OPTIMAL SIGNAL PROCESSING METHODS IN GPR

Directory of Open Access Journals (Sweden)

Saeid Karamzadeh

2014-01-01

Full Text Available In the past three decades, a lot of various applications of Ground Penetrating Radar (GPR took place in real life. There are important challenges of this radar in civil applications and also in military applications. In this paper, the fundamentals of GPR systems will be covered and three important signal processing methods (Wavelet Transform, Matched Filter and Hilbert Huang will be compared to each other in order to get most accurate information about objects which are in subsurface or behind the wall.

A Forward-Looking High-Resolution GPR System

National Research Council Canada - National Science Library

Kositsky, Joel; Milanfar, Peyman

1999-01-01

A high-resolution ground penetrating radar (GPR) system was designed to help define the optimal radar parameters needed for the efficient standoff detection of buried and surface-laid antitank mines...

Contribution of oblateness of the sun to radar sounding according to ...

African Journals Online (AJOL)

The Newtonian theory of radar sounding in the gravitational field of a spherical sun is well known [1]. It is now well established that most of the astronomical bodies including the sun are spheroidal (proplate or oblate) in shape [5,11,12]. The Newtonian mechanics has been used to resolve satisfactorily the radar sounding ...

GPR in Ramboll

Science.gov (United States)

Ringgaard, Jørgen; Wisén, Roger

2014-05-01

The Ramboll Group is a large (10.000 employees worldwide) engineering and consultancy company, with offices in 21 countries. Ramboll has been working with geophysics for about 20 years and at the time of writing there are about 25 geophysicist employed in the group, 20 of these are employed in Ramboll Denmark. Ramboll offers an extensive range of geophysical methods: different types of seismic, borehole wireline logging, electric and electromagnetic surveys, magnetic resonance soundings and well as marine geophysical and hydrographic surveys. The geophysical group at Ramboll operates in different industries comprising: Infrastructure, environmental assessments, mineral exploration, energy and offshore constructions. In the recent years our GPR activities has increased significantly. Today Ramboll Denmark owns three separate GPR systems: One GSSI SIR-3000 with antennas ranging from 16MHz to 2GHz, One Mala geoscience ProEx system with a 100MHz RTA antenna and one 3D-radar Geoscope MKIV system with two DX antennas of different size. The main services are geological mapping with our ProEx system from Malå Geoscience, road mapping with a GSSI system and different shallow mapping with our 3D system from 3D Radar. With our 2D systems we have performed mapping of peat in different places in Norway, mapping of sediments at various places in the Nordic countries and mapping of glacier thickness in Greenland. In this type of investigations we often combine GPR with resistivity imaging (CVES) and refraction seismic to ensure a more reliable interpretation. We have performed occasional utility or UXO surveys where GPR has been used together with EM or magnetic measurements. The mapping on roads with the GSSI system is performed by our RST (Road Surface Testing) department in Malmö, Sweden. The measurements on roads are often combined with laser scanning and photo registration of the surface. Various software have been developed to automatize the interpretation. The RST group

Monitoring underground water leakage pattern by ground penetrating radar (GPR) using 800 MHz antenna frequency

Science.gov (United States)

Amran, T. S. T.; Ismail, M. P.; Ahmad, M. R.; Amin, M. S. M.; Ismail, M. A.; Sani, S.; Masenwat, N. A.; Basri, N. S. M.

2018-01-01

Water is the most treasure natural resources, however, a huge amount of water are lost during its distribution that leads to water leakage problem. The leaks meant the waste of money and created more economic loss to treat and fix the damaged pipe. Researchers and engineers have put tremendous attempts and effort, to solve the water leakage problem especially in water leakage of buried pipeline. An advanced technology of ground penetrating radar (GPR) has been established as one of the non-destructive testing (NDT) method to detect the underground water pipe leaking. This paper focuses on the ability of GPR in water utility field especially on detection of water leaks in the underground pipeline distribution. A series of laboratory experiments were carried out using 800-MHz antenna, where the performance of GPR on detecting underground pipeline and locating water leakage was investigated and validated. A prototype to recreate water-leaking system was constructed using a 4-inch PVC pipe. Different diameter of holes, i.e. ¼ inch, ½ inch, and ¾ inch, were drilled into the pipe to simulate the water leaking. The PVC pipe was buried at the depth of 60 cm into the test bed that was filled with dry sand. 15 litres of water was injected into the PVC pipe. The water leakage patterns in term of radargram data were gathered. The effectiveness of the GPR in locating the underground water leakage was ascertained, after the results were collected and verified.

COST Action TU1208 - Working Group 4 - Combined use of GPR and other NDT methods & GPR applications in geosciences

Science.gov (United States)

Pajewski, Lara; Solla, Mercedes; Fontul, Simona

2017-04-01

This work aims at presenting the main results achieved by Working Group (WG) 4 "Different applications of GPR and other NDT technologies in civil engineering" of the COST (European COoperation in Science and Technology) Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar" (www.GPRadar.eu, www.cost.eu). The main objective of the Action TU1208, started in April 2013 and ending in October 2017, is to exchange and increase scientific-technical knowledge and experience of Ground Penetrating Radar (GPR) techniques in civil engineering, whilst promoting in Europe the effective use of this safe non-destructive technique. The Action involves more than 150 Institutions from 28 COST Countries, a Cooperating State, 6 Near Neighbour Countries and 6 International Partner Countries. WG4 deals with the use of GPR outside from the civil engineering area, namely in archaeological prospecting and cultural heritage diagnostics, agriculture and management of water resources, investigation of polluted industrial sites, non-destructive testing of living tree trunks, planetary exploration, demining, localization of people buried under avalanches and debris, and more. Furthermore, this WG studies the integration of GPR with other Non-Destructive Testing (NDT) methods. The most relevant achievements stemming from WG4 will be presented during the 2017 EGU GA. These are: (i) The collection of thorough information on the state-of-the-art, ongoing studies, problems and future research needs on the topics of interest for this WG; (ii) The performance of a plethora of interesting case studies in important sites all over Europe, including well-known historical places such as Stonehenge (United Kingdom), Carnuntum (Austria), the Wawel Cathedral (Cracow, Poland), the Tholos Tomb of Acharnon (Athens, Greece), the Łazienki Royal Palace (Warsaw, Poland), and more; (iii) WG4 contributed to the TU1208 Education Pack, an open educational package conceived to teach GPR in University

Sounding Cratonic Fill in Small Buried Craters Using Ground Penetrating Radar: Analog Study to the Martian Case

OpenAIRE

Heggy , Essam; Paillou , Philippe

2006-01-01

We report results from a 270 MHz GPR survey performed on a recently discovered impact field in the southwestern Egyptian desert. The investigation suggests the ability of radar techniques to detect small-buried craters and probe their filling

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

Detection of underground water distribution piping system and leakages using ground penetrating radar (GPR)

Science.gov (United States)

Amran, Tengku Sarah Tengku; Ismail, Mohamad Pauzi; Ahmad, Mohamad Ridzuan; Amin, Mohamad Syafiq Mohd; Sani, Suhairy; Masenwat, Noor Azreen; Ismail, Mohd Azmi; Hamid, Shu-Hazri Abdul

2017-01-01

A water pipe is any pipe or tubes designed to transport and deliver water or treated drinking with appropriate quality, quantity and pressure to consumers. The varieties include large diameter main pipes, which supply entire towns, smaller branch lines that supply a street or group of buildings or small diameter pipes located within individual buildings. This distribution system (underground) is used to describe collectively the facilities used to supply water from its source to the point of usage. Therefore, a leaking in the underground water distribution piping system increases the likelihood of safe water leaving the source or treatment facility becoming contaminated before reaching the consumer. Most importantly, leaking can result in wastage of water which is precious natural resources. Furthermore, they create substantial damage to the transportation system and structure within urban and suburban environments. This paper presents a study on the possibility of using ground penetrating radar (GPR) with frequency of 1GHz to detect pipes and leakages in underground water distribution piping system. Series of laboratory experiment was designed to investigate the capability and efficiency of GPR in detecting underground pipes (metal and PVC) and water leakages. The data was divided into two parts: 1. detecting/locating underground water pipe, 2. detecting leakage of underground water pipe. Despite its simplicity, the attained data is proved to generate a satisfactory result indicating GPR is capable and efficient, in which it is able to detect the underground pipe and presence of leak of the underground pipe.

Crevasse detection with GPR across the Ross Ice Shelf, Antarctica

Science.gov (United States)

Delaney, A.; Arcone, S.

2005-12-01

We have used 400-MHz ground penetrating radar (GPR) to detect crevasses within a shear zone on the Ross Ice Shelf, Antarctica, to support traverse operations. The transducer was attached to a 6.5-m boom and pushed ahead of an enclosed tracked vehicle. Profile speeds of 4.8-11.3 km / hr allowed real-time crevasse image display and a quick, safe stop when required. Thirty-two crevasses were located with radar along the 4.8 km crossing. Generally, crevasse radar images were characterized by dipping reflections above the voids, high-amplitude reflections originating from ice layers at the base of the snow-bridges, and slanting, diffracting reflections from near-vertical crevasse walls. New cracks and narrow crevasses (back-filling with bulldozed snow, afforded an opportunity to ground-truth GPR interpretations by comparing void size and snow-bridge geometry with the radar images. While second and third season radar profiles collected along the identical flagged route confirmed stability of the filled crevasses, those profiles also identified several new cracks opened by ice extension. Our experiments demonstrate capability of high-frequency GPR in a cold-snow environment for both defining snow layers and locating voids.

The application of GPR in survey of Yongshan coalmine bridge

International Nuclear Information System (INIS)

Liao Yuhua; Deng Juzhi

2007-01-01

Ground penetrating radar (GPR) is an effective shoallow exploration method which uses the reflection of high frequency electromagnetism pulse wave to detect the object and geologic phenomena underground. With the development of electron and computer technique, the application domain of this method is keeping enlarge. Based on the working principle of GPR, this paper discussed the good effect of GPR to pier prospecting in Yongshan coal mines. Some matters that should be attentive are posed while using GPR. (authors)

GPR Imaging for Deeply Buried Objects: A Comparative Study Based on FDTD Models and Field Experiments

Science.gov (United States)

Tilley, roger; Dowla, Farid; Nekoogar, Faranak; Sadjadpour, Hamid

2012-01-01

Conventional use of Ground Penetrating Radar (GPR) is hampered by variations in background environmental conditions, such as water content in soil, resulting in poor repeatability of results over long periods of time when the radar pulse characteristics are kept the same. Target objects types might include voids, tunnels, unexploded ordinance, etc. The long-term objective of this work is to develop methods that would extend the use of GPR under various environmental and soil conditions provided an optimal set of radar parameters (such as frequency, bandwidth, and sensor configuration) are adaptively employed based on the ground conditions. Towards that objective, developing Finite Difference Time Domain (FDTD) GPR models, verified by experimental results, would allow us to develop analytical and experimental techniques to control radar parameters to obtain consistent GPR images with changing ground conditions. Reported here is an attempt at developing 20 and 3D FDTD models of buried targets verified by two different radar systems capable of operating over different soil conditions. Experimental radar data employed were from a custom designed high-frequency (200 MHz) multi-static sensor platform capable of producing 3-D images, and longer wavelength (25 MHz) COTS radar (Pulse EKKO 100) capable of producing 2-D images. Our results indicate different types of radar can produce consistent images.

Measuring snow water equivalent from common-offset GPR records through migration velocity analysis

Science.gov (United States)

St. Clair, James; Holbrook, W. Steven

2017-12-01

Many mountainous regions depend on seasonal snowfall for their water resources. Current methods of predicting the availability of water resources rely on long-term relationships between stream discharge and snowpack monitoring at isolated locations, which are less reliable during abnormal snow years. Ground-penetrating radar (GPR) has been shown to be an effective tool for measuring snow water equivalent (SWE) because of the close relationship between snow density and radar velocity. However, the standard methods of measuring radar velocity can be time-consuming. Here we apply a migration focusing method originally developed for extracting velocity information from diffracted energy observed in zero-offset seismic sections to the problem of estimating radar velocities in seasonal snow from common-offset GPR data. Diffractions are isolated by plane-wave-destruction (PWD) filtering and the optimal migration velocity is chosen based on the varimax norm of the migrated image. We then use the radar velocity to estimate snow density, depth, and SWE. The GPR-derived SWE estimates are within 6 % of manual SWE measurements when the GPR antenna is coupled to the snow surface and 3-21 % of the manual measurements when the antenna is mounted on the front of a snowmobile ˜ 0.5 m above the snow surface.

Surface return direction-of-arrival analysis for radar ice sounding surface clutter suppression

DEFF Research Database (Denmark)

Nielsen, Ulrik; Dall, Jørgen

2015-01-01

Airborne radar ice sounding is challenged by surface clutter masking the depth signal of interest. Surface clutter may even be prohibitive for potential space-based ice sounding radars. To some extent the radar antenna suppresses the surface clutter, and a multi-phase-center antenna in combination...... with coherent signal processing techniques can improve the suppression, in particular if the direction of arrival (DOA) of the clutter signal is estimated accurately. This paper deals with data-driven DOA estimation. By using P-band data from the ice shelf in Antarctica it is demonstrated that a varying...

Inertial and GPS data integration for positioning and tracking of GPR

Science.gov (United States)

Chicarella, Simone; D'Alvano, Alessandro; Ferrara, Vincenzo; Frezza, Fabrizio; Pajewski, Lara

2015-04-01

Nowadays many applications and studies use a Global Positioning System (GPS) to integrate Ground-Penetrating Radar (GPR) data [1-2]. The aim is the production of detailed detection maps that are geo-referenced and superimposable on geographic maps themes. GPS provides data to determine static positioning, and to track the mobile detection system path on the land. A low-cost standard GPS, like GPS-622R by RF Solutions Ltd, allows accuracy around 2.5 m CEP (Circular Error Probability), and a maximum update rate of 10 Hz. These accuracy and update rate are satisfying values when we evaluate positioning datum, but they are unsuitable for precision tracking of a speedy-mobile GPR system. In order to determine the relative displacements with respect to an initial position on the territory, an Inertial Measurement Unit (IMU) can be used. Some inertial-system applications for GPR tracking have been presented in recent studies [3-4]. The integration of both GPS and IMU systems is the aim of our work, in order to increase GPR applicability, e.g. the case of a GPR mounted on an unmanned aerial vehicle for the detection of people buried under avalanches [5]. In this work, we will present the design, realization and experimental characterization of our electronic board that includes GPS-622R and AltIMU-10 v3 by Pololu. The latter comprises an inertial-measurement unit and an altimeter. In particular, the IMU adopts L3GD20 gyro and LSM303D accelerometer and magnetometer; the digital barometer LPS331AP provides data for altitude evaluation. The prototype of our system for GPR positioning and tracking is based on an Arduino microcontroller board. Acknowledgement This work benefited from networking activities carried out within the EU funded COST Action TU1208 'Civil Engineering Applications of Ground Penetrating Radar. ' References [1] M. Solla, X. Núñez-Nieto, M. Varela-González, J. Martínez-Sánchez, and P. Arias, 'GPR for Road Inspection: georeferencing and efficient

Fundamentals of ground penetrating radar in environmental and engineering applications

Energy Technology Data Exchange (ETDEWEB)

Casas, A.; Pinto, V.; Rivero, L. [Barcelona Univ., Barcelona (Spain). Faculty of Geology, Dept. of Geochemistry, Petrology and Geological Prospecting

2000-12-01

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.

Fundamentals of ground penetrating radar in environmental and engineering applications

International Nuclear Information System (INIS)

Casas, A.; Pinto, V.; Rivero, L.

2000-01-01

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

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.

Online Dictionary Learning Aided Target Recognition In Cognitive GPR

OpenAIRE

Giovanneschi, Fabio; Mishra, Kumar Vijay; Gonzalez-Huici, Maria Antonia; Eldar, Yonina C.; Ender, Joachim H. G.

2017-01-01

Sparse decomposition of ground penetration radar (GPR) signals facilitates the use of compressed sensing techniques for faster data acquisition and enhanced feature extraction for target classification. In this paper, we investigate the application of an online dictionary learning (ODL) technique in the context of GPR to bring down the learning time as well as improve identification of abandoned anti-personnel landmines. Our experimental results using real data from an L-band GPR for PMN/PMA2...

Joint application of Geoelectrical Resistivity and Ground Penetrating Radar techniques for the study of hyper-saturated zones. Case study in Egypt

Directory of Open Access Journals (Sweden)

Hany S. Mesbah

2017-06-01

Full Text Available 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.

Coherent Surface Clutter Suppression Techniques with Topography Estimation for Multi-Phase-Center Radar Ice Sounding

DEFF Research Database (Denmark)

Nielsen, Ulrik; Dall, Jørgen; Kristensen, Steen Savstrup

2012-01-01

Radar ice sounding enables measurement of the thickness and internal structures of the large ice sheets on Earth. Surface clutter masking the signal of interest is a major obstacle in ice sounding. Algorithms for surface clutter suppression based on multi-phase-center radars are presented. These ...

Forestry applications of ground-penetrating radar

Energy Technology Data Exchange (ETDEWEB)

Lorenzo, H.; Perez-Gracia, V.; Novo, A.; Armesto, J.

2010-07-01

Ground-penetrating radar (GPR) is a geophysical and close-range remote sensing technique based on the use of radar pulses to obtain cross-section images of underground features. This method is characterized by the transmission of an electromagnetic short length pulse (1-2 ns), presenting a centre frequency ranging from 10 MHz to 2.5 GHz. The principles of GPR operation are based on the ability of low frequency radar waves to penetrate into a non-conductive medium, usually subsoil, but also walls, concrete or wood. Those waves are detected after suffering a reflection in electromagnetic discontinuities of the propagation medium. Therefore, this is a suitable method to study changes in those physical properties, and also to characterize different mediums and the reflective targets providing information about their physical properties. The aim of this work is to describe and demonstrate different applications of GPR in forestry, showing the obtained results together with their interpretation. Firstly, in this paper, it is illustrated how GPR is able to map shallow bedrock, subsoil stratigraphy and also to estimate shallow water table depth. Secondly, different tree trunks as well as dry timber are analyzed, evaluating the different radar data obtained in each particular case, and observing differences in their electromagnetic properties related to the GPR response. Finally, several measurements were taken in order to analyze the use of GPR to detect tree root systems using polarimetric techniques, being possible to detect medium and big size roots, together with groups of small roots. (Author) 39 refs.

GPR Imaging of Prehistoric Animal Bone-beds

Science.gov (United States)

Schneider, Blair Benson

This research investigates the detection capabilities of Ground-penetrating radar for imaging prehistoric animal bone-beds. The first step of this investigation was to determine the dielectric properties of modern animal bone as a proxy for applying non-invasive ground-penetrating radar (GPR) for detecting prehistoric animal remains. Over 90 thin section samples were cut from four different modern faunal skeleton remains: bison, cow, deer, and elk. One sample of prehistoric mammoth core was also analyzed. Sample dielectric properties (relative permittivity, loss factor, and loss-tangent values) were measured with an impedance analyzer over frequencies ranging from 10 MHz to 1 GHz. The results reveal statistically significant dielectric-property differences among different animal fauna, as well as variation as a function of frequency. The measured sample permittivity values were then compared to modeled sample permittivity values using common dielectric-mixing models. The dielectric mixing models were used to report out new reported values of dry bone mineral of 3-5 in the frequency range of 10 MHz to 1 GHz. The second half of this research collected controlled GPR experiments over a sandbox containing buried bison bone elements to evaluate GPR detection capabilities of buried animal bone. The results of the controlled GPR sandbox tests were then compared to numerical models in order to predict the ability of GPR to detect buried animal bone given a variety of different depositional factors, the size and orientation of the bone target and the degree of bone weathering. The radar profiles show that GPR is an effective method for imaging the horizontal and vertical extent of buried animal bone. However, increased bone weathering and increased bone dip were both found to affect GPR reflection signal strength. Finally, the controlled sandbox experiments were also utilized to investigate the impact of survey design for imaging buried animal bone. In particular, the

Measuring snow water equivalent from common-offset GPR records through migration velocity analysis

Directory of Open Access Journals (Sweden)

J. St. Clair

2017-12-01

Full Text Available Many mountainous regions depend on seasonal snowfall for their water resources. Current methods of predicting the availability of water resources rely on long-term relationships between stream discharge and snowpack monitoring at isolated locations, which are less reliable during abnormal snow years. Ground-penetrating radar (GPR has been shown to be an effective tool for measuring snow water equivalent (SWE because of the close relationship between snow density and radar velocity. However, the standard methods of measuring radar velocity can be time-consuming. Here we apply a migration focusing method originally developed for extracting velocity information from diffracted energy observed in zero-offset seismic sections to the problem of estimating radar velocities in seasonal snow from common-offset GPR data. Diffractions are isolated by plane-wave-destruction (PWD filtering and the optimal migration velocity is chosen based on the varimax norm of the migrated image. We then use the radar velocity to estimate snow density, depth, and SWE. The GPR-derived SWE estimates are within 6 % of manual SWE measurements when the GPR antenna is coupled to the snow surface and 3–21 % of the manual measurements when the antenna is mounted on the front of a snowmobile  ∼  0.5 m above the snow surface.

Use of ground-penetrating radar techniques in archaeological investigations

Science.gov (United States)

Doolittle, James A.; Miller, W. Frank

1991-01-01

Ground-penetrating radar (GPR) techniques are increasingly being used to aid reconnaissance and pre-excavation surveys at many archaeological sites. As a 'remote sensing' tool, GPR provides a high resolution graphic profile of the subsurface. Radar profiles are used to detect, identify, and locate buried artifacts. Ground-penetrating radar provides a rapid, cost effective, and nondestructive method for identification and location analyses. The GPR can be used to facilitate excavation strategies, provide greater areal coverage per unit time and cost, minimize the number of unsuccessful exploratory excavations, and reduce unnecessary or unproductive expenditures of time and effort.

Exploring inner structure of Titan's dunes from Cassini Radar observations

Science.gov (United States)

Sharma, P.; Heggy, E.; Farr, T. G.

2013-12-01

Linear dunes discovered in the equatorial regions of Titan by the Cassini-Huygens mission are morphologically very similar to many terrestrial linear dune fields. These features have been compared with terrestrial longitudinal dune fields like the ones in Namib desert in western Africa. This comparison is based on the overall parallel orientation of Titan's dunes to the predominant wind direction on Titan, their superposition on other geomorphological features and the way they wrap around topographic obstacles. Studying the internal layering of dunes has strong implications in understanding the hypothesis for their origin and evolution. In Titan's case, although the morphology of the dunes has been studied from Cassini Synthetic Aperture Radar (SAR) images, it has not been possible to investigate their internal structure in detail as of yet. Since no radar sounding data is available for studying Titan's subsurface yet, we have developed another technique to examine the inner layering of the dunes. In this study, we utilize multiple complementary radar datasets, including radar imaging data for Titan's and Earth's dunes and Ground Penetrating Radar (GPR)/radar sounding data for terrestrial dunes. Based on dielectric mixing models, we suggest that the Cassini Ku-band microwaves should be able to penetrate up to ~ 3 m through Titan's dunes, indicating that the returned radar backscatter signal would include contributions from both surface and shallow subsurface echoes. This implies that the shallow subsurface properties can be retrieved from the observed radar backscatter (σ0). In our analysis, the variation of the radar backscatter as a function of dune height is used to provide an insight into the layering in Titan's dunes. We compare the variation of radar backscatter with elevation over individual dunes on Titan and analogous terrestrial dunes in three sites (Great Sand Sea, Siwa dunes and Qattaniya dunes) in the Egyptian Sahara. We observe a strong, positive

GPR utilization in artificial freezing engineering

International Nuclear Information System (INIS)

Song, Lei; Yang, Weihao; Huang, Jiahui; Li, Haipeng; Zhang, Xiaojun

2013-01-01

To utilize ground penetrating radar (GPR) in artificial freezing engineering (AFE), the electromagnetic parameters (EMP) of frozen soil were measured using a vector network analyser, which showed that the dielectric permittivity and electric conductivity change abruptly at the boundary between the frozen and the non-frozen soil. Then similarity criteria of GPR model experiments were deduced, and GPR laboratory model experiments and field explorations of AFE were carried out. It was found that for AFE, the GPR travel time and profile characters of anomalies in model experiments were similar to those in field explorations, while the amplitude of GPR signals in laboratory model experiments were much stronger than those in field explorations. Numerical simulations were also implemented to analyse the relationship between model experiments and field explorations, which further told us why we could easily find the targets by GPR in the laboratory but not in field explorations. The outputs showed that GPR could be used to detect the thickness of the frozen wall and to find unfrozen soil defects, even though the amplitude of the reflective signals were much weaker than those of laboratory experiments. The research findings have an important theoretical value for AFE and permafrost region engineering, and the deduced GPR similarity criteria could be widely used in other GPR model experiments. (paper)

Jupiter Trojan's Shallow Subsurface: Direct Observation By Radar Sounding

Science.gov (United States)

Herique, A.; Plettemeier, D.; Beck, P.; Michel, P.; Kumamoto, A.; Kofman, W. W.

2017-12-01

Most of the Jupiter's Trojan are classified as spectral type P or D from visible and near-IR observations. Still, major question remain regarding theire origin and geological evolution: What ices are present in their interior, and in what amount? What is the abundance and the nature of the organic fraction? Did they experience some level of differentiation powered by 26Al? Answering theses question is the goal of the Solar-Power Sail JAXA mission [1, 2]. This mission plans to study the surface by remote sensing in the optical in IR domain. This probe will carry a large-sized lander with a drill to sample the constitutive material at meter depth in order to complement physical and chemical properties measured by on-board instruments. The sample return is an option under study.Radar sounding of the shallow subsurface would be envisaged in complement to this payload. Sounding radar could provide the structure of the first tens of meters of the Trojan surface. It will allow identifying layering, ice lens, and embedded block. It also will enable to reconnect the surface with the deep interior in order to identify exogenous / pristine material. For the surface package, the drilling and the sample return, radar sounding is a unique opportunity to support the selection of the landing site and to provide the greater geological context of the samples that will be returned to Earth.In this paper, we will detail the objective of this instrument and then we will outline the proposed instrument, which is inheriting from the radar developed for the AIDA/AIM mission.[1] Mori, O. et al., Science experiments on a Jupiter Trojan Asteroid in the solar powerd sail mission. LPSC 2016 - 1822.[2] Okada, T. et al., Science and Exploration of a Jupiter Trojan Asteroid in the solar-power sail mission. LPSC 2017 - 1828.

Assessment of highway pavements using GPR

Science.gov (United States)

Plati, Christina; Loizos, Andreas

2015-04-01

Highway infrastructure is a prerequisite for a functioning economy and social life. Highways, often prone to congestion and disruption, are one of the aspects of a modern transport network that require maximum efficiency if an integrated transport network, and sustainable mobility, is to be achieved. Assessing the condition of highway structures, to plan subsequent maintenance, is essential to allow the long-term functioning of a road network. Optimizing the methods used for such assessment will lead to better information being obtained about the road and underlying ground conditions. The condition of highway structures will be affected by a number of factors, including the properties of the highway pavement, the supporting sub-base and the subgrade (natural ground), and the ability to obtain good information about the entire road structure, from pavement to subgrade, allows appropriate maintenance programs to be planned. The maintenance of highway pavements causes considerable cost and in many cases obstruction to traffic flow. In this situation, methods that provide information on the present condition of pavement structure non-destructively and economically are of great interest. It has been shown that Ground-Penetrating-Radar (GPR), which is a Non Destructive Technique (NDT), can deliver information that is useful for the planning of pavement maintenance activities. More specifically GPR is used by pavement engineers in order to determine physical properties and characteristics of the pavement structure, information that is valuable for the assessment of pavement condition. This work gives an overview on the practical application of GPR using examples from highway asphalt pavements monitoring. The presented individual applications of GPR pavement diagnostics concern structure homogeneity, thickness of pavement layers, dielectric properties of asphalt materials etc. It is worthwhile mentioning that a number of applications are standard procedures, either

Pipe-flange detection with GPR

International Nuclear Information System (INIS)

Bonomo, Néstor; De la Vega, Matías; Martinelli, Patricia; Osella, Ana

2011-01-01

This paper describes an application of the ground penetrating radar (GPR) method for detecting pipe flanges. A case history is described in which GPR was successfully used to locate pipe flanges along an 8 km metal pipeline, using a fixed-offset methodology, from the ground surface. Summaries of numerical simulations and in situ tests, performed before the definitive prospecting to evaluate the feasibility of detection, are included. Typical GPR signals are analysed and several examples shown. Constant-time sections of data volumes and migration are evaluated with the goal of distinguishing flange signals from rock signals in unclear situations. The applied methodology was effective for detecting the pipe flanges in relatively short times, with accuracies below 10 cm in the horizontal direction and 20 cm in the vertical direction

Surface-based GPR underestimates below-stump root biomass

Science.gov (United States)

John R. Butnor; Lisa J. Samuelson; Thomas A. Stokes; Kurt H. Johnsen; Peter H. Anderson; Carlos A. Gonzalez-Benecke

2016-01-01

Aims While lateral root mass is readily detectable with ground penetrating radar (GPR), the roots beneath a tree (below-stump) and overlapping lateral roots near large trees are problematic for surface-based antennas operated in reflection mode. We sought to determine if tree size (DBH) effects GPR root detection proximal to longleaf pine (Pinus palustris Mill) and if...

Progress in quantitative GPR development at CNDE

Science.gov (United States)

Eisenmann, David; Margetan, F. J.; Chiou, C.-P.; Roberts, Ron; Wendt, Scott

2014-02-01

Ground penetrating radar (GPR) uses electromagnetic (EM) radiation pulses to locate and map embedded objects. Commercial GPR instruments are generally geared toward producing images showing the location and extent of buried objects, and often do not make full use of available absolute amplitude information. At the Center for Nondestructive Evaluation (CNDE) at Iowa State University efforts are underway to develop a more quantitative approach to GPR inspections in which absolute amplitudes and spectra of measured signals play a key role. Guided by analogous work in ultrasonic inspection, there are three main thrusts to the effort. These focus, respectively, on the development of tools for: (1) analyzing raw GPR data; (2) measuring the EM properties of soils and other embedding media; and (3) simulating GPR inspections. This paper reviews progress in each category. The ultimate goal of the work is to develop model-based simulation tools that can be used assess the usefulness of GPR for a given inspection scenario, to optimize inspection choices, and to determine inspection reliability.

