from 200 to 1000 MHz. The low frequency response can be improved by increasing the antenna thickness (i.e., cavity depth). In an initial field test, the antennas were combined with impulse GPR electronics that had ~140 dB of dynamic range (not including antennas) and a sand/clay interface 7 feet deep was detected. To utilize the full bandwidth the antennas, a gated Frequency Modulated Continuous Waveform system will be developed - similar to RIMFAX. The goal is to reach a

  16. State-of-the-art and trends of Ground-Penetrating Radar antenna arrays

    Science.gov (United States)

    Vescovo, Roberto; Pajewski, Lara; Tosti, Fabio

    2016-04-01

    The aim of this contribution is to offer an overview on the antenna arrays for GPR systems, current trends and open issues. Antennas are a critical hardware component of a radar system, dictating its performance in terms of capability to detect targets. Nevertheless, most of the research efforts in the Ground-Penetrating Radar (GPR) area focus on the use of this imaging technique in a plethora of different applications and on the improvement of modelling/inversion/processing techniques, whereas a limited number of studies deal with technological issues related to the design of novel systems, including the synthesis, optimisation and characterisation of advanced antennas. Even fewer are the research activities carried out to develop innovative antenna arrays. GPR antennas operate in a strongly demanding environment and should satisfy a number of requirements, somehow unique and very different than those of conventional radar antennas. The same applies to GPR antenna arrays. The first requirement is an ultra-wide frequency band: the radar has to transmit and receive short-duration time-domain waveforms, in the order of a few nanoseconds, the time-duration of the emitted pulses being a trade-off between the desired radar resolution and penetration depth. Furthermore, GPR antennas should have a linear phase characteristic over the whole operational frequency range, predictable polarisation and gain. Due to the fact that a subsurface imaging system is essentially a short-range radar, the coupling between transmitting and receiving antennas has to be low and short in time. GPR antennas should have quick ring-down characteristics, in order to prevent masking of targets and guarantee a good resolution. The radiation patterns should ensure minimal interference with unwanted objects, usually present in the complex operational environment; to this aim, antennas should provide high directivity and concentrate the electromagnetic energy into a narrow solid angle. As GPR

  17. Getting saturated hydraulic conductivity from surface Ground-Penetrating Radar measurements inside a ring infiltrometer

    Science.gov (United States)

    Leger, E.; Saintenoy, A.; Coquet, Y.

    2013-12-01

    Hydraulic properties of soils, described by the soil water retention and hydraulic conductivity functions, strongly influence water flow in the vadoze zone, as well as the partitioning of precipitation between infiltration into the soil and runoff along the ground surface. Their evaluation has important applications for modelling available water resources and for flood forecasting. It is also crucial to evaluate soil's capacity to retain chemical pollutants and to assess the potential of groundwater pollution. The determination of the parameters involved in soil water retention functions, 5 parameters when using the van Genuchten function, is usually done by laboratory experiments, such as the water hanging column. Hydraulic conductivity, on the other hand can be estimated either in laboratory, or in situ using infiltrometry tests. Among the large panel of existing tests, the single or double ring infiltrometers give the field saturated hydraulic conductivity by applying a positive charge on soils, whereas the disk infiltrometer allows to reconstruct the whole hydraulic conductivity curve, by applying different charges smaller than or equal to zero. In their classical use, volume of infiltrated water versus time are fitted to infer soil's hydraulic conductivity close to water saturation. Those tests are time-consuming and difficult to apply to landscape-scale forecasting of infiltration. Furthermore they involve many assumptions concerning the form of the infiltration bulb and its evolution. Ground-Penetrating Radar (GPR) is a geophysical method based on electromagnetic wave propagation. It is highly sensitive to water content variations directly related to the dielectric permittivity. In this study GPR was used to monitor water infiltration inside a ring infiltrometer and retrieve the saturated hydraulic conductivity. We carried out experiments in a quarry of Fontainebleau sand, using a Mala RAMAC system with antennae centered on 1600 MHz. We recorded traces at

  18. Ice thickness profile surveying with ground penetrating radar at Artesonraju Glacier, Peru

    Science.gov (United States)

    Chisolm, Rachel; Rabatel, Antoine; McKinney, Daene; Condom, Thomas; Cochacin, Alejo; Davila Roller, Luzmilla

    2014-05-01

    Tropical glaciers are an essential component of the water resource systems in the mountainous regions where they are located, and a warming climate has resulted in the accelerated retreat of Andean glaciers in recent decades. The shrinkage of Andean glaciers influences the flood risk for communities living downstream as new glacial lakes have begun to form at the termini of some glaciers. As these lakes continue to grow in area and volume, they pose an increasing risk of glacial lake outburst floods (GLOFs). Ice thickness measurements have been a key missing link in studying the tropical glaciers in Peru and how climate change is likely to impact glacial melt and the growth of glacial lakes. Ground penetrating radar (GPR) has rarely been applied to glaciers in Peru to measure ice thickness, and these measurements can tell us a lot about how a warming climate will affect glaciers in terms of thickness changes. In the upper Paron Valley (Cordillera Blanca, Peru), an emerging lake has begun to form at the terminus of the Artesonraju Glacier, and this lake has key features, including overhanging ice and loose rock likely to create slides, that could trigger a catastrophic GLOF if the lake continues to grow. Because the glacier mass balance and lake mass balance are closely linked, ice thickness measurements and measurements of the bed slope of the Artesonraju Glacier and underlying bedrock can give us an idea of how the lake is likely to evolve in the coming decades. This study presents GPR data taken in July 2013 at the Artesonraju Glacier as part of a collaboration between the Unidad de Glaciologia y Recursos Hidricos (UGRH) of Peru, the Institut de Recherche pour le Développement (IRD) of France and the University of Texas at Austin (UT) of the United States of America. Two different GPR units belonging to UGRH and UT were used for subsurface imaging to create ice thickness profiles and to characterize the total volume of ice in the glacier. A common midpoint

  19. Testing sea-level markers observed in ground-penetrating radar data from Feddet, south-eastern Denmark

    DEFF Research Database (Denmark)

    Hede, Mikkel Ulfeldt; Nielsen, Lars; Clemmensen, Lars B;

    2012-01-01

    Ground-penetrating radar (GPR) data have been collected across the modern part (test identification of sea-level markers in GPR data from microtidal depositional environments. Nielsen and Clemmensen (2009) showed...

  20. Acoustic Communications Measurement Systems (ACOMMS)

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Design and develop adaptive signal processing techniques to improve underwater acoustic communications and networking. Phase coherent and incoherent signal...

  1. Civil Engineering Applications of Ground Penetrating Radar: Research Perspectives in COST Action TU1208

    Science.gov (United States)

    Pajewski, Lara; Benedetto, Andrea; Loizos, Andreas; Slob, Evert; Tosti, Fabio

    2013-04-01

    can be used by GPR operators to identify the signatures generated by uncommon targets or by composite structures. Repeated evaluations of the electromagnetic field scattered by known targets can be performed by a forward solver, in order to estimate - through comparison with measured data - the physics and geometry of the region investigated by the GPR. It is possible to identify three main areas, in the GPR field, that have to be addressed in order to promote the use of this technology in the civil engineering. These are: a) increase of the system sensitivity to enable the usability in a wider range of conditions; b) research novel data processing algorithms/analysis tools for the interpretation of GPR results; c) contribute to the development of new standards and guidelines and to training of end users, that will also help to increase the awareness of operators. In this framework, the COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar", proposed by Lara Pajewski, "Roma Tre" University, Rome, Italy, has been approved in November 2012 and is going to start in April 2013. It is a 4-years ambitious project already involving 17 European Countries (AT, BE, CH, CZ, DE, EL, ES, FI, FR, HR, IT, NL, NO, PL, PT, TR, UK), as well as Australia and U.S.A. The project will be developed within the frame of a unique approach based on the integrated contribution of University researchers, software developers, geophysics experts, Non-Destructive Testing equipment designers and producers, end users from private companies and public agencies. The main objective of the COST Action TU1208 is to exchange and increase scientific-technical knowledge and experience of GPR techniques in civil engineering, whilst promoting the effective use of this safe and non-destructive technique in the monitoring of systems. In this interdisciplinary Action, advantages and limitations of GPR will be highlighted, leading to the identification of gaps in knowledge and technology

  2. Mapping of permafrost surface using ground-penetrating radar at Kangerlussuaq Airport, western Greenland

    DEFF Research Database (Denmark)

    Jørgensen, Anders Stuhr; Andreasen, Frank

    2007-01-01

    Kangerlussuaq Airport is located at 67°N and 51°W in the zone of continuous permafrost in western Greenland. Its proximity to the Greenlandic ice sheet results in a dry sub-arctic climate with a mean annual temperature of −5.7 °C. The airport is built on a river terrace mostly consisting of fluvial...... deposits overlying fine-grained marine melt-water sediments and bedrock. A ground-penetrating radar (GPR) survey was performed to study the frozen surface beneath the airfield. The measurements were carried out in late July 2005 on the southern parking area in Kangerlussuaq Airport. Five years earlier...

  3. Quantifying snow and vegetation interactions in the high arctic based on ground penetrating radar (GPR)

    DEFF Research Database (Denmark)

    Gacitúa, G.; Bay, C.; Tamstorf, M.

    2013-01-01

    The quantification of the relationship between accumulation of snow and vegetation is crucial for understanding the influence of vegetation dynamics. We here present an analysis of the thickness of the snow and hydrological availability in relation to the seven main vegetation types in the High...... Arctic in Northeast Greenland. We used ground penetrating radar (GPR) for snow thickness measurements across the Zackenberg valley. Measurements were integrated to the physical conditions that support the vegetation distribution. Descriptive statistics and correlations of the distribution of each...

  4. Embedding the multiple instance problem: applications to landmine detection with ground penetrating radar

    Science.gov (United States)

    Bolton, Jeremy; Gader, Paul; Frigui, Hichem

    2013-06-01

    Multiple Instance Learning is a recently researched learning paradigm in machine intelligence which operates under conditions of uncertainty with the cost of increased computational burden. This increase in computational burden can be avoided by embedding these so-called multiple instances using a kernel function or other embedding function. In the following, a family of fast multiple instance relevance vector machines are used to learn and classify landmine signatures in ground penetrating radar data. Results indicate a significant reduction in computational complexity without a loss in classification accuracy in operating conditions.

  5. The SIMCA algorithm for processing Ground Penetrating Radar data and its use in landmine detection

    OpenAIRE

    Sengodan, A.; Cockshott, W. P.

    2012-01-01

    The main challenge of ground penetrating radar (GPR)\\ud based land mine detection is to have an accurate image\\ud analysis method that is capable of reducing false alarms.\\ud However an accurate image relies on having sufficient spatial\\ud resolution in the received signal. But because the diameter\\ud of an AP mine can be as low as 2cm and many soils\\ud have very high attenuations at frequencies above 3GHz,\\ud the accurate detection of landmines is accomplished using\\ud advanced algorithms. U...

  6. Context-dependent feature selection for landmine detection with ground-penetrating radar

    Science.gov (United States)

    Ratto, Christopher R.; Torrione, Peter A.; Collins, Leslie M.

    2009-05-01

    We present a novel method for improving landmine detection with ground-penetrating radar (GPR) by utilizing a priori knowledge of environmental conditions to facilitate algorithm training. The goal of Context-Dependent Feature Selection (CDFS) is to mitigate performance degradation caused by environmental factors. CDFS operates on GPR data by first identifying its environmental context, and then fuses the decisions of several classifiers trained on context-dependent subsets of features. CDFS was evaluated on GPR data collected at several distinct sites under a variety of weather conditions. Results show that using prior environmental knowledge in this fashion has the potential to improve landmine detection.

  7. A review of selected ground penetrating radar applications to mineral resource evaluations

    Science.gov (United States)

    Francke, Jan

    2012-06-01

    Since the commercialisation of ground penetrating radar (GPR) in the 1970s, the technology has been relegated to niche applications in the mining industry. Advances in radar technology, such as flexible collinear antennas and the integration of live differential GPS positioning, have spurred GPR's acceptance in recent years as a standard exploration method for a number of deposit types. Provided herein is an overview of commercialised GPR applications for surface mineral resource evaluations, covering examples of alluvial channels, nickel and bauxitic laterites, iron ore deposits, mineral sands, coal and kimberlites.

  8. Ground-penetrating radar signal processing for the detection of buried objects

    Science.gov (United States)

    Walters, Mitchell; Garcia, Ephrahim

    2011-06-01

    In this work the singular value decomposition (SVD) is used to analyze matrices of ground penetrating radar (GPR) data. The targets to be detected are Russian PMN antipersonnel landmines and improvised explosive devices constructed from 155mm artillery shells. Target responses are simulated with GPRmax 2D, a simulation package based on the Finite- Difference-Time-Domain method. First, the utility of the SVD for image enhancement and reconstruction is demonstrated. Then the singular values and singular vectors of the decomposed matrices are analyzed with the goal of finding properties that will aid in the development of automated underground detection algorithms.

  9. Computerized acoustical characterization system of medical phantoms

    Science.gov (United States)

    Nazihah, M. D.; Kadri, S.; Yaacob, M. I. H.; Rosly, J.

    2013-05-01

    The development of a computerized acoustical characterization system of medical phantoms is described in this paper. The system employs the insertion technique and it was developed using LabView 2011 where the ultrasound signal was acquired through the interfacing scheme of an oscilloscope to a personal computer. The system performance was validated by comparing measured acoustical properties with values obtained from the previous studies. Other than faster measurement time, the developed system carried percentage difference at less than 1.00% for all of the acoustical properties measurements at 23.0°C to 25.0°C respectively.

  10. COST Action TU1208 - Working Group 1 - Design and realisation of Ground Penetrating Radar equipment for civil engineering applications

    Science.gov (United States)

    Pajewski, Lara; Benedetto, Andrea; D'Amico, Sebastiano; Ferrara, Vincenzo; Frezza, Fabrizio; Persico, Raffaele; Tosti, Fabio

    2017-04-01

    This work aims at presenting the main results achieved by Working Group (WG) 1 "Novel Ground Penetrating Radar instrumentation" of the COST (European COoperation in Science and Technology) Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar" (www.cost.eu, www.GPRadar.eu). The principal goal of the Action, which started in April 2013 and is ending in October 2017, is to exchange and increase scientific-technical knowledge and experience of Ground Penetrating Radar techniques in civil engineering, whilst promoting throughout Europe the effective use of this safe non-destructive technique. The Action involves more than 300 Members from 28 COST Countries, a Cooperating State, 6 Near Neighbour Countries and 6 International Partner Countries. The most interesting achievements of WG1 include: 1. The state of the art on GPR systems and antennas was composed; merits and limits of current GPR systems in civil engineering applications were highlighted and open issues were identified. 2. The Action investigated the new challenge of inferring mechanical (strength and deformation) properties of flexible pavement from electromagnetic data. A semi-empirical method was developed by an Italian research team and tested over an Italian test site: a good agreement was found between the values measured by using a light falling weight deflectometer (LFWD) and the values estimated by using the proposed semi-empirical method, thereby showing great promises for large-scale mechanical inspections of pavements using GPR. Subsequently, the method was tested on a real scale, on an Italian road in the countryside: again, a good agreement between LFWD and GPR data was achieved. As a third step, the method was tested at larger scale, over three different road sections within the districts of Madrid and Guadalajara, in Spain: GPR surveys were carried out at the speed of traffic for a total of 39 kilometers, approximately; results were collected by using different GPR antennas

  11. Acoustically-driven microfluidic systems

    Energy Technology Data Exchange (ETDEWEB)

    Wang, A W; Benett, W J; Tarte, L R

    2000-06-23

    We have demonstrated a non-contact method of concentrating and mixing particles in a plastic microfluidic chamber employing acoustic radiation pressure. A flaw cell package has also been designed that integrates liquid sample interconnects, electrical contacts and a removable sample chamber. Experiments were performed on 1, 3, 6, and 10 {micro}m polystyrene beads. Increased antibody binding to a solid-phase substrate was observed in the presence of acoustic mixing due to improve mass transport.

  12. Evaluation of 3D Ground Penetrating Radar Efficiency for Abandoned Tailings Pond Internal Structure Analysis and Risk Assessment

    Science.gov (United States)

    Cortada, Unai; Martínez, Julián; Hidalgo, Mª Carmen; Rey, Javier

    2017-04-01

    Evaluation of 3D Ground Penetrating Radar Efficiency for Abandoned Tailings Pond Internal Structure Analysis and Risk Assessment Abandoned tailings ponds constitute a severe environmental problem in old Pb mining districts due to their high contents in metallic and semi-metallic elements. In most of the cases, there is a lack of information about the construction procedures and the previous environmental situation, which hinders the environmental risk evaluation. In these cases, Ground Penetrating Radar (GPR) could be an interesting technique to analyze the internal structure of the tailings ponds and detect vulnerable zones for leaching processes. Consequently, the GPR could help in the abandoned tailings ponds environmental risk assessment. In this study, a GPR 3D campaign was carried out with a 250 MHz frequency antenna in order to evaluate the efficiency of this technique in both the analysis of internal structures and the environmental risk assessment. Subsequently, 2D and 3D models were undertaken to represent graphically the obtained results. The studied tailings pond is located in the Guadiel river bank, a water course draining the mining district of Linares, Spain. The dam is 150 m length and 80 m width. The GPR 3D was done in a selected area near the central part of the pond. The analyzed grid was 25x50 m and the spacing of the slides was 1 m. The study revealed that the contact between the tailings and the substratum is located at 2.5 m. No intermediate layer was found, which means that the tailings pond was heightened on the fluvial terrace without any insulation system. Inside the first meter of the pond, a cross stratification was identified. The orientation of those laminations changed with the depth, which means that the stockpiling was performed from the different sides of the tailings pond. Furthermore, the direction of these stratifications is slightly concentric to the middle of the dam which could be associated with a central drainage system

  13. Real-Time Landmine Detection with Ground-Penetrating Radar Using Discriminative and Adaptive Hidden Markov Models

    Directory of Open Access Journals (Sweden)

    Paul Gader

    2005-07-01

    Full Text Available We propose a real-time software system for landmine detection using ground-penetrating radar (GPR. The system includes an efficient and adaptive preprocessing component; a hidden Markov model- (HMM- based detector; a corrective training component; and an incremental update of the background model. The preprocessing is based on frequency-domain processing and performs ground-level alignment and background removal. The HMM detector is an improvement of a previously proposed system (baseline. It includes additional pre- and postprocessing steps to improve the time efficiency and enable real-time application. The corrective training component is used to adjust the initial model parameters to minimize the number of misclassification sequences. This component could be used offline, or online through feedback to adapt an initial model to specific sites and environments. The background update component adjusts the parameters of the background model to adapt it to each lane during testing. The proposed software system is applied to data acquired from three outdoor test sites at different geographic locations, using a state-of-the-art array GPR prototype. The first collection was used as training, and the other two (contain data from more than 1200 m2 of simulated dirt and gravel roads for testing. Our results indicate that, on average, the corrective training can improve the performance by about 10% for each site. For individual lanes, the performance gain can reach 50%.

  14. Through the looking glass: Applications of ground-penetrating radar in archaeology

    Science.gov (United States)

    Stamos, Antonia

    The focus of this dissertation is to present the results of four years' worth of geophysical surveying at four major archaeological sites in Greece and the benefits to the archaeological community. The ground penetrating radar offers an inexpensive, non-destructive solution to the problem of deciding how much of a site is worth excavating and which areas would yield the most promising results. An introduction to the ground penetrating radar, or GPR, the equipment necessary to conduct a geophysical survey in the field, and the methods of data collection and subsequent data processing are all addressed. The benefits to the archeological community are many, and future excavations will incorporate such an important tool for a greater understanding of the site. The history of GPR work in the archaeological field has grown at an astounding rate from its beginnings as a simple tool for petroleum and mining services in the beginning of the twentieth century. By mid-century, the GPR was first applied to archaeological sites rather than its common use by utility companies in locating pipes, cables, tunnels, and shafts. Although the preliminary surveys were little more than a search to locate buried walls, the success of these initial surveys paved the ground for future surveys at other archaeological sites, many testing the radar's efficacy with a myriad of soil conditions and properties. The four sites in which geophysical surveys with a ground penetrating radar were conducted are Azorias on the island of Crete, Kolonna on the island of Aegina, Mochlos Island and Coastal Mochlos on the island of Crete, and Mycenae in the Peloponnese on mainland Greece. These case studies are first presented in terms of their geographical location, their mythology and etymology, where applicable, along with a brief history of excavation and occupation of the site. Additional survey methods were used at Mycenae, including aerial photography and ERDAS Imagine, a silo locating program now

  15. Acoustic Test Characterization of Melamine Foam for Usage in NASA's Payload Fairing Acoustic Attenuation Systems

    Science.gov (United States)

    Hughes, William O.; McNelis, Anne M.; McNelis, Mark E.

    2014-01-01

    The external acoustic liftoff levels predicted for NASA's future heavy lift launch vehicles are expected to be significantly higher than the environment created by today's commercial launch vehicles. This creates a need to develop an improved acoustic attenuation system for future NASA payload fairings. NASA Glenn Research Center initiated an acoustic test series to characterize the acoustic performance of melamine foam, with and without various acoustic enhancements. This testing was denoted as NEMFAT, which stands for NESC Enhanced Melamine Foam Acoustic Test, and is the subject of this paper. Both absorption and transmission loss testing of numerous foam configurations were performed at the Riverbank Acoustical Laboratory in July 2013. The NEMFAT test data provides an initial acoustic characterization and database of melamine foam for NASA. Because of its acoustic performance and lighter mass relative to fiberglass blankets, melamine foam is being strongly considered for use in the acoustic attenuation systems of NASA's future launch vehicles.

  16. Development of the seafloor acoustic ranging system

    Science.gov (United States)

    Osada, Y.; Kido, M.; Fujimoto, H.

    2007-12-01

    We have developed a seafloor acoustic ranging system, which simulates an operation with the DONET (Development of Dense Ocean-floor Network System for Earthquake and Tsunami) cable, to monitor seafloor crustal movement. The seafloor acoustic ranging system was based on the precise acoustic transponder (PXP). We have a few problems for the improvement of the resolution. One thing is the variation of sound speed. Another is the bending of ray path. A PXP measures horizontal distances on the seafloor from the round trip travel times of acoustic pulses between pairs of PXP. The PXP was equipped with the pressure, temperature gauge and tilt-meter. The variation of sound speed in seawater has a direct effect on the measurement. Therefore we collect the data of temperature and pressure. But we don't collect the data of salinity because of less influence than temperature and pressure. Accordingly a ray path of acoustic wave tends to be bent upward in the deep sea due to the Snell's law. As the acoustic transducer of each PXPs held about 3.0m above the seafloor, the baseline is too long for altitude from the seafloor. In this year we carried out the experiment for the seafloor acoustic ranging system. We deployed two PXPs at about 750m spacing on Kumano-nada. The water depth is about 2050m. We collected the 660 data in this experiment during one day. The round trip travel time show the variation with peak-to-peak amplitude of about 0.03msec. It was confirmed to explain the majority in this change by the change in sound speed according to the temperature and pressure. This results shows the resolution of acoustic measurements is +/-2mm. Acknowledgement This study is supported by 'DONET' of Ministry of Education, Culture, Sports, Science and Technology.

  17. 3D Ground Penetrating Radar to Detect Tree Roots and Estimate Root Biomass in the Field

    Directory of Open Access Journals (Sweden)

    Shiping Zhu

    2014-06-01

    Full Text Available The objectives of this study were to detect coarse tree root and to estimate root biomass in the field by using an advanced 3D Ground Penetrating Radar (3D GPR system. This study obtained full-resolution 3D imaging results of tree root system using 500 MHz and 800 MHz bow-tie antennas, respectively. The measurement site included two larch trees, and one of them was excavated after GPR measurements. In this paper, a searching algorithm, based on the continuity of pixel intensity along the root in 3D space, is proposed, and two coarse roots whose diameters are more than 5 cm were detected and delineated correctly. Based on the detection results and the measured root biomass, a linear regression model is proposed to estimate the total root biomass in different depth ranges, and the total error was less than 10%. Additionally, based on the detected root samples, a new index named “magnitude width” is proposed to estimate the root diameter that has good correlation with root diameter compared with other common GPR indexes. This index also provides direct measurement of the root diameter with 13%–16% error, providing reasonable and practical root diameter estimation especially in the field.

  18. Application of ground-penetrating radar at McMurdo Station, Antarctica

    Energy Technology Data Exchange (ETDEWEB)

    Stefano, J.E.

    1992-01-01

    Argonne National Laboratory initiated a site investigation program at McMurdo Station, Antarctica, to characterize environmental contamination. The performance and usefulness of ground-penetrating radar (GPR) was evaluated under antarctic conditions during the initial site investigation in January 1991. Preliminary surveys were successful in defining the contact between reworked pyroclastic material and in the prefill, undisturbed pyroclastics and basalts at some sites. Interference from radio traffic at McMurdo Station was not observed, but interference was a problem in work with unshielded antennas near buildings. In general, the results of this field test suggest that high-quality, high-resolution, continuous subsurface profiles can be produced with GPR over most of McMurdo Station.

  19. Application of ground-penetrating radar at McMurdo Station, Antarctica

    Energy Technology Data Exchange (ETDEWEB)

    Stefano, J.E.

    1992-05-01

    Argonne National Laboratory initiated a site investigation program at McMurdo Station, Antarctica, to characterize environmental contamination. The performance and usefulness of ground-penetrating radar (GPR) was evaluated under antarctic conditions during the initial site investigation in January 1991. Preliminary surveys were successful in defining the contact between reworked pyroclastic material and in the prefill, undisturbed pyroclastics and basalts at some sites. Interference from radio traffic at McMurdo Station was not observed, but interference was a problem in work with unshielded antennas near buildings. In general, the results of this field test suggest that high-quality, high-resolution, continuous subsurface profiles can be produced with GPR over most of McMurdo Station.

  20. Non-destructive evaluation of moisture content in wood using ground-penetrating radar

    Science.gov (United States)

    Reci, Hamza; Chinh Maï, Tien; Sbartaï, Zoubir Mehdi; Pajewski, Lara; Kiri, Emanuela

    2016-12-01

    This paper presents the results of a series of laboratory measurements, carried out to study how the ground-penetrating radar (GPR) signal is affected by moisture variation in wood material. The effects of the wood fibre direction, with respect to the polarisation of the electromagnetic field, are investigated. The relative permittivity of wood and the amplitude of the electric field received by the radar are measured for different humidity levels using the direct-wave method in wide angle radar reflection configuration, in which one GPR antenna is moved while the other is kept in a fixed position. The received signal is recorded for different separations between the transmitting and receiving antennas. Dielectric constants estimated from direct waves are compared to those estimated from reflected waves: direct and reflected waves show different behaviour when the moisture content varies, due to their different propagation paths.

  1. Comparative analysis of clutter suppression techniques for landmine detection using ground-penetrating radar

    Science.gov (United States)

    Yoldemir, Ahmet Burak; Gürcan, Rıdvan; Kaplan, Gülay Büyükaksoy; Sezgin, Mehmet

    2011-06-01

    In this study, we provide an extensive comparison of different clutter suppression techniques that are proposed to enhance ground penetrating radar (GPR) data. Unlike previous studies, we directly measure and present the effect of these preprocessing algorithms on the detection performance. Basic linear prediction algorithm is selected as the detection scheme and it is applied to real GPR data after applying each of the available clutter suppression techniques. All methods are tested on an extensive data set of different surrogate mines and other objects that are commonly encountered under the ground. Among several algorithms, singular value decomposition based clutter suppression stands out with its superior performance and low computational cost, which makes it practical to use in real-time applications.

  2. Urban soil exploration through multi-receiver electromagnetic induction and stepped-frequency ground penetrating radar.

    Science.gov (United States)

    Van De Vijver, Ellen; Van Meirvenne, Marc; Vandenhaute, Laura; Delefortrie, Samuël; De Smedt, Philippe; Saey, Timothy; Seuntjens, Piet

    2015-07-01

    In environmental assessments, the characterization of urban soils relies heavily on invasive investigation, which is often insufficient to capture their full spatial heterogeneity. Non-invasive geophysical techniques enable rapid collection of high-resolution data and provide a cost-effective alternative to investigate soil in a spatially comprehensive way. This paper presents the results of combining multi-receiver electromagnetic induction and stepped-frequency ground penetrating radar to characterize a former garage site contaminated with petroleum hydrocarbons. The sensor combination showed the ability to identify and accurately locate building remains and a high-density soil layer, thus demonstrating the high potential to investigate anthropogenic disturbances of physical nature. In addition, a correspondence was found between an area of lower electrical conductivity and elevated concentrations of petroleum hydrocarbons, suggesting the potential to detect specific chemical disturbances. We conclude that the sensor combination provides valuable information for preliminary assessment of urban soils.

  3. Estimating Saturated Hydraulic Conductivity from Surface Ground-Penetrating Radar Monitoring of Infiltration

    CERN Document Server

    Léger, Emmanuel; Coquet, Yves

    2013-01-01

    In this study we used Hydrus-1D to simulate water infiltration from a ring infiltrometer. We generated water content profiles at each time step of infiltration, based on a particular value of the saturated hydraulic conductivity while knowing the other van Genuchten parameters. Water content profiles were converted to dielectric permittivity profiles using the Complex Refractive Index Method relation. We then used the GprMax suite of programs to generate radargrams and to follow the wetting front using arrival time of electromagnetic waves recorded by a Ground-Penetrating Radar (GPR). Theoretically, the depth of the inflection point of the water content profile simulated at any infiltration time step is related to the peak of the reflected amplitude recorded in the corresponding trace in the radargram. We used this relationship to invert the saturated hydraulic conductivity for constant and falling head infiltrations. We present our method on synthetic examples and on two experiments carried out on sand. We f...

  4. Multi-Feature Based Multiple Landmine Detection Using Ground Penetration Radar

    Directory of Open Access Journals (Sweden)

    S. Park

    2014-06-01

    Full Text Available This paper presents a novel method for detection of multiple landmines using a ground penetrating radar (GPR. Conventional algorithms mainly focus on detection of a single landmine, which cannot linearly extend to the multiple landmine case. The proposed algorithm is composed of four steps; estimation of the number of multiple objects buried in the ground, isolation of each object, feature extraction and detection of landmines. The number of objects in the GPR signal is estimated by using the energy projection method. Then signals for the objects are extracted by using the symmetry filtering method. Each signal is then processed for features, which are given as input to the support vector machine (SVM for landmine detection. Three landmines buried in various ground conditions are considered for the test of the proposed method. They demonstrate that the proposed method can successfully detect multiple landmines.

  5. Detection of explosive hazards using spectrum features from forward-looking ground penetrating radar imagery

    Science.gov (United States)

    Farrell, Justin; Havens, Timothy C.; Ho, K. C.; Keller, James M.; Ton, Tuan T.; Wong, David C.; Soumekh, Mehrdad

    2011-06-01

    Buried explosives have proven to be a challenging problem for which ground penetrating radar (GPR) has shown to be effective. This paper discusses an explosive hazard detection algorithm for forward looking GPR (FLGPR). The proposed algorithm uses the fast Fourier transform (FFT) to obtain spectral features of anomalies in the FLGPR imagery. Results show that the spectral characteristics of explosive hazards differ from that of background clutter and are useful for rejecting false alarms (FAs). A genetic algorithm (GA) is developed in order to select a subset of spectral features to produce a more generalized classifier. Furthermore, a GA-based K-Nearest Neighbor probability density estimator is employed in which targets and false alarms are used as training data to produce a two-class classifier. The experimental results of this paper use data collected by the US Army and show the effectiveness of spectrum based features in the detection of explosive hazards.

  6. Magnetometry and Ground-Penetrating Radar Studies in the Sihuas Valley, Peru

    Science.gov (United States)

    Wisnicki, E.; Papadimitrios, K.; Bank, C.

    2013-12-01

    The Quillcapampa la Antigua site in Peru's Sihuas Valley is a settlement from Peru's Middle Horizon (600-100 A.D.). Archaeological interest in the area stems from the question of whether ancient civilizations were able to have extensive state control of distant groups, or whether state influence occurred through less direct ties (e.g., marriage, religion, or trade). Our geophysical surveys are preliminary to archaeological digging in the area. Ground-penetrating radar and magnetometry attempt to locate areas of interest for focused archaeological excavation, characterize the design of architectural remains and burial mounds in the area, and allow archaeologists to interpret the amount of influence the Wari civilization had on the local residents.

  7. Detection of underground voids in Tahura Japan Cave Bandung using ground penetrating radar

    Science.gov (United States)

    Azimmah, Azizatun; Widodo

    2017-07-01

    The detection of underground voids is important due to their effects on subsidence higher risk. Ground Penetrating Radar is one of geophysical electromagnetic methods that has been proven to be able to detect and locate any void beneath the surface effectively at a shallow depth. This method uses the contrasts of dielectric properties, resistivity and magnetic permeability to investigate and map what lies beneath the surface. Hence, this research focused on how GPR could be applied for detecting underground voids at the site of investigation, The Japan Cave in Taman Hutan Raya located in Dago, Bandung, Indonesia. A 100 MHz GPR shielded antenna frequency were used to measure three >80 meters long measurement lines. These three GPR profiles were positioned on the surface above the Japan Cave. The radargram results showed existences of different amplitude regions proven to be the air-filled cavities, at a depth of <10 meters, and interfaces between the underneath layers.

  8. Sequential feature selection for detecting buried objects using forward looking ground penetrating radar

    Science.gov (United States)

    Shaw, Darren; Stone, Kevin; Ho, K. C.; Keller, James M.; Luke, Robert H.; Burns, Brian P.

    2016-05-01

    Forward looking ground penetrating radar (FLGPR) has the benefit of detecting objects at a significant standoff distance. The FLGPR signal is radiated over a large surface area and the radar signal return is often weak. Improving detection, especially for buried in road targets, while maintaining an acceptable false alarm rate remains to be a challenging task. Various kinds of features have been developed over the years to increase the FLGPR detection performance. This paper focuses on investigating the use of as many features as possible for detecting buried targets and uses the sequential feature selection technique to automatically choose the features that contribute most for improving performance. Experimental results using data collected at a government test site are presented.

  9. Ground-penetrating radar study of the Rahivere peat bog, eastern Estonia

    Directory of Open Access Journals (Sweden)

    Jüri Plado

    2011-03-01

    Full Text Available The current case study presents results of the ground-penetrating radar (GPR profiling at one of the Saadjärve drumlin field interstitial troughs, the Rahivere bog, eastern Estonia. The study was conducted in order to identify the bog morphology, and the thickness and geometry of the peat body. The method was also used to describe the applicability of GPR in the evaluation of the peat deposit reserve as the Rahivere bog belongs among the officially registered peat reserves. Fourteen GPR profiles, ~ 100 m apart and oriented perpendicular to the long axis of the depression, covering the bog and its surrounding areas, were acquired. In order to verify the radar image interpretation as well as to evaluate the velocity of electromagnetic waves in peat, a common source configuration was utilized and thirteen boreholes were drilled on the GPR profiles. A mean value of 0.036 m ns–1 corresponding to relative dielectric permittivity of 69.7 was used for the time–depth conversion. Radar images reveal major reflection from the peat–soil interface up to a depth of about 4 m, whereas drillings showed a maximum thickness of 4.5 m of peat. Minor reflections appear from the upper peat and mineral soil. According to the borehole data, undecomposed peat is underlain by decomposed one, but identifying them by GPR is complicated. Mineral soil consists of glaciolimnic silty sand in the peripheral areas of the trough, overlain by limnic clay in the central part. The calculated peat volumes (1 200 000 m3 were found to exceed the earlier estimation (979 000 m3 that was based solely on drilling data. Ground-penetrating radar, as a method that allows mapping horizontal continuity of the sub-peat interface in a non-destructive way, was found to provide detailed information for evaluating peat depth and extent.

  10. Application of Markov random fields to landmine detection in ground penetrating radar data

    Science.gov (United States)

    Torrione, Peter A.; Collins, Leslie

    2008-04-01

    Recent advances in ground penetrating radar (GPR) design and fabrication have resulted in improved fidelity responses from relatively small, shallow-buried objects like landmines and improvised explosive devices. As the responses measured with GPR improve, more and more advanced processing techniques can be brought to bear on the problem of target identification in GPR data. From an electromagnetic point of view, the problem of target detection in GPR signal processing is reducible to inferring the presence or absence of changes in the electromagnetic properties of soils and thus the presence or absence of buried targets. Problems arise because the algorithms required for the full electromagnetic inversion of GPR signals are extremely computationally expensive, and usually rely on assumptions of electromagnetically constant transmission media; these problems typically make the real-time implementation of purely electromagnetic-inspired algorithms infeasible. On the other hand, purely statistical or signal-processing inspired approaches to target identification in GPR often lack a solid theoretical basis in the underlying physics, which is fundamental to understanding responses in GPR. In this work, we propose a model for responses in time-domain ground penetrating radar that attempts to incorporate the underlying physics of the problem, but avoids several of the issues inherent in assuming constant media with known electrical parameters by imposing a statistical model over the observed parameters of interest in A-scans - namely the signal gains, times of arrival, etc. The spatial requirements of the proposed statistical model suggests the application of Markov random field (MRF) distributions which provide expressive, but computationally simple models of spatial interactions. In this work we will explore the application of physics-based MRF's as generative models for time-domain GPR data, the pre-screening algorithms that this model motivates, and discuss how the

  11. GROUND PENETRATING RADAR INVESTIGATIONS FOR ARCHITECTURAL HERITAGE PRESERVATION OF THE HABIB SAKAKINI PALACE, CAIRO, EGYPT

    Directory of Open Access Journals (Sweden)

    Sayed HEMEDA

    2012-09-01

    Full Text Available The modern architectural heritage of Egypt is both varied and vast. It covers all nonecclesiastical buildings, important monumental structures (mansions, municipal buildings in the history of architecture, as well as more common buildings. They include houses (from mansions to simple dwellings, public buildings (schools, administrative buildings, hospitals, industrial buildings (factories, warehouses, mills, bridges, monastic dependencies (drinking foundations, gardens and any other modern structures that fall within the category of monuments and comprise the Egyptian cultural heritage. We present herein a comprehensive Ground Penetration Radar (GPR investigation and hazard assessment for the rehabilitation and strengthening of Habib Sakakini’s Palace, in Cairo, considered one of the most significant architectural heritage sites in Egypt. The palace is located on an ancient water pond at the eastern side of the Egyptian gulf, beside the Sultan Bebris Al-Bondoqdary mosque, a place also called “Prince Qraja al-Turkumany pond”. That pond was drained by Habib Sakakini in 1892, to construct his famous palace in 1897. Eight hundred meters of Ground Penetration Radar (GPR profiling were conducted, to monitor the subsurface conditions. 600 meters were made in the surrounding area of the Palace and 200 m at the basement. The aim was to monitor the soil conditions beneath and around the Palace and to identify potential geological discontinuities, or the presence of faults and cavities. A suitable single and dual antenna were used (500-100 MHZ to penetrate to the desired depth of 7 meters (ASTM D6432. The GPR was also used to detect the underground water. At the building basement the GPR was used to identify the foundation thickness and the soil - basement interface, as well as for the inspection of cracks in some supporting columns, piers and masonry walls. All the results, together with the seismic hazard analysis, will be used for a complete

  12. The Use of Ground Penetrating Radar for Mapping Rock Stratigraphy and Tectonics:Implications for Geotechnical Engineering

    Institute of Scientific and Technical Information of China (English)

    Awni TBatayneh; Taisser Zumlot; Habes Ghrefat; Mahmud MEl-Waheidi; Yousef Nazzal

    2014-01-01

    This paper presents results from ground penetrating radar surveys using the SIR-10B GPR instrument (manufactured by Geophysical Survey System Inc., USA), with 400 MHz monostatic antenna (model 5 103). Survey was made over 3 excavation levels along the highway section at the Ras en Naqab escarpment area, Southwest Jordan. A total of 217 m along 4 profiles were covered in the winter of 2012. The objectives of the study are (i) to evaluate the resolution of the GPR technique in the field for detecting and locating anomalies caused by subsurface structures like cavities, fractures and faults, and (ii) to describe stratigraphic nomenclature of the subsurface rocks of the area. 2D interpre-tation of the obtained data and the geological information demonstrate a strong correlation between the GPR anomalies and the subsurface geology. Based upon the lateral and vertical velocity changes with depth, the thickness and orientation of the subsurface layers are outlined. Analysis of the exposed sec-tion shows good agreement between the estimated thicknesses of lithostratigraphic units and the quan-titative assessment of the radar waves velocity inferred from GPR data.

  13. Potential of Ground Penetrating Radar for the characterization of the shallow water table in the Mnasra region in Morocco

    Directory of Open Access Journals (Sweden)

    Imane SEBARI

    2016-03-01

    Full Text Available Morocco is a water-scarce country confronted with a severe dependence on rain-fed agriculture and dwindling groundwater reserves. Since 1995, new water regulation laws and management strategies have been promulgated providing a comprehensive framework for an integrated management. Moreover, water managers should have precise data on the current state of water tables depth in strategic aquifers. Unfortunately, the main source of these data are sporadic wells with no automated monitoring systems making the assessment of water table dynamics, costly, time consuming and out-phased with decision maker needs. In this respect, this paper focuses on the capability of Ground Penetrating Radar to determine the depth of shallow water table in Mnasra region, located in the Gharb region of Morocco as a pilot study to generalize its use in the future for groundwater dynamic monitoring purposes in Morocco. The experiment was undertaken using Mala 800 MHz shielded antennas and was able to probe the depth of the upper fresh water table at 3.75 m deep in the Mnasra aquifer in semi-arid conditions. Data collected by GPR can be used as substitute for well logs to enhance the monitoring of water tables in stressed areas during droughts and excessive recharges during rainy season.

  14. Deriving ice thickness, glacier volume and bedrock morphology of the Austre Lov\\'enbreen (Svalbard) using Ground-penetrating Radar

    CERN Document Server

    Saintenoy, Albane; Booth, Adam D; Tolle, F; Bernard, E; Laffly, Dominique; Marlin, C; Griselin, M

    2013-01-01

    The Austre Lov\\'enbreen is a 4.6 km2 glacier on the Archipelago of Svalbard (79 degrees N) that has been surveyed over the last 47 years in order of monitoring in particular the glacier evolution and associated hydrological phenomena in the context of nowadays global warming. A three-week field survey over April 2010 allowed for the acquisition of a dense mesh of Ground-penetrating Radar (GPR) data with an average of 14683 points per km2 (67542 points total) on the glacier surface. The profiles were acquired using a Mala equipment with 100 MHz antennas, towed slowly enough to record on average every 0.3 m, a trace long enough to sound down to 189 m of ice. One profile was repeated with 50 MHz antenna to improve electromagnetic wave propagation depth in scattering media observed in the cirques closest to the slopes. The GPR was coupled to a GPS system to position traces. Each profile has been manually edited using standard GPR data processing including migration, to pick the reflection arrival time from the ic...

  15. Evaluation and Improvement of Spectral Features for the Detection of Buried Explosive Hazards Using Forward-Looking Ground-Penetrating Radar

    Science.gov (United States)

    2012-07-01

    for the NIITEK ground penetrating radar using order weighted averaging operators for landmine detection”, Proc. SPIE 5415, 953-962 (2004). [9] Sun, Y...and Li, J., "Plastic landmine detection using time-frequency analysis for forward-looking ground - penetrating radar ”, Proc. SPIE 5089, 851-862...REPORT Evaluation and Improvement of Spectral Features for the Detection of Buried Explosive Hazards Using Forward-Looking Ground - Penetrating Radar 14

  16. Ground-penetrating radar investigation of St. Leonard's Crypt under the Wawel Cathedral (Cracow, Poland) - COST Action TU1208

    Science.gov (United States)

    Benedetto, Andrea; Pajewski, Lara; Dimitriadis, Klisthenis; Avlonitou, Pepi; Konstantakis, Yannis; Musiela, Małgorzata; Mitka, Bartosz; Lambot, Sébastien; Żakowska, Lidia

    2016-04-01

    historical interest. The TS presented an insight into the challenges, advantages and potential of GPR prospection in historical cities. Data examples from urban historical centres were presented and discussed. An introduction to electromagnetic modelling of GPR was provided. To widen the perspective, the school included an introduction to urban remote sensing, describing how high-resolution satellite imagery or alternative sources of image date can be exploited for urban feature extraction, to analyse population, energy use, and other aspects of the urban environment. In this work, data collected in St Leonard's Crypt will be presented for the first time. The activities focused on surveying the floor of the crypt, in order to obtain an image of the tomb of Bishop Maurus, verify whether further cavities were present and collect information about the subsurface of the crypt. GPR scans were taken on a 20 cm x 20 cm grid. Subsequently, an interesting area of smaller extent was chosen, where further data were collected on a 10 cm x 10 cm grid. We found out that the tomb of Bishop Maurus is shifted with respect to the inscription placed in the middle of the crypt and supposed to indicate its position. We could also detect the presence of another large cavity and estimate their size. All measurements were performed by using a CX-12 GPR pulsed system of MALA Geoscience. Acknowledgement The Authors are deeply grateful to the Parish of the Cathedral of St. Stanislaus BM and St. Wenceslas M, Cracow, Poland, for authorizing us to carry out the practical sessions of the Training School in St. Leonard's Crypt under the Wawel Cathedral. This was for all Trainers and Trainees a unique, touching and unforgettable experience. The Authors thank COST (www.cost.eu) for funding the Action TU1208 "Civil engineering applications of Ground Penetrating Radar" (www.GPRadar.eu) and for its constant support to the Action.

  17. Mobile acoustic system for the detection of surface-breaking cracks in pavement

    Science.gov (United States)

    Marzani, Alessandro; Rizzo, Piervincenzo; Lanza di Scalea, Francesco; Benzoni, Gianmario

    2004-07-01

    Monitoring the structural condition of road and airport pavement is an extremely critical task to ensure the safety and efficiency of teh transportation. The topic is relevant to both civil and military transportation infrastructure. The presence of damage in pavement, including surface cracking, depressions, swells, and wear, is inevitable due to the sever environmental and service loads that these structures must be subject to. Existing NDE techniques aimed at assessing the structural condition of pavement include Falling Weight Deflectometer, Ground Penetrating Radar, and acoustic methods based on surface waves. This paper presents improvements to the traditional surface-wave method for the detection of surface-breaking cracks in pavement. The advances include 1) the modeling of the problem as dipsersive waves propagating in a multilayer system, 2) the inclusion of post-processing algorithms based on the Wavelet Transform to improve the sensitivity and accuracy of the inspection, and 3) the use of non-contact, air-coupled acoustic detectors to enhance the mobility of the inspection unit. The crack detection procedure consists of first generating a dispersive wave with an impulse hammer, and then measuring the changes in velocity, amplitude and/or frequency content as the wave travels across the flaw with the aid of the Continuous Wavelet Transform. Multilayer wave propagation modeling provides a better understanding of the experimental results by predicting how the various frequencies interact with cracks of different depths. The results of field tests will be presented for both rigid (concrete-based) and flexible (bitumen-based) pavement with surface cracks.

  18. Using ground penetrating radar to assess the variability of snow water equivalent and melt in a mixed canopy forest, Northern Colorado

    Science.gov (United States)

    Webb, Ryan W.

    2017-09-01

    Snow is an important environmental variable in headwater systems that controls hydrological processes such as streamflow, groundwater recharge, and evapotranspiration. These processes will be affected by both the amount of snow available for melt and the rate at which it melts. Snow water equivalent (SWE) and snowmelt are known to vary within complex subalpine terrain due to terrain and canopy influences. This study assesses this variability during the melt season using ground penetrating radar to survey multiple plots in northwestern Colorado near a snow telemetry (SNOTEL) station. The plots include south aspect and flat aspect slopes with open, coniferous (subalpine fir, Abies lasiocarpa and engelman spruce, Picea engelmanii), and deciduous (aspen, populous tremuooides) canopy cover. Results show the high variability for both SWE and loss of SWE during spring snowmelt in 2014. The coefficient of variation for SWE tended to increase with time during snowmelt whereas loss of SWE remained similar. Correlation lengths for SWE were between two and five meters with melt having correlation lengths between two and four meters. The SNOTEL station regularly measured higher SWE values relative to the survey plots but was able to reasonably capture the overall mean loss of SWE during melt. Ground Penetrating Radar methods can improve future investigations with the advantage of non-destructive sampling and the ability to estimate depth, density, and SWE.