Progress in quantitative GPR development at CNDE

International Nuclear Information System (INIS)

Eisenmann, David; Margetan, F. J.; Chiou, C.-P.; Roberts, Ron; Wendt, Scott

2014-01-01

Ground penetrating radar (GPR) uses electromagnetic (EM) radiation pulses to locate and map embedded objects. Commercial GPR instruments are generally geared toward producing images showing the location and extent of buried objects, and often do not make full use of available absolute amplitude information. At the Center for Nondestructive Evaluation (CNDE) at Iowa State University efforts are underway to develop a more quantitative approach to GPR inspections in which absolute amplitudes and spectra of measured signals play a key role. Guided by analogous work in ultrasonic inspection, there are three main thrusts to the effort. These focus, respectively, on the development of tools for: (1) analyzing raw GPR data; (2) measuring the EM properties of soils and other embedding media; and (3) simulating GPR inspections. This paper reviews progress in each category. The ultimate goal of the work is to develop model-based simulation tools that can be used assess the usefulness of GPR for a given inspection scenario, to optimize inspection choices, and to determine inspection reliability

Progress in quantitative GPR development at CNDE

Energy Technology Data Exchange (ETDEWEB)

Eisenmann, David; Margetan, F. J.; Chiou, C.-P.; Roberts, Ron; Wendt, Scott [Center for Nondestructive Evaluation, Iowa State University, 1915 Scholl Road, Ames, IA 50011-3042 (United States)

2014-02-18

Ground penetrating radar (GPR) uses electromagnetic (EM) radiation pulses to locate and map embedded objects. Commercial GPR instruments are generally geared toward producing images showing the location and extent of buried objects, and often do not make full use of available absolute amplitude information. At the Center for Nondestructive Evaluation (CNDE) at Iowa State University efforts are underway to develop a more quantitative approach to GPR inspections in which absolute amplitudes and spectra of measured signals play a key role. Guided by analogous work in ultrasonic inspection, there are three main thrusts to the effort. These focus, respectively, on the development of tools for: (1) analyzing raw GPR data; (2) measuring the EM properties of soils and other embedding media; and (3) simulating GPR inspections. This paper reviews progress in each category. The ultimate goal of the work is to develop model-based simulation tools that can be used assess the usefulness of GPR for a given inspection scenario, to optimize inspection choices, and to determine inspection reliability.

3D FDTD modelling of GPR: the effects of antenna polarisation on gpr signals from nonmetal pipes

International Nuclear Information System (INIS)

Amiruddin Shaari

2003-01-01

A 3D finite-difference time domain (FDTD) modelling of ground penetrating radar (GPR) has been carried out in order to determine the effectiveness of the method when it is used in a ground survey for metal and nonmetal pipes. In particular, the effects of the relative orientation between the antenna polarisation and pipe length and the dielectric contrast between ground soil and pipes on the GPR signal strength are investigated. The results show that the parallel antenna-target is the preferred orientation for metal pipes while the normal or orthogonal arrangement is the preferred one for the nonmetal pipes. The dielectric contrast between medium and target also seems to affect the strength the GPR signals from the nines. (Author)

An experiment on a sand-dune environment in Southern Venetian coast based on GPR, VES and documentary evidence

Energy Technology Data Exchange (ETDEWEB)

Galgaro, A.; Finzi, E. [Padua Univ., Padua (Italy). Dipt. di Geologia, Paleontologia e Geofisica; Tosi, L. [Consiglio Nazionale delle Ricerche, Venice (Italy). Ist. per l Studio della Dinamica delle Grandi Masse

2000-04-01

The internal structures of some surviving sand dunes and the ancient shore-lines along the coast south of Venice (Italy) have been investigated integrating ground probing radar (GPR) profiles, vertical electrical soundings (VES) and water conductivity measurements in some boreholes. The GPR penetration depth has been limited (4-5 m, using a 400 MHz antenna) by the high conductivity of salt water saturating pores of the shallow sediments. On the other hand, the excellent spatial resolution of the radar survey provided an estimate of internal dune bedding features, such as cross lamination and forwarding ancient covered coast-lines dated in the Thirties. The interpretation of the data, in particular along one line 360 m long intercepting a sizeable sand-dune bank, seems to offer clues to the evolutional history of the coast line and the depth of transition from fresh-water to brackish-salt water. The water table was detected with electrical measurements and direct observations in boreholes, whereas the transition between fresh and salt water was pointed out indirectly by the high energy absorption and total back-reflection of the electromagnetic waves, encountered at this boundary, and directly by the strong decrease in VES resistivity values.

COST Action TU1208 - Working Group 2 - GPR surveying of pavements, bridges, tunnels and buildings; underground utility and void sensing

Science.gov (United States)

Pajewski, Lara; Benedetto, Andrea; Derobert, Xavier; Fontul, Simona; Govedarica, Miro; Gregoire, Colette; Loizos, Andreas; Perez-Gracia, Vega; Plati, Christina; Ristic, Aleksandar; Tosti, Fabio; Van Geem, Carl

2017-04-01

This work aims at presenting the main results achieved by Working Group (WG) 2 "GPR surveying of pavements, bridges, tunnels and buildings; underground utility and void sensing" of the COST (European COoperation in Science and Technology) Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar" (www.GPRadar.eu, www.cost.eu). The principal goal of the Action, started in April 2013 and ending in October 2017, is to exchange and increase scientific-technical knowledge and experience of Ground Penetrating Radar (GPR) 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 WG2 include: 1. The state of the art on the use of GPR in civil engineering was composed and open issues were identified. The few existing international/national guidelines/protocols for GPR inspection in civil engineering were reviewed and discussed. Academic end-users, private companies and stakeholders presented their point of view and needs. 2. Guidelines for investigating flexible pavement by using GPR were prepared, with particular regard to layer-thickness assessment, moisture-content sensing, pavement-damage detection and classification, and other main GPR-based investigations in pavement engineering. 3. Guidelines for GPR sensing and mapping of underground utilities and voids were prepared, with a main focus on urban areas. 4. Guidelines for GPR assessment of concrete structures, with particular regard to inspections in bridges and tunnels, were prepared. 5. A report was composed, including a series of practical suggestions and very useful information to guide GPR users during building inspection. 6. WG2 Members carried out a plethora of case studies where GPR was used to survey roads, highways, airport runways, car

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.

Mine detection using SF-GPR: A signal processing approach for resolution enhancement and clutter reduction

DEFF Research Database (Denmark)

Karlsen, Brian; Jakobsen, Kaj Bjarne; Larsen, Jan

2001-01-01

Proper clutter reduction is essential for Ground Penetrating Radar data since low signal-to-clutter ratio prevent correct detection of mine objects. A signal processing approach for resolution enhancement and clutter reduction used on Stepped-Frequency Ground Penetrating Radar (SF-GPR) data is pr....... The clutter reduction method is based on basis function decomposition of the SF-GPR time-series from which the clutter and the signal are separated....

Modern Radar Techniques for Geophysical Applications: Two Examples

Science.gov (United States)

Arokiasamy, B. J.; Bianchi, C.; Sciacca, U.; Tutone, G.; Zirizzotti, A.; Zuccheretti, E.

2005-01-01

The last decade of the evolution of radar was heavily influenced by the rapid increase in the information processing capabilities. Advances in solid state radio HF devices, digital technology, computing architectures and software offered the designers to develop very efficient radars. In designing modern radars the emphasis goes towards the simplification of the system hardware, reduction of overall power, which is compensated by coding and real time signal processing techniques. Radars are commonly employed in geophysical radio soundings like probing the ionosphere; stratosphere-mesosphere measurement, weather forecast, GPR and radio-glaciology etc. In the laboratorio di Geofisica Ambientale of the Istituto Nazionale di Geofisica e Vulcanologia (INGV), Rome, Italy, we developed two pulse compression radars. The first is a HF radar called AIS-INGV; Advanced Ionospheric Sounder designed both for the purpose of research and for routine service of the HF radio wave propagation forecast. The second is a VHF radar called GLACIORADAR, which will be substituting the high power envelope radar used by the Italian Glaciological group. This will be employed in studying the sub glacial structures of Antarctica, giving information about layering, the bed rock and sub glacial lakes if present. These are low power radars, which heavily rely on advanced hardware and powerful real time signal processing. Additional information is included in the original extended abstract.

A comparison of GPR performance at various frequencies - a guide to improved survey design

CSIR Research Space (South Africa)

Kgarume, Thabang E

2015-09-01

Full Text Available This paper aims to demonstrate, through practical examples and numerical modelling, the trade-off between range and resolution in ground penetrating radar (GPR) prospecting. GPR surveys can easily fail when the target and host rock properties...

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....

Modeling of GPR Clutter Caused by Soil Heterogeneity

Directory of Open Access Journals (Sweden)

Kazunori Takahashi

2012-01-01

Full Text Available In small-scale measurements, ground-penetrating radar (GPR often uses a higher frequency to detect a small object or structural changes in the ground. GPR becomes more sensitive to the natural heterogeneity of the soil when a higher frequency is used. Soil heterogeneity scatters electromagnetic waves, and the scattered waves are in part observed as unwanted reflections that are often referred to as clutter. Data containing a great amount of clutter are difficult to analyze and interpret because clutter disturbs reflections from objects of interest. Therefore, modeling GPR clutter is useful to assess the effectiveness of GPR measurements. In this paper, the development of such a technique is discussed. This modeling technique requires the permittivity distribution of soil (or its geostatistical properties and gives a nominal value of clutter power. The paper demonstrates the technique with the comparison to the data from a GPR time-lapse measurement. The proposed technique is discussed in regard to its applicability and limitations based on the results.

Quantitative analysis of ground penetrating radar data in the Mu Us Sandland

Science.gov (United States)

Fu, Tianyang; Tan, Lihua; Wu, Yongqiu; Wen, Yanglei; Li, Dawei; Duan, Jinlong

2018-06-01

Ground penetrating radar (GPR), which can reveal the sedimentary structure and development process of dunes, is widely used to evaluate aeolian landforms. The interpretations for GPR profiles are mostly based on qualitative descriptions of geometric features of the radar reflections. This research quantitatively analyzed the waveform parameter characteristics of different radar units by extracting the amplitude and time interval parameters of GPR data in the Mu Us Sandland in China, and then identified and interpreted different sedimentary structures. The results showed that different types of radar units had specific waveform parameter characteristics. The main waveform parameter characteristics of sand dune radar facies and sandstone radar facies included low amplitudes and wide ranges of time intervals, ranging from 0 to 0.25 and 4 to 33 ns respectively, and the mean amplitudes changed gradually with time intervals. The amplitude distribution curves of various sand dune radar facies were similar as unimodal distributions. The radar surfaces showed high amplitudes with time intervals concentrated in high-value areas, ranging from 0.08 to 0.61 and 9 to 34 ns respectively, and the mean amplitudes changed drastically with time intervals. The amplitude and time interval values of lacustrine radar facies were between that of sand dune radar facies and radar surfaces, ranging from 0.08 to 0.29 and 11 to 30 ns respectively, and the mean amplitude and time interval curve was approximately trapezoidal. The quantitative extraction and analysis of GPR reflections could help distinguish various radar units and provide evidence for identifying sedimentary structure in aeolian landforms.

Double-Sided Sliding-Paraboloid (DSSP): A new tool for preprocessing GPR data

Science.gov (United States)

Rashed, Mohamed; Rashed, Essam A.

2017-05-01

Background noise in Ground Penetrating Radar (GPR) data is a nagging problem that degrades the quality of GPR images and increases their ambiguity. There are several methods adopting different strategies to remove background noise. In this study, we present the Double-Sided Sliding-Paraboloid (DSSP) as a new background removal technique. Experiments conducted on field GPR data show that the proposed DSSP technique has several advantages over existing background removal techniques. DSSP removes background noise more efficiently while preserving first arrivals and other strong horizontal reflections. Moreover, DSSP introduces no artifacts to GPR data and corrects data for DC-shift and wow noise.

Monitoring soil moisture dynamics via ground-penetrating radar survey of agriculture fields after irrigation

Science.gov (United States)

Muro, G.

2015-12-01

It is possible to examine the quality of ground-penetrating radar (GPR) as a measure of soil moisture content in the shallow vadose zone, where roots are most abundant and water conservation best management practices are critical in active agricultural fields. By analyzing temporal samplings of 100 Mhz reflection profiles and common-midpoint (CMP) soundings over a full growing season, the variability of vertical soil moisture distribution directly after irrigation events are characterized throughout the lifecycle of a production crop. Reflection profiles produce high-resolution travel time data and summed results of CMP sounding data provide sampling depth estimates for the weak, but coherent reflections amid strong point scatterers. The high ratio of clay in the soil limits the resolution of downward propagation of infiltrating moisture after irrigation; synthetic data analysis compared against soil moisture lysimeter logs throughout the profile allow identification of the discrete soil moisture content variation in the measured GPR data. The nature of short duration irrigation events, evapotranspiration, and drainage behavior in relation to root depths observed in the GPR temporal data allow further examination and comparison with the variable saturation model HYDRUS-1D. After retrieving soil hydraulic properties derived from laboratory measured soil samples and simplified assumptions about boundary conditions, the project aims to achieve good agreement between simulated and measured soil moisture profiles without the need for excessive model calibration for GPR-derived soil moisture estimates in an agricultural setting.

Waveform Analysis of UWB GPR Antennas

Directory of Open Access Journals (Sweden)

Julia Armesto

2009-03-01

Full Text Available Ground Penetrating Radar (GPR systems fall into the category of ultra-wideband (UWB devices. Most GPR equipment covers a frequency range between an octave and a decade by using short-time pulses. Each signal recorded by a GPR gathers a temporal log of attenuated and distorted versions of these pulses (due to the effect of the propagation medium plus possible electromagnetic interferences and noise. In order to make a good interpretation of this data and extract the most possible information during processing, a deep knowledge of the wavelet emitted by the antennas is essential. Moreover, some advanced processing techniques require specific knowledge of this signal to obtain satisfactory results. In this work, we carried out a series of tests in order to determine the source wavelet emitted by a ground-coupled antenna with a 500 MHz central frequency.

Uso do radar penetrante no solo (GPR na investigação dos solos dos tabuleiros costeiros no litoral norte do estado da Bahia

Directory of Open Access Journals (Sweden)

J. M. Ucha

2002-06-01

Full Text Available Foram estudados nove perfis ao longo de uma toposseqüência sobre os sedimentos do Grupo Barreiras, na Fazenda Rio Negro, município de Entre Rios (BA, utilizando a prospecção eletromagnética por meio do Radar Penetrante no Solo - "Ground-penetrating radar - GPR", objetivando analisar a utilização dessa ferramenta na aquisição de informações sobre as feições que ocorrem no solo, mediante a comparação entre os radargramas obtidos e a descrição pedológica. O equipamento utilizado foi um Geophysical Survey System modelo GPR SR system-2, com antena de 80 MHz. A análise radargramétrica confirmou o aparecimento dos fragipãs e duripãs em profundidade, que ocorrem sempre acompanhados de um processo de transformação dos solos do tipo Latossolo Amarelo e Argissolo Amarelo em Espodossolo. Os padrões de reflexão mostram claramente os domínios dos solos argilosos e dos solos arenosos, com e sem a presença dos horizontes endurecidos.

Ground-Penetrating Radar Prospecting in the Peinan Archaeological Site, Taiwan

Directory of Open Access Journals (Sweden)

Lun-Tao Tong

2013-01-01

Full Text Available The Peinan archaeological site is the largest prehistoric village in Taiwan. Only small-scale pits are allowed for research purposes because the Peinan site is protected by the Cultural Heritage Preservation Act. Careful selection of the pit locations is crucial for future archaeological research at this site. In this study, a ground-penetrating radar (GPR survey was applied near the stone pillar to understand the GPR signatures of the subsurface remains. Seven GPR signatures were categorized based on the radar characters shown on the GPR image. A detailed GPR survey with dense parallel survey lines was subsequently conducted in the area of northern extent of the onsite exhibition to map the subsurface ancient buildings. The results were verified by two test pits, which indicate that the distribution of the subsurface building structures can be well recognized from GPR depth slices. It will be very helpful for setting proper pits priorities for future archaeological research, and for making proper design of the new onsite exhibition.

Design of a slimline directional borehole radar antenna using FDTD

CSIR Research Space (South Africa)

Vogt, D

2008-06-01

Full Text Available , dielectric. I. INTRODUCTION Borehole radar is the application of Ground Penetrating Radar (GPR) within a borehole [11]. GPR is a technique used to delineate structures and features of a subsurface. The borehole radar technique has been used successfully..., the direction of the incoming EM wave can be determined [6]. III. FILLER MATERIAL INSIDE ANTENNA ARRAY Ideally, there is no material between the antenna body and the rock surrounding it. In that case, the filler material would be matched to the dielectric...

Analysis of thin fractures with GPR: from theory to practice

Science.gov (United States)

Arosio, Diego; Zanzi, Luigi; Longoni, Laura; Papini, Monica

2017-04-01

Whenever we perform a GPR survey to investigate a rocky medium, being the ultimate purpose of the survey either to study the stability of a rock slope or to determine the soundness of a quarried rock block, we would like mainly to detect any fracture within the investigated medium and, possibly, to estimate the parameters of the fractures, namely thickness and filling material. In most of the practical cases, rock fracture thicknesses are very small when compared to the wavelength of the electromagnetic radiation generated by the GPR systems. In such cases, fractures are to be considered as thin beds, i.e. two interfaces whose distance is smaller than GPR resolving capability, and the reflected signal is the sum of the electromagnetic reverberation within the bed. According to this, fracture parameters are encoded in the thin bed complex response and in this work we propose a methodology based on deterministic deconvolution to process amplitude and phase information in the frequency domain to estimate fracture parameters. We first present some theoretical aspects related to thin bed response and a sensitivity analysis concerning fracture thickness and filling. Secondly, we deal with GPR datasets collected both during laboratory experiments and in the facilities of quarrying activities. In the lab tests fractures were simulated by placing materials with known electromagnetic parameters and controlled thickness in between two small marble blocks, whereas field GPR surveys were performed on bigger quarried ornamental stone blocks before they were submitted to the cutting process. We show that, with basic pre-processing and the choice of a proper deconvolving signal, results are encouraging although an ambiguity between thickness and filling estimates exists when no a-priori information is available. Results can be improved by performing CMP radar surveys that are able to provide additional information (i.e., variation of thin bed response versus offset) at the expense

Tree root mapping with ground penetrating radar

CSIR Research Space (South Africa)

Van Schoor, Abraham M

2009-09-01

Full Text Available In this paper, the application of ground penetrating radar (GPR) for the mapping of near surface tree roots is demonstrated. GPR enables tree roots to be mapped in a non-destructive and cost-effective manner and is therefore a useful prospecting...

An experiment on a sand-dune environment in Southern Venetian coast based on GPR, VES and documentary evidence

Directory of Open Access Journals (Sweden)

L. Tosi

2000-06-01

Full Text Available The internal structures of some surviving sand dunes and the ancient shore-lines along the coast south of Venice have been investigated integrating Ground Probing Radar (GPR profiles, Vertical Electrical Soundings (VES and water conductivity measurements in some boreholes. The GPR penetration depth has been limited (4-5 m,using a 400 MHz antenna by the high conductivity of salt water saturating pores of the shallow sediments. On the other hand, the excellent spatial resolution of the radar survey provided an estimate of internal dune bedding features, such as cross lamination and forwarding ancient covered coast-lines dated in the Thirties. The interpretation of the data, in particular along one line 360 m long intercepting a sizable sand-dune bank, seems to offer clues to the evolutional history of the coast line and the depth of transition from fresh-water to brackish-salt water. The water table was detected with electrical measurements and direct observations in boreholes, whereas the transition between fresh and salt water (brackish water was pointed out indirectly by the high energy absorption and total back-reflection of the EM waves, encountered at this boundary, and directly by the strong decrease in VES resistivity values.

The Application of GPR in Florida for Detecting Forensic Burials

Energy Technology Data Exchange (ETDEWEB)

S. K. Koppenjan; J. J. Schultz; S. Ono; H. Lee

2003-01-01

A study was performed at the University of Florida to measure ground penetrating radar(GPR) performance for detecting forensic burials. In controlled scenarios, 24 burials were constructed with pig cadavers. Two soils were utilized to represent two of the most common soil orders in Florida: an Entisol and an Ultisol. Graves were monitored on a monthly basis for time periods up to 21 months with grid data acquired with pulsed and swept-frequency GPR systems incorporating several different frequency antennas. A small subset of the graves was excavated to assess decomposition and relate to the GPR images during the test. The grave anomalies in the GPR depth profiles became less distinctive over time due to body decomposition and settling of the disturbed soil (backfill) as it compacted. Soil type was a major factor. Grave anomalies became more difficult to recognize over time for deep targets that were within clay. Forensic targets that were in sandy soil were recognized for the duration of this study. Time elapsed imagery will be presented to elucidate the changes, or lack thereof, of grave anomalies over the duration of this study. Further analysis was performed using Synthetic Aperture Radar (SAR) reconstruction of images in 2-D and 3-D.

Overview and comparative study of GPR international standards and guidelines - COST Action TU1208

Science.gov (United States)

Pajewski, Lara; Marciniak, Marian; Benedetto, Andrea; Tosti, Fabio

2016-04-01

Ground Penetrating Radar (GPR) can be effectively used for non-destructive testing of composite structures and diagnostics affecting the whole life-cycle of civil engineering works. Nevertheless, few recognised international standards exist in this field and inhomogeneous recommendations are present in different countries. Moreover, the levels of knowledge, awareness and experience regarding the use of GPR in civil engineering vary strongly across different European areas. The COST Action TU1208 is working hard on leveraging these differences, by sharing and disseminating knowledge and experience, as well as by developing guidelines and protocols for a safe and effective use of GPR in civil engineering. GPR users need to know which is the best way to conduct GPR measurements and what the quality level for the results should be. The TU1208 guidelines will ensure a higher efficiency and quality of GPR services and they will constitute a scientific basis for the introduction of European Standards on the application of GPR in civil engineering. The aim of this contribution is to present an in-depth overview and critical analysis of the existing GPR international and national standards and guidelines. The main documents considered in our work are listed and briefly described in the following. Three standards are provided by the American Society for Testing and Materials (ASTM), to guide the GPR use for subsurface investigation, evaluation of asphalt-covered concrete bridge decks, and determination of pavement-layer thickness: 1. ASTM D6432-11, Standard Guide for Using the Surface Ground Penetrating Radar Method for Subsurface Investigation, ASTM International, West Conshohocken, PA, 2011, www.astm.org, DOI: 10.1520/D6432-11. 2. ASTM D6087-08, Standard Test Method for Evaluating Asphalt-Covered Concrete Bridge Decks Using Ground Penetrating Radar, ASTM International, West Conshohocken, PA, 2008, www.astm.org, DOI: 10.1520/D6087-08. 3. ASTM D4748-10, Standard Test Method

GPR random noise reduction using BPD and EMD

Science.gov (United States)

Ostoori, Roya; Goudarzi, Alireza; Oskooi, Behrooz

2018-04-01

Ground-penetrating radar (GPR) exploration is a new high-frequency technology that explores near-surface objects and structures accurately. The high-frequency antenna of the GPR system makes it a high-resolution method compared to other geophysical methods. The frequency range of recorded GPR is so wide that random noise recording is inevitable due to acquisition. This kind of noise comes from unknown sources and its correlation to the adjacent traces is nearly zero. This characteristic of random noise along with the higher accuracy of GPR system makes denoising very important for interpretable results. The main objective of this paper is to reduce GPR random noise based on pursuing denoising using empirical mode decomposition. Our results showed that empirical mode decomposition in combination with basis pursuit denoising (BPD) provides satisfactory outputs due to the sifting process compared to the time-domain implementation of the BPD method on both synthetic and real examples. Our results demonstrate that because of the high computational costs, the BPD-empirical mode decomposition technique should only be used for heavily noisy signals.

PAVECHECK : integrating deflection and GPR for network condition surveys.

Science.gov (United States)

2009-01-01

The PAVECHECK data integration and analysis system was developed to merge Falling Weight : Deflectometer (FWD) and Ground Penetrating Radar (GPR) data together with digital video images of : surface conditions. In this study Global Positioning System...

Estimating porosity and solid dielectric permittivity in the Miami Limestone using high-frequency ground penetrating radar (GPR) measurements at the laboratory scale

Science.gov (United States)

Mount, Gregory J.; Comas, Xavier

2014-10-01

Subsurface water flow in South Florida is largely controlled by the heterogeneous nature of the karst limestone in the Biscayne aquifer and its upper formation, the Miami Limestone. These heterogeneities are amplified by dissolution structures that induce changes in the aquifer's material and physical properties (i.e., porosity and dielectric permittivity) and create preferential flow paths. Understanding such patterns are critical for the development of realistic groundwater flow models, particularly in the Everglades, where restoration of hydrological conditions is intended. In this work, we used noninvasive ground penetrating radar (GPR) to estimate the spatial variability in porosity and the dielectric permittivity of the solid phase of the limestone at centimeter-scale resolution to evaluate the potential for field-based GPR studies. A laboratory setup that included high-frequency GPR measurements under completely unsaturated and saturated conditions was used to estimate changes in electromagnetic wave velocity through Miami Limestone samples. The Complex Refractive Index Model was used to derive estimates of porosity and dielectric permittivity of the solid phase of the limestone. Porosity estimates of the samples ranged between 45.2 and 66.0% and showed good correspondence with estimates of porosity using analytical and digital image techniques. Solid dielectric permittivity values ranged between 7.0 and 13.0. This study shows the ability of GPR to image the spatial variability of porosity and dielectric permittivity in the Miami Limestone and shows potential for expanding these results to larger scales and other karst aquifers.

Tomographic site characterization using CPT, ERT, and GPR. Innovative Technology Summary Report

International Nuclear Information System (INIS)

None

2000-01-01

ARA developed a geophysical tomographic system that incorporates results from Electrical Resistivity Tomography (ERT) measurements and Ground Penetrating Radar (GPR) Tomography measurements. Both methods are useful for imaging subsurface structures and processes, however, GPR is more effective in sandy material and ERT is more effective in clayey material. CPT or drilling is used to deploy the electrodes in the subsurface

Ground Penetrating Radar (GPR) facies delineated shallow sedimentary records along a recently prograding coastal barrier adjoining the Bay of Bengal: Paradeep, Odisha, India

Science.gov (United States)

Layek, M. K.; Sengupta, P.; Mukherjee, A.

2017-12-01

Sea-level fluctuations, triggered by progradation of beach or marine regression, can be of various time-scales. The fluctuating history of a shoreline along a coastal barrier can be identified from the sedimentary features of accretion or erosion. The necessity of the understanding of the complex barrier dynamics and subsurface along the Paradeep coast (in the state of Odisha, India), adjacent to the Bay of Bengal, has been growing since the number of the harbor industrial projects and the inhabitants of this major port city of India increases. In this study area, high resolution ground penetrating radar (GPR) survey and its interpretation by GPR facies analysis, which considers the pattern/set of reflected electromagnetic signals, has proved to be a useful method for shallow-subsurface (up to 8 m) imaging. In order to perform this task, a GPR system with 200 MHZ antenna was employed to survey along (17 profiles) and across (21 profiles) the microtidal coastal barrier of Paradeep. The shapes and sizes of the accretional and erosional features like beach-ridge deposits, washover deposits, channel-and-fill, and scour-and-fill are delineated on the radargram after processing by Radan7® software. The internal geometry of the beach ridge is mapped accurately after the radar facies analysis which suggests the longshore drift of sediments from the nearby river mouths of Mahanadi, Devi and their tributaries. This GPR facies analysis revealed the existence of two types of palaeo-tidal channels of the study area - (a) larger channels which are perpendicular to the shoreline having channel width of about 400 m with maximum depth of 4.5 m from the surface and (b) smaller channels (width up to 60 m) which flow parallel to the shoreline. In case of Paradeep coastal barrier, seaward-dipping beach progradational facies is positioned within oblique erosional surfaces (13°-36°) below the horizontal erosional surface or facies boundary. This lead to delineate the cycles of erosion

Performance of ground-penetrating radar on granitic regoliths with different mineral composition

Science.gov (United States)

Breiner, J.M.; Doolittle, James A.; Horton, Radley M.; Graham, R.C.

2011-01-01

Although ground-penetrating radar (GPR) is extensively used to characterize the regolith, few studies have addressed the effects of chemical and mineralogical compositions of soils and bedrock on its performance. This investigation evaluated the performance of GPR on two different granitic regoliths of somewhat different mineralogical composition in the San Jacinto Mountains of southern California. Radar records collected at a site where soils are Alfisols were more depth restricted than the radar record obtained at a site where soils are Entisols. Although the Alfisols contain an argillic horizon, and the Entisols have no such horizon of clay accumulation, the main impact on GPR effectiveness is related to mineralogy. The bedrock at the Alfisol site, which contains more mafic minerals (5% hornblende and 20% biotite), is more attenuating to GPR than the bedrock at the Entisol site, where mafic mineral content is less (<1% hornblende and 10% biotite). Thus, a relatively minor variation in bedrock mineralogy, specifically the increased biotite content, severely restricts the performance of GPR. Copyright ?? 2011 by Lippincott Williams & Wilkins.

Quantification of Reflection Patterns in Ground-Penetrating Radar Data

Science.gov (United States)

Moysey, S.; Knight, R. J.; Jol, H. M.; Allen-King, R. M.; Gaylord, D. R.

2005-12-01

Radar facies analysis provides a way of interpreting the large-scale structure of the subsurface from ground-penetrating radar (GPR) data. Radar facies are often distinguished from each other by the presence of patterns, such as flat-lying, dipping, or chaotic reflections, in different regions of a radar image. When these patterns can be associated with radar facies in a repeated and predictable manner we refer to them as `radar textures'. While it is often possible to qualitatively differentiate between radar textures visually, pattern recognition tools, like neural networks, require a quantitative measure to discriminate between them. We investigate whether currently available tools, such as instantaneous attributes or metrics adapted from standard texture analysis techniques, can be used to improve the classification of radar facies. To this end, we use a neural network to perform cross-validation tests that assess the efficacy of different textural measures for classifying radar facies in GPR data collected from the William River delta, Saskatchewan, Canada. We found that the highest classification accuracies (>93%) were obtained for measures of texture that preserve information about the spatial arrangement of reflections in the radar image, e.g., spatial covariance. Lower accuracy (87%) was obtained for classifications based directly on windows of amplitude data extracted from the radar image. Measures that did not account for the spatial arrangement of reflections in the image, e.g., instantaneous attributes and amplitude variance, yielded classification accuracies of less than 65%. Optimal classifications were obtained for textural measures that extracted sufficient information from the radar data to discriminate between radar facies but were insensitive to other facies specific characteristics. For example, the rotationally invariant Fourier-Mellin transform delivered better classification results than the spatial covariance because dip angle of the

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....

On the feasibility of space-based radar ice sounding of the Antarctic ice sheet at P-band

DEFF Research Database (Denmark)

Dall, Jørgen; Kusk, Anders; Corr, Hugh

. In this study the feasibility of space-based radar ice sounding is assessed. A two-step approach is applied: (1) Key ice sheet parameters are estimated from the airborne POLARIS data acquired in Antarctica. (2) The performance of potential space-based ice sounding radars is simulated based on the estimated ice...... data analysis estimating the scattering patterns via the Doppler spectra of the POLARIS data. The scattering patterns of the ice surfaces are relevant because the geometry of a space-based radar increases the risk that off-nadir surface clutter masks the nadir depth-signal of interest. Currently...... the ice sheet model is being established and validated. At the symposium measured and simulated satellite waveforms will be compared, and the feasibility of space-based ice sounding will be addressed....

Temporal monitoring of the soil freeze-thaw cycles over snow-cover land by using off-ground GPR

KAUST Repository

Jadoon, Khan; Lambot, Sé bastien; Dimitrov, Marin; Weihermü ller, Lutz

2013-01-01

We performed off-ground ground-penetrating radar (GPR) measurements over a bare agricultural field to monitor the freeze-thaw cycles over snow-cover. The GPR system consisted of a vector network analyzer combined with an off-ground monostatic horn

INTERPRETATION OF COAL POTENTION USING GROUND PENETRATING RADAR (GPR METHOD

Directory of Open Access Journals (Sweden)

Rohmatul Wahidah

2018-01-01

Full Text Available Coal exposure founded at Klatak Kebo Ireng village in Besuki Tulungagung precisely in the vicinity of the river. Energy needs is increasing so the coal used for one of alternative energy source that can be used by society. This study was conducted to determine of the potential distribution coal modeling on geological structure. Identification of coal structure is using Ground Penetrating Radar (GPR 2005 it conducted because this method is more suitable for shallow of surveys. The location for taking data is around the river that showed to exposure. There are 5th lines of taken data with length about 50 until 100 meters. Data processing was done using of software Future series 2005. The data displayed with software in the color pattern to obtain based on the constant of dielectric and conductivity. The results of interpretation study are the data indicates that there is a coal on the overall trajectory. Only in 2nd track contain little of coal. The Coal layers are appear in processing the results of data is thickness about 6 at the top. In the area of study also found the cavity (cavity area which contained of several tracks. On the bottom of the track there is a pattern of coal reddish of yellow color which indicates that material contains of minerals.

Side-looking underground radar (SLUR): Physical modeling and case history

International Nuclear Information System (INIS)

Daniels, J.J.; Brower, J.

1998-01-01

A modification of conventional surface ground-penetrating radar (GPR) was conceived, tested, and successfully applied in the field at Brookhaven National Laboratory (BNL) to investigate waste pits. The modified GPR method consists of making measurements along a traverse line in a sloping trench with the radar's antenna oriented at an angle of up to 45 degree from the horizontal. The direction of propagation of the electromagnetic field for this configuration is not vertical, and the amount of energy scattered from objects that are oriented vertically relative to the energy scattered from horizontal layers is increased. This fundamental feature of side-looking underground radar (SLUR) measurements is illustrated by physical modeling. Measurements made along parallel trenches that are offset at different distances from a vertically oriented object provides GPR cross-sections with a primary plane of investigation that intersects the vertical feature at different depths. SLUR was used at BNL in conjunction with conventional surface GPR measurements (displayed as 3-D blocks and plan-view time slices) to enhance the vertical definition and improve the depth estimates of the waste pits

Civil Engineering Applications of Ground Penetrating Radar in Finland

Science.gov (United States)

Pellinen, Terhi; Huuskonen-Snicker, Eeva; Olkkonen, Martta-Kaisa; Eskelinen, Pekka

2014-05-01

Ground penetrating radar (GPR) has been used in Finland since 1980's for civil engineering applications. First applications in this field were road surveys and dam inspections. Common GPR applications in road surveys include the thickness evaluation of the pavement, subgrade soil evaluation and evaluation of the soil moisture and frost susceptibility. Since the 1990's, GPR has been used in combination with other non-destructive testing (NDT) methods in road surveys. Recently, more GPR applications have been adopted, such as evaluating bridges, tunnels, railways and concrete elements. Nowadays, compared with other countries GPR is relatively widely used in Finland for road surveys. Quite many companies, universities and research centers in Finland have their own GPR equipment and are involved in the teaching and research of the GPR method. However, further research and promotion of the GPR techniques are still needed since GPR could be used more routinely. GPR has been used to evaluate the air void content of asphalt pavements for years. Air void content is an important quality measure of pavement condition for both the new and old asphalt pavements. The first Finnish guideline was released in 1999 for the method. Air void content is obtained from the GPR data by measuring the dielectric value as continuous record. To obtain air void content data, few pavement cores must be taken for calibration. Accuracy of the method is however questioned because there are other factors that affect the dielectric value of the asphalt layer, in addition to the air void content. Therefore, a research project is currently carried out at Aalto University in Finland. The overall objective is to investigate if the existing GPR technique used in Finland is accurate enough to be used as QC/QA tool in assessing the compaction of asphalt pavements. The project is funded by the Finnish Transport Agency. Further research interests at Aalto University include developing new microwave asphalt

Forensic Application of FM-CW and Pulse Radar

Energy Technology Data Exchange (ETDEWEB)

S. K. Koppenjan; R. S. Freeland; M. L. Miller; R. E. Yoder

2003-01-01

Ground-penetrating radar (GPR) technology has supplied vital assistance in criminal investigations. However, law enforcement personnel desire further developments such that the technology is rapidly deployable, and that it provides both a simple user interface and sophisticated target identification. To assist in the development of target identification algorithms, our efforts involve gathering background GPR data for the various site conditions and circumstances that often typify clandestine burials. For this study, forensic anthropologists established shallow-grave plots at The University of Tennessee Anthropological Research Facility (ARF) that are specific to GPR research. These plots contain donated human cadavers lying in various configurations and depths, surrounded by assorted construction material and backfill debris. We scanned the plots using two GPR technologies: (1) a multi-frequency synthetic-aperture FM-CW radar (200-700 MHz) (GPR-X) developed by the U.S. Department of Energy's (DOE) Special Technologies Laboratory (STL), Bechtel Nevada (Koppenjan et al., 2000), and (2) a commercial pulse radar (SIR-20) manufactured by Geophysical Survey Systems, Inc. (400 and 900 MHz)(GSSI). The sweep-frequency data show the large biological mass decomposing within the torso as encircled ''hot spots.'' The 400-MHz pulse radar exhibit major horizontal reflectors above the body, with shadow reflectors (horizontal multiples) occurring beneath the body at 60 cm depth. The 400-MHz antenna was able to discern the grave walls and folded tarp covering the lower body. Under these moist, clay-rich conditions, the 900-MHz antenna was able to penetrate slightly beyond 30 cm beneath the concrete layer. However, neither system was able to penetrate beyond a one meter depth in the moist, clay-rich soil (fine, mixed, thermic Typic Paleudalf). Example scans from each system are provided, along with a discussion of the survey protocol and general performance.

GPR Image and Signal Processing for Pavement and Road Monitoring on Android Smartphones and Tablets

Science.gov (United States)

Benedetto, Francesco; Benedetto, Andrea; Tedeschi, Antonio

2014-05-01

Ground Penetrating Radar (GPR) is a geophysical method that uses radar pulses to image the subsurface. This non-destructive method uses electromagnetic radiation and detects the reflected signals from subsurface structures. It can detect objects, changes in material, and voids and cracks. GPR has many applications in a number of fields. In the field of civil engineering one of the most advanced technologies used for road pavement monitoring is based on the deployment of advanced GPR systems. One of the most relevant causes of road pavement damage is often referable to water intrusion in structural layers. In this context, GPR has been recently proposed as a method to estimate moisture content in a porous medium without preventive calibration. Hence, the development of methods to obtain an estimate of the moisture content is a crucial research field involving economic, social and strategic aspects in road safety for a great number of public and private Agencies. In particular, a recent new approach was proposed to estimate moisture content in a porous medium basing on the theory of Rayleigh scattering, showing a shift of the frequency peak of the GPR spectrum towards lower frequencies as the moisture content increases in the soil. Addressing some of these issues, this work proposes a mobile application, for smartphones and tablets, for GPR image and signal processing. Our application has been designed for the Android mobile operating system, since it is open source and android mobile platforms are selling the most smartphones in the world (2013). The GPR map can be displayed in black/white or color and the user can zoom and navigate into the image. The map can be loaded in two different ways: from the local memory of the portable device or from a remote server. This latter possibility can be very useful for real-time and mobile monitoring of road and pavement inspection. In addition, the application allows analyzing the GPR data also in the frequency domain. It is

GPR Diagnostics of columns in archaeological contexts

Science.gov (United States)

Soldovieri, Francesco; Masini, Nicola; Persico, Raffaele; Catapano, Ilaria

2017-04-01

In the last decade the use of Ground Penetrating radar (GPR) applied to cultural heritage has been strongly increasing thanks to both technological development of sensors and softwares for data processing and cultural reasons such as the increasing awareness of conservators and archaeologist of the benefits of this method in terms of reduction of costs and time and risk associated with restoration works. This made GPR a mature technique for investigating different types of works of art and building elements of historical interest, including masonry structures, frescoes, mosaics [1-3], in the context of scientific projects, decision support activities aimed at the diagnosis of decay pathologies, and educational activities. One of the most complex building elements to be investigated by GPR are the columns both for the geometry of the object and for the several expected features to be detected including fractures, dishomogeneities and metallic connection elements. The work deals with the Ground Penetrating Radar diagnostic surveys at the prestigious archaeological site of Pompei. In particular, GPR surveys were carried out in two different areas, Palestra Grande and Tempio di Giove. The first campaign was carried out also as educational activity of the "International School "GEOPHYSICS AND REMOTE SENSING FOR ARCHAEOLOGY". The School aimed at giving the opportunity to scholars, PhD students, researchers and specialists in Geophysics, Remote Sensing and Archaeology to deepen their knowledge and expertise with geophysical and remote sensing techniques for archaeology and cultural heritage documentation and management. This survey was carried on two kinds of columns, with circular and rectangular section in order to detect possible hidden defects affecting their integrity. The second survey was carried out at Tempio di Giove, on request of the Soprintendenza Pompei, in order to gain information about the presence of reinforcement structures, which may be put inside the

Study of a rehabilitated road using GPR and FWD

Science.gov (United States)

Marecos, Vania; Fontul, Simona; de Lurdes Antunes, Maria; Solla, Mercedes; Pajewski, Lara

2017-04-01

This work focus on the structural evaluation of a rehabilitated road after the conclusion of the first phase of the improvement works. The activities developed in the study comprised the characterization of the pavement layers condition (before the application of the asphalt surface layer) and the prediction of the pavement bearing capacity (taking into account the contribution of the wearing course, to be placed in accordance with the project specifications). For this study two non-destructive tests (NDT) were combined: Falling Weight Deflectometer (FWD) and Ground Penetrating Radar (GPR). The original pavement was essentially composed by a granular layer treated with a bituminous emulsion. The main objectives of the rehabilitation works were the enlargement of the road platform in selected locations, with the construction of a new pavement, and also the reinforcement of the existing pavement to increase its bearing capacity. The FWD tests were performed to assess the bearing capacity of the pavement and were conducted along the outer wheel path, in both directions. The spacing between measurement points was 75 m and the applied impulse load was 50 kN. The results showed a great variability of the deflections measured along the section under study. A preliminary zonation of the pavement was carried out, and was latter adjusted based on the results of the GPR. To determine the thickness of the pavement layers a GPR survey was carried out using a 1.8 GHz antenna and a radar control unit SIR-20, both from GSSI. The GPR tests were performed continuously along the same line as the FWD tests. The GPR tests allowed for the identification of the different structures of the pavement, corresponding to the zones with the new pavement and the existing pavement with reinforcement. Some cores were extracted to calibrate the thickness of the GPR bituminous layers, to verify the conditions of adhesion between layers and also to perform laboratory tests to characterize the

Pemfokusan Citra Radar untuk Hasil Pemodelan Radar Penembus Permukaan menggunakan Algoritma Migrasi Jarak

Directory of Open Access Journals (Sweden)

AZIZAH AZIZAH

2016-02-01

Full Text Available ABSTRAK Citra Radar Penembus Permukaan (GPR memberikan gambaran tentang objek dalam bentuk kurva hiperbola. Kurva hiperbola ini memiliki resolusi yang rendah sehingga sulit untuk menganalisis lokasi objek yang sebenarnya. Oleh karena itu diperlukan proses untuk membuat citra menjadi lebih fokus. Proses ini disebut transformasi atau migrasi. Salah satu algoritma migrasi adalah algoritma migrasi jarak. Terdapat beberapa langkah yang dilakukan dalam penelitian ini. Pertama, pemodelan GPR dilakukan menggunakan perangkat lunak. Kemudian, algoritma migrasi jarak diimplementasikan untuk data hasil pemodelan. Terakhir, dilakukan analisis hasil yang didapat. Informasi jumlah dan lokasi objek didapatkan dari citra hasil migrasi ini dengan persentase kesalahan untuk pada sumbu x sebesar 4 % untuk 1 objek, 17 % untuk 2 objek, dan 4 % untuk 3 objek. Sedangkan persentase kesalahan pada sumbu y sebesar 2% untuk 1 objek, 3% untuk 2 objek, dan 8% untuk 3 objek. Kata kunci: GPR, migrasi, algoritma, migrasi jarak, fokus, ABSTRACT Ground Penetrating Radar (GPR image give description about object in hyperbolic curve. This hyperbolic curve has low resolution so it is too difficult to analysis the actual object position. Therefore, we need a process can make the image more focus. This process usually called transformation or migration. One of them is range migration algorithm. There are several steps in this reseacrh. First, GPR modelling done using software. Next, range migration algorithm is implemented for the data result from simulation. Last, the result are analyzed. The information about the number and object position is obtained from the image in this migration process with margin error in x-axis are 4% for 1 object, 17% for 2 object, and 4% for 3 object. On the other side, margin error in y-axis are 2% for 1 object, 4% for 2 object, and 8% for 3 object. Keywords: GPR, migration, algorithm, range migration, focus

GPR measurements of attenuation in concrete

Science.gov (United States)

Eisenmann, David; Margetan, Frank J.; Pavel, Brittney

2015-03-01

Ground-penetrating radar (GPR) signals from concrete structures are affected by several phenomenon, including: (1) transmission and reflection coefficients at interfaces; (2) the radiation patterns of the antenna(s) being used; and (3) the material properties of concrete and any embedded objects. In this paper we investigate different schemes for determining the electromagnetic (EM) attenuation of concrete from measured signals obtained using commercially-available GPR equipment. We adapt procedures commonly used in ultrasonic inspections where one compares the relative strengths of two or more signals having different travel paths through the material of interest. After correcting for beam spread (i.e., diffraction), interface phenomena, and equipment amplification settings, any remaining signal differences are assumed to be due to attenuation thus allowing the attenuation coefficient (say, in dB of loss per inch of travel) to be estimated. We begin with a brief overview of our approach, and then discuss how diffraction corrections were determined for our two 1.6 GHz GPR antennas. We then present results of attenuation measurements for two types of concrete using both pulse/echo and pitch/catch measurement setups.

GPR measurements of attenuation in concrete

International Nuclear Information System (INIS)

Eisenmann, David; Margetan, Frank J.; Pavel, Brittney

2015-01-01

Ground-penetrating radar (GPR) signals from concrete structures are affected by several phenomenon, including: (1) transmission and reflection coefficients at interfaces; (2) the radiation patterns of the antenna(s) being used; and (3) the material properties of concrete and any embedded objects. In this paper we investigate different schemes for determining the electromagnetic (EM) attenuation of concrete from measured signals obtained using commercially-available GPR equipment. We adapt procedures commonly used in ultrasonic inspections where one compares the relative strengths of two or more signals having different travel paths through the material of interest. After correcting for beam spread (i.e., diffraction), interface phenomena, and equipment amplification settings, any remaining signal differences are assumed to be due to attenuation thus allowing the attenuation coefficient (say, in dB of loss per inch of travel) to be estimated. We begin with a brief overview of our approach, and then discuss how diffraction corrections were determined for our two 1.6 GHz GPR antennas. We then present results of attenuation measurements for two types of concrete using both pulse/echo and pitch/catch measurement setups

GPR measurements of attenuation in concrete

Energy Technology Data Exchange (ETDEWEB)

Eisenmann, David, E-mail: djeisen@cnde.iastate.edu; Margetan, Frank J., E-mail: djeisen@cnde.iastate.edu; Pavel, Brittney, E-mail: djeisen@cnde.iastate.edu [Center for Nondestructive Evaluation, Iowa State University, 1915 Scholl Road, Ames, IA 50011-3042 (United States)

2015-03-31

Ground-penetrating radar (GPR) signals from concrete structures are affected by several phenomenon, including: (1) transmission and reflection coefficients at interfaces; (2) the radiation patterns of the antenna(s) being used; and (3) the material properties of concrete and any embedded objects. In this paper we investigate different schemes for determining the electromagnetic (EM) attenuation of concrete from measured signals obtained using commercially-available GPR equipment. We adapt procedures commonly used in ultrasonic inspections where one compares the relative strengths of two or more signals having different travel paths through the material of interest. After correcting for beam spread (i.e., diffraction), interface phenomena, and equipment amplification settings, any remaining signal differences are assumed to be due to attenuation thus allowing the attenuation coefficient (say, in dB of loss per inch of travel) to be estimated. We begin with a brief overview of our approach, and then discuss how diffraction corrections were determined for our two 1.6 GHz GPR antennas. We then present results of attenuation measurements for two types of concrete using both pulse/echo and pitch/catch measurement setups.

Neural network based inspection of voids and karst conduits in hydro-electric power station tunnels using GPR

Science.gov (United States)

Kilic, Gokhan; Eren, Levent

2018-04-01

This paper reports on the fundamental role played by Ground Penetrating Radar (GPR), alongside advanced processing and presentation methods, during the tunnel boring project at a Dam and Hydro-Electric Power Station. It identifies from collected GPR data such issues as incomplete grouting and the presence of karst conduits and voids and provides full details of the procedures adopted. In particular, the application of collected GPR data to the Neural Network (NN) method is discussed.

Some examples of GPR prospecting for monitoring of the monumental heritage

International Nuclear Information System (INIS)

Masini, Nicola; Persico, Raffaele; Rizzo, Enzo

2010-01-01

In this paper three case histories of ground penetrating radar (GPR) for the monitoring of historical buildings are presented. They aim to present the specific valence of the GPR in the field of the diagnostic of historical buildings, which is a promising field of research, due to the increasing awareness of the relevance (even economic) of the cultural heritage. The presented GPR prospecting cases have been performed on three different constructive elements typical of historical buildings (a wall, a masonry pillar and a marble column) in order to be the answer to different problems such as the characterization of the masonry, the detection of cracks and the imaging of metallic reinforcement bars

Potential of Probing the Lunar Regolith using Rover-Mounted Ground Penetrating Radar: Moses Lake Dune Field Analog Study

Science.gov (United States)

Horz, F.; Heggy, E.; Fong, T.; Kring, D.; Deans, M.; Anglade, A.; Mahiouz, K.; Bualat, M.; Lee, P.; Bluethmann, W.

2009-01-01

Probing radars have been widely recognized by the science community to be an efficient tool to explore lunar subsurface providing a unique capability to address several scientific and operational issues. A wideband (200 to 1200 MHz) Ground Penetrating Radar (GPR) mounted on a surface rover can provide high vertical resolution and probing depth from few tens of centimeters to few tens of meters depending on the sounding frequency and the ground conductivity. This in term can provide a better understand regolith thickness, elemental iron concentration (including ilmenite), volatile presence, structural anomalies and fracturing. All those objectives are of important significance for understanding the local geology and potential sustainable resources for future landing sites in particular exploring the thickness, structural heterogeneity and potential volatiles presence in the lunar regolith. While the operation and data collection of GPR is a straightforward case for most terrestrial surveys, it is a challenging task for remote planetary study especially on robotic platforms due to the complexity of remote operation in rough terrains and the data collection constrains imposed by the mechanical motion of the rover and limitation in data transfer. Nevertheless, Rover mounted GPR can be of great support to perform systematic subsurface surveys for a given landing site as it can provide scientific and operational support in exploring subsurface resources and sample collections which can increase the efficiency of the EVA activities for potential human crews as part of the NASA Constellation Program. In this study we attempt to explore the operational challenges and their impact on the EVA scientific return for operating a rover mounted GPR in support of potential human activity on the moon. In this first field study, we mainly focused on the ability of GPR to support subsurface sample collection and explore shallow subsurface volatiles.

Radar-eddy current GPR

OpenAIRE

A. O. Abramovych

2014-01-01

Introduction. At present there are many electrical schematic metal detectors (the most common kind of ground penetrating radar), which are differ in purpose. Each scheme has its own advantages and disadvantages compared to other schemes. Designing metal detector problem of optimal selection of functional units most schemes can only work with a narrow range of special purpose units. Functional units used in circuits can be replaced by better ones, but specialization schemes do not provide such...

A Ground Penetrating Radar (GPR) Survey of KIilbourne Hole, Southern New Mexico: Implication for Paleohydrology and Near Surface Geophysical Exploration of Mars and the Moon

Science.gov (United States)

Rhodes, N.; Hurtado, J. M.

2013-05-01

Features such as the Home Plate plateau on Mars, a suspected remnant of a phreatomagmatic eruption, can reveal important information about paleohydrologic conditions. The types and sizes of pyroclastic rocks produced by a phreatomagmatic eruption are indicative of the behavior of the explosion and the characteristics of the groundwater reservoir. Analysis of the pyroclast size distribution can be used to determine magma volatile content. We conduct an analysis of pyroclast size distribution using Ground Penetrating Radar (GPR) to make a quantitative estimate of the presence of past groundwater at Kilbourne Hole, a well-known phreatomagmatic crater located in southern Dona Ana County, New Mexico. As basaltic magma intruded the groundwater reservoir in the mid-Pleistocene, the water vaporized and caused a phreatomagmatic explosion that excavated the 2-km wide and 200-m deep depression. The pyroclastic units produced during a phreatomagmatic explosion are proportional to the size and the duration of the explosion and the size of the groundwater reservoir such that the wetter the eruption, the stronger the explosion. In a violent volcanic eruption, magma changes from a liquid into solid fragments and the explosion releases kinetic energy (Ek) by ejecting liquid water, vapor water (with mass Mw) and solid fragments (with mass Mf) at an ejection velocity (Ve). In order to determine Mw, we must know Ve. The relationship between Ve and the distance from center of the eruption (R) is such that Ve exponentially decreases with time (t) and R. A numerical model relating pyroclast size and Ve for material ejected in Hawaiian and Plinian eruptions shows that clast size also exponentially decreases with decreasing Ve. Based on these relationships, we use GPR to map the ejected clast size distribution as a function of distance from the edge of Kilbourne Hole in an effort to determine Ve and Mw. GPR surveys were performed in January 2012 and January 2013 using a Noggins 250 MHz

GPR Imaging of Clastic Dikes at the Hanford Site, Hanford, Washington

International Nuclear Information System (INIS)

Clement, William P.; Murray, Christopher J.

2007-01-01

We use ground penetrating radar (GPR) data to help determine the spatial distribution and the subsurface geometry of clastic injection dikes at the Hanford site. This information will help to improve the understanding of the hydrological role of these ubiquitous clastic dikes at the Hanford Site. We collected 100 MHz ground penetrating radar (GPR) 3D surface reflection data at two sites, the S-16 Pond and the Army Loop Road sites, and 2D reflection data along a 6.9 km linear transect near the Army Loop Road site. The dikes are distinguished in the GPR data by a strongly attenuated zone, disruptions in the continuity of reflections, and diffractions where reflections are disrupted. In general, the data quality is better at the Army Loop Road and Traverse sites than at the S-16 Pond site, probably due to the presence of cobbles at the S-16 Pond site. A high-moisture, fine-grained unit probably causes the strong reflections at the Army Loop Road site and the Traverse survey site. The signal penetration varies between 5 to 12 m below the land surface

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...

Temporal monitoring of the soil freeze-thaw cycles over snow-cover land by using off-ground GPR

KAUST Repository

Jadoon, Khan

2013-07-01

We performed off-ground ground-penetrating radar (GPR) measurements over a bare agricultural field to monitor the freeze-thaw cycles over snow-cover. The GPR system consisted of a vector network analyzer combined with an off-ground monostatic horn antenna, thereby setting up an ultra-wideband stepped-frequency continuous-wave radar. Measurements were performed during nine days and the surface of the bare soil was exposed to snow fall, evaporation and precipitation as the GPR antenna was mounted 110 cm above the ground. Soil surface dielectric permittivity was retrieved using an inversion of time-domain GPR data focused on the surface reflection. The GPR forward model used combines a full-waveform solution of Maxwell\\'s equations for three-dimensional wave propagation in planar layered media together with global reflection and transmission functions to account for the antenna and its interactions with the medium. Temperature and permittivity sensors were installed at six depths to monitor the soil dynamics in the top 8 cm depth. Significant effects of soil dynamics were observed in the time-lapse GPR, temperature and permittivity data and in particular freeze and thaw events were clearly visible. A good agreement of the trend was observed between the temperature, permittivity and GPR time-lapse data with respect to five freeze-thaw cycles. The GPR-derived permittivity was in good agreement with sensor observations. The proposed method appears to be promising for the real-time mapping and monitoring of the frozen layer at the field scale. © 2013 IEEE.

GPR use and activities in the Czech Republic

Science.gov (United States)

Stryk, Josef; Matula, Radek

2014-05-01

In the field of civil engineering applications in the Czech Republic, Ground Penetrating Radar (GPR) is used particularly for the diagnostics of roads and bridges. There is no producer of GPR in the Czech Republic, sets of different producers are used, particularly Geophysical Survey Systems, Inc. (USA) and MALÅ GeoScience (Sweden). The measurement results are mostly processed by software Radan, Road Doctor Pro, ReflexW and RadEx. The only technical specification in the Czech Republic is TP 233 issued by the Ministry of Transport, which describes the diagnostics of roads by GPR. Apart from a basic description of the method and a measurement system, it mentions possible applications. The only application where accuracy is mentioned is the locating of dowels and tie bars in concrete road pavements, which states that if calibration is performed, the expected depth accuracy is up to 1.0 cm. The following R&D project is currently in progress: New diagnostics methods as a supporting decision tool for maintenance and repair of road pavements - their contribution and ways of their usage (2012-2014) The project aims to test possible non-destructive methods (particularly GPR and laser scanning), make recommendations when and how to use specific methods for individual applications and for changes in technical specifications. The following R&D projects have been recently completed: Position of dowels and tie bars in rigid pavements and importance of their correct placement to pavement performance and service life (2012-2013) The project included an analysis of individual NDT methods used for the location of dowels and tie bars and for testing of their accuracy - GPR, MIT-scan and GPR in combination with a metal detector. Multichannel ground penetrating radar as a tool for monitoring of road and bridge structures (2009-2011) The project included detection of hollow spaces under non-reinforced concrete pavements, detection of excessive amount of water in road construction

Waveform analysis of crosshole GPR data collected in heterogeneous chalk deposits

DEFF Research Database (Denmark)

Keskinen, Johanna; Nielsen, Lars; Zibar, Majken Caroline Looms

2014-01-01

Chalks are important reservoirs for groundwater production onshore Denmark and for hydrocarbons in the North Sea Basin. Therefore this rock type is studied extensively with geological and geophysical methods. Ground-penetrating radar (GPR) tomography is used to characterize fine-scale reservoir...

Assessment of waterfront location in hardened concrete by GPR within COST Action TU1208

Science.gov (United States)

Rodríguez-Abad, Isabel; Klysz, Gilles; Balayssac, Jean Paul; Pajewski, Lara

2016-04-01

This work focuses on the analysis of the capability of Ground-Penetrating radar (GPR) technique for evaluating how the water penetrates into concrete samples by means of the assessment of the waterfront advance. Research activities have been carried out during a Short-Term Scientific Missions (STSMs) funded by the COST (European Cooperation in Science and Technology) Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar" in November 2015. The evaluation of water penetrability is crucial in most building materials, such us concrete, since, water and aggressive chemical agents dissolved therein contribute to the deterioration of the material. A number of techniques have been developed to measure their advance in concrete. Although the most common method for measuring water content is the gravimetric method by observing the change in mass, this method has a large number of disadvantages. In this context, non-destructive techniques as GPR play an interesting role. In particular, the application of GPR in the building materials area is providing very promising and interesting results regarding the building materials characterization and especially concrete deterioration evaluation [1-3]. In addition, recent experimental studies highlight the strong relation between wave propagation parameters (velocity and energy level) and water content advance [4-5]. Water content has a decisive influence on dielectric properties and those might be assessed by the study of the wave properties that are derived by using GPR. Therefore, the waterfront advance will result in a change on wave parameters. In line with this, this research is focused on the development of specific processing algorithms necessary to understand how the water penetrates and how the wave parameters will be affected regarding the location of the antenna in reference to the water absorption direction. For this purpose, concrete samples were manufactured, which after curing (90 days) and oven

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

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...

Design and performance Assessment of an Airborne Ice Sounding Radar Front-End

DEFF Research Database (Denmark)

Hernández, Carlos Cilla; Krozer, Viktor; Vidkjær, Jens

2008-01-01

The paper describes the design and experimental performance assessment of the RF front-end of an airborne P-band ice sounding radar. The ice sounder design features newly developed components at a centre frequency of 435 MHz, such as, antenna 20% bandwidth at RL ≪ 13 dB, compact high power in...

Use of Ground Penetrating Radar for Locating Contraband Aboard Ocean Going Vessels: Feasibility Study

National Research Council Canada - National Science Library

Llopis, Jose

2001-01-01

Ground Penetrating Radar (GPR) surveys were conducted over various stockpiled materials at the Alabama state Docks located in Mobile, AL, to determine whether GPR is a viable method for rapidly detecting contraband materials...

Mapping soil water content on golf course greens with GPR

Science.gov (United States)

Ground-penetrating radar (GPR) can be an effective and efficient method for high-resolution mapping of volumetric water content in the sand layer directly beneath the ground surface at a golf course green. This information could potentially be very useful to golf course superintendents for determi...

Estimating belowground carbon stocks in isolated wetlands of the Northern Everglades Watershed, central Florida, using ground penetrating radar (GPR) and aerial imagery

Science.gov (United States)

McClellan, Matthew; Comas, Xavier; Hinkle, Ross; Sumner, David M.

2017-01-01

Peat soils store a large fraction of the global soil carbon (C) pool and comprise 95% of wetland C stocks. While isolated freshwater wetlands in temperate and tropical biomes account for more than 20% of the global peatland C stock, most studies of wetland soil C have occurred in expansive peatlands in northern boreal and subarctic biomes. Furthermore, the contribution of small depressional wetlands in comparison to larger wetland systems in these environments is very uncertain. Given the fact that these wetlands are numerous and variable in terms of their internal geometry, innovative methods are needed for properly estimating belowground C stocks and their overall C contribution to the landscape. In this study, we use a combination of ground penetrating radar (GPR), aerial imagery, and direct measurements (coring) in conjunction with C core analysis to develop a relation between C stock and surface area, and estimate the contribution of subtropical depressional wetlands to the total C stock of pine flatwoods at the Disney Wilderness Preserve (DWP), Florida. Additionally, GPR surveys were able to image collapse structures underneath the peat basin of depressional wetlands, depicting lithological controls on the formation of depressional wetlands at the DWP. Results indicate the importance of depressional wetlands as critical contributors to the landscape C budget at the DWP and the potential of GPR-based approaches for (1) rapidly and noninvasively estimating the contribution of depressional wetlands to regional C stocks and (2) evaluating the formational processes of depressional wetlands.