  19. Civil Engineering Applications of Ground Penetrating Radar Recent Advances @ the ELEDIA Research Center

    Science.gov (United States)

    Salucci, Marco; Tenuti, Lorenza; Nardin, Cristina; Oliveri, Giacomo; Viani, Federico; Rocca, Paolo; Massa, Andrea

    2014-05-01

    The application of non-destructive testing and evaluation (NDT/NDE) methodologies in civil engineering has raised a growing interest during the last years because of its potential impact in several different scenarios. As a consequence, Ground Penetrating Radar (GPR) technologies have been widely adopted as an instrument for the inspection of the structural stability of buildings and for the detection of cracks and voids. In this framework, the development and validation of GPR algorithms and methodologies represents one of the most active research areas within the ELEDIA Research Center of the University of Trento. More in detail, great efforts have been devoted towards the development of inversion techniques based on the integration of deterministic and stochastic search algorithms with multi-focusing strategies. These approaches proved to be effective in mitigating the effects of both nonlinearity and ill-posedness of microwave imaging problems, which represent the well-known issues arising in GPR inverse scattering formulations. More in detail, a regularized multi-resolution approach based on the Inexact Newton Method (INM) has been recently applied to subsurface prospecting, showing a remarkable advantage over a single-resolution implementation [1]. Moreover, the use of multi-frequency or frequency-hopping strategies to exploit the information coming from GPR data collected in time domain and transformed into its frequency components has been proposed as well. In this framework, the effectiveness of the multi-resolution multi-frequency techniques has been proven on synthetic data generated with numerical models such as GprMax [2]. The application of inversion algorithms based on Bayesian Compressive Sampling (BCS) [3][4] to GPR is currently under investigation, as well, in order to exploit their capability to provide satisfactory reconstructions in presence of single and multiple sparse scatterers [3][4]. Furthermore, multi-scaling approaches exploiting level

  20. Ground penetrating radar data analyzed in frequency and time domain for engineering issues

    Science.gov (United States)

    Capozzoli, Luigi; Giampaolo, Valeria; Votta, Mario; Rizzo, Enzo

    2014-05-01

    Non-destructive testing (NDT) allows to analyze reinforced concrete and masonry structures, in order to identify gaps, defects, delaminations, and fracture. In the field of engineering, non-invasive diagnostic is used to test the processes of construction and maintenance of buildings and artifacts of the individual components, to reduce analysis time and costs of intervention (Proto et al., 2010). Ground penetrating radar (GPR) allows to evaluate with a good effectiveness the state of conservation of engineering construction (Mellet 1995)). But there are some uncertainties in GPR data due to the complexity of artificial objects. In this work we try to evaluate the capability of GPR for the characterization of building structures in the laboratory and in-situ. In particular the focus of this research consists in integrate spectral analysis to time domain data to enhance information obtained in a classical GPR processing approach. For this reason we have applied spectral analysis to localize and characterize the presence of extraneous bodies located in a test site rebuilt in laboratory to simulate a part of a typical concrete road. The test site is a segment of a road superimposed on two different layers of sand and gravel of varying thickness inside which were introduced steel rebar, PVC and aluminium pipes. This structure has also been cracked in a predetermined area and hidden internal fractures were investigated. The GPR has allowed to characterize the panel in a non-invasive mode and radargrams were acquired using two-dimensional and three-dimensional models from data obtained with the use of 400, 900, 1500 and 2000 Mhz antennas. We have also studied with 2 GHz antenna a beam of 'to years precast bridge characterized by a high state of decay. The last case study consisted in the characterization of a radiant floor analyzed with an integrated use of GPR and infrared thermography. In the frequency domain analysis has been possible to determine variations in the

  1. Effect of elevated CO2 on coarse-root biomass in Florida scrub detected by ground-penetrating radar

    Science.gov (United States)

    Daniel B. Stover; Frank P. Day; John R Butnor; Bert G. Drake

    2007-01-01

    Growth and distribution of coarse roots in time and space represent a gap in our understanding of belowground ecology. Large roots may play a critical role in carbon sequestration belowground. Using ground-penetrating radar (GPR), we quantified coarseroot biomass from an open-top chamber experiment in a scrub-oak ecosystem at Kennedy Space Center, Florida, USA. GPR...

  2. The impact of light-colored pavements on active layer dynamics revealed by Ground-Penetrating Radar monitoring

    DEFF Research Database (Denmark)

    Jørgensen, Anders Stuhr; Ingeman-Nielsen, Thomas

    2008-01-01

    Ground-penetrating radar (GPR) has been used to study the variations in the depth of the frost table throughout a complete thaw-freeze season in Kangerlussuaq Airport, western Greenland. In autumn 2000, three test areas were painted white on the parking area of the airport in order to reduce...

  3. Ground penetrating radar for determining volumetric soil water content ; results of comparative measurements at two test sites

    NARCIS (Netherlands)

    Overmeeren, R.A. van; Sariowan, S.V.; Gehrels, J.C.

    1997-01-01

    Ground penetrating radar (GPR) can provide information on the soil water content of the unsaturated zone in sandy deposits via measurements from the surface, and so avoids drilling. Proof of this was found from measurements of radar wave velocities carried out ten times over 13 months at two test si

  4. A forward model for ground penetrating radar imaging of buried perfect electric conductors within the physical optics approximation

    DEFF Research Database (Denmark)

    Polat, Burak; Meincke, Peter

    2004-01-01

    A forward model for ground penetrating radar imaging of buried 3-D perfect electric conductors is addressed within the framework of diffraction tomography. The similarity of the present forward model derived within the physical optics approximation with that derived within the first Born...

  5. Detectability of underground electrical cables junction with a ground penetrating radar: electromagnetic simulation and experimental measurements

    Science.gov (United States)

    Liu, Xiang; serhir, mohammed; kameni, abelin; lambert, marc; pichon, lionel

    2016-04-01

    For a company like Electricity De France (EDF), being able to detect accurately using non-destructive methods the position of the buried junction between two underground cables is a crucial issue. The junction is the linking part where most maintenance operations are carried out. The challenge of this work is to conduct a feasibility study to confirm or deny the relevance of Ground Penetrating Radar (GPR) to detect these buried junctions in their actual environment against clutter. Indeed, the cables are buried in inhomogeneous medium at around 80cm deep. To do this, the study is conducted in a numerical environment. We use the 3D simulation software CST MWS to model a GPR scenario. In this simulation, we place the already optimized bowtie antennas operating in the frequency band [0.5 GHz - 3 GHz] in front of wet soil (dispersive) and dry soil where the underground cable is placed at 80cm deep. We collect the amplitude and phase of the reflected waves in order to detect the contrast provoked by the geometric dimensions variation of the cable [1] (diameter of the cable is 48mm and the diameter of the junction 74mm). The use of an ultra-wideband antenna is necessary to reconcile resolution and penetration of electromagnetic waves in the medium to be characterized. We focus on the performance of the GPR method according to the characteristics of the surrounding medium in which the electric cables are buried, the polarization of the Tx and Rx antennas. The experimental measurement collected in the EDF site will be presented. The measured data are processed using the clutter reduction method based on digital filtering [2]. We aim at showing that using the developed bowtie antennas that the GPR technique is well adapted for the cable junction localization even in cluttered environment. References [1] D. J. Daniels, "Surface-Penetrating Radar", London, IEE 1996. [2] Potin, D.; Duflos, E.; Vanheeghe, P., "Landmines Ground-Penetrating Radar Signal Enhancement by Digital

  6. On Recovering Missing Ground Penetrating Radar Traces by Statistical Interpolation Methods

    Directory of Open Access Journals (Sweden)

    Gonzalo Safont

    2014-08-01

    Full Text Available Missing traces in ground penetrating radar (GPR B-scans (radargrams may appear because of limited scanning resolution, failures during the acquisition process or the lack of accessibility to some areas under test. Four statistical interpolation methods for recovering these missing traces are compared in this paper: Kriging, Wiener structures, Splines and the expectation assuming an independent component analyzers mixture model (E-ICAMM. Kriging is an adaptation to the spatial context of the linear least mean squared error estimator. Wiener structures improve the linear estimator by including a nonlinear scalar function. Splines are a commonly used method to interpolate GPR traces. This consists of piecewise-defined polynomial curves that are smooth at the connections (or knots between pieces. E-ICAMM is a new method proposed in this paper. E-ICAMM consists of computing the optimum nonlinear estimator (the conditional mean assuming a non-Gaussian mixture model for the joint probability density in the observation space. The proposed methods were tested on a set of simulated data and a set of real data, and four performance indicators were computed. Real data were obtained by GPR inspection of two replicas of historical walls. Results show the superiority of E-ICAMM in comparison with the other three methods in the application of reconstructing incomplete B-scans.

  7. Urban archaeological investigations using surface 3D Ground Penetrating Radar and Electrical Resistivity Tomography methods

    Science.gov (United States)

    Papadopoulos, Nikos; Sarris, Apostolos; Yi, Myeong-Jong; Kim, Jung-Ho

    2009-02-01

    Ongoing and extensive urbanisation, which is frequently accompanied with careless construction works, may threaten important archaeological structures that are still buried in the urban areas. Ground Penetrating Radar (GPR) and Electrical Resistivity Tomography (ERT) methods are most promising alternatives for resolving buried archaeological structures in urban territories. In this work, three case studies are presented, each of which involves an integrated geophysical survey employing the surface three-dimensional (3D) ERT and GPR techniques, in order to archaeologically characterise the investigated areas. The test field sites are located at the historical centres of two of the most populated cities of the island of Crete, in Greece. The ERT and GPR data were collected along a dense network of parallel profiles. The subsurface resistivity structure was reconstructed by processing the apparent resistivity data with a 3D inversion algorithm. The GPR sections were processed with a systematic way, applying specific filters to the data in order to enhance their information content. Finally, horizontal depth slices representing the 3D variation of the physical properties were created. The GPR and ERT images significantly contributed in reconstructing the complex subsurface properties in these urban areas. Strong GPR reflections and high-resistivity anomalies were correlated with possible archaeological structures. Subsequent excavations in specific places at both sites verified the geophysical results. The specific case studies demonstrated the applicability of ERT and GPR techniques during the design and construction stages of urban infrastructure works, indicating areas of archaeological significance and guiding archaeological excavations before construction work.

  8. Multiple instance learning framework for landmine detection using ground-penetrating radar

    Science.gov (United States)

    Manandhar, A.; Morton, K. D.; Collins, L. M.; Torrione, P. A.

    2011-06-01

    Ground Penetrating Radar (GPR) data provides a powerful technique to identify subsurface buried threats. Although GPR data contains a three-dimensional representation of the subsurface, object truth (i.e. labels and positions of true threat objects in training lanes) is often provided in only two dimensions (GPS coordinates along the earth's surface). To mitigate uncertainty in an object's location in depth, many successful feature extraction/ object recognition techniques in GPR extract feature vectors from several depth regions, and attempt to combine information across these feature vectors to make final decisions. However, many machine learning techniques are not well suited for learning under these conditions. Multiple Instance Learning (MIL) is a type of supervised learning method in which labels are available for sets of samples, but not for individual samples. The goal of learning in MIL is to classify new sets of samples as they become available. This set-based framework is useful in processing GPR responses since features are often extracted independently from multiple un-labeled depth bins, and thus a set of features is produced at each potential threat location. In this work, a comparison of several previous approaches to MlL applied to landmine detection in GPR data is presented. One recent algorithm, the p-Posterior Mixture Model approach (pPMM) is given special attention, and several slight modifications to the pPMM approach are presented and compared.

  9. Context-dependent fusion for landmine detection with ground-penetrating radar

    Science.gov (United States)

    Frigui, Hichem; Zhang, Lijun; Gader, Paul; Ho, Dominic

    2007-04-01

    We present a novel method for fusing the results of multiple landmine detection algorithms that use different types of features and different classification methods. The proposed fusion method, called Context-Dependent Fusion (CDF) is motivated by the fact that the relative performance of different detectors can vary significantly depending on the mine type, geographical site, soil and weather conditions, and burial depth. The training part of CDF has two components: context extraction and algorithm fusion. In context extraction, the features used by the different algorithms are combined and used to partition the feature space into groups of similar signatures, or contexts. The algorithm fusion component assigns an aggregation weight to each detector in each context based on its relative performance within the context. Results on large and diverse Ground Penetrating Radar data collections show that the proposed method can identify meaningful and coherent clusters and that different expert algorithms can be identified for the different contexts. Our initial experiments have also indicated that the context-dependent fusion outperforms all individual detectors.

  10. Physics-based features for identifying contextual factors affecting landmine detection with ground-penetrating radar

    Science.gov (United States)

    Ratto, Christopher R.; Morton, Kenneth D., Jr.; Collins, Leslie M.; Torrione, Peter A.

    2011-06-01

    It has been established throughout the ground-penetrating radar (GPR) literature that environmental factors can severely impact the performance of GPR sensors in landmine detection applications. Over the years, electromagnetic inversion techniques have been proposed for determining these factors with the goal of mitigating performance losses. However, these techniques are often computationally expensive and require models and responses from canonical targets, and therefore may not be appropriate for real-time route-clearance applications. An alternative technique for mitigating performance changes due to environmental factors is context-dependent classification, in which decision rules are adjusted based on contextual shifts identified from the GPR data. However, analysis of the performance of context-dependent learning has been limited to qualitative comparisons of contextually-similar GPR signatures and quantitative improvement to the ROC curve, while the actual information extracted regarding soils has not been investigated thoroughly. In this work, physics-based features of GPR data used in previous context-dependent approaches were extracted from simulated GPR data generated through Finite-Difference Time-Domain (FDTD) modeling. Statistical techniques where then used to predict several potential contextual factors, including soil dielectric constant, surface roughness, amount of subsurface clutter, and the existence of subsurface layering, based on the features. Results suggest that physics-based features of the GPR background may contain informatin regarding physical properties of the environment, and contextdependent classification based on these features can exploit information regarding these potentially-important environmental factors.

  11. Image segmentation techniques for improved processing of landmine responses in ground-penetrating radar data

    Science.gov (United States)

    Torrione, Peter A.; Collins, Leslie

    2007-04-01

    As ground penetrating radar sensor phenomenology improves, more advanced statistical processing approaches become applicable to the problem of landmine detection in GPR data. Most previous studies on landmine detection in GPR data have focused on the application of statistics and physics based prescreening algorithms, new feature extraction approaches, and improved feature classification techniques. In the typical framework, prescreening algorithms provide spatial location information of anomalous responses in down-track / cross-track coordinates, and feature extraction algorithms are then tasked with generating low-dimensional information-bearing feature sets from these spatial locations. However in time-domain GPR, a significant portion of the data collected at prescreener flagged locations may be unrelated to the true anomaly responses - e.g. ground bounce response, responses either temporally "before" or "after" the anomalous response, etc. The ability to segment the information-bearing region of the GPR image from the background of the image may thus provide improved performance for feature-based processing of anomaly responses. In this work we will explore the application of Markov random fields (MRFs) to the problem of anomaly/background segmentation in GPR data. Preliminary results suggest the potential for improved feature extraction and overall performance gains via application of image segmentation approaches prior to feature extraction.

  12. Real-time Gaussian Markov random-field-based ground tracking for ground penetrating radar data

    Science.gov (United States)

    Bradbury, Kyle; Torrione, Peter A.; Collins, Leslie

    2009-05-01

    Current ground penetrating radar algorithms for landmine detection require accurate estimates of the location of the air/ground interface to maintain high levels of performance. However, the presence of surface clutter, natural soil roughness, and antenna motion lead to uncertainty in these estimates. Previous work on improving estimates of the location of the air/ground interface have focused on one-dimensional filtering techniques to localize the air/ground interface. In this work, we propose an algorithm for interface localization using a 2- D Gaussian Markov random field (GMRF). The GMRF provides a statistical model of the surface structure, which enables the application of statistical optimization techniques. In this work, the ground location is inferred using iterated conditional modes (ICM) optimization which maximizes the conditional pseudo-likelihood of the GMRF at a point, conditioned on its neighbors. To illustrate the efficacy of the proposed interface localization approach, pre-screener performance with and without the proposed ground localization algorithm is compared. We show that accurate localization of the air/ground interface provides the potential for future performance improvements.

  13. Landmine detection with ground penetrating radar using discrete hidden Markov models with symbol dependent features

    Science.gov (United States)

    Frigui, Hichem; Missaoui, Oualid; Gader, Paul

    2008-04-01

    In this paper, we propose an efficient Discrete Hidden Markov Models (DHMM) for landmine detection that rely on training data to learn the relevant features that characterize different signatures (mines and non-mines), and can adapt to different environments and different radar characteristics. Our work is motivated by the fact that mines and clutter objects have different characteristics depending on the mine type, soil and weather conditions, and burial depth. Thus, ideally different sets of specialized features may be needed to achieve high detection and low false alarm rates. The proposed approach includes three main components: feature extraction, clustering, and DHMM. First, since we do not assume that the relevant features for the different signatures are known a priori, we proceed by extracting several sets of features for each signature. Then, we apply a clustering and feature discrimination algorithm to the training data to quantize it into a set of symbols and learn feature relevance weights for each symbol. These symbols and their weights are then used in a DHMM framework to learn the parameters of the mine and the background models. Preliminary results on large and diverse ground penetrating radar data show that the proposed method outperforms the basic DHMM where all the features are treated equally important.

  14. gprMax: Open source software to simulate electromagnetic wave propagation for Ground Penetrating Radar

    Science.gov (United States)

    Warren, Craig; Giannopoulos, Antonios; Giannakis, Iraklis

    2016-12-01

    gprMax is open source software that simulates electromagnetic wave propagation, using the Finite-Difference Time-Domain (FDTD) method, for the numerical modelling of Ground Penetrating Radar (GPR). gprMax was originally developed in 1996 when numerical modelling using the FDTD method and, in general, the numerical modelling of GPR were in their infancy. Current computing resources offer the opportunity to build detailed and complex FDTD models of GPR to an extent that was not previously possible. To enable these types of simulations to be more easily realised, and also to facilitate the addition of more advanced features, gprMax has been redeveloped and significantly modernised. The original C-based code has been completely rewritten using a combination of Python and Cython programming languages. Standard and robust file formats have been chosen for geometry and field output files. New advanced modelling features have been added including: an unsplit implementation of higher order Perfectly Matched Layers (PMLs) using a recursive integration approach; diagonally anisotropic materials; dispersive media using multi-pole Debye, Drude or Lorenz expressions; soil modelling using a semi-empirical formulation for dielectric properties and fractals for geometric characteristics; rough surface generation; and the ability to embed complex transducers and targets.

  15. Electromagnetic Simulations of Ground-Penetrating Radar Propagation near Lunar Pits and Lava Tubes

    Science.gov (United States)

    Zimmerman, M. I.; Carter, L. M.; Farrell, W. M.; Bleacher, J. E.; Petro, N. E.

    2013-01-01

    Placing an Orion capsule at the Earth-Moon L2 point (EML2) would potentially enable telerobotic operation of a rover on the lunar surface. The Human Exploration Virtual Institute (HEVI) is proposing that rover operations be carried out near one of the recently discovered lunar pits, which may provide radiation shielding for long duration human stays as well as a cross-disciplinary, science-rich target for nearer-term telerobotic exploration. Ground penetrating radar (GPR) instrumentation included onboard a rover has the potential to reveal many details of underground geologic structures near a pit, as well as characteristics of the pit itself. In the present work we employ the full-wave electromagnetic code MEEP to simulate such GPR reflections from a lunar pit and other subsurface features including lava tubes. These simulations will feed forward to mission concepts requiring knowledge of where to hide from harmful radiation and other environmental hazards such as plama charging and extreme diurnal temperatures.

  16. Ground-penetrating radar reveals ice thickness and undisturbed englacial layers at Kilimanjaro's Northern Ice Field

    Science.gov (United States)

    Bohleber, Pascal; Sold, Leo; Hardy, Douglas R.; Schwikowski, Margit; Klenk, Patrick; Fischer, Andrea; Sirguey, Pascal; Cullen, Nicolas J.; Potocki, Mariusz; Hoffmann, Helene; Mayewski, Paul

    2017-02-01

    Although its Holocene glacier history is still subject to debate, the ongoing iconic decline of Kilimanjaro's largest remaining ice body, the Northern Ice Field (NIF), has been documented extensively based on surface and photogrammetric measurements. The study presented here adds, for the first time, ground-penetrating radar (GPR) data at centre frequencies of 100 and 200 MHz to investigate bed topography, ice thickness and internal stratigraphy at NIF. The direct comparison of the GPR signal to the visible glacier stratigraphy at NIF's vertical walls is used to validate ice thickness and reveals that the major internal reflections seen by GPR can be associated with dust layers. Internal reflections can be traced consistently within our 200 MHz profiles, indicating an uninterrupted, spatially coherent internal layering within NIF's central flat area. We show that, at least for the upper 30 m, it is possible to follow isochrone layers between two former NIF ice core drilling sites and a sampling site on NIF's vertical wall. As a result, these isochrone layers provide constraints for future attempts at linking age-depth information obtained from multiple locations at NIF. The GPR profiles reveal an ice thickness ranging between (6.1 ± 0.5) and (53.5 ± 1.0) m. Combining these data with a very high resolution digital elevation model we spatially extrapolate ice thickness and give an estimate of the total ice volume remaining at NIF's southern portion as (12.0 ± 0.3) × 106 m3.

  17. Curvelet filter based prescreener for explosive hazard detection in hand-held ground penetrating radar

    Science.gov (United States)

    White, Julie L.; Anderson, Derek T.; Ball, John E.; Parker, Brian

    2016-05-01

    Explosive hazards, above and below ground, are a serious threat to civilians and soldiers. In an attempt to mitigate these threats, different forms of explosive hazard detection (EHD) exist; e.g., multi-sensor hand-held platforms, downward looking and forward looking vehicle mounted platforms, etc. Robust detection of these threats resides in the processing and fusion of different data from multiple sensing modalities, e.g., radar, infrared, electromagnetic induction (EMI), etc. Herein, we focus on a new energy-based prescreener in hand-held ground penetrating radar (GPR). First, we Curvelet filter B-scan signal data using either Reverse-Reconstruction followed by Enhancement (RRE) or selectivity with respect to wedge information in the Curvelet transform. Next, we aggregate the result of a bank of matched filters and run a size contrast filter with Bhattacharyya distance. Alarms are then combined using weighted mean shift clustering. Results are demonstrated in the context of receiver operating characteristics (ROC) curve performance on data from a U. S. Army test site that contains multiple target and clutter types, burial depths and times of the day.

  18. An Iterative Approach to Ground Penetrating Radar at the Maya Site of Pacbitun, Belize

    Directory of Open Access Journals (Sweden)

    Sheldon Skaggs

    2016-09-01

    Full Text Available Ground penetrating radar (GPR surveys provide distinct advantages for archaeological prospection in ancient, complex, urban Maya sites, particularly where dense foliage or modern debris may preclude other remote sensing or geophysical techniques. Unidirectional GPR surveys using a 500 MHz shielded antenna were performed at the Middle Preclassic Maya site of Pacbitun, Belize. The survey in 2012 identified numerous linear and circular anomalies between 1 m and 2 m deep. Based on these anomalies, one 1 m × 4 m unit and three smaller units were excavated in 2013. These test units revealed a curved plaster surface not previously found at Pacbitun. Post-excavation, GPR data were reprocessed to best match the true nature of excavated features. Additional GPR surveys oriented perpendicular to the original survey confirmed previously detected anomalies and identified new anomalies. The excavations provided information on the sediment layers in the survey area, which allowed better identification of weak radar reflections of the surfaces of a burnt, Middle Preclassic temple in the northern end of the survey area. Additional excavations of the area in 2014 and 2015 revealed it to be a large square structure, which was named El Quemado.

  19. An Experimental and Numerical Study on Embedded Rebar Diameter in Concrete Using Ground Penetrating Radar

    Directory of Open Access Journals (Sweden)

    Md Istiaque Hasan

    2016-01-01

    Full Text Available High frequency ground penetrating radar (GPR has been widely used to detect and locate rebars in concrete. In this paper, a method of estimating the diameter of steel rebars in concrete with GPR is investigated. The relationship between the maximum normalized positive GPR amplitude from embedded rebars and the rebar diameter was established. Concrete samples with rebars of different diameters were cast and the maximum normalized amplitudes were recorded using a 2.6 GHz GPR antenna. Numerical models using GPRMAX software were developed and verified with the experimental data. The numerical models were then used to investigate the effect of dielectric constant of concrete and concrete cover on the maximum normalized amplitude. The results showed that there is an approximate linear relationship between the rebar diameter and the maximum GPR normalized amplitude. The developed models can be conveniently used to estimate the embedded rebar diameters in existing concrete with GPR scanning; if the concrete is homogeneous, the cover depth is known and the concrete dielectric constant is also known. The models will be highly beneficial in forensic investigations of existing concrete structures with unknown rebar sizes and locations.

  20. Detection of shallow buried objects using an autoregressive model on the ground penetrating radar signal

    Science.gov (United States)

    Nabelek, Daniel P.; Ho, K. C.

    2013-06-01

    The detection of shallow buried low-metal content objects using ground penetrating radar (GPR) is a challenging task. This is because these targets are right underneath the ground and the ground bounce reflection interferes with their detections. They do not create distinctive hyperbolic signatures as required by most existing GPR detection algorithms due to their special geometric shapes and low metal content. This paper proposes the use of the Autoregressive (AR) modeling method for the detection of these targets. We fit an A-scan of the GPR data to an AR model. It is found that the fitting error will be small when such a target is present and large when it is absent. The ratio of the energy in an Ascan before and after AR model fitting is used as the confidence value for detection. We also apply AR model fitting over scans and utilize the fitting residual energies over several scans to form a feature vector for improving the detections. Using the data collected from a government test site, the proposed method can improve the detection of this kind of targets by 30% compared to the pre-screener, at a false alarm rate of 0.002/m2.

  1. A Review on Migration Methods in B-Scan Ground Penetrating Radar Imaging

    Directory of Open Access Journals (Sweden)

    Caner Özdemir

    2014-01-01

    Full Text Available Even though ground penetrating radar has been well studied and applied by many researchers for the last couple of decades, the focusing problem in the measured GPR images is still a challenging task. Although there are many methods offered by different scientists, there is not any complete migration/focusing method that works perfectly for all scenarios. This paper reviews the popular migration methods of the B-scan GPR imaging that have been widely accepted and applied by various researchers. The brief formulation and the algorithm steps for the hyperbolic summation, the Kirchhoff migration, the back-projection focusing, the phase-shift migration, and the ω-k migration are presented. The main aim of the paper is to evaluate and compare the migration algorithms over different focusing methods such that the reader can decide which algorithm to use for a particular application of GPR. Both the simulated and the measured examples that are used for the performance comparison of the presented algorithms are provided. Other emerging migration methods are also pointed out.

  2. Multiple kernel learning for explosive hazard detection in forward-looking ground-penetrating radar

    Science.gov (United States)

    Havens, Timothy C.; Stone, Kevin; Anderson, Derek T.; Keller, James M.; Ho, K. C.; Ton, Tuan T.; Wong, David C.; Soumekh, Mehrdad

    2012-06-01

    This paper proposes an effective anomaly detection algorithm for forward-looking ground-penetrating radar (FLGPR). The challenges in detecting explosive hazards with FLGPR are that there are multiple types of targets buried at different depths in a highly-cluttered environment. A wide array of target and clutter signatures exist, which makes classifier design difficult. Recent work in this application has focused on fusing the classifier results from multiple frequency subband images. Each sub-band classifier is trained on suites of image features, such as histogram of oriented gradients (HOG) and local binary patterns (LBP). This prior work fused the sub-band classifiers by, first, choosing the top-ranked feature at each frequency sub-band in the training data and then accumulating the sub-band results in a confidence map. We extend this idea by employing multiple kernel learning (MKL) for feature-level fusion. MKL fuses multiple sources of information and/or kernels by learning the weights of a convex combination of kernel matrices. With this method, we are able to utilize an entire suite of features for anomaly detection, not just the top-ranked feature. Using FLGPR data collected at a US Army test site, we show that classifiers trained using MKL show better explosive hazard detection capabilities than single-kernel methods.

  3. An element-free Galerkin method for ground penetrating radar numerical simulation

    Institute of Scientific and Technical Information of China (English)

    冯德山; 郭荣文; 王洪华

    2015-01-01

    An element-free Galerkin method (EFGM) is used to solve the two-dimensional (2D) ground penetrating radar (GPR) modelling problems, due to its simple pre-processing, the absence of elements and high accuracy. Different from element-based numerical methods, this approach makes nodes free from the elemental restraint and avoids the explicit mesh discretization. First, we derived the boundary value problem for the 2D GPR simulation problems. Second, a penalty function approach and a boundary condition truncated method were used to enforce the essential and the absorbing boundary conditions, respectively. A three-layered GPR model was used to verify our element-free approach. The numerical solutions show that our solutions have an excellent agreement with solutions of a finite element method (FEM). Then, we used the EFGM to simulate one more complex model to show its capability and limitations. Simulation results show that one obvious advantage of EFGM is the absence of element mesh, which makes the method very flexible. Due to the use of MLS fitting, a key feature of EFM, is that both the dependent variable and its gradient are continuous and have high precision.

  4. Apparent apertures from ground penetrating radar data and their relation to heterogeneous aperture fields

    Science.gov (United States)

    Shakas, A.; Linde, N.

    2017-06-01

    Considering fractures with heterogeneous aperture distributions, we explore the reliability of constant-aperture estimates derived from ground penetrating radar (GPR) reflection data. We generate geostatistical fracture aperture realizations that are characterized by the same mean-aperture and variance, but different Hurst exponents and cut-off lengths. For each of the 16 classes of heterogeneity considered, we generate 1000 fracture realizations from which we compute GPR reflection data using our recent effective-dipole forward model. We then use each (noise-contaminated) data set individually to invert for a single 'apparent' aperture, that is, we assume that the fracture aperture is homogeneous. We find that the inferred 'apparent' apertures are only reliable when fracture heterogeneity is non-fractal (the Hurst exponent is close to 1) and the scale of the dominant aperture heterogeneities is larger than the first Fresnel zone. These results are a direct consequence of the nonlinear character of the thin-bed reflection coefficients. As fracture heterogeneity is ubiquitous and often fractal, our results suggest that robust field-based inference of fracture aperture can only be achieved by accounting for the nonlinear response of fracture heterogeneity on GPR data.

  5. Recursive impedance inversion of ground-penetrating radar data in stochastic media

    Science.gov (United States)

    Zeng, Zhao-Fa; Chen, Xiong; Li, Jing; Chen, Ling-Na; Lu, Qi; Liu, Feng-Shan

    2015-12-01

    The travel time and amplitude of ground-penetrating radar (GPR) waves are closely related to medium parameters such as water content, porosity, and dielectric permittivity. However, conventional estimation methods, which are mostly based on wave velocity, are not suitable for real complex media because of limited resolution. Impedance inversion uses the reflection coefficient of radar waves to directly calculate GPR impedance and other parameters of subsurface media. We construct a 3D multiscale stochastic medium model and use the mixed Gaussian and exponential autocorrelation function to describe the distribution of parameters in real subsurface media. We introduce an elliptical Gaussian function to describe local random anomalies. The tapering function is also introduced to reduce calculation errors caused by the numerical simulation of discrete grids. We derive the impedance inversion workflow and test the calculation precision in complex media. Finally, we use impedance inversion to process GPR field data in a polluted site in Mongolia. The inversion results were constrained using borehole data and validated by resistivity data.

  6. Improving Indonesian peatland C stock estimates using ground penetrating radar (GPR) and electrical resistivity imaging (ERI)

    Science.gov (United States)

    Terry, N.; Comas, X.; Slater, L. D.; Warren, M.; Kolka, R. K.; Kristijono, A.; Sudiana, N.; Nurjaman, D.; Darusman, T.

    2014-12-01

    Tropical peatlands sequester an estimated 15% of the carbon pool from peatlands worldwide. Indonesian peatlands account for approximately 65% of all tropical peat, and are believed to be the largest global source of carbon dioxide emissions to the atmosphere from degrading peat. However, there is great uncertainty in these estimates due to insufficient data regarding the thickness of organic peat soils and their carbon content. Meanwhile, Indonesian peatlands are threatened by heightening pressure to drain and develop. Indirect geophysical methods have garnered interest for their potential to non-invasively estimate peat depth and gas content in boreal peatlands. Drawing from these techniques, we employed ground penetrating radar (GPR) and electrical resistivity imaging (ERI) in tandem with direct methods (core sampling) to evaluate the potential of these methods for tropical peatland mapping at 2 distinct study sites on West Kalimantan (Indonesia). We find that: [1] West Kalimantan peatland thicknesses estimated from GPR and ERI in intermediate/shallow peat can vary substantially over short distances (for example, > 2% over less than 0.02° surface topography gradient), [2] despite having less vertical resolution, ERI is able to better resolve peatland thickness in deep peat, and [3] GPR provides useful data regarding peat matrix attributes (such as the presence of wood layers). These results indicate GPR and ERI could help reduce uncertainty in carbon stocks and aid in responsible land management decisions in Indonesia.

  7. Exploring Soil Layers and Water Tables with Ground-Penetrating Radar

    Institute of Scientific and Technical Information of China (English)

    K. ROTH; U. WOLLSCHLAGER; CHENG Zhu-Hua; ZHANG Jia-Bao

    2004-01-01

    Ground-penetrating radar (GPR) has been used predominantly for environments with low electrical conductivity like freshwater aquifers, glaciers, or dry sandy soils. The objective of the present study was to explore its application for mapping in subsurface agricultural soils to a depth of several meters. For a loamy sand and a clayey site on the North China Plain, clay inclusions in the sand were detected; the thickness, inclination, and continuity of the confining clay and silt layers was assessed; and a local water table was mapped. Direct sampling (soil coring and profiling) in the top meter and independent measurement of the water table were utilized to confirm the findings. Also, effective estimates of the dielectric number for the site with the dielectric number of moist clayey soils depending strongly on frequency were obtained. Thus, important properties of soils, like the arrangement and type of layers and in particular their continuity and inclination, could be explored with moderate efforts for rather large areas to help find optimal locations for the time-consuming and expensive measurements which would be necessary to detail a model of the subsurface.

  8. Fault Detection Using Polarimetric Single-Input-Multi-Output Ground Penetrating Radar Technique in Mason, Texas

    Science.gov (United States)

    Amara, A.; Everett, M. E.

    2014-12-01

    At the Mason Mountain Wildlife Management Area (MMWMA) near Mason, Texas, we conducted a 2D ground penetrating radar (GPR) survey using single-input-multi-output (SIMO) acquisition technique to image a Pennsylvanian high-angle normal fault. At the MMWMA, the surface geology is mapped extensively but the subsurface remains largely unknown. The main objective of our study is to develop a detailed subsurface structural image of the fault and evaluate existing hypotheses on fault development. Also, to develop and apply a new methodology based on Polarimetric SIMO acquisition geometry. This new methodology allows the subsurface structures to be viewed simultaneously from different angles and can help reduce noise caused by the heterogeneities that affect the electromagnetic waves. We used a pulseEKKO pro 200 GPR with 200 MHz antennae to acquire 8 north-south lines across the fault. Each line is 30 meters long with the transmitter starting on the Town Mountain Granite, footwall, with the receiver stepping 40 cm until the end of the line crossing the fault on to the Hickory Sandstone, hanging wall. Each pass consisted of a stationary transmitter antenna and the moving receiver antenna. The data were initially processed with standard steps including low-cut dewow filter, background subtraction filter and gain control. Advanced processing techniques include migration, phased array processing, velocity analysis, and normal moveout. We will compare the GPR results with existing geophysical datasets at the same site, including electromagnetic (EM), seismic, and seismoelectric.

  9. Frozen: The Potential and Pitfalls of Ground-Penetrating Radar for Archaeology in the Alaskan Arctic

    Directory of Open Access Journals (Sweden)

    Thomas M. Urban

    2016-12-01

    Full Text Available Ground-penetrating radar (GPR offers many advantages for assessing archaeological potential in frozen and partially frozen contexts in high latitude and alpine regions. These settings pose several challenges for GPR, including extreme velocity changes at the interface of frozen and active layers, cryogenic patterns resulting in anomalies that can easily be mistaken for cultural features, and the difficulty in accessing sites and deploying equipment in remote settings. In this study we discuss some of these challenges while highlighting the potential for this method by describing recent successful investigations with GPR in the region. We draw on cases from Bering Land Bridge National Preserve, Cape Krusenstern National Monument, Kobuk Valley National Park, and Gates of the Arctic National Park and Preserve. The sites required small aircraft accessibility with light equipment loads and minimal personnel. The substrates we investigate include coastal saturated active layer over permafrost, interior well-drained active layer over permafrost, a frozen thermo-karst lake, and an alpine ice patch. These examples demonstrate that GPR is effective at mapping semi-subterranean house remains in several contexts, including houses with no surface manifestation. GPR is also shown to be effective at mapping anomalies from the skeletal remains of a late Pleistocene mammoth frozen in ice. The potential for using GPR in ice and snow patch archaeology, an area of increasing interest with global environmental change exposing new material each year, is also demonstrated.

  10. Application of ground-penetrating radar technique to evaluate the waterfront location in hardened concrete

    Science.gov (United States)

    Rodríguez-Abad, Isabel; Klysz, Gilles; Martínez-Sala, Rosa; Balayssac, Jean Paul; Mené-Aparicio, Jesús

    2016-12-01

    The long-term performance of concrete structures is directly tied to two factors: concrete durability and strength. When assessing the durability of concrete structures, the study of the water penetration is paramount, because almost all reactions like corrosion, alkali-silica, sulfate, etc., which produce their deterioration, require the presence of water. Ground-penetrating radar (GPR) has shown to be very sensitive to water variations. On this basis, the objective of this experimental study is, firstly, to analyze the correlation between the water penetration depth in concrete samples and the GPR wave parameters. To do this, the samples were immersed into water for different time intervals and the wave parameters were obtained from signals registered when the antenna was placed on the immersed surface of the samples. Secondly, a procedure has been developed to be able to determine, from those signals, the reliability in the detection and location of waterfront depths. The results have revealed that GPR may have an enormous potential in this field, because excellent agreements were found between the correlated variables. In addition, when comparing the waterfront depths calculated from GPR measurements and those visually registered after breaking the samples, we observed that they totally agreed when the waterfront was more than 4 cm depth.

  11. Circular polarized stepped frequency ground-penetrating radar for humanitarian demining

    Science.gov (United States)

    Thaysen, Jesper; Jakobsen, Kaj B.; Appel-Hansen, Joergen

    2001-10-01

    A cavity backed coplanar waveguide to coplanar strip - fed logarithmic uniplanar spiral antenna, which covers a 9 to 1 band-width with a return loss better than 10 dB from 0.4 to 3.8 GHz is presented. A wideband balun, with an insertion loss of less than 3 dB in the frequency band of operation, was developed for the balanced antenna feed. To aid the balun and antenna design, a method of moment computer program, was used to predict the performance of the spiral antenna. Measurements in an anechoic are made in order to verify the simulated far-field radiation pattern, the simulated polarisation, and the simulated input impedance. Additional advantage of the fabricated antenna is the low cost FR-4 substrate used for the antenna combined with the advantages of the uniplanar circuit, makes this configuration suitable as a low-cost wideband antenna. The constructed uniplanar spiral antenna is very well suited to be used in a stepped frequency ground penetrating radar for humanitarian demining due to the very wide bandwidth, relative small size. Successful detection of a small 5.4 cm non-metallic AP-mines in a pseudo minefield are presented.

  12. Disturbances in the soil: finding buried bodies and other evidence using ground penetrating radar.

    Science.gov (United States)

    Miller, P S

    1996-07-01

    Ground penetrating radar (GPR) is an efficient and effective means to search for buried evidence, whether it be a clandestine grave, formal burial, or certain missing articles from a crime scene. The procedures for GPR used by the U.S. Army Central Identification Laboratory, Hawaii (CILHI), are the result of several years of experimentation on a variety of ground surfaces in Hawaii, Southeast Asia and the mainland U.S. This remote sensing method does not usually provide direct information that there is a body or other specific object beneath the ground. Most of the time the GPR has been used to determine where a target object is not located. The key feature of GPR is that it can detect recent changes in shallow soil conditions caused by the disturbance of soil and the intrusion of different material. Using the methods described here, the investigator should be able to determine the precise metric grid coordinates for a subsurface disturbance, as well as the approximate size, the general shape, and the depth of the buried material. Success will vary with soil conditions. The conditions suitable or not practical for using GPR are summarized. This remote sensing technology can have wider use in crime scene investigations due to the recent introduction of more user-friendly software and more portable hardware.

  13. Possibilities of ground penetrating radar usage within acceptance tests of rigid pavements

    Science.gov (United States)

    Stryk, Josef; Matula, Radek; Pospisil, Karel

    2013-10-01

    Within the road pavement acceptance tests, destructive as well as non-destructive tests of individual road layers are performed to verify the standard requirements. The article describes a method for providing quick, effective and sufficiently accurate measurements of both dowel and tie bar positions in concrete pavements, using a two-channel ground penetrating radar (GPR). Measurements were carried out in laboratory and in-situ conditions. A special hand cart for field measurements, set for the testing requirements, was designed. It was verified that following the correct measuring and assessment method, it is possible to reach accuracy of determining the in-built rebar up to 1 cm in vertical direction and up to 1.5 cm per 11.5 m of measured length in horizontal direction. In the in-situ tests, GPR identification of possible anomalies due to the phase of concrete pavement laying was presented. In the conclusion, a measurement report is mentioned. The standard requirements for the position of dowels and tie bars cover maximum possible deviation of the rebar position from the project documentation in vertical and horizontal direction, maximum deflection of rebar ends to each other, and maximum translation of rebar in the direction of its longitudinal axis.

  14. 2D and 3D Ground Penetrating Radar monitoring of a reinforced concrete asphalt plate affected by mechanical deformation.

    Science.gov (United States)

    Bavusi, M.; Dumoulin, J.; Loperte, A.; Rizzo, E.; Soldovieri, F.

    2012-04-01

    The main facility of Hydrogeosite Laboratory of the Italian National Research Council (Marsico Nuovo, CNR) is a 3m x 7m x 10m reinforced concrete pool filled by siliceous sand designed for hydrologic experiments. One of its peculiarities is the possibility to vary the water table depth by using a proper hydraulic system [1]. In the framework of the FP7 ISTIMES project (Integrated System for Transport Infrastructure surveillance and Monitoring by Electromagnetic Sensing), a 3m x 3m layered structure has been purposely built and placed in the pool of the Hydrogeosite Laboratory with the aim to carry out a long term monitoring, by using jointly several electromagnetic sensing technologies, during two different phases simulating the rising of the water table and a mechanical solicitation. Several layers composed the structure from the top to the bottom, such as: 5 cm of asphalt; 5-10 cm of reinforced concrete; 20-25 cm of conglomerate, 55 cm of sand. Moreover, in the sand layer, three (metallic and plastic) pipes of different size were buried to simulate utilities. Ground Penetrating Radar (GPR) surveys were performed by using a the GSSI SIR 3000 system equipped with 400 MHz and 1500 MHz central frequency antennas. Surveys carried out by means of 400 MHz antenna allowed to detect and localize the three pipes (one in plastic and two in metal) and to investigate the effects of the sand water content on their radar signature. Surveys carried out by using 1500 MHz antenna were focused to characterize the shallower layers of the structure. The Hydrogeosite experiment consisted in following stages: • Arising of a water table by infiltration from the bottom; • Water gravity infiltration condescendingly; • Infiltration by peristaltic pump in the very shallow layers of the structure; • Water table drawdown; • Mechanical structure deformation; • Asphalt plate restoration after mechanical solicitation. After each stage a series of GPR surveys was performed. Moreover

  15. Mapping a Pristine Glaciofluvial Aquifer on the Canadian Shield Using Ground-Penetrating Radar and Electrical Resistivity Tomography

    Science.gov (United States)

    Graves, L. W.; Shirokova, V.; Bank, C.

    2013-12-01

    Our study aims to construct a 3D structural model of an unconfined pristine aquifer in Laurentian Hills, Ontario, Canada. The stratigraphy of the study site, which covers about 5400 square meters, features reworked glaciofluvial sands and glacial till on top of Canadian Shield bedrock. A network of 25 existing piezometers provides ground-truth. We used two types of geophysical surveys to map the water table and the aquifer basin. Ground-penetrating radar (GPR) collected 40 profiles over distances up to 140 meters using 200MHz and 400MHz antennas with a survey wheel. The collected radargrams show a distinct reflective layer, which can be mapped to outcrops of glacial till within the area. This impermeable interface forms the aquitard. Depths of the subsurface features were calculated using hyperbolic fits on the radargrams in Matlab by determining wave velocity then converting measured two-way-time to depth. Electrical resistivity was used to determine the water table elevations because the unconfined water table did not reflect the radar waves. 20 resistivity profiles were collected in the same area using Wenner-Alpha and dipole-dipole arrays with both 24 and 48 electrodes and for 0.5, 0.75, 1.0 and 2.0 meter spacing. The inverted resistivity models show low resistivity values (resistivity values (2000-6000 Ohm.m) above 1 to 2 meter depths. These contrasting resistivity values correspond to saturated and wet sand (lower resistivity) to dry sand (higher resistivity); a correlation we could verify with several bore-hole logs. The water table is marked on the resistivity profiles as a steep resistivity gradient, and the depth can be added to the comprehensive 3D model. This model also incorporates hydrogeological characteristics and geochemical anomalies found within the aquifer. Ongoing seasonal and annual monitoring of the aquifer using geophysical methods will bring a fourth dimension to our understanding of this dynamic system. GPR Profile with Glacial Till

  16. Geophysical Field Work for Educators: Teachers Use Ground-Penetrating Radar to Study San Jacinto Battlefield Park

    Science.gov (United States)

    Henning, A. T.; Sawyer, D. S.; Milliken, K.

    2008-12-01

    In July 2008, a group of Houston area K-12 teachers investigated San Jacinto Battlefield Park in La Porte, Texas, utilizing ground-penetrating radar (GPR) to image the subsurface and global positioning system (GPS) units to map surface features. Participants were in-service K-12 teachers from urban Houston school districts where the majority of students are members of historically underrepresented minority groups. Over a period of two weeks, participants acquired and interpreted GPR profiles in the park, mapped surface features using hand-held GPS units, and analyzed the data using ArcGIS software. This summer experience was followed by a content-intensive academic year course in Earth Science. The Battle of San Jacinto took place on April 21, 1836, and was the decisive battle in the Texas Revolution. The site is thought to contain numerous in-situ artifacts dropped by the Texan and Mexican armies, as well as unmarked burials from the early 1800's. Two stratigraphic units were identified from the GPR profiles and matched to strata exposed through archaeological excavations. The stratigraphic units are interpreted as recent flood/storm deposits with soil formation on Pleistocene deltaic deposits of a previous sea-level highstand. In addition to the stratigraphy, a number of isolated subsurface anomalies (possibly artifacts) were identified. Participants also interpreted past shoreline positions using vintage aerial photographs and acquired several transects of GPS positions along the shoreline. Participants confirmed that the area is in fact subsiding, rather than being eroded. Participants not only experienced the scientific process but also utilized geophysics for community service (i.e. contributing educational material to the park). Through background research, they derived a rich historical context for their investigation and learned to appreciate the multi-disciplinary aspect of solving real- world scientific problems.

  17. Ground-penetrating radar (GPR) responses for sub-surface salt contamination and solid waste: modeling and controlled lysimeter studies.