GPR and GPS data integration: examples of application in Antarctica

Directory of Open Access Journals (Sweden)

S. Gandolfi

2001-06-01

Full Text Available Ground Penetrating Radar (GPR and Global Positioning System (GPS techniques were employed in snow accumulation studies during the Italian leg of the International Trans-Antarctic Scientific Expedition (ITASE. The acquired data were useful both for glaciological and climatological studies. This paper presents some results obtained by GPR and GPS data integration employed to determine accumulation/ablation processes along the profile of the traverse that show how the snow-sublayer thickness can vary quickly in just a few kilometres. Some examples of data integration employed in detection and characterisation of buried crevasses are also presented.

Microwave tomography for an effective imaging in GPR on UAV/airborne observational platforms

Science.gov (United States)

Soldovieri, Francesco; Catapano, Ilaria; Ludeno, Giovanni

2017-04-01

GPR was originally thought as a non-invasive diagnostics technique working in contact with the underground or structure to be investigated. On the other hand, in the recent years several challenging necessities and opportunities entail the necessity to work with antenna not in contact with the structure to be investigated. This necessity arises for example in the case of landmine detection but also for cultural heritage diagnostics. Other field of application regards the forward-looking GPR aiming at shallower hidden targets forward the platfrom (vehicle) carrying the GPR [1]. Finally, a recent application is concerned with the deployment of airborne/UAV GPR, able to ensure several advantages in terms of large scale surveys and "freedom" of logistics constraint [2]. For all the above mentioned cases, the interest is towards the development of effective data processing able to make imaging task in real time. The presentation will show different data processing strategies, based on microwave tomography [1,2], for a reliable and real time imaging in the case of GPR platforms far from the interface of the structure/underground to be investigated. [1] I. Catapano, A. Affinito, A. Del Moro,.G. Alli, and F. Soldovieri, "Forward-Looking Ground-Penetrating Radar via a Linear Inverse Scattering Approach," IEEE Transactions on Geoscience and Remote Sensing, vol. 53, pp. 5624 - 5633, Oct. 2015. [2] I. Catapano, L. Crocco, Y. Krellmann, G. Triltzsch, and F. Soldovieri, "A tomographic approach for helicopter-borne ground penetrating radar imaging," IEEE Geosci. Remote Sens. Lett., vol. 9, no. 3, pp. 378-382, May 2012.

Onboard Data Processors for Planetary Ice-Penetrating Sounding Radars

Science.gov (United States)

Tan, I. L.; Friesenhahn, R.; Gim, Y.; Wu, X.; Jordan, R.; Wang, C.; Clark, D.; Le, M.; Hand, K. P.; Plaut, J. J.

2011-12-01

Among the many concerns faced by outer planetary missions, science data storage and transmission hold special significance. Such missions must contend with limited onboard storage, brief data downlink windows, and low downlink bandwidths. A potential solution to these issues lies in employing onboard data processors (OBPs) to convert raw data into products that are smaller and closely capture relevant scientific phenomena. In this paper, we present the implementation of two OBP architectures for ice-penetrating sounding radars tasked with exploring Europa and Ganymede. Our first architecture utilizes an unfocused processing algorithm extended from the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS, Jordan et. al. 2009). Compared to downlinking raw data, we are able to reduce data volume by approximately 100 times through OBP usage. To ensure the viability of our approach, we have implemented, simulated, and synthesized this architecture using both VHDL and Matlab models (with fixed-point and floating-point arithmetic) in conjunction with Modelsim. Creation of a VHDL model of our processor is the principle step in transitioning to actual digital hardware, whether in a FPGA (field-programmable gate array) or an ASIC (application-specific integrated circuit), and successful simulation and synthesis strongly indicate feasibility. In addition, we examined the tradeoffs faced in the OBP between fixed-point accuracy, resource consumption, and data product fidelity. Our second architecture is based upon a focused fast back projection (FBP) algorithm that requires a modest amount of computing power and on-board memory while yielding high along-track resolution and improved slope detection capability. We present an overview of the algorithm and details of our implementation, also in VHDL. With the appropriate tradeoffs, the use of OBPs can significantly reduce data downlink requirements without sacrificing data product fidelity. Through the development

GPR para a verificação do nível d'água subterrânea em transição floresta amazônica e cerrado Ground Penetratin Radar (GPR water level monitoring study of a mature transitional tropical forest

Directory of Open Access Journals (Sweden)

Tânia Helena Marcelino

2005-09-01

Full Text Available Um estudo do monitoramento do nível de água foi realizado com medidas diretas e com Radar de Penetração no Solo (GPR em uma floresta tropical de transição para o cerrado. Três poços de monitoramento do nível de água foram instalados durante 2001/2002 em três locais diferentes: o primeiro em uma área de floresta permanente, outro em área de floresta manejada e outra em uma área de pasto. Os perfis de GPR mostram que o nível do topo do lençol freático aparece como um refletor horizontal forte em março e em agosto de 2002, e como um refletor fraco durante medidas em maio e outubro de 2001 com descontinuidades devido a diversas lentes de solo laterítico no solo. O topo do lençol de água é facilmente confundido com a presença de tais lentes. A umidade do solo teve uma influência nestes sinais da reflexão, mudando a constante dielétrica do solo. A profundidade do topo do lençol da água variou 1,8 m sob a floresta permanente, 0,9 m sob a floresta manejada e 3,7 m sob o pasto.A Ground Penetratin Radar (GPR water level monitoring study of a mature transitional tropical forest is presented. Three water tables monitoring wells were installed during 2001/2002 at three different sites: under permanent forest, under managed forest and pasture. The GPR profiles show that the water table appears as a strong horizontal reflector in March and August, 2002,and as a weak, discontinuous reflector during measurements in May and October 2001. Due to several laterite lenses in the soil, the water table can easily be mistaken in place of such lenses. Soil moisture had an influence on these reflection signals, changing the dielectric constant of soil. The depth of the water table varied 1.8 m under permanent forest, 0.9 m under management forest and 3.7 m under pasture.

The Use of Ground Penetrating Radar to Exploring Sedimentary Ore In North-Central Saudi Arabia

Science.gov (United States)

Almutairi, Yasir; Almutair, Muteb

2015-04-01

Ground Penetrating Radar (GPR) is a non-destructive geophysical method that provides a continuous subsurface profile, without drilling. This geophysical technique has great potential in delineating the extension of bauxites ore in north-central Saudi Arabia. Bauxite is from types sedimentary ores. This study aim to evaluate the effectiveness of Ground Penetrating Radar (GPR) to illustrate the subsurface feature of the Bauxite deposits at some selected mining areas north-central Saudi Arabia. Bauxite is a heterogeneous material that consists of complex metals such as alumina and aluminum. An efficient and cost-effect exploration method for bauxite mine in Saudi Arabia is required. Ground penetrating radar (GPR) measurements have been carrying out along outcrop in order to assess the potential of GPR data for imaging and characterising different lithological facies. To do so, we have tested different antenna frequencies to acquire the electromagnetic signals along a 90 m profile using the IDS system. This system equipped with a 25 MHz antenna that allows investigating the Bauxite layer at shallow depths where the clay layers may existed. Therefore, the 25 MHz frequency antenna has been used in this study insure better resolution of the subsurface and to get more penetration to image the Bauxite layer. After the GPR data acquisition, this data must be processed in order to be more easily visualized and interpreted. Data processing was done using Reflex 6.0 software. A series of tests were carried out in frequency filtering on a sample of radar sections, which was considered to better represent the entire set of data. Our results indicated that the GPR profiling has a very good agreement for mapping the bauxite layer depth at range of 7 m to 11 m. This study has emphasized that the high-resolution GPR method is the robust and cost-effect technique to map the Bauxite layer. The exploration of Bauxite resource using the GPR technique could reduce the number of holes to

Advies voor de toepassing van ground-penetrating radar bij de inventarisatie van de grondwaterdynamiek

NARCIS (Netherlands)

Knotters, M.

2001-01-01

Ground-penetrating radar (GPR) biedt mogelijk een nauwkeurig alternatief voor arbeidsintensieve metingen van de grondwaterstand in boorgaten. De GPR-metingen kunnen als hulpinformatie dienen bij geostatistische interpolatie van grondwaterstanden. Op basis van literatuurstudie en verkenning van het

A systematic method for characterizing the time-range performance of ground penetrating radar

International Nuclear Information System (INIS)

Strange, A D

2013-01-01

The fundamental performance of ground penetrating radar (GPR) is linked to the ability to measure the signal time-of-flight in order to provide an accurate radar-to-target range estimate. Having knowledge of the actual time range and timing nonlinearities of a trace is therefore important when seeking to make quantitative range estimates. However, very few practical methods have been formally reported in the literature to characterize GPR time-range performance. This paper describes a method to accurately measure the true time range of a GPR to provide a quantitative assessment of the timing system performance and detect and quantify the effects of timing nonlinearity due to timing jitter. The effect of varying the number of samples per trace on the true time range has also been investigated and recommendations on how to minimize the effects of timing errors are described. The approach has been practically applied to characterize the timing performance of two commercial GPR systems. The importance of the method is that it provides the GPR community with a practical method to readily characterize the underlying accuracy of GPR systems. This in turn leads to enhanced target depth estimation as well as facilitating the accuracy of more sophisticated GPR signal processing methods. (paper)

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.

GPR Signal Denoising and Target Extraction With the CEEMD Method

KAUST Repository

Li, Jing

2015-04-17

In this letter, we apply a time and frequency analysis method based on the complete ensemble empirical mode decomposition (CEEMD) method in ground-penetrating radar (GPR) signal processing. It decomposes the GPR signal into a sum of oscillatory components, with guaranteed positive and smoothly varying instantaneous frequencies. The key idea of this method relies on averaging the modes obtained by empirical mode decomposition (EMD) applied to several realizations of Gaussian white noise added to the original signal. It can solve the mode-mixing problem in the EMD method and improve the resolution of ensemble EMD (EEMD) when the signal has a low signal-to-noise ratio. First, we analyze the difference between the basic theory of EMD, EEMD, and CEEMD. Then, we compare the time and frequency analysis with Hilbert-Huang transform to test the results of different methods. The synthetic and real GPR data demonstrate that CEEMD promises higher spectral-spatial resolution than the other two EMD methods in GPR signal denoising and target extraction. Its decomposition is complete, with a numerically negligible error.

GPR Technologies and Methodologies in Italy: A Review

Science.gov (United States)

Benedetto, Andrea; Frezza, Fabrizio; Manacorda, Guido; Massa, Andrea; Pajewski, Lara

2014-05-01

GPR techniques and technologies have been subject of intense research activities at the Italian level in the last 15 years because of their potential applications specifically to civil engineering. More in detail, several innovative approaches and models have been developed to inspect road pavements to measure the thickness of their layers as well as to diagnose or prevent damage. Moreover, new frontiers in bridge inspection as well as in geotechnical applications such as slides and flows have been investigated using GPR. From the methodological viewpoint, innovative techniques have been developed to solve GPR forward-scattering problems, as well to locate and classify subsurface targets in real-time and to retrieve their properties through multi-resolution strategies, and linear and non-linear methodologies. Furthermore, the application of GPR and other non-destructive testing methods in archaeological prospecting, cultural heritage diagnostics, and in the localization and detection of vital signs of trapped people has been widely investigated. More recently, new theoretical and empirical paradigms regarding water moisture evaluation in various porous media and soil characterization have been published as the results of long terms research activities. Pioneer studies are also currently under development with the scope to correlate GPR measurement with mechanical characteristics of bound and unbound construction materials. In such a framework, this abstract will be aimed at reviewing some of the most recent advances of GPR techniques and technologies within the Italian industrial and academic communities [also including their application within international projects such as FP7 ISTIMES (http://www.istimes.eu)], and at envisaging some of the most promising research trends currently under development. Acknowledgment - This work was supported by COST Action TU1208 'Civil Engineering Applications of Ground Penetrating Radar' References [1] M. Balsi, S. Esposito, F

GPR Laboratory Tests For Railways Materials Dielectric Properties Assessment

Directory of Open Access Journals (Sweden)

Francesca De Chiara

2014-10-01

Full Text Available In railways Ground Penetrating Radar (GPR studies, the evaluation of materials dielectric properties is critical as they are sensitive to water content, to petrographic type of aggregates and to fouling condition of the ballast. Under the load traffic, maintenance actions and climatic effects, ballast condition change due to aggregate breakdown and to subgrade soils pumping, mainly on existing lines with no sub ballast layer. The main purpose of this study was to validate, under controlled conditions, the dielectric values of materials used in Portuguese railways, in order to improve the GPR interpretation using commercial software and consequently the management maintenance planning. Different materials were tested and a broad range of in situ conditions were simulated in laboratory, in physical models. GPR tests were performed with five antennas with frequencies between 400 and 1800 MHz. The variation of the dielectric properties was measured, and the range of values that can be obtained for different material condition was defined. Additionally, in situ GPR measurements and test pits were performed for validation of the dielectric constant of clean ballast. The results obtained are analyzed and the main conclusions are presented herein.

A guidelines handbook for GPR surveys in tunnels: a COST Action TU1208 contribution

Science.gov (United States)

Bianchini Ciampoli, Luca; Alani, Amir M.; Pajewski, Lara; Benedetto, Andrea; Loizos, Andreas; Tosti, Fabio

2016-04-01

A significant open issue concerning the reliability of geophysical methods and in particular of ground penetrating radar (GPR), both in research and professional context, is a general lack of international standards. This is a major problem to be faced, in order to gain scientific strictness for the GPR practices, and to easily extend to the international community the results achieved within the area of single virtuous countries. Producing international guidelines can represent an important step forward, in this sense. In the memorandum of understanding of the COST Action TU1208 is clearly stated that one of the main purposes of the Action is the "development of innovative protocols and guidelines which will be published in a handbook and constitute a basis for European Standards, for an effective GPR application in CE tasks; safety, economic and financial criteria will be integrated within the protocols". Of course this is not a simple task to be accomplished. Firstly, survey procedures are highly dependent on the objective of the survey itself. On the basis of the objective of each geophysical test, the GPR system, the antenna configuration, and even the processing procedures may change. Besides, these procedures are also influenced by the environmental conditions in which the tests are performed. This affects several aspects spanning from hardware to software, but including, for instance, also safety issues. Due to these reasons, one of the main goal of the COST Action TU1208 is the development of several guidelines related to the main applications of GPR in the field of civil engineering. In this work, the structure of a guidelines handbook for GPR activities in tunnels is outlined. In the first sections, the principal references in the field are provided, and the most common GPR equipment and complementary technologies are described. Subsequently, the survey methodologies are explained. Particular attention is paid to the preliminary activities to be carried

Radar facies of unconsolidated sediments in The Netherlands : A radar stratigraphy interpretation method for hydrogeology

NARCIS (Netherlands)

Overmeeren, R.A. van

1998-01-01

Since 1990, The Netherlands Institute of Applied Geoscience TNO has been carrying out ground penetrating radar (GPR) measurements to assess the potential for imaging and characterising different hydrogeological targets in more than 30 pilot areas in The Netherlands. The experience gained by

GPR capabilities for ice thickness sampling of low salinity ice and for detecting oil in ice

Energy Technology Data Exchange (ETDEWEB)

Lalumiere, Louis [Sensors by Design Ltd. (Canada)

2011-07-01

This report discusses the performance and capabilities test of two airborne ground-penetrating radar (GPR) systems of the Bedford Institute of Oceanography (BIO), Noggin 1000 and Noggin 500, for monitoring low salinity snow and ice properties which was used to measure the thickness of brackish ice on Lake Melville in Labrador and on a tidal river in Prince Edward Island. The work of other researchers is documented and the measurement techniques proposed are compared to the actual GPR approach. Different plots of GPR data taken over snow and freshwater ice and over ice with changing salinity are discussed. An interpretation of brackish ice GPR plots done by the Noggin 1000 and Noggin 500 systems is given based on resolution criterion. Additionally, the capability of the BIO helicopter-borne GPR to detect oil-in-ice has been also investigated, and an opinion on the likelihood of the success of GPR as an oil-in-ice detector is given.

Design of a low cost miniaturized SFCW GPR with initial results

Science.gov (United States)

Duggal, Swati; Sinha, Piyush; Gupta, Manish; Patel, Anand; Vedam, V. V.; Mevada, Pratik; Chavda, Rajesh; Shah, Amita; Putrevu, Deepak

2016-05-01

This paper discusses about the design &developmental of Ground Penetrating Radar (GPR), various scientific and commercial applications of GPR along with the testing and results of GPR at Antarctica for Ice thickness measurement. GPR instruments are categorised as per their frequency of operation, which is inversely proportional to the depth of penetration. GPRs are also categorized as per method of operation which is time-domain or frequency-domain. Indian market is presently procuring GPRs from only foreign suppliers. Space Applications Centre (SAC) had taken up GPR as R&D Technological development with a view to benchmark the technology which may be transferred to local industry for mass production of instrument at a relatively cheaper cost (~20 times cheaper). Hence, this instrument presents a viable indigenous alternative. Also, the design and configuration was targeted for terrestrial as well as future interplanetary (Lander/Rover) missions of ISRO to map subsurface features. The developed GPR has a very large bandwidth (100%, i.e. bandwidth of 500MHz with centre-frequency of 500MHz) and high dynamic range along with the advantage of being highly portable (<10kg). The system was configured as a Stepped-Frequency-Continuous-Wave (SFCW) GPR which is a frequency domain GPR with the aim to increase the detection capabilities with respect to current systems. In order to achieve this goal, innovative electronic equipment have been designed and developed. Three prototypes were developed and two of them have been delivered for Indian Scientific Expedition to Antarctica (ISEA) in 2013 and 2014-15, respectively and promising results have been obtained. The results from the same closely compare with that from commercial GPR too.

High resolution aquifer characterization using crosshole GPR full-waveform tomography

Science.gov (United States)

Gueting, N.; Vienken, T.; Klotzsche, A.; Van Der Kruk, J.; Vanderborght, J.; Caers, J.; Vereecken, H.; Englert, A.

2016-12-01

Limited knowledge about the spatial distribution of aquifer properties typically constrains our ability to predict subsurface flow and transport. Here, we investigate the value of using high resolution full-waveform inversion of cross-borehole ground penetrating radar (GPR) data for aquifer characterization. By stitching together GPR tomograms from multiple adjacent crosshole planes, we are able to image, with a decimeter scale resolution, the dielectric permittivity and electrical conductivity of an alluvial aquifer along cross-sections of 50 m length and 10 m depth. A logistic regression model is employed to predict the spatial distribution of lithological facies on the basis of the GPR results. Vertical profiles of porosity and hydraulic conductivity from direct-push, flowmeter and grain size data suggest that the GPR predicted facies classification is meaningful with regard to porosity and hydraulic conductivity, even though the distributions of individual facies show some overlap and the absolute hydraulic conductivities from the different methods (direct-push, flowmeter, grain size) differ up to approximately one order of magnitude. Comparison of the GPR predicted facies architecture with tracer test data suggests that the plume splitting observed in a tracer experiment was caused by a hydraulically low-conductive sand layer with a thickness of only a few decimeters. Because this sand layer is identified by GPR full-waveform inversion but not by conventional GPR ray-based inversion we conclude that the improvement in spatial resolution due to full-waveform inversion is crucial to detect small-scale aquifer structures that are highly relevant for solute transport.

Advanced GPR imaging of sedimentary features: integrated attribute analysis applied to sand dunes

Science.gov (United States)

Zhao, Wenke; Forte, Emanuele; Fontolan, Giorgio; Pipan, Michele

2018-04-01

We evaluate the applicability and the effectiveness of integrated GPR attribute analysis to image the internal sedimentary features of the Piscinas Dunes, SW Sardinia, Italy. The main objective is to explore the limits of GPR techniques to study sediment-bodies geometry and to provide a non-invasive high-resolution characterization of the different subsurface domains of dune architecture. On such purpose, we exploit the high-quality Piscinas data-set to extract and test different attributes of the GPR trace. Composite displays of multi-attributes related to amplitude, frequency, similarity and textural features are displayed with overlays and RGB mixed models. A multi-attribute comparative analysis is used to characterize different radar facies to better understand the characteristics of internal reflection patterns. The results demonstrate that the proposed integrated GPR attribute analysis can provide enhanced information about the spatial distribution of sediment bodies, allowing an enhanced and more constrained data interpretation.

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...

GPR Raw-Data Order Statistic Filtering and Split-Spectrum Processing to Detect Moisture

Directory of Open Access Journals (Sweden)

Gokhan Kilic

2014-05-01

Full Text Available Considerable research into the area of bridge health monitoring has been undertaken; however, information is still lacking on the effects of certain defects, such as moisture ingress, on the results of ground penetrating radar (GPR surveying. In this paper, this issue will be addressed by examining the results of a GPR bridge survey, specifically the effect of moisture in the predicted position of the rebars. It was found that moisture ingress alters the radargram to indicate distortion or skewing of the steel reinforcements, when in fact destructive testing was able to confirm that no such distortion or skewing had occurred. Additionally, split-spectrum processing with order statistic filters was utilized to detect moisture ingress from the GPR raw data.

Beach-ridge architecture constrained by beach topography and Ground-Penetrating Radar, Itilleq (Lakse Bugt), Disko, Greenland – Implications for sea-level reconstructions

DEFF Research Database (Denmark)

Emerich Souza, Priscila; Kroon, Aart; Nielsen, Lars

2018-01-01

Detailed topographical data and high-resolution ground-penetrating radar (GPR) reflection data are presented from the present-day beach and across successive raised beach-ridges at Itilleq (Disko, West Greenland). In the western part of our study area, the present low-tide level is well-marked by......Detailed topographical data and high-resolution ground-penetrating radar (GPR) reflection data are presented from the present-day beach and across successive raised beach-ridges at Itilleq (Disko, West Greenland). In the western part of our study area, the present low-tide level is well...... beach-ridge GPR profiles. Most of them are located at the boundary between a unit with reflection characteristics representing palaeo foreshore deposits, and a deeper and more complex radar unit characterized by diffractions, which, however, is not penetrated to large depths by the GPR signals. Based...

A Novel Probability Model for Suppressing Multipath Ghosts in GPR and TWI Imaging: A Numerical Study

Directory of Open Access Journals (Sweden)

Tan Yun-hua

2015-10-01

Full Text Available A novel concept for suppressing the problem of multipath ghosts in Ground Penetrating Radar (GPR and Through-Wall Imaging (TWI is presented. Ghosts (i.e., false targets mainly arise from the use of the Born or single-scattering approximations that lead to linearized imaging algorithms; however, these approximations neglect the effect of multiple scattering (or multipath between the electromagnetic wavefield and the object under investigation. In contrast to existing methods of suppressing multipath ghosts, the proposed method models for the first time the reflectivity of the probed objects as a probability function up to a normalized factor and introduces the concept of random subaperture by randomly picking up measurement locations from the entire aperture. Thus, the final radar image is a joint probability distribution that corresponds to radar images derived from multiple random subapertures. Finally, numerical experiments are used to demonstrate the performance of the proposed methodology in GPR and TWI imaging.

Imaging the Antarctic Ice Sheet Subsurface with the HF GPR TAPIR

Science.gov (United States)

Le Gall, A.; Ciarletti, V.; Berthelier, J.; Reineix, A.; Ney, R.; Bonaimé, S.; Corbel, C.

2006-12-01

An HF impulse polarimetric Ground Penetrating Radar (GPR) operating at very low frequencies (ranging from ~2 to 8MHz) has been developed in the frame of the NetLander mission. This instrument, named TAPIR (Terrestrial And Planetary Investigation by Radar), was designed to probe the Martian subsurface down to kilometric depth and search for potential water reservoirs. Although the NetLander mission was cancelled in 2003, the interest on the exploration of Martian subsurface was recently enhanced by the promising observations of the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) on board of the ESA Mars Express orbiter. In particular, MARSIS detected the base of the North Polar Layered Deposits, penetrating up to ~1.8km the ice-rich upper layer of the underground. Such results suggest that TAPIR, which operates in the same frequency range as MARSIS and can performed a higher number of coherent integrations, is able to reach deeper structures. Yet, in contrast with classical GPRs, TAPIR can not move onto the surface and thus won't provide 2D or 3D scan of the subsurface. To retrieve, in spite of this NetLander restraint, the 3D distribution of the reflecting facets of the underground, the instrument was equipped with two electrical dipoles and a rotating magnetic sensor. These antennas allow to derive, from the measured values of 5 components of the wave field, the direction of arrival of the reflected waves hence the inclination of the buried reflectors. The first validation of this innovative concept was carried out during the RANETA (RAdar of NEtlander in Terre Adélie) campaign organized by the Institute Paul-Emile Victor in January-February 2004. This campaign took place on the Antarctic ice sheet close to the French-Italian Cap Prudhomme station. 8 soundings of the ice shelf were performed on various sites corresponding to different altitudes above the sea level (ranging from ~285m to ~1100m). We shall provide a detailed description of the

Pipe Penetrating Radar: a New Tool for the Assessment of Critical Infrastructure

Science.gov (United States)

Ekes, C.; Neducz, B.

2012-04-01

This paper describes the development of Pipe Penetrating Radar (PPR), the underground in-pipe application of GPR, a non-destructive testing method that can detect defects and cavities within and outside mainline diameter (>18 in / 450mm) non-metallic (concrete, PVC, HDPE, etc.) underground pipes. The method uses two or more high frequency GPR antennae carried by a robot into underground pipes. The radar data is transmitted to the surface via fibre optic cable and is recorded together with the output from CCTV (and optionally sonar and laser). Proprietary software analyzes the data and pinpoints defects or cavities within and outside the pipe. Thus the testing can identify existing pipe and pipe bedding symptoms that can be addressed to prevent catastrophic failure due to sinkhole development and can provide useful information about the remaining service life of the pipe. The key innovative aspect is the unique ability to map pipe wall thickness and deterioration including cracks and voids outside the pipe, enabling accurate predictability of needed intervention or the timing of replacement. This reliable non-destructive testing method significantly impacts subsurface infrastructure condition based asset management by supplying previously unattainable measurable conditions. Keywords: pipe penetrating radar (PPR), ground penetrating radar (GPR), pipe inspection, concrete deterioration, municipal engineering

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...

GPR Use and Activities in Denmark

Science.gov (United States)

Ringgaard, Jørgen; Wisén, Roger

2014-05-01

Academic work on GPR in Denmark is performed both by the Technical University of Denmark (DTU) and the University of Copenhagen (KU). The work at DTU includes development of antennas and systems, e.g. an airborne ice-sounder GPR system (POLARIS) that today is in frequent use for monitoring of ice thickness in Greenland. DTU often collaborates with ESA (European Space Agency) regarding electromagnetic development projects. At KU there is an ongoing work with GPR applied to water resources. The main objective is to study flux of water and matter across different hydrological domains. There are several recent publications from KU describing research for data analysis and modelling as well as hydro geophysical applications. Also the Geological Survey of Denmark and Greenland (GEUS) performs frequent geological mapping with GPR. There have been mainly two actors on the Danish commercial market for several years: FalkGeo and Ramboll. Falkgeo has been active for many years acquiring data for several different applications such as archeology, utilities and roads. Their equipment pool comprises both a multichannel Terravision system form GSSI and a 2D system from Mala Geoscience with a comprehensive range of antennas. Ramboll has performed GPR surveys for two decades mainly with 2D systems from GSSI. In recent years Ramboll has also obtained a system with RTA antennas from Mala Geoscience and a multichannel system from 3D-Radar. These systems have opened markets both for deeper geological mapping and for shallow mapping. The geological mapping with the Mala system has often been combined with resistivity imaging (CVES) and refraction seismic. The 3D system has been applied in airports and on road for mapping of layer thicknesses, delamination and for control of asphalt works. Other areas comprise bridge deck evaluation and utility mapping. Ramboll also acts as client advisor for BaneDanmark, a state owned company who operates and develops the Danish state railway network

Accurate Antenna Models in Ground Penetrating Radar Diffraction Tomography

DEFF Research Database (Denmark)

Meincke, Peter; Kim, Oleksiy S.

2002-01-01

are modeled by their plane-wave receiving and transmitting spectra. We find these spectra numerically for a resistively loaded dipole using the method of moments. Also, we illustrate, through a numerical example, the importance of taking into account the correct antenna pattern in GPR diffraction tomography.......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...

Internal structure of a barrier beach as revealed by ground penetrating radar (GPR): Chesil beach, UK

Science.gov (United States)

Bennett, Matthew R.; Cassidy, Nigel J.; Pile, Jeremy

2009-03-01

Chesil Beach (Dorset) is one of the most famous coastal landforms on the British coast. The gravel beach is over 18 km long and is separated for much of its length from land by a tidal lagoon known as The Fleet. The beach links the Isle of Portland in the east to the mainland in the west. Despite its iconic status there is little available information on its internal geometry and evolutionary history. Here we present a three-fold model for the evolution of Chesil Beach based on a series of nine ground penetrating radar (GPR) traverses located at three sites along its length at Abbotsbury, Langton Herring and at Ferry Bridge. The GPR traverses reveal a remarkably consistent picture of the internal structure of this barrier beach. The first phase of evolution involves the landward transgression of a small sand and gravel beach which closed upon the coast leading to deposition of freshwater peat between 5 and 7 k yr BP. The second evolutionary phase involves the 'bulking-out' of the beach during continued sea level rise, but in the presence of abundant gravel supplied by down-drift erosion of periglacial slope deposits. This episode of growth was associated with a series of washover fans which accumulated on the landward flank of the barrier increasing its breadth and height but without significant landward transgression of the barrier as a whole. The final phase in the evolution of Chesil Beach involves the seaward progradation of the beach crest and upper beach face associated with continued sediment abundance, but during a still-stand or slight fall in relative sea level. This phase may provide further evidence of a slight fall in relative sea level noted elsewhere along the South Coast of Britain and dated to between 1.2 and 2.4 k yr BP. Subsequently the barrier appears to have become largely inactive, except for the reworking of sediment on the beach face during storm events. The case study not only refines the evolutionary picture of Chesil Beach, but

Application of ground penetrating radar in placer mineral exploration for mapping subsurface sand layers: A case study

Digital Repository Service at National Institute of Oceanography (India)

Loveson, V.J.; Barnwal, R.P.; Singh, V.K.; Gujar, A.R.; Rajamanickam, G.V.

radar reflections using time-domain reflectometry and sedimentological analyses, Sedimentology, v. 47, p. 435-449. Jol, H.M. & Bristow, C.S., 2003. GPR in sediments: advice on data collection, basic processing and interpretation, a good practice... guide, In: Bristow, C.S. and Jol, H.M. (Eds.), GPR in sediments, Geological Society of London, Special Publication, 211. Neal, A., 2004. Ground Penetrating Radar and its use in sedimentology: Principles, Problems and Progress. Earth-Science Reviews...

TOMOGRAPHIC SITE CHARACTERIZATION USING CPT, ERT, AND GPR

Energy Technology Data Exchange (ETDEWEB)

Rexford M. Morey; Susanne M. Conklin; Stephen P. Farrington, P.E.; James D. Shinn II, P.E.

1999-07-01

The US Department of Energy (DOE) is responsible for the cleanup of inactive DOE sites and for bringing DOE sites and facilities into compliance with federal, state, and local laws and regulations. The DOE's Office of Environmental Management (EM) needs advanced technologies that can make environmental restoration and waste management operations more efficient and less costly. These techniques are required to better characterize the physical, hydrogeological, and chemical properties of the subsurface while minimizing and optimizing the use of boreholes and monitoring wells. Today the cone penetrometer technique (CPT) is demonstrating the value of a minimally invasive deployment system for site characterization. Applied Research Associates, Inc. is developing two new sensor packages for site characterization and monitoring. The two new methods are: (1) Electrical Resistivity Tomography (ERT); and (2) Ground Penetrating Radar (GPR) Tomography. These sensor systems are now integrated with the CPT. The results of this program now make it possible to install ERT and GPR units by CPT methods and thereby reduce installation costs and total costs for ERT and GPR surveys. These two techniques can complement each other in regions of low resistivity where ERT is more effective and regions of high resistivity where GPR is more effective. The results show that CPT-installed GeoWells can be used for both ERT and GPR borehole tomographic subsurface imaging. These two imaging techniques can be used for environmental site characterization and monitoring have numerous and diverse applications within site cleanup and waste management operations.

Improving mine recognition through processing and Dempster-Shafer fusion of ground-penetrating radar data

NARCIS (Netherlands)

Milisavljević, N.; Bloch, I.; Broek, S.P. van den; Acheroy, M.

2003-01-01

A methodfor modeling andcombination of measures extractedfrom a ground-penetrating radar (GPR) in terms of belief functions within the Dempster-Shafer framework is presentedandillustratedon a real GPR data set. A starting point in the analysis is a preprocessed C-scan of a sand-lane containing some

Linear GPR inversion for lossy soil and a planar air-soil interface

DEFF Research Database (Denmark)

Meincke, Peter

2001-01-01

A three-dimensional inversion scheme for fixed-offset ground penetrating radar (GPR) is derived that takes into account the loss in the soil and the planar air-soil interface. The forward model of this inversion scheme is based upon the first Born approximation and the dyadic Green function...

Analyses of GPR signals for characterization of ground conditions in urban areas

Science.gov (United States)

Hong, Won-Taek; Kang, Seonghun; Lee, Sung Jin; Lee, Jong-Sub

2018-05-01

Ground penetrating radar (GPR) is applied for the characterization of the ground conditions in urban areas. In addition, time domain reflectometry (TDR) and dynamic cone penetrometer (DCP) tests are conducted for the accurate analyses of the GPR images. The GPR images are acquired near a ground excavation site, where a ground subsidence occurred and was repaired. Moreover, the relative permittivity and dynamic cone penetration index (DCPI) are profiled through the TDR and DCP tests, respectively. As the ground in the urban area is kept under a low-moisture condition, the relative permittivity, which is inversely related to the electromagnetic impedance, is mainly affected by the dry density and is inversely proportional to the DCPI value. Because the first strong signal in the GPR image is shifted 180° from the emitted signal, the polarity of the electromagnetic wave reflected at the dense layer, where the reflection coefficient is negative, is identical to that of the first strong signal. The temporal-scaled GPR images can be accurately converted into the spatial-scaled GPR images using the relative permittivity determined by the TDR test. The distribution of the loose layer can be accurately estimated by using the spatial-scaled GPR images and reflection characteristics of the electromagnetic wave. Note that the loose layer distribution estimated in this study matches well with the DCPI profile and is visually verified from the endoscopic images. This study demonstrates that the GPR survey complemented by the TDR and DCP tests, may be an effective method for the characterization of ground conditions in an urban area.

Antenna characteristics and air-ground interface deembedding methods for stepped-frequency ground-penetrating radar measurements

DEFF Research Database (Denmark)

Karlsen, Brian; Larsen, Jan; Jakobsen, Kaj Bjarne

2000-01-01

The result from field-tests using a Stepped-Frequency Ground Penetrating Radar (SF-GPR) and promising antenna and air-ground deembedding methods for a SF-GPR is presented. A monostatic S-band rectangular waveguide antenna was used in the field-tests. The advantages of the SF-GPR, e.g., amplitude...... and phase information in the SF-GPR signal, is used to deembed the characteristics of the antenna. We propose a new air-to-ground interface deembedding technique based on Principal Component Analysis which enables enhancement of the SF-GPR signal from buried objects, e.g., anti-personal landmines...

Analysis of the Emitted Wavelet of High-Resolution Bowtie GPR Antennas

Directory of Open Access Journals (Sweden)

Manuel Pereira

2009-06-01

Full Text Available Most Ground Penetrating Radars (GPR cover a wide frequency range by emitting very short time wavelets. In this work, we study in detail the wavelet emitted by two bowtie GPR antennas with nominal frequencies of 800 MHz and 1 GHz. Knowledge of this emitted wavelet allows us to extract as much information as possible from recorded signals, using advanced processing techniques and computer simulations. Following previously published methodology used by Rial et al. [1], which ensures system stability and reliability in data acquisition, a thorough analysis of the wavelet in both time and frequency domain is performed. Most of tests were carried out with air as propagation medium, allowing a proper analysis of the geometrical attenuation factor. Furthermore, we attempt to determine, for each antenna, a time zero in the records to allow us to correctly assign a position to the reflectors detected by the radar. Obtained results indicate that the time zero is not a constant value for the evaluated antennas, but instead depends on the characteristics of the material in contact with the antenna.

Observing of tree trunks and other cylindrical objects using GPR

Science.gov (United States)

Jezova, Jana; Lambot, Sebastien

2016-04-01

Trees are a part of our everyday life, hence it is important to prevent their collapse to protect people and urban infrastructures. It is also important to characterize tree wood properties for usages in construction. In order to investigate internal parts of tree trunks non-invasively, ground-penetrating radar (GPR), or in this case, ultra-wideband microwave radar as a general tool, appears to be a very promising technology. Nevertheless, tree trunk tomography using microwave radar is a complicated task due to the circular shape of the trunk and the very complex (heterogeneous and anisotropic) internal structures of the trunk. Microwave sensing of tree trunks is also complicated due to the electromagnetic properties of living wood, which strongly depend on water content, density and temperature of wood. The objective of this study is to describe tree trunk radar cross sections including specific features originating from the particular circumferential data acquisition geometry. In that respect, three experiments were performed: (1) numerical simulations using a finite-difference time-domain software, namely, gprMax 2D, (2) measurements on a simplified laboratory trunk model including plastic and cardboard pipes, sand and air, and (3) measurements over a real tree trunk. The analysis was further deepened by considering: (1) common zero-offset reflection imaging, (2) imaging with a planar perfect electrical conductor (PEC) at the opposite side of the trunk, and (3) imaging with a PEC arc at the opposite side of the trunk. Furthermore, the shape of the reflection curve of a cylindrical target was analytically derived based on the straight-ray propagation approximation. Subsequently, the total internal reflection (TIR) phenomenon occurring in cylindrical objects was observed and analytically described. Both the straight-ray reflection curve and TIR were well observed on the simulated and laboratory radar data. A comparison between all experiments and radar

Electromagnetic signal penetration in a planetary soil simulant: Estimated attenuation rates using GPR and TDR in volcanic deposits on Mount Etna

Science.gov (United States)

Lauro, S. E.; Mattei, E.; Cosciotti, B.; Di Paolo, F.; Arcone, S. A.; Viccaro, M.; Pettinelli, E.

2017-07-01

Ground-penetrating radar (GPR) is a well-established geophysical terrestrial exploration method and has recently become one of the most promising for planetary subsurface exploration. Several future landing vehicles like EXOMARS, 2020 NASA ROVER, and Chang'e-4, to mention a few, will host GPR. A GPR survey has been conducted on volcanic deposits on Mount Etna (Italy), considered a good analogue for Martian and Lunar volcanic terrains, to test a novel methodology for subsoil dielectric properties estimation. The stratigraphy of the volcanic deposits was investigated using 500 MHz and 1 GHz antennas in two different configurations: transverse electric and transverse magnetic. Sloping discontinuities have been used to estimate the loss tangents of the upper layer of such deposits by applying the amplitude-decay and frequency shift methods and approximating the GPR transmitted signal by Gaussian and Ricker wavelets. The loss tangent values, estimated using these two methodologies, were compared and validated with those retrieved from time domain reflectometry measurements acquired along the radar profiles. The results show that the proposed analysis, together with typical GPR methods for the estimation of the real part of permittivity, can be successfully used to characterize the electrical properties of planetary subsurface and to define some constraints on its lithology of the subsurface.

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...

IMF-Slices for GPR Data Processing Using Variational Mode Decomposition Method

Directory of Open Access Journals (Sweden)

Xuebing Zhang

2018-03-01

Full Text Available Using traditional time-frequency analysis methods, it is possible to delineate the time-frequency structures of ground-penetrating radar (GPR data. A series of applications based on time-frequency analysis were proposed for the GPR data processing and imaging. With respect to signal processing, GPR data are typically non-stationary, which limits the applications of these methods moving forward. Empirical mode decomposition (EMD provides alternative solutions with a fresh perspective. With EMD, GPR data are decomposed into a set of sub-components, i.e., the intrinsic mode functions (IMFs. However, the mode-mixing effect may also bring some negatives. To utilize the IMFs’ benefits, and avoid the negatives of the EMD, we introduce a new decomposition scheme termed variational mode decomposition (VMD for GPR data processing for imaging. Based on the decomposition results of the VMD, we propose a new method which we refer as “the IMF-slice”. In the proposed method, the IMFs are generated by the VMD trace by trace, and then each IMF is sorted and recorded into different profiles (i.e., the IMF-slices according to its center frequency. Using IMF-slices, the GPR data can be divided into several IMF-slices, each of which delineates a main vibration mode, and some subsurface layers and geophysical events can be identified more clearly. The effectiveness of the proposed method is tested using synthetic benchmark signals, laboratory data and the field dataset.

Ducted electromagnetic waves in the Martian ionosphere detected by the Mars Advanced Radar for Subsurface and Ionosphere Sounding radar

Science.gov (United States)

Zhang, Zhenfei; Orosei, Roberto; Huang, Qian; Zhang, Jie

2016-07-01

In the data of the Mars Advanced Radar for Subsurface and Ionosphere Sounding on board the European Space Agency (ESA) mission Mars Express (MEX), a distinctive type of signals (called the "epsilon signature"), which is similar to that previously detected during radio sounding of the terrestrial F region ionosphere, is found. The signature is interpreted to originate from multiple reflections of electromagnetic waves propagating along sounder pulse-created, crustal magnetic field-aligned plasma bubbles (waveguides). The signatures have a low (below 0.5%) occurrence rate and apparent cutoff frequencies 3-5 times higher than the theoretical one for an ordinary mode wave. These properties are explained by the influence of the perpendicular ionospheric plasma density gradient and the sounder pulse frequency on the formation of waveguides.

Results from Field Testing the RIMFAX GPR on Svalbard.

Science.gov (United States)

Hamran, S. E.; Amundsen, H. E. F.; Berger, T.; Carter, L. M.; Dypvik, H.; Ghent, R. R.; Kohler, J.; Mellon, M. T.; Nunes, D. C.; Paige, D. A.; Plettemeier, D.; Russell, P.

2017-12-01

The Radar Imager for Mars' Subsurface Experiment - RIMFAX is a Ground Penetrating Radar being developed for NASÁs MARS 2020 rover mission. The principal goals of the RIMFAX investigation are to image subsurface structures, provide context for sample sites, derive information regarding subsurface composition, and search for ice or brines. In meeting these goals, RIMFAX will provide a view of the stratigraphic section and a window into the geological and environmental history of Mars. To verify the design an Engineering Model (EM) of the radar was tested in the field in the spring 2017. Different sounding modes on the EM were tested in different types of subsurface geology on Svalbard. Deep soundings were performed on polythermal glaciers down to a couple of hundred meters. Shallow soundings were used to map a ground water table in the firn area of a glacier. A combination of deep and shallow soundings was used to image buried ice under a sedimentary layer of a couple of meters. Subsurface sedimentary layers were imaged down to more than 20 meters in sand stone permafrost. This presentation will give an overview of the RIMFAX investigation, describe the development of the radar system, and show results from field tests of the radar.

Integrity inspection of main access tunnel using ground penetrating radar

Science.gov (United States)

Ismail, M. A.; Abas, A. A.; Arifin, M. H.; Ismail, M. N.; Othman, N. A.; Setu, A.; Ahmad, M. R.; Shah, M. K.; Amin, S.; Sarah, T.

2017-11-01

This paper discusses the Ground Penetrating Radar (GPR) survey performed to determine the integrity of wall of tunnel at a hydroelectric power generation facility. GPR utilises electromagnetic waves that are transmitted into the medium of survey. Any reflectors in the medium will reflect the transmitted waves and picked up by the GPR antenna. The survey was done using MALA GeoScience RAMAC CUII with 250MHz antenna. Survey was done on the left, the crown and the right walls of the underground tunnels. Distance was measured using wheel encoders. The results of the survey is discussed in this paper.

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.

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

International Nuclear Information System (INIS)

Handayani, Gunawan

2015-01-01

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

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.

Investigation of HMA compactability using GPR technique

Science.gov (United States)

Plati, Christina; Georgiou, Panos; Loizos, Andreas

2014-05-01

In-situ field density is often regarded as one of the most important controls used to ensure that an asphalt pavement being placed is of high quality. The achieved density results from the effectiveness of the applied compaction mode on the Hot Mix Asphalt (HMA) layer. It is worthwhile mentioning that the proper compaction of HMA increases pavement fatigue life, decreases the amount of permanent deformation or rutting, reduces the amount of oxidation or aging, decreases moisture damage or stripping, increases strength and internal stability, and may decrease slightly the amount of low-temperature cracking that may occur in the mix. Conventionally, the HMA density in the field is assessed by direct destructive methods, including through the cutting of samples or drilling cores. These methods are characterized by a high accuracy, although they are intrusive and time consuming. In addition, they provide local information, i.e. information only for the exact test location. To overcome these limitations, the use of non-intrusive techniques is often recommended. The Ground Penetrating Radar (GPR) technique is an example of a non-intrusive technique that has been increasingly used for pavement investigations over the years. GPR technology is practical and application-oriented with the overall design concept, as well as the hardware, usually dependent on the target type and the material composing the target and its surroundings. As the sophistication of operating practices increases, the technology matures and GPR becomes an intelligent sensor system. The intelligent sensing deals with the expanded range of GPR applications in pavements such as determining layer thickness, detecting subsurface distresses, estimating moisture content, detecting voids and others. In addition, the practice of using GPR to predict in-situ field density of compacted asphalt mixture material is still under development and research; however the related research findings seem to be promising

Ground penetrating radar evaluation of new pavement density.

Science.gov (United States)

2015-02-01

The objective of this project was to map pavement surface density variations using dielectric : measurements from ground penetrating radar (GPR). The work was carried out as part of an : Asphalt Intelligent Compaction demonstration project on SR 539 ...

Estimating water content in an active landfill with the aid of GPR

Energy Technology Data Exchange (ETDEWEB)

Yochim, April, E-mail: ayochim@regionofwaterloo.ca [Region of Waterloo Waste Management Division, 925 Erb Street West, Waterloo, ON N2J 3Z4 (Canada); Zytner, Richard G., E-mail: rzytner@uoguelph.ca [School of Engineering, University of Guelph, Guelph, ON N1G 2W1 (Canada); McBean, Edward A., E-mail: emcbean@uoguelph.ca [School of Engineering, University of Guelph, Guelph, ON N1G 2W1 (Canada); Endres, Anthony L., E-mail: alendres@sciborg.uwaterloo.ca [Dept. of Earth and Environmental Sciences, University of Waterloo, Waterloo, ON N2L 3G1 (Canada)

2013-10-15

Highlights: • Limited information in the literature on the use of GPR to measure in situ water content in a landfill. • Developed GPR method allows measurement of in situ water content in a landfill. • Developed GPR method is appealing to waste management professionals operating landfills. - Abstract: Landfill gas (LFG) receives a great deal of attention due to both negative and positive environmental impacts, global warming and a green energy source, respectively. However, predicting the quantity of LFG generated at a given landfill, whether active or closed is difficult due to the heterogeneities present in waste, and the lack of accurate in situ waste parameters like water content. Accordingly, ground penetrating radar (GPR) was evaluated as a tool for estimating in situ water content. Due to the large degree of subsurface heterogeneity and the electrically conductive clay cap covering landfills, both of which affect the transmission of the electromagnetic pulses, there is much scepticism concerning the use of GPR to quantify in situ water content within a municipal landfill. Two landfills were studied. The first landfill was used to develop the measurement protocols, while the second landfill provided a means of confirming these protocols. GPR measurements were initially completed using the surface GPR approach, but the lack of success led to the use of borehole (BH) GPR. Both zero offset profiling (ZOP) and multiple offset gathers (MOG) modes were tried, with the results indicating that BH GPR using the ZOP mode is the most simple and efficient method to measure in situ water content. The best results were obtained at a separation distance of 2 m, where higher the water content, smaller the effective separation distance. However, an increase in water content did appear to increase the accuracy of the GPR measurements. For the effective separation distance of 2 m at both landfills, the difference between GPR and lab measured water contents were reasonable

Estimating water content in an active landfill with the aid of GPR

International Nuclear Information System (INIS)

Yochim, April; Zytner, Richard G.; McBean, Edward A.; Endres, Anthony L.

2013-01-01

Highlights: • Limited information in the literature on the use of GPR to measure in situ water content in a landfill. • Developed GPR method allows measurement of in situ water content in a landfill. • Developed GPR method is appealing to waste management professionals operating landfills. - Abstract: Landfill gas (LFG) receives a great deal of attention due to both negative and positive environmental impacts, global warming and a green energy source, respectively. However, predicting the quantity of LFG generated at a given landfill, whether active or closed is difficult due to the heterogeneities present in waste, and the lack of accurate in situ waste parameters like water content. Accordingly, ground penetrating radar (GPR) was evaluated as a tool for estimating in situ water content. Due to the large degree of subsurface heterogeneity and the electrically conductive clay cap covering landfills, both of which affect the transmission of the electromagnetic pulses, there is much scepticism concerning the use of GPR to quantify in situ water content within a municipal landfill. Two landfills were studied. The first landfill was used to develop the measurement protocols, while the second landfill provided a means of confirming these protocols. GPR measurements were initially completed using the surface GPR approach, but the lack of success led to the use of borehole (BH) GPR. Both zero offset profiling (ZOP) and multiple offset gathers (MOG) modes were tried, with the results indicating that BH GPR using the ZOP mode is the most simple and efficient method to measure in situ water content. The best results were obtained at a separation distance of 2 m, where higher the water content, smaller the effective separation distance. However, an increase in water content did appear to increase the accuracy of the GPR measurements. For the effective separation distance of 2 m at both landfills, the difference between GPR and lab measured water contents were reasonable

Estimation of soil hydraulic parameters in the field by integrated hydrogeophysical inversion of time-lapse ground-penetrating radar data

KAUST Repository

Jadoon, Khan; Weihermü ller, Lutz; Scharnagl, Benedikt; Kowalsky, Michael B.; Bechtold, Michel; Hubbard, Susan S.; Vereecken, Harry; Lambot, Sé bastien

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

Experimental results from a stepped frequency GPR

Directory of Open Access Journals (Sweden)

G. M. Signore

2003-06-01

Full Text Available In the framework of a nationally funded project, a Ground Penetrating Radar (GPR has been developed by the Italian Consortium for Research on Advanced Remote Sensing Systems (CO.RI.S.T.A.. The system was described in a previous paper (Alberti et al., 2002. As new aspects, the system is a stepped frequency GPR that can work both in gated and ungated mode, and the antennas can be moved automatically in a controlled fashion. As aspects of geophysical interest, the system is exploitable in situations wherein a high resolution and a shallow penetration in the soil (a few meters are required. Possibly, this is an example of probing a landscape. This paper completes the results of Alberti et al. (2002, wherein laboratory tests where described, by providing the main results obtained during an outdoor experimental campaign, performed fi rst in a controlled site and then in an archaeological site.

Bistatic GPR Measurements in the Egyptian Western Desert - Measured and Simulated data

Science.gov (United States)

Ciarletti, V.; Le Gall, A.; Berthelier, J.; Ney, R.; Corbel, C.; Dolon, F.

2006-12-01

The TAPIR (Terrestrial And Planetary Investigation Radar) instrument has been designed at CETP (Centre d'etude des Environnements Terrestre et Planetaires) to explore the deep Martian subsurface (down to a few kilometers) and to detect liquid water reservoirs. TAPIR is an impulse ground penetrating radar operating at central frequencies ranging from 2 to 4 MHz operating from the surface. In November 2005, an updated version of the instrument working either in monostatic or in bi-static mode was tested in the Egyptian Western Desert. The work presented here focuses on the bi-static measurements performed on the Abou Saied plateau which shows a horizontally layered sub-surface. The electromagnetic signal was transmitted using one of the two orthogonal 70 m loaded electrical dipole antennas of the transmitting GPR. A second GPR, 50 or 100 meters apart, was dedicated to the signal reception. The received waves were characterized by a set of 5 measurements performed on the receiving GPR : the two horizontal components of the electric field and the three composants of the magnetic field. They were used to compute the direction of arrival of the incoming waves and to retrieve more accurately their propagation path and especially to discriminate between waves due to some sub-surface reflecting structure and those due to interaction with the surface clutter. A very efficient synchronization between the two radars enabled us to perform coherent additions up to 2^{31} which improves dramatically the obtained signal to noise ratio. Complementary electromagnetic measurements were conducted on the same site by the LPI (Lunar and Planetary Institute) and the SwRI (Southwest Research Institute). They provided independent information which helped the interpretation of the TAPIR data. Accurate simulations obtained by FDTD taking into account the information available are presented and used for both the interpretation of the measured data and the validation of the instrument.

Comparison of PCA and ICA based clutter reduction in GPR systems for anti-personal landmine detection

DEFF Research Database (Denmark)

Karlsen, Brian; Larsen, Jan; Sørensen, Helge Bjarup Dissing

2001-01-01

This paper presents statistical signal processing approaches for clutter reduction in stepped-frequency ground penetrating radar (SF-GPR) data. In particular, we suggest clutter/signal separation techniques based on principal and independent component analysis (PCA/ICA). The approaches...

Detection of Leaks in Water Mains Using Ground Penetrating Radar

OpenAIRE

Alaa Al Hawari; Mohammad Khader; Tarek Zayed; Osama Moselhi

2016-01-01

Ground Penetrating Radar (GPR) is one of the most effective electromagnetic techniques for non-destructive non-invasive subsurface features investigation. Water leak from pipelines is the most common undesirable reason of potable water losses. Rapid detection of such losses is going to enhance the use of the Water Distribution Networks (WDN) and decrease threatens associated with water mains leaks. In this study, GPR approach was developed to detect leaks by implementing an appropriate imagin...

Shallow radar (SHARAD) sounding observations of the Medusae Fossae Formation, Mars

Science.gov (United States)

Carter, L.M.; Campbell, B.A.; Watters, T.R.; Phillips, R.J.; Putzig, N.E.; Safaeinili, A.; Plaut, J.J.; Okubo, C.H.; Egan, A.F.; Seu, R.; Biccari, D.; Orosei, R.

2009-01-01

The SHARAD (shallow radar) sounding radar on the Mars Reconnaissance Orbiter detects subsurface reflections in the eastern and western parts of the Medusae Fossae Formation (MFF). The radar waves penetrate up to 580 m of the MFF and detect clear subsurface interfaces in two locations: west MFF between 150 and 155?? E and east MFF between 209 and 213?? E. Analysis of SHARAD radargrams suggests that the real part of the permittivity is ???3.0, which falls within the range of permittivity values inferred from MARSIS data for thicker parts of the MFF. The SHARAD data cannot uniquely determine the composition of the MFF material, but the low permittivity implies that the upper few hundred meters of the MFF material has a high porosity. One possibility is that the MFF is comprised of low-density welded or interlocked pyroclastic deposits that are capable of sustaining the steep-sided yardangs and ridges seen in imagery. The SHARAD surface echo power across the MFF is low relative to typical martian plains, and completely disappears in parts of the east MFF that correspond to the radar-dark Stealth region. These areas are extremely rough at centimeter to meter scales, and the lack of echo power is most likely due to a combination of surface roughness and a low near-surface permittivity that reduces the echo strength from any locally flat regions. There is also no radar evidence for internal layering in any of the SHARAD data for the MFF, despite the fact that tens-of-meters scale layering is apparent in infrared and visible wavelength images of nearby areas. These interfaces may not be detected in SHARAD data if their permittivity contrasts are low, or if the layers are discontinuous. The lack of closely spaced internal radar reflectors suggests that the MFF is not an equatorial analog to the current martian polar deposits, which show clear evidence of multiple internal layers in SHARAD data. ?? 2008 Elsevier Inc.

Numerical modelling of GPR electromagnetic fields for locating burial sites

Directory of Open Access Journals (Sweden)

Carcione José M.

2017-01-01

Full Text Available Ground-penetrating radar (GPR is commonly used for locating burial sites. In this article, we acquired radargrams at a site where a domestic pig cadaver was buried. The measurements were conducted with the ProEx System GPR manufactured by the Swedish company Mala Geoscience with an antenna of 500MHz. The event corresponding to the pig can be clearly seen in the measurements. In order to improve the interpretation, the electromagnetic field is compared to numerical simulations computed with the pseudo-spectral Fourier method. A geological model has been defined on the basis of assumed electromagnetic properties (permittivity, conductivity and magnetic permeability. The results, when compared with the GPR measurements, show a dissimilar amplitude behaviour, with a stronger reflection event from the bottom of the pit. We have therefore performed another simulation by decreasing the electrical conductivity of the body very close to that of air. The comparison improved, showing more reflections, which could be an indication that the body contains air or has been degraded to a certain extent that the electrical resistivity has greatly increased.

Applying FDEM, ERT and GPR at a site with soil contamination: A case study

Science.gov (United States)

Wang, Tzu-Pin; Chen, Chien-Chih; Tong, Lun-Tao; Chang, Ping-Yu; Chen, Yi-Chieh; Dong, Tien-Hsing; Liu, Hsin-Chang; Lin, Chih-Ping; Yang, Kai-Hsing; Ho, Ching-Jen; Cheng, Shih-Nan

2015-10-01

This study employed the combination of three methods, namely the Frequency Domain Electromagnetic (FDEM), Electrical Resistivity Tomography (ERT) and Ground Penetrating Radar (GPR) to evaluate a heavy-metal contaminated site for both pre- and post-remediation investigations. The main goals were to verify the position and the integrity of the underground storage tanks (UST), and to determine the effectiveness of remediation to ensure no contaminants remained at the site. In general, the GPR survey was effective at locating shallowly buried objects. However, due to the highly conductive nature of the heavy-metal laden sludge, the GPR signals were attenuated severely. Thus, the first attempt to use GPR in the pre-remediation investigation did not achieve the desired results and other methods were deployed. The existence of the UST and the sludge within were confirmed by ERT and the UST shape was mapped by FDEM. The principal remediation scheme was soil replacement by replacing the contaminated soil with clean silt. Based on the distinctive property differences of the contaminated soil and the clean silt, the completion of the remediation was confirmed by the differences between pre-remediation and post-remediation in GPR, ERT and FDEM results.

Reconstruction of the inner structure of small scale mining waste dumps by combining GPR and ERTdata.

Science.gov (United States)

Kniess, Rudolf; Martin, Tina

2015-04-01

Two abandoned small waste dumps in the west of the Harz mountains (Germany) were analysed using ground penetrating radar (GPR) and electrical resistivity tomography (ERT). Aim of the project (ROBEHA, funded by the German Federal Ministry of Education and Research (033R105)) is the assessment of the recycling potential of the mining residues taking into account environmental risks of reworking the dump site. One task of the geophysical prospection is the investigation of the inner structure of the mining dump. This is important for the estimation of the approximate volume of potentially reusable mining deposits within the waste dump. The two investigated dump sites are different in age and therefore differ in their structure. The older residues (mining dumps. The resistivities of the dumped material differ from the bedrock resistivities at both sites. The GPR measurements show near surface layer boundaries down to 3 - 4 m. In consecutive campaigns 100 MHz and 200 MHz antennas were used. The GPR results (layer boundaries) were included into the ERT inversion algorithm to enable more precise and stable resistivity models. This needs some special preprocessing steps. The 3D-Position of every electrode from ERT measurement and the GPR antenna position on the surface require an accuracy of less than 1cm. At some points, the layer boundaries and radar wave velocities can be calibrated with borehole stratigraphic data from a mineralogical drilling campaign. This is important for a precise time-depth conversion of reflectors from GPR measurement. This reflectors were taken from radargram and have been adopted as resistivity boundary in the start model of the geoelectric inversion algorithm.

Ground-penetrating radar observations for estimating the vertical displacement of rotational landslides

OpenAIRE

C. Lissak; O. Maquaire; J.-P. Malet; F. Lavigne; C. Virmoux; C. Gomez; R. Davidson

2014-01-01

The objective of this paper is to demonstrate the applicability of Ground Penetrating Radar (GPR) for monitoring the displacement of slow-moving landslides. GPR data is used to estimate the vertical movement of rotational slides in combination with other surveying techniques. The experimental site is located along the Normandy coast (North East France) here several rotational landslides are continuously affected by a seasonal kinematic pattern (low displacem...

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.

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

KAUST Repository

Jadoon, Khan; Weihermller, Lutz; McCabe, Matthew; Moghadas, Davood; Vereecken, Harry; Lambot, Sbastien

2015-01-01

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.

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.

Resolving Carbonate Platform Geometries on the Island of Bonaire, Caribbean Netherlands through Semi-Automatic GPR Facies Classification

Science.gov (United States)

Bowling, R. D.; Laya, J. C.; Everett, M. E.