    Science.gov (United States)

    Wijewardana, Y N S; Shilpadi, A T; Mowjood, M I M; Kawamoto, K; Galagedara, L W

    2017-02-01

    The assessment of polluted areas and municipal solid waste (MSW) sites using non-destructive geophysical methods is timely and much needed in the field of environmental monitoring and management. The objectives of this study are (i) to evaluate the ground-penetrating radar (GPR) wave responses as a result of different electrical conductivity (EC) in groundwater and (ii) to conduct MSW stratification using a controlled lysimeter and modeling approach. A GPR wave simulation was carried out using GprMax2D software, and the field test was done on two lysimeters that were filled with sand (Lysimeter-1) and MSW (Lysimeter-2). A Pulse EKKO-Pro GPR system with 200- and 500-MHz center frequency antennae was used to collect GPR field data. Amplitudes of GPR-reflected waves (sub-surface reflectors and water table) were studied under different EC levels injected to the water table. Modeling results revealed that the signal strength of the reflected wave decreases with increasing EC levels and the disappearance of the subsurface reflection and wave amplitude reaching zero at higher EC levels (when EC >0.28 S/m). Further, when the EC level was high, the plume thickness did not have a significant effect on the amplitude of the reflected wave. However, it was also found that reflected signal strength decreases with increasing plume thickness at a given EC level. 2D GPR profile images under wet conditions showed stratification of the waste layers and relative thickness, but it was difficult to resolve the waste layers under dry conditions. These results show that the GPR as a non-destructive method with a relatively larger sample volume can be used to identify highly polluted areas with inorganic contaminants in groundwater and waste stratification. The current methods of MSW dumpsite investigation are tedious, destructive, time consuming, costly, and provide only point-scale measurements. However, further research is needed to verify the results under heterogeneous aquifer

  18. Estimation of the near surface soil water content during evaporation using air-launched ground-penetrating radar

    KAUST Repository

    Moghadas, Davood

    2014-01-01

    Evaporation is an important process in the global water cycle and its variation affects the near sur-face soil water content, which is crucial for surface hydrology and climate modelling. Soil evaporation rate is often characterized by two distinct phases, namely, the energy limited phase (stage-I) and the soil hydraulic limited period (stage-II). In this paper, a laboratory experiment was conducted using a sand box filled with fine sand, which was subject to evaporation for a period of twenty three days. The setup was equipped with a weighting system to record automatically the weight of the sand box with a constant time-step. Furthermore, time-lapse air-launched ground penetrating radar (GPR) measurements were performed to monitor the evaporation process. The GPR model involves a full-waveform frequency-domain solution of Maxwell\\'s equations for wave propagation in three-dimensional multilayered media. The accuracy of the full-waveform GPR forward modelling with respect to three different petrophysical models was investigated. Moreover, full-waveform inversion of the GPR data was used to estimate the quantitative information, such as near surface soil water content. The two stages of evaporation can be clearly observed in the radargram, which indicates qualitatively that enough information is contained in the GPR data. The full-waveform GPR inversion allows for accurate estimation of the near surface soil water content during extended evaporation phases, when a wide frequency range of GPR (0.8-5.0 GHz) is taken into account. In addition, the results indicate that the CRIM model may constitute a relevant alternative in solving the frequency-dependency issue for full waveform GPR modelling.

  19. Improving soil moisture profile reconstruction from ground-penetrating radar data: a maximum likelihood ensemble filter approach

    Directory of Open Access Journals (Sweden)

    A. P. Tran

    2013-07-01

    Full Text Available The vertical profile of shallow unsaturated zone soil moisture plays a key role in many hydro-meteorological and agricultural applications. We propose a closed-loop data assimilation procedure based on the maximum likelihood ensemble filter algorithm to update the vertical soil moisture profile from time-lapse ground-penetrating radar (GPR data. A hydrodynamic model is used to propagate the system state in time and a radar electromagnetic model and petrophysical relationships to link the state variable with the observation data, which enables us to directly assimilate the GPR data. Instead of using the surface soil moisture only, the approach allows to use the information of the whole soil moisture profile for the assimilation. We validated our approach through a synthetic study. We constructed a synthetic soil column with a depth of 80 cm and analyzed the effects of the soil type on the data assimilation by considering 3 soil types, namely, loamy sand, silt and clay. The assimilation of GPR data was performed to solve the problem of unknown initial conditions. The numerical soil moisture profiles generated by the Hydrus-1D model were used by the GPR model to produce the "observed" GPR data. The results show that the soil moisture profile obtained by assimilating the GPR data is much better than that of an open-loop forecast. Compared to the loamy sand and silt, the updated soil moisture profile of the clay soil converges to the true state much more slowly. Decreasing the update interval from 60 down to 10 h only slightly improves the effectiveness of the GPR data assimilation for the loamy sand but significantly for the clay soil. The proposed approach appears to be promising to improve real-time prediction of the soil moisture profiles as well as to provide effective estimates of the unsaturated hydraulic properties at the field scale from time-lapse GPR measurements.

  20. Development of tongue-shaped and multilobate rock glaciers in alpine environments - Interpretations from ground penetrating radar surveys

    Science.gov (United States)

    Degenhardt, John J., Jr.

    2009-08-01

    Rock glaciers occur as lobate or tongue-shaped landforms composed of mixtures of poorly sorted, angular to blocky rock debris and ice. These landforms serve as primary sinks for ice and water storage in mountainous areas and represent transitional forms in the debris transport system, accounting for ~ 60% of all mass transport in some alpine regions. Observations of active (flowing) alpine rock glaciers indicate a common association between the debris that originates from cirque headwalls and the depositional lobes that comprise them. The delivery of this debris to the rock glacier is regulated primarily by the rate of headwall erosion and the point of origin of debris along the headwall. These factors control the relative movement of individual depositional lobes as well as the overall rate of propagation of a rock glacier. In recent geophysical studies, a number of alpine rock glaciers on Prins Karls Forland and Nordenskiöldland, Svalbard, Norway, and the San Juan Mountains of southwest Colorado, USA, have been imaged using ground penetrating radar (GPR) to determine if a relationship exists between the internal structure and surface morphology. Results indicate that the overall morphologic expression of alpine rock glaciers is related to lobate deposition during catastrophic episodes of rockfall that originated from associated cirque headwalls. Longitudinal GPR profiles from alpine rock glaciers examined in this study suggests that the difference in gross morphology between the lobate and tongue-shaped rock glaciers can be attributed primarily (but not exclusively) to cirque geometry, frequency and locations of debris discharge within the cirque, and the trend and magnitude of valley gradient in relation to cirque orientation. Collectively, these factors determine the manner in which high magnitude debris discharges, which seem to be the primary mechanism of formation, accumulate to form these rock glaciers.

  1. Improving ground-penetrating radar data in sedimentary rocks using deterministic deconvolution

    Science.gov (United States)

    Xia, J.; Franseen, E.K.; Miller, R.D.; Weis, T.V.; Byrnes, A.P.

    2003-01-01

    Resolution is key to confidently identifying unique geologic features using ground-penetrating radar (GPR) data. Source wavelet "ringing" (related to bandwidth) in a GPR section limits resolution because of wavelet interference, and can smear reflections in time and/or space. The resultant potential for misinterpretation limits the usefulness of GPR. Deconvolution offers the ability to compress the source wavelet and improve temporal resolution. Unlike statistical deconvolution, deterministic deconvolution is mathematically simple and stable while providing the highest possible resolution because it uses the source wavelet unique to the specific radar equipment. Source wavelets generated in, transmitted through and acquired from air allow successful application of deterministic approaches to wavelet suppression. We demonstrate the validity of using a source wavelet acquired in air as the operator for deterministic deconvolution in a field application using "400-MHz" antennas at a quarry site characterized by interbedded carbonates with shale partings. We collected GPR data on a bench adjacent to cleanly exposed quarry faces in which we placed conductive rods to provide conclusive groundtruth for this approach to deconvolution. The best deconvolution results, which are confirmed by the conductive rods for the 400-MHz antenna tests, were observed for wavelets acquired when the transmitter and receiver were separated by 0.3 m. Applying deterministic deconvolution to GPR data collected in sedimentary strata at our study site resulted in an improvement in resolution (50%) and improved spatial location (0.10-0.15 m) of geologic features compared to the same data processed without deterministic deconvolution. The effectiveness of deterministic deconvolution for increased resolution and spatial accuracy of specific geologic features is further demonstrated by comparing results of deconvolved data with nondeconvolved data acquired along a 30-m transect immediately adjacent

  2. Evaluating some factors that affect feasility of using ground penetrating radar for landmine detection

    Science.gov (United States)

    Metwaly, Mohamed; Ismail, Ahmed; Matsushima, Jun

    2007-09-01

    Ground penetrating radar (GPR) is one of the promising technologies that can be used to detect landmines. Many factors may affect the ability of GPR to detect landmines. Among those factors are: 1) the type of landmine material (metallic or plastic), 2) conditions of the host soil (soil texture and soil moisture), and 3) the radar frequency utilized. The impact of these factors on the ability of GPR to detect landmines is investigated by studying their effect on the dielectric permittivity contrast between the landmine and the host soil, as well as on the attenuation of the radar waves. The impact of each factor was theoretically reviewed and modeled using the Matlab and Mathcad software packages. Results of the computer modeling were correlated with GPR data acquired for metallic and plastic landmine types. It was found that the ability of GPR to detect landmines depends to a great extent on the landmine type, water content of the host soil, utilized radar frequency, and soil texture. The landmines are much easier to detect than plastic landmines for any soil conditions and any radar frequency. Increasing the soil’s moisture content, regardless of soil texture, eases the detection of the plastic landmine and worsens the detection of the metallic mines. Increasing the percentage of clay in the soil causes the same effect as the moisture content. However, higher radar frequency delivers better results for landmine detection as long as the percentage of clay and the moisture content in the soil remains low. The results of this study are expected to help in selecting optimum radar antennae and data acquisition parameters depending on the landmine type and environmental conditions.

  3. Observations on syntactic landmine detection using impulse ground-penetrating radar

    Science.gov (United States)

    Nasif, Ahmed O.; Hintz, Kenneth J.

    2011-06-01

    We discuss some results and observations on applying syntactic pattern recognition (SPR) methodology for landmine detection using impulse ground-penetrating radar (GPR). In the SPR approach, the GPR A-scans are first converted into binary-valued strings by inverse filtering, followed by concavity detection to identify the peaks and valleys representing the locations of impedance discontinuities in the return signal. During the training phase, the characteristic binary strings for a particular landmine are found by looking at all the exemplars of that mine and selecting the collection of strings that yield the best detection results on these exemplars. These characteristic strings can be detected very efficiently using finite state machines (FSMs). Finally, the FSM detections are clustered to assign confidence to each detection, and discard sparse detections. Provided that the impulse GPR provides enough resolution in range, the SPR method can be a robust and high-speed solution for landmine detection and classification, because it aims to exploit the impedance discontinuity profile of the target, which is a description of the internal material structure of the target and little affected by external clutter. To evaluate the proposed methodology, the SPR scheme is applied to a set of impulse GPR data taken at a government test site. We suggest that coherent frequency-agile radar may be a better option for the SPR approach, since it addresses some of the drawbacks of a non-coherent impulse GPR caused by internally non-coherent within-channel signals which necessitate non-coherent integration and its attendant longer integration times, and non-coherent adjacent channels which severely limit the ability to do spatial, or at a minimum, cross-range processing if the GPR is in a linear array antenna.

  4. Groundwater Surface Trends at Van Norden Meadow, California, from Ground Penetrating Radar Profiles

    Science.gov (United States)

    Tadrick, N. I.; Blacic, T. M.; Yarnell, S. M.

    2014-12-01

    Van Norden meadow in the Donner Summit area west of Lake Tahoe is one of the largest sub-alpine meadows in the Sierra Nevada mountain range. As natural water retention basins, meadows attenuate floods, improve water quality and support vegetation that stabilizes stream banks and promotes high biodiversity. Like most meadows in the Sierras however, over-grazing, road-building, and development has resulted in localized stream incision, degradation, and partial conversion from wet to dry conditions in Van Norden. Additionally, a small dam at the base of the meadow has partially flooded the lower meadow creating reservoir conditions. Privately owned since the late 1800s, Van Norden was recently purchased by a local land trust to prevent further development and return the area to public ownership. Restoration of the natural meadow conditions will involve notching the dam in 2016 to reduce currently impounded water volumes from 250 to less than 50 acre-feet. To monitor the effects of notching the dam on the upstream meadow conditions, better understanding of the surface and groundwater hydrology both pre- and post-restoration is required. We surveyed the meadow in summer 2014 with ground penetrating radar (GPR) to map the groundwater surface prior to restoration activities using a 270MHz antenna to obtain a suite of longitudinal and transverse transects. Groundwater level within the meadow was assessed using both piezometer readings and sweeps of the GPR antenna. Seventeen piezometers were added this year to the 13 already in place to monitor temporal changes in the groundwater surface, while the GPR profiles provided information about lateral variations. Our results provide an estimate of the groundwater depth variations across the upper portion of the meadow before notching. We plan to return in 2015 to collect GPR profiles during wetter conditions, which will provide a more complete assessment of the pre-notching groundwater hydrology.

  5. Estimating Trapped Gas Concentrations as Bubbles Within Lake Ice Using Ground Penetrating Radar

    Science.gov (United States)

    Fantello, N.; Parsekian, A.; Walter Anthony, K. M.

    2015-12-01

    Climate warming is currently one of the most important issues that we are facing. The degradation of permafrost beneath thermokarst lakes has been associated with enhanced methane emissions and it presents a positive feedback to climate warming. Thermokarst lakes release methane to the atmosphere mainly by ebullition (bubbling) but there are a large number of uncertainties regarding the magnitude and variability of these emissions. Here we present a methodology to estimate the amount of gas released from thermokarst lakes through ebullition using ground-penetrating radar (GPR). This geophysical technique is well suited for this type of problem because it is non-invasive, continuous, and requires less effort and time than the direct visual inspection. We are studying GPR data collected using 1.2 GHz frequency antennas in Brooklyn Lake, Laramie, WY, in order to quantify the uncertainties in the method. Although this is not a thermokarst lake, gas bubbles are trapped in the ice and spatial variability in bubble concentration within the ice is evident. To assess the variability in bulk physical properties of the ice due to bubbles, we gathered GPR data from different types of ice. We compared the velocity of the groundwave and reflection obtained from radargrams, and found on each case a larger value for the groundwave velocity suggesting a non-homogeneous medium and that the concentration of bubbles is prone to be near the surface instead of at greater depths. We use a multi-phase dielectric-mixing model to estimate the amount of gas present in a sample of volume of ice and found an uncertainty in relative permittivity (estimated using reflection velocity) of 0.0294, which translates to an uncertainty of 1.1% in gas content; and employing groundwave velocity we found 0.0712 and 2.9%, respectively. If locations of gas seeps in lakes could be detected and quantified using GPR along with field measurements, this could help to constrain future lake-source carbon gas

  6. Delineation of a landfill leachate plume using shallow electromagnetic and ground-penetrating radar surveys

    Energy Technology Data Exchange (ETDEWEB)

    Nobes, D.C.; Armstrong, M.J. [Univ. of Canterbury, Christchurch (New Zealand); Broadbent, M. [Broadbent (Michael), Christchurch (New Zealand)

    1994-12-31

    Leachate plumes are often more electrically conductive than the surrounding host pore waters, and thus can be detected using shallow electromagnetic (EM) methods. The depth of penetration of ground penetrating radar (GPR) is controlled to a large extent by the electrical conductivity. Conductive leachate plumes will appear as ``blank`` areas in the radar profiles, because the radar energy is more severely attenuated in the region of the leachate plume. The authors present here the results of EM and GPR Surveys carried out in an area adjacent to a landfill site. Previous resistivity surveys indicated the presence of a leachate plume originating from an early stage of the landfill operation. The shallow EM and GPR surveys were carried out, in part, to confirm and refine the resistivity results, and to delineate the spatial extent of the plume. The surficial sediments are coastal sands, and the dune topography has an effect on the EM results, even though the variations in elevation are, in general, no more than 3 m. Besides the leachate plume, numerous conductivity highs and lows are present, which are at least coarsely correlated with topographic lows and highs. Following the empirical procedure outlined by Monier-Williams et al. (1990), the topographic effects have been removed, and the plume is better isolated and delineated. A possible second, weaker leachate plume has been identified, emanating from the current landfill operation. The second plume may follow a channel that was masked by the overlying dune sands. The leading edge of the primary leachate plume is moving to the south-southeast at a rate of 14 to 15 m/yr.

  7. Condition assessment of concrete pavements using both ground penetrating radar and stress-wave based techniques

    Science.gov (United States)

    Li, Mengxing; Anderson, Neil; Sneed, Lesley; Torgashov, Evgeniy

    2016-12-01

    Two stress-wave based techniques, ultrasonic surface wave (USW) and impact echo (IE), as well as ground penetrating radar (GPR) were used to assess the condition of a segment of concrete pavement that includes a layer of concrete, a granular base and their interface. Core specimens retrieved at multiple locations were used to confirm the accuracy and reliability of each non-destructive testing (NDT) result. Results from this study demonstrate that the GPR method is accurate for estimating the pavement thickness and locating separations (air voids) between the concrete and granular base layers. The USW method is a rapid way to estimate the in-situ elastic modulus (dynamic elastic modulus) of the concrete, however, the existence of air voids at the interface could potentially affect the accuracy and reliability of the USW test results. The estimation of the dynamic modulus and the P-wave velocity of concrete was improved when a shorter wavelength range (3 in. to 8.5 in.) corresponding to the concrete layer thickness was applied instead of the full wavelength rage (3 in. to 11 in.) based on the standard spacing of the receiver transducers. The IE method is proved to be fairly accurate in estimating the thickness of concrete pavements. However, the flexural mode vibration could affect the accuracy and reliability of the test results. Furthermore, the existence of air voids between the concrete and granular base layers could affect the estimation of the compression wave velocity of concrete when the full wavelength range was applied (3 in. to 11 in.). Future work is needed in order to improve the accuracy and reliability of both USW and IE test results.

  8. Unlocking annual firn layer water equivalents from ground-penetrating radar data on an Alpine glacier

    Directory of Open Access Journals (Sweden)

    L. Sold

    2015-05-01

    Full Text Available The spatial representation of accumulation measurements is a major limitation for current glacier mass balance monitoring approaches. Here, we present a method for estimating annual accumulation rates on a temperate Alpine glacier based on the interpretation of internal reflection horizons (IRHs in helicopter-borne ground-penetrating radar (GPR data. For each individual GPR measurement, the signal travel time is combined with a simple model for firn densification and refreezing of meltwater. The model is calibrated at locations where GPR repeat measurements are available in two subsequent years and the densification can be tracked over time. Two 10.5 m long firn cores provide a reference for the density and chronology of firn layers. Thereby, IRHs correspond to density maxima, but not exclusively to former summer glacier surfaces. Along GPR profile sections from across the accumulation area we obtain the water equivalent (w.e. of several annual firn layers. Because deeper IRHs could be tracked over shorter distances, the total length of analysed profile sections varies from 7.3 km for the uppermost accumulation layer (2011 to 0.1 km for the deepest (i.e. oldest layer (2006. According to model results, refreezing accounts for 10% of the density increase over time and depth, and for 2% of the water equivalent. The strongest limitation to our method is the dependence on layer chronology assumptions. We show that GPR can be used not only to complement existing mass balance monitoring programmes on temperate glaciers but also to retrospectively extend newly initiated time series.

  9. A feature learning approach for classifying buried threats in forward looking ground penetrating radar data

    Science.gov (United States)

    Camilo, Joseph A.; Malof, Jordan M.; Collins, Leslie M.

    2016-05-01

    The forward-looking ground penetrating radar (FLGPR) is a remote sensing modality that has recently been investigated for buried threat detection. The FLGPR considered in this work uses stepped frequency sensing followed by filtered backprojection to create images of the ground, where each image pixel corresponds to the radar energy reflected from the subsurface at that location. Typical target detection processing begins with a prescreening operation where a small subset of spatial locations are chosen to consider for further processing. Image statistics, or features, are then extracted around each selected location and used for training a machine learning classification algorithm. A variety of features have been proposed in the literature for use in classification. Thus far, however, predominantly hand-crafted or manually designed features from the computer vision literature have been employed (e.g., HOG, Gabor filtering, etc.). Recently, it has been shown that image features learned directly from data can obtain state-of-the-art performance on a variety of problems. In this work we employ a feature learning scheme using k-means and a bag-of-visual-words model to learn effective features for target and non-target discrimination in FLGPR data. Experiments are conducted using several lanes of FLGPR data and learned features are compared with several previously proposed static features. The results suggest that learned features perform comparably, or better, than existing static features. Similar to other feature learning results, the features consist of edges or texture primitives, revealing which structures in the data are most useful for discrimination.

  10. Ground penetrating radar examination of thin tsunami beds - A case study from Phra Thong Island, Thailand

    Science.gov (United States)

    Gouramanis, Chris; Switzer, Adam D.; Polivka, Peter M.; Bristow, Charles S.; Jankaew, Kruawun; Dat, Pham T.; Pile, Jeremy; Rubin, Charles M.; Yingsin, Lee; Ildefonso, Sorvigenaleon R.; Jol, Harry M.

    2015-11-01

    Coastal overwash deposits from tsunamis and storms have been identified and characterised from many coastal environments. To date, these investigations have utilised ad-hoc time, energy and cost intensive invasive techniques, such as, pits and trenches or taking core samples. Here, we present the application of high-frequency ground penetrating radar (GPR) to identify and characterise the 2004 Indian Ocean Tsunami (IOT) and palaeotsunami deposits from Phra Thong Island, Thailand. This site is one of the most intensively studied palaeotsunami sites globally and preserves a series of late-Holocene stacked sandy tsunami deposits within an organic, muddy low-energy backbeach environment. Using 100, 500 and 1000 MHz GPR antennas, 29 reflection profiles were collected from two swales (X and Y) inland of the modern beach, and two common mid-point (CMP) profiles using the 200 MHz antennas were collected from Swale Y. Detailed examination of the CMPs allowed accurate velocity estimates to be applied to each profile. The reflection profiles included across-swale profiles and a high-resolution grid in Swale X, and were collected to investigate the feasibility of GPR to image the palaeotsunami deposits, and two profiles from Swale Y where the tsunami deposits are poorly known. The 500 MHz antennas provided the best stratigraphic resolution which was independently validated from the stratigraphy and sedimentology recovered from 17 auger cores collected along the profiles. It is clear from the augers and GPR data, that the different dielectric properties of the individual layers allow the identification of the IOT and earlier tsunami deposits on Phra Thong Island. Although applied in a coastal setting here, this technique can be applied to other environments where thin sand beds are preserved, in order to prioritise sites for detailed examination.

  11. Correlation between Resistivity and Ground Penetrating Radar (GPR) Methods in Understanding the Signatures in Detecting Cavities

    Science.gov (United States)

    Afiq Saharudin, Muhamad; Maslinda, Umi; Hisham, Hazrul; Taqiuddin, Z. M.; Nur Amalina, M. K. A.; Nawawi, Nordiana Ahmad; Sulaiman, Nabila; Nordiana, M. M.; Azwin, I. N.

    2017-04-01

    The research was conducted using Resistivity and Ground Penetrating Radar (GPR) methods in detecting in-filled cavities and air-filled cavities. The importance of this study is to see the difference in conductivity value of the in-filled and air-filled cavity. The first study location in which the known target is air-cavity located at School of Language, Literacies, and Translation (SoLLAT). The next study location is at Desasiswa Bakti Permai, which the known target is a bunker with both were located at Universiti Sains Malaysia, Penang and the last location is at Gua Musang, Kelantan with suspected in-filled cavity. The result from Gua Musang is compared with both of the results that have been done at Universiti Sains Malaysia. The resistivity value of the first location that indicates the possible tunnel is about 500 Ωm to 800 Ωm and the conductivity value is about 0.0017 S/m. The resistivity value for the second location located at Desasiswa Bakti Permai that indicates the bunker is about 50 Ωm to 250 Ωm and the conductivity value is about 0.1104 S/m. The resistivity value from Gua Musang is about 50 Ωm to 100 Ωm and the conductivity value is about 0.0101 S/m. The velocity of the in-filled cavities is much lower compared with the velocity of the air-filled cavities. Based on the characteristics, Gua Musang area was dominated with in-filled cavities.

  12. In situ characterization of forest litter using ground-penetrating radar

    Science.gov (United States)

    André, Frédéric; Jonard, François; Jonard, Mathieu; Lambot, Sébastien

    2016-03-01

    Decomposing litter accumulated on the soil surface in forests plays a major role in several ecosystem processes; its detailed characterization is therefore essential for thorough understanding of ecosystem functioning. In addition, litter is known to affect remote sensing radar data over forested areas and their proper processing requires accurate quantification of litter scattering properties. In the present study, ultrawideband (0.8-2.2 GHz) ground-penetrating radar (GPR) data were collected in situ for a wide range of litter types to investigate the potential of the technique to reconstruct litter horizons in undisturbed natural conditions. Radar data were processed resorting to full-wave inversion. Good agreement was generally found between estimated and measured litter layer thicknesses, with root-mean-square error values around 1 cm for recently fallen litter (OL layer) and around 2 cm for fragmented litter in partial decomposition (OF layer) and total litter (OL + OF). Nevertheless, significant correlations between estimated and measured thicknesses were found for total litter only. Inaccuracies in the reconstruction of the individual litter horizons were mainly attributed to weak dielectric contrasts amongst litter layers, with absolute differences in relative dielectric permittivity values often lower than 2 between humus horizons, and to uncertainties in the ground truth values. Radar signal inversions also provided reliable estimates of litter electromagnetic properties, with average relative dielectric permittivity values around 2.9 and 6.3 for OL and OF litters, respectively. These results are encouraging for the use of GPR for noninvasive characterization and mapping of forest litter. Perspectives for the application of the technique in biogeosciences are discussed.

  13. Soil properties and performance of landmine detection by metal detector and ground-penetrating radar — Soil characterisation and its verification by a field test

    Science.gov (United States)

    Takahashi, Kazunori; Preetz, Holger; Igel, Jan

    2011-04-01

    Metal detectors have commonly been used for landmine detection, and ground-penetrating radar (GPR) is about to be deployed for this purpose. These devices are influenced by the magnetic and electric properties of soil, since both employ electromagnetic techniques. Various soil properties and their spatial distributions were measured and determined with geophysical methods in four soil types where a test of metal detectors and GPR systems took place. By analysing the soil properties, these four soils were classified based on the expected influence of each detection technique and predicted soil difficulty. This classification was compared to the detection performance of the detectors and a clear correlation between the predicted soil difficulty and performance was observed. The detection performance of the metal detector and target identification performance of the GPR systems degraded in soils that were expected to be problematic. Therefore, this study demonstrated that the metal detector and GPR performance for landmine detection can be assessed qualitatively by geophysical analyses.

  14. Computational dynamics of acoustically driven microsphere systems.

    Science.gov (United States)

    Glosser, Connor; Piermarocchi, Carlo; Li, Jie; Dault, Dan; Shanker, B

    2016-01-01

    We propose a computational framework for the self-consistent dynamics of a microsphere system driven by a pulsed acoustic field in an ideal fluid. Our framework combines a molecular dynamics integrator describing the dynamics of the microsphere system with a time-dependent integral equation solver for the acoustic field that makes use of fields represented as surface expansions in spherical harmonic basis functions. The presented approach allows us to describe the interparticle interaction induced by the field as well as the dynamics of trapping in counter-propagating acoustic pulses. The integral equation formulation leads to equations of motion for the microspheres describing the effect of nondissipative drag forces. We show (1) that the field-induced interactions between the microspheres give rise to effective dipolar interactions, with effective dipoles defined by their velocities and (2) that the dominant effect of an ultrasound pulse through a cloud of microspheres gives rise mainly to a translation of the system, though we also observe both expansion and contraction of the cloud determined by the initial system geometry.

  15. Research on laser induced acoustic source based underwater communication system

    Science.gov (United States)

    Lei, Lihua; Zhou, Ju; Zhang, Lei; Wan, Xiaoyun

    2016-10-01

    Acoustic transducers are traditionally used to generate underwater acoustical energy with the device physically immersed in water. Novel methods are required for communicating from an in-air platform or surface vessel to a submerged vessel. One possible noncontact downlink communication system involves the use of laser induced acoustic source. The most common mechanisms of opto-acoustic energy conversion are, by order of increasing laser energy density and efficiency, thermal expansion, surface evaporation and optical breakdown. The laser induced acoustic source inherently bears the obvious advantage of not requiring any physical transducer in the medium. At the same time, acoustic energy propagation is efficient in water, whereas optical energy propagate well in air, leading to a more efficiency opto-acoustic communication method. In this paper, an opto-acoustic underwater Communication system is described, aiming to study and analysis whether laser induced sound could achieve good performance for effective communication in practical application.

  16. Characterization approaches using ground-penetrating radar and hydrological measurements in variably saturated porous media

    Science.gov (United States)

    Kowalsky, Michael Brendan

    Modeling the flow of water or the transport of contaminants through the subsurface requires the characterization of soil properties including permeability, porosity, and water retention. Such hydrological parameters are commonly heterogeneous, and uncertainty in their spatial distributions makes it difficult to construct hydrological models from only point measurements, which are commonly limited since their collection is expensive, time consuming and invasive. The application of geophysical methods offers a promising alternative for inferring hydrological properties in the subsurface. The focus of this dissertation is on a variety of applications of ground penetrating radar (GPR), a geophysical method that provides data non-invasively (or minimally invasively) with high spatial resolution and at low cost. While GPR data are increasingly used in shallow subsurface characterization, relations between such data and subsurface flow processes are poorly understood. The research presented in this dissertation stems from the need for (1) a better understanding of GPR data in relation to non-uniform and transient distributions of pore water, and (2) an approach relating GPR attributes, possibly in combination with additional data types, to hydrological parameters. An overview of GPR methods is given, including reviews of previous applications and of techniques for simulating GPR measurements, and is followed by a series of case studies. Comparison of real field data and simulations performed with an outcrop-derived model under various states of water saturation shows that the detectability of some sedimentary units depends on in-situ moisture conditions. Then, the simultaneous simulation of GPR surveys and transient flow shows that time-lapsed measurements offer information that might be useful for inferring hydrological parameter distributions in the vadose zone. An inverse technique is then presented which allows for the estimation of actual flow parameters using GPR

  17. The detectability of archaeological structures beneath the soil using the ground penetrating radar technique

    Science.gov (United States)

    Ferrara, C.; Barone, P. M.; Pajewski, L.; Pettinelli, E.; Rossi, G.

    2012-04-01

    The traditional excavation tools applied to Archaeology (i.e. trowels, shovels, bulldozers, etc.) produce, generally, a fast and invasive reconstruction of the ancient past. The geophysical instruments, instead, seem to go in the opposite direction giving, rapidly and non-destructively, geo-archaeological information. Moreover, the economic aspect should not be underestimated: where the former invest a lot of money in order to carry out an excavation or restoration, the latter spend much less to manage a geophysical survey, locating precisely the targets. Survey information gathered using non-invasive methods contributes to the creation of site strategies, conservation, preservation and, if necessary, accurate location of excavation and restoration units, without destructive testing methods, also in well-known archaeological sites [1]-[3]. In particular, Ground Penetrating Radar (GPR) has, recently, become the most important physical technique in archaeological investigations, allowing the detection of targets with both very high vertical and horizontal resolution, and has been successfully applied both to archaeological and diagnostic purposes in historical and monumental sites [4]. GPR configuration, antenna frequency and survey modality can be different, depending on the scope of the measurements, the nature of the site or the type of targets. Two-dimensional (2D) time/depth slices and radargrams should be generated and integrated with information obtained from other buried or similar artifacts to provide age, structure and context of the surveyed sites. In the present work, we present three case-histories on well-known Roman archaeological sites in Rome, in which GPR technique has been successfully used. To obtain 2D maps of the explored area, a bistatic GPR (250MHz and 500MHz antennas) was applied, acquiring data along several parallel profiles. The GPR results reveal the presence of similar circular anomalies in all the investigated archaeological sites. In

  18. Imaging Buried Culverts Using Ground Penetrating Radar: Comparing 100 MHZ Through 1 GHZ Antennae

    Science.gov (United States)

    Abdul Aziz, A.; Stewart, R. R.; Green, S. L.

    2013-12-01

    *Aziz, A A aabdulaziz@uh.edu Allied Geophysical Lab, Department of Earth and Atmospheric Sciences, University of Houston, TX, USA Stewart, R R rrstewart@uh.edu Allied Geophysical Lab, Department of Earth and Atmospheric Sciences, University of Houston, TX, USA *Green, S L slgreen@yahoo.com Allied Geophysical Lab, Department of Earth and Atmospheric Sciences, University of Houston, TX, USA A 3D ground penetrating radar (GPR) survey, using three different frequency antennae, was undertaken to image buried steel culverts at the University of Houston's La Marque Geophysical Observatory 30 miles south of Houston, Texas. The four culverts, under study, support a road crossing one of the area's bayous. A 32 m by 4.5 m survey grid was designed on the road above the culverts and data were collected with 100 MHz, 250 MHz, and 1 GHz antennae. We used an orthogonal acquisition geometry for the three surveys. Inline sampling was from 1.0 cm to 10 cm (from 1 GHz to 100 MHz antenna) with inline and crossline spacings ranging from 0.2 m to 0.5 m. We used an initial velocity of 0.1 m/ns (from previous CMP work at the site) for the display purposes. The main objective of the study was to analyze the effect of different frequency antennae on the resultant GPR images. We are also interested in the accuracy and resolution of the various images, in addition to developing an optimal processing flow.The data were initially processed with standard steps that included gain enhancement, dewow and temporal-filtering, background suppression, and 2D migration. Various radar velocities were used in the 2D migration and ultimately 0.12 m/ns was used. The data are complicated by multipathing from the surface and between culverts (from modeling). Some of this is ameliorated via deconvolution. The top of each of the four culverts was evident in the GPR images acquired with the 250 MHz and 100 MHz antennas. For 1 GHz, the top of the culvert was not clear due to the signal's attenuation. The 250 MHz

  19. Mapping Fractures in KAERI Underground Research Tunnel using Ground Penetrating Radar

    Science.gov (United States)

    Baek, Seung-Ho; Kim, Seung-Sep; Kwon, Jang-Soon

    2016-04-01

    The proportion of nuclear power in the Republic of Korea occupies about 40 percent of the entire electricity production. Processing or disposing nuclear wastes, however, remains one of biggest social issues. Although low- and intermediate-level nuclear wastes are stored temporarily inside nuclear power plants, these temporary storages can last only up to 2020. Among various proposed methods for nuclear waste disposal, a long-term storage using geologic disposal facilities appears to be most highly feasible. Geological disposal of nuclear wastes requires a nuclear waste repository situated deep within a stable geologic environment. However, the presence of small-scale fractures in bedrocks can cause serious damage to durability of such disposal facilities because fractures can become efficient pathways for underground waters and radioactive wastes. Thus, it is important to find and characterize multi-scale fractures in bedrocks hosting geologic disposal facilities. In this study, we aim to map small-scale fractures inside the KAERI Underground Research Tunnel (KURT) using ground penetrating radar (GPR). The KURT is situated in the Korea Atomic Energy Research Institute (KAERI). The survey target is a section of wall cut by a diamond grinder, which preserves diverse geologic features such as dykes. We conducted grid surveys on the wall using 500 MHz and 1000 MHz pulseEKKO PRO sensors. The observed GPR signals in both frequencies show strong reflections, which are consistent to form sloping planes. We interpret such planar features as fractures present in the wall. Such fractures were also mapped visually during the development of the KURT. We confirmed their continuity into the wall from the 3D GPR images. In addition, the spatial distribution and connectivity of these fractures are identified from 3D subsurface images. Thus, we can utilize GPR to detect multi-scale fractures in bedrocks, during and after developing underground disposal facilities. This study was

  20. Hidden faults in the Gobi Desert (Inner Mongolia, China) revealed by microtremor analysis, ground-penetrating radar and SQUID-supported transient electromagnetics

    Science.gov (United States)

    Rudersdorf, Andreas; Hölz, Sebastian; Torgoev, Almaz; Havenith, Hans-Balder; Reicherter, Klaus

    2013-04-01

    The endorheic Gaxun Nur Basin (GNB, also Ejina Basin, Hei river Basin, Ruoshui Basin) in the eastern Gobi desert is situated between the northern Tibetan Plateau and the Gobi Altai mountains. Recent fault activity is concentrated on the sinistral Altyn Tagh Fault, its eastern continuations and the Qilian Shan frontal thrust in the south, which are induced by the stress field of the India-Eurasia continental collision. In the north, the basin is bound by the Gobi Altai mountains with the major sinistral Gobi-Tien Shan Fault System. The basin is dominated by a very flat topography, active alluvial sedimentation from the south and eolian erosion by northwesterly winds. The basin formation and basement structure is poorly known. The sedimentary succession of up to 300 m thickness comprises intercalations of alluvial fan deposits, dune sands, lake sediments and playa evaporites. The latter tend to concentrate in the northern part of the basin, where the basin is limited by the Gobi Altai mountains. The top of the diversified successions and the Gobi surface itself is covered by gravels. Instrumental seismicity and paleoseismic records are rather low and earlier tectonic and paleoseismological investigations are sparse. We, therefore, conducted microtremor analyses and transient electromagnetics with a liquid nitrogen cooled SQUID magnetometer to reveal basement-basin interaction structures; ground-penetrating radar surveys were also carried out to investigate shallow reworking processes. First results show connections between subsurface data and a large-scale (>20 km long) lineament fingerprint from remote sensing studies. Here, we focus on a NW-SE striking lineament west of the city of Ejina, which shows only minor topographic evidence for fault activity. An earlier drill core nearby resulted in dating irregularities in the upper 60m, which are believed to be related to the lineament. Microtremor analysis shows a significant offset of the basement topography and ground-penetrating

  1. Secondary Metabolites of Industrial Applications (Wine, Confectionery, Tea Industry, Cosmetics, etc.: Detection of Truffes by Ground Penetrating Radar

    Directory of Open Access Journals (Sweden)

    A. AYDIN

    2014-06-01

    Full Text Available In recent years, Ground Penetration Radar (GPR is a relatively modern and effective and widely utilized technique for shallow subsurface exploration. The GPR technique was used to study the two-dimensional distribution of truffles on roots of oak trees in dry sediment soil and weathered limestone. We used A RAMAC system at 0.05 m intervals, and a signal frequency of 250 MHz for this study for showing the places of truffes on the researching profiles in the study area. To evaluate the efficiency of the GPR in the detection of truffes, this technique was tested on unknown area in the forest of Honaz mountain and a controlled study involving truffes that were buried at known depths. Honaz Mountain (Denizli-SW Turkey has a mild and humid climate and it produces a rich flora in the area. As a natural consequence thereof, the study area offers a rich mushroom potential that is a rising economic value. A large number of mushroom grooving areas have been detected during the study. The observed GPR data have been confirmed by the physical excavation. The study proposes that this method can be effectively employed to detect the natural mushrooms in the ground.The GPR was also tested for its ability to map position and types of the truffes underground in the field. We purposed that this study further confirmed that only truffes with diameters greater than 4 cm were detected by the GPR system. On the other hand, the formation of other roots bodies and their presence in soil might produce an anomaly in the soil, particularly at the interface between soil and truffle. To elucidate how the mushroom can reflect the signals, mineral composition of the mushrooms has been analysed. We showed that the percentages of K, Na, Ca, Mg, Fe, Al, P, S, Si, Cl minerals were significantly different from that of earth. This difference in element composition seems to cause the reflection of the signals. We can see on the GPR sections the truffles in the soil after they have

  2. Acoustic Test Results of Melamine Foam with Application to Payload Fairing Acoustic Attenuation Systems

    Science.gov (United States)

    Hughes, William O.; McNelis, Anne M.

    2014-01-01

    A spacecraft at launch is subjected to a harsh acoustic and vibration environment resulting from the passage of acoustic energy, created during the liftoff of a launch vehicle, through the vehicle's payload fairing. In order to ensure the mission success of the spacecraft it is often necessary to reduce the resulting internal acoustic sound pressure levels through the usage of acoustic attenuation systems. Melamine foam, lining the interior walls of the payload fairing, is often utilized as the main component of such a system. In order to better understand the acoustic properties of melamine foam, with the goal of developing improved acoustic attenuation systems, NASA has recently performed panel level testing on numerous configurations of melamine foam acoustic treatments at the Riverbank Acoustical Laboratory. Parameters assessed included the foam's thickness and density, as well as the effects of a top outer cover sheet material and mass barriers embedded within the foam. This testing followed the ASTM C423 standard for absorption and the ASTM E90 standard for transmission loss. The acoustic test data obtained and subsequent conclusions are the subjects of this paper.

  3. Ground penetrating radar study of a thickness of biogenic sediments in the vicinity of the Czechowskie Lake

    Science.gov (United States)

    Lamparski, Piotr

    2014-05-01

    The paper present results of investigations, which have made on a biogenic plain in the north-east part of the vicinity of the Czechowskie Lake. The basin of Lake Czechowskie occupies a deep depression located in the immediate hinterland of the maximum range of the Pomeranian Phase ice sheet in the northern part of Poland (Błaszkiewicz 2005). Drillings carried out within the peat plain in the western part of the lake basin indicate that there are relatively diversified lake sediments of up to 12 m in thickness. The ground penetrating radar profiling method (GPR) was used to determine a thickness of biogenic sediments. To tests was used GSS'I SIR SYSTEM-2000™ radar device with two antennae - the high resolution 400 MHz central frequency - for shallow prospecting of the subsurface layers and the low resolution 35 MHz - for determining the shape of the mineral bedrock. Overall, 33 GPR profiles was made all in all more than 3000 meters along and crosswise the longer axis of the biogenic plain. The range of radar penetration was set to 200 ns for 400 MHz antenna and 600 ns for the 35 MHz one, what is the equivalent respectively 4 m and 12,5 m in depth of biogenic sediments thickness. Horizontal scaling was made by GSSI survey wheel device. The thickness of biogenic sediments recognized by GPR reaches 10 meters only using 35 MHz antenna. In the case of the 400 MHz antenna, relatively high conductivity water-saturated peat and gyttia did not allow for the achievement of greater thickness than 3-4 meters testing. In a large part of the profiles was able to see the shape of the mineral bedrock in the form of a former lake basin. Also observed elevations and thresholds in the bedrock. Depth of the mineral deposits forming former lake bottom was confirmed by drillings. This study is a contribution to the Virtual Institute of Integrated Climate and Landscape Evolution Analysis -ICLEA- of the Helmholtz Association. References: Błaszkiewicz M, 2005. Późnoglacjalna i

  4. Semi-automatic template matching based extraction of hyperbolic signatures in ground-penetrating radar images

    Science.gov (United States)

    Sagnard, Florence; Tarel, Jean-Philippe

    2015-04-01

    In civil engineering applications, ground-penetrating radar (GPR) is one of the main non destructive technique based on the refraction and reflection of electromagnetic waves to probe the underground and particularly detect damages (cracks, delaminations, texture changes…) and buried objects (utilities, rebars…). An UWB ground-coupled radar operating in the frequency band [0.46;4] GHz and made of bowtie slot antennas has been used because, comparing to a air-launched radar, it increases energy transfer of electromagnetic radiation in the sub-surface and penetration depth. This paper proposes an original adaptation of the generic template matching algorithm to GPR images to recognize, localize and characterize with parameters a specific pattern associated with a hyperbola signature in the two main polarizations. The processing of a radargram (Bscan) is based on four main steps. The first step consists in pre-processing and scaling. The second step uses template matching to isolate and localize individual hyperbola signatures in an environment containing unwanted reflections, noise and overlapping signatures. The algorithm supposes to generate and collect a set of reference hyperbola templates made of a small reflection pattern in the vicinity of the apex in order to further analyze multiple time signals of embedded targets in an image. The standard Euclidian distance between the template shifted and a local zone in the radargram allows to obtain a map of distances. A user-defined threshold allows to select a reduced number of zones having a high similarity measure. In a third step, each zone is analyzed to detect minimum or maximum discrete amplitudes belonging to the first arrival times of a hyperbola signature. In the fourth step, the extracted discrete data (i,j) are fitted by a parametric hyperbola modeling based on the straight ray path hypothesis and using a constraint least square criterion associated with parameter ranges, that are the position, the

  5. Multi-offset ground-penetrating radar imaging of a lab-scale infiltration test

    Directory of Open Access Journals (Sweden)

    A. R. Mangel

    2012-11-01

    Full Text Available A lab scale infiltration experiment was conducted in a sand tank to evaluate the use of time-lapse multi-offset ground-penetrating radar (GPR data for monitoring dynamic hydrologic events in the vadose zone. Sets of 21 GPR traces at offsets between 0.44–0.9 m were recorded every 30 s during a 3 h infiltration experiment to produce a data cube that can be viewed as multi-offset gathers at unique times or common offset images, tracking changes in arrivals through time. Specifically, we investigated whether this data can be used to estimate changes in average soil water content during wetting and drying and to track the migration of the wetting front during an infiltration event. For the first problem we found that normal-moveout (NMO analysis of the GPR reflection from the bottom of the sand layer provided water content estimates ranging between 0.10–0.30 volumetric water content, which underestimated the value determined by depth averaging a vertical array of six moisture probes by 0.03–0.05 volumetric water content. Relative errors in the estimated depth to the bottom of the 0.6 m thick sand layer were typically on the order of 2%, though increased as high as 25% as the wetting front approached the bottom of the tank. NMO analysis of the wetting front reflection during the infiltration event generally underestimated the depth of the front with discrepancies between GPR and moisture probe estimates approaching 0.15 m. The analysis also resulted in underestimates of water content in the wetted zone on the order of 0.06 volumetric water content and a wetting front velocity equal to about half the rate inferred from the probe measurements. In a parallel modeling effort we found that HYDRUS-1D also underestimates the observed average tank water content determined from the probes by approximately 0.01–0.03 volumetric water content, despite the fact that the model was calibrated to the probe data. This error suggests that the assumed conceptual

  6. Delineating shallow Neogene deformation structures in northeastern Pará State using Ground Penetrating Radar

    Directory of Open Access Journals (Sweden)

    Dilce F. Rossetti

    2003-06-01

    Full Text Available The geological characterization of shallow subsurface Neogene deposits in northeastern Pará State using Ground Penetrating Radar (GPR revealed normal and reverse faults, as well as folds, not yet well documented by field studies. The faults are identified mostly by steeply-dipping reflections that sharply cut the nearby reflections causing bed offsets, drags and rollovers. The folds are recognized by reflections that are highly undulating, configuring broad concave and convex-up features that are up to 50 m wide and 80 to 90 ns deep. These deformation structures are mostly developed within deposits of Miocene age, though some of the faults might continue into younger deposits as well. Although the studied GPR sections show several diffractions caused by trees, differential degrees of moisture, and underground artifacts, the structures recorded here can not be explained by any of these ''noises''. The detailed analysis of the GPR sections reveals that they are attributed to bed distortion caused by brittle deformation and folding. The record of faults and folds are not widespread in the Neogene deposits of the Bragantina area. These GPR data are in agreement with structural models, which have proposed a complex evolution including strike-slip motion for this area from the Miocene to present.A caracterização geológica de depósitos neógenos ocorrentes em sub-superfície rasa no nordeste do Estado do Pará, usando Radar de Penetração no Solo (GPR, revelou a presença de falhas normais e reversas, bem como dobras, ainda não documentadas em estudos de campo prévios. As falhas são identificadas por reflexões inclinadas que cortam bruscamente reflexões vizinhas, causando freqüentes deslocamentos de camadas. As dobras são reconhecidas por reflexões fortemente ondulantes, configurando feições côncavas e convexas que medem até 50 m de amplitude e 80 a 90 m de profundidade. Estas estruturas deformacionais desenvolvem-se, principalmente

  7. Mars, accessing the third dimension: a software tool to exploit Mars ground penetrating radars data.

    Science.gov (United States)

    Cantini, Federico; Ivanov, Anton B.

    2016-04-01

    The Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS), on board the ESA's Mars Express and the SHAllow RADar (SHARAD), on board the NASA's Mars Reconnaissance Orbiter are two ground penetrating radars (GPRs) aimed to probe the crust of Mars to explore the subsurface structure of the planet. By now they are collecting data since about 10 years covering a large fraction of the Mars surface. On the Earth GPRs collect data by sending electromagnetic (EM) pulses toward the surface and listening to the return echoes occurring at the dielectric discontinuities on the planet's surface and subsurface. The wavelengths used allow MARSIS EM pulses to penetrate the crust for several kilometers. The data products (Radargrams) are matrices where the x-axis spans different sampling points on the planet surface and the y-axis is the power of the echoes over time in the listening window. No standard way to manage this kind of data is established in the planetary science community and data analysis and interpretation require very often some knowledge of radar signal processing. Our software tool is aimed to ease the access to this data in particular to scientists without a specific background in signal processing. MARSIS and SHARAD geometrical data such as probing point latitude and longitude and spacecraft altitude, are stored, together with relevant acquisition metadata, in a geo-enabled relational database implemented using PostgreSQL and PostGIS. Data are extracted from official ESA and NASA released data using self-developed python classes and scripts and inserted in the database using OGR utilities. This software is also aimed to be the core of a collection of classes and script to implement more complex GPR data analysis. Geometrical data and metadata are exposed as WFS layers using a QGIS server, which can be further integrated with other data, such as imaging, spectroscopy and topography. Radar geometry data will be available as a part of the iMars Web

  8. Scoria Cone and Tuff Ring Stratigraphy Interpreted from Ground Penetrating Radar, Rattlesnake Crater, Arizona

    Science.gov (United States)

    Kruse, S. E.; McNiff, C. M.; Marshall, A. M.; Courtland, L. M.; Connor, C.; Charbonnier, S. J.; Abdollahzadeh, M.; Connor, L.; Farrell, A. K.; Harburger, A.; Kiflu, H. G.; Malservisi, R.; Njoroge, M.; Nushart, N.; Richardson, J. A.; Rookey, K.