2018-05-01

The study of exposed carbonate platforms provides observational constraints on regional tectonics and sea-level history. In this work Miocene-aged carbonate platform units of the Seroe Domi Formation are investigated, on the island of Bonaire, located in the Southern Caribbean. Ground penetrating radar (GPR) was used to probe near-surface structural geometries associated with these lithologies. The single cross-island transect described herein allowed for continuous mapping of geologic structures on kilometer length scales. Numerical analysis was applied to the data in the form of k-means clustering of structure-parallel vectors derived from image structure tensors. This methodology enables radar facies along the survey transect to be semi-automatically mapped. The results provide subsurface evidence to support previous surficial and outcrop observations, and reveal complex stratigraphy within the platform. From the GPR data analysis, progradational clinoform geometries were observed on the northeast side of the island which supports the tectonics and depositional trends of the region. Furthermore, several leeward-side radar facies are identified which correlate to environments of deposition conducive to dolomitization via reflux mechanisms.

GPR identification of voids inside concrete based on the support vector machine algorithm

International Nuclear Information System (INIS)

Xie, Xiongyao; Li, Pan; Qin, Hui; Liu, Lanbo; Nobes, David C

2013-01-01

Voids inside reinforced concrete, which affect structural safety, are identified from ground penetrating radar (GPR) images using a completely automatic method based on the support vector machine (SVM) algorithm. The entire process can be characterized into four steps: (1) the original SVM model is built by training synthetic GPR data generated by finite difference time domain simulation and after data preprocessing, segmentation and feature extraction. (2) The classification accuracy of different kernel functions is compared with the cross-validation method and the penalty factor (c) of the SVM and the coefficient (σ2) of kernel functions are optimized by using the grid algorithm and the genetic algorithm. (3) To test the success of classification, this model is then verified and validated by applying it to another set of synthetic GPR data. The result shows a high success rate for classification. (4) This original classifier model is finally applied to a set of real GPR data to identify and classify voids. The result is less than ideal when compared with its application to synthetic data before the original model is improved. In general, this study shows that the SVM exhibits promising performance in the GPR identification of voids inside reinforced concrete. Nevertheless, the recognition of shape and distribution of voids may need further improvement. (paper)

Data fusion of ultrasound and GPR signals for analysis of historic walls

International Nuclear Information System (INIS)

Salazar, A; Gosalbez, J; Safont, G; Vergara, L

2012-01-01

This paper presents an application of ultrasounds and ground-penetrating radar (GPR) for analysis of historic walls. The objectives are to characterize the deformation of a historic wall under different levels of load weights and to obtain an enhanced image of the wall. A new method that fuses data from ultrasound and GPR traces is proposed which is based on order statistics digital filters. Application results are presented for non destructive testing (NDT) of two replicates of historic ashlars' masonry walls: the first one homogeneous and the second one containing controlled defects such as cracks and nooks. The walls are measured separately using ultrasounds and GPR at different load steps. Time and frequency parameters extracted from the signals and different B-Scans for each of the NDT techniques are obtained. After this, a new fused representation is obtained, which results demonstrate the improvement of characterization and defect detection in historic walls using data fusion.

The Use of Ground Penetrating Radar to extend the Results of Archaeological Excavation

Science.gov (United States)

Utsi, E.

2009-04-01

The condition of the Romano-British archaeological site in Wortley, Gloucestershire, UK is typical of sites of the period in that it has been heavily robbed out since it first fell into disuse. Building materials taken from the site have been re-used over the centuries to construct other local buildings. This makes both preservation of the extant remains and interpretation of the excavation problematic. Following the accidental discovery of the site in the 1980s, a programme of excavation was set in place. This excavation was run as a practical archaeological training school and, as a result, a wide range of archaeological and geophysical techniques were applied to the site. This included the introduction of Ground Penetrating Radar (GPR). The preliminary results of the first GPR used on site were not entirely satisfactory which led to the development of a new radar in the early 1990s, specifically developed for use on archaeological sites. The excavation and GPR results were published in a series of excavation reports [1] [2]. It was not possible to excavate fully for two reasons. Firstly the site crossed present day ownership boundaries and secondly the ownership of the excavation area changed. At this point the excavation was summarily terminated. In 2007, permission was given by the owner of an adjacent property to carry out a GPR survey over their land in order to derive additional information, if possible. An area survey was carried out in May 2007 with reduced transect spacing [3]. The radar data showed similar patterning to that of the original investigation i.e. substantial remains which had been subject to a high degree of post-occupational attrition. Time slices from the radar survey were matched to the principal excavation plans. It proved possible to deduce the full extent of certain partially excavated features, notably the courtyard and bath house. It was also possible to demonstrate that one part of the adjacent property did not contain similar

GPR Detection of Buried Symmetrically Shaped Mine-like Objects using Selective Independent Component Analysis

DEFF Research Database (Denmark)

Karlsen, Brian; Sørensen, Helge Bjarup Dissing; Larsen, Jan

2003-01-01

from small-scale anti-personal (AP) mines to large-scale anti-tank (AT) mines were designed. Large-scale SF-GPR measurements on this series of mine-like objects buried in soil were performed. The SF-GPR data was acquired using a wideband monostatic bow-tie antenna operating in the frequency range 750......This paper addresses the detection of mine-like objects in stepped-frequency ground penetrating radar (SF-GPR) data as a function of object size, object content, and burial depth. The detection approach is based on a Selective Independent Component Analysis (SICA). SICA provides an automatic...... ranking of components, which enables the suppression of clutter, hence extraction of components carrying mine information. The goal of the investigation is to evaluate various time and frequency domain ICA approaches based on SICA. Performance comparison is based on a series of mine-like objects ranging...

GPR surveying of transport infrastructures and buildings; underground utility and void sensing - ongoing activities in Working Group 2 of COST Action TU1208

Science.gov (United States)

Pajewski, Lara; Plati, Christina; Derobert, Xavier

2015-04-01

This work aims at presenting the ongoing research activities carried out in Working Group 2 'GPR surveying of pavements, bridges, tunnels and buildings; underground utility and void sensing' 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 Ground Penetrating Radar (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. Four Working Groups (WGs) carry out the research activities. WG1 focuses on the development of innovative GPR equipment dedicated for civil engineering applications. WG2 deals with the development of guidelines and protocols for the surveying, through the use of a GPR system, of transport infrastructure and buildings, as well as for the sensing of utilities and voids. WG3 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. WG4 is concerned with the use of GPR in fields different from the civil engineering, as well as with the integration of GPR with other non-destructive testing techniques. Each WG includes several Projects. WG2 includes five Projects. Project 2.1 focuses on outlining 'Innovative inspection procedures for effective GPR surveying of critical transport infrastructures (pavements, bridges and tunnels).' Project 2.2 is concerned with the development of 'Innovative inspection procedures for effective GPR surveying of buildings.' Project 2.3 deals with identifying 'Innovative inspection procedures for effective GPR sensing and mapping of underground utilities and voids, with a focus to urban

Differential Absorption Radar: An Emerging Technology for Remote Sounding of Water Vapor Within Clouds

Science.gov (United States)

Lebsock, M. D.; Millan Valle, L. F.; Cooper, K. B.; Siles, J.; Monje, R.

2017-12-01

We present the results of our efforts to build and demonstrate the first Differential Absorption Radar (DAR), which will provide unique capabilities to remotely sound for water vapor within cloudy and precipitating atmospheres. The approach leverages multiple radar channels located near the 183 GHz water vapor absorption feature to simultaneously derive microphysical and water vapor profiles. The DAR technique has the potential to neatly complement existing water vapor sounding techniques such as infrared and microwave sounding and GPS radio occultation. These precisions rival those of existing water vapor remote sensing instruments. The approach works best from above clouds because the water vapor burden and line width increases towards the Earth surface allowing increased sampling from the top-down compared with bottom-up. From an airborne or satellite platform channels can be selected that target either upper-tropospheric or lower-tropospheric clouds. Our theoretical studies suggest that the water vapor concentration can be retrieved to within 1-3 gm-3 and the column integrated water vapor can be retrieved to within 1 kgm-2. The high-frequency radar is only recently enabled by technological advances that have allowed us to demonstrate 0.5 W of continuous power near 183 GHz. We are currently developing an airborne DAR using a Frequency Modulated Continuous Wave (FMCW) architecture with a quasi-optical duplexer providing 80 dB of transmit/receive isolation. A prototype of this instrument recently made the first ever range resolved DAR measurements of humidity out to several hundred meters during a light rain event at JPL. The spectral dependence of the attenuation was in excellent agreement with the predicted attenuation based on nearby weather stations, proving for the first time the feasibility of the concept. A major impediment to implementing DAR is the international regulation of radio-frequency transmissions below 300 GHz. The major roadblocks and potential

A semi-empirical model for the prediction of fouling in railway ballast using GPR

Science.gov (United States)

Bianchini Ciampoli, Luca; Tosti, Fabio; Benedetto, Andrea; Alani, Amir M.; Loizos, Andreas; D'Amico, Fabrizio; Calvi, Alessandro

2016-04-01

The first step in the planning for a renewal of a railway network consists in gathering information, as effectively as possible, about the state of the railway tracks. Nowadays, this activity is mostly carried out by digging trenches at regular intervals along the whole network, to evaluate both geometrical and geotechnical properties of the railway track bed. This involves issues, mainly concerning the invasiveness of the operations, the impacts on the rail traffic, the high costs, and the low levels of significance concerning such discrete data set. Ground-penetrating radar (GPR) can represent a useful technique for overstepping these issues, as it can be directly mounted onto a train crossing the railway, and collect continuous information along the network. This study is aimed at defining an empirical model for the prediction of fouling in railway ballast, by using GPR. With this purpose, a thorough laboratory campaign was implemented within the facilities of Roma Tre University. In more details, a 1.47 m long × 1.47 m wide × 0.48 m height plexiglass framework, accounting for the domain of investigation, was laid over a perfect electric conductor, and filled up with several configuration of railway ballast and fouling material (clayey sand), thereby representing different levels of fouling. Then, the set of fouling configurations was surveyed with several GPR systems. In particular, a ground-coupled multi-channel radar (600 MHz and 1600 MHz center frequency antennas) and three air-launched radar systems (1000 MHz and 2000 MHz center frequency antennas) were employed for surveying the materials. By observing the results both in terms of time and frequency domains, interesting insights are highlighted and an empirical model, relating in particular the shape of the frequency spectrum of the signal and the percentage of fouling characterizing the surveyed material, is finally proposed. Acknowledgement The Authors thank COST, for funding the Action TU1208 "Civil

Examining the information content of time-lapse crosshole GPR data collected under different infiltration conditions to estimate unsaturated soil hydraulic properties

DEFF Research Database (Denmark)

Scholer, M.; Irving, J.; Zibar, Majken Caroline Looms

2013-01-01

Time-lapse geophysical data acquired during transient hydrological experiments are being increasingly employed to estimate subsurface hydraulic properties at the field scale. In particular, crosshole ground-penetrating radar (GPR) data, collected while water infiltrates into the subsurface either...... by natural or artificial means, have been demonstrated in a number of studies to contain valuable information concerning the hydraulic properties of the unsaturated zone. Previous work in this domain has considered a variety of infiltration conditions and different amounts of time-lapse GPR data...... of time-lapse zero-offset-profile (ZOP) GPR traveltime data, collected under three different infiltration conditions, for the estimation of van Genuchten–Mualem (VGM) parameters in a layered subsurface medium. Specifically, we systematically analyze synthetic and field GPR data acquired under natural...

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...... island. We document different standard processing steps which lead to increased signal-to-noise ratio, improved resolution and trustworthy GPR-to-borehole correlation. The GPR signals image the subsurface layering with a vertical resolution of ~ 0.2-0.3 m. The penetration depth of the GPR reflection...... conversion of the reflection profiles. The GPR reflections are correlated with sedimentological facies logs, and we test to which extent it is possible to map the architecture of different sedimentary units of the Rømø barrier island based on joint interpretation of the GPR and core data. Detailed...

Safety in GPR prospecting: a rarely-considered issue

Science.gov (United States)

Persico, Raffaele; Pajewski, Lara; Trela, Christiane; Carrick Utsi, Erica

2016-04-01

Safety issues (of people first of all, but also of the equipment and environment) are rarely considered in Ground-Penetrating Radar (GPR) prospecting and, more in general, in near-surface geophysical prospecting. As is right and fully understandable, the scientific community devotes greatest attention first of all to the theoretical and practical aspects of GPR technique, affecting the quality of attainable results, secondly to the efforts and costs needed to achieve them [1-2]. However, the (luckily) growing GPR market and range of applications make it worth giving serious consideration to safety issues, too. The existing manuals dealing with safety in geophysics are mainly concerned with applications requiring "deep" geophysical prospecting, for example the search for oilfields and other hydrocarbon resources [3]. Near-surface geophysics involves less dangers than deep geophysics, of course. Nevertheless, several accidents have already happened during GPR experimental campaigns. We have personally had critical experiences and collected reliable testimonies concerning occurred problems as mountain sicks, fractures of legs, stomach problems, allergic reactions, encounters with potentially-dangerous animals, and more. We have also noticed that much more attention is usually paid to safety issues during indoor experimental activities (in laboratory), rather than during outdoor fieldworks. For example, the Italian National research Council is conventioned with safety experts who hold periodical seminaries about safety aspects. Having taken part to some of them, to our experience we have never heard a "lecture" devoted to outdoor prospecting. Nowadays, any aspects associated to the use of the technologies should be considered. The increasing sensibility and sense of responsibility towards environmental matters impose GPR end-users to be careful not to damage the environment and also the cultural heritage. Near-surface prospecting should not compromise the flora and

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

NARCIS (Netherlands)

Van Dam, Remke; Nooren, Kees|info:eu-repo/dai/nl/33761430X; Dogan, Mine; Hoek, Wim|info:eu-repo/dai/nl/163819394

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.

Time–frequency analysis of GPR data to investigate the damage of monumental buildings

International Nuclear Information System (INIS)

Leucci, Giovanni; Persico, Raffaele; Masini, Nicola

2012-01-01

The presence of particular microclimatic conditions inside monumental buildings is responsible for bio-deterioration processes. In many cases, efflorescence and moulds are visible on the facades of several monuments of historical importance. In many other cases, the effects of decay processes are not visible, thus making difficult the diagnosis and the consequent setup of effective rehabilitation and preservation interventions, especially in the presence of a complex geometry and/or a large variability of construction materials. In such cases, a valuable contribution could be provided by geophysical methods (such as electrical resistivity, electromagnetic conductivity, ground-penetrating radar (GPR), etc), which have been proved to be successful tools for sub-surface investigation and characterization of historical buildings. In old monumental buildings, the masonry structures frequently exhibit cracks, voids, detachments and high moisture contrasts that can give rise to reflection events in radar signals. However, the complexity of the geometry and the structural heterogeneity that characterize these old structures often make the GPR results difficult to analyse and interpret. In particular, the spatial variation in GPR signal attenuation can provide important information about the electrical properties of the investigated materials that, in turn, can be used to assess the physical parameters associated with damage. In this paper, we propose an approach that analyses the data in the form of ‘frequency maps’ to evidence absorption losses probably linked to higher moisture content. Two real case histories back up the proposed method. (paper)

Combined GPR and ERT exploratory geophysical survey of the Medieval Village of Pancorbo Castle (Burgos, Spain)

Science.gov (United States)

Fernández-Álvarez, José-Paulino; Rubio-Melendi, David; Quirós Castillo, Juan Antonio; González-Quirós, Andrés; Cimadevilla-Fuente, David

2017-09-01

Ground-penetrating Radar (GPR) and Electrical Resistivity Tomography (ERT) have been fruitfully employed for archaeological purposes. An area at the Pancorbo medieval site in Burgos (Spain) has been jointly explored by GPR and ERT in the search for the buried remains of the Pancorbo medieval village. After data collection, quality control and merging, a shallow depth of interest was identified and studied in detail. 3D resistivity simulation, considering sensible geometrical structures of the targets helped discover anomalies present in the area. On the other hand, visual GPR inspection was considerably enhanced by trace energy attribute analysis which provided a plan view of the existing anomalies. Two posterior archaeological excavations have a very good correlation between the identified anomalies and the excavated remains. The survey also provides hints for the continuation of the excavation.

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.

A comparative and combined study of EMIS and GPR detectors by the use of Independent Component Analysis

DEFF Research Database (Denmark)

Morgenstjerne, Axel; Karlsen, Brian; Larsen, Jan

2005-01-01

Independent Component Analysis (ICA) is applied to classify unexploded ordnance (UXO) on laboratory UXO test-field data, acquired by stand-off detection. The data are acquired by an Electromagnetic Induction Spectroscopy (EMIS) metal detector and a ground penetrating radar (GPR) detector. The metal...

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...

Quantifying reinforced concrete bridge deck deterioration using ground penetrating radar

Science.gov (United States)

Martino, Nicole Marie

Bridge decks are deteriorating at an alarming rate due to corrosion of the reinforcing steel, requiring billions of dollars to repair and replace them. Furthermore, the techniques used to assess the decks don't provide enough quantitative information. In recent years, ground penetrating radar (GPR) has been used to quantify deterioration by comparing the rebar reflection amplitudes to technologies serving as ground truth, because there is not an available amplitude threshold to distinguish healthy from corroded areas using only GPR. The goal of this research is to understand the relationship between GPR and deck deterioration, and develop a model to determine deterioration quantities with GPR alone. The beginning of this research determines that not only is the relationship between GPR and rebar corrosion stronger than the relationship between GPR and delaminations, but that the two are exceptionally correlated (90.2% and 86.6%). Next, multiple bridge decks were assessed with GPR and half-cell potential (HCP). Statistical parameters like the mean and skewness were computed for the GPR amplitudes of each deck, and coupled with actual corrosion quantities based on the HCP measurements to form a future bridge deck model that can be used to assess any deck with GPR alone. Finally, in order to understand exactly which component of rebar corrosion (rust, cracking or chloride) attenuates the GPR data, computational modeling was carried out to isolate each variable. The results indicate that chloride is the major contributor to the rebar reflection attenuation, and that computational modeling can be used to accurately simulate GPR attenuation due to chloride.

Development of radio acoustic sounding system (RASS with Gadanki MST radar – first results

Directory of Open Access Journals (Sweden)

T. Tsuda

2008-09-01

Full Text Available 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 obtained. During the RASS observation period of about 18 h on 23–24 July 2006 height profiles of atmospheric virtual temperature were obtained between 1.5 km and 10 km and occasionally up to 14 km. In comparison with the three simultaneous radiosonde launches, RASS derived temperature profiles had the r.m.s. discrepancy of about 1 K, although deviation of the RASS results sometimes appeared when the radial wind velocity was not fully available for the correction of apparent sound speed. This study has successfully demonstrated capability of the RASS application with the Gadanki MST radar, which will be used for continuous monitoring of the temperature profiles in the troposphere and lower stratosphere region in the tropics.

Topographic Correction of GPR Profiles Based on Laser Data

International Nuclear Information System (INIS)

Zhang, Di; Zhong, Ruofei; Li, Jia Cun; Zeng, Fanyang

2014-01-01

Data obtained by GPR (Ground Penetrating Radar) are displayed as a continuous cross-sectional profile. Surface, generally, is not flat. As a result, the image becomes distorted and the depth calculated from the surface no longer represents the true and exact position of electrically distinctive layers and objects in materials. In order to get real geologic cross section, GPR data must be corrected. This is paper discusses a new method using the color point cloud data obtained by a Vehicle-borne laser scanning system to compensate for elevation fluctuate. Elevation profile can be extracted from topographic data of survey site acquired using laser scanner, which can then be used to offset the error of GPR data. Through the discrete points in the survey line, each trace of the profile has its own elevation value showing a vertical difference from the reference profile with maximum elevation, then time shifts value of traces vertical offset versus the reference trace of profile can be obtained. At last, the results of topographic correction for radargrams that look extremely like the real geologic cross section are presented, which allows us to get a better profile interpretation and position of the objects and layers in the subsurface

Disposal of iron tailings in reservoirs: a GPR application

Directory of Open Access Journals (Sweden)

Rachel Jardim Martini

2016-11-01

Full Text Available A large volume of waste is generated by iron mining in Brazil, and the amount has been rapidly increasing. The waste is usually stored in large piles or in reservoirs formed by tailings dams, which occupy large areas in the mining complex. The limitation of natural resources and of new areas for waste disposal has led to change in paradigms. This study therefore aimed to apply a geophysical technique, known as Ground Penetrating Radar (GPR, in order to define sedimentation patterns in the subsurface reservoir created by Diogo's tailings dam in Rio Piracicaba in Minas Gerais, Brazil. To assist the recognition of patterns captured by the GPR, subsurface material samples were collected and analyzed for mineralogical composition, moisture content, electrical conductivity, mineralogical analysis, particle size, X-Ray Diffraction and X-Ray Fluorescence. The results indicated that areas with tailings that had high concentrations of hematite (around 60% in the mineralogical analysis altered the reflection patterns. The presence of water generated some multiple reflections, which were less significant in shallower sites with more waste and more significant in deeper sites with less waste. In general, the application of the GPR was feasible in aquatic environments with rich subsurface hematite deposits.

Extracting Archaeological Feautres from GPR Surveys Conducted with Variable Soil Moisture Conditions

Science.gov (United States)

Morris, I. M.; Glisic, B.; Gonciar, A.

2017-12-01

As a common tool for subsurface archaeological prospection, ground penetrating radar (GPR) is a useful method for increasing the efficiency of archaeological excavations. Archaeological sites are often temporally and financially constrained, therefore having limited ability to reschedule surveys compromised by weather. Furthermore, electromagnetic GPR surveys are especially sensitive to variations in water content, soil type, and site-specific interference. In this work, GPR scans of a partially excavated Roman villa consisting of different construction materials and phases (limestone, andesite, brick) in central Romania are compared. Surveys were conducted with a 500 MHz GPR antenna in both dry (pre-rain event) and wet (post-rain event) conditions. Especially in time or depth slices, wet surveys present additional archaeological features that are not present or clear in the standard dry conditions, while simultaneously masking the clutter present in those scans. When dry, the limestone has a similar dielectric constant to the soil and does not provide enough contrast in electromagnetic properties for strong reflections despite the significant difference in their physical properties. Following precipitation, however, the electromagnetic properties of these two materials is dominated by their respective water content and the contrast is enhanced. For this reason, the wet surveys are particularly necessary for revealing reflections from the limestone features often invisible in dry surveys. GPR surveys conducted in variable environmental conditions provide unique archaeological information, with potential near-surface geophysical applications in nondestructive material characterization and identification.

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

Bayesian Markov-Chain-Monte-Carlo inversion of time-lapse crosshole GPR data to characterize the vadose zone at the Arrenaes Site, Denmark

DEFF Research Database (Denmark)

Scholer, Marie; Irving, James; Zibar, Majken Caroline Looms

2012-01-01

We examined to what extent time-lapse crosshole ground-penetrating radar traveltimes, measured during a forced infiltration experiment at the Arreneas field site in Denmark, could help to quantify vadose zone hydraulic properties and their corresponding uncertainties using a Bayesian Markov...... distributions compared with the corresponding priors, which in turn significantly improves knowledge of soil hydraulic properties. Overall, the results obtained clearly demonstrate the value of the information contained in time-lapse GPR data for characterizing vadose zone dynamics.......-chain-Monte-Carlo inversion approach with different priors. The ground-penetrating radar (GPR) geophysical method has the potential to provide valuable information on the hydraulic properties of the vadose zone because of its strong sensitivity to soil water content. In particular, recent evidence has suggested...

Towards Novel Techniques for Root Phenotyping Using GPR

Science.gov (United States)

Kobylinski, C.; Neely, H.; Everett, M. E.; Hays, D. B.; Lewis, K.

2017-12-01

The ability to phenotype roots in situ would provide information for carbon sequestration potential through increased root mass, possible water-seeking strategies by plants, and generate data for plant breeders. One technique for root phenotyping is to measure differences in soil moisture and use this data to infer root presence or absence. Current technologies for soil moisture detection include electromagnetic induction and neutron moisture meters; however, ground penetrating radar (GPR) has been suggested to monitor root phenotypes. The objective of this study is to use GPR as a novel technique for detecting roots and classifying root phenotypes based on the detection of differences in dielectric permittivity in response to changes in soil water content. The study will be conducted at two sites in Texas: Thrall, TX (Burleson clay) and Lubbock, TX (Olton clay loam). Three root types will be investigated: fibrous (grain sorghum), tap root (cowpea), and mixed (9-species). Data will be collected along a 10 m linear transect in each plot with a PulseEkko GPR bi-static unit operating at a radio frequency of 500 MHz. Additionally, an EM38-MK2 survey will be performed along each transect. Soil surface moisture readings will be collected with a ML3 ThetaProbe soil moisture sensor and a neutron moisture meter will be used to obtain soil moisture measurements down to 1.2 m. Measurements will be collected every two weeks throughout the growing season. Soil properties including particle size distribution, cation exchange capacity, and bulk density will also be measured. GPR's ability to distinguish root types across soils will be assessed.

THE IMAGES OF SUBSURFACE TERTIARY – QUARTENARY DEPOSITS BASED ON GROUND PENETRATING RADAR RECORDS OF SUBI KECIL ISLAND COAST, NATUNA DISTRICT, RIAU ARCHIPELAGO PROVINCE

Directory of Open Access Journals (Sweden)

Kris Budiono

2017-07-01

Full Text Available Subsurface Tertiary to Quaternary deposits from coast of Subi Kecil Island, Natuna Distric, Riau Archipelago Province, were imaged with Ground Penetrating Radar (GPR. The GPR survey was carried out by using GSSI Surveyor III/20 with 270 MHz and 40 MHz of 3200 MLF antennas. GPR data were processed using software GSSI’s RADAN for Windows NT™. The interpretation were done by using the radar facies as a groups of radar reflections. The GPR images of study area can be recoqnized in to several facies such as parallel, sub parallel, chaotic, oblique, mound and reflection-free. The calibration were done with geological data along the coast (cliff and outcrop. Unit A is the uppermost layer which is characterized by continous to non continous pararel reflection, srong reflector and high amplitude and is interpreted as alluvium deposits. Below the unit A is unit B which is characterized by non continous sub parallel, chaotic and mound reflector, strong reflector and high amplitude. Unit C and D (Mio-Oligocene are overlain by unit A and B include chaotic, reflection-free and, locally, discontinuous parallel, oblique mound reflector radar facies, correlatable at the cliff face to massive sands, mostly representing near coastal deposits. These units are bounded by continuous, high amplitude reflections that can be easily correlatable throughout the GPR profiles, serving as important stratigraphic markers. The GPR survey may improve the reconstruction of the depositional environments through the recognition of massive and unconsolidated sand deposits within unit A and B (Holocene. The stratigraphic framework was also improved through the recognition of the discontinuity surface between Units C and D.

Microwave tomography enhanced GPR surveys in Centaur’s Domus, Regio VI of Pompeii, Italy

International Nuclear Information System (INIS)

Catapano, I; Crocco, L; Napoli, R Di; Soldovieri, F; Brancaccio, A; Pesando, F; Aiello, A

2012-01-01

The archaeological area of Pompeii (Naples, Italy) is known worldwide as one of the most remarkable examples of a Roman Empire town, but its origins are prior to the Roman age and there is a huge archeological interest in discovering the history of the forma urbis. With respect to this framework, the paper presents results from microwave tomography enhanced ground penetrating radar (GPR) surveys carried out in the Centaur’s Domus, Regio VI, one of the most ancient housing areas of Pompeii. The GPR prospections aimed at addressing and driving the archeological excavation campaign performed in this area in October 2010. The results of stratigraphic assays are used to assess the reliability of the tomographic images obtained. (paper)

A blind test of nondestructive underground void detection by ground penetrating radar (GPR)

Science.gov (United States)

Lai, Wallace W. L.; Chang, Ray K. W.; Sham, Janet F. C.

2018-02-01

Blind test/experiment is widely adopted in various scientific disciplines like medicine drug testing/clinical trials/psychology, but not popular in nondestructive testing and evaluation (NDTE) nor near-surface geophysics (NSG). This paper introduces a blind test of nondestructive underground void detection in highway/pavement using ground penetrating radar (GPR). Purpose of which is to help the Highways Department (HyD) of the Hong Kong Government to evaluate the feasibility of large-scale and nationwide application, and examine the ability of appropriate service providers to carry out such works. In the past failure case of such NDTE/NSG based on lowest bid price, it is not easy to know which part(s) in SWIMS (S - service provider, i.e. people; W - work procedure; I - instrumentation; M - materials in the complex underground; S - specifications by client) fails, and how it/they fail(s). This work attempts to carry out the blind test by burying fit balls (as voids) under a site with reinforced concrete road and paving block by PolyU team A. The blind test about the void centroid, spread and cover depth was then carried out by PolyU team B without prior information given. Then with this baseline, a marking scheme, acceptance criteria and passing mark were set to test six local commercial service providers, determine their scores and evaluate the performance. A pass is a prerequisite of the award of a service contract of similar nature. In this first attempt of the blind test, results were not satisfactory and it is concluded that 'S-service provider' and 'W-work procedure' amongst SWIMS contributed to most part of the unsatisfactory performance.+

Improvement of the energetic properties of the GPR

Science.gov (United States)

Pochanin, Gennadiy P.; Ruban, Vadim P.; Kholod, Pavlo V.; Shuba, Alexander A.; Pochanin, Alexander G.; Orlenko, Alexander A.

2014-05-01

The necessary condition for the expansion of the impulse Ground Penetrating Radar (GPR) applications is to improve the GPR energy performance for the detection of signals on the background of noise. Digital signal processing techniques allow suppressing the noise largely, but they work only when the GPR is able to register the reflected signals. The majority of the modern GPRs use sampling receivers. They allow recording signals of a very short du- ration. However, very large energy losses are inherent to this method. To improve the signal to noise ratio it is possible to increase the power of the probing signal and to de- crease the noise level of the receiver. In GPR, the transmitting and receiving antennas are usually electrodynamically coupled because they are situated quite close to each other. The sensitive input circuit of the receiver does not allow the excess of the signal amplitude typically more than 1 V. Thus, the increase of the intensity of the probing signal is possible only up to a certain level. To overcome this limitation, it was proposed to design an antenna in such a way that the coupling between the transmitting and receiving sections was absent or minimal. A special method that provided the decoupling below -64 dB was invented (theoretically the isolation is absolute and frequency independent). In order to register as short as possible signals, researchers strive to make sample duration of the sampling converter as short as possible. However, the shorter the sample duration, the smaller the energy of the signal that can be received and the larger the noise. Due to the dispersive absorption of electromagnetic waves in the ground, the high-frequency part of the signal spectrum is attenuated faster than the low-frequency part. It makes no sense to expect the arrival of very short pulses from deep reflectors. Thus, it is possible to increase the duration of the samples at reception of the signals from the deep objects. The authors proposed to

Vision-Based Georeferencing of GPR in Urban Areas

Directory of Open Access Journals (Sweden)

Riccardo Barzaghi

2016-01-01

Full Text Available Ground Penetrating Radar (GPR surveying is widely used to gather accurate knowledge about the geometry and position of underground utilities. The sensor arrays need to be coupled to an accurate positioning system, like a geodetic-grade Global Navigation Satellite System (GNSS device. However, in urban areas this approach is not always feasible because GNSS accuracy can be substantially degraded due to the presence of buildings, trees, tunnels, etc. In this work, a photogrammetric (vision-based method for GPR georeferencing is presented. The method can be summarized in three main steps: tie point extraction from the images acquired during the survey, computation of approximate camera extrinsic parameters and finally a refinement of the parameter estimation using a rigorous implementation of the collinearity equations. A test under operational conditions is described, where accuracy of a few centimeters has been achieved. The results demonstrate that the solution was robust enough for recovering vehicle trajectories even in critical situations, such as poorly textured framed surfaces, short baselines, and low intersection angles.