    2013-12-01

    Numerous recent studies have demonstrated that detailed investigation of scoria cone and maar morphology can reveal rich details the eruptive and erosion histories of these volcanoes. A suite of geophysical surveys were conducted to images Rattlesnake Crater in the San Francisco Volcanic Field, AZ, US. We report here the results of ~3.4 km of ground penetrating radar (GPR) surveys that target the processes of deposition and erosion on the pair of cinder cones that overprint the southeast edge of Rattlesnake crater and on the tuff ring that forms the crater rim. Data were collected with 500, 250, 100, and 50 MHz antennas. The profiles were run in a radial direction down the northeast flanks of the cones (~1 km diameter, ~120 meters height) , and on the inner and outer margins of the oblong maar rim (~20-80 meters height). A maximum depth of penetration of GPR signal of ~15m was achieved high on the flanks of scoria cones. A minimum depth of essentially zero penetration occurred in the central crater. We speculate that maximum penetration occurs near the peaks of the cones and crater rim because ongoing erosion limits new soil formation. Soil formation would tend to increase surface conductivity and hence decrease GPR penetration. Soil is probably better developed within the crater, precluding significant radar penetration there. On the northeast side of the gently flattened rim of the easternmost scoria cone, the GPR profile shows internal layering that dips ~20 degrees northeast relative to the current ground surface. This clearly indicates that the current gently dipping surface is not a stratigraphic horizon, but reflects instead an erosive surface into cone strata that formed close to the angle of repose. Along much of the cone flanks GPR profiles show strata dipping ~4-5 degrees more steeply than the current surface, suggesting erosion has occurred over most of the height of the cone. An abrupt change in strata attitude is observed at the gradual slope

  9. ISAT: The mega-fauna acoustic tracking system

    KAUST Repository

    De la Torre, Pedro

    2013-06-01

    The acoustic tracking module of the Integrated Satellite and Acoustic Telemetry (iSAT) system is discussed in detail. iSAT is capable of detecting the relative direction of an acoustic source by measuring the order of arrival (OOA) of the acoustic signal to each hydrophone in a triangular array. The characteristics of the hydrophones, the projector, and the target acoustic signal used for iSAT are described. Initially it is designed to study the movements of whale sharks (Rhincodon typus), but it could potentially be used to describe high resolution movements of other marine species. © 2013 IEEE.

  10. Acoustic Flow Monitor System - User Manual

    Science.gov (United States)

    LaHusen, Richard

    2005-01-01

    INTRODUCTION The Acoustic Flow Monitor (AFM) is a portable system that was designed by the U.S. Geological Survey Cascades Volcano Observatory to detect and monitor debris flows associated with volcanoes. It has been successfully used internationally as part of real-time warning systems in valleys threatened by such flows (Brantley, 1990; Marcial and others, 1996; Lavigne and others, 2000). The AFM system has also been proven to be an effective tool for monitoring some non-volcanic debris flows. This manual is intended to serve as a basic guide for the installation, testing, and maintenance of AFM systems. An overview of how the system works, as well as instructions for installation and guidelines for testing, is included. Interpretation of data is not covered in this manual; rather, the user should refer to the references provided for published examples of AFM data.

  11. Acoustic array systems theory, implementation, and application

    CERN Document Server

    Bai, Mingsian R; Benesty, Jacob

    2013-01-01

    Presents a unified framework of far-field and near-field array techniques for noise source identification and sound field visualization, from theory to application. Acoustic Array Systems: Theory, Implementation, and Application provides an overview of microphone array technology with applications in noise source identification and sound field visualization. In the comprehensive treatment of microphone arrays, the topics covered include an introduction to the theory, far-field and near-field array signal processing algorithms, practical implementations, and common applic

  12. Three Decades of Volume Change of a Small Greenlandic Glacier Using Ground Penetrating Radar, Structure from Motion, and Aerial Photogrammetry

    DEFF Research Database (Denmark)

    Marcer, M.; Stentoft, Peter Alexander; Bjerre, Elisa

    2017-01-01

    Glaciers in the Arctic are losing mass at an increasing rate. Here we use surface topography derived from Structure from Motion (SfM) and ice volume from ground penetrating radar (GPR) to describe the 2014 state of Aqqutikitsoq glacier (2.85 km) on Greenland's west coast. A photogrammetrically...... topography, the approach constitutes a viable alternative where the use of drones is not possible. Our investigations constitute the first glacier on Greenland's west coast where ice volume was determined and volume change calculated. The glacier's thinning rate is comparable to, for example, the Swiss Alps...

  13. Material Property Estimation for Direct Detection of DNAPL using Integrated Ground-Penetrating Radar Velocity, Imaging and Attribute Analysis

    Energy Technology Data Exchange (ETDEWEB)

    John H. Bradford; Stephen Holbrook; Scott B. Smithson

    2004-12-09

    The focus of this project is direct detection of DNAPL's specifically chlorinated solvents, via material property estimation from multi-fold surface ground-penetrating radar (GPR) data. We combine state-of-the-art GPR processing methodology with quantitative attribute analysis and material property estimation to determine the location and extent of residual and/or pooled DNAPL in both the vadose and saturated zones. An important byproduct of our research is state-of-the-art imaging which allows us to pinpoint attribute anomalies, characterize stratigraphy, identify fracture zones, and locate buried objects.

  14. The potentialities of ground-penetrating radar in the engineering geology using the radars GROT-12 and GROT-12E

    Science.gov (United States)

    Volkomirskaya, Liudmila; Gulevich, Oxana; Musalev, Dmitri

    2013-04-01

    The potentialities of ground-penetrating radar in the engineering geology using the radars GROT-12 and GROT-12E L.B. Volkomirskaya(1,2), O.A. Gulevich(1,2), D.N. Musalev(3) 1. IZMIRAN, 142190, Russia, Moscow, Troitsk, Kalugskoe 4 2. ZAO Timer, 142190, Russia, Moscow, Troitsk, Lesnaya str. 4B 3. OAO Belgorchemprom, Republic of Belarus, Minsk, Masherov str. 17 The article presents the potentialities of ground-penetrating radar in the engineering geology on the basis of the latest modifications of the GPR "GROT": the low-frequency GPR GROT-12 and the high-frequency GPR GROT-12E. The article gives technical specifications of the GPRs GROT-12 and GROT-12E and their particular characteristics that define them from analogues. The solutions of direct problems of ground penetrating radar on the basis of Maxwell's equations in general formulation with given wide-band signal source are confronted to experimental data received from different fields of the engineering geology, for example: 1. To secure mining in salt mines the method was adapted to locate in the working layers the investigating boreholes, fault lines, borders of displacement and blowout of productive layers, as well as working pits without access. 2. To monitor the reinforced concrete structures of airport runways the technology was worked out to collect and process GPR data so as to locate communications under the runways and examine basement condition. 3. To carry out the reconstruction of buildings and pre-project engineering geological works the GPR shooting technology was improved to process the examinations of the bearing capacity of soils and to locate lost communications. 4. To perform ecological monitoring of abandoned mines the technology of the GPR data collecting and processing was developed to assess the conditions of stowage materials in mouths of destroyed vertical mine shafts, the location of inclined mine shafts, the determination of hollow spaces and thinning zones, the localization of ground

  15. Three Decades of Volume Change of a Small Greenlandic Glacier Using Ground Penetrating Radar, Structure from Motion, and Aerial Photogrammetry

    DEFF Research Database (Denmark)

    Marcer, M.; Stentoft, Peter Alexander; Bjerre, Elisa

    2017-01-01

    Glaciers in the Arctic are losing mass at an increasing rate. Here we use surface topography derived from Structure from Motion (SfM) and ice volume from ground penetrating radar (GPR) to describe the 2014 state of Aqqutikitsoq glacier (2.85 km) on Greenland's west coast. A photogrammetrically...... topography, the approach constitutes a viable alternative where the use of drones is not possible. Our investigations constitute the first glacier on Greenland's west coast where ice volume was determined and volume change calculated. The glacier's thinning rate is comparable to, for example, the Swiss Alps...... and underlines that arctic glaciers are subject to fast changes....

  16. Identification of Acoustic-Vibratory System by Acoustic Measurement

    Directory of Open Access Journals (Sweden)

    Takuzo Iwatsubo

    1996-01-01

    Full Text Available A new method for reducing ill-conditioning in a class of identification problems is proposed. The key point of the method is that the identified vibration of the sound source is expressed as a superposition of vibration modes. The mathematical property of the coefficient matrix, the practical error expanding ratio, and the stochastic error expanding ratio are investigated in a numerical example. The mode-superposition method is shown to be an effective tool for acoustic-vibratory inverse analysis.

  17. Ground Penetrating Radar Profiles of Breached Anticlinal Ridges in the Northern Piedmont of the San Bernardino Mountains in Southern California

    Science.gov (United States)

    Bobyarchick, A. R.; Eppes, M. C.; Diemer, J. A.; Cathey, R. B.; Cottingham, M. A.; Eckardt, I. J.; Shiflet, J. E.; Waldron, A. J.

    2006-12-01

    The northern piedmont of the San Bernardino Mountains contains kinematic elements characteristic of the Mojave block dextral plate boundary zone between the North American and Pacific plates and the complex convergent Transverse Ranges partition of that motion here represented by the North Frontal thrust system. Predominantly lateral slip in the central Mojave block is carried by the Helendale fault through Lucerne Valley and southward to intersect the North Frontal thrust system in the San Bernardino Mountains. Active anticlinal flexures and partially emergent north-verging thrust faults have deformed Pleistocene alluvial fans and older rocks into east-trending ridges in the piedmont on both sides of the Helendale fault. The Cougar Buttes anticline underlies such a ridge east of the fault and is breached by contemporaneous orthogonal washes in several places along strike of the anticline. Greater relief occurs where the alluvial fans comprise carbonate- cemented soils and particularly resistant, prominent petrocalcic horizons. It is within these incised valleys that the sequence of Tertiary through Pleistocene deposits show that the asymmetric anticline is cored by a thrust fault. In order to examine more closely the fold-fault association in the Cougar Buttes anticline and suggest possible kinematic models, we conducted several ground penetrating radar (GPR) profiles at different levels across the ridge. Relatively superior relief in some washes allowed us to conduct profiles along the present topographic ridge crests (and thus along the crestal zone of the fold) and also along wash bottoms to provide profiles at the level of the fold's core. We used a GSSI SIR-3000 GPR system equipped with a monostatic 100 MHz antennae set to continuous recording mode; traverses over very irregular ground were done in point data mode. The system was set up with nominal high and low cutoff filters and automatic gain control, but we found that AGC overly amplified multiples or

  18. Acoustic CT system for temperature distribution measurement

    Institute of Scientific and Technical Information of China (English)

    Shinji Ohyama; Toyofumi Oga; Kazuo Oshima; Junya Takayama

    2008-01-01

    In this paper,a measurement method for crosssectional temperature distribution is addressed. A novel method based on an acoustic CT technique is proposed. Specifically,the temperature distributions are estimated using the time of flight data of several ultrasonic propagation paths. The times of the flight data contain both temperature and wind effect,and the method to select only temperature component is introduced. A filtered back projection method is applied to reconstruct the temperature distributions from the time of flight data. An experimental system was designed and fabricated to realize simultaneous temperature and wind velocity distribution measurements. Through this system,the effectiveness of the proposed measurement method is confirmed.

  19. Advancing Understanding of the Role of Belowground Processes in Terrestrial Carbon Sinks trhrough Ground-Penetrating Radar. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Day, Frank P. [Old Dominion Univ., Norfolk, VA (United States)

    2015-02-06

    Coarse roots play a significant role in belowground carbon cycling and will likely play an increasingly crucial role in belowground carbon sequestration as atmospheric CO2 levels continue to rise, yet they are one of the most difficult ecosystem parameters to quantify. Despite promising results with ground-penetrating radar (GPR) as a nondestructive method of quantifying biomass of coarse roots, this application of GPR is in its infancy and neither the complete potential nor limitations of the technology have been fully evaluated. The primary goals and questions of this study fell into four groups: (1) GPR methods: Can GPR detect change in root biomass over time, differentiate live roots from dead roots, differentiate between coarse roots, fine roots bundled together, and a fine root mat, remain effective with varied soil moisture, and detect shadowed roots (roots hidden below larger roots); (2) CO2 enrichment study at Kennedy Space Center in Brevard County, Florida: Are there post-fire legacy effects of CO2 fertilization on plant carbon pools following the end of CO2application ? (3) Disney Wilderness Study: What is the overall coarse root biomass and potential for belowground carbon storage in a restored longleaf pine flatwoods system? Can GPR effectively quantify coarse roots in soils that are wetter than the previous sites and that have a high percentage of saw palmetto rhizomes present? (4) Can GPR accurately represent root architecture in a three-dimensional model? When the user is familiar with the equipment and software in a setting that minimizes unsuitable conditions, GPR is a relatively precise, non-destructive, useful tool for estimating coarse root biomass. However, there are a number of cautions and guidelines that should be followed to minimize inaccuracies or situations that are untenable for GPR use. GPR appears to be precise as it routinely predicts highly similar values for a given area across multiple

  20. Developing ground penetrating radar (GPR) for enhanced root and soil organic carbon imaging: Optimizing bioenergy crop adaptation and agro-ecosystem services

    Science.gov (United States)

    Hays, D. B.; Delgado, A.; Bruton, R.; Dobreva, I. D.; Teare, B.; Jessup, R.; Rajan, N.; Bishop, M. P.; Lacey, R.; Neely, H.; Hons, F.; Novo, A.

    2016-12-01

    Selection of the ideal high biomass energy feedstock and crop cultivars for our national energy and production needs should consider not only the value of the harvested above ground feedstock, but also the local and global environmental services it provides in terms of terrestrial carbon (C) phyto-sequestration and improved soil organic matter enrichment. Selection of ideal crops cultivars is mature, while biofuel feedstock is well under way. What is lacking, however, is high throughput phenotyping (HTP) and integrated real-time data analysis technologies for selecting ideal genotypes within these crops that also confer recalcitrant high biomass or perennial root systems not only for C phyto-sequestration, but also for adaptation to conservation agro-ecosystems, increasing soil organic matter and soil water holding capacity. In no-till systems, significant studies have shown that increasing soil organic carbon is derived primarily from root and not above ground biomass. As such, efforts to increase plant soil phyto-sequestration will require a focus on developing optimal root systems within cultivated crops. We propose to achieve a significant advancement in the use of ground penetrating radar (GPR) as one approach to phenotype root biomass and 3D architecture, and to quantify soil carbon sequestration. In this context, GPR can be used for genotypic selection in breeding nurseries and unadapted germplasm with favorable root architectures, and for assessing management and nutrient practices that promote root growth. GPR has been used for over a decade to successfully map coarse woody roots. Only few have evaluated its efficacy for imaging finer fibrous roots found in grasses, or tap root species. The objectives of this project is to: i) Empirically define the optimal ground penetrating radar (GPR)-antenna array for 3D root and soil organic carbon imaging and quantification in high biomass grass systems; and ii) Develop novel 3- and 4-dimensional data analysis

  1. Electromechanical transducer for acoustic telemetry system

    Energy Technology Data Exchange (ETDEWEB)

    Drumheller, Douglas S. (Cedar Crest, NM)

    1993-01-01

    An improved electromechanical transducer is provided for use in an acoustic telemetry system. The transducer of this invention comprises a stack of ferroelectric ceramic disks interleaved with a plurality of spaced electrodes which are used to electrically pole the ceramic disks. The ceramic stack is housed in a metal tubular drill collar segment. The electrodes are preferably alternatively connected to ground potential and driving potential. This alternating connection of electrodes to ground and driving potential subjects each disk to an equal electric field; and the direction of the field alternates to match the alternating direction of polarization of the ceramic disks. Preferably, a thin metal foil is sandwiched between electrodes to facilitate the electrical connection. Alternatively, a thicker metal spacer plate is selectively used in place of the metal foil in order to promote thermal cooling of the ceramic stack.

  2. Electromechanical transducer for acoustic telemetry system

    Energy Technology Data Exchange (ETDEWEB)

    Drumheller, D.S.

    1993-06-22

    An improved electromechanical transducer is provided for use in an acoustic telemetry system. The transducer of this invention comprises a stack of ferroelectric ceramic disks interleaved with a plurality of spaced electrodes which are used to electrically pole the ceramic disks. The ceramic stack is housed in a metal tubular drill collar segment. The electrodes are preferably alternatively connected to ground potential and driving potential. This alternating connection of electrodes to ground and driving potential subjects each disk to an equal electric field; and the direction of the field alternates to match the alternating direction of polarization of the ceramic disks. Preferably, a thin metal foil is sandwiched between electrodes to facilitate the electrical connection. Alternatively, a thicker metal spacer plate is selectively used in place of the metal foil in order to promote thermal cooling of the ceramic stack.

  3. Detection of Underwater Military Munitions by a Synoptic Airborne Multi-Sensor System

    Science.gov (United States)

    2010-07-01

    passive and active sensing with knowledge-based information to create a detection system that is expected to be, in principle , orders of magnitude...existing technologies and their shortcomings include: • Synthetic-aperture ground-penetrating radar is of little use in estuarine and coastal soils...Optical-Acoustic UXO Detection Shearography is based on optical interferometry and takes advantage of the long coherence length of laser light to

  4. SYS 2: Acoustic ENSBox A System of Self Calibrating Distributed Acoustic Arrays

    OpenAIRE

    Lewis Girod; Martin Lukac; Vlad Trifa; Deborah Estrin

    2006-01-01

    The Acoustic Embedded Networked Sensing Box, is a platform for prototyping rapid-deployable distributed acoustic sensing systems, particularly distributed source localization. Each ENSBox integrates an ARM processor running Linux and supports key facilities required for source localization: a sensor array, wireless network services, time synchronization, and precise self-calibration of array position and orientation. The ENSBoxs integrated high precision self-calibration facility sets it ap...

  5. Temporal Monitoring of the Soil Freeze-Thaw Cycles over a Snow-Covered Surface by Using Air-Launched Ground-Penetrating Radar

    KAUST Repository

    Jadoon, Khan

    2015-09-18

    We tested an off-ground ground-penetrating radar (GPR) system at a fixed location over a bare agricultural field to monitor the soil freeze-thaw cycles over a snow-covered surface. The GPR system consisted of a monostatic horn antenna combined with a vector network analyzer, providing an ultra-wideband stepped-frequency continuous-wave radar. An antenna calibration experiment was performed to filter antenna and back scattered effects from the raw GPR data. Near the GPR setup, sensors were installed in the soil to monitor the dynamics of soil temperature and dielectric permittivity at different depths. The soil permittivity was retrieved via inversion of time domain GPR data focused on the surface reflection. Significant effects of soil dynamics were observed in the time-lapse GPR, temperature and dielectric permittivity measurements. In particular, five freeze and thaw events were clearly detectable, indicating that the GPR signals respond to the contrast between the dielectric permittivity of frozen and thawed soil. The GPR-derived permittivity was in good agreement with sensor observations. Overall, the off-ground nature of the GPR system permits non-invasive time-lapse observation of the soil freeze-thaw dynamics without disturbing the structure of the snow cover. The proposed method shows promise for the real-time mapping and monitoring of the shallow frozen layer at the field scale.

  6. Temporal Monitoring of the Soil Freeze-Thaw Cycles over a Snow-Covered Surface by Using Air-Launched Ground-Penetrating Radar

    Directory of Open Access Journals (Sweden)

    Khan Zaib Jadoon

    2015-09-01

    Full Text Available We tested an off-ground ground-penetrating radar (GPR system at a fixed location over a bare agricultural field to monitor the soil freeze-thaw cycles over a snow-covered surface. The GPR system consisted of a monostatic horn antenna combined with a vector network analyzer, providing an ultra-wideband stepped-frequency continuous-wave radar. An antenna calibration experiment was performed to filter antenna and back scattered effects from the raw GPR data. Near the GPR setup, sensors were installed in the soil to monitor the dynamics of soil temperature and dielectric permittivity at different depths. The soil permittivity was retrieved via inversion of time domain GPR data focused on the surface reflection. Significant effects of soil dynamics were observed in the time-lapse GPR, temperature and dielectric permittivity measurements. In particular, five freeze and thaw events were clearly detectable, indicating that the GPR signals respond to the contrast between the dielectric permittivity of frozen and thawed soil. The GPR-derived permittivity was in good agreement with sensor observations. Overall, the off-ground nature of the GPR system permits non-invasive time-lapse observation of the soil freeze-thaw dynamics without disturbing the structure of the snow cover. The proposed method shows promise for the real-time mapping and monitoring of the shallow frozen layer at the field scale.

  7. The use of Ground Penetrating Radar in coastal research, archeaological investigations, lake studies, peat layer measurments and applied research in Estonia

    Science.gov (United States)

    Vilumaa, Kadri; Tõnisson, Hannes; Orviku, Kaarel

    2014-05-01

    the volume of stored carbon in the lake). Additionally, we have done several archaeology-related research including the search of buried city walls and caves (Tallinn old town), buried Viking ship (Saaremaa Island) and several other archaeological objects. We have also done some applied studies including the search of underground power cables, heating pipes, melioration systems, ammunition warehouses (from World War II) and buried ammunition from the military training fields. Aknowledgement: The authors acknowledge COST for funding Action TU1208 'Civil Engineering Applications of Ground Penetrating Radar', supporting part of this work.

  8. High resolution shallow geologic characterization of a late Pleistocene eolian environment using ground penetrating radar and optically stimulated luminescence techniques: North Carolina, USA

    Science.gov (United States)

    Mallinson, D.; Mahan, S.; Moore, Christine

    2008-01-01

    Geophysical surveys, sedimentology, and optically-stimulated luminescence age analyses were used to assess the geologic development of a coastal system near Swansboro, NC. This area is a significant Woodland Period Native American habitation and is designated the "Broad Reach" archaeological site. 2-d and 3-d subsurface geophysical surveys were performed using a ground penetrating radar system to define the stratigraphic framework and depositional facies. Sediment samples were collected and analyzed for grain-size to determine depositional environments. Samples were acquired and analyzed using optically stimulated luminescence techniques to derive the depositional age of the various features. The data support a low eolian to shallow subtidal coastal depositional setting for this area. Li-DAR data reveal ridge and swale topography, most likely related to beach ridges, and eolian features including low-relief, low-angle transverse and parabolic dunes, blowouts, and a low-relief eolian sand sheet. Geophysical data reveal dominantly seaward dipping units, and low-angle mounded features. Sedimentological data reveal mostly moderately-well to well-sorted fine-grained symmetrical to coarse skewed sands, suggesting initial aqueous transport and deposition, followed by eolian reworking and bioturbation. OSL data indicate initial coastal deposition prior to ca. 45,000 yBP, followed by eolian reworking and low dune stabilization at ca. 13,000 to 11,500 yBP, and again at ca. 10,000 yBP (during, and slightly after the Younger Dryas chronozone).

  9. Archive of ground penetrating radar data collected during USGS field activity 13BIM01—Dauphin Island, Alabama, April 2013

    Science.gov (United States)

    Forde, Arnell S.; Smith, Christopher G.; Reynolds, Billy J.

    2016-03-18

    From April 13 to 20, 2013, scientists from the U.S. Geological Survey St. Petersburg Coastal and Marine Science Center (USGS-SPCMSC) conducted geophysical and sediment sampling surveys on Dauphin Island, Alabama, as part of Field Activity 13BIM01. The objectives of the study were to quantify inorganic and organic accretion rates in back-barrier and mainland marsh and estuarine environments. Various field and laboratory methods were used to achieve these objectives, including subsurface imaging using Ground Penetrating Radar (GPR), sediment sampling, lithologic and microfossil analyses, and geochronology techniques to produce barrier island stratigraphic cross sections to help interpret the recent (last 2000 years) geologic evolution of the island.This data series report is an archive of GPR and associated Global Positioning System (GPS) data collected in April 2013 from Dauphin Island and adjacent barrier-island environments. In addition to GPR data, marsh core and vibracore data were also collected collected but are not reported (or included) in the current report. Data products, including elevation-corrected subsurface profile images of the processed GPR data, unprocessed digital GPR trace data, post-processed GPS data, Geographic Information System (GIS) files and accompanying Federal Geographic Data Committee (FGDC) metadata, can be downloaded from the Data Downloads page.

  10. Imaging tropical peatlands in Indonesia using ground penetrating radar (GPR and electrical resistivity imaging (ERI: implications for carbon stock estimates and peat soil characterization

    Directory of Open Access Journals (Sweden)

    X. Comas

    2015-01-01

    Full Text Available Current estimates of carbon (C storage in peatland systems worldwide indicate tropical peatlands comprise about 15% of the global peat carbon pool. Such estimates are uncertain due to data gaps regarding organic peat soil thickness and C content. Indonesian peatlands are considered the largest pool of tropical peat carbon (C, accounting for an estimated 65% of all tropical peat while being the largest source of carbon dioxide emissions from degrading peat worldwide, posing a major concern regarding long-term sources of greenhouse gases to the atmosphere. We combined a set of indirect geophysical methods (ground penetrating radar, GPR, and electrical resistivity imaging, ERI with direct observations from core samples (including C analysis to better understand peatland thickness in West Kalimantan (Indonesia and determine how geophysical imaging may enhance traditional coring methods for estimating C storage in peatland systems. Peatland thicknesses estimated from GPR and ERI and confirmed by coring indicated variation by less than 3% even for small peat-mineral soil interface gradients (i.e. below 0.02°. The geophysical data also provide information on peat matrix attributes such as thickness of organomineral horizons between peat and underlying substrate, the presence of wood layers, buttressed trees and soil type. These attributes could further constrain quantification of C content and aid responsible peatland management in Indonesia.

  11. Imaging tropical peatlands in Indonesia using ground penetrating radar (GPR) and electrical resistivity imaging (ERI): implications for carbon stock estimates and peat soil characterization

    Science.gov (United States)

    Comas, X.; Terry, N.; Slater, L.; Warren, M.; Kolka, R.; Kristijono, A.; Sudiana, N.; Nurjaman, D.; Darusman, T.

    2015-01-01

    Current estimates of carbon (C) storage in peatland systems worldwide indicate tropical peatlands comprise about 15% of the global peat carbon pool. Such estimates are uncertain due to data gaps regarding organic peat soil thickness and C content. Indonesian peatlands are considered the largest pool of tropical peat carbon (C), accounting for an estimated 65% of all tropical peat while being the largest source of carbon dioxide emissions from degrading peat worldwide, posing a major concern regarding long-term sources of greenhouse gases to the atmosphere. We combined a set of indirect geophysical methods (ground penetrating radar, GPR, and electrical resistivity imaging, ERI) with direct observations from core samples (including C analysis) to better understand peatland thickness in West Kalimantan (Indonesia) and determine how geophysical imaging may enhance traditional coring methods for estimating C storage in peatland systems. Peatland thicknesses estimated from GPR and ERI and confirmed by coring indicated variation by less than 3% even for small peat-mineral soil interface gradients (i.e. below 0.02°). The geophysical data also provide information on peat matrix attributes such as thickness of organomineral horizons between peat and underlying substrate, the presence of wood layers, buttressed trees and soil type. These attributes could further constrain quantification of C content and aid responsible peatland management in Indonesia.

  12. Fusion of KLMS and blob based pre-screener for buried landmine detection using ground penetrating radar

    Science.gov (United States)

    Baydar, Bora; Akar, Gözde Bozdaǧi.; Yüksel, Seniha E.; Öztürk, Serhat

    2016-05-01

    In this paper, a decision level fusion using multiple pre-screener algorithms is proposed for the detection of buried landmines from Ground Penetrating Radar (GPR) data. The Kernel Least Mean Square (KLMS) and the Blob Filter pre-screeners are fused together to work in real time with less false alarms and higher true detection rates. The effect of the kernel variance is investigated for the KLMS algorithm. Also, the results of the KLMS and KLMS+Blob filter algorithms are compared to the LMS method in terms of processing time and false alarm rates. Proposed algorithm is tested on both simulated data and real data collected at the field of IPA Defence at METU, Ankara, Turkey.

  13. Random noise de-noising and direct wave eliminating based on SVD method for ground penetrating radar signals

    Science.gov (United States)

    Liu, Cai; Song, Chao; Lu, Qi

    2017-09-01

    In this paper, we present a method using singular value decomposition (SVD) which aims at eliminating the random noise and direct wave from ground penetrating radar (GPR) signals. To demonstrate the validity and high efficiency of the SVD method in eliminating random noise, we compare the SVD de-noising method with wavelet threshold de-noising method and bandpass filtering method on both noisy synthetic data and field data. After that, we compare the SVD method with the mean trace deleting in eliminating direct wave on synthetic data and field data. We set general and quantitative criteria on choosing singular values to carry out the random noise de-noising and direct wave eliminating process. We find that by choosing appropriate singular values, SVD method can eliminate the random noise and direct wave in the GPR data validly and efficiently to improve the signal-to-noise ratio (SNR) of the GPR profiles and make effective reflection signals clearer.

  14. Characteristics of ejecta and alluvial deposits at Meteor Crater, Arizona and Odessa Craters, Texas: Results from ground penetrating radar

    Science.gov (United States)

    Grant, J. A.; Schultz, P. H.

    1991-01-01

    Previous ground penetrating radar (GRP) studies around 50,000 year old Meteor Crater revealed the potential for rapid, inexpensive, and non-destructive sub-surface investigations for deep reflectors (generally greater than 10 m). New GRP results are summarized focusing the shallow sub-surfaces (1-2 m) around Meteor Crater and the main crater at Odessa. The following subject areas are covered: (1) the thickness, distribution, and nature of the contact between surrounding alluvial deposits and distal ejecta; and (2) stratigraphic relationships between both the ejecta and alluvium derived from both pre and post crater drainages. These results support previous conclusions indicating limited vertical lowering (less than 1 m) of the distal ejecta at Meteor Crater and allow initial assessment of the gradational state if the Odessa craters.

  15. Saturated hydraulic conductivity determined by on ground mono-offset Ground-Penetrating Radar inside a single ring infiltrometer

    CERN Document Server

    Léger, Emmanuel; Coquet, Yves

    2013-01-01

    In this study we show how to use GPR data acquired along the infiltration of water inside a single ring infiltrometer to inverse the saturated hydraulic conductivity. We used Hydrus-1D to simulate the water infiltration. We generated water content profiles at each time step of infiltration, based on a particular value of the saturated hydraulic conductivity, knowing the other van Genuchten parameters. Water content profiles were converted to dielectric permittivity profiles using the Complex Refractive Index Method relation. We then used the GprMax suite of programs to generate radargrams and to follow the wetting front using arrival time of electromagnetic waves recorded by a Ground-Penetrating Radar (GPR). Theoretically, the 1D time convolution between reflectivity and GPR signal at any infiltration time step is related to the peak of the reflected amplitude recorded in the corresponding trace in the radargram. We used this relation ship to invert the saturated hydraulic conductivity for constant and fallin...

  16. Ground-penetrating radar study of the Cena Bog, Latvia: linkage of reflections with peat moisture content

    Directory of Open Access Journals (Sweden)

    Karušs, J.

    2015-12-01

    Full Text Available Present work illustrates results of the ground-penetrating radar (GPR study of the Cena Bog, Latvia. Six sub-horizontal reflections that most probably correspond to boundaries between sediments with different electromagnetic properties were identified. One of the reflections corresponds to bog peat mineral bottom interface but the rest are linked to boundaries within the peat body. The radar profiles are incorporated with sediment cores and studies of peat moisture and ash content, and degree of decomposition. Most of the electromagnetic wave reflections are related to changes in peat moisture content. The obtained data show that peat moisture content changes of at least 3 % are required to cause GPR signal reflection. However, there exist reflections that do not correlate with peat moisture content. As a result, authors disagree with a dominant opinion that all reflections in bogs are solely due to changes in volumetric peat moisture content.

  17. Monitoring CO2 gas-phase migration in a shallow sand aquifer using cross-borehole ground penetrating radar

    DEFF Research Database (Denmark)

    Lassen, Rune Nørbæk; Sonnenborg, T.O.; Jensen, Karsten Høgh

    2015-01-01

    Understanding potential pathways of gaseous CO2 into and through the shallow subsurface from deep geological storage is one of many requirements related to risk assessment of a carbon capture and storage (CCS) site. In this study, a series of field experiments were carried out at a site located...... in Vrøgum in western Denmark. Up to 45 kg of gaseous CO2 was injected into a shallow aquifer approximately 8 m below the groundwater table. In the upper 6 m, the aquifer consisted of fine Aeolian sand underlain by coarser glacial sand. The migration of the gaseous CO2 was tracked using cross-borehole ground...... penetrating radar (GPR). A total of six GPR-boreholes were installed around the injection well and in the dominant flow direction of the groundwater. The GPR measurements were collected before, during, and after the CO2-injection. The GPR method proved to be very sensitive to desaturation of the aquifer when...

  18. Optimization of a Biometric System Based on Acoustic Images

    Science.gov (United States)

    Izquierdo Fuente, Alberto; Del Val Puente, Lara; Villacorta Calvo, Juan J.; Raboso Mateos, Mariano

    2014-01-01

    On the basis of an acoustic biometric system that captures 16 acoustic images of a person for 4 frequencies and 4 positions, a study was carried out to improve the performance of the system. On a first stage, an analysis to determine which images provide more information to the system was carried out showing that a set of 12 images allows the system to obtain results that are equivalent to using all of the 16 images. Finally, optimization techniques were used to obtain the set of weights associated with each acoustic image that maximizes the performance of the biometric system. These results improve significantly the performance of the preliminary system, while reducing the time of acquisition and computational burden, since the number of acoustic images was reduced. PMID:24616643

  19. Optimization of a Biometric System Based on Acoustic Images

    Directory of Open Access Journals (Sweden)

    Alberto Izquierdo Fuente

    2014-01-01

    Full Text Available On the basis of an acoustic biometric system that captures 16 acoustic images of a person for 4 frequencies and 4 positions, a study was carried out to improve the performance of the system. On a first stage, an analysis to determine which images provide more information to the system was carried out showing that a set of 12 images allows the system to obtain results that are equivalent to using all of the 16 images. Finally, optimization techniques were used to obtain the set of weights associated with each acoustic image that maximizes the performance of the biometric system. These results improve significantly the performance of the preliminary system, while reducing the time of acquisition and computational burden, since the number of acoustic images was reduced.

  20. Prediction of the effects of soil and target properties on the antipersonnel landmine detection performance of ground-penetrating radar: A Colombian case study

    Science.gov (United States)

    Lopera, Olga; Milisavljevic, Nada

    2007-09-01

    The performance of ground-penetrating (GPR) radar is determined fundamentally by the soil electromagnetic (EM) properties and the target characteristics. In this paper, we predict the effects of such properties on the antipersonnel (AP) landmine detection performance of GPR in a Colombian scenario. Firstly, we use available soil geophysical information in existing pedotransfer models to calculate soil EM properties. The latter are included in a two-dimensional (2D), finite-difference time-domain (FDTD) modeling program in conjunction with the characteristics of AP landmines to calculate the buried target reflection. The approach is applied to two soils selected among Colombian mine-affected areas, and several local improvised explosive devices (IEDs) and AP landmines are modeled as targets. The signatures from such targets buried in the selected soils are predicted, considering different conditions. Finally, we show how the GPR can contribute in detecting low- and non-metallic targets in these Colombian soils. Such a system could be quite adequate for complementing humanitarian landmine detection by metal detectors.

  1. Evolution of a highly dilatant fault zone in the grabens of Canyonlands National Park, Utah/USA – integrating field work, ground penetrating radar and airborne imagery analysis

    Directory of Open Access Journals (Sweden)

    M. Kettermann

    2015-03-01

    Full Text Available The grabens of the Canyonlands National Park are a young and active system of sub-parallel, arcuate grabens, whose evolution is the result of salt movement in the subsurface and a slight regional tilt of the faulted strata. We present results of ground penetrating radar surveys in combination with field observations and analysis of high resolution airborne imagery. GPR data show intense faulting of the Quaternary sediments at the flat graben floors, implying a more complex fault structure than visible at the surface. Direct measurements of heave and throw at several locations to infer fault dips at depth, combined with observations of primary joint surfaces in the upper 100 m suggest a model of the highly dilatant fault geometry in profile. Sinkholes observed in the field as well as in airborne imagery give insights in local massive dilatancy and show where water and sediments are transported underground. Based on correlations of paleosols observed in outcrops and GPR profiles, we argue that the grabens in Canyonlands National Park are either older than previously assumed, or that sedimentation rates were much higher in the Pleistocene.

  2. 探地雷达在地下管线探测中的应用%Application of Ground Penetrating Radar in Underground Pipeline Detecting

    Institute of Scientific and Technical Information of China (English)

    刘永义; 杨磊; 王瑞芳

    2015-01-01

    介绍了探地雷达的工作原理和数据采集系统,利用探地雷达进行地下管线的探测,探明了指定路线上的管线埋深情况,对结果进行精度分析比较,表明探地雷达探测出的管线点埋深符合限差要求,可以用于地下非金属管线的探测,对管线探测仪是一种补充。%The working principle and data acquisition system of ground penetrating radar are introduced in this paper .The detection of underground pipeline using GPR proves the buried depth in the designated route .The accuracy of analysis and comparison ,shows that the buried depth detected using GPR is in line with the requirements and can be used for the detection of underground non metal pipeline .At the same time ,it is a supplement to the nondestructive detection of pipeline detector cases only metal pipeline .

  3. Evolution of a highly dilatant fault zone in the grabens of Canyonlands National Park, Utah/USA - integrating field work, ground penetrating radar and airborne imagery analysis

    Science.gov (United States)

    Kettermann, M.; Grützner, C.; van Gent, H. W.; Urai, J. L.; Reicherter, K.; Mertens, J.

    2015-03-01

    The grabens of the Canyonlands National Park are a young and active system of sub-parallel, arcuate grabens, whose evolution is the result of salt movement in the subsurface and a slight regional tilt of the faulted strata. We present results of ground penetrating radar surveys in combination with field observations and analysis of high resolution airborne imagery. GPR data show intense faulting of the Quaternary sediments at the flat graben floors, implying a more complex fault structure than visible at the surface. Direct measurements of heave and throw at several locations to infer fault dips at depth, combined with observations of primary joint surfaces in the upper 100 m suggest a model of the highly dilatant fault geometry in profile. Sinkholes observed in the field as well as in airborne imagery give insights in local massive dilatancy and show where water and sediments are transported underground. Based on correlations of paleosols observed in outcrops and GPR profiles, we argue that the grabens in Canyonlands National Park are either older than previously assumed, or that sedimentation rates were much higher in the Pleistocene.

  4. Imaging of Archaeological Remains at Barcombe Roman Villa using Microwave Tomographic Depictions of Ground Penetrating Radar Data

    Science.gov (United States)

    Soldovieri, F.; Utsi, E.; Alani, A.; Persico, R.

    2012-04-01

    The site of the Barcombe Romano-British villa lies in a field on the perimeter of Barcombe village in East Sussex, England. The site came to the attention of the Mid Sussex Field Archaeological Team (MSFAT) and the University College London Field Archaeological Unit (UCL, subsequently replaced by the Centre for Continuing Education of the University of Sussex, CCE) because it was in danger of disappearing altogether without being adequately recorded [1]. In common with many other UK sites of the period, the villa had been extensively robbed out in the centuries following its demise in order to provide building material for the adjacent village and its associated farms, a common problem with Romano-British sites in the UK [2]. In addition, the site is positioned on the ridge of a field in agricultural use and has therefore been extensively ploughed out. As a result, the archaeological evidence was sparse and the little that remained was being rapidly eroded. In April 2001, a Ground Penetrating Radar (GPR) survey was carried out jointly by the Department of Engineering, Portsmouth and Utsi Electronics Ltd on behalf of the archaeological team in order to investigate the possibility of mapping both the villa and earlier prehistoric remains on the same ridge. Using a 40m by 60m grid laid out by the archaeological team, a Groundvue 1, with antennas of central frequency 400MHz, was used to survey along a series of parallel transects at intervals of 50cm. The sampling interval along the line of survey was 5cm and probing was carried out to 40ns. The results of the GPR survey, including a comparison with the evidence from the resistivity work, were published in 2002 [3]. The original GPR data were processed (using the ReflexW package) by applying background removal, adding time based gain, averaging over 2 traces in order to reduce noise resulting from the relative movement of the antennas across the ploughed field and finally applying a Bandpass Butterworth filter of 200

  5. Giant Magnetostrictive Material Loudspeaker System Acoustic Radiation Simulation

    Institute of Scientific and Technical Information of China (English)

    WANG Rui; ZHANG Yong-fa

    2008-01-01

    An infinite panel model of giant magnetostrictive material loudspeaker system (GMMLS) is proposed by making use of finite element method(FEM). Bending wave eigenfunction is introduced to describe the acoustic radiation condition of the panel. Far-field response in different conditions is calculated by changing the mass surface density. Conclusion is obtained by analyzing the curves simulated, that panel which has larger mass surface density can hardly generate far-field acoustic radiation for lower frequency, while the panel has smaller mass surface density generates far-field acoustic radiation for lower frequency evenly and stronger.

  6. Aeroelastic-Acoustics Simulation of Flight Systems

    Science.gov (United States)

    Gupta, kajal K.; Choi, S.; Ibrahim, A.

    2009-01-01

    This paper describes the details of a numerical finite element (FE) based analysis procedure and a resulting code for the simulation of the acoustics phenomenon arising from aeroelastic interactions. Both CFD and structural simulations are based on FE discretization employing unstructured grids. The sound pressure level (SPL) on structural surfaces is calculated from the root mean square (RMS) of the unsteady pressure and the acoustic wave frequencies are computed from a fast Fourier transform (FFT) of the unsteady pressure distribution as a function of time. The resulting tool proves to be unique as it is designed to analyze complex practical problems, involving large scale computations, in a routine fashion.

  7. Condensed research overview of agricultural drainage pipe detection and assessment using ground penetrating radar

    Science.gov (United States)

    Agricultural subsurface drainage practices are employed in many places throughout the world to remove excess water from soil, thereby improving crop production. In order to improve and evaluate the efficiency of these subsurface drainage systems, non-destructive methods are needed to not only locate...

  8. Devonian lacustrine shore zone architecture: giving perspective to cliff exposures with ground penetrating radar

    DEFF Research Database (Denmark)

    Andrews, Steven D.; Moreau, Julien; Archer, Stuart

    . However, this depositional environment ought to be relatively dynamic with sand body migration and erosions. In addition, along the coastal cliffs, the exposures are mainly on the same strike direction. To better understand the peculiar shore zone system, we carried out very high resolution sedimentary...

  9. Feature-Based Methods for Landmine Detection with Ground Penetrating Radar

    Science.gov (United States)

    2012-09-27

    variations and noisy inputs, perfect solutions are difficult to achieve, and no single source of informa- tion can provide a satisfactory solution...International Conference on Fuzzy Systems Sheraton Vancouver Wall Centre Hotel , Vancouver, BC, Canada July 16-21, 2006 1494 Fig. 1. a collection of few GPR...the interaction of the GPR with the surrounding components. Although differentiation is sensitive to noise, the NIITEK data are not very noisy ; thus

  10. High-resolution mapping, modeling, and evolution of subsurface geomorphology using ground-penetrating radar techniques

    Digital Repository Service at National Institute of Oceanography (India)

    Loveson, V.J.; Gujar, A.R.

    data over an area under study. The gap between sample locations are to be either simulated or manipulated through various statistical methods. Under such conditions, mapping of the area may not yield the reality of the subsurface features in between... continuous profiles along with 200 MHz antenna and measuring wheel. Some times for confirmation, 400 MHz antenna was also used. GPR system was initialized in the field so that the ground reality, related to geo-electrical conditions of the field...

  11. An Acoustic Echo Cancellation System based on Adaptive Algorithm

    OpenAIRE

    2012-01-01

    Adaptive filtering technique is one of the core technologies in digital signal processing and finds numerous application areas in science as well as in industry. Adaptive filtering technique is widely used in many applications, including echo cancellation, adaptive noise cancellation, adaptive beam forming and adaptive equalization. Acoustic echo is a common occurrence in today’s telecommunication systems. The distraction caused by the acoustic echo, reduces the speech quality in the communic...

  12. Localizing Ground Penetrating RADAR: A Step Towards Robust Autonomous Ground Vehicle Localization

    Science.gov (United States)

    2016-07-14

    error and transition period between 50 s and 60 s corresponds to the northern 7 m radius U-turn. Journal of Field Robotics DOI 10.1002/rob Cornick et...estimating time-related bias errors . Journal of Field Robotics DOI 10.1002/rob 96 • Journal of Field Robotics —2016 Figure 17. Cumulative distribution of...the LIDAR systems be- cause of their use of optics and their operation in dynamic environments. Journal of Field Robotics 33(1), 82–102 (2016) C

  13. Devonian lacustrine shore zone architecture: giving perspective to cliff exposures with ground penetrating radar

    DEFF Research Database (Denmark)

    Andrews, Steven D.; Moreau, Julien; Archer, Stuart

    of these units. The cycles are on average 16-m-thick and comprise deep lake, perennial lake and playa facies. The shore zone facies reaches 2 to 3.5 m in thickness and is found within the playa facies. On the exposures, the shore zone facies seems to be aggrading with most of the layers apparently subhorizontal...... occurred over a wide area as the lake margin migrated back and forth, and gradually transgressed. Continued transgression forced fluvial systems back towards the basin margin....

  14. Adaptive identification of acoustic multichannel systems using sparse representations

    CERN Document Server

    Helwani, Karim

    2014-01-01

    This book treats the topic of extending the adaptive filtering theory in the context of massive multichannel systems by taking into account a priori knowledge of the underlying system or signal. The starting point is exploiting the sparseness in acoustic multichannel system in order to solve the non-uniqueness problem with an efficient algorithm for adaptive filtering that does not require any modification of the loudspeaker signals.The book discusses in detail the?derivation of general sparse representations of acoustic MIMO systems?in signal or system dependent transform domains.?Efficient a

  15. Three-dimensional ground penetrating radar imaging using multi-frequency diffraction tomography

    Energy Technology Data Exchange (ETDEWEB)

    Mast, J.E.; Johansson, E.M. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    In this talk we present results from a three-dimensional image reconstruction algorithm for impulse radar operating in monostatic pule-echo mode. The application of interest to us is the nondestructive evaluation of civil structures such as bridge decks. We use a multi-frequency diffraction tomography imaging technique in which coherent backward propagations of the received reflected wavefield form a spatial image of the scattering interfaces within the region of interest. This imaging technique provides high-resolution range and azimuthal visualization of the subsurface region. We incorporate the ability to image in planarly layered conductive media and apply the algorithm to experimental data from an offset radar system in which the radar antenna is not directly coupled to the surface of the region. We present a rendering in three-dimensions of the resulting image data which provides high-detail visualization.

  16. Coal mine hazard detection using in-seam ground-penetrating-radar transillumination

    Energy Technology Data Exchange (ETDEWEB)

    Foss, M.M.; Leckenby, R.J.

    1987-01-01

    The Bureau of Mines recently completed preliminary studies to demonstrate the feasibility of using GPR for in-seam hazard detection. Investigations included air and coal tests for the purpose of checking equipment accuracy, coal penetration, and other factors such as the effects of receiver orientation. Further investigations involved using both a short pulse and a new prototype synthetic-pulse system to locate a clay vein in a coal seam using transillumination. Analysis of the tomographic images show the presence of the clay vein, although its boundaries are unclear due to the tomography method used. Results of these preliminary studies show that GPR is feasible for use in in-seam hazard detection and point the direction that future research should take.