Multi-offset GPR methods for hyporheic zone investigations

Science.gov (United States)

Brosten, T.R.; Bradford, J.H.; McNamara, J.P.; Gooseff, M.N.; Zarnetske, J.P.; Bowden, W.B.; Johnston, M.E.

2009-01-01

Porosity of stream sediments has a direct effect on hyporheic exchange patterns and rates. Improved estimates of porosity heterogeneity will yield enhanced simulation of hyporheic exchange processes. Ground-penetrating radar (GPR) velocity measurements are strongly controlled by water content thus accurate measures of GPR velocity in saturated sediments provides estimates of porosity beneath stream channels using petrophysical relationships. Imaging the substream system using surface based reflection measurements is particularly challenging due to large velocity gradients that occur at the transition from open water to saturated sediments. The continuous multi-offset method improves the quality of subsurface images through stacking and provides measurements of vertical and lateral velocity distributions. We applied the continuous multi-offset method to stream sites on the North Slope, Alaska and the Sawtooth Mountains near Boise, Idaho, USA. From the continuous multi-offset data, we measure velocity using reflection tomography then estimate water content and porosity using the Topp equation. These values provide detailed measurements for improved stream channel hydraulic and thermal modelling. ?? 2009 European Association of Geoscientists & Engineers.

Material integrity verification radar

International Nuclear Information System (INIS)

Koppenjan, S.K.

1999-01-01

The International Atomic Energy Agency (IAEA) has the need for verification of 'as-built' spent fuel-dry storage containers and other concrete structures. The IAEA has tasked the Special Technologies Laboratory (STL) to fabricate, test, and deploy a stepped-frequency Material Integrity Verification Radar (MIVR) system to nondestructively verify the internal construction of these containers. The MIVR system is based on previously deployed high-frequency, ground penetrating radar (GPR) systems that have been developed by STL for the U.S. Department of Energy (DOE). Whereas GPR technology utilizes microwave radio frequency energy to create subsurface images, MTVR is a variation for which the medium is concrete instead of soil. The purpose is to nondestructively verify the placement of concrete-reinforcing materials, pipes, inner liners, and other attributes of the internal construction. The MIVR system underwent an initial field test on CANDU reactor spent fuel storage canisters at Atomic Energy of Canada Limited (AECL), Chalk River Laboratories, Ontario, Canada, in October 1995. A second field test at the Embalse Nuclear Power Plant in Embalse, Argentina, was completed in May 1996. The DOE GPR also was demonstrated at the site. Data collection and analysis were performed for the Argentine National Board of Nuclear Regulation (ENREN). IAEA and the Brazilian-Argentine Agency for the Control and Accounting of Nuclear Material (ABACC) personnel were present as observers during the test. Reinforcing materials were evident in the color, two-dimensional images produced by the MIVR system. A continuous pattern of reinforcing bars was evident and accurate estimates on the spacing, depth, and size were made. The potential uses for safeguard applications were jointly discussed. The MIVR system, as successfully demonstrated in the two field tests, can be used as a design verification tool for IAEA safeguards. A deployment of MIVR for Design Information Questionnaire (DIQ

High-resolution, real-time mapping of surface soil moisture at the field scale using ground penetrating radar

Science.gov (United States)

Lambot, S.; Minet, J.; Slob, E.; Vereecken, H.; Vanclooster, M.

2008-12-01

Measuring soil surface water content is essential in hydrology and agriculture as this variable controls important key processes of the hydrological cycle such as infiltration, runoff, evaporation, and energy exchanges between the earth and the atmosphere. We present a ground-penetrating radar (GPR) method for automated, high-resolution, real-time mapping of soil surface dielectric permittivity and correlated water content at the field scale. Field scale characterization and monitoring is not only necessary for field scale management applications, but also for unravelling upscaling issues in hydrology and bridging the scale gap between local measurements and remote sensing. In particular, such methods are necessary to validate and improve remote sensing data products. The radar system consists of a vector network analyzer combined with an off-ground, ultra-wideband monostatic horn antenna, thereby setting up a continuous-wave steeped-frequency GPR. Radar signal analysis is based on three-dimensional electromagnetic inverse modelling. The forward model accounts for all antenna effects, antenna-soil interactions, and wave propagation in three-dimensional multilayered media. A fast procedure was developed to evaluate the involved Green's function, resulting from a singular, complex integral. Radar data inversion is focused on the surface reflection in the time domain. The method presents considerable advantages compared to the current surface characterization methods using GPR, namely, the ground wave and common reflection methods. Theoretical analyses were performed, dealing with the effects of electric conductivity on the surface reflection when non-negligible, and on near-surface layering, which may lead to unrealistic values for the surface dielectric permittivity if not properly accounted for. Inversion strategies are proposed. In particular the combination of GPR with electromagnetic induction data appears to be promising to deal with highly conductive soils

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

Ground penetrating radar applied to rebar corrosion inspection

Science.gov (United States)

Eisenmann, David; Margetan, Frank; Chiou, Chien-Ping T.; Roberts, Ron; Wendt, Scott

2013-01-01

In this paper we investigate the use of ground penetrating radar (GPR) to detect corrosion-induced thinning of rebar in concrete bridge structures. We consider a simple pulse/echo amplitude-based inspection, positing that the backscattered response from a thinned rebar will be smaller than the similar response from a fully-intact rebar. Using a commercial 1600-MHz GPR system we demonstrate that, for laboratory specimens, backscattered amplitude measurements can detect a thinning loss of 50% in rebar diameter over a short length. GPR inspections on a highway bridge then identify several rebar with unexpectedly low amplitudes, possibly signaling thinning. To field a practical amplitude-based system for detecting thinned rebar, one must be able to quantify and assess the many factors that can potentially contribute to GPR signal amplitude variations. These include variability arising from the rebar itself (e.g., thinning) and from other factors (concrete properties, antenna orientation and liftoff, etc.). We report on early efforts to model the GPR instrument and the inspection process so as to assess such variability and to optimize inspections. This includes efforts to map the antenna radiation pattern, to predict how backscattered responses will vary with rebar size and location, and to assess detectability improvements via synthetic aperture focusing techniques (SAFT).

GPR applications in Civil Engineering in Spain - state-of-the-art

Science.gov (United States)

Pérez Gracia, Vega; Solla, Mercedes; Santos-Assunçao, Sonia; Lorenzo, Henrique

2014-05-01

assistance to various administrations, public institutions and private companies. What is more, some of the existing private companies have also minor test sites to analyze the behavior of the signal and its propagation depending on the type of asphalt concrete. GPR is used mainly in detection of pipes and urban services and various private companies are specialized in these tasks. Another widespread application is archaeological survey; one private company is also specialized in archaeology evaluations, using GPR combined with magnetometer. Forensic examinations are also common applications in Spain. Other less common applications are: regular inspection of roads, bridges and tunnels, cultural heritage buildings assessment, shallow geology studies and quality control in civil engineering. Acknowledgment The study is a contribution to the EU funded COST Action TU1208, "Civil Engineering Applications of Ground Penetrating Radar".

Characterizing Watersheds with Geophysical Methods: Some uses of GPR and EMI in Hydropedological Investigations.

Science.gov (United States)

Doolittle, J.; Lin, H.; Jenkinson, B.; Zhou, X.

2006-05-01

The USDA-NRCS and its cooperators use ground-penetrating radar (GPR) and electromagnetic induction (EMI) as rapid, noninvasive tools to support soil surveys at different scales and levels of resolution. The effective use of GPR is site-specific and generally restricted to soils having low electrical conductivity (e.g., soils with low clay and soluble salt contents). In suitable soils, GPR provides high resolution data, which are used to estimate depths to soil horizons and geologic layers that restrict, redirect, and/or concentrate the flow of water through landscapes. In areas of coarse-textured soils, GPR has been used to map spatiotemporal variations in water-table depths and local ground-water flow patterns. Compared with GPR, EMI can be effectively used across a broader spectrum of soils and spatial scales, but provides lower resolution of subsurface features. EMI is used to refine and improve soil maps prepared with traditional soil survey methods. Differences in apparent conductivity (ECa) are associated with different soils and soil properties (e.g., clay, moisture and soluble salt contents). Apparent conductivity maps provide an additional layer of information, which directs soil sampling, aids the identification and delineation of some soil polygons, and enhances the quality of soil maps. More recently, these tools were used to characterize the hydropedological character of a small, steeply sloping, forested watershed. Within the watershed, EMI was used to characterize the principal soil-landscape components, and GPR was used to provide high resolution data on soil depth and layering within colluvial deposits located in swales and depressional areas.

Identification of buried victims in natural disaster with GPR method

Science.gov (United States)

Dewi, Rianty Kusuma; Kurniawan, Adityo; Taqwantara, Reyhan Fariz; Iskandar, Farras M.; Naufal, Taufiq Ziyan; Widodo

2017-07-01

Indonesian is one of the most seismically active regions in the world and has very complicated plate convergence because there is meeting point of several tectonic plates. The complexity of tectonic features causes a lot of natural disasters such as landslides, tsunamis, earth quakes, volcanoes eruption, etc. Sometimes, the disasters occurs in high populated area and causing thousands to millions of victim been buried under the rumble. Unfortunately, the evacuation still uses the conventional method such using rescue dogs whereas the sensitivity of smell is decrease when the victims buried under the level of the ground. The purpose of this study is to detect buried bodies using GPR method, so it can enhance the effectiveness and the efficiency in looking for the disaster victims. GPR method is used because it can investigate things under the ground. A detailed GPR research has been done in Cikutra Graveyard, Bandung, with corpse buried two week until two years before the research. The radar profiles from this research showed amplitude contras anomaly between the new corpse and the old ones. We obtained the amplitude contras at 1.2-1.4 meters under the surface. This method proved to be effective but still need more attention on undulated surface and non-soil areas.

Seasonal GPR Signal Changes in Two Contrasting Soils in the Shale Hills Catchment

Science.gov (United States)

Lin, H.; Zhang, J.; Doolittle, J. A.

2011-12-01

Repeated GPR surveys in different seasons, combined with real-time soil water monitoring, provide a useful methodology to reveal subsurface hydrologic processes and their underlying mechanisms in different soils and hillslopes. This was demonstrated in the Shale Hills Critical Zone Observatory using two contrasting soils over several dry and wet seasons. Our results showed that 1) the radar reflection in the BC-C horizon interface in the deep Rushtown soil became clearer as soil became wetter, which was linked to lateral flow above this horizon interface that increased the contrast, and 2) the reflection in the soil-bedrock interface and the weathered-unweathered rock interface in the shallow Weikert soil become intermittent as soil became wetter, which was attributed to non-uniform distribution of water in bedrock fractures that created locally strong contrast, leading to point scatter of GPR reflection. This study shows the optimal time for using GPR to detect soil horizon interfaces, the value of nondestructive mapping of soil-rock moisture distribution patterns, and the possibility of identifying preferential flow pathways in the subsurface.

Characterizing fractures and shear zones in crystalline rock using seismic and GPR methods

Science.gov (United States)

Doetsch, Joseph; Jordi, Claudio; Laaksonlaita, Niko; Gischig, Valentin; Schmelzbach, Cedric; Maurer, Hansruedi

2016-04-01

Understanding the natural or artificially created hydraulic conductivity of a rock mass is critical for the successful exploitation of enhanced geothermal systems (EGS). The hydraulic response of fractured crystalline rock is largely governed by the spatial organization of permeable fractures. Defining the 3D geometry of these fractures and their connectivity is extremely challenging, because fractures can only be observed directly at their intersections with tunnels or boreholes. Borehole-based and tunnel-based ground-penetrating radar (GPR) and seismic measurements have the potential to image fractures and other heterogeneities between and around boreholes and tunnels, and to monitor subtle time-lapse changes in great detail. We present the analysis of data acquired in the Grimsel rock laboratory as part of the In-situ Stimulation and Circulation (ISC) experiment, in which a series of stimulation experiments have been and will be performed. The experiments in the granitic rock range from hydraulic fracturing to controlled fault-slip experiments. The aim is to obtain a better understanding of coupled seismo-hydro-mechanical processes associated with high-pressure fluid injections in crystalline rocks and their impact on permeability creation and enhancement. GPR and seismic data have been recorded to improve the geological model and characterize permeable fractures and shear zones. The acquired and processed data include reflection GPR profiles measured from tunnel walls, single-borehole GPR images, and borehole-to-borehole and tunnel-to-tunnel seismic and GPR tomograms. The reflection GPR data reveal the geometry of shear zones up to a distance of 30 m from the tunnels and boreholes, but the interpretation is complicated by the geometrical ambiguity around tunnels and boreholes and by spurious reflections from man-made structures such as boreholes. The GPR and seismic traveltime tomography results reveal brittle fractured rock between two ductile shear zones. The

Combined application of GPR and ERT for the assessment of a wall structure at the Heptapyrgion fortress (Thessaloniki, Greece)

Science.gov (United States)

Angelis, Dimitrios; Tsourlos, Panagiotis; Tsokas, Gregory; Vargemezis, George; Zacharopoulou, Georgia; Power, Christopher

2018-05-01

Non-destructive investigation of monuments can be an extremely valuable tool to evaluate potential structural defects and assist in developing any restoration plans. In this work, both Ground Penetrating Radar (GPR) and Electrical Resistivity Tomography (ERT) techniques were applied to a tower wall of the Heptapyrgion fortress located in Thessaloniki, Greece, which was facing significant moisture problems. GPR cross sections, mainly obtained with a 500 MHz centre frequency antenna, and ERT profiles were collected along the same survey grid on the tower wall. The gprMax numerical solver was used for the GPR forward modelling. In addition, an auxiliary program was used to design and import into gprMax complicated structures and this allowed to simulate more realistically the wall defects and moisture. The GPR simulator was used to assess and optimize the field data acquisition and processing parameters, and to assist in interpreting the GPR cross sections. The ERT sections were inverted as individual 2D lines and also, as a full 3D dataset. The final GPR and ERT data were jointly interpreted in view of the studied problem as results of both methods are highly correlated. A high moisture content area at the eastern part of the wall was identified in both GPR and ERT data, along with the interface between different phases of construction. Through the GPR data we were also able to delineate possible structural defects (cracks, small voids) which was not possible with just using the ERT data. Furthermore, a very good matching was evident between the simulated GPR modelling results incorporating field-interpreted features, and the actual field GPR results, thereby validating the proposed data interpretation. The overall survey and modelling approach produces results that are in a very good agreement between them and proved very useful in accessing the wall structure.

Inverse scattering and GPR data processing: an Introduction

Science.gov (United States)

Persico, Raffaele

2014-05-01

Inverse scattering and GPR data processing: an Introduction Raffaele Persico This abstract is meant to propose a brief overview of the book "Introduction to Ground Penetrating Radar: Inverse scattering and data processing", edited by Wiley Press (ISBN 9781118305003). The reason why I propose this contribution is the fact that, in spite of the large relevant literature, to the best of my knowledge it is not very common to find a text entirely devoted to the physical-mathematical aspects (a part of them, of course) of GPR data processing. Also due to this, probably a sort of gap between the GPR practice and the underlying theory has been created, and indeed we can meet practitioners convinced that the quality of the achieved results is indefinitely improvable by making narrower the spatial step of the data, or that it is desirable to have extremely directive antennas because this would improve the resolution. In order to provide a work hopefully able to address these and other aspects and hopefully able to give a contribution to the correction of these imprecise beliefs, a dealing from the beginning has been proposed, i.e. a sequential, relatively plane, and as much as possible self consistent, dealing starting from the Maxwell's equations and reaching the most commonly exploited migration formulas and linear inversion algorithms, both within a 2D and a 3D framework. This follows the didactic aim to provide to the reader an insight about what can be reasonably achieved and what should be reasonably done in the field and during the processing phase in order to achieve satisfying results. In particular, the reader will be hopefully made aware not only of the mathematical passages, but also of the involved approximations, the needed assumptions and the physical limits of the final algorithms. The results have been also back-upped with numerical exercises and with some experimental tests, all of which conceived on purpose for this text, and some questions with the

Estimation of soil hydraulic parameters by integrated hydrogeophysical inversion of time-lapse GPR data measured at Selhausen, Germany

KAUST Repository

Jadoon, Khan

2012-06-01

We present an integrated hydrogeophysical inversion approach that uses time-lapse off-ground ground-penetrating radar (GPR) data to estimate soil hydraulic parameters, and apply it to a dataset collected in the field. Off-ground GPR data are mainly sensitive to the near-surface water content profile and dynamics, and are thus related to soil hydraulic parameters, such as the parameters of the hydraulic conductivity and water retention functions. The hydrological simulator HYDRUS 1-D was used with a two-layer single- and dual-porosity model. To monitor the soil water content dynamics, time-lapse GPR and time domain reflectometry (TDR) measurements were performed, whereby only GPR data was used in the inversion. The dual porosity model provided better results compared to the single porosity model for describing the soil water dynamics, which is supported by field observations of macropores. Furthermore, the GPR-derived water content profiles reconstructed from the integrated hydrogeophysical inversion were in good agreement with TDR observations. These results suggest that the proposed method is promising for non-invasive characterization of the shallow subsurface hydraulic properties and monitoring water dynamics at the field scale.

A Newly Discovered Antifibrotic Pathway Regulated by Two Fatty Acid Receptors: GPR40 and GPR84.

Science.gov (United States)

Gagnon, Lyne; Leduc, Martin; Thibodeau, Jean-Francois; Zhang, Ming-Zhi; Grouix, Brigitte; Sarra-Bournet, Francois; Gagnon, William; Hince, Kathy; Tremblay, Mikaël; Geerts, Lilianne; Kennedy, Christopher R J; Hébert, Richard L; Gutsol, Alex; Holterman, Chet E; Kamto, Eldjonai; Gervais, Liette; Ouboudinar, Jugurtha; Richard, Jonathan; Felton, Alexandra; Laverdure, Alexandre; Simard, Jean-Christophe; Létourneau, Sylvie; Cloutier, Marie-Pier; Leblond, Francois A; Abbott, Shaun D; Penney, Christopher; Duceppe, Jean-Simon; Zacharie, Boulos; Dupuis, Jocelyn; Calderone, Angelino; Nguyen, Quang T; Harris, Raymond C; Laurin, Pierre

2018-05-01

Numerous clinical conditions can lead to organ fibrosis and functional failure. There is a great need for therapies that could effectively target pathophysiological pathways involved in fibrosis. GPR40 and GPR84 are G protein-coupled receptors with free fatty acid ligands and are associated with metabolic and inflammatory disorders. Although GPR40 and GPR84 are involved in diverse physiological processes, no evidence has demonstrated the relevance of GPR40 and GPR84 in fibrosis pathways. Using PBI-4050 (3-pentylbenzeneacetic acid sodium salt), a synthetic analog of a medium-chain fatty acid that displays agonist and antagonist ligand affinity toward GPR40 and GPR84, respectively, we uncovered an antifibrotic pathway involving these receptors. In experiments using Gpr40- and Gpr84-knockout mice in models of kidney fibrosis (unilateral ureteral obstruction, long-term post-acute ischemic injury, and adenine-induced chronic kidney disease), we found that GPR40 is protective and GPR84 is deleterious in these diseases. Moreover, through binding to GPR40 and GPR84, PBI-4050 significantly attenuated fibrosis in many injury contexts, as evidenced by the antifibrotic activity observed in kidney, liver, heart, lung, pancreas, and skin fibrosis models. Therefore, GPR40 and GPR84 may represent promising molecular targets in fibrosis pathways. We conclude that PBI-4050 is a first-in-class compound that may be effective for managing inflammatory and fibrosis-related diseases. Copyright © 2018 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

GPR applicability to concrete structure inspection - Experiences gained from both experimental studies and workaday measurements

International Nuclear Information System (INIS)

Stainbruch, J.

2009-01-01

During recent years the use of geo-radar (GPR) as a non-destructive technique for examining concrete structures has greatly increased. Though the method is used principally for metallic structural element detection and construction layer thickness determination, its applicability is much wider. GPR is an electromagnetic method working on the principle of transmitting high frequency pulses and analysing their echoes. GPR measurement is performed in reflective mode when transmitting and receiving antennas are towed along the same surface, but it can be used also in trans-illumination mode when transmitter and receiver are on either side of the studied body. In this paper we would like to present the results of our GPR measurements performed on physical models with a known inner structure, as well as the results of 'blind tests' diagnostic measurements of different kinds of real concrete constructions (road bridges and the wall of a water supply tunnel) without any additional information. It is shown that GPR can be used in a wide range of diagnostic applications. Very good results are obtained mainly in the detection of metal objects (for instance reinforcement bars). The detection of other kinds of anomalies depends on the contrast in electrical properties between the object and host media and on sufficient target size compare to wave-length

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

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...

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 me...... metallic and non-metallic objects with a diameter of 54 mm buried in loamy soil....

Design and Implementation of 1-2 GHz Stepped Frequency GPR for Buried Metal Detection

Directory of Open Access Journals (Sweden)

Joko Suryana

2010-10-01

Full Text Available In this paper, we describe the design and realization steps of 1 - 2 GHz SFGPR (Stepped Frequency Ground Penetrating Radar transceiver for metal detection under the ground. Before using prototyped GPR for detecting the metal under the ground, several of calibration processes must be performed, namely phase calibration and monocycle pulse waveform calibration. After completing the calibrations, this prototyped GPR would be ready for detecting a  hidden object such as a metal plate 5 cm under the ground in our small test range size 25 cm x 75 cm x 10 cm. From the calibration and detection results, we concluded that the prototyped SFGPR passed the technical specifications of the design and could perform the metal detection under the ground with high SNR.

In-Situ Measurement of Soil Permittivity at Various Depths for the Calibration and Validation of Low-Frequency SAR Soil Moisture Models by Using GPR

Directory of Open Access Journals (Sweden)

Christian N. Koyama

2017-06-01

Full Text Available At radar frequencies below 2 GHz, the mismatch between the 5 to 15 cm sensing depth of classical time domain reflectometry (TDR probe soil moisture measurements and the radar penetration depth can easily lead to unreliable in situ data. Accurate quantitative measurements of soil water contents at various depths by classical methods are cumbersome and usually highly invasive. We propose an improved method for the estimation of vertical soil moisture profiles from multi-offset ground penetrating radar (GPR data. A semi-automated data acquisition technique allows for very fast and robust measurements in the field. Advanced common mid-point (CMP processing is applied to obtain quantitative estimates of the permittivity and depth of the reflecting soil layers. The method is validated against TDR measurements using data acquired in different environments. Depth and soil moisture contents of the reflecting layers were estimated with root mean square errors (RMSE on the order of 5 cm and 1.9 Vol.-%, respectively. Application of the proposed technique for the validation of synthetic aperture radar (SAR soil moisture estimates is demonstrated based on a case study using airborne L-band data and ground-based P-band data. For the L-band case we found good agreement between the near-surface GPR estimates and extended integral equation model (I2EM based SAR retrievals, comparable to those obtained by TDR. At the P-band, the GPR based method significantly outperformed the TDR method when using soil moisture estimates at depths below 30 cm.

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.

Interpretation of the distortion of ground-penetrating radar propagated and reflected waves - development of a multi-frequency tomography

International Nuclear Information System (INIS)

Hollender, F.

1999-01-01

Within the framework of research for waste disposal in deep geological formations, the French agency for nuclear waste management (ANDRA) has to dispose of non-destructive investigation methods to characterize the medium. Ground penetrating radar (GPR) could be used for this purpose in the case of granitic sites. The work presented here deals with this geophysical method. The classical interpretation of GPR data consists in the localization of geological discontinuities by signal amplitude or arrival time analysis. The main objective of our studies is the interpretation of the radar wave distortion (due to propagation and reflection phenomena), not only to localize discontinuities but also to contribute to their identification. Three preliminary studies have been carried out in order to understand on the one hand, the complexity of the electromagnetic phenomena in the geological medium at radar frequency, and on the other hand, the radar equipment constraints. First, the dispersion and the attenuation characterized by a Q variable factor of the GPR waves are shown with the support of dielectric laboratory measurements. A model, which only requires three parameters, is proposed in order to describe this behavior. Second, the radiation patterns of borehole radar antenna are studied. We show that the amplitude and frequency content of the emitted signal are variable versus the emission angle. An analytical method is proposed to study these phenomena. Finally, instrumental drifts of GPR equipment are studied. Emission time, sampling frequency and amplitude fluctuations are described. These elements are taken into account for the processing of propagated signals by tomographic inversion. Medium anisotropy and borehole trajectory errors are inserted in algorithms in order to cancel artifacts which compromised the previous interpretation. A pre-processing method, based on wave separation algorithm, is applied on data in order to increase tomogram resolution. A new

Electromagnetic modelling, inversion and data-processing techniques for GPR: ongoing activities in Working Group 3 of COST Action TU1208

Science.gov (United States)

Pajewski, Lara; Giannopoulos, Antonis; van der Kruk, Jan

2015-04-01

This work aims at presenting the ongoing research activities carried out in Working Group 3 (WG3) 'EM methods for near-field scattering problems by buried structures; data processing techniques' 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. WG3 is structured in four Projects. Project 3.1 deals with 'Electromagnetic modelling for GPR applications.' Project 3.2 is concerned with 'Inversion and imaging techniques for GPR applications.' The topic of Project 3.3 is the 'Development of intrinsic models for describing near-field antenna effects, including antenna-medium coupling, for improved radar data processing using full-wave inversion.' Project 3.4 focuses on 'Advanced GPR data-processing algorithms.' Electromagnetic modeling tools that are being developed and improved include the Finite-Difference Time-Domain (FDTD) technique and the spectral domain Cylindrical-Wave Approach (CWA). One of the well-known freeware and versatile FDTD simulators is GprMax that enables an improved realistic representation of the soil/material hosting the sought structures and of the GPR antennas. Here, input/output tools are being developed to ease the definition of scenarios and the visualisation of numerical results. The CWA expresses the field scattered by subsurface two-dimensional targets with arbitrary cross-section as a sum of cylindrical waves. In this way, the interaction is taken into account of multiple scattered fields within the medium hosting the sought targets. Recently, the method has been extended to deal with through-the-wall scenarios. One of the

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 independent GPR and geomorphologic data collected across the recent and sub-recent beach ridge deposits. The data analyses include coastal topography, internal dips of beach ridge layers, and sea-level measurements. A clear change in characteristic layer dip is observed between beach face and upper shoreface...

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.

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

Ground penetrating radar images of selected fluvial deposits in the Netherlands

NARCIS (Netherlands)

Berghe, J. van den; Overmeeren, R.A. van

1999-01-01

Ground penetrating radar (GPR) surveys have been carried out in order to characterise reflection patterns and to assess the method's potential for imaging palaeofluvial sediments in the Mass-Rhine former confluence area in the southern Netherlands. The results show that the deposits of meandering,

Ground penetrating radar images of selected fluvial deposits in the Netherlands.

NARCIS (Netherlands)

Vandenberghe, J.; van Overmeeren, R.A.

1999-01-01

Ground penetrating radar (GPR) surveys have been carried out in order to characterise reflection patterns and to assess the method's potential for imaging palaeofluvial sediments in the Mass-Rhine former confluence area in the southern Netherlands. The results show that the deposits of meandering,

Current uses of ground penetrating radar in groundwater-dependent ecosystems research.

Science.gov (United States)

Paz, Catarina; Alcalá, Francisco J; Carvalho, Jorge M; Ribeiro, Luís

2017-10-01

Ground penetrating radar (GPR) is a high-resolution technique widely used in shallow groundwater prospecting. This makes GPR ideal to characterize the hydrogeological functioning of groundwater-dependent ecosystems (GDE). This paper reviews current uses of GPR in GDE research through the construction of a database comprising 91 worldwide GPR case studies selected from the literature and classified according to (1) geological environments favouring GDE; (2) hydrogeological research interests; and (3) field technical and (4) hydrogeological conditions of the survey. The database analysis showed that inland alluvial, colluvial, and glacial formations were the most widely covered geological environments. Water-table depth was the most repeated research interest. By contrast, weathered-marl and crystalline-rock environments as well as the delineation of salinity interfaces in coastal and inland areas were less studied. Despite that shallow groundwater propitiated GDE in almost all the GPR case studies compiled, only one case expressly addressed GDE research. Common ranges of prospecting depth, water-table depth, and volumetric water content deduced by GPR and other techniques were identified. Antenna frequency of 100MHz and the common offset acquisition technique predominated in the database. Most of GPR case studies were in 30-50° N temperate latitudes, mainly in Europe and North America. Eight original radargrams were selected from several GPR profiles performed in 2014 and 2015 to document database classes and identified gaps, as well as to define experimental ranges of operability in GDE environments. The results contribute to the design of proper GPR surveys in GDE research. Copyright © 2017 Elsevier B.V. All rights reserved.

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.

Combining orthogonal polarization for elongated target detection with GPR

International Nuclear Information System (INIS)

Lualdi, Maurizio; Lombardi, Federico

2014-01-01

For an accurate imaging of ground penetrating radar data the polarization characteristics of the propagating electromagnetic (EM) wavefield and wave amplitude variations with antenna pattern orientation must be taken into account. For objects that show some directionality feature and cylindrical shape any misalignment between transmitter and target can strongly modify the polarization state of the backscattered wavefield, thus conditioning the detection capability of the system. Hints on the depolarization can be used to design the optimal GPR antenna survey to avoid omissions and pitfalls during data processing. This research addresses the issue of elongated target detection through a multi azimuth (or multi polarization) approach based on the combination of mutually orthogonal GPR data. Results from the analysis of the formal scattering problem demonstrate how this strategy can reach a scalar formulation of the scattering matrix and achieve a rotational invariant quantity. The effectiveness of the algorithm is then evaluated with a detailed field example showing results closely proximal to those obtained under the optimal alignment condition: detection is significantly improved and the risk of target missing is reduced. (paper)

Clay content evaluation in soils through GPR signal processing

Science.gov (United States)

Tosti, Fabio; Patriarca, Claudio; Slob, Evert; Benedetto, Andrea; Lambot, Sébastien

2013-10-01

The mechanical behavior of soils is partly affected by their clay content, which arises some important issues in many fields of employment, such as civil and environmental engineering, geology, and agriculture. This work focuses on pavement engineering, although the method applies to other fields of interest. Clay content in bearing courses of road pavement frequently causes damages and defects (e.g., cracks, deformations, and ruts). Therefore, the road safety and operability decreases, directly affecting the increase of expected accidents. In this study, different ground-penetrating radar (GPR) methods and techniques were used to non-destructively investigate the clay content in sub-asphalt compacted soils. Experimental layout provided the use of typical road materials, employed for road bearing courses construction. Three types of soils classified by the American Association of State Highway and Transportation Officials (AASHTO) as A1, A2, and A3 were used and adequately compacted in electrically and hydraulically isolated test boxes. Percentages of bentonite clay were gradually added, ranging from 2% to 25% by weight. Analyses were carried out for each clay content using two different GPR instruments. A pulse radar with ground-coupled antennae at 500 MHz centre frequency and a vector network analyzer spanning the 1-3 GHz frequency range were used. Signals were processed in both time and frequency domains, and the consistency of results was validated by the Rayleigh scattering method, the full-waveform inversion, and the signal picking techniques. Promising results were obtained for the detection of clay content affecting the bearing capacity of sub-asphalt layers.