  17. The effectiveness of ground-penetrating radar surveys in the location of unmarked burial sites in modern cemeteries

    Science.gov (United States)

    Fiedler, Sabine; Illich, Bernhard; Berger, Jochen; Graw, Matthias

    2009-07-01

    Ground-penetration radar (GPR) is a geophysical method that is commonly used in archaeological and forensic investigations, including the determination of the exact location of graves. Whilst the method is rapid and does not involve disturbance of the graves, the interpretation of GPR profiles is nevertheless difficult and often leads to incorrect results. Incorrect identifications could hinder criminal investigations and complicate burials in cemeteries that have no information on the location of previously existing graves. In order to increase the number of unmarked graves that are identified, the GPR results need to be verified by comparing them with the soil and vegetation properties of the sites examined. We used a modern cemetery to assess the results obtained with GPR which we then compared with previously obtained tachymetric data and with an excavation of the graves where doubt existed. Certain soil conditions tended to make the application of GPR difficult on occasions, but a rough estimation of the location of the graves was always possible. The two different methods, GPR survey and tachymetry, both proved suitable for correctly determining the exact location of the majority of graves. The present study thus shows that GPR is a reliable method for determining the exact location of unmarked graves in modern cemeteries. However, the method did not allow statements to be made on the stage of decay of the bodies. Such information would assist in deciding what should be done with graves where ineffective degradation creates a problem for reusing graves following the standard resting time of 25 years.

  18. Nonparametric Bayesian time-series modeling and clustering of time-domain ground penetrating radar landmine responses

    Science.gov (United States)

    Morton, Kenneth D., Jr.; Torrione, Peter A.; Collins, Leslie

    2010-04-01

    Time domain ground penetrating radar (GPR) has been shown to be a powerful sensing phenomenology for detecting buried objects such as landmines. Landmine detection with GPR data typically utilizes a feature-based pattern classification algorithm to discriminate buried landmines from other sub-surface objects. In high-fidelity GPR, the time-frequency characteristics of a landmine response should be indicative of the physical construction and material composition of the landmine and could therefore be useful for discrimination from other non-threatening sub-surface objects. In this research we propose modeling landmine time-domain responses with a nonparametric Bayesian time-series model and we perform clustering of these time-series models with a hierarchical nonparametric Bayesian model. Each time-series is modeled as a hidden Markov model (HMM) with autoregressive (AR) state densities. The proposed nonparametric Bayesian prior allows for automated learning of the number of states in the HMM as well as the AR order within each state density. This creates a flexible time-series model with complexity determined by the data. Furthermore, a hierarchical non-parametric Bayesian prior is used to group landmine responses with similar HMM model parameters, thus learning the number of distinct landmine response models within a data set. Model inference is accomplished using a fast variational mean field approximation that can be implemented for on-line learning.

  19. Geological disaster survey based on Curvelet transform with borehole Ground Penetrating Radar in Tonglushan old mine site.

    Science.gov (United States)

    Tang, Xinjian; Sun, Tao; Tang, Zhijie; Zhou, Zenghui; Wei, Baoming

    2011-06-01

    Tonglushan old mine site located in Huangshi City, China, is very famous in the world. However, some of the ruins had suffered from geological disasters such as local deformation, surface cracking, in recent years. Structural abnormalities of rock-mass in deep underground were surveyed with borehole ground penetrating radar (GPR) to find out whether there were any mined galleries or mined-out areas below the ruins. With both the multiresolution analysis and sub-band directional of Curvelet transform, the feature information of targets' GPR signals were studied on Curvelet transform domain. Heterogeneity of geotechnical media and clutter jamming of complicated background of GPR signals could be conquered well, and the singularity characteristic information of typical rock mass signals could be extracted. Random noise had be removed by thresholding combined with Curvelet and the statistical characteristics of wanted signals and the noise, then direct wave suppression and the spatial distribution feature extraction could obtain a better result by making use of Curvelet transform directional. GprMax numerical modeling and analyzing of the sample data have verified the feasibility and effectiveness of our method. It is important and applicable for the analyzing of the geological structure and the disaster development about the Tonglushan old mine site.

  20. Preliminary results of sequential monitoring of simulated clandestine graves in Colombia, South America, using ground penetrating radar and botany.

    Science.gov (United States)

    Molina, Carlos Martin; Pringle, Jamie K; Saumett, Miguel; Hernández, Orlando

    2015-03-01

    In most Latin American countries there are significant numbers of missing people and forced disappearances, 68,000 alone currently in Colombia. Successful detection of shallow buried human remains by forensic search teams is difficult in varying terrain and climates. This research has created three simulated clandestine burial styles at two different depths commonly encountered in Latin America to gain knowledge of optimum forensic geophysics detection techniques. Repeated monitoring of the graves post-burial was undertaken by ground penetrating radar. Radar survey 2D profile results show reasonable detection of ½ clothed pig cadavers up to 19 weeks of burial, with decreasing confidence after this time. Simulated burials using skeletonized human remains were not able to be imaged after 19 weeks of burial, with beheaded and burnt human remains not being able to be detected throughout the survey period. Horizontal radar time slices showed good early results up to 19 weeks of burial as more area was covered and bi-directional surveys were collected, but these decreased in amplitude over time. Deeper burials were all harder to image than shallower ones. Analysis of excavated soil found soil moisture content almost double compared to those reported from temperate climate studies. Vegetation variations over the simulated graves were also noted which would provide promising indicators for grave detection.

  1. The utility of ground-penetrating radar and its time-dependence in the discovery of clandestine burials.

    Science.gov (United States)

    Salsarola, Dominic; Poppa, Pasquale; Amadasi, Alberto; Mazzarelli, Debora; Gibelli, Daniele; Zanotti, Emma; Porta, Davide; Cattaneo, Cristina

    2015-08-01

    In the field of forensic investigation burial is a relatively common method of hiding a corpse. The location of clandestine graves is, however, a particularly difficult task in which multiple forensic disciplines such as anthropology, botany or archaeology can provide valuable assistance. The use of GPR (ground-penetrating radar) has recently been introduced as a method in the detection of these graves, but what is the true potential of this tool in an operative search scenario? In this study a total of 11 pig carcasses were buried in two wooded areas, each presenting a similar soil composition. The animals were subsequently exhumed at regular intervals, ranging from 2 to 111 weeks, using systematic GPR analysis of the burial sites and archaeological recovery of the subjects that were then autopsied. GPR proved to be useful in recognizing anomalies at the chosen depths of burial and appeared to be dependent on the state of decay of the samples, producing only slight anomalous readings in the presence of skeletal remains: at 92 weeks from burial the difference in signal was weak and at 111 weeks GPR survey offered no helpful information as to burial location. The experiment, in this particular context, determined the technique as being successful in the presence of recent burials, highlighting the need for a multidisciplinary approach in the operative search for buried human remains.

  2. Estimating Carbon Stocks Along Depressional Wetlands Using Ground Penetrating Radar (GPR) in the Disney Wilderness Preserve (Orlando, Florida)

    Science.gov (United States)

    McClellan, M. D.; Comas, X.; Wright, W. J.; Mount, G. J.

    2014-12-01

    Peat soils store a large fraction of the global carbon (C) in soil. It is estimated that 95% of carbon in peatlands is stored in the peat soil, while less than 5% occurs in the vegetation. The majority of studies related to C stocks in peatlands have taken place in northern latitudes leaving the tropical and subtropical latitudes clearly understudied. In this study we use a combination of indirect non-invasive geophysical methods (mainly ground penetrating radar, GPR) as well as direct measurements (direct coring) to calculate total C stocks within subtropical depressional wetlands in the Disney Wilderness Preserve (DWP, Orlando, FL). A set of three-dimensional (3D) GPR surveys were used to detect variability of the peat layer thickness and the underlying peat-sand mix layer across several depressional wetlands. Direct samples collected at selected locations were used to confirm depth of each interface and to estimate C content in the laboratory. Layer thickness estimated from GPR and direct C content were used to estimate total peat volume and C content for the entire depressional wetland. Through the use of aerial photos a relationship between surface area along the depressional wetlands and total peat thickness (and thus C content) was established for the depressions surveyed and applied throughout the entire preserve. This work shows the importance of depressional wetlands as critical contributors of the C budget at the DWP.

  3. Alpine ice cores and ground penetrating radar: combined investigations for glaciological and climatic interpretations of a cold Alpine ice body

    Energy Technology Data Exchange (ETDEWEB)

    Eisen, Olaf; Nixdorf, Uwe [Alfred-Wegener-Inst. fuer Polar- und Meeresforschung, Bremerhaven (Germany); Keck, Lothar; Wagenbach, Dietmar [Univ. Heidelberg (Germany). Inst. fuer Umweltphysik

    2003-11-01

    Accurate interpretation of ice cores as climate archives requires detailed knowledge of their past and present geophysical environment. Different techniques facilitate the determination and reconstruction of glaciological settings surrounding the drilling location. During the ALPCLIM1 project, two ice cores containing long-term climate information were retrieved from Colle Gnifetti, Swiss-Italian Alps. Here, we investigate the potential of ground penetrating radar (GPR) surveys, in conjunction with ice core data, to obtain information about the internal structure of the cold Alpine ice body to improve climatic interpretations. Three drill sites are connected by GPR profiles, running parallel and perpendicular to the flow line, thus yielding a three-dimensional picture of the subsurface and enabling the tracking of internal reflection horizons between the locations. As the observed reflections are of isochronic origin, they permit the transfer of age-depth relations between the ice cores. The accuracy of the GPR results is estimated by comparison of transferred timescales with original core datings, independent information from an older ice core, and, based on glaciological surface data, findings from flow modeling. Our study demonstrates that GPR is a mandatory tool for Alpine ice core studies, as it permits mapping of major transitions in physical-chemical properties, transfer of age-depth relations between sites, correlate signals in core records for interpretation, and establish a detailed picture of the flow regime surrounding the climate archive.

  4. A Study of Concrete Hydration and Dielectric Relaxation Mechanism Using Ground Penetrating Radar and Short-Time Fourier Transform

    Directory of Open Access Journals (Sweden)

    Lai WL

    2010-01-01

    Full Text Available Abstract Ground penetrating radar (GPR was used to characterize the frequency-dependent dielectric relaxation phenomena in ordinary Portland cement (OPC hydration in concrete changing from fresh to hardened state. The study was experimented by measuring the changes of GPR A-scan waveforms over a period of 90 days, and processed the waveforms with short-time Fourier transform (STFT in joint time-frequency analysis (JTFA domain rather than a conventional time or frequency domain alone. The signals of the direct wave traveled at the concrete surface and the reflected wave from an embedded steel bar were transformed with STFT, in which the changes of peak frequency over ages were tracked. The peak frequencies were found to increase with ages and the patterns were found to match closely with primarily the well-known OPC hydration process and secondarily, the evaporation effect. The close match is contributed to the simultaneous effects converting free to bound water over time, on both conventional OPC hydration and dielectric relaxation mechanisms.

  5. Regional characteristics of sea ice thickness in Canadian shelf and Arctic Archipelago measured by Ground Penetrating Radar

    Institute of Scientific and Technical Information of China (English)

    LI Tao; ZHAO Jinping; JIAO Yutian; HOU Jiaqiang; MU Longjiang

    2015-01-01

    Ground Penetrating Radar (GPR) measurements of sea ice thickness including undeformed ice and ridged ice were carried out in the central north Canadian Archipelago in spring 2010. Results have shown a significant spatial heterogeneity of sea ice thickness across the shelf. The undeformed multi-year fast ice of (2.05±0.09) m thick was investigated southern inshore zone of Borden island located at middle of the observational section, which was the observed maximum thickness in the field work. The less thick sea ice was sampled across a flaw lead with the thicknesses of (1.05±0.11) m for the pack ice and (1.24±0.13) m for the fast ice. At the northernmost spot of the section, the undeformed multi-year pack ice was (1.54±0.22) m thick with a ridged ice of 2.5 to 3 m, comparing to the multi-year fast ice with the thickness of (1.67±0.16) m at the southernmost station in the Prince Gustaf Adolf Sea.

  6. Parameterizing road construction in route-based road weather models: can ground-penetrating radar provide any answers?

    Science.gov (United States)

    Hammond, D. S.; Chapman, L.; Thornes, J. E.

    2011-05-01

    A ground-penetrating radar (GPR) survey of a 32 km mixed urban and rural study route is undertaken to assess the usefulness of GPR as a tool for parameterizing road construction in a route-based road weather forecast model. It is shown that GPR can easily identify even the smallest of bridges along the route, which previous thermal mapping surveys have identified as thermal singularities with implications for winter road maintenance. Using individual GPR traces measured at each forecast point along the route, an inflexion point detection algorithm attempts to identify the depth of the uppermost subsurface layers at each forecast point for use in a road weather model instead of existing ordinal road-type classifications. This approach has the potential to allow high resolution modelling of road construction and bridge decks on a scale previously not possible within a road weather model, but initial results reveal that significant future research will be required to unlock the full potential that this technology can bring to the road weather industry.

  7. Investigating fluvial features with electrical resistivity imaging and ground-penetrating radar: The Guadalquivir River terrace (Jaen, Southern Spain)

    Science.gov (United States)

    Rey, J.; Martínez, J.; Hidalgo, M. C.

    2013-09-01

    A geophysical survey has been conducted on the lowest terrace levels and the present day floodplain of the current course of the Guadalquivir River, passing through the province of Jaen (Spain), using two techniques: electrical resistivity imaging (ERI) and ground-penetrating radar (GPR). Three areas have been selected. In one of these sectors (Los Barrios) there is an old quarry where there are excellent outcrops that allow for the calibration of the survey techniques. Facies associations on these outcrops are typical of meandering rivers with sequences of channel fills, lateral accretion of point-bars and floodplain facies. The usefulness of the two methods is analysed and compared as a support for stratigraphic and sedimentological studies. The geometry and lithofacies of subsurface deposits were characterised using ERI and compared with field observations. A total of 5 electrical resistivity imaging profiles were obtained. The changes in electric resistivity highlight granulometric differences in terrace sediments. This technique can thus be used to identify the morphology of these bodies, the lithofacies (silt, sand or gravel) and buried channel pattern. In addition, 16 GPR profiles using 100 and 250 MHz antennas were acquired, indicating terrace morphology and the filling of the sedimentary bodies in a more detailed manner than in ERI. The study thus allows for inferring the existence of channel migration, the lateral accretion of point bars and the presence of vertical accretion deposits attributable to the floodplains.

  8. Archaeological sites at Rio de Janeiro State, Brazil, with their contents enhanced by the use of ground penetrating radar

    Science.gov (United States)

    Ferrucio da Rocha, Paul L.; da Silva Cezar, Glroia; Buarque, Angela; da Costa, Ariovaldo

    2000-04-01

    This presentation refers to the application of the Ground Penetrating Radar on two archaeological sites: Serrano and Morro Grande, situated at Araruama County, Rio de Janeiro, Brazil, with the purpose of contributing to the knowledge concerning a prehistoric indigenous culture, associated with the 'Tupinamba' that inhabited the region at prehistoric times. This research is being realized with the partnership of the Anthropology Department of the National Museum and the Geology Department, both departments pertaining to the Rio de Janeiro Federal University. The archaeological remains of the study area are mainly characterized by pottery appliance for several uses, including funeral urns, which were buried within layers of sand and clay. Several profiles were made, using a RAMAC device, with a 200 MHz frequency antenna, surrounding some partially exposed potters, in the sand quarry, at the Serrano site. The resultant radargrams conceived a response model for the archaeological and soil characteristics of the area. These radargrams are being used as correlative models for the interpretation of profiles performed at the Morro Grande site, which presents similar characteristics of the Serrano site. The generated models are intended to guide the future excavations in the archeological sites of Ri de Janeiro.

  9. 4D ground penetrating radar measurements as non-invasive means for hydrological process investigation

    Science.gov (United States)

    Jackisch, Conrad; Allroggen, Niklas

    2017-04-01

    The missing vision into the subsurface appears to be a major limiting factor for our hydrological process understanding and theory development. Today, hydrology-related sciences have collected tremendous evidence for soils acting as drainage network and retention stores simultaneously in structured and self-organising domains. However, our present observation technology relies mainly on point-scale sensors, which integrate over a volume of unknown structures and is blind for their distribution. Although heterogeneity is acknowledged at all scales, it is rarely seen as inherent system property. At small scales (soil moisture probe) and at large scales (neutron probe) our measurements leave quite some ambiguity. Consequently, spatially and temporally continuous measurement of soil water states is essential for advancing our understanding and development of subsurface process theories. We present results from several irrigation experiments accompanied by 2D and 3D time-lapse GPR for the development of a novel technique to visualise and quantify water dynamics in the subsurface. Through the comparison of TDR, tracer and gravimetric measurement of soil moisture it becomes apparent that all sensor-based techniques are capable to record temporal dynamics, but are challenged to precisely quantify the measurements and to extrapolate them in space. At the same time excavative methods are very limited in temporal and spatial resolution. The application of non-invasive 4D GPR measurements complements the existing techniques and reveals structural and temporal dynamics simultaneously. By consequently increasing the density of the GPR data recordings in time and space, we find means to process the data also in the time-dimension. This opens ways to quantitatively analyse soil water dynamics in complex settings.

  10. High resolution imaging of vadose zone transport using surface and crosswell ground penetrating radar methods

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Kenneth H.; Kowalsky, Mike B.; Peterson, John E.

    2002-11-05

    -groundwater system control flow geometry? (2) What physical properties or mechanisms control flow and transport in unconsolidated soils of the vadose zone? (3) What is the optimum suite of field tests to provide information for predicting flow and transport behavior? (4) How can the information obtained during site characterization be used for building confidence in predictive numerical models? Fully developed, application of geophysics should enable location of contaminant distributions. Questions addressed in this study were the sensitivity, resolution, and accuracy of the geophysical methods in order to derive the spatial and temporal distribution of properties controlling transport and contaminant distribution between and away from boreholes and the surface. Implicit in this activity is that geophysical methods will be used to extrapolate and extend measurements made at the point scale to the volumetric scale. Overall there are two broad hypotheses being addressed in the geophysical work: (1) Geophysical methods can identify physical and chemical heterogeneity controlling contaminant transport at a meaningful scale. (2) Geophysical methods have the sensitivity to directly or indirectly detect the location of introduced fluids and/or contaminants at relevant concentrations (i.e. the subsurface has been altered from its natural state enough to create anomalies that can be detected in terms of a combination of mechanical, electrical, and thermal effects).

  11. Mapping exposed and buried lava flows using synthetic aperture and ground-penetrating radar in Craters of the Moon lava field

    Science.gov (United States)

    Khan, Shuhab D.; Heggy, Essam; Fernandez, Jaime

    2007-11-01

    The Craters of the Moon (COM) lava field has a multiple eruptive history. Burial of older flows has resulted in complex subsurface stratigraphy. For the older eruptive periods, the locations of source vents and the extension of lava flows are either speculative or unknown, because they are buried under more recent pyroclastics. In this study, we used surface and subsurface backscatter characteristics of the P- and L-band polarimetric airborne synthetic aperture radar (AIRSAR) data and ground-penetrating radar (GPR) soundings to resolve different exposed and buried lava flows. Our primary objective is to define the most effective polarization and frequency for mapping, resolving, and characterizing different lava types in the volcanic field. Polarimetric analysis of AIRSAR images from COM allows a clear recognition of the aa and pahoehoe lava types as a result of the variability in their roughness. Our results suggest that the HV cross-polarized, AIRSAR L-band is capable of producing a detailed map delineating surface lava with different surface backscattering properties. An accuracy assessment utilizing the geological map of the Inferno Cone area was performed to quantify the reliability of differentiating lava types and mapping the lava flows extension below loose pyroclastics using AIRSAR data. Results shows an ability of P-band SAR to map buried structures up to 3 meters deep under loose cinder and ash deposits, resolving buried fissures, outcrops, and lava flows that were validated with ground-truth GPR surveys. The techniques used in this study provide a tool to assess volcanic hazards in remote and inaccessible places. Also it could be an aid in the study of other planets and planetary bodies in the solar system.

  12. The Application of Ground-Penetrating Radar to Transportation Engineering: Recent Advances and New Perspectives (GI Division Outstanding ECS Award Lecture)

    Science.gov (United States)

    Tosti, Fabio; Benedetto, Andrea; Pajewski, Lara; Alani, Amir M.

    2017-04-01

    Ground-penetrating radar (GPR) is one of the most acknowledged and established non-destructive testing (NDT) techniques within the context of the health monitoring and assessment of transportation infrastructures. GPR is being increasingly used for the effective management of infrastructural assets as it weakens the case for using other destructive monitoring methods, such as digging holes, and allows for rapid and reliable detection of many causes of the subsurface damage. Thereby, its usage favours the optimisation of the economical expenditure for the effective maintenance of great infrastructures as well as it improves the public safety by preventing or not raising the risk of accidents. GPR has been used in highway, railway and airfield engineering as well as for the monitoring of critical infrastructures, such as bridges and tunnels. It has found established use in the assessment of the geometric properties of the subsurface, such as in the case of the evaluation of the pavement layer thicknesses, or the size of the rebars in concrete-made structural components. Major physical-based investigations have been focused on the evaluation of the moisture ingress in flexible road pavements and in concrete structures, as well as on the detection of the rebars corrosion caused by the ingress of chloride. The majority of these parameters are evaluated using methods of signal analysis and data processing based on the signal in the time domain. The sophistication of the hardware and software of the GPR systems over the last few years as well as the recent advances achieved in the research have contributed to raise the high potential of this non-destructive technique and paved the way towards new application areas in transportation engineering. In particular, GPR is nowadays finding major application when used with complementary non-destructive testing techniques, although it has still proved to provide reliable results in various self-standing applications. This work

  13. Individually Identifiable Surface Acoustic Wave Sensors, Tags and Systems

    Science.gov (United States)

    Hines, Jacqueline H. (Inventor); Solie, Leland P. (Inventor); Tucker, Dana Y. G. (Inventor); Hines, Andrew T. (Inventor)

    2017-01-01

    A surface-launched acoustic wave sensor tag system for remotely sensing and/or providing identification information using sets of surface acoustic wave (SAW) sensor tag devices is characterized by acoustic wave device embodiments that include coding and other diversity techniques to produce groups of sensors that interact minimally, reducing or alleviating code collision problems typical of prior art coded SAW sensors and tags, and specific device embodiments of said coded SAW sensor tags and systems. These sensor/tag devices operate in a system which consists of one or more uniquely identifiable sensor/tag devices and a wireless interrogator. The sensor device incorporates an antenna for receiving incident RF energy and re-radiating the tag identification information and the sensor measured parameter(s). Since there is no power source in or connected to the sensor, it is a passive sensor. The device is wirelessly interrogated by the interrogator.

  14. Exchanging knowledge and working together in COST Action TU1208: Short-Term Scientific Missions on Ground Penetrating Radar

    Science.gov (United States)

    Santos Assuncao, Sonia; De Smedt, Philippe; Giannakis, Iraklis; Matera, Loredana; Pinel, Nicolas; Dimitriadis, Klisthenis; Giannopoulos, Antonios; Sala, Jacopo; Lambot, Sébastien; Trinks, Immo; Marciniak, Marian; Pajewski, Lara

    2015-04-01

    This work aims at presenting the scientific results stemming from six Short-Term Scientific Missions (STSMs) funded by the COST (European COoperation in Science and Technology) Action TU1208 'Civil Engineering Applications of Ground Penetrating Radar' (Action Chair: Lara Pajewski, STSM Manager: Marian Marciniak). STSMs are important means to develop linkages and scientific collaborations between participating institutions involved in a COST Action. Scientists have the possibility to go to an institution abroad, in order to undertake joint research and share techniques/equipment/infrastructures that may not be available in their own institution. STSMs are particularly intended for Early Stage Researchers (ESRs), i.e., young scientists who obtained their PhD since no more than 8 years when they started to be involved in the Action. Duration of a standard STSM can be from 5 to 90 days and the research activities carried out during this short stay shall specifically contribute to the achievement of the scientific objectives of the supporting COST Action. The first STSM was carried out by Lara Pajewski, visiting Antonis Giannopoulos at The University of Edinburgh (United Kingdom). The research activities focused on the electromagnetic modelling of Ground Penetrating Radar (GPR) responses to complex targets. A set of test scenarios was defined, to be used by research groups participating to Working Group 3 of COST Action TU1208, to test and compare different electromagnetic forward- and inverse-scattering methods; these scenarios were modelled by using the well-known finite-difference time-domain simulator GprMax. New Matlab procedures for the processing and visualization of GprMax output data were developed. During the second STSM, Iraklis Giannakis visited Lara Pajewski at Roma Tre University (Italy). The study was concerned with the numerical modelling of horn antennas for GPR. An air-coupled horn antenna was implemented in GprMax and tested in a realistically

  15. Acoustic imaging for diagnostics of chemically reacting systems

    Science.gov (United States)

    Ramohalli, K.; Seshan, P.

    1983-01-01

    The concept of local diagnostics, in chemically reacting systems, with acoustic imaging is developed. The elements of acoustic imaging through ellipsoidal mirrors are theoretically discussed. In a general plan of the experimental program, the first system is chosen in these studies to be a simple open jet, non premixed turbulent flame. Methane is the fuel and enriched air is the oxidizer. This simple chemically reacting flow system is established at a Reynolds number (based on cold viscosity) of 50,000. A 1.5 m diameter high resolution acoustic mirror with an f-number of 0.75 is used to map the acoustic source zone along the axis of the flame. The results are presented as acoustic power spectra at various distances from the nozzle exit. It is seen that most of the reaction intensity is localized in a zone within 8 diameters from the exit. The bulk reactions (possibly around the periphery of the larger eddies) are evenly distributed along the length of the flame. Possibilities are seen for locally diagnosing single zones in a multiple cluster of reaction zones that occur frequently in practice. A brief outline is given of the future of this work which will be to apply this technique to chemically reacting flows not limited to combustion.

  16. Ground-penetrating radar study of beach-ridge deposits in Huangqihai Lake, North China: the imprint of washover processes

    Institute of Scientific and Technical Information of China (English)

    Xin SHAN; Xinghe YU; Peter D.CLIFT; Chengpeng TAN; Shunli LI; Zhixing WANG; Dongxu SU

    2016-01-01

    Determining the origin of beach ridges in lacustrine basins can often be problematic.The sedimentary processes responsible for formation of beach ridges on the north shore of Huangqihai Lake were investigated by using ground penetrating radar (GPR).A 400 MHz GPR antenna was used to achieve a high vertical resolution of 0.04-0.08 m.The radar stratigraphy was then determined using principles of seismic stratigraphy.The radar facies (RF) were determined by analyzing internal configuration and continuity of reflections,as well as reflection termination patterns.The identified RF fall into three groups (inclined,horizontal and irregular).The inclined group consists of RF that display inclined reflections.The horizontal group consists of RF that exhibit predominantly horizontal reflections.In the irregular group,the reflections are typically weak.RF with reflections with gently landward dips in the shore-normal profile are interpreted as washover sheet deposits.RF with steeply landward-dipping and imbricated reflections are interpreted as washover lobes.Washover sheets develop when overwash fails to enter a significant body of water and sedimentation takes place entirely on the relatively flattened topography.Washover lobe development occurs when overwash enters a region in which topography dips steeply landward,and sedimentation takes place on the surface of washover sheets or previous washover lobes.The beach-ridge deposits are interpreted as being formed entirely from vertically and laterally stacked washover sheets and washover lobes.They were formed by wave-dominated processes and secondary overwash processes supplemented by longshore currents.

  17. Ground-penetrating radar exploration for ancient monuments at the Valley of Mummies -Kilo 6, Bahariya Oasis, Egypt

    Science.gov (United States)

    Shaaban, Fathy A.; Abbas, Abbas M.; Atya, Magdy A.; Hafez, Mahfouz A.

    2009-06-01

    A Valley of Mummies was discovered recently by an Egyptian team at Bahariya Oasis, located about 380 km west of the pyramids. Four tombs were excavated, and inside them were found one hundred and five mummies (105), many of them beautifully gilded. These mummies, many sumptuously decorated with religious scenes, are the very best Roman-Period mummies ever found in Egypt. These remains are around 2000 years old, but they are in remarkable condition. A Ground-Penetrating Radar (GPR) had proved successful in detecting the cavities in resistive soil in which the mummies were found. The GPR survey conducted near the earlier-discovered tombs at Kilo-6 El-Bahariya to Farafra Oasis road is the focus of this paper. The GPR survey was conducted using the SIR-2000 attached to a 200 MHz monostatic antenna. The two areas to be surveyed were selected by the archaeologists in situ. Area one was 40 m × 40 m and Area two was 30 m × 15 m. A grid pattern survey in one direction; with one-meter profile spacing was done to both areas. In addition, a focusing survey was undertaken over the entire Area one. In addition, twenty long GPR profiles were conducted in an attempt to determine the outer, expected limits of the burial area. After the data acquisition, Reflex software was used for data processing and presentation. The final results of the radar survey: in the form of 2D radar records, time slices and 3D block diagrams; were used to guide the archaeologists during the excavation process. The excavation processes have been completed by the archaeologists, and many tombs and mummies were discovered. It is worthy to mention that, the excavations and location of tombs and cavities matched strongly with the GPR results.

  18. Investigating the Spatial and Temporal Variability of Water Saturation Within the Greenland Firn Aquifer Using Ground Penetrating Radar

    Science.gov (United States)

    Brautigam, N.

    2015-12-01

    Ground Penetrating Radar (GPR) is used to investigate the spatial and temporal saturation of the Greenland firn aquifer, using a method recently developed on a Svalbard icesheet (Christianson et. al., 2015). Currently, saturation of the firn is assumed to be 100% (Koenig et. al., 2014; Forster et. al., 2014), and using a firn density correction this saturation level drives the present liquid water volume estimate (140±20 Gt) of the Greenland firn aquifer (Koenig et. al., 2014). Based on earlier studies on mountain glacier firn aquifers, we suspect that saturation levels vary with depth, annual precipitation patterns, and local topography (Fountain, 1989; Christianson et. al., 2015). Refining the liquid water volume estimation is an important parameter as it allows for a better determination of the amount of water potentially available for release and consequent sea level rise, as well as to better model glacial processes such as englacial flow, crevasse fracture, and basal lubrication. GPR and GPS data collected along a 2.6 km transect in 2011, 2013, and 2014 in southeastern Greenland is used to measure the spatial and temporal variability of saturation levels within the aquifer. A bright reflector seen in the GPR at the water table depth responds to local topography. At surface lows, the reflector rises, intersecting annual density change layers visible in the GPR data. At these intersections, the annual layers deflect down beneath the water table before being lost due to signal attenuation. We assume that this deflection is due to a change in dielectric permittivity, and that by measuring the angle of deflection, and implementing a mixing model and density correction from nearby firn cores, we can determine the saturation level at each point along a deflection. This allows us to investigate the spatial and temporal variability of saturation within the firn aquifer.

  19. Investigating Hydrogeologic Controls on Sandhill Wetlands in Covered Karst with 2D Resistivity and Ground Penetrating Radar

    Science.gov (United States)

    Downs, C. M.; Nowicki, R. S.; Rains, M. C.; Kruse, S.

    2015-12-01

    In west-central Florida, wetland and lake distribution is strongly controlled by karst landforms. Sandhill wetlands and lakes are sand-filled upland basins whose water levels are groundwater driven. Lake dimensions only reach wetland edges during extreme precipitation events. Current wetland classification schemes are inappropriate for identifying sandhill wetlands due to their unique hydrologic regime and ecologic expression. As a result, it is difficult to determine whether or not a wetland is impacted by groundwater pumping, development, and climate change. A better understanding of subsurface structures and how they control the hydrologic regime is necessary for development of an identification and monitoring protocol. Long-term studies record vegetation diversity and distribution, shallow ground water levels and surface water levels. The overall goals are to determine the hydrologic controls (groundwater, seepage, surface water inputs). Most recently a series of geophysical surveys was conducted at select sites in Hernando and Pasco County, Florida. Electrical resistivity and ground penetrating radar were employed to image sand-filled basins and the top of the limestone bedrock and stratigraphy of wetland slopes, respectively. The deepest extent of these sand-filled basins is generally reflected in topography as shallow depressions. Resistivity along inundated wetlands suggests the pools are surface expressions of the surficial aquifer. However, possible breaches in confining clay layers beneath topographic highs between depressions are seen in resistivity profiles as conductive anomalies and in GPR as interruptions in otherwise continuous horizons. These data occur at sites where unconfined and confined water levels are in agreement, suggesting communication between shallow and deep groundwater. Wetland plants are observed outside the historic wetland boundary at many sites, GPR profiles show near-surface layers dipping towards the wetlands at a shallower

  20. Developing an Ice Volume Estimate of Jarvis Glacier, Alaska, using Ground-Penetrating Radar and High Resolution Satellite Imagery

    Science.gov (United States)

    Wu, N. L.; Campbell, S. W.; Douglas, T. A.; Osterberg, E. C.

    2013-12-01

    Jarvis Glacier is an important water source for Fort Greely and Delta Junction, Alaska. Yet with warming summer temperatures caused by climate change, the glacier is melting rapidly. Growing concern of a dwindling water supply has caused significant research efforts towards determining future water resources from spring melt and glacier runoff which feeds the community on a yearly basis. The main objective of this project was to determine the total volume of the Jarvis Glacier. In April 2012, a centerline profile of the Jarvis Glacier and 15 km of 100 MHz ground-penetrating radar (GPR) profiles were collected in cross sections to provide ice depth measurements. These depth measurements were combined with an interpreted glacier boundary (depth = 0 m) from recently collected high resolution WorldView satellite imagery to estimate total ice volume. Ice volume was calculated at 0.62 km3 over a surface area of 8.82 km2. However, it is likely that more glacier-ice exists within Jarvis Glacier watershed considering the value calculated with GPR profiles accounts for only the glacier ice within the valley and not for the valley side wall ice. The GLIMS glacier area database suggests that the valley accounts for approximately 50% of the total ice covered watershed. Hence, we are currently working to improve total ice volume estimates which incorporate the surrounding valley walls. Results from this project will be used in conjunction with climate change estimates and hydrological properties downstream of the glacier to estimate future water resources available to Fort Greely and Delta Junction.

  1. Long-term sequential monitoring of controlled graves representing common burial scenarios with ground penetrating radar: Years 2 and 3

    Science.gov (United States)

    Schultz, John J.; Walter, Brittany S.; Healy, Carrie

    2016-09-01

    Geophysical techniques such as ground-penetrating radar (GPR) have been successfully used for forensic searches to locate clandestine graves and physical evidence. However, additional controlled research is needed to fully understand the applicability of this technology when searching for clandestine graves in various environments, soil types, and for longer periods of time post-burial. The purpose of this study was to determine the applicability of GPR for detecting controlled graves in a Spodosol representing multiple burial scenarios for Years 2 and 3 of a three-year monitoring period. Objectives included determining how different burial scenarios are factors in producing a distinctive anomalous response; determining how different GPR imagery options (2D reflection profiles and horizontal time slices) can provide increased visibility of the burials; and comparing GPR imagery between 500 MHz and 250 MHz dominant frequency antennae. The research site contained a grid with eight graves representing common forensic burial scenarios in a Spodosol, a common soil type of Florida, with six graves containing a pig carcass (Sus scrofa). Burial scenarios with grave items (a deep grave with a layer of rocks over the carcass and a carcass wrapped in a tarpaulin) produced a more distinctive response with clearer target reflections over the duration of the monitoring period compared to naked carcasses. Months with increased precipitation were also found to produce clearer target reflections than drier months, particularly during Year 3 when many grave scenarios that were not previously visible became visible after increased seasonal rainfall. Overall, the 250 MHz dominant frequency antenna imagery was more favorable than the 500 MHz. While detection of a simulated grave may be difficult to detect over time, long term detection of a grave in a Spodosol may be possible if the disturbed spodic horizon is detected. Furthermore, while grave visibility increased with the 2D

  2. Estimating belowground carbon stocks in peatlands of the Ecuadorian páramo using ground-penetrating radar (GPR)

    Science.gov (United States)

    Comas, Xavier; Terry, Neil; Hribljan, John A.; Lilleskov, Erik A.; Suarez, Esteban; Chimner, Rodney A.; Kolka, Randy K.

    2017-02-01

    The páramo ecoregion of Ecuador contains extensive peatlands that are known to contain carbon (C) dense soils capable of long-term C storage. Although high-altitude mountain peatlands are typically small when compared to low-altitude peatlands, they are abundant across the Andean landscape and are likely a key component in regional C cycling. Since efforts to quantify peatland distribution and C stocks across the tropical Andes have been limited due to the difficulty in sampling remote areas with very deep peat, there is a large knowledge gap in our quantification of the current C pools in the Andean mountains, which limits our ability to predict and monitor change from high rates of land use and climate change. In this paper we tested if ground-penetrating radar (GPR), combined with manual coring and C analysis, could be used for estimating C stocks in peatlands of the Ecuadorian páramo. Our results indicated that GPR was successful in quantifying peat depths and carbon stocks. Detection of volcanic horizons like tephra layers allowed further refinement of variability of C stocks within the peat column, while providing information on the lateral extent of tephras at high (centimeter-scale) resolution that may prove very useful for the correlation of time-stratigraphic markers between sediments in alpine peatlands. In conclusion, this paper provides a methodological basis for quantifying C stocks in high-altitude peatlands and to infer changes in the physical properties of soils that could be used as proxies for C content or paleoclimate reconstructions.

  3. Spatial variability of active layer thickness detected by ground-penetrating radar in the Qilian Mountains, Western China

    Science.gov (United States)

    Cao, Bin; Gruber, Stephan; Zhang, Tingjun; Li, Lili; Peng, Xiaoqing; Wang, Kang; Zheng, Lei; Shao, Wanwan; Guo, Hong

    2017-03-01

    The active layer plays a key role in geomorphic, hydrologic, and biogeochemical processes in permafrost regions. We conducted a systematic investigation of active layer thickness (ALT) in northeastern Qinghai-Tibetan Plateau by using ground-penetrating radar (GPR) with 100 and 200 MHz antennas. We used mechanical probing, pit, and soil temperature profiles for evaluating ALT derived from GPR. The results showed that GPR is competent for detecting ALT, and the error was ±0.08 m at common midpoint co-located sites. Considerable spatial variability of ALT owing to variation in elevation, peat thickness, and slope aspect was found. The mean ALT was 1.32 ± 0.29 m with a range from 0.81 to 2.1 m in Eboling Mountain. In Yeniu Gou, mean ALT was 2.72 ± 0.88 m and varied from 1.07 m on the north-facing slope to 4.86 m around the area near the lower boundary of permafrost. ALT in peat decreased with increasing elevation at rates of -1.31 m/km (Eboling Mountain) and -2.1 m/km (Yeniu Gou), and in mineral soil in Yeniu Gou, the rate changed to -4.18 m/km. At the same elevation, ALT on the south-facing slope was about 0.8 m thicker than that on the north-facing slopes, while the difference was only 0.18 m in peat-covered area. Within a 100 m2 area with a local elevation difference of 0.8 m, ALT varied from 0.68 m to 1.25 m. Both field monitoring and modeling studies on spatial ALT variations require rethinking of the current strategy and comprehensive design.

  4. Using Ground-Penetrating Radar to Estimate Sediment Accumulation in a Reservoir: Ball Mountain Dam, West River, Vermont

    Science.gov (United States)

    Kasprak, A.; Arcone, S. A.; Dade, W. B.; Finnegan, D. C.; Magilligan, F. J.; Renshaw, C. E.

    2008-12-01

    Numerous dams exist throughout the Upper Connecticut River watershed, having profound effects on regional sediment budgets for the past 50+ years. We use ground-penetrating radar (GPR) to investigate sediment deposition by the West River into an impoundment reservoir located in southern Vermont, with the aim of determining the watershed-scale sediment budget and examining regional denudation rates. The reservoir has a storage capacity of ~104,000,000 cubic meters and was created in 1961 as a consequence of the construction of Ball Mountain Dam in Jamaica, Vermont. A total of 33 GPR reflection profiles were obtained with a 200-MHz radar antenna towed in a raft behind a boat, with 19 additional 100 MHz profiles obtained along exposed shorelines at minimal water level. Preliminary analyses indicate vertical sediment deposition varies greatly based on location; some areas of the impoundment show almost no overlying sediment, while others have received 5 meters of deposition or more. Minimal sediment accumulation is apparent on both the flat bed located along the centerline of the impoundment and on steeply-inclined submerged bedrock faces. Maximum deposition appears to be occurring along shallow-dipping subaqueous slopes near the edges of the reservoir. On-going work includes continued interpretation of GPR records, ground-truthing of those records through sediment coring, and calculation of sediment accumulation rates. In addition to defining the watershed-scale sediment budget over a decadal time scale, results may help guide policy-making regarding the upkeep and potential removal of dams in the region.

  5. Synthetic aperture acoustic imaging of canonical targets with a 2-15 kHz linear FM chirp

    Science.gov (United States)

    Vignola, Joseph F.; Judge, John A.; Good, Chelsea E.; Bishop, Steven S.; Gugino, Peter M.; Soumekh, Mehrdad

    2011-06-01

    Synthetic aperture image reconstruction applied to outdoor acoustic recordings is presented. Acoustic imaging is an alternate method having several military relevant advantages such as being immune to RF jamming, superior spatial resolution, capable of standoff side and forward-looking scanning, and relatively low cost, weight and size when compared to 0.5 - 3 GHz ground penetrating radar technologies. Synthetic aperture acoustic imaging is similar to synthetic aperture radar, but more akin to synthetic aperture sonar technologies owing to the nature of longitudinal or compressive wave propagation in the surrounding acoustic medium. The system's transceiver is a quasi mono-static microphone and audio speaker pair mounted on a rail 5meters in length. Received data sampling rate is 80 kHz with a 2- 15 kHz Linear Frequency Modulated (LFM) chirp, with a pulse repetition frequency (PRF) of 10 Hz and an inter-pulse period (IPP) of 50 milliseconds. Targets are positioned within the acoustic scene at slant range of two to ten meters on grass, dirt or gravel surfaces, and with and without intervening metallic chain link fencing. Acoustic image reconstruction results in means for literal interpretation and quantifiable analyses. A rudimentary technique characterizes acoustic scatter at the ground surfaces. Targets within the acoustic scene are first digitally spotlighted and further processed, providing frequency and aspect angle dependent signature information.

  6. Computational dynamics of acoustically-driven microsphere systems

    CERN Document Server

    Glosser, Connor A; Dault, Daniel L; Piermarocchi, Carlo; Shanker, Balasubramaniam

    2015-01-01

    We propose a computational framework for the self-consistent dynamics of a microsphere system driven by a pulsed acoustic field in an ideal fluid. Our framework combines a molecular dynamics integrator describing the dynamics of the microsphere system with a time-dependent integral equation solver for the acoustic field that makes use of fields represented as surface expansions in spherical harmonic basis functions. The presented approach allows us to describe the inter-particle interaction induced by the field as well as the dynamics of trapping in counter-propagating acoustic pulses. The integral equation formulation leads to equations of motion for the microspheres describing the effect of non-dissipative drag forces. We show (1) that the field-induced interactions between the microspheres give rise to effective dipolar interactions, with effective dipoles defined by their velocities, and (2) that the dominant effect of an ultrasound pulse through a cloud of microspheres gives rise mainly to a translation ...

  7. Numerical simulation of a laser-acoustic landmine detection system

    Science.gov (United States)

    Lancranjan, Ion I.; Miclos, Sorin; Savastru, Dan; Savastru, Roxana; Opran, Constantin

    2012-06-01

    The preliminary numerical simulation results obtained in the analysis of a landmine detection system based on laser excitation of acoustic - seismic waves in the soil and observing its surface vibration above the embedded landmine are presented. The presented numerical simulations comprise three main parts: 1) Laser oscillator and laser beam propagation and absorption in soil; a laser oscillator operated in Q-switched regime is considered; different laser wavelengths are investigated. 2) Acoustic - seismic wave generation by absorption in soil of laser pulse energy; 3) Evaluation of acoustic - seismic wave generation by the buried in soil landmine; 4) Comparison of Distributed Feed- Back Fiber Laser (DFB-FL) and Laser Doppler Vibrometer (LDV) detector used for soil vibrations evaluation. The above mentioned numerical simulation is dedicated for evaluation of an integrated portable detection system.

  8. Performance Evaluation of a Biometric System Based on Acoustic Images

    Directory of Open Access Journals (Sweden)

    Juan J. Villacorta

    2011-10-01

    Full Text Available An acoustic electronic scanning array for acquiring images from a person using a biometric application is developed. Based on pulse-echo techniques, multifrequency acoustic images are obtained for a set of positions of a person (front, front with arms outstretched, back and side. Two Uniform Linear Arrays (ULA with 15 l/2-equispaced sensors have been employed, using different spatial apertures in order to reduce sidelobe levels. Working frequencies have been designed on the basis of the main lobe width, the grating lobe levels and the frequency responses of people and sensors. For a case-study with 10 people, the acoustic profiles, formed by all images acquired, are evaluated and compared in a mean square error sense. Finally, system performance, using False Match Rate (FMR/False Non-Match Rate (FNMR parameters and the Receiver Operating Characteristic (ROC curve, is evaluated. On the basis of the obtained results, this system could be used for biometric applications.

  9. Acoustic wave propagation in high-pressure system.

    Science.gov (United States)

    Foldyna, Josef; Sitek, Libor; Habán, Vladimír

    2006-12-22

    Recently, substantial attention is paid to the development of methods of generation of pulsations in high-pressure systems to produce pulsating high-speed water jets. The reason is that the introduction of pulsations into the water jets enables to increase their cutting efficiency due to the fact that the impact pressure (so-called water-hammer pressure) generated by an impact of slug of water on the target material is considerably higher than the stagnation pressure generated by corresponding continuous jet. Special method of pulsating jet generation was developed and tested extensively under the laboratory conditions at the Institute of Geonics in Ostrava. The method is based on the action of acoustic transducer on the pressure liquid and transmission of generated acoustic waves via pressure system to the nozzle. The purpose of the paper is to present results obtained during the research oriented at the determination of acoustic wave propagation in high-pressure system. The final objective of the research is to solve the problem of transmission of acoustic waves through high-pressure water to generate pulsating jet effectively even at larger distances from the acoustic source. In order to be able to simulate numerically acoustic wave propagation in the system, it is necessary among others to determine dependence of the sound speed and second kinematical viscosity on operating pressure. Method of determination of the second kinematical viscosity and speed of sound in liquid using modal analysis of response of the tube filled with liquid to the impact was developed. The response was measured by pressure sensors placed at both ends of the tube. Results obtained and presented in the paper indicate good agreement between experimental data and values of speed of sound calculated from so-called "UNESCO equation". They also show that the value of the second kinematical viscosity of water depends on the pressure.

  10. A chaotic spread spectrum system for underwater acoustic communication

    Science.gov (United States)

    Ren, Hai-Peng; Bai, Chao; Kong, Qingju; Baptista, Murilo S.; Grebogi, Celso

    2017-07-01

    Acoustic communication is a key technology to exchange information underwater, which is of great significance to explore marine resources and to marine defense. The underwater acoustic channel is a time-space-frequency varying channel characterized by serious multipath effect, limited frequency band, complex environmental noises and significant Doppler frequency shift phenomenon, which makes underwater acoustic communication with low Bit Error Rate (BER) to be a challenging task. A novel chaotic spread spectrum acoustic communication method with low BER is proposed in this paper. A chaotic signal, generated by a hybrid dynamical system, is used as a spread spectrum sequence at the transmitter end. At the receiver end, a corresponding chaotic matched filter is used to offset the effect of multipath propagation and noise. The proposed method does not require the complicated equalization and modulation-demodulation technologies that are necessary for conventional acoustic communication. Simulation results show that the proposed method has good anti-interference ability and lower BER as compared to other traditional methods.

  11. Design and performance analysis of digital acoustic underwater telemetry system

    Science.gov (United States)

    Catipovic, J. A.; Baggeroer, A. B.; Vonderheydt, K.; Koelsch, D. E.

    1985-11-01

    The work discusses the design and performance characteristics of a Digital Acoustic Telemetry System (DATS) which incorporates the current state-of-the-art technology and is capable of reliable data transmission at rates useful to a wide range of ocean exploration and development gear.

  12. Underwater Acoustic Image Transmission System Based on DSP

    Institute of Scientific and Technical Information of China (English)

    Cheng En; Xu Ru

    2002-01-01

    The underwater acoustic image transmission system based on the high-speed DSP device TMS320C549 has been studied. We use Goertzel algorithm for source decoding and MFSK for modulation. Turbo code is used for channel coding and decoding. The purpose is to implement underwater video image data transmission.

  13. Optimisation of acoustic silencer for the screw compressor system

    NARCIS (Netherlands)

    Swamy, M.; Lier, L.J. van; Smeulers, J.P.M.

    2014-01-01

    In one of the screw compressor system, designed silencer was not optimal. A great challenge was the large variation in operating conditions, especially the variation of the molecular weight of the gas. There was need to optimize the silencer. This paper describes the acoustic modelling tools to

  14. Optimisation of acoustic silencer for the screw compressor system

    NARCIS (Netherlands)

    Swamy, M.; Lier, L.J. van; Smeulers, J.P.M.

    2014-01-01

    In one of the screw compressor system, designed silencer was not optimal. A great challenge was the large variation in operating conditions, especially the variation of the molecular weight of the gas. There was need to optimize the silencer. This paper describes the acoustic modelling tools to opti

  15. Material Property Estimation for Direct Detections of DNAPL using Integrated Ground-Penetrating Radar Velocity, Imaging and Attribute Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Bradford, John; Smithson, Scott B.; Holbrook, W. Stephen

    2004-06-14

    The focus of our work is direct detection of DNAPLs, specifically chlorinated solvents, via material property estimation from surface ground-penetrating radar (GPR) data. We combine sophisticated GPR processing methodology with quantitative attribute analysis and material property estimation to determine the location and extent of residual and/or pooled DNAPL in both the vadose and saturated zones. An important byproduct of our research is state-of-the-art imaging which allows us to pinpoint attribute anomalies, characterize stratigraphy, identify fracture zones, and locate buried objects. Implementation and verification of these methodologies will be a significant advance in GPR research and in meeting DOE's need for reliable in-situ characterization of DNAPL contamination. Chlorinated solvents have much lower electric permittivity and conductivity than water. An electrical property contrast is induced when solvents displace water in the sediment column resulting in an anomalous GPR signature. To directly identify zones of DNAPL contamination, we focus on three aspects of reflected wave behavior--propagation velocity, frequency dependent attenuation, and amplitude variation with offset (AVO). Velocity analysis provides a direct estimate of electric permittivity, attenuation analysis provides a measure of conductivity, and AVO behavior is used to estimate the permittivity ratio at a reflecting boundary. Areas of anomalously low electric permittivity and conductivity are identified as potential DNAPL rich zones. Preliminary work illustrated significant potential for quantitative direct detection methodologies in identifying shallow DNAPL source zones. It is now necessary to verify these methodologies in a field setting. To this end, the project is field oriented and has three primary objectives: (1) Develop a suite of methodologies for direct detection of DNAPLs from surface GPR data (2) Controlled field verification at well characterized, contaminated sites (3

  16. Material Property Estimation for Direct Detection of DNAPL using Integrated Ground-Penetrating Radar Velocity, Imaging and Attribute Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Bradford, John; Smithson, Scott B.; Holbrook, W. Stephen

    2003-06-01

    The focus of our work is direct detection of DNAPLs, specifically chlorinated solvents, via material property estimation from surface ground-penetrating radar (GPR) data. We combine sophisticated GPR processing methodology with quantitative attribute analysis and material property estimation to determine the location and extent of residual and/or pooled DNAPL in both the vadose and saturated zones. An important byproduct of our research is state-of-the-art imaging which allows us to pinpoint attribute anomalies, characterize stratigraphy, identify fracture zones, and locate buried objects. Implementation and verification of these methodologies will be a significant advance in GPR research and in meeting DOE's need for reliable in-situ characterization of DNAPL contamination. Chlorinated solvents have much lower electric permittivity and conductivity than water. An electrical property contrast is induced when solvents displace water in the sediment column resulting in an anomalous GPR signature. To directly identify zones of DNAPL contamination, we focus on three aspects of reflected wave behavior--propagation velocity, frequency dependent attenuation, and amplitude variation with offset (AVO). Velocity analysis provides a direct estimate of electric permittivity, attenuation analysis provides a measure of conductivity, and AVO behavior is used to estimate the permittivity ratio at a reflecting boundary. Areas of anomalously low electric permittivity and conductivity are identified as potential DNAPL rich zones. Preliminary work illustrated significant potential for quantitative direct detection methodologies in identifying shallow DNAPL source zones. It is now necessary to verify these methodologies in a field setting. To this end, the project is field oriented and has three primary objectives: (1) Develop a suite of methodologies for direct detection of DNAPLs from surface GPR data (2) Controlled field verification at well characterized, contaminated sites (3

  17. Material Property Estimation for Direct Detection of DNAPL using Integrated Ground-Penetrating Radar Velocity, Imaging and Attribute Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Bradford, John; Smithson, Scott B.; Holbrook, Stephen

    2001-06-01

    The focus of our work is direct detection of DNAPLs, specifically chlorinated solvents, via material property estimation from surface ground-penetrating radar (GPR) data. We combine sophisticated GPR processing methodology with quantitative attribute analysis and material property estimation to determine the location and extent of residual and/or pooled DNAPL in both the vadose and saturated zones. An important byproduct of our research is state-of-the-art imaging which allows us to pinpoint attribute anomalies, characterize stratigraphy, identify fracture zones, and locate buried objects. Implementation and verification of these methodologies will be a significant advance in GPR research and in meeting DOE's need for reliable in-situ characterization of DNAPL contamination. Chlorinated solvents have much lower electric permittivity and conductivity than water. An electrical property contrast is induced when solvents displace water in the sediment column resulting in an anomalous GPR signature. To directly identify zones of DNAPL contamination, we focus on three aspects of reflected wave behavior--propagation velocity, frequency dependent attenuation, and amplitude variation with offset (AVO). Velocity analysis provides a direct estimate of electric permittivity, attenuation analysis provides a measure of conductivity, and AVO behavior is used to estimate the permittivity ratio at a reflecting boundary. Areas of anomalously low electric permittivity and conductivity are identified as potential DNAPL rich zones. Preliminary work illustrated significant potential for quantitative direct detection methodologies in identifying shallow DNAPL source zones. It is now necessary to verify these methodologies in a field setting. To this end, the project is field oriented and has three primary objectives: (1) Develop a suite of methodologies for direct detection of DNAPLs from surface GPR data (2) Controlled field verification at well characterized, contaminated sites (3

  18. Controlling acoustic wave with cylindrically-symmetric gradient-index system

    Institute of Scientific and Technical Information of China (English)

    张哲; 李睿奇; 梁彬; 邹欣晔; 程建春

    2015-01-01

    We present a detailed theoretical description of wave propagation in an acoustic gradient-index system with cylindrical symmetry and demonstrate its potential numerically to control acoustic waves in different ways. The trajectory of acoustic wave within the system is derived by employing the theory of geometric acoustics, and the validity of the theoretical descriptions is verified numerically by using the finite element method simulation. The results show that by tailoring the distribution function of refractive index, the proposed system can yield tunable manipulation on acoustic waves, such as acoustic bending, trapping, and absorbing.

  19. Acoustic FMRI noise: linear time-invariant system model.

    Science.gov (United States)

    Rizzo Sierra, Carlos V; Versluis, Maarten J; Hoogduin, Johannes M; Duifhuis, Hendrikus Diek

    2008-09-01

    Functional magnetic resonance imaging (fMRI) enables sites of brain activation to be localized in human subjects. For auditory system studies, however, the acoustic noise generated by the scanner tends to interfere with the assessments of this activation. Understanding and modeling fMRI acoustic noise is a useful step to its reduction. To study acoustic noise, the MR scanner is modeled as a linear electroacoustical system generating sound pressure signals proportional to the time derivative of the input gradient currents. The transfer function of one MR scanner is determined for two different input specifications: 1) by using the gradient waveform calculated by the scanner software and 2) by using a recording of the gradient current. Up to 4 kHz, the first method is shown as reliable as the second one, and its use is encouraged when direct measurements of gradient currents are not possible. Additionally, the linear order and average damping properties of the gradient coil system are determined by impulse response analysis. Since fMRI is often based on echo planar imaging (EPI) sequences, a useful validation of the transfer function prediction ability can be obtained by calculating the acoustic output for the EPI sequence. We found a predicted sound pressure level (SPL) for the EPI sequence of 104 dB SPL compared to a measured value of 102 dB SPL. As yet, the predicted EPI pressure waveform shows similarity as well as some differences with the directly measured EPI pressure waveform.

  20. Wire-grid electromagnetic modelling of metallic cylindrical objects with arbitrary section, for Ground Penetrating Radar applications

    Science.gov (United States)

    Adabi, Saba; Pajewski, Lara

    2014-05-01

    Authors demonstrated that the well-known same-area criterion yields affordable results but is quite far from being the optimum: better results can be obtained with a wire radius shorter than what is suggested by the rule. In utility detection, quality controls of reinforced concrete, and other civil-engineering applications, many sought targets are long and thin: in these cases, two-dimensional scattering methods can be employed for the electromagnetic modelling of scenarios. In the present work, the freeware tool GPRMAX2D [6], implementing the Finite-Difference Time-Domain method, is used to implement the wire-grid modelling of buried two-dimensional objects. The source is a line of current, with Ricker waveform. Results obtained in [5] are confirmed in the time domain and for different geometries. The highest accuracy is obtained by shortening the radius of about 10%. It seems that fewer (and larger) wires need minor shortening; however, more detailed investigations are required. We suggest to use at least 8 - 10 wires per wavelength if the field scattered by the structure has to be evaluated. The internal field is much more sensitive to the modelling configuration than the external one, and more wires should be employed when shielding effects are concerned. We plan to conduct a more comprehensive analysis, in order to extract guidelines for wire sizing, to be validated on different shapes. We also look forward to verifying the possibility of using the wire-grid modelling method for the simulation of slotted objects. This work is a contribution to COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar". The Authors thanks COST for funding COST Action TU1208. References [1] J.H. Richmond, A wire grid model for scattering by conducting bodies, IEEE Trans. Antennas Propagation AP-14 (1966), pp. 782-786. [2] S.M. Rao, D.R. Wilton, A.W. Glisson, Electromagnetic scattering by surfaces of arbitrary shape, IEEE Trans. Antennas Propagation AP-30 (1982

  1. Sound attenuation using microelectromechanical systems fabricated acoustic metamaterials

    Science.gov (United States)

    Yunker, William N.; Stevens, Colin B.; Flowers, George T.; Dean, Robert N.

    2013-01-01

    Unlike traditional rotational gyroscopes, microelectromechanical systems (MEMS) gyroscopes use a vibrating proof mass rather than a rotational mass to sense changes in angular rate. They are also smaller and less expensive than traditional gyroscopes. MEMS gyroscopes are known to be susceptible to the effects of acoustic noise, in particular high frequency and high power acoustic noise. Most notably, this has been proven true in aerospace applications where the noise can reach levels in excess of 120 dB and the noise frequency can exceed 20 kHz. The typical resonant frequency for the proof mass of a MEMS gyroscope is between 3 and 20 kHz. High power, high frequency acoustic noise can disrupt the output signal of the gyroscope to the point that the output becomes unreliable. In recent years, considerable research has focused on the fascinating properties found in metamaterials. A metamaterial is an artificially fabricated device or structure that is engineered to produce desired material responses that can either mimic known behaviors or produce responses that do not occur naturally in materials found in nature. Acoustic metamaterials, in particular, have shown great promise in the field of sound attenuation. This paper proposes a method to mitigate the performance degradation of the MEMS gyroscope in the presence of high power, high frequency acoustic noise by using a new acoustic metamaterial in the form of a two-dimensional array of micromachined Helmholtz resonators. The Helmholtz resonators are fabricated in a silicon wafer using standard MEMS manufacturing techniques and are designed to attenuate sound at the resonant frequency of the gyroscope proof mass. The resonator arrays were diced from the silicon wafer in one inch squares and assembled into a box open on one end in a manner to attenuate sound on all sides of the gyroscope, and to seal the gyroscope inside the box. The resulting acoustic metamaterial device was evaluated in an acoustic chamber and was

  2. Acoustic Model Adaptation for Indonesian Language Utterance Training System

    Directory of Open Access Journals (Sweden)

    Linda Indrayanti

    2010-01-01

    Full Text Available Problem statement: In order to build an utterance training system for Indonesian language, a speech recognition system designed for Indonesian is necessary. However, the system hardly works well due to the pronunciation variants of non-native utterances may lead to substitution/deletion error. This research investigated the pronunciation variant and proposes acoustic model adaptation to improve performance of the system. Approach: The proposed acoustic model adaptation worked in three steps: to analyze pronunciation variant with knowledge-based and data-derived methods; to align knowledge-based and data-derived results in order to list frequently mispronounced phones with their variants; to perform a state-clustering procedure with the list obtained from the second step. Further, three Speaker Adaptation (SA techniques were used in combination with the acoustic model adaptation and they are compared each other. In order to evaluate and tune the adaptation techniques, perceptual-based evaluation by three human raters is performed to obtain the "true"recognition results. Results: The proposed method achieved an average gain in Hit + Rejection (the percentage of correctly accepted and correctly rejected utterances by the system as the human raters do of 2.9 points and 2 points for native and non-native subjects, respectively, when compared with the system without adaptation. Average gains of 12.7 and 6.2 points for native and non-native students in Hit + Rejection were obtained by combining SA to the acoustic model adaptation. Conclusion/Recommendations: Performance evaluation of the adapted system demonstrated that the proposed acoustic model adaptation can improve Hit even though there is a slight increase of False Alarm (FA, the percentage of incorrectly accepted utterances by the system of which the human raters reject. The performance of the proposed acoustic model adaptation depends strongly on the effectiveness of state-clustering procedure

  3. Simple model of photo acoustic system for greenhouse effect

    CERN Document Server

    Fukuhara, Akiko; Ogawa, Naohisa

    2010-01-01

    The simple theoretical basis for photo acoustic (PA) system for studying infrared absorption properties of greenhouse gases is constructed. The amplitude of sound observed in PA depends on the modulation frequency of light pulse. Its dependence can be explained by our simple model. According to this model, sound signal has higher harmonics. The theory and experiment are compared in third and fifth harmonics by spectrum analysis. The theory has the analogy with electric circuits. This analogy helps students for understanding the PA system.

  4. Computational modeling of on-contact antennas for the detection and localization of anti-personnel landmines via ground penetrating radar

    Science.gov (United States)

    Hines, Margery Jeanne

    Ground-penetrating radar (GPR) is a mature technology which has developed into a popular tool for subsurface imaging; however its application in landmine detection is still in its infancy. Landmines are typically buried in dispersive soils below a rough surface where the effectiveness of conventional air-coupled GPR is limited. By utilizing ground-contact antennas the signal penetration is dramatically improved and data analysis is simplified. In order to canvas an area while achieving ground-contact with the antennas, this research proposes that the antennas be mounted to the bottom of the feet of a walking robotic platform developed by Square One Systems Design, called the Tri-Sphere Multi-Mode Mobility Platform. Using three antennas in both the transmitting and receiving modes, three unique bistatic GPR traces can be obtained from which a novel anti-personnel landmine detection and localization method is proposed. For each GPR trace, the target reflection is enhanced using circular polarization and is extracted using background removal. The full-path travel times are then determined by correlating the target reflections with a reference signal. These travel times are used to geometrically determine the target position to a single subsurface scattering point, which is identified as the potential target location. This detection method is fully autonomous, thereby allowing the robot to canvas a large amount of area and mark potential threats without any human interaction. Using a 3-dimensional finite-difference time domain model, GPR data is simulated for sixteen statistically different rough surfaces, nine different target locations, and two target casings, amounting to 288 unique simulations. The soil modeled is 10% wet Bosnian soil, which is both lossy and dispersive. For comparison, the various simulations are analyzed with both the exact simulated background response and the statistically approximated background response. Ultimately, using the approximated

  5. Study of acoustic signal in the process of resistance spot welding based on array sensor system

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This investigation was performed to study acoustic field signal in order to improve RSW quality. Researchers firstly built an acoustic array sensor system, which included 8 MPA-416 acoustic sensors, data acquisition card and LabVIEW. The system obtained the acoustic field information in the process of nugget growing. Due to the nonlinearity field signal, array sensor algorithm was utilized to quantitatively analyze the characteristics of acoustic field and reduced noise. The experiment and calculation results show that array sensor system can acquire acoustic field signal of nugget growing in the RSW process and array processing algorithm based on acoustic field can extract characteristic parameters to evaluate RSW quality. It was concluded that the acoustic array sensor system offers a new methodology for RSW quality inspection.

  6. Acoustic monitoring systems tests at Indian Point Unit 1. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Smith, J.R.; Rao, G.V.; Craig, J.

    1979-12-01

    This report describes the results of a program to test acoustic monitoring systems on Indian Point Unit No. 1 under actual plant operating conditions, less the reactor core. The two types of systems evaluated were the monitoring of acoustic emissions generated by growing flaws and the monitoring of acoustic signals from leaks.

  7. Geophysical Investigation of Subsurface Characteristics of Icy Debris Fans with Ground Penetrating Radar in the Wrangell Mountains, Alaska

    Science.gov (United States)

    Smith, T. D.; Jacob, R. W.

    2013-12-01

    Authors Tracey Smith^1, Rob Jacob^1, Jeffrey Trop^1, Keith Williams^2 and Craig Kochel^1 Bucknell University, Geology and Environmental Geoscience Department, Lewisburg, PA UNAVCO, 6350 Nautilus Dr., Boulder, CO 80301 Icy debris fans have recently been described as deglaciation features on Earth and similar features have been observed on Mars, however, the subsurface characteristics remain unknown. We used ground penetrating radar (GPR) to non-invasively investigate the subsurface characteristics of icy debris fans near McCarthy, Alaska, USA. The three fans investigated in Alaska are the East, West, and Middle fans which are between the Nabesna ice cap and the McCarthy Glacier. Icy debris fans in general are a largely unexplored suite of paraglacial landforms and processes in alpine regions. Recent field studies focused on direct observations and depositional processes. The results showed that each fan's composition is primarily influenced by the type and frequency of mass wasting processes that supply the fan. Photographic studies show that the East fan receives far more ice and snow avalanches whereas the Middle and West fan receive fewer mass wasting events but more clastic debris is deposited on the Middle and West fan from rock falls and icy debris flows. GPR profiles and WARR surveys consisting of both, common mid-point (CMP), and common shot-point (CSP) surveys investigated the subsurface geometry of the fans and the McCarthy Glacier.All GPR surveys were collected in 2013 with 100MHz bi-static antennas. Four axial profiles and three cross-fan profiles were done on the West and Middle fans as well as the McCarthy Glacier in order to investigate the relationship between the three features. Terrestrial laser surveying of the surface and real-time kinematic GPS provided the surface elevation used to correct the GPR data for topographic changes. GPR profiles yielded reflectors that were continuous for 10+ m and hyperbolic reflections in the subsurface. The WARR

  8. Ground Penetrating Radar Field Studies of Lunar-Analog Geologic Settings and Processes: Barringer Meteor Crater and Northern Arizona Volcanics

    Science.gov (United States)

    Russell, P. S.; Grant, J. A.; Williams, K. K.; Bussey, B.

    2010-12-01

    Ground-Penetrating Radar (GPR) data from terrestrial analog environments can help constrain models for evolution of the lunar surface, aid in interpretation of orbital SAR data, and help predict what might be encountered in the subsurface during future, landed, scientific or engineering operations on the Moon. GPR can yield insight into the physical properties, clast-size distribution, and layering of the subsurface, granting a unique view of the processes affecting an area over geologic time. The purpose of our work is to demonstrate these capabilities at sites at which geologic processes, settings, and/or materials are similar to those that may be encountered on the moon, especially lava flows, impact-crater ejecta, and layered materials with varying properties. We present results from transects obtained at Barringer Meteor Crater, SP Volcano cinder cone, and Sunset Crater Volcano National Monument, all in northern Arizona. Transects were taken at several sites on the ejecta of Meteor Crater, all within a crater radius (~400 m) of the crater rim. Those taken across ejecta lobes or mounds reveal the subsurface contact of the ejecta upper surface and overlying, embaying sediments deposited by later alluvial, colluvial, and/or aeolian processes. Existing mine shafts and pits on the south side of the crater provide cross sections of the subsurface against which we compare adjacent GPR transects. The ‘actual’ number, size, and depth of clasts in the top 1-2 m of the subsurface are estimated from photos of the exposed cross sections. In GPR radargrams, reflections attributed to blocks in the top 2-5 m of the subsurface are counted, and their depth distribution noted. Taking GPR measurements along a transect at two frequencies (200 and 400 MHz) and to various depths, we obtain the ratio of the actual number of blocks in the subsurface to the number detectable with GPR, as well as an assessment of how GPR detections in ejecta decline with depth and depend on antenna

  9. Real-time system for studies of the effects of acoustic feedback on animal vocalizations.

    Directory of Open Access Journals (Sweden)

    Mike eSkocik

    2013-01-01

    Full Text Available Studies of behavioral and neural responses to distorted auditory feedback can help shed light on the neural mechanisms of animal vocalizations. We describe an apparatus for generating real-time acoustic feedback. The system can very rapidly detect acoustic features in a song and output acoustic signals if the detected features match the desired acoustic template. The system uses spectrogram-based detection of acoustic elements. It is low-cost and can be programmed for a variety of behavioral experiments requiring acoustic feedback or neural stimulation. We use the system to study the effects of acoustic feedback on birds' vocalizations and demonstrate that such an acoustic feedback can cause both immediate and long-term changes to birds’ songs.

  10. A System for Acoustic Field Measurement Employing Cartesian Robot

    Directory of Open Access Journals (Sweden)

    Szczodrak Maciej

    2016-09-01

    Full Text Available A system setup for measurements of acoustic field, together with the results of 3D visualisations of acoustic energy flow are presented in the paper. Spatial sampling of the field is performed by a Cartesian robot. Automatization of the measurement process is achieved with the use of a specialized control system. The method is based on measuring the sound pressure (scalar and particle velocity(vector quantities. The aim of the system is to collect data with a high precision and repeatability. The system is employed for measurements of acoustic energy flow in the proximity of an artificial head in an anechoic chamber. In the measurement setup an algorithm for generation of the probe movement path is included. The algorithm finds the optimum path of the robot movement, taking into account a given 3D object shape present in the measurement space. The results are presented for two cases, first without any obstacle and the other - with an artificial head in the sound field.

  11. Study on demodulated signal distribution and acoustic pressure phase sensitivity of a self-interfered distributed acoustic sensing system

    Science.gov (United States)

    Shang, Ying; Yang, Yuan-Hong; Wang, Chen; Liu, Xiao-Hui; Wang, Chang; Peng, Gang-Ding

    2016-06-01

    We propose a demodulated signal distribution theory for a self-interfered distributed acoustic sensing system. The distribution region of Rayleigh backscattering including the acoustic sensing signal in the sensing fiber is investigated theoretically under different combinations of both the path difference and pulse width Additionally we determine the optimal solution between the path difference and pulse width to obtain the maximum phase change per unit length. We experimentally test this theory and realize a good acoustic pressure phase sensitivity of  -150 dB re rad/(μPa·m) of fiber in the frequency range from 200 Hz to 1 kHz.

  12. Effects of spatially variable snow cover on thermal regime and hydrology of an Arctic ice wedge polygon landscape identified using ground penetrating radar and LIDAR datasets

    Science.gov (United States)

    Gusmeroli, A.; Liljedahl, A. K.; Peterson, J. E.; Hubbard, S. S.; Hinzman, L. D.

    2012-12-01

    Ice wedge polygons are common in Arctic terrains underlain by permafrost. Permafrost degradation could transform low- into high centered polygons, causing profound changes in the hydrologic regime of Arctic lands, which in turn, could affect the energy balance and subsurface biodegradation of organic carbon responsible for greenhouse gas production. Understanding the linkages between microtopography, snow cover, thermal properties, and thaw depth is critical for developing a predictive understanding of terrestrial ecosystems and their feedbacks to climate. In this study, we use high frequency (500-1000 MHz) ground penetrating radar (GPR) data acquired in spring 2012 within the Next Generation Ecosystem Experiment (NGEE) study site in Barrow, AK to characterize the spatial variability of snow distribution. We compare it's distribution to microtopography, estimated using LIDAR data, and thaw depth, also estimated using ground penetrating radar collected at different times during the year and simulated over time using mechanistic thermal-hydrologic modeling. The high spatial resolution offered by LIDAR and ground penetrating radar permit detailed investigations of the control of microtopography on snow and thaw layer depth. Results suggest that microtopographical variations are responsible for substantial differences in snow accumulation. In low centered polygons, snow depth can be up to four times greater in the troughs than on the rims. Both modeling and observations suggest that the microtopography-governed snow thickness affects the thermal properties of the subsurface and thus the thaw layer thickness; regions with thicker snowpack generally correspond to regions of greater thaw depth. We conclude that a transition from low- to high centered polygons will not only impact watershed runoff but, since snow accumulation is sensitive to the microtopography, it will also impact snow distribution. In turn, snow distribution affects thaw depth thickness, and the

  13. Study on the Ground Penetrating Radar Detecting Air-raid Shelter%探地雷达对地下防空洞的探测研究

    Institute of Scientific and Technical Information of China (English)

    谷松

    2011-01-01

    Based on Ground Penetrating Radar (GPR) technology application, the paper summarizes the basic working principle of the GPR and its application on detecting the air-raid shelter in the Gaode Dongshan, Fuxin City. By positioning the goal body, the GPR technology can survey air-raid shelter accurate position. Furthermore, the GPR technology can provide the technical support to effectively safeguard underground constructs.%本文简述了探地雷达技术的基本原理及其在阜新高德东山探测防空洞的应用。

  14. SURFACE GEOPHYSICAL EXPLORATION OF TX-TY TANK FARMS AT THE HANFORD SITE RESULTS OF BACKGROUND CHARACTERIZATION WITH GROUND PENETRATING RADAR

    Energy Technology Data Exchange (ETDEWEB)

    MYERS DA; CUBBAGE R; BRAUCHLA R; O' BRIEN G

    2008-07-24

    Ground penetrating radar surveys of the TX and TY tank farms were performed to identify existing infrastructure in the near surface environment. These surveys were designed to provide background information supporting Surface-to-Surface and Well-to-Well resistivity surveys of Waste Management Area TX-TY. The objective of the preliminary investigation was to collect background characterization information with GPR to understand the spatial distribution of metallic objects that could potentially interfere with the results from high resolution resistivity{trademark} surveys. The results of the background characterization confirm the existence of documented infrastructure, as well as highlight locations of possible additional undocumented subsurface metallic objects.

  15. Acoustic Self-Calibrating System for Indoor Smart Phone Tracking

    Directory of Open Access Journals (Sweden)

    Alexander Ens

    2015-01-01

    Full Text Available This paper presents an acoustic indoor localization system for commercial smart phones that emit high pitched acoustic signals beyond the audible range. The acoustic signals with an identifier code modulated on the signal are detected by self-built receivers which are placed at the ceiling or on walls in a room. The receivers are connected in a Wi-Fi network, such that they synchronize their clocks and exchange the time differences of arrival (TDoA of the received chirps. The location of the smart phone is calculated by TDoA multilateration. The precise time measuring of sound enables high precision localization in indoor areas. Our approach enables applications that require high accuracy, such as finding products in a supermarket or guiding blind people through complicated buildings. We have evaluated our system in real-world experiments using different algorithms for calibration-free localization and different types of sound signals. The adaptive GOGO-CFAR threshold enables a detection of 48% of the chirp pulses even at a distance of 30 m. In addition, we have compared the trajectory of a pedestrian carrying a smart phone to reference positions of an optic system. Consequently, the localization error is observed to be less than 30 cm.

  16. Coupled Research in Ocean Acoustics and Signal Processing for the Next Generation of Underwater Acoustic Communication Systems

    Science.gov (United States)

    2015-11-20

    methodology within the framework of asymptotic random matrix theory (RMT) to explicitly model the time variability of acoustic channels and using...this to predict un- derwater acoustic communications systems performance. Specifically, current theory to date was applied to the problem of determining...and improvement in equaliza- tion performance. The theory was also applied to the problem of evaluating the relative performance of linear vs decision

  17. AMADEUS-The acoustic neutrino detection test system of the ANTARES deep-sea neutrino telescope

    NARCIS (Netherlands)

    Aguilar, J. A.; Al Samarai, I.; Albert, A.; Anghinolfi, M.; Anton, G.; Anvar, S.; Ardid, M.; Jesus, A. C. Assis; Astraatmadja, T.; Aubert, J. -J.; Auer, R.; Barbarito, E.; Baret, B.; Basa, S.; Bazzotti, M.; Bertin, V.; Biagi, S.; Bigongiari, C.; Bou-Cabo, M.; Bouwhuis, M. C.; Brown, A.; Brunner, J.; Busto, J.; Camarena, F.; Capone, A.; Carloganu, C.; Carminati, G.; Carr, J.; Cassano, B.; Castorina, E.; Cavasinni, V.; Cecchini, S.; Ceres, A.; Charvis, Ph.; Chiarusi, T.; Sen, N. Chon; Circella, M.; Coniglione, R.; Costantini, H.; Cottini, N.; Coyle, P.; Curtil, C.; De Bonis, G.; Decowski, M. P.; Dekeyser, I.; Deschamps, A.; Distefano, C.; Donzaud, C.; Dornic, D.; Drouhin, D.; Eberl, T.; Emanuele, U.; Ernenwein, J. -P.; Escoffier, S.; Fehr, F.; Fiorello, C.; Flaminio, V.; Fritsch, U.; Fuda, J. -L.; Gay, P.; Giacomelli, G.; Gomez-Gonzalez, J. P.; Graf, K.; Guillard, G.; Halladjian, G.; Hallewell, G.; van Haren, H.; Heijboer, A. J.; Heine, E.; Hello, Y.; Hernandez-Rey, J. J.; Herold, B.; Hoessl, J.; de Jong, M.; Kalantar-Nayestanaki, N.; Kalekin, O.; Kappes, A.; Katz, U.; Keller, P.; Kooijman, P.; Kopper, C.; Kouchneri, A.; Kretschmer, W.; Lahmann, R.; Lamare, P.; Lambard, G.; Larosa, G.; Laschinsky, H.; Le Provost, H.; Lefevre, D.; Lelaizant, G.; Lim, G.; Lo Presti, D.; Loehner, H.; Loucatos, S.; Louis, F.; Lucarelli, F.; Mangano, S.; Marcelin, M.; Margiotta, A.; Martinez-Mora, J. A.; Mazure, A.; Mongelli, M.; Montaruli, T.; Morganti, M.; Moscoso, L.; Motz, H.; Naumann, C.; Neff, M.; Ostasch, R.; Palioselitis, D.; Pavalas, G. E.; Payre, P.; Petrovic, J.; Picot-Clemente, N.; Picq, C.; Popa, V.; Pradier, T.; Presani, E.; Racca, C.; Radu, A.; Reed, C.; Riccobene, G.; Richardt, C.; Rujoiu, M.; Ruppi, M.; Russo, G. V.; Salesa, F.; Sapienza, P.; Schoeck, F.; Schuller, J. -P.; Shanidze, R.; Simeone, F.; Spurio, M.; Steijger, J. J. M.; Stolarczyk, Th.; Taiuti, M.; Tamburini, C.; Tasca, L.; Toscano, S.; Vallage, B.; Van Elewyck, V.; Vannoni, G.; Vecchi, M.; Vernin, P.; Wijnker, G.; de Wolf, E.; Yepes, H.; Zaborov, D.; Zornoza, J. D.; Zuniga, J.

    2011-01-01

    The AMADEUS (ANTARES Modules for the Acoustic Detection Under the Sea) system which is described in this article aims at the investigation of techniques for acoustic detection of neutrinos in the deep sea. It is integrated into the ANTARES neutrino telescope in the Mediterranean Sea. Its acoustic se

  18. Miniature acoustic wave lysis system and uses thereof

    Energy Technology Data Exchange (ETDEWEB)

    Branch, Darren W.; Vreeland, Erika Cooley; Smith, Gennifer Tanabe

    2016-12-06

    The present invention relates to an acoustic lysis system including a disposable cartridge that can be reversibly coupled to a platform having a small, high-frequency piezoelectric transducer array. In particular, the system releases viable DNA, RNA, and proteins from human or bacterial cells, without chemicals or additional processing, to enable high-speed sample preparation for clinical point-of-care medical diagnostics and use with nano/microfluidic cartridges. Also described herein are methods of making and using the system of the invention.

  19. Holocene relative sea level variations at the spit system Feddet (Denmark) resolved by ground-penetrating radar and geomorphological data

    DEFF Research Database (Denmark)

    Hede, Mikkel Ulfeldt; Bendixen, Mette; Clemmensen, Lars B;

    collected across beach ridge deposits from Feddet, eastern Denmark, and resolve past relative sea level with a relatively high precision. Feddet is a spit located in Faxe Bay (western part of the Baltic Sea) close to the current 0-isobase of isostatic rebound and is considered a key locality for studies...... in both the present beach face and upper shoreface deposits and in the interpreted beach face and upper shoreface GPR reflections. The break point marks the present transition from beach to upper shoreface and coincides with actual sea level within a few centimetres. Furthermore, our observations indicate...... that downlap points of deposits formed under both relatively high and low water levels are preserved and are identified in GPR reflection data. Thus, records of these sea-level markers constrain the local relative sea level history during the Holocene. Downlap points identified in GPR data across other...

  20. Comprehensive Application of Ground Penetrating Radar in Railway Engineering%地质雷达在铁路工程中的综合应用

    Institute of Scientific and Technical Information of China (English)

    刘亮; 蒲嘉霖

    2014-01-01

    近年来地质雷达法作为地球物理勘探的重要手段在铁路、水电、公路、城市工程、地下工程中得到了广泛应用。本文着重介绍SIR-2型地质雷达在铁路隧道施工勘察阶段、铁路隧道工程衬砌质量验收阶段和铁路运营维护管理中的可行性。%As an important method of geophysical exploration, ground penetrating radar has been widely applied in the railway, hydropower, roads, urban engineering and underground engineering in recent years. This paper mainly introduces the feasibility of SIR-2 ground penetrating radar in the prospecting stage of railway tunnel construction, quality acceptance stage of railway tunnel engineering lining and maintenance and management of railway operation.

  1. Ground penetration radar 3-D modelling using the finite difference technique; Modelagem tridimensional de dados de radar (GPR) usando a tecnica das diferencas finitas

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Rene Santos; Botelho, Marco Antonio Barsottelli [Bahia Univ., Salvador, BA (Brazil). Inst. de Geociencias. Programa de Pesquisa e Pos-graduacao em Geofisica

    1995-12-31

    The Ground Penetration Radar (GPR) is a surface-geophysical method that can produce continuous high-resolution profiles much better than seismic methods, but phenomena of propagation of the electromagnetic (EM) pulse can be of harder interpretation than seismic pulses. The phenomena of propagation of the EM waves in the air add more reflection on the GPR data gathers. In this work we illustrate this phenomena using 3-D models with structures above the ground. The 3-D synthetic common shot gathers are important tools to analyse the GPR response in order to improve the understanding of the geometry of overburden conditions for activities such as geotechnical investigations or factors controlling groundwater flow. Groups of 3-D synthetic common shot gathers of ground penetrating radar (GPR) data are simulated using the scalar wave equation in which the velocity is controlled by the dielectric permittivity distribution. The propagation velocity in which the EM pulses travel depends on the dielectric permittivity of the material. The algorithm uses the finite difference technique with operators of second order to solve the time and spatial derivatives and also fourth order to solve the spatial derivatives. The shot gathers in association with time slices and also with snapshots constitutes a powerful tool to predict the response of buried structures. (author). 14 refs., 4 figs

  2. Ground-penetrating radar and electrical resistivity tomography for mapping bedrock topography and fracture zones: a case study in Viru-Nigula, NE Estonia

    Directory of Open Access Journals (Sweden)

    Ivo Sibul

    2017-06-01

    Full Text Available The Geological Base Map (GBM, presenting an elongated buried valley running beneath the Varudi bog, triggered the geophysical studies near Viru-Nigula borough in northeastern Estonia. After the Geological Survey of Estonia had compiled the GBM map set, the course and extent of the valley still remained indistinct. Principally the morphology of the Varudi valley had been determined just by one borehole characterizing the 30 m thick Quaternary succession within the valley. The thickness of Quaternary sediments is, however, just a few metres in adjacent boreholes. We used ground-penetrating radar and electrical resistivity tomography (ERT for acquiring extra knowledge about the extent and morphology of the Varudi structure. Ground-penetrating radar enabled us to specify the thickness and composition of Quaternary deposits, and to recognize dislocations of the bedrock blocks. As the radar images provided information on the topmost ~4 m only, ERT (Wenner and Wenner–Schlumberger arrays was applied to define deeper, down to 40 m, electrical resistivity anomalies. The ERT studies revealed two fracture zones where regular Ordovician carbonate beds have been crushed and replaced by Quaternary sediments. The Varudi valley coincides with the southern zone. Both fracture zones probably acted as groundwater flow channels and sediment pathways in the Late Pleistocene, and hence supported the creation of the Varudi bog.

  3. A closed-loop automatic control system for high-intensity acoustic test systems.

    Science.gov (United States)

    Slusser, R. A.

    1973-01-01

    Sound at sound pressure levels in the range from 130 to 160 dB is used in the investigation. Random noise is passed through a series of parallel filters, generally 1/3-octave wide. A basic automatic system is investigated because of preadjustment inaccuracies and high costs found in a study of a typical manually controlled acoustic testing system. The unit described has been successfully used in automatic acoustic tests in connection with the spacecraft tests for the Mariner 1971 program.

  4. The lost church of Montemurro (Basilicata, Italy): Ground Penetrating Radar and Electrical Resistivity Tomography for detecting its buried remains in S. Maria Square.

    Science.gov (United States)

    Bavusi, Massimo; Giocoli, Alessandro; de Martino, Gregory; Loperte, Antonio; Lapenna, Vincenzo

    2010-05-01

    Montemurro is a little centre town located in the Agri Valley (Basilicata Region, Italy) which was affected by two catastrophic events: in the 1842 a very large landslide has damaged great part of the centre and in the 1857 the town was destroyed completely by the "Great Neapolitan Earthquake" (Mallet, 1862), a seismic event having epicenter in the Agri Valley (Cello et al., 2003; Bavusi et al., 2004). Signs of those tragic events can be still found in the fabric of the city. One of these is certainly S. Maria square, a place suspected to house a church before the disastrous events of 1842. This suspicion is supported by a series of evidences: a historical drawing, dating back to before 1842, shows a church in position compatible with the location of the square; in aerial view S. Maria square appears as tear in the fabric of the city; the tales of the erderlies of Montemurro speak about an ancient missing church in the town. Then, in the attempt to resolve the doubt about the presence of the church, a geophysical survey was planned in S. Maria Square with the aim to detect some buried masonry structures related to the church. In this work we selected two active techniques such as the Ground Penetrating Radar (GPR) and the Electrical Resistivity Tomography (ERT). Sixty parallel GPR profiles 0.5 m spaced were gathered in S. Maria Square and in a contiguous street by using a GSSI SIR3000 system with a central frequency antenna of 200 MHz. Processed radargrams showed numerous reflectors and heterogeneities in the subsoil related to manmade objects. Then, a laborious data processing (Nuzzo et al., 2002) allowed to obtain several time-slices showing noticeable reflections compatible with masonry structures. Moreover, two ERT profiles were carried out by using an IRIS Syscal R2 system equipped with a multielectrode cable. The first ERT profile 86 m long and having 44 electrodes 2 m spaced allowed to investigate up to 9 m of depth. The second, overlapped on the previous

  5. Development of a MEMS acoustic emission sensor system

    Science.gov (United States)

    Greve, David W.; Oppenheim, Irving J.; Wu, Wei; Wright, Amelia P.

    2007-04-01

    An improved multi-channel MEMS chip for acoustic emission sensing has been designed and fabricated in 2006 to create a device that is smaller in size, superior in sensitivity, and more practical to manufacture than earlier designs. The device, fabricated in the MUMPS process, contains four resonant-type capacitive transducers in the frequency range between 100 kHz and 500 kHz on a chip with an area smaller than 2.5 sq. mm. The completed device, with its circuit board, electronics, housing, and connectors, possesses a square footprint measuring 25 mm x 25 mm. The small footprint is an important attribute for an acoustic emission sensor, because multiple sensors must typically be arrayed around a crack location. Superior sensitivity was achieved by a combination of four factors: the reduction of squeeze film damping, a resonant frequency approximating a rigid body mode rather than a bending mode, a ceramic package providing direct acoustic coupling to the structural medium, and high-gain amplifiers implemented on a small circuit board. Manufacture of the system is more practical because of higher yield (lower unit costs) in the MUMPS fabrication task and because of a printed circuit board matching the pin array of the MEMS chip ceramic package for easy assembly and compactness. The transducers on the MEMS chip incorporate two major mechanical improvements, one involving squeeze film damping and one involving the separation of resonance modes. For equal proportions of hole area to plate area, a triangular layout of etch holes reduces squeeze film damping as compared to the conventional square layout. The effect is modeled analytically, and is verified experimentally by characterization experiments on the new transducers. Structurally, the transducers are plates with spring supports; a rigid plate would be the most sensitive transducer, and bending decreases the sensitivity. In this chip, the structure was designed for an order-of-magnitude separation between the first

  6. Advances and numerical simulation of airborne ground penetrating radar%机载探地雷达的进展以及数值模拟

    Institute of Scientific and Technical Information of China (English)

    刘四新; 冯彦谦; 傅磊; 王飞; 王元新

    2012-01-01

    Airborne ground penetrating radar (GPR) is a potential tool for near-surface detection in dangerous and regional areass it can be used for environmental and ecological evaluation, or military purpose. This technique is slow due to kinds of reasons. To promote the development of the technique, this paper introduces the advance of the technique worldly, and simulates the airborne GPR detection for typical near-surface models, the simulated data are imaged with special migration method. It is shown that current airborne GPR can be classified into three types. The first suspend conventional commercial GPR antennas and control unit under a helicopter. The second type is fabricated for airborne survey, and has special hardware and system. The third type is synthetic aperture radar with penetrating capability. It is shown that the targets under both the flat ground surface and the rough surface can be imaged clearly. It is concluded that air-borne GPR is a potential tool for subsurface measurement will receive more attention in the future.%机载探地雷达可能解决危险环境或广域条件下的近地表探测问题,用于解决环境、生态或军事方面的问题.然而由于种种原因,该技术的发展却显得比较慢.为了推进该技术的发展,本文介绍了目前世界范围内机载探地雷达的进展,并利用时间域有限差分法对一些典型模型进行数值模拟,并用特定的偏移成像方法对模拟结果进行成像.目前存在的机载探地雷达主要有三种类型:第一种为将常规探地雷达天线悬挂在直升飞机上,第二种为针对机载探地雷达开发的雷达系统,第三种为具有探地能力的合成孔径雷达.数值模拟结果表明,不管是水平地面的情况下,还是起伏界面的情况下,机载探地雷达都能清楚探测一定深度范围内的地下目标.可见,机载探地雷达是存满希望的一种方法.

  7. System and method for characterizing voiced excitations of speech and acoustic signals, removing acoustic noise from speech, and synthesizing speech

    Energy Technology Data Exchange (ETDEWEB)

    Burnett, Greg C.; Holzrichter, John F.; Ng, Lawrence C.

    2006-02-14

    The present invention is a system and method for characterizing human (or animate) speech voiced excitation functions and acoustic signals, for removing unwanted acoustic noise which often occurs when a speaker uses a microphone in common environments, and for synthesizing personalized or modified human (or other animate) speech upon command from a controller. A low power EM sensor is used to detect the motions of windpipe tissues in the glottal region of the human speech system before, during, and after voiced speech is produced by a user. From these tissue motion measurements, a voiced excitation function can be derived. Further, the excitation function provides speech production information to enhance noise removal from human speech and it enables accurate transfer functions of speech to be obtained. Previously stored excitation and transfer functions can be used for synthesizing personalized or modified human speech. Configurations of EM sensor and acoustic microphone systems are described to enhance noise cancellation and to enable multiple articulator measurements.

  8. System and method for characterizing voiced excitations of speech and acoustic signals, removing acoustic noise from speech, and synthesizing speech

    Energy Technology Data Exchange (ETDEWEB)

    Burnett, Greg C. (Livermore, CA); Holzrichter, John F. (Berkeley, CA); Ng, Lawrence C. (Danville, CA)

    2006-08-08

    The present invention is a system and method for characterizing human (or animate) speech voiced excitation functions and acoustic signals, for removing unwanted acoustic noise which often occurs when a speaker uses a microphone in common environments, and for synthesizing personalized or modified human (or other animate) speech upon command from a controller. A low power EM sensor is used to detect the motions of windpipe tissues in the glottal region of the human speech system before, during, and after voiced speech is produced by a user. From these tissue motion measurements, a voiced excitation function can be derived. Further, the excitation function provides speech production information to enhance noise removal from human speech and it enables accurate transfer functions of speech to be obtained. Previously stored excitation and transfer functions can be used for synthesizing personalized or modified human speech. Configurations of EM sensor and acoustic microphone systems are described to enhance noise cancellation and to enable multiple articulator measurements.

  9. System and method for characterizing voiced excitations of speech and acoustic signals, removing acoustic noise from speech, and synthesizing speech

    Energy Technology Data Exchange (ETDEWEB)

    Burnett, Greg C.; Holzrichter, John F.; Ng, Lawrence C.

    2004-03-23

    The present invention is a system and method for characterizing human (or animate) speech voiced excitation functions and acoustic signals, for removing unwanted acoustic noise which often occurs when a speaker uses a microphone in common environments, and for synthesizing personalized or modified human (or other animate) speech upon command from a controller. A low power EM sensor is used to detect the motions of windpipe tissues in the glottal region of the human speech system before, during, and after voiced speech is produced by a user. From these tissue motion measurements, a voiced excitation function can be derived. Further, the excitation function provides speech production information to enhance noise removal from human speech and it enables accurate transfer functions of speech to be obtained. Previously stored excitation and transfer functions can be used for synthesizing personalized or modified human speech. Configurations of EM sensor and acoustic microphone systems are described to enhance noise cancellation and to enable multiple articulator measurements.

  10. System And Method For Characterizing Voiced Excitations Of Speech And Acoustic Signals, Removing Acoustic Noise From Speech, And Synthesizi

    Energy Technology Data Exchange (ETDEWEB)

    Burnett, Greg C. (Livermore, CA); Holzrichter, John F. (Berkeley, CA); Ng, Lawrence C. (Danville, CA)

    2006-04-25

    The present invention is a system and method for characterizing human (or animate) speech voiced excitation functions and acoustic signals, for removing unwanted acoustic noise which often occurs when a speaker uses a microphone in common environments, and for synthesizing personalized or modified human (or other animate) speech upon command from a controller. A low power EM sensor is used to detect the motions of windpipe tissues in the glottal region of the human speech system before, during, and after voiced speech is produced by a user. From these tissue motion measurements, a voiced excitation function can be derived. Further, the excitation function provides speech production information to enhance noise removal from human speech and it enables accurate transfer functions of speech to be obtained. Previously stored excitation and transfer functions can be used for synthesizing personalized or modified human speech. Configurations of EM sensor and acoustic microphone systems are described to enhance noise cancellation and to enable multiple articulator measurements.

  11. Diagnostic System of Wireless Acoustic Emission Signal Transfer for Monitoring Oil-and-Gas Facilities

    Directory of Open Access Journals (Sweden)

    Skalsky, V.R.

    2016-01-01

    Full Text Available The structure of diagnostic 8-channel system for wireless transfer of acoustic emission information during monitoring the objects of long operation is revealed. The results of the development of algorithmic software for hardware system and personal computer, which performs system control and post-processing of acoustic emission information. are presented. The basic specifications of the system are described.

  12. [Pärtel Lippus. The acoustic features and perception of the Estonian quantity system] / Stefan Werner

    Index Scriptorium Estoniae

    Werner, Stefan

    2012-01-01

    Arvustus: Pärtel Lippus. The acoustic features and perception of the Estonian quantity system. Tartu : Tartu University Press, 2011. (Dissertationes philologiae estonicae Universitatis Tartuensis ; 29)

  13. [Pärtel Lippus. The acoustic features and perception of the Estonian quantity system] / Stefan Werner

    Index Scriptorium Estoniae

    Werner, Stefan

    2012-01-01

    Arvustus: Pärtel Lippus. The acoustic features and perception of the Estonian quantity system. Tartu : Tartu University Press, 2011. (Dissertationes philologiae estonicae Universitatis Tartuensis ; 29)

  14. Photo acoustic imaging: technology, systems and market trends

    Science.gov (United States)

    Faucheux, Marc; d'Humières, Benoît; Cochard, Jacques

    2017-03-01

    Although the Photo Acoustic effect was observed by Graham Bell in 1880, the first applications (gas analysis) occurred in 1970's using the required energetic light pulses from lasers. During mid 1990's medical imaging research begun to use Photo Acoustic effect and in vivo images were obtained in mid-2000. Since 2009, the number of patent related to Photo Acoustic Imaging (PAI) has dramatically increased. PAI machines for pre-clinical and small animal imaging have been being used in a routine way for several years. Based on its very interesting features (non-ionizing radiation, noninvasive, high depth resolution ratio, scalability, moderate price) and because it is able to deliver not only anatomical, but functional and molecular information, PAI is a very promising clinical imaging modality. It penetrates deeper into tissue than OCT (Optical Coherence Tomography) and provides a higher resolution than ultrasounds. The PAI is one of the most growing imaging modality and some innovative clinical systems are planned to be on market in 2017. Our study analyzes the different approaches such as photoacoustic computed tomography, 3D photoacoustic microscopy, multispectral photoacoustic tomography and endoscopy with the recent and tremendous technological progress over the past decade: advances in image reconstruction algorithms, laser technology, ultrasound detectors and miniaturization. We analyze which medical domains and applications are the most concerned and explain what should be the forthcoming medical system in the near future. We segment the market in four parts: Components and R&D, pre-clinical, analytics, clinical. We analyzed what should be, quantitatively and qualitatively, the PAI medical markets in each segment and its main trends. We point out the market accessibility (patents, regulations, clinical evaluations, clinical acceptance, funding). In conclusion, we explain the main market drivers and challenges to overcome and give a road map for medical

  15. An acoustic imaging system of migration technique used in borehole

    Institute of Scientific and Technical Information of China (English)

    LIN Weijun; WU Nan; SUN Jian; ZHANG Hailan

    2008-01-01

    In order to detect the damage of casing boreholes, an acoustic imaging method with a two-dimensional ultrasonic array was presented. Each element of the array independently emits down ultrasonic waves, the echoes received by all elements are sampled and transmitted to a computer on ground surface, where the dynamic migration method is used to form a 2 or 3-dimensional image of the situation in the borehole. The numerical simulation and experiment are conducted that demonstrate a high imaging accuracy with a small number of elements used in array. Since the delay circuits used in the traditional phased array imaging system is not needed in this system, and all data process could be completed in a ground system,the complexity and the volume of system in borehole may be significantly simplified, which is critical to the borehole instrument.

  16. Reading of Ground-Penetrating Radar (GPR Images of Prehistoric Flint Mine; Case Study from Krzemionki Opatowskie Archaeological Site In Central Poland

    Directory of Open Access Journals (Sweden)

    Welc Fabian

    2016-12-01

    Full Text Available Geophysical surveys conducted in order to map tunnels and vertical shafts at the Neolithic chert mining field Krzemionki used a ground-penetrating radar(GPR to test hypotheses regarding orientation, depth and subsurface complexity of these voids.Using two-dimensional reflection profiles the vertical shafts, now mostly filled with lithic debris, were easily visible. Amplitude mapping visualized debris at shaft margins as well as a collapsed material inside the voids. Some shallower horizontal tunnels were also visible as sub-horizontal planar reflections generated from both ceiling and floors of these void spaces. Extension of these interpretations to un-mapped areas of the ancient mining district and complexity of these prehistoric mining features could be examined to determine excavation intensity and exploitation techniques used during the Neolithic.

  17. Accuracy assessment of NOGGIN Plus and MALÅ RAMAC X3M single channel ground penetrating RADAR (GPR) for underground utility mapping

    Science.gov (United States)

    Sazali Hashim, Mas; Nizam Saip, Saiful; Hani, Nurfauziah; Pradhan, Biswajeet; Abdullahi, Saleh

    2016-06-01

    Ground Penetrating Radar (GPR) becomes a popular device in investigation of the underground utilities in recent years. GPR analyses the type and position of utility objects. However, the performance accuracy of GPR models is an important issue that should be considered. This study conducts the accuracy analysis between two models of single channel GPR; NOGGIN PLUS and MALÅ RAMAC X3M, by focusing on the basic principles of single channel GPR, accuracy analysis and calibration methods implemented on GPR. The survey work has been performed to identify the most accurate instrument to detect underground utility objects. In addition, data analysis was carried out to compare between two models of single channel GPR. This study provides proper guidelines and assists surveyors to select the suitable instruments regarding on applications especially on utility mapping in terms of accuracy.

  18. Design And Simulation Of An Acoustic Echo Cancellation System For Hand-Free Telecommunication

    Directory of Open Access Journals (Sweden)

    Ein Gyin Pwint

    2015-06-01

    Full Text Available Abstract Acoustic echo cancellation is a common occurrence in todays telecommunication systems. The signal interference caused by acoustic echo is distracting to users and causes a reduction in the quality of the communication. This paper is implementing the overall system of acoustic echo cancellation system using LMS and NLMS algorithms for adaptive filter normalized cross correlation NCC algorithm double talk detector. The result of echo return loss enhancement ERLE and mean squared error MSE which show that how much the amount of echo signal cancelled and the amount of residual error signal for cancelling acoustic echo cancellation on a PC with the help of the MATLAB software.

  19. Microcontroller-based underwater acoustic ECG telemetry system.

    Science.gov (United States)

    Istepanian, R S; Woodward, B

    1997-06-01

    This paper presents a microcontroller-based underwater acoustic telemetry system for digital transmission of the electrocardiogram (ECG). The system is designed for the real time, through-water transmission of data representing any parameter, and it was used initially for transmitting in multiplexed format the heart rate, breathing rate and depth of a diver using self-contained underwater breathing apparatus (SCUBA). Here, it is used to monitor cardiovascular reflexes during diving and swimming. The programmable capability of the system provides an effective solution to the problem of transmitting data in the presence of multipath interference. An important feature of the paper is a comparative performance analysis of two encoding methods, Pulse Code Modulation (PCM) and Pulse Position Modulation (PPM).

  20. Inference of Fractured Rock Transport Properties by Joint Inversion of Push-Pull and Single-Hole Ground Penetrating Radar Data

    Science.gov (United States)

    Shakas, A.; Linde, N.; Bour, O.; Le Borgne, T.

    2015-12-01

    Flow and transport characterization of fractured rock formations is very challenging and important for a multitude of applications that include groundwater extraction, nuclear waste storage and geothermal energy production. One popular hydrogeological method to study fractured rock is a push-pull test, in which injection and retrieval of a tracer is made at the same depth interval in a borehole. In theory, push-pull tests are not sensitive to changes in the heterogeneity of the tracer flow path since the retrieval at the injection location minimizes advective effects and makes the test more sensitive to time-dependent transport processes. This assumption is limiting in the presence of a natural hydraulic gradient or if non-neutrally buoyant tracers are used, but these limitations can be reduced by monitoring push-pull tests with ground penetrating radar (GPR). We present a methodology for combined modeling and inversion of a series of push-pull tests that we monitored with the single hole ground penetrating radar (GPR) method. For the GPR modeling we use a newly developed approach to simulate the GPR response in fractured rock. We coupled the GPR model to a flow-and-transport simulator that we use to define the electrical properties of the fracture filling. The combined model can cope with heterogeneous fractures of any orientation, aperture and size and allows for the effect of density driven flow (that is strong during the saline tracer tests). We use the combined simulator to create synthetic datasets for both the time-series of the GPR traces at different locations and the tracer breakthrough curves. Since the combined problem is highly non-linear and the inverse solution is ill-posed, we use stochastic inversion techniques to obtain probabilistic estimates of the parameters of interest (fracture length, orientation and aperture distribution) and assess the use of different measures to compare the simulated and experimental data.

  1. Comparison of spatial frequency domain features for the detection of side attack explosive ballistics in synthetic aperture acoustics

    Science.gov (United States)

    Dowdy, Josh; Anderson, Derek T.; Luke, Robert H.; Ball, John E.; Keller, James M.; Havens, Timothy C.

    2016-05-01

    Explosive hazards in current and former conflict zones are a threat to both military and civilian personnel. As a result, much effort has been dedicated to identifying automated algorithms and systems to detect these threats. However, robust detection is complicated due to factors like the varied composition and anatomy of such hazards. In order to solve this challenge, a number of platforms (vehicle-based, handheld, etc.) and sensors (infrared, ground penetrating radar, acoustics, etc.) are being explored. In this article, we investigate the detection of side attack explosive ballistics via a vehicle-mounted acoustic sensor. In particular, we explore three acoustic features, one in the time domain and two on synthetic aperture acoustic (SAA) beamformed imagery. The idea is to exploit the varying acoustic frequency profile of a target due to its unique geometry and material composition with respect to different viewing angles. The first two features build their angle specific frequency information using a highly constrained subset of the signal data and the last feature builds its frequency profile using all available signal data for a given region of interest (centered on the candidate target location). Performance is assessed in the context of receiver operating characteristic (ROC) curves on cross-validation experiments for data collected at a U.S. Army test site on different days with multiple target types and clutter. Our preliminary results are encouraging and indicate that the top performing feature is the unrolled two dimensional discrete Fourier transform (DFT) of SAA beamformed imagery.

  2. A realization of sound focused personal audio system using acoustic contrast control.

    Science.gov (United States)

    Chang, Ji-Ho; Lee, Chan-Hui; Park, Jin-Young; Kim, Yang-Hann

    2009-04-01

    A personal audio system that does not use earphone or any wire would have great interest and potential impact on the audio industries. In this study, a line array speaker system is used to localize sound in the listening zone. The contrast control [Choi, J.-W. and Kim, Y.-H. (2002). J. Acoust. Soc. Am. 111, 1695-1700] is applied, which is a method to make acoustically bright zone around the user and acoustically dark zone in other regions by maximizing the ratio of acoustic potential energy density between the bright and the dark zone. This ratio is regarded as acoustic contrast, analogous with what is used for optical devices. For the evaluation of the performance of acoustic contrast control, experiments are performed and the results are compared with those of uncontrolled case and time reversal array.

  3. Detection of impulsive sources from an aerostat-based acoustic array data collection system

    Science.gov (United States)

    Prather, Wayne E.; Clark, Robert C.; Strickland, Joshua; Frazier, Wm. Garth; Singleton, Jere

    2009-05-01

    An aerostat based acoustic array data collection system was deployed at the NATO TG-53 "Acoustic Detection of Weapon Firing" Joint Field Experiment conducted in Bourges, France during the final two weeks of June 2008. A variety of impulsive sources including mortar, artillery, gunfire, RPG, and explosive devices were fired during the test. Results from the aerostat acoustic array will be presented against the entire range of sources.

  4. Design and testing of Ground Penetrating Radar equipment dedicated for civil engineering applications: ongoing activities in Working Group 1 of COST Action TU1208

    Science.gov (United States)

    Pajewski, Lara; Manacorda, Guido; Persico, Raffaele

    2015-04-01

    This work aims at presenting the ongoing research activities carried out in Working Group 1 'Novel GPR instrumentation' of the COST (European COoperation in Science and Technology) Action TU1208 'Civil Engineering Applications of Ground Penetrating Radar' (www.GPRadar.eu). The principal goal of the COST Action TU1208 is to exchange and increase scientific-technical knowledge and experience of GPR techniques in civil engineering, simultaneously promoting throughout Europe the effective use of this safe and non-destructive technique in the monitoring of infrastructures and structures. Working Group 1 (WG1) of the Action focuses on the development of innovative GPR equipment dedicated for civil engineering applications. It includes three Projects. Project 1.1 is focused on the 'Design, realisation and optimisation of innovative GPR equipment for the monitoring of critical transport infrastructures and buildings, and for the sensing of underground utilities and voids.' Project 1.2 is concerned with the 'Development and definition of advanced testing, calibration and stability procedures and protocols, for GPR equipment.' Project 1.3 deals with the 'Design, modelling and optimisation of GPR antennas.' During the first year of the Action, WG1 Members coordinated between themselves to address the state of the art and open problems in the scientific fields identified by the above-mentioned Projects [1, 2]. In carrying our this work, the WG1 strongly benefited from the participation of IDS Ingegneria dei Sistemi, one of the biggest GPR manufacturers, as well as from the contribution of external experts as David J. Daniels and Erica Utsi, sharing with the Action Members their wide experience on GPR technology and methodology (First General Meeting, July 2013). The synergy with WG2 and WG4 of the Action was useful for a deep understanding of the problems, merits and limits of available GPR equipment, as well as to discuss how to quantify the reliability of GPR results. An

  5. Acoustic Filtration, Fractionation, and Mixing in Microfluidic Systems

    Energy Technology Data Exchange (ETDEWEB)

    Wang, A; Fisher, K

    2002-02-04

    This project is concerned with the research and development of a technique to manipulate small particles using acoustic energy coupled into a fluid filled plastic or glass sample chamber. These resulting miniaturized systems combine high functionality with an inexpensive, disposable sample chamber. Our approach to this problem is based on a combination of sophisticated modeling tools in conjunction with laboratory experiments. The design methodology is summarized in Figure 1. The process begins by investigating a wide range of device parameters using a one-dimensional analytical approximation. The results of these initial parameter studies are incorporated into a sophisticated three-dimensional multi-physics finite element code. From these simulations the optimized designs are prototyped and experimentally tested. The results of the experimental observations are then used to improve analytical approximations and the process is repeated as necessary.

  6. Acoustic Emissions (AE) Electrical Systems' Health Monitoring Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Acoustic Emissions (AE) are associated with physical events, such as thermal activity, dielectric breakdown, discharge inception, as well as crack nucleation and...

  7. Development of radio acoustic sounding system (RASS) with Gadanki MST radar – first results

    OpenAIRE

    T. V. Chandrasekhar Sarma; Narayana Rao, D.; Furumoto, J.; Tsuda, T.

    2008-01-01

    A high-power acoustic exciter was designed and developed for the Gadanki MST Radar to facilitate observations in the Radio Acoustic Sounding System (RASS) mode. Sweep range of acoustic signal frequencies was set to 94–125 Hz so as to satisfy Bragg matching condition for temperature range of −90°–40°C between surface and the tropopause (about 17 km). Raytracing of acoustic wave propagation was used to predict the antenna beam directions along which optimum RASS echoes could be ob...

  8. Simulation and Development of Improved Acoustic Damping Systems for Broadband Noise Attention in Payload Fairings

    Science.gov (United States)

    Eaton, Nick

    2012-07-01

    RUAG Space specialise in payload fairings which must achieve set requirements for structural, jettisoning, mass and other functions and provide a safe acoustic environment for the satellite during launch. Protecting the satellite from acoustic induced vibration is achieved by a defined Noise Reduction spectrum performance, typically covering the 31 - 2000 Hz octave band frequency range. RUAG recently undertook an R&D program to optimise acoustic performance by i) understanding of the sound transmission mechanisms ii) modelling of fairing noise reduction iii) new acoustic treatments iv) reduction of sound leakage through vents v) combination of these elements in a possible future fairing design to assess the overall effectiveness at fairing system level.

  9. Seismic wave detection system based on fully distributed acoustic sensing

    Science.gov (United States)

    Jiang, Yue; Xu, Tuanwei; Feng, Shengwen; Huang, Jianfen; Yang, Yang; Guo, Gaoran; Li, Fang

    2016-11-01

    This paper presents a seismic wave detection system based on fully distributed acoustic sensing. Combined with Φ- OTDR and PGC demodulation technology, the system can detect and acquire seismic wave in real time. The system has a frequency response of 3.05 dB from 5 Hz to 1 kHz, whose sampling interval of each channel of 1 meter on total sensing distance up to 10 km. By comparing with the geophone in laboratory, the data show that in the time domain and frequency domain, two waveforms coincide consistently, and the correlation coefficient could be larger than 0.98. Through the analysis of the data of the array experiment and the oil well experiment, DAS system shows a consistent time domain and frequency domain response and a clearer trail of seismic wave signal as well as a higher signal-noise rate which indicate that the system we proposed is expected to become the next generation of seismic exploration equipment.

  10. Resonant acoustic transducer system for a well drilling string

    Science.gov (United States)

    Kent, William H.; Mitchell, Peter G.

    1981-01-01

    For use in transmitting acoustic waves propagated along a well drilling string, a piezoelectric transducer is provided operating in the relatively low loss acoustic propagation range of the well drilling string. The efficiently coupled transmitting transducer incorporates a mass-spring-piezoelectric transmitter combination permitting resonant operation in the desired low frequency range.

  11. Passive Autonomous Acoustic Monitoring of Marine Mammals: System Development Using Seaglider (Trademark)

    Science.gov (United States)

    2015-01-30

    DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Passive Autonomous Acoustic Monitoring of Marine Mammals...System Development Using Seaglider Final Report 30 January 2015 Neil M. Bogue Applied Physics Laboratory University of Washington Box ...award as part of the Office of Naval Research’s (ONR) Passive Autonomous Acoustic Monitoring (PAAM) program. The initial long-term goals of the PAAM

  12. Acoustic fMRI noise : Linear time-invariant system model

    NARCIS (Netherlands)

    Sierra, Carlos V. Rizzo; Versluis, Maarten J.; Hoogduin, Johannes M.; Duifhuis, Hendrikus (Diek)

    2008-01-01

    Functional magnetic resonance imaging (fMRI) enables sites of brain activation to be localized in human subjects. For auditory system studies, however, the acoustic noise generated by the scanner tends to interfere with the assessments of this activation. Understanding and modeling fMRI acoustic noi

  13. High-resolution mapping of soil moisture at the field scale using ground-penetrating radar for improving remote sensing data products

    Science.gov (United States)

    Lambot, Sébastien; Mahmoudzadeh, Mohammad Reza; Phuong Tran, Anh; Nottebaere, Martijn; Leonard, Aline; Defourny, Pierre; Neyt, Xavier

    2014-05-01

    Characterizing the spatiotemporal distribution of soil moisture at various scales is essential in agricultural, hydrological, meteorological, and climatological research and applications. Soil moisture determines the boundary condition between the soil and the atmosphere and governs key processes of the hydrological cycle such as infiltration, runoff, root water uptake, evaporation, as well as energy exchanges between the Earth's surface and the atmosphere. In that respect, ground-penetrating radar (GPR) is of particular interest for field-scale soil moisture mapping as soil moisture is highly correlated to its permittivity, which controls radar wave propagation in the soil. Yet, accurate determination of the electrical properties of a medium using GPR requires full-wave inverse modeling, which has remained a major challenge in applied geophysics for many years. We present a new near-field radar modeling approach for wave propagation in layered media. Radar antennas are modeled using an equivalent set of infinitesimal electric dipoles and characteristic, frequency-dependent, global reflection and transmission coefficients. These coefficients determine wave propagation between the radar reference plane, point sources, and field points. The interactions between the antenna and the soil are inherently accounted for. The fields are calculated using three-dimensional Green's functions. We validated the model using both time and frequency domain radars. The radars were mounted on a quad and controlled by a computer for real-time radar and dGPS data acquisition. Several fields were investigated and time-lapse measurements were performed on some of them to analyze temporal stability in soil moisture patterns and the repeatability of the measurements. The results were compared to ground-truths. The proposed technique is presently being applied to improve space-borne remote sensing data products for soil moisture by providing high-resolution observational information that

  14. Using ground penetrating radar to investigate the water table depth in weathered granites : Sardon case study, Spain

    NARCIS (Netherlands)

    Mahmoudzadeh, M.R.; Frances, A.P.; Lubczynski, M.; Lambot, S.

    2012-01-01

    Precise and non-invasive measurement of groundwater depth is essential to support management of groundwater resources. In that respect, GPR is a promising tool for high resolution, large scale characterization and monitoring of hydrological systems. We applied GPR in a semi-arid catchment (Sardon, S

  15. GEOMORPHIC CONTROLS ON MEADOW ECOSYSTEMS – INSIGHTS INTO LOCAL PROCESSES USING NEAR-SURFACE SEISMIC TECHNIQUES AND GROUND PENETRATING RADAR

    Science.gov (United States)

    Geomorphic controls on riparian meadows in the Central Great Basin of Nevada are an important aspect in determining the formation of and planning the management of these systems. The current hypothesis is that both alluvial fan sediment and faulted bedrock steps interact to cont...

  16. GEOMORPHIC CONTROLS ON MEADOW ECOSYSTEMS – INSIGHTS INTO LOCAL PROCESSES USING NEAR-SURFACE SEISMIC TECHNIQUES AND GROUND PENETRATING RADAR

    Science.gov (United States)

    Geomorphic controls on riparian meadows in the Central Great Basin of Nevada are an important aspect in determining the formation of and planning the management of these systems. The current hypothesis is that both alluvial fan sediment and faulted bedrock steps interact to cont...

  17. Improving acoustic streaming effects in fluidic systems by matching SU-8 and polydimethylsiloxane layers.

    Science.gov (United States)

    Catarino, S O; Minas, G; Miranda, J M

    2016-07-01

    This paper reports the use of acoustic waves for promoting and improving streaming in tridimensional polymethylmethacrylate (PMMA) cuvettes of 15mm width×14mm height×2.5mm thickness. The acoustic waves are generated by a 28μm thick poly(vinylidene fluoride) - PVDF - piezoelectric transducer in its β phase, actuated at its resonance frequency: 40MHz. The acoustic transmission properties of two materials - SU-8 and polydimethylsiloxane (PDMS) - were numerically compared. It was concluded that PDMS inhibits, while SU-8 allows, the transmission of the acoustic waves to the propagation medium. Therefore, by simulating the acoustic transmission properties of different materials, it is possible to preview the acoustic behavior in the fluidic system, which allows the optimization of the best layout design, saving costs and time. This work also presents a comparison between numerical and experimental results of acoustic streaming obtained with that β-PVDF transducer in the movement and in the formation of fluid recirculation in tridimensional closed domains. Differences between the numerical and experimental results are credited to the high sensitivity of acoustic streaming to the experimental conditions and to limitations of the numerical method. The reported study contributes for the improvement of simulation models that can be extremely useful for predicting the acoustic effects of new materials in fluidic devices, as well as for optimizing the transducers and matching layers positioning in a fluidic structure.

  18. Integrated Resistivity and Ground Penetrating Radar Observations of Underground Seepage of Hot Water at Blawan-Ijen Geothermal Field

    OpenAIRE

    Sukir Maryanto; Ika Karlina Laila Nur Suciningtyas; Cinantya Nirmala Dewi; Arief Rachmansyah

    2016-01-01

    Geothermal resource investigation was accomplished for Blawan-Ijen geothermal system. Blawan geothermal field which located in the northern part of Ijen caldera presents hydrothermal activity related with Pedati fault and local graben. There were about 21 hot springs manifestations in Blawan-Ijen area with calculated temperature about 50°C. We have performed several geophysical studies of underground seepage of hot water characterization. The geoelectric resistivity and GPR methods are used i...

  19. The integrated satellite-acoustic telemetry (iSAT) system for tracking marine megafauna

    KAUST Repository

    De La Torre, Pedro R.

    2012-10-06

    This document describes the integrated satellite-acoustic telemetry (iSAT) system: an autonomous modular system for tracking the movements of large pelagic fish using acoustic telemetry and satellite communications. The sensor platform is described along with the propulsion and navigation systems. An application for tracking the whale shark (Rhincodon typus) in the Red Sea is included along with a discussion of the technical difficulties that such a system faces.

  20. Collection, processing, and interpretation of ground-penetrating radar data to determine sediment thickness at selected locations in Deep Creek Lake, Garrett County, Maryland, 2007

    Science.gov (United States)

    Banks, William S.L.; Johnson, Carole D.

    2011-01-01

    The U.S. Geological Survey collected geophysical data in Deep Creek Lake in Garrett County, Maryland, between September 17 through October 4, 2007 to assist the Maryland Department of Natural Resources to better manage resources of the Lake. The objectives of the geophysical surveys were to provide estimates of sediment thickness in shallow areas around the Lake and to test the usefulness of three geophysical methods in this setting. Ground-penetrating radar (GPR), continuous seismic-reflection profiling (CSP), and continuous resistivity profiling (CRP) were attempted. Nearly 90 miles of GPR radar data and over 70 miles of CSP data were collected throughout the study area. During field deployment and testing, CRP was determined not to be practical and was not used on a large scale. Sediment accumulation generally could be observed in the radar profiles in the shallow coves. In some seismic profiles, a thin layer of sediment could be observed at the water bottom. The radar profiles appeared to be better than the seismic profiles for the determination of sediment thickness. Although only selected data profiles were processed, all data were archived for future interpretation.

  1. High Resolution ground penetrating radar (GPR) measurements at the laboratory scale to model porosity and permeability in the Miami Limestone in South Florida.

    Science.gov (United States)

    Mount, G. J.; Comas, X.

    2015-12-01

    Subsurface water flow within the Biscayne aquifer is controlled by the heterogeneous distribution of porosity and permeability in the karst Miami Limestone and the presence of numerous dissolution and mega-porous features. The dissolution features and other high porosity areas can create preferential flow paths and direct recharge to the aquifer, which may not be accurately conceptualized in groundwater flow models. As hydrologic conditions are undergoing restoration in the Everglades, understanding the distribution of these high porosity areas within the subsurface would create a better understanding of subsurface flow. This research utilizes ground penetrating radar to estimate the spatial variability of porosity and dielectric permittivity of the Miami Limestone at centimeter scale resolution at the laboratory scale. High frequency GPR antennas were used to measure changes in electromagnetic wave velocity through limestone samples under varying volumetric water contents. The Complex Refractive Index Model (CRIM) was then applied in order to estimate porosity and dielectric permittivity of the solid phase of the limestone. Porosity estimates ranged from 45.2-66.0% from the CRIM model and correspond well with estimates of porosity from analytical and digital image techniques. Dielectric permittivity values of the limestone solid phase ranged from 7.0 and 13.0, which are similar to values in the literature. This research demonstrates the ability of GPR to identify the cm scale spatial variability of aquifer properties that influence subsurface water flow which could have implications for groundwater flow models in the Biscayne and potentially other shallow karst aquifers.

  2. Information-based sensor management for the intelligent tasking of ground penetrating radar and electromagnetic induction sensors in landmine detection pre-screening

    Science.gov (United States)

    Kolba, Mark P.; Collins, Leslie M.

    2010-04-01

    Previous work has introduced a framework for information-based sensor management that is capable of tasking multiple sensors searching for targets among a set of discrete objects or in a cell grid. However, in many real-world scenarios-- such as detecting landmines along a lane or road--an unknown number of targets are present in a continuous spatial region of interest. Consequently, this paper introduces a grid-free sensor management approach that allows multiple sensors to be managed in a sequential search for targets in a grid-free spatial region. Simple yet expressive Gaussian target models are introduced to model the spatial target responses that are observed by the sensors. The sensor manager is then formulated using a Bayesian approach, and sensors are directed to make new observations that maximize the expected information gain between the posterior density on the target parameters after a new observation and the current posterior target parameter density. The grid-free sensor manager is applied to a set of real landmine detection data collected with ground penetrating radar (GPR) and electromagnetic induction (EMI) sensors at a U.S. government test site. Results are presented that compare the performance of the sensor manager with the performance of an unmanaged joint pre-screener that fuses individual GPR and EMI pre-screeners. The sensor manager is demonstrated to provide improved detection performance while requiring substantially fewer sensor observations than are made with the unmanaged joint pre-screening approach.

  3. 地质雷达在混凝土完整性检测中的应用%APPLICATION OF GROUND PENETRATING RADAR IN INTEGRITY DETECTION FOR CONCRETE

    Institute of Scientific and Technical Information of China (English)

    陈月顺; 刘莉

    2011-01-01

    As a high-tech non-destructive testing technology, the ground penetrating radar has been used to detect emerging underground and concrete defect over the last decade, which be used simply and the stability results could be received. In this paper,the Laure SIR-20 radar has been used to detect the integrity of a concrete rail beam,at same time the detect results have been compares the a intact beam,there be a good agreement between them, so the beam concrete integrity is good.%探地雷达作为近10几年来新兴起来的进行地下探测和混凝土无损检测的一种高新技术,具有操作简单,结果稳定的优点。采用劳雷SIR-20型地质雷达,对某轨道梁的混凝土完整性进行检测,同时与完好梁的检测结果进行对比,该梁混凝土完整性较好。

  4. 探地雷达在岩土工程勘察中的应用%Application of Ground Penetrating Radar in Geotechnical Investigation

    Institute of Scientific and Technical Information of China (English)

    李远强; 陈伟

    2011-01-01

    探地雷达是利用超高频脉冲电磁波探测地下介质分布的一种地球物理勘探方法,由于其具有高效率、高分辨率、高准确率等特征,在浅层岩土工程勘察中应用越来越广泛.以国道G110改造工程勘察为例,介绍探地雷达在岩土工程勘察中的应用,对于确定断层的深部展布状况和花岗岩囊状风化界面起到了重要作用,给勘探孔之间地质体的推断解释提供了科学依据.%Ground penetrating radar is a kind of geophysical method which uses very high frequency pulse electromagnetic wave to explore the distribution of underground medium. It is widely used m shallow geotechnical investigation with high efficiency and high resolution Its effective is introduced by the project of G110 Road geotechnical engineering investigation It is exactly to locate the fault and weathered layer. The radar data is scientific evidence in interpret the complicated geotechnical phenomenon

  5. Application of ground penetrating radar for detecting pipeline%瑞典MALA探地雷达在管线探测中的应用

    Institute of Scientific and Technical Information of China (English)

    汤博

    2015-01-01

    Swedish MALA ground penetrating radar (GPR) is applied in this article has carried on the research of under-ground pipeline detection. According to the material of underground pipeline and the surrounding medium and the different choices of different embedding depth, different frequencies of the antenna at the same time set up necessary working param-eters, the different types of underground pipeline detection, and the anomaly characteristics of the engineering examples of typical pipeline are analyzed.%应用瑞典MALA探地雷达进行了地下管线探测的研究。根据地下管线的材质、周围介质及埋设深度的不同选择,不同频率的天线同时设置必要的工作参数,对不同类型的地下管线进行了探测,并对工程实例中典型的管线异常特征进行了分析。

  6. Classification of freshwater ice conditions on the Alaskan Arctic Coastal Plain using ground penetrating radar and TerraSAR-X satellite data

    Science.gov (United States)

    Jones, Benjamin M.; Gusmeroli, Alessio; Arp, Christopher D.; Strozzi, Tazio; Grosse, Guido; Gaglioti, Benjamin V.; Whitman, Matthew S.

    2013-01-01

    Arctic freshwater ecosystems have responded rapidly to climatic changes over the last half century. Lakes and rivers are experiencing a thinning of the seasonal ice cover, which may increase potential over-wintering freshwater habitat, winter water supply for industrial withdrawal, and permafrost degradation. Here, we combined the use of ground penetrating radar (GPR) and high-resolution (HR) spotlight TerraSAR-X (TSX) satellite data (1.25 m resolution) to identify and characterize floating ice and grounded ice conditions in lakes, ponds, beaded stream pools, and an alluvial river channel. Classified ice conditions from the GPR and the TSX data showed excellent agreement: 90.6% for a predominantly floating ice lake, 99.7% for a grounded ice lake, 79.0% for a beaded stream course, and 92.1% for the alluvial river channel. A GIS-based analysis of 890 surface water features larger than 0.01 ha showed that 42% of the total surface water area potentially provided over-wintering habitat during the 2012/2013 winter. Lakes accounted for 89% of this area, whereas the alluvial river channel accounted for 10% and ponds and beaded stream pools each accounted for Arctic with increasing stressors related to climate and land use change.

  7. Determination of ice thickness, subice topography and ice volume at Glacier No. 1 in Tien Shan, China by ground penetrating radar

    Institute of Scientific and Technical Information of China (English)

    孙波; 张鹏; 焦克勤; 邓新生; 温家洪

    2003-01-01

    We describe a radio-echo sounding (RES) survey for the determination of ice thickness, subglacial topography and ice volume of Glacier No. 1, in Tien Shah,China, using ground-penetrating radar (GPR). Radar data were collected with 100-MHz antennas that were spaced at 4 m with a step size of 8 m. The images produced from radar survey clearly show the continuity of bedrock echoes and the undulation features of the bedrock surface. Radar results show that the maximum ice thickness of Glacier No. 1 is 133 m, the thickness of the east branch of Glacier No. 1 averages at 58.77 m while that of the west branch of Glacier No. 1 averages at 44.84 m. Calculation on ice volume indicates that the ice volume of the east branch of Glacier No. 1 is 51.87 × 106 m3 and that of the west branch of Glacier No. 1 is 20.21 × 106 m3. The amplitude of the undulation of the bedrock surface topography revealed by radar profiles is larger than that of the glacier surface topography, indicating that the surface relief does not directly depend on that of the bedrock undulation in Glacier No. 1, in Tien Shan.

  8. An englacial image and water pathways of the Fourcade glacier on King George Island, Antarctic Peninsula, inferred from ground-penetrating radar

    Institute of Scientific and Technical Information of China (English)

    LEE; Joohan; KIM; Ki; Young; HONG; Jong; Kuk; JIN; Young; Keun

    2010-01-01

    The distribution of small fractures and water content of the Fourcade glacier on King George Island, Antarctica, was investigated in November 2006 and December 2007 by two ground-based (470-and 490-m-long profiles) and one helicopter-borne (470-m-long profile) ground-penetrating radar (GPR) surveys using 50-, 100-, and 500-MHz antennas. Radar images in the pre-migrated GPR sections are characterized by a smooth ice surface and irregular bed topography, numerous diffraction hyperbolas in the ice and at the glacier bed, strong scattering noise, and near-surface folded layers. Scattering noise above a mound in the center of the profiles is associated with an area of dense fractures extending down from the ice surface that has relatively low reflection strength. Near the northeast ends of the profiles where few englacial fractures occur, scattering noise may result from the presence of warmer ice. A water-filled conduit and an air-filled cavity are interpreted as the source of two distinct hyperbolas in sub-glacial valleys based on the polarity of the reflections. Through migration velocity analysis on 106 hyperbolas, radar velocities were obtained for the 100-MHz ground-based profile. Using the velocities and Paren’s mixture formula, we calculated the water content of the ice to have been in the range of 0.00–0.09. High water content occurs near the glacier margin, in sub-glacial valleys, and in zones of scattering noise.

  9. Joint application of Geoelectrical Resistivity and Ground Penetrating Radar techniques for the study of hyper-saturated zones. Case study in Egypt

    Science.gov (United States)

    Mesbah, Hany S.; Morsy, Essam A.; Soliman, Mamdouh M.; Kabeel, Khamis

    2017-06-01

    This paper presents the results of the application of the Geoelectrical Resistivity Sounding (GRS) and Ground Penetrating Radar (GPR) for outlining and investigating of surface springing out (flow) of groundwater to the base of an service building site, and determining the reason(s) for the zone of maximum degree of saturation; in addition to provide stratigraphic information for this site. The studied economic building is constructed lower than the ground surface by about 7 m. A Vertical Electrical Sounding (VES) survey was performed at 12 points around the studied building in order to investigate the vertical and lateral extent of the subsurface sequence, three VES's were conducted at each side of the building at discrete distances. And a total of 9 GPR profiles with 100- and 200-MHz antennae were conducted, with the objective of evaluating the depth and the degree of saturation of the subsurface layers. The qualitative and quantitative interpretation of the acquired VES's showed easily the levels of saturations close to and around the studied building. From the interpretation of GPR profiles, it was possible to locate and determine the saturated layers. The radar signals are penetrated and enabled the identification of the subsurface reflectors. The results of GPR and VES showed a good agreement and the integrated interpretations were supported by local geology. Finally, the new constructed geoelectrical resistivity cross-sections (in contoured-form), are easily clarifying the direction of groundwater flow toward the studied building.

  10. The acoustics of aircraft engine-duct systems

    Science.gov (United States)

    Nayfeh, A. H.; Kaiser, J. E.; Telionis, D. P.

    1973-01-01

    Noise generated in aircraft engines is usually suppressed by acoustically treating the engine ducts. The optimization of this treatment requires an understanding of the transmission and attenuation of the acoustic waves. A critical review is presented of the state of the art regarding methods of determining the transmission and attenuation parameters and the effect on these parameters of (1) acoustic properties of liners, (2) the mean velocity, including uniform and shear profiles and nonparallel flow, (3) axial and transverse temperature gradients, (4) slowly and abruptly varying cross sections, and (5) finite-amplitude waves and nonlinear duct liners.

  11. Integrated Resistivity and Ground Penetrating Radar Observations of Underground Seepage of Hot Water at Blawan-Ijen Geothermal Field

    Directory of Open Access Journals (Sweden)

    Sukir Maryanto

    2016-01-01

    Full Text Available Geothermal resource investigation was accomplished for Blawan-Ijen geothermal system. Blawan geothermal field which located in the northern part of Ijen caldera presents hydrothermal activity related with Pedati fault and local graben. There were about 21 hot springs manifestations in Blawan-Ijen area with calculated temperature about 50°C. We have performed several geophysical studies of underground seepage of hot water characterization. The geoelectric resistivity and GPR methods are used in this research because both of them are very sensitive to detect the presence of hot water. These preliminary studies have established reliable methods for hydrothermal survey that can accurately investigate the underground seepage of hot water with shallow depth resolution. We have successfully identified that the underground seepage of hot water in Blawan geothermal field is following the fault direction and river flow which is evidenced by some hot spring along the Banyu Pahit river with resistivity value less than 40 Ωm and medium conductivity.

  12. Analysis, Design, and Evaluation of Acoustic Feedback Cancellation Systems for Hearing Aids

    DEFF Research Database (Denmark)

    Guo, Meng

    2013-01-01

    application that whereas the traditional and stateof- the-art acoustic feedback cancellation systems fail with significant sound distortions and howling as consequences, the new probe noise approach is able to remove feedback artifacts caused by the feedback path change in no more than a few hundred......Acoustic feedback problems occur when the output loudspeaker signal of an audio system is partly returned to the input microphone via an acoustic coupling through the air. This problem often causes significant performance degradations in applications such as public address systems and hearing aids....... In the worst case, the audio system becomes unstable and howling occurs. In this work, first we analyze a general multiple microphone audio processing system, where a cancellation system using adaptive filters is used to cancel the effect of acoustic feedback. We introduce and derive an accurate approximation...

  13. Acoustic Resonance Spectroscopy (ARS) Munition Classification System enhancements. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Vela, O.A.; Huggard, J.C.

    1997-09-18

    Acoustic Resonance Spectroscopy (ARS) is a non-destructive evaluation technology developed at the Los Alamos National Laboratory (LANL). This technology has resulted in three generations of instrumentation, funded by the Defense Special Weapons Agency (DSWA), specifically designed for field identification of chemical weapon (CW) munitions. Each generation of ARS instrumentation was developed with a specific user in mind. The ARS1OO was built for use by the U.N. Inspection Teams going into Iraq immediately after the Persian Gulf War. The ARS200 was built for use in the US-Russia Bilateral Chemical Weapons Treaty (the primary users for this system are the US Onsite Inspection Agency (OSIA) and their Russian counterparts). The ARS300 was built with the requirements of the Organization for the Prohibition of Chemical Weapons (OPCW) in mind. Each successive system is an improved version of the previous system based on learning the weaknesses of each and, coincidentally, on the fact that more time was available to do a requirements analysis and the necessary engineering development. The ARS300 is at a level of development that warrants transferring the technology to a commercial vendor. Since LANL will supply the computer software to the selected vendor, it is possible for LANL to continue to improve the decision algorithms, add features where necessary, and adjust the user interface before the final transfer occurs. This paper describes the current system, ARS system enhancements, and software enhancements. Appendices contain the Operations Manual (software Version 3.01), and two earlier reports on enhancements.

  14. Juvenile Salmon Acoustic Telemetry System Transmitter Downsize Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, Thomas J.; Myjak, Mitchell J.

    2010-04-30

    At the request of the U.S. Army Corps of Engineers, Portland District, researchers from Pacific Northwest National Laboratory investigated the use of an application-specific integrated circuit (ASIC) to reduce the weight and volume of Juvenile Salmon Acoustic Telemetry System (JSATS) transmitters while retaining current functionality. Review of the design of current JSATS transmitters identified components that could be replaced by an ASIC while retaining the function of the current transmitter and offering opportunities to extend function if desired. ASIC design alternatives were identified that could meet transmitter weight and volume targets of 200 mg and 100 mm3. If alternatives to the cylindrical batteries used in current JSATS transmitters can be identified, it could be possible to implant ASIC-based JSATS transmitters by injection rather than surgery. Using criteria for the size of fish suitable for surgical implantation of current JSATS transmitters, it was concluded that fish as small as 70 mm in length could be implanted with an ASIC-based transmitter, particularly if implantation by injection became feasible.

  15. Feature extraction from time domain acoustic signatures of weapons systems fire

    Science.gov (United States)

    Yang, Christine; Goldman, Geoffrey H.

    2014-06-01

    The U.S. Army is interested in developing algorithms to classify weapons systems fire based on their acoustic signatures. To support this effort, an algorithm was developed to extract features from acoustic signatures of weapons systems fire and applied to over 1300 signatures. The algorithm filtered the data using standard techniques then estimated the amplitude and time of the first five peaks and troughs and the location of the zero crossing in the waveform. The results were stored in Excel spreadsheets. The results are being used to develop and test acoustic classifier algorithms.

  16. Development of an Acoustic Levitation Linear Transportation System Based on a Ring-Type Structure.

    Science.gov (United States)

    Thomas, Gilles P L; Andrade, Marco A B; Adamowski, Julio Cezar; Silva, Emilio Carlos Nelli

    2017-05-01

    A linear acoustic levitation transportation system based on a ring-type vibrator is presented. The system is composed by two 21-kHz Langevin transducers connected to a ring-shaped structure formed by two semicircular sections and two flat plates. In this system, a flexural standing wave is generated along the ring structure, producing an acoustic standing wave between the vibrating ring and a plane reflector located at a distance of approximately a half wavelength from the ring. The acoustic standing wave in air has a series of pressure nodes, where small particles can be levitated and transported. The ring-type transportation system was designed and analyzed by using the finite element method. Additionally, a prototype was built and the acoustic levitation and transport of a small polystyrene particle was demonstrated.

  17. PASSIVE WIRELESS MULTI-SENSOR TEMPERATURE AND PRESSURE SENSING SYSTEM USING ACOUSTIC WAVE DEVICES Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal describes the development of passive surface acoustic wave (SAW) sensors and multi-sensor systems for NASA application to remote wireless sensing of...

  18. Passive Wireless Multi-Sensor Temperature and Pressure Sensing System Using Acoustic Wave Devices Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal describes the continued development of passive, orthogonal frequency coded (OFC) surface acoustic wave (SAW) sensors and multi-sensor systems, an...

  19. Acoustic challenges of the A400M for active systems

    Science.gov (United States)

    Breitbach, Harald; Sachau, Delf; Böhme, Sten

    2006-03-01

    In some types of aircraft tonal interior noise with high sound pressure level (up to 110 dB(A)) occurs at low frequencies (f acoustic properties are usually not taken into account. In order to obtain an acceptable interior noise level, and to guarantee both work-safety and comfort in the aircraft interiors, passive methods are commonly used - e.g. adding material with high damping or vibration absorbing qualities. Especially when low frequency noise has to be reduced, adding material results in a lot of unwanted additional weight. In order to avoid this extra weight, the concept of active noise reduction (ANR) and tunable vibration absorber systems (TVA), which focus on the unwanted tonal noise, are a good compromise of treating noise and the amount of additional weight in aircraft design. This paper briefly discusses two different possible methods to reduce the low frequency noise. The noise reduction of tuned vibration absorbers (TVA) mounted on the airframe are nowadays commonly used in propeller driven aircraft and can be predicted by vibroacoustic finite element calculations, which is described in this paper. In order to abide to industrial safety regulations, the noise level inside the semi closed loadmaster area (LMA) must be reduced down to a noise level, which is even 8 dB(A) below the specified cargo hold noise level. The paper describes also the phases of development of an ANR system that could be used to control the sound pressure level inside the LMA. The concept is verified by experimental investigations within a mock up of the LMA.

  20. Evaluation of ground-penetrating radar to detect free-phase hydrocarbons in fractured rocks - Results of numerical modeling and physical experiments

    Science.gov (United States)

    Lane, J.W.; Buursink, M.L.; Haeni, F.P.; Versteeg, R.J.

    2000-01-01

    The suitability of common-offset ground-penetrating radar (GPR) to detect free-phase hydrocarbons in bedrock fractures was evaluated using numerical modeling and physical experiments. The results of one- and two-dimensional numerical modeling at 100 megahertz indicate that GPR reflection amplitudes are relatively insensitive to fracture apertures ranging from 1 to 4 mm. The numerical modeling and physical experiments indicate that differences in the fluids that fill fractures significantly affect the amplitude and the polarity of electromagnetic waves reflected by subhorizontal fractures. Air-filled and hydrocarbon-filled fractures generate low-amplitude reflections that are in-phase with the transmitted pulse. Water-filled fractures create reflections with greater amplitude and opposite polarity than those reflections created by air-filled or hydrocarbon-filled fractures. The results from the numerical modeling and physical experiments demonstrate it is possible to distinguish water-filled fracture reflections from air- or hydrocarbon-filled fracture reflections, nevertheless subsurface heterogeneity, antenna coupling changes, and other sources of noise will likely make it difficult to observe these changes in GPR field data. This indicates that the routine application of common-offset GPR reflection methods for detection of hydrocarbon-filled fractures will be problematic. Ideal cases will require appropriately processed, high-quality GPR data, ground-truth information, and detailed knowledge of subsurface physical properties. Conversely, the sensitivity of GPR methods to changes in subsurface physical properties as demonstrated by the numerical and experimental results suggests the potential of using GPR methods as a monitoring tool. GPR methods may be suited for monitoring pumping and tracer tests, changes in site hydrologic conditions, and remediation activities.The suitability of common-offset ground-penetrating radar (GPR) to detect free-phase hydrocarbons

  1. Electrical Resistivity Tomography and Ground Penetrating Radar for locating buried petrified wood sites: a case study in the natural monument of the Petrified Forest of Evros, Greece

    Science.gov (United States)

    Vargemezis, George; Diamanti, Nectaria; Tsourlos, Panagiotis; Fikos, Ilias

    2014-05-01

    A geophysical survey was carried out in the Petrified Forest of Evros, the northernmost regional unit of Greece. This collection of petrified wood has an age of approximately 35 million years and it is the oldest in Greece (i.e., older than the well-known Petrified Forest of Lesvos island located in the North Aegean Sea and which is possibly the largest of the petrified forests worldwide). Protection, development and maintenance projects still need to be carried out at the area despite all fears regarding the forest's fate since many petrified logs remain exposed both in weather conditions - leading to erosion - and to the public. This survey was conducted as part of a more extensive framework regarding the development and protection of this natural monument. Geophysical surveying has been chosen as a non-destructive investigation method since the area of application is both a natural ecosystem and part of cultural heritage. Along with electrical resistivity tomography (ERT), ground penetrating radar (GPR) surveys have been carried out for investigating possible locations of buried fossilized tree trunks. The geoelectrical sections derived from ERT data in combination with the GPR profiles provided a broad view of the subsurface. Two and three dimensional subsurface geophysical images of the surveyed area have been constructed, pointing out probable locations of petrified logs. Regarding ERT, petrified trunks have been detected as high resistive bodies, while lower resistivity values were more related to the surrounding geological materials. GPR surveying has also indicated buried petrified log locations. As these two geophysical methods are affected in different ways by the subsurface conditions, the combined use of both techniques enhanced our ability to produce more reliable interpretations of the subsurface. After the completion of the geophysical investigations of this first stage, petrified trunks were revealed after a subsequent excavation at indicated

  2. Search for an artificially buried karst cave entrance using ground penetrating radar: a successful case of locating the S-19 Cave in the Mt. Kanin massif (NW Slovenia

    Directory of Open Access Journals (Sweden)

    Andrej Gosar

    2016-05-01

    Full Text Available The S-19 Cave was with its explored depth of 177 m one of the most important caves of the Mt. Kanin massif, but after its discovery in 1974, a huge snow avalanche protection dyke was constructed across the cave entrance. To excavate the buried cave, the accurate location of the cave had to be determined first. Since the entrance coordinates were incorrect and no markers were available, application of geophysical techniques was necessary to do this. A Ground Penetrating Radar (GPR with special 50 MHz rough terrain antennas was selected as the single suitable geophysical method for the given conditions where thick debris overlay a rugged limestone surface. Nevertheless, it was not possible to directly detect the relatively narrow cave entrance itself due to data resolution limits. However, a historical photo of the area showed that the cave entrance was located in a local depression, which therefore represented the main target of the GPR survey. Seven GPR profiles were measured across the rough and steep surface causing difficulties in traversing the area with sensitive research equipment. In all recorded radargrams a small depression was clearly imaged under debris, and recognized as a topographic feature with the cave entrance. Based on the GPR data interpretation, the exact location for digging was determined and the thickness of debris assessed at 6.5–7 m. A massive excavation by a dredger resulted in a successful opening of the cave entrance, confirming both its geophysically determined location and its estimated depth. The application of an advanced geophysical method was therefore proven successful in providing a solution to this specific case in karst exploration and an important cave was saved.

  3. 探地雷达在治理城市塌陷区中的应用%GROUND PENETRATING RADAR APPLIED IN TREATMENT OF SUBSIDENCE IN A CITY

    Institute of Scientific and Technical Information of China (English)

    施延昭; 张国鸿

    2016-01-01

    Ground penetrating radar is a means to detect internal structure and distribution law of underground medium by broadband high-frequency electromagnetic wave, and has been widely applied in many fields such as hazard geology exploration, geotechnical survey and engineering quality inspection. This paper brought an example of the technique used in engineering quality inspection of treatment of city subsidence, by comparison of the detection result of the radar with two high-frequency antennas with 2D model forward modeling result, gave a definite conclusion on the treatment quality and whether a hidden subsidence exists or not.%探地雷达是利用宽带高频电磁波以脉冲形式来探测地表之下介质内部结构分布规律的一种地球物理方法。它广泛用于灾害地质勘查、岩土工程调查和工程质量检测等众多领域。本文给出了一个在治理城市塌陷区的工程质量检测中的应用实例,通过两种高频天线的探地雷达检测和二维模型正演结果对比,对塌陷区治理质量以及是否存在隐伏塌陷隐患给出了明确的结语。

  4. Experimental Study on Underground Cavity Detection By Ground Penetrating Radar%探地雷达检测地下空洞的实验研究

    Institute of Scientific and Technical Information of China (English)

    孔令翔; 李青; 赵志鹏; 王先进; 周泽正; 万帅

    2016-01-01

    通过分析电磁波在地下介质中的传播规律,介绍了探地雷达检测地下空洞的基本原理。利用时域有限差分方法进行正演模拟,初步了解了空洞在反射波谱上的图像特征。制作实验装置,对比了空洞试验模型在不同实验条件下测量所得到的反射波形之间的图像差异,并进行波速标定,验证探测结果的准确性。通过分析研究,总结出了地下空洞在雷达波谱上的图像识别规律,为现场测量和危害评估提供理论支持,对于防灾减灾有一定的促进作用。%Through analyzing the electromagnetic wave propagation in underground medium, introduce the basic principle of detecting the underground cavity by GPR(Ground Penetrating Radar). Using FDTD (Finite Difference Time Domain) in the forward simulation, the characteristics of the reflection spectrum about the cavity can be preliminarily understood. Make an experimental device and establish different kinds of cavity models. Contrast the differences of the reflection waveform between the different models. Then compare the accuracy of detection results through the wave velocity calibration. The image recognition rules of underground cavity in radar spectrum are summarized. It provides theoretical support for the detection and the damage assessment, and is very effective in disaster prevention and reduction.

  5. The Triglav Glacier (South-Eastern Alps, Slovenia): Volume Estimation, Internal Characterization and 2000-2013 Temporal Evolution by Means of Ground Penetrating Radar Measurements

    Science.gov (United States)

    Del Gobbo, Costanza; Colucci, Renato R.; Forte, Emanuele; Triglav Čekada, Michaela; Zorn, Matija

    2016-08-01

    It is well known that small glaciers of mid latitudes and especially those located at low altitude respond suddenly to climate changes both on local and global scale. For this reason their monitoring as well as evaluation of their extension and volume is essential. We present a ground penetrating radar (GPR) dataset acquired on September 23 and 24, 2013 on the Triglav glacier to identify layers with different characteristics (snow, firn, ice, debris) within the glacier and to define the extension and volume of the actual ice. Computing integrated and interpolated 3D using the whole GPR dataset, we estimate that at the moment of data acquisition the ice area was 3800 m2 and the ice volume 7400 m3. Its average thickness was 1.95 m while its maximum thickness was slightly more than 5 m. Here we compare the results with a previous GPR survey acquired in 2000. A critical review of the historical data to find the general trend and to forecast a possible evolution is also presented. Between 2000 and 2013, we observed relevant changes in the internal distribution of the different units (snow, firn, ice) and the ice volume reduced from about 35,000 m3 to about 7400 m3. Such result can be achieved only using multiple GPR surveys, which allow not only to assess the volume occupied by a glacial body, but also to image its internal structure and the actual ice volume. In fact, by applying one of the widely used empirical volume-area relations to infer the geometrical parameters of the glacier, a relevant underestimation of ice-loss would be achieved.

  6. Estimation of soil hydraulic parameters in the field by integrated hydrogeophysical inversion of time-lapse ground-penetrating radar data

    KAUST Repository

    Jadoon, Khan

    2012-01-01

    An integrated hydrogeophysical inversion approach was used to remotely infer the unsaturated soil hydraulic parameters from time-lapse ground-penetrating radar (GPR) data collected at a fixed location over a bare agricultural field. The GPR model combines a full-waveform solution of Maxwell\\'s equations for three-dimensional wave propaga- tion in planar layered media together with global reflection and transmission functions to account for the antenna and its interactions with the medium. The hydrological simu- lator HYDRUS-1D was used with a two layer single- and dual-porosity model. The radar model was coupled to the hydrodynamic model, such that the soil electrical properties (permitivity and conductivity) that serve as input to the GPR model become a function of the hydrodynamic model output (water content), thereby permiting estimation of the soil hydraulic parameters from the GPR data in an inversion loop. To monitor the soil water con- tent dynamics, time-lapse GPR and time domain reflectometry (TDR) measurements were performed, whereby only GPR data was used in the inversion. Significant effects of water dynamics were observed in the time-lapse GPR data and in particular precipitation and evaporation events were clearly visible. The dual porosity model provided betier results compared to the single porosity model for describing the soil water dynamics, which is sup- ported by field observations of macropores. Furthermore, the GPR-derived water content profiles reconstructed from the integrated hydrogeophysical inversion were in good agree- ment with TDR observations. These results suggest that the proposed method is promising for non-invasive characterization of the shallow subsurface hydraulic properties and moni- toring water dynamics at the field scale. © Soil Science Society of America.

  7. Development and evaluation of new coupling system for lower limb prostheses with acoustic alarm system.

    Science.gov (United States)

    Eshraghi, Arezoo; Osman, Noor Azuan Abu; Gholizadeh, Hossein; Ahmadian, Jalil; Rahmati, Bizhan; Abas, Wan Abu Bakar Wan

    2013-01-01

    Individuals with lower limb amputation need a secure suspension system for their prosthetic devices. A new coupling system was developed that is capable of suspending the prosthesis. The system's safety is ensured through an acoustic alarm system. This article explains how the system works and provides an in vivo evaluation of the device with regard to pistoning during walking. The system was designed to be used with silicone liners and is based on the requirements of prosthetic suspension systems. Mechanical testing was performed using a universal testing machine. The pistoning during walking was measured using a motion analysis system. The new coupling device produced significantly less pistoning compared to a common suspension system (pin/lock). The safety alarm system would buzz if the suspension was going to fail. The new coupling system could securely suspend the prostheses in transtibial amputees and produced less vertical movement than the pin/lock system.

  8. System and method for investigating sub-surface features of a rock formation using compressional acoustic sources

    Science.gov (United States)

    Vu, Cung Khac; Skelt, Christopher; Nihei, Kurt; Johnson, Paul A.; Guyer, Robert; Ten Cate, James A.; Le Bas, Pierre-Yves; Larmat, Carene S.

    2016-09-27

    A system and method for investigating rock formations outside a borehole are provided. The method includes generating a first compressional acoustic wave at a first frequency by a first acoustic source; and generating a second compressional acoustic wave at a second frequency by a second acoustic source. The first and the second acoustic sources are arranged within a localized area of the borehole. The first and the second acoustic waves intersect in an intersection volume outside the borehole. The method further includes receiving a third shear acoustic wave at a third frequency, the third shear acoustic wave returning to the borehole due to a non-linear mixing process in a non-linear mixing zone within the intersection volume at a receiver arranged in the borehole. The third frequency is equal to a difference between the first frequency and the second frequency.

  9. Design and Instrumentation of a Measurement and Calibration System for an Acoustic Telemetry System

    Directory of Open Access Journals (Sweden)

    Zhiqun Deng

    2010-03-01

    Full Text Available The Juvenile Salmon Acoustic Telemetry System (JSATS is an active sensing technology developed by the U.S. Army Corps of Engineers, Portland District, for detecting and tracking small fish. It is used primarily for evaluating behavior and survival of juvenile salmonids migrating through the Federal Columbia River Power System to the Pacific Ocean. It provides critical data for salmon protection and development of more “fish-friendly” hydroelectric facilities. The objective of this study was to design and build a Measurement and Calibration System (MCS for evaluating the JSATS components, because the JSATS requires comprehensive acceptance and performance testing in a controlled environment before it is deployed in the field. The MCS consists of a reference transducer, a water test tank lined with anechoic material, a motion control unit, a reference receiver, a signal conditioner and amplifier unit, a data acquisition board, MATLAB control and analysis interface, and a computer. The fully integrated MCS has been evaluated successfully at various simulated distances and using different encoded signals at frequencies within the bandwidth of the JSATS transmitter. The MCS provides accurate acoustic mapping capability in a controlled environment and automates the process that allows real-time measurements and evaluation of the piezoelectric transducers, sensors, or the acoustic fields. The MCS has been in use since 2009 for acceptance and performance testing of, and further improvements to, the JSATS.

  10. Thermal-Acoustic Fatigue of a Multilayer Thermal Protection System in Combined Extreme Environments

    Directory of Open Access Journals (Sweden)

    Liu Liu

    2014-06-01

    Full Text Available In order to ensure integrity of thermal protection system (TPS structure for hypersonic vehicles exposed to severe operating environments, a study is undertaken to investigate the response and thermal-acoustic fatigue damage of a representative multilayer TPS structure under combined thermal and acoustic loads. An unsteady-state flight of a hypersonic vehicle is composed of a series of steady-state snapshots, and for each snapshot an acoustic load is imposed to a static steady-state TPS structure. A multistep thermal-acoustic fatigue damage intensity analysis procedure is given and consists of a heat transfer analysis, a nonlinear thermoelastic analysis, and a random response analysis under a combined loading environment and the fatigue damage intensity has been evaluated with two fatigue analysis techniques. The effects of thermally induced deterministic stress and nondeterministic dynamic stress due to the acoustic loading have been considered in the damage intensity estimation with a maximum stress fatigue model. The results show that the given thermal-acoustic fatigue intensity estimation procedure is a viable approach for life prediction of TPS structures under a typical mission cycle with combined loadings characterized by largely different time-scales. A discussion of the effects of the thermal load, the acoustic load, and fatigue analysis methodology on the fatigue damage intensity has been provided.

  11. AMADEUS - The Acoustic Neutrino Detection Test System of the ANTARES Deep-Sea Neutrino Telescope

    CERN Document Server

    Aguilar, J A; Albert, A; Anghinolfi, M; Anton, G; Anvar, S; Ardid, M; Jesus, A C Assis; Astraatmadja, T; Aubert, J-J; Auer, R; Barbarito, E; Baret, B; Basa, S; Bazzotti, M; Bertin, V; Biagi, S; Bigongiari, C; Bou-Cabo, M; Bouwhuis, M C; Brown, A; Brunner, J; Busto, J; Camarena, F; Capone, A; Cârloganu, C; Carminati, G; Carr, J; Cassano, B; Castorina, E; Cavasinni, V; Cecchini, S; Ceres, A; Charvis, Ph; Chiarusi, T; Sen, N Chon; Circella, M; Coniglione, R; Costantini, H; Cottini, N; Coyle, P; Curtil, C; De Bonis, G; Decowski, M P; Dekeyser, I; Deschamps, A; Distefano, C; Donzaud, C; Dornic, D; Drouhin, D; Eberl, T; Emanuele, U; Ernenwein, J-P; Escoffier, S; Fehr, F; Fiorello, C; Flaminio, V; Fritsch, U; Fuda, J-L; Gay, P; Giacomelli, G; Gómez-González, J P; Graf, K; Guillard, G; Halladjian, G; Hallewell, G; van Haren, H; Heijboer, A J; Heine, E; Hello, Y; Hernández-Rey, J J; Herold, B; Hößl, J; de Jong, M; Kalantar-Nayestanaki, N; Kalekin, O; Kappes, A; Katz, U; Keller, P; Kooijman, P; Kopper, C; Kouchner, A; Kretschmer, W; Lahmann, R; Lamare, P; Lambard, G; Larosa, G; Laschinsky, H; Le Provost, H; Lefèvre, D; Lelaizant, G; Lim, G; Presti, D Lo; Loehner, H; Loucatos, S; Louis, F; Lucarelli, F; Mangano, S; Marcelin, M; Margiotta, A; Martinez-Mora, J A; Mazure, A; Mongelli, M; Montaruli, T; Morganti, M; Moscoso, L; Motz, H; Naumann, C; Neff, M; Ostasch, R; Palioselitis, D; Pavalas, G E; Payre, P; Petrovic, J; Picot-Clemente, N; Picq, C; Popa, V; Pradier, T; Presani, E; Racca, C; Radu, A; Reed, C; Riccobene, G; Richardt, C; Rujoiu, M; Ruppi, M; Russo, G V; Salesa, F; Sapienza, P; Schöck, F; Schuller, J-P; Shanidze, R; Simeone, F; Spurio, M; Steijger, J J M; Stolarczyk, Th; Taiuti, M; Tamburini, C; Tasca, L; Toscano, S; Vallage, B; Van Elewyck, V; Vannoni, G; Vecchi, M; Vernin, P; Wijnker, G; de Wolf, E; Yepes, H; Zaborov, D; Zornoza, J D; Zúñiga, J; 10.1016/j.nima.2010.09.053

    2010-01-01

    The AMADEUS (ANTARES Modules for the Acoustic Detection Under the Sea) system which is described in this article aims at the investigation of techniques for acoustic detection of neutrinos in the deep sea. It is integrated into the ANTARES neutrino telescope in the Mediterranean Sea. Its acoustic sensors, installed at water depths between 2050 and 2300 m, employ piezo-electric elements for the broad-band recording of signals with frequencies ranging up to 125 kHz. The typical sensitivity of the sensors is around -145 dB re 1V/muPa (including preamplifier). Completed in May 2008, AMADEUS consists of six "acoustic clusters", each comprising six acoustic sensors that are arranged at distances of roughly 1 m from each other. Two vertical mechanical structures (so-called lines) of the ANTARES detector host three acoustic clusters each. Spacings between the clusters range from 14.5 to 340 m. Each cluster contains custom-designed electronics boards to amplify and digitise the acoustic signals from the sensors. An on...

  12. The APL-UW Multiport Acoustic Projector System

    Science.gov (United States)

    2009-12-01

    moni- tor, power amplifier drive current monitor, “bare” acoustic input, and IRIG -M. Due to the high sampling rate, it was not possible to capture all...decoded from the IRIG channel. The marktime is 20 seconds later, and may be different by 1 second from the target marktime recorded in the file header

  13. Measuring System for Interference Optical Fiber Acoustic Emission①

    Institute of Scientific and Technical Information of China (English)

    LUQizhu; ZHENGShengxuan

    1997-01-01

    A type of interference optical fiber acoustic emission sensor is described.With 10-10 m level resolution,megahertz-level frequency and response time less than 1 μs,this sensor possesses prominent measuring stability and can be used in state supervision and trouble diagnosis.

  14. Data Processing for Image of Ground Penetrating Radar based on k-means Algorithms%基于k-means算法的树根雷达图像数据处理研究

    Institute of Scientific and Technical Information of China (English)

    刘君; 高林

    2012-01-01

    文章通过研究探地雷达探测原理,提出一种数据处理成像方法,用于对通过地下树根的探测得到的雷达图像进行处理,实现对树根的无损检测.经验征,该方法有一定效果,这将为探地雷达在林业和农业方面的进一步应用提供基础,同时表明了将探地雷达用于树木无损检测的可行性.%A data processing imaging method was proposed via 9tudying detecting principles of ground penetrating radar, which used to processing radar images of underground tree roots, in order to achieve the goal of nondestructive testing for tree roots. The method has proved a certain effects, which provided basis for further application of ground penetrating radar in forestry and agriculture, meanwhile, the feasibility of applying ground penetrating radar in nondestructive testing tree roots was verified.

  15. AMADEUS—The acoustic neutrino detection test system of the ANTARES deep-sea neutrino telescope

    Science.gov (United States)

    Aguilar, J. A.; Al Samarai, I.; Albert, A.; Anghinolfi, M.; Anton, G.; Anvar, S.; Ardid, M.; Assis Jesus, A. C.; Astraatmadja, T.; Aubert, J.-J.; Auer, R.; Barbarito, E.; Baret, B.; Basa, S.; Bazzotti, M.; Bertin, V.; Biagi, S.; Bigongiari, C.; Bou-Cabo, M.; Bouwhuis, M. C.; Brown, A.; Brunner, J.; Busto, J.; Camarena, F.; Capone, A.; Cârloganu, C.; Carminati, G.; Carr, J.; Cassano, B.; Castorina, E.; Cavasinni, V.; Cecchini, S.; Ceres, A.; Charvis, Ph.; Chiarusi, T.; Chon Sen, N.; Circella, M.; Coniglione, R.; Costantini, H.; Cottini, N.; Coyle, P.; Curtil, C.; de Bonis, G.; Decowski, M. P.; Dekeyser, I.; Deschamps, A.; Distefano, C.; Donzaud, C.; Dornic, D.; Drouhin, D.; Eberl, T.; Emanuele, U.; Ernenwein, J.-P.; Escoffier, S.; Fehr, F.; Fiorello, C.; Flaminio, V.; Fritsch, U.; Fuda, J.-L.; Gay, P.; Giacomelli, G.; Gómez-González, J. P.; Graf, K.; Guillard, G.; Halladjian, G.; Hallewell, G.; van Haren, H.; Heijboer, A. J.; Heine, E.; Hello, Y.; Hernández-Rey, J. J.; Herold, B.; Hößl, J.; de Jong, M.; Kalantar-Nayestanaki, N.; Kalekin, O.; Kappes, A.; Katz, U.; Keller, P.; Kooijman, P.; Kopper, C.; Kouchner, A.; Kretschmer, W.; Lahmann, R.; Lamare, P.; Lambard, G.; Larosa, G.; Laschinsky, H.; Le Provost, H.; Lefèvre, D.; Lelaizant, G.; Lim, G.; Lo Presti, D.; Loehner, H.; Loucatos, S.; Louis, F.; Lucarelli, F.; Mangano, S.; Marcelin, M.; Margiotta, A.; Martinez-Mora, J. A.; Mazure, A.; Mongelli, M.; Montaruli, T.; Morganti, M.; Moscoso, L.; Motz, H.; Naumann, C.; Neff, M.; Ostasch, R.; Palioselitis, D.; Păvălaş, G. E.; Payre, P.; Petrovic, J.; Picot-Clemente, N.; Picq, C.; Popa, V.; Pradier, T.; Presani, E.; Racca, C.; Radu, A.; Reed, C.; Riccobene, G.; Richardt, C.; Rujoiu, M.; Ruppi, M.; Russo, G. V.; Salesa, F.; Sapienza, P.; Schöck, F.; Schuller, J.-P.; Shanidze, R.; Simeone, F.; Spurio, M.; Steijger, J. J. M.; Stolarczyk, Th.; Taiuti, M.; Tamburini, C.; Tasca, L.; Toscano, S.; Vallage, B.; van Elewyck, V.; Vannoni, G.; Vecchi, M.; Vernin, P.; Wijnker, G.; de Wolf, E.; Yepes, H.; Zaborov, D.; Zornoza, J. D.; Zúñiga, J.

    2011-01-01

    The AMADEUS (ANTARES Modules for the Acoustic Detection Under the Sea) system which is described in this article aims at the investigation of techniques for acoustic detection of neutrinos in the deep sea. It is integrated into the ANTARES neutrino telescope in the Mediterranean Sea. Its acoustic sensors, installed at water depths between 2050 and 2300 m, employ piezo-electric elements for the broad-band recording of signals with frequencies ranging up to 125 kHz. The typical sensitivity of the sensors is around -145 dB re 1 V/μPa (including preamplifier). Completed in May 2008, AMADEUS consists of six “acoustic clusters”, each comprising six acoustic sensors that are arranged at distances of roughly 1 m from each other. Two vertical mechanical structures (so-called lines) of the ANTARES detector host three acoustic clusters each. Spacings between the clusters range from 14.5 to 340 m. Each cluster contains custom-designed electronics boards to amplify and digitise the acoustic signals from the sensors. An on-shore computer cluster is used to process and filter the data stream and store the selected events. The daily volume of recorded data is about 10 GB. The system is operating continuously and automatically, requiring only little human intervention. AMADEUS allows for extensive studies of both transient signals and ambient noise in the deep sea, as well as signal correlations on several length scales and localisation of acoustic point sources. Thus the system is excellently suited to assess the background conditions for the measurement of the bipolar pulses expected to originate from neutrino interactions.

  16. Comparison of PAM Systems for Acoustic Monitoring and Further Risk Mitigation Application.

    Science.gov (United States)

    Ludwig, Stefan; Kreimeyer, Roman; Knoll, Michaela

    2016-01-01

    We present results of the SIRENA 2011 research cruises conducted by the NATO Undersea Research Centre (NURC) and joined by the Research Department for Underwater Acoustics and Geophysics (FWG), Bundeswehr Technical Centre (WTD 71) and the Universities of Kiel and Pavia. The cruises were carried out in the Ligurian Sea. The main aim of the FWG was to test and evaluate the newly developed towed hydrophone array as a passive acoustic monitoring (PAM) tool for risk mitigation applications. The system was compared with the PAM equipment used by the other participating institutions. Recorded sounds were used to improve an automatic acoustic classifier for marine mammals, and validated acoustic detections by observers were compared with the results of the classifier.

  17. Inference of multi-Gaussian property fields by probabilistic inversion of crosshole ground penetrating radar data using an improved dimensionality reduction

    Science.gov (United States)

    Hunziker, Jürg; Laloy, Eric; Linde, Niklas

    2016-04-01

    Deterministic inversion procedures can often explain field data, but they only deliver one final subsurface model that depends on the initial model and regularization constraints. This leads to poor insights about the uncertainties associated with the inferred model properties. In contrast, probabilistic inversions can provide an ensemble of model realizations that accurately span the range of possible models that honor the available calibration data and prior information allowing a quantitative description of model uncertainties. We reconsider the problem of inferring the dielectric permittivity (directly related to radar velocity) structure of the subsurface by inversion of first-arrival travel times from crosshole ground penetrating radar (GPR) measurements. We rely on the DREAM_(ZS) algorithm that is a state-of-the-art Markov chain Monte Carlo (MCMC) algorithm. Such algorithms need several orders of magnitude more forward simulations than deterministic algorithms and often become infeasible in high parameter dimensions. To enable high-resolution imaging with MCMC, we use a recently proposed dimensionality reduction approach that allows reproducing 2D multi-Gaussian fields with far fewer parameters than a classical grid discretization. We consider herein a dimensionality reduction from 5000 to 257 unknowns. The first 250 parameters correspond to a spectral representation of random and uncorrelated spatial fluctuations while the remaining seven geostatistical parameters are (1) the standard deviation of the data error, (2) the mean and (3) the variance of the relative electric permittivity, (4) the integral scale along the major axis of anisotropy, (5) the anisotropy angle, (6) the ratio of the integral scale along the minor axis of anisotropy to the integral scale along the major axis of anisotropy and (7) the shape parameter of the Matérn function. The latter essentially defines the type of covariance function (e.g., exponential, Whittle, Gaussian). We present

  18. Ground-penetrating radar images of a dye tracer test within the unsaturated zone at the Susquehanna-Shale Hills CZO

    Science.gov (United States)

    Pitman, Lacey M.

    Dye tracer and time-lapse ground-penetrating radar (GPR) were used to image preferential flow paths in the shallow, unsaturated zone on hillslopes in two adjacent watersheds within the Susquehanna-Shale Hills Critical Zone Observatory (CZO). At each site we injected about 50 L of water mixed with brilliant blue dye (4 g/L) into a trench cut perpendicular to the slope (˜1.0 m long by ˜0.20 m wide by ˜0.20 m deep) to create a line of infiltration. GPR (800 MHz antennae with constant offset) was used to monitor the movement of the dye tracer downslope on a 1.0 m x 2.0 m grid with a 0.05 m line spacing. The site was then excavated and the stained pathways photographed to document the dye movement. We saw a considerable difference in the pattern of shallow preferential flow between the two sites despite similar soil characteristics and slope position. Both sites showed dye penetrating down to saprolite (˜0.40 m); however, lateral flow migration between the two sites was different. At the Missed Grouse field site, the lateral migration was ˜0.55 m as an evenly dispersed plume, but at distance of 0.70 m a finger of dye was observed. At the Shale Hills field site, the total lateral flow was ˜0.40 m, dye was barely visible until the excavation reached ˜0.10 m, and there was more evidence of distinct fingering in the vertical direction. Based on laboratory and field experiments as well as processing of the radargrams, the following conclusions were drawn: 1) time-lapse GPR successfully delineated the extent of lateral flow, but the GPR resolution was insufficient to detect small fingers of dye; 2) there was not a distinct GPR reflection at the regolith-saprock boundary, but this interface could be estimated from the extent of signal attenuation; 3) the preliminary soil moisture conditions may explain differences in the extent of infiltration at the two sites; 4) rapid infiltration into the underlying saprock limited the extent of shallow lateral flow at both sites and

  19. Effects of near surface soil moisture profiles during evaporation on far-field ground-penetrating radar data: A numerical study

    KAUST Repository

    Moghadas, Davood

    2013-01-01

    We theoretically investigated the effect of vapor flow on the drying front that develops in soils when water evaporates from the soil surface and on GPR data. The results suggest the integration of the full-wave GPR model with a coupled water, vapor, and heat flow model to accurately estimate the soil hydraulic properties. We investigated the Effects of a drying front that emerges below an evaporating soil surface on the far-field ground-penetrating radar (GPR) data. First, we performed an analysis of the width of the drying front in soils with 12 different textures by using an analytical model. Then, we numerically simulated vertical soil moisture profiles that develop during evaporation for the soil textures. We performed the simulations using a Richards flow model that considers only liquid water flow and a model that considers coupled water, vapor, and heat flows. The GPR signals were then generated from the simulated soil water content profiles taking into account the frequency dependency of apparent electrical conductivity and dielectric permittivity. The analytical approach indicated that the width of the drying front at the end of Stage I of the evaporation was larger in silty soils than in other soil textures and smaller in sandy soils. We also demonstrated that the analytical estimate of the width of the drying front can be considered as a proxy for the impact that a drying front could have on far-field GPR data. The numerical simulations led to the conclusion that vapor transport in soil resulted in S-shaped soil moisture profiles, which clearly influenced the GPR data. As a result, vapor flow needs to be considered when GPR data are interpreted in a coupled inversion approach. Moreover, the impact of vapor flow on the GPR data was larger for silty than for sandy soils. These Effects on the GPR data provide promising perspectives regarding the use of radars for evaporation monitoring. © Soil Science Society of America 5585 Guilford Rd., Madison, WI

  20. Analysis of ground penetrating radar data from the tunnel beneath the Temple of the Feathered Serpent in Teotihuacan, Mexico, using new multi-cross algorithms

    Science.gov (United States)

    López-Rodríguez, Flor; Velasco-Herrera, Víctor M.; Álvarez-Béjar, Román; Gómez-Chávez, Sergio; Gazzola, Julie

    2016-11-01

    The ground penetrating radar (GPR) -a non-invasive method based on the emission of electromagnetic waves and the reception of their reflections at the dielectric constant and electrical conductivity discontinuities of the materials surveyed- may be applied instead of the destructive and invasive methods used to find water in celestial bodies. As multichannel equipment is increasingly used, we developed two algorithms for multivariable wavelet analysis of GPR signals -multi-cross wavelet (MCW) and Fourier multi-cross function (FMC)- and applied them to analyze raw GPR traces of archeological subsurface strata. The traces were from the tunnel located beneath the Temple of the Feathered Serpent (The Citadel, Teotihuacan, Mexico), believed to represent the underworld, an outstanding region of the Mesoamerican mythology, home of telluric forces emanating from deities, where life was constantly created and recreated. GPR profiles obtained with 100 MHz antennas suggested the tunnel is 12-14 m deep and 100-120 m long with three chambers at its end, interpretations that were confirmed by excavations in 2014. Archeologists believe that due to the tunnel's sacredness and importance, one of the chambers may be the tomb of a ruler of the ancient city. The MCW and FMC algorithms determined the periods of subsurface strata of the tunnel. GPR traces inside-and-outside the tunnel/chamber, outside the tunnel/chamber and inside the tunnel/chamber analyzed with the MCW and filtered FMC algorithms determined the periods of the tunnel and chamber fillings, clay and matrix (limestone-clay compound). The tunnel filling period obtained by MCW analysis (14.37 ns) reflects the mixed limestone-clay compound of this stratum since its value is close to that of the period of the matrix (15.22 ns); periods of the chamber filling (11.40 ± 0.40 ns) and the matrix (11.40 ± 1.00 ns) were almost identical. FMC analysis of the tunnel obtained a period (5.08 ± 1.08 ns) close to that of the chamber

  1. Fusion of Satellite Multispectral Images Based on Ground-Penetrating Radar (GPR Data for the Investigation of Buried Concealed Archaeological Remains

    Directory of Open Access Journals (Sweden)

    Athos Agapiou

    2017-06-01

    Full Text Available The paper investigates the superficial layers of an archaeological landscape based on the integration of various remote sensing techniques. It is well known in the literature that shallow depths may be rich in archeological remains, which generate different signal responses depending on the applied technique. In this study three main technologies are examined, namely ground-penetrating radar (GPR, ground spectroscopy, and multispectral satellite imagery. The study aims to propose a methodology to enhance optical remote sensing satellite images, intended for archaeological research, based on the integration of ground based and satellite datasets. For this task, a regression model between the ground spectroradiometer and GPR is established which is then projected to a high resolution sub-meter optical image. The overall methodology consists of nine steps. Beyond the acquirement of the in-situ measurements and their calibration (Steps 1–3, various regression models are examined for more than 70 different vegetation indices (Steps 4–5. The specific data analysis indicated that the red-edge position (REP hyperspectral index was the most appropriate for developing a local fusion model between ground spectroscopy data and GPR datasets (Step 6, providing comparable results with the in situ GPR measurements (Step 7. Other vegetation indices, such as the normalized difference vegetation index (NDVI, have also been examined, providing significant correlation between the two datasets (R = 0.50. The model is then projected to a high-resolution image over the area of interest (Step 8. The proposed methodology was evaluated with a series of field data collected from the Vésztő-Mágor Tell in the eastern part of Hungary. The results were compared with in situ magnetic gradiometry measurements, indicating common interpretation results. The results were also compatible with the preliminary archaeological investigations of the area (Step 9. The overall

  2. Advances in monitoring dynamic hydrologic conditions in the vadose zone through automated high-resolution ground-penetrating radar imaging and analysis

    Science.gov (United States)

    Mangel, Adam R.

    This body of research focuses on resolving physical and hydrological heterogeneities in the subsurface with ground-penetrating radar (GPR). Essentially, there are two facets of this research centered on the goal of improving the collective understanding of unsaturated flow processes: i) modifications to commercially available equipment to optimize hydrologic value of the data and ii) the development of novel methods for data interpretation and analysis in a hydrologic context given the increased hydrologic value of the data. Regarding modifications to equipment, automation of GPR data collection substantially enhances our ability to measure changes in the hydrologic state of the subsurface at high spatial and temporal resolution (Chapter 1). Additionally, automated collection shows promise for quick high-resolution mapping of dangerous subsurface targets, like unexploded ordinance, that may have alternate signals depending on the hydrologic environment (Chapter 5). Regarding novel methods for data inversion, dispersive GPR data collected during infiltration can constrain important information about the local 1D distribution of water in waveguide layers (Chapters 2 and 3), however, more data is required for reliably analyzing complicated patterns produced by the wetting of the soil. In this regard, data collected in 2D and 3D geometries can further illustrate evidence of heterogeneous flow, while maintaining the content for resolving wave velocities and therefore, water content. This enables the use of algorithms like reflection tomography, which show the ability of the GPR data to independently resolve water content distribution in homogeneous soils (Chapter 5). In conclusion, automation enables the non-invasive study of highly dynamic hydrologic processes by providing the high resolution data required to interpret and resolve spatial and temporal wetting patterns associated with heterogeneous flow. By automating the data collection, it also allows for the novel

  3. Three-dimensional photoacoustic imaging system with a 4f aspherical acoustic lens

    Science.gov (United States)

    Jen, En; Lin, Hsintien; Chiang, Huihua Kenny

    2016-08-01

    Photoacoustic (PA) imaging is a modality for achieving high-contrast images of blood vessels or tumors. Most PA imaging systems use complex reconstruction algorithms under conventional linear array transducers. We introduced the optical simulating method to improve the acoustic lens design and obtain a PA imaging system with improved spatial revolution (a 0.5-mm point spread function and a lateral image resolution of more than 1 mm) is realized using a 4f aspherical acoustic lens. The acoustic lens approach improved the image resolution and enabled direct reconstruction of three-dimensional (3-D) PA images. The system demonstrated a lateral resolution of more than 1 mm, a field of view of 8.5 deg, and a depth of focus of 10 mm. The system displays great potential for developing a real-time 3-D PA camera system for biomedical ultrasound imaging applications.

  4. 探地雷达法在水工输水隧洞衬砌混凝土检测中的应用%Application of ground-penetrating radar method in detection of lining concrete in hydraulic tunnel

    Institute of Scientific and Technical Information of China (English)

    汪魁峰

    2014-01-01

    The non-destructive test of concrete structure is the importent problem in civil engineering field and is regarded as the key to ensure safety and durability of large concrete construction .Based on the in-troduction of rule and method of non-destructive test on ground-penetrating radar , the paper took hydrau-lic tunnel lining concrete as the measured object , and applied ground-penetrating radar method to test and verify concrete thickness , internal rebar distribution and internal defect .Through the comparison between the detection results by ground-penetrating radar and that by drilling core ,it analyzed the precision and deviation of ground-penetrating radar method .The research shows the results of non-destructive test by ground-penetrating radar method are reliable and can meet the requirement of quality control in construc -tion of engineering , the application of non-destructive test in water conservancy engineering is feasible .%混凝土结构的无损检测是工程界普遍重视的问题,也是保证结构安全的关键。在介绍探地雷达法无损检测原理方法基础上,以水工输水隧洞衬砌混凝土为被测对象,应用探地雷达法对衬砌混凝土厚度、内置钢筋分布、内部缺陷等进行测试、标识,并与钻芯法取芯检测结果比较,分析探地雷达法无损检测数据的精确度和偏差程度。结果表明:探地雷达法无损检测结果可信度高,能满足工程建设质量控制的要求,其在水利工程无损检测的应用是可行的。

  5. Acoustically shielded exhaust system for high thrust jet engines

    Science.gov (United States)

    Carey, John P. (Inventor); Lee, Robert (Inventor); Majjigi, Rudramuni K. (Inventor)

    1995-01-01

    A flade exhaust nozzle for a high thrust jet engine is configured to form an acoustic shield around the core engine exhaust flowstream while supplementing engine thrust during all flight conditions, particularly during takeoff. The flade airflow is converted from an annular 360.degree. flowstream to an arcuate flowstream extending around the lower half of the core engine exhaust flowstream so as to suppress exhaust noise directed at the surrounding community.

  6. Underwater Acoustic Network as a Deployable Positioning System

    Science.gov (United States)

    2012-06-01

    Teledyne Benthos modems have a number of settings that can be adjusted for a specific mode of operation. Settings are easily changed in air at short...S/N 10R-022508); Teledyne Benthos Transducer (Part #C-270-167-1, Model #AT-440-LF-0, S/N 45444); Teledyne Benthos Deck Box (Part #013189 Model...will vary depending on the depth at the site. 92 [Fig. 14] Repeater Nodes We are using 7 Teledyne Benthos ATM-885 Acoustic Telemetry

  7. Evaluation of State-of-the-Art Acoustic Feedback Cancellation Systems for Hearing Aids

    DEFF Research Database (Denmark)

    Guo, Meng; Jensen, Søren Holdt; Jensen, Jesper

    2013-01-01

    This research evaluates four state-of-the-art acoustic feedback cancellation systems in hearing aids in terms of the cancellation performance, sound quality degradation, and computational complexity. The authors compared a traditional full-band system to a system with a prediction error method...

  8. Evaluation of State-of-the-Art Acoustic Feedback Cancellation Systems for Hearing Aids

    DEFF Research Database (Denmark)

    Guo, Meng; Jensen, Søren Holdt; Jensen, Jesper

    2013-01-01

    This research evaluates four state-of-the-art acoustic feedback cancellation systems in hearing aids in terms of the cancellation performance, sound quality degradation, and computational complexity. The authors compared a traditional full-band system to a system with a prediction error method...

  9. Acoustic module of the Acquabona (Italy debris flow monitoring system

    Directory of Open Access Journals (Sweden)

    A. Galgaro

    2005-01-01

    Full Text Available Monitoring of debris flows aimed to the assessment of their physical parameters is very important both for theoretical and practical purposes. Peak discharge and total volume of debris flows are crucial for designing effective countermeasures in many populated mountain areas where losses of lives and property damage could be avoided. This study quantifies the relationship between flow depth, acoustic amplitude of debris flow induced ground vibrations and front velocity in the experimental catchment of Acquabona, Eastern Dolomites, Italy. The analysis of data brought about the results described in the following. Debris flow depth and amplitude of the flow-induced ground vibrations show a good positive correlation. Estimation of both mean front velocity and peak discharge can be simply obtained monitoring the ground vibrations, through geophones installed close to the flow channel; the total volume of debris flow can be so directly estimated from the integral of the ground vibrations using a regression line. The application of acoustic technique to debris flow monitoring seems to be of the outmost relevance in risk reduction policies and in the correct management of the territory. Moreover this estimation is possible in other catchments producing debris flows of similar characteristics by means of their acoustic characterisation through quick and simple field tests (Standard Penetration Tests and seismic refraction surveys.

  10. Channel coding for underwater acoustic single-carrier CDMA communication system

    Science.gov (United States)

    Liu, Lanjun; Zhang, Yonglei; Zhang, Pengcheng; Zhou, Lin; Niu, Jiong

    2017-01-01

    CDMA is an effective multiple access protocol for underwater acoustic networks, and channel coding can effectively reduce the bit error rate (BER) of the underwater acoustic communication system. For the requirements of underwater acoustic mobile networks based on CDMA, an underwater acoustic single-carrier CDMA communication system (UWA/SCCDMA) based on the direct-sequence spread spectrum is proposed, and its channel coding scheme is studied based on convolution, RA, Turbo and LDPC coding respectively. The implementation steps of the Viterbi algorithm of convolutional coding, BP and minimum sum algorithms of RA coding, Log-MAP and SOVA algorithms of Turbo coding, and sum-product algorithm of LDPC coding are given. An UWA/SCCDMA simulation system based on Matlab is designed. Simulation results show that the UWA/SCCDMA based on RA, Turbo and LDPC coding have good performance such that the communication BER is all less than 10-6 in the underwater acoustic channel with low signal to noise ratio (SNR) from -12 dB to -10dB, which is about 2 orders of magnitude lower than that of the convolutional coding. The system based on Turbo coding with Log-MAP algorithm has the best performance.

  11. R&D towards the acoustic positioning system of KM3NeT

    Science.gov (United States)

    Ardid, M.; Bou-Cabo, M.; Camarena, F.; Espinosa, V.; Larosa, G.; Llorens, C. D.; Martínez-Mora, J. A.; KM3NeT Consortium

    2011-01-01

    In this paper we present a possible solution for the acoustic positioning system of KM3NeT, a future very large undersea neutrino telescope. The system consists of an array of budget-priced acoustic transducers that can operate as emitters and receivers in the 20-40 kHz region and withstand the high pressures (up to 500 bar). Versatile associated low-power electronics has been developed, implementing the all-data-to-shore approach. Besides controlling signal transmission and reception, the electronics allows for transducer configuration from shore to benefit from varied on-shore signal processing techniques. We will describe the prototype transceiver and the tests performed to study its specifications, demonstrating that the system fulfils the requirements for the acoustic positioning calibration of KM3NeT.

  12. Perceptual and Acoustic Reliability Estimates for the Speech Disorders Classification System (SDCS)

    Science.gov (United States)

    Shriberg, Lawrence D.; Fourakis, Marios; Hall, Sheryl D.; Karlsson, Heather B.; Lohmeier, Heather L.; McSweeny, Jane L.; Potter, Nancy L.; Scheer-Cohen, Alison R.; Strand, Edythe A.; Tilkens, Christie M.; Wilson, David L.

    2010-01-01

    A companion paper describes three extensions to a classification system for paediatric speech sound disorders termed the Speech Disorders Classification System (SDCS). The SDCS uses perceptual and acoustic data reduction methods to obtain information on a speaker's speech, prosody, and voice. The present paper provides reliability estimates for…

  13. Perceptual and Acoustic Reliability Estimates for the Speech Disorders Classification System (SDCS)

    Science.gov (United States)

    Shriberg, Lawrence D.; Fourakis, Marios; Hall, Sheryl D.; Karlsson, Heather B.; Lohmeier, Heather L.; McSweeny, Jane L.; Potter, Nancy L.; Scheer-Cohen, Alison R.; Strand, Edythe A.; Tilkens, Christie M.; Wilson, David L.

    2010-01-01

    A companion paper describes three extensions to a classification system for paediatric speech sound disorders termed the Speech Disorders Classification System (SDCS). The SDCS uses perceptual and acoustic data reduction methods to obtain information on a speaker's speech, prosody, and voice. The present paper provides reliability estimates for…

  14. On Acoustic Feedback Cancellation Using Probe Noise in Multiple-Microphone and Single-Loudspeaker Systems

    DEFF Research Database (Denmark)

    Guo, Meng; Elmedyb, Thomas Bo; Jensen, Søren Holdt;

    2012-01-01

    of the adaptive estimation is significantly decreased when keeping the steady-state error unchanged. The goal of this work is to derive analytic expressions for the system behavior such as convergence rate and steady-state error for a multiple-microphone and single-loudspeaker audio system, where the acoustic...

  15. An acoustic system for autonomous navigation and tracking of marine fauna

    KAUST Repository

    De la Torre, Pedro

    2014-08-01

    A marine acoustic system for underwater target tracking is described. This system is part of the Integrated Satellite and Acoustic Telemetry (iSAT) project to study marine fauna. It is a microcontroller-based underwater projector and receiver. A narrow-band, passive sonar detection architecture is described from signal generation, through transduction, reception, signal processing and up to tone extraction. Its circuit and operation principles are described. Finally, a comparison between the current energy detection method versus an alternative matched filter approach is included.

  16. A programmable acoustic stimuli and auditory evoked potential measurement system for objective tinnitus diagnosis research.

    Science.gov (United States)

    Ku, Yunseo; Ahn, Joong Woo; Kwon, Chiheon; Suh, Myung-Whan; Lee, Jun Ho; Oh, Seung Ha; Kim, Hee Chan

    2014-01-01

    This paper presents the development of a single platform that records auditory evoked potential synchronized to specific acoustic stimuli of the gap prepulse inhibition method for objective tinnitus diagnosis research. The developed system enables to program various parameters of the generated acoustic stimuli. Moreover, only by simple filter modification, the developed system provides high flexibility to record not only short latency auditory brainstem response but also late latency auditory cortical response. The adaptive weighted averaging algorithm to minimize the time required for the experiment is also introduced. The results show that the proposed algorithm can reduce the number of the averaging repetitions to 70% compared with conventional ensemble averaging method.

  17. A method for Perceptual Assessment of Automotive Audio Systems and Cabin Acoustics

    DEFF Research Database (Denmark)

    Kaplanis, Neofytos; Bech, Søren; Sakari, Tervo;

    2016-01-01

    This paper reports the design and implementation of a method to perceptually assess the acoustical prop- erties of a car cabin and the subsequent sound reproduction properties of automotive audio systems. Here, we combine Spatial Decomposition Method and Rapid Sensory Analysis techniques. The for......This paper reports the design and implementation of a method to perceptually assess the acoustical prop- erties of a car cabin and the subsequent sound reproduction properties of automotive audio systems. Here, we combine Spatial Decomposition Method and Rapid Sensory Analysis techniques...

  18. Energy Source Study Technical Report for Deployable Acoustic Projector System (DAPS)

    Science.gov (United States)

    1988-12-23

    S SPARTON"- AD-A278 879 7097-0001-1192 ENERGY SOURCE STUDY TECHNICAL REPORT FOR DEPLOYABLE ACOUSTIC PROJECTOR SYSTEM (DAPS) Contract N62190-88-M...SUBTITLE 5. FUNDING NUMBERS Energy Source Study Technical Report for Deployable C:N62190-88-q+0755 Acoustic Projector System (DAPS) 6. AUTHOR(S) 7...Rev 2-89) P~IýAIppd by ill* 164 it- IJs IL- 3 Fst’ rPAITON OWiENSE mac vrroNcS r 7097-0001-1192 ENERGY SOURCE STUDY TECHNICAL REPORT I FOR DEPLOYABLE

  19. Distributed acoustic sensing system using an identical weak fiber Bragg grating array

    Science.gov (United States)

    Liu, Sheng; Han, Xinying; Wen, Hongqiao

    2016-10-01

    We propose and experimentally demonstrate a distributed acoustic sensing system using an identical weak fiber Bragg grating array. Phase, frequency and location information of vibration can be demodulated by using a path-match interferometry method. 3×3 coupler demodulation technique is employed to eliminate signal fading in interferometer. Experiments on detecting acoustic wave generated by PZT show that the system is capable of measuring vibrations of up to 1000 Hz over 1.6 km with 2.5m spatial resolution.

  20. Ground penetrating radar and terrestrial laser scanner surveys on deposits of dilute pyroclastic density current deposits: insights for dune bedform genesis

    Science.gov (United States)

    Rémi Dujardin, Jean; Amin Douillet, Guilhem; Abolghasem, Amir; Cordonnier, Benoit; Kueppers, Ulrich; Bano, Maksim; Dingwell, Donald B.

    2014-05-01

    Dune bedforms formed by dilute pyroclastic density currents (PDC) are often described or interpreted as antidunes and chute and pools. However, the interpretation remains essentially speculative and is not well understood. This is largely due to the seeming impossibility of in-situ measurements and experimental scaling, as well as the lack of recent, 3D exposures. Indeed, most dune bedform cross-stratifications from the dilute PDC record outcrop in 2D sections. The 2006 eruption of Tungurahua has produced well-developed bedforms that are well-exposed on the surface of the deposits with easy access. We performed a survey of these deposits combining ground penetrating radar (GPR) profiling with terrestrial laser scanning of the surface. The GPR survey was carried in dense arrays (from 10 to 25 cm spacing between profiles) over ca. 10 m long bedforms. GPR profiles were corrected for topography from photogrammetry data. An in-house software, RadLab (written in matlab), was used for common processing of individual profiles and 2D & 3D topographic migration. Each topography-corrected profile was then loaded into a seismic interpretation software, OpenDtect, for 3D visualization and interpretation. Most bedforms show high lateral stability that is independent of the cross-stratification pattern (that varies between stoss-aggrading bedsets, stoss-erosive bedsets and stoss-depositional lensoidal layers). Anecdotic bedforms have their profiles that evolve laterally (i.e. in a direction perpendicular to the flow direction). Cannibalization of two dune bedforms into a single one on one end of the profile can evolve into growth of a single bedform at the other lateral end. Also, lateral variation in the migration direction occurs, i.e. a single bedform can show upstream aggradation at one lateral end of the bedform, but show downstream migration at the other end. Some bedforms have great variations in their internal structure. Several episodes of growth and erosion can be