A novel method to remove GPR background noise based on the similarity of non-neighboring regions

Science.gov (United States)

Montiel-Zafra, V.; Canadas-Quesada, F. J.; Vera-Candeas, P.; Ruiz-Reyes, N.; Rey, J.; Martinez, J.

2017-09-01

Ground penetrating radar (GPR) is a non-destructive technique that has been widely used in many areas of research, such as landmine detection or subsurface anomalies, where it is required to locate targets embedded within a background medium. One of the major challenges in the research of GPR data remains the improvement of the image quality of stone materials by means of detection of true anisotropies since most of the errors are caused by an incorrect interpretation by the users. However, it is complicated due to the interference of the horizontal background noise, e.g., the air-ground interface, that reduces the high-resolution quality of radargrams. Thus, weak or deep anisotropies are often masked by this type of noise. In order to remove the background noise obtained by GPR, this work proposes a novel background removal method assuming that the horizontal noise shows repetitive two-dimensional regions along the movement of the GPR antenna. Specifically, the proposed method, based on the non-local similarity of regions over the distance, computes similarities between different regions of the same depth in order to identify most repetitive regions using a criterion to avoid closer regions. Evaluations are performed using a set of synthetic and real GPR data. Experimental results show that the proposed method obtains promising results compared to the classic background removal techniques and the most recently published background removal methods.

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

This work aims at presenting the main results achieved by Working Group (WG) 3 "Electromagnetic methods for near-field scattering problems by buried structures; data processing techniques" of the COST (European COoperation in Science and Technology) Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar" (www.GPRadar.eu, www.cost.eu). The main objective of the Action, started in April 2013 and ending in October 2017, is to exchange and increase scientific-technical knowledge and experience of Ground Penetrating Radar (GPR) techniques in civil engineering, whilst promoting in Europe the effective use of this safe non-destructive technique. The Action involves more than 150 Institutions from 28 COST Countries, a Cooperating State, 6 Near Neighbour Countries and 6 International Partner Countries. Among the most interesting achievements of WG3, we wish to mention the following ones: (i) A new open-source version of the finite-difference time-domain simulator gprMax was developed and released. The new gprMax is written in Python and includes many advanced features such as anisotropic and dispersive-material modelling, building of realistic heterogeneous objects with rough surfaces, built-in libraries of antenna models, optimisation of parameters based on Taguchi's method - and more. (ii) A new freeware CAD was developed and released, for the construction of two-dimensional gprMax models. This tool also includes scripts easing the execution of gprMax on multi-core machines or network of computers and scripts for a basic plotting of gprMax results. (iii) A series of interesting freeware codes were developed will be released by the end of the Action, implementing differential and integral forward-scattering methods, for the solution of simple electromagnetic problems by buried objects. (iv) An open database of synthetic and experimental GPR radargrams was created, in cooperation with WG2. The idea behind this initiative is to give researchers the

Determining the depth of hydro demolition using Lidar methods.

Science.gov (United States)

2014-02-01

Missouri S&T was contracted to conduct research on the effectiveness of using ground-penetrating radar (GPR) to assess several : highway bridges in rural Missouri. The assessment was to be based on the principle that sound concrete has a different de...

Investigating the internal structure of four Azorean Sphagnum bogs using ground-penetrating radar

Directory of Open Access Journals (Sweden)

D. Pereira

2017-08-01

Full Text Available This study evaluates the applicability of ground penetrating radar (GPR as a technique for determining the thickness and internal structure of four peat deposits on Terceira Island (Azores archipelago, mid-Atlantic region. The peatlands studied are all Sphagnum mires located above 500 m a.s.l., but they differ hydrogenetically and in their degree of naturalness. Radargrams for all four bogs, obtained using both 100 MHz and 500 MHz GPR antennae, are presented and compared. The radargram data were validated against peat characteristics (bulk density, von Post H, US method obtained by direct sampling (‘open cores’ across the whole peat profile at each site. A scheme of ‘soft scoring’ for degree of naturalness (DN of the peatland was developed and used as an additional validation factor. The GPR data were positively correlated with DN, and relationships between GPR data, peat bulk density and degree of humification (H were also found. From the radargrams it was possible to distinguish the interface between the peat and the mineral substratum as well as some of the internal structure of the peat deposit, and thus to derive the total thickness of the peat deposit and (in some cases the thicknesses of its constituent layers. The first evaluation of the propagation velocity of electromagnetic waves in Azorean peat yielded a value of 0.04 m ns-1 for 100 MHz and 500 MHz radar antennae. For one of the study sites, the GPR data were analysed using GIS software to produce tridimensional models and thus to estimate the volumes of peat layers. This type of analysis has potential utility for quantifying some of the ecosystem services provided by peatlands.

Characterization for capillary barriers effects in a sand box test using time-lapsed GPR measurements

Science.gov (United States)

Kuroda, S.; Ishii, N.; Morii, T.

2017-12-01

Capillary barriers have been known as the method to protect subsurface regions against infiltration from soil surface. It is caused by essentially heterogeneous structure in permeability or soil physical property and produce non-uniform infiltration process then, in order to estimate the actual situation of the capillary barrier effect, the site-characterization with imaging technique like geophysical prospecting is effective. In this study, we examine the applicability of GPR to characterization for capillary barriers. We built a sand box with 90x340x90cm in which a thin high-permeable gravel layer was embedded as a capillary barrier. We conducted an infiltration test in the sand box using porous tube array for irrigation. It is expected to lead to non-uniform flow of soil water induced by capillary barrier effects. We monitored this process by various types of GPR measurements, including time-lapsed common offset profiling (COP) with multi- frequency antenna and transmission measurements like cross-borehole radar. At first, we conducted GPR common-offset survey. It could show the depth of capillary barrier in sand box. After that we conducted the infiltration test and GPR monitoring for infiltration process. GPR profiles can detect the wetting front and estimate water content change in the soil layer above the capillary barrier. From spatial change in these results we can estimate the effect of capillary barrier and the zone where the break through occur or not. Based on these results, we will discuss the applicability of GPR for monitoring the phenomena around the capillary barrier of soil. At first, we conducted GPR common-offset survey. It could show the depth of capillary barrier in sand box. After that we conducted the infiltration test and GPR monitoring for infiltration process. GPR profiles can detect the wetting front and estimate water content change in the soil layer above the capillary barrier. From spatial change in these results we can estimate the

First conclusions about results of GPR investigations in the Church of the Assumption of the Blessed Virgin Mary in Kłodzko, Poland

Directory of Open Access Journals (Sweden)

A. Chernov

2018-03-01

Full Text Available The article presents results of a ground penetrating radar (GPR investigation carried out in the Church of the Assumption of the Blessed Virgin Mary in Kłodzko, Poland, dating from the 14th to 16th centuries. Due to the 20th century wars, the current state of knowledge about the history of the church is still poor. Under the floor of the Catholic temple, unknown structures might exist. To verify the presence of underground structures such as crypts and tombs, a GPR survey was carried out in chapels and aisles with 500 and 800 MHz GPR shielded antennas. Numerous anomalies were detected. It was concluded that those under the chapels were caused by the presence of crypts beneath the floor.

Meteorite Impact "Earthquake" Features (Rock Liquefaction, Surface Wave Deformations, Seismites) from Ground Penetrating Radar (GPR) and Geoelectric Complex Resistivity/Induced Polarization (IP) Measurements, Chiemgau (Alpine Foreland, Southeast Germany)

Science.gov (United States)

Ernstson, K.; Poßekel, J.

2017-12-01

Densely spaced GPR and complex resistivity measurements on a 30,000 square meters site in a region of enigmatic sinkhole occurrences in unconsolidated Quaternary sediments have featured unexpected and highlighting results from both a meteorite impact research and an engineering geology point of view. The GPR measurements and a complex resistivity/IP electrical imaging revealed extended subrosion depressions related with a uniformly but in various degrees of intensity deformed loamy and gravelly ground down to at least 10 m depth. Two principle observations could be made from both the GPR high-resolution measurements and the more integrating resistivity and IP soundings with both petrophysical evidences in good complement. Subrosion can be shown to be the result of prominent sandy-gravelly intrusions and extrusions typical of rock liquefaction processes well known to occur during strong earthquakes. Funnel-shaped structures with diameters up to 25 m near the surface and reaching down to the floating ground water level at 10 m depth were measured. GPR radargrams could trace prominent gravelly-material transport bottom-up within the funnels. Seen in both GPR tomography and resistivity/IP sections more or less the whole investigated area is overprinted by wavy deformations of the unconsolidated sediments with wavelengths of the order of 5 - 10 m and amplitudes up to half a meter, likewise down to 10 m depth. Substantial earthquakes are not known in this region. Hence, the observed heavy underground disorder is considered the result of the prominent earthquake shattering that must have occurred during the Holocene (Bronze Age/Celtic era) Chiemgau meteorite impact event that produced a 60 km x 30 km sized crater strewn field directly hosting the investigated site. Depending on depth and size of floating aquifers local concentrations of rock liquefaction and seismic surface waves (probably LOVE waves) to produce the wavy deformations could develop, when the big

Modelling of ground penetrating radar data in stratified media using the reflectivity technique

International Nuclear Information System (INIS)

Sena, Armando R; Sen, Mrinal K; Stoffa, Paul L

2008-01-01

Horizontally layered media are often encountered in shallow exploration geophysics. Ground penetrating radar (GPR) data in these environments can be modelled by techniques that are more efficient than finite difference (FD) or finite element (FE) schemes because the lateral homogeneity of the media allows us to reduce the dependence on the horizontal spatial variables through Fourier transforms on these coordinates. We adapt and implement the invariant embedding or reflectivity technique used to model elastic waves in layered media to model GPR data. The results obtained with the reflectivity and FDTD modelling techniques are in excellent agreement and the effects of the air–soil interface on the radiation pattern are correctly taken into account by the reflectivity technique. Comparison with real wide-angle GPR data shows that the reflectivity technique can satisfactorily reproduce the real GPR data. These results and the computationally efficient characteristics of the reflectivity technique (compared to FD or FE) demonstrate its usefulness in interpretation and possible model-based inversion schemes of GPR data in stratified media

Investigations on the sensitivity of a stepped-frequency radar utilizing a vector network analyzer for Ground Penetrating Radar

Science.gov (United States)

Seyfried, Daniel; Schubert, Karsten; Schoebel, Joerg

2014-12-01

Employing a continuous-wave radar system, with the stepped-frequency radar being one type of this class, all reflections from the environment are present continuously and simultaneously at the receiver. Utilizing such a radar system for Ground Penetrating Radar purposes, antenna cross-talk and ground bounce reflection form an overall dominant signal contribution while reflections from objects buried in the ground are of quite weak amplitude due to attenuation in the ground. This requires a large dynamic range of the receiver which in turn requires high sensitivity of the radar system. In this paper we analyze the sensitivity of our vector network analyzer utilized as stepped-frequency radar system for GPR pipe detection. We furthermore investigate the performance of increasing the sensitivity of the radar by means of appropriate averaging and low-noise pre-amplification of the received signal. It turns out that the improvement in sensitivity actually achievable may differ significantly from theoretical expectations. In addition, we give a descriptive explanation why our appropriate experiments demonstrate that the sensitivity of the receiver is independent of the distance between the target object and the source of dominant signal contribution. Finally, our investigations presented in this paper lead to a preferred setting of operation for our vector network analyzer in order to achieve best detection capability for weak reflection amplitudes, hence making the radar system applicable for Ground Penetrating Radar purposes.

Full 3D Microwave Tomography enhanced GPR surveys: a case study

Science.gov (United States)

Catapano, Ilaria; Soldovieri, Francesco; Affinito, Antonio; Hugenschmidt, Johannes

2014-05-01

Ground Penetrating Radar (GPR) systems are well assessed non-invasive diagnostic tools capable of providing high resolution images of the inner structure of the probed spatial region. Owing to this capability, GPR systems are nowadays more and more considered in the frame of civil engineering surveys since they may give information on constructive details as well as on the aging and risk factors affecting the healthiness of an infrastructure. In this frame, accurate, reliable and easily interpretable images of the probed scenarios are mandatory in order to support the management of maintenance works and assure the safety of structures. Such a requirement motivates the use of different and sophisticated data processing approaches in order to compare more than one image of the same scene, thus improving the reliability and objectiveness of the GPR survey results. Among GPR data processing procedures, Microwave Tomography approaches based on the Born approximation face the imaging as the solution of a linear inverse problem, which is solved by using the Truncated Singular Value Decomposition as a regularized inversion scheme [1]. So far, an approach exploiting a 2D scalar model of the scattering phenomenon have been adopted to process GPR data gathered along a single scan. In this case, 3D images are obtained by interpolating 2D reconstructions (this is referred commonly as pseudo 3D imaging). Such an imaging approach have provided valuable results in several real cases dealing with not only surveys for civil engineering but also archeological prospection, subservice monitoring, security surveys and so on [1-4]. These encouraging results have motivated the development of a full 3D Microwave Tomography approach capable of accounting for the vectorial nature of the wave propagation. The reconstruction capabilities of this novel approach have been assessed mainly against experimental data collected in laboratory controlled conditions. The obtained results corroborate

A compressive sensing-based computational method for the inversion of wide-band ground penetrating radar data

Science.gov (United States)

Gelmini, A.; Gottardi, G.; Moriyama, T.

2017-10-01

This work presents an innovative computational approach for the inversion of wideband ground penetrating radar (GPR) data. The retrieval of the dielectric characteristics of sparse scatterers buried in a lossy soil is performed by combining a multi-task Bayesian compressive sensing (MT-BCS) solver and a frequency hopping (FH) strategy. The developed methodology is able to benefit from the regularization capabilities of the MT-BCS as well as to exploit the multi-chromatic informative content of GPR measurements. A set of numerical results is reported in order to assess the effectiveness of the proposed GPR inverse scattering technique, as well as to compare it to a simpler single-task implementation.

High resolution aquifer characterization using crosshole GPR full-waveform tomography: Comparison with direct-push and tracer test data

Science.gov (United States)

Gueting, Nils; Vienken, Thomas; Klotzsche, Anja; van der Kruk, Jan; Vanderborght, Jan; Caers, Jef; Vereecken, Harry; Englert, Andreas

2017-01-01

Limited knowledge about the spatial distribution of aquifer properties typically constrains our ability to predict subsurface flow and transport. Here we investigate the value of using high resolution full-waveform inversion of cross-borehole ground penetrating radar (GPR) data for aquifer characterization. By stitching together GPR tomograms from multiple adjacent crosshole planes, we are able to image, with a decimeter scale resolution, the dielectric permittivity and electrical conductivity of an alluvial aquifer along cross sections of 50 m length and 10 m depth. A logistic regression model is employed to predict the spatial distribution of lithological facies on the basis of the GPR results. Vertical profiles of porosity and hydraulic conductivity from direct-push, flowmeter and grain size data suggest that the GPR predicted facies classification is meaningful with regard to porosity and hydraulic conductivity, even though the distributions of individual facies show some overlap and the absolute hydraulic conductivities from the different methods (direct-push, flowmeter, grain size) differ up to approximately one order of magnitude. Comparison of the GPR predicted facies architecture with tracer test data suggests that the plume splitting observed in a tracer experiment was caused by a hydraulically low-conductive sand layer with a thickness of only a few decimeters. Because this sand layer is identified by GPR full-waveform inversion but not by conventional GPR ray-based inversion we conclude that the improvement in spatial resolution due to full-waveform inversion is crucial to detect small-scale aquifer structures that are highly relevant for solute transport.

Visual Inspection of Water Leakage from Ground Penetrating Radar Radargram

Science.gov (United States)

Halimshah, N. N.; Yusup, A.; Mat Amin, Z.; Ghazalli, M. D.

2015-10-01

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.

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.

Full-waveform inversion of cross-hole GPR data collected in a strongly heterogeneous chalk reservoir analogue with sharp permittivity and conductivity contrasts

DEFF Research Database (Denmark)

Keskinen, Johanna; Zibar, Majken Caroline Looms; Moreau, Julien

2014-01-01

Chalk sediments form an important reservoir for groundwater onshore and for hydrocarbons in the Danish sector of the North Sea. Cross-hole Ground-penetrating radar (GPR) tomography is an efficient method to investigate subtle porosity variations in the chalk. Traditional ray-based inversion...

a Webgis to Support Gpr 3d Data Acquisition: a First Step for the Integration of Underground Utility Networks in 3d City Models

Science.gov (United States)

Tabarro, P. G.; Pouliot, J.; Fortier, R.; Losier, L.-M.

2017-10-01

For the planning and sustainable development of large cities, it is critical to accurately locate and map, in 3D, existing underground utility networks (UUN) such as pipelines, cables, ducts, and channels. An emerging non-invasive instrument for collecting underground data such as UUN is the ground-penetrating radar (GPR). Although its capabilities, handling GPR and extracting relevant information from its data are not trivial tasks. For instance, both GPR and its complimentary software stack provide very few capabilities to co-visualize GPR collected data and other sources of spatial data such as orthophotography, DEM or road maps. Furthermore, the GPR interface lacks functionalities for adding annotation, editing geometric objects or querying attributes. A new approach to support GPR survey is proposed in this paper. This approach is based on the integration of multiple sources of geospatial datasets and the use of a Web-GIS system and relevant functionalities adapted to interoperable GPR data acquisition. The Web-GIS is developed as an improved module in an existing platform called GVX. The GVX-GPR module provides an interactive visualization of multiple layers of structured spatial data, including GPR profiles. This module offers new features when compared to traditional GPR surveys such as geo-annotated points of interest for identifying spatial clues in the GPR profiles, integration of city contextual data, high definition drone and satellite pictures, as-built, and more. The paper explains the engineering approach used to design and develop the Web GIS and tests for this survey approach, mapping and recording UUN as part of 3D city model.

A WEBGIS TO SUPPORT GPR 3D DATA ACQUISITION: A FIRST STEP FOR THE INTEGRATION OF UNDERGROUND UTILITY NETWORKS IN 3D CITY MODELS

Directory of Open Access Journals (Sweden)

P. G. Tabarro

2017-10-01

Full Text Available For the planning and sustainable development of large cities, it is critical to accurately locate and map, in 3D, existing underground utility networks (UUN such as pipelines, cables, ducts, and channels. An emerging non-invasive instrument for collecting underground data such as UUN is the ground-penetrating radar (GPR. Although its capabilities, handling GPR and extracting relevant information from its data are not trivial tasks. For instance, both GPR and its complimentary software stack provide very few capabilities to co-visualize GPR collected data and other sources of spatial data such as orthophotography, DEM or road maps. Furthermore, the GPR interface lacks functionalities for adding annotation, editing geometric objects or querying attributes. A new approach to support GPR survey is proposed in this paper. This approach is based on the integration of multiple sources of geospatial datasets and the use of a Web-GIS system and relevant functionalities adapted to interoperable GPR data acquisition. The Web-GIS is developed as an improved module in an existing platform called GVX. The GVX-GPR module provides an interactive visualization of multiple layers of structured spatial data, including GPR profiles. This module offers new features when compared to traditional GPR surveys such as geo-annotated points of interest for identifying spatial clues in the GPR profiles, integration of city contextual data, high definition drone and satellite pictures, as-built, and more. The paper explains the engineering approach used to design and develop the Web GIS and tests for this survey approach, mapping and recording UUN as part of 3D city model.

Joint application of ground penetrating radar and electrical resistivity measurements for characterization of subsurface stratigraphy in Southwestern Nigeria

International Nuclear Information System (INIS)

Adepelumi, A A; Fayemi, O

2012-01-01

The frequent building collapses in Nigeria have been attributed to a lack of pre-construction investigations, which assist engineers in obtaining in situ geotechnical information. Further, the structural subsurface settings are often ignored or investigation is haphazardly carried out. To address this issue and demonstrate the importance of such a survey, a combination of ground penetrating radar (GPR) and vertical electrical sounding (VES) data were acquired in a part of Southwestern Nigeria. A 200 MHz antenna was used for the data acquisition along four traverses. The data were subjected to standard GPR processing techniques, and attribute analysis such as instantaneous frequency, amplitude and phase. Also, for comparative and engineering characterization purposes, longitudinal conductance and coefficient of anisotropy were computed from the VES results and used for determining the competency of the bedrocks. From the GPR results, it was observed that the mapped subsurface is characterized as erosional truncated at a low angle, which is southerly dipping and includes tangential reflections. Further, stratified rocks dipping at an angle of 32° occur between 1.0 and 4.5 m depth in all of the GPR sections; these strata were truncated by topsoil at shallow depths. Also, some of the sections depict ancient channel structures that have a dimension of 70 m × 40 m. The resistivity data suggest that the study area is characterized by four distinct geoelectric sequences. These comprise topsoil which is composed of clay-like sand to lateritic clay whose thickness ranges between 0.25 and 8.12 m, weathered bedrock with a thickness between 3.84 and 12.61 m, stratified bedrock with a thickness between 0.33 and 7.51 m, and fresh bedrock. These results reveal a complex subsurface geology and this characterizes the study area. The area has low to moderate longitudinal conductance and coefficient of anisotropy values, which suggest that incompetent to semi-competent bedrock

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...

Ground penetrating radar survey across the Bok Bak fault, Kedah, Malaysia

International Nuclear Information System (INIS)

Yuniarti Ulfa; Nur Fathin Mohd Jamel; Mardiana Samsuardi

2013-01-01

A ground penetrating radar (GPR) survey was done across the Bok Bak Fault zone in Baling, Kedah in order to investigate the shallow subsurface geology of the Bok Bak fault zone, its extension and associated weak zones within the study area. GPR data acquisition was compared with visual inspection on the slope of the outcrop. Ten GPR profiles were acquired using 250 MHz GPR frequency. Basic data processing and filtering to reduce some noise and unwanted signal was done using MALA RAMAC Ground Vision software. The data penetrate around 2 meters in depth for all survey lines. In most lines shows clear images of shallowest Bok Bak Fault (NW trending) as detected at distance of 28 m horizontal marker. It also exhibits several sets of faults as a result of Bok Bak Fault deformation, including the conjugate NE trending fault (Lubok Merbau Fault). Active seismicity encompasses the Malay-Thai Peninsular trigger the changes of Bok Bak Fault dipping direction, steeper dips of conjugate faults and faults or fractures rotational movement. (author)

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

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

Moisture evaluation of wood material using GPR with WARR method - COST Action TU1208

Science.gov (United States)

Reci, Hamza; Sbart'i, Zoubir Mehdi; Pajewski, Lara; Marciniak, Marian

2016-04-01

This work deals with the study of the sensitivity of GPR electromagnetic waves to moisture variation in wood material in relation with the direction of fibers and polarization of Electromagnetic field. The relations between relative permittivity and moisture content and the amplitude attenuation with distance was a target study using the direct waves in Wide Angle Radar Reflection (WARR) configuration. Comparison of results measured with reflected waves and direct waves was of main importance since they have different behavior in relation with moisture variation, due to different path of propagation. This research activity has been carried out during one Short-Term Scientific Missions (STSM) funded by the COST (European Cooperation in Science and Technology) Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar" in November-December 2015. In context of durability evaluation of construction materials, several studies have been carried out by the I2M team, University of Bordeaux, using direct and reflected waves for the evaluation of water content on concrete and wood materials [1-3]. As related to the wood material there is one study carried out using the reflected waves on wood for different humidity and different wood samples, in all the direction of polarization using GPR technique ground coupled antenna at 1.5 GHz [3]. This work continued with different moisture content in order to study the behavior of direct waves as function of moisture. Results taken from those measurements are compared with them from Fixed Offset (reflected method) with one antenna (1.5GHz or 2.6GHz), realized from the previous studies from the I2M and already published [1-3]. The results taken from this work from the reflected waves, show that the effect of wood anisotropy is significant on the variation of relative permittivity with moisture content on wood sample and that is in good agreement with the previous results [3-6]. As related to the direct waves, a small

Influence of Clay Content, Mineralogy and Fabric On Radar Frequency Response of Aquifer Materials

Science.gov (United States)

West, L. J.; Handley, K.

High frequency electromagnetic methods such as ground penetrating radar (GPR) and time domain reflectometry (TDR) are widely employed to measure water saturation in the vadose zone and water filled porosity in the saturated zone. However, previous work has shown that radar frequency dielectric properties are strongly influenced by clay as well as by water content. They have also shown that that the dielectric response of clay minerals is strongly frequency dependent, and that even a small proportion of clay such as that present in many sandstone aquifers can have a large effect at typi- cal GPR frequencies (around 100MHz). Hence accurate water content/porosity deter- mination requires clay type and content to be taken into account. Reported here are dielectric measurements on clay-sand mixtures, aimed at investigating the influence of clay mineralogy, particle shape, and the geometrical arrangement of the mixture constituents on GPR and TDR response. Dielectric permittivity (at 50-1000MHz) was measured for mixtures of Ottawa Sand and various clay minerals or clay size quartz rock flour, using a specially constructed dielectric cell. Both homogeneous and layered mixtures were tested. The influence of pore water salinity, clay type, and particle arrangement on the dielectric response is interpreted in terms of dielectric dispersion mechanisms. The appropriateness of var- ious dielectric mixing rules such as the Complex Refractive Index Method (CRIM) for determination of water content or porosity from field GPR and TDR data are dis- cussed.

MARSIS data and simulation exploited using array databases: PlanetServer/EarthServer for sounding radars

Science.gov (United States)

Cantini, Federico; Pio Rossi, Angelo; Orosei, Roberto; Baumann, Peter; Misev, Dimitar; Oosthoek, Jelmer; Beccati, Alan; Campalani, Piero; Unnithan, Vikram

2014-05-01

MARSIS is an orbital synthetic aperture radar for both ionosphere and subsurface sounding on board ESA's Mars Express (Picardi et al. 2005). It transmits electromagnetic pulses centered at 1.8, 3, 4 or 5 MHz that penetrate below the surface and are reflected by compositional and/or structural discontinuities in the subsurface of Mars. MARSIS data are available as a collection of single orbit data files. The availability of tools for a more effective access to such data would greatly ease data analysis and exploitation by the community of users. For this purpose, we are developing a database built on the raster database management system RasDaMan (e.g. Baumann et al., 1994), to be populated with MARSIS data and integrated in the PlanetServer/EarthServer (e.g. Oosthoek et al., 2013; Rossi et al., this meeting) project. The data (and related metadata) are stored in the db for each frequency used by MARSIS radar. The capability of retrieving data belonging to a certain orbit or to multiple orbit on the base of latitute/longitude boundaries is a key requirement of the db design, allowing, besides the "classical" radargram representation of the data, and in area with sufficiently hight orbit density, a 3D data extraction, subset and analysis of subsurface structures. Moreover the use of the OGC WCPS (Web Coverage Processing Service) standard can allow calculations on database query results for multiple echoes and/or subsets of a certain data product. Because of the low directivity of its dipole antenna, MARSIS receives echoes from portions of the surface of Mars that are distant from nadir and can be mistakenly interpreted as subsurface echoes. For this reason, methods have been developed to simulate surface echoes (e.g. Nouvel et al., 2004), to reveal the true origin of an echo through comparison with instrument data. These simulations are usually time-consuming, and so far have been performed either on a case-by-case basis or in some simplified form. A code for

2.5D far-field diffraction tomography inversion scheme for GPR that takes into account the planar air-soil interface

DEFF Research Database (Denmark)

Meincke, Peter

2001-01-01

A new 2.5D inversion scheme is derived for fixed-offset ground penetrating radar (GPR) that takes into account the planar air-soil interface. The inversion scheme is based upon the first Born approximation and a far-field approximation of the dyadic Green function for a two-layer medium....

Structural monitoring via microwave tomography-enhanced GPR: the Montagnole test site

International Nuclear Information System (INIS)

Catapano, Ilaria; Di Napoli, Rosario; Soldovieri, Francesco; Bavusi, Massimo; Loperte, Antonio; Dumoulin, Jean

2012-01-01

Structural integrity assessment and monitoring of infrastructures are key factors to prevent and manage crisis events (natural disasters, terrorist attacks and so on) and ensure urban safety. This necessity motivates huge interest towards design, optimization and integration of non-invasive remote and in situ diagnostic techniques. In this framework, ground penetrating radar (GPR) is a well-assessed instrumentation, which allows one to attain information on the inner status of man-made structures while avoiding invasive tests. However, despite its potential, a more widespread use of GPR is actually affected by the difficulties in providing highly informative and easily interpretable images as an outcome of the overall diagnostics procedure. This drawback can be mitigated thanks to the use of microwave tomography (MT) as a data processing tool able to enhance the achievable reconstruction capabilities, and several proofs of its effectiveness have been already shown. In this paper, the potential of the MT approach is investigated in the framework of structural monitoring by an experiment carried out in the Montagnole test site in the French Alps, where the progressive damage of a one-scale concrete beam has been monitored thanks to the integration of several electromagnetic sensing techniques. In this framework, the capability of the MT-enhanced GPR strategy is examined with respect to the possibility of providing information about the damage of the rebar grid of the beam. (paper)

Structural monitoring via microwave tomography-enhanced GPR: the Montagnole test site

Science.gov (United States)

Catapano, Ilaria; Di Napoli, Rosario; Soldovieri, Francesco; Bavusi, Massimo; Loperte, Antonio; Dumoulin, Jean

2012-08-01

Structural integrity assessment and monitoring of infrastructures are key factors to prevent and manage crisis events (natural disasters, terrorist attacks and so on) and ensure urban safety. This necessity motivates huge interest towards design, optimization and integration of non-invasive remote and in situ diagnostic techniques. In this framework, ground penetrating radar (GPR) is a well-assessed instrumentation, which allows one to attain information on the inner status of man-made structures while avoiding invasive tests. However, despite its potential, a more widespread use of GPR is actually affected by the difficulties in providing highly informative and easily interpretable images as an outcome of the overall diagnostics procedure. This drawback can be mitigated thanks to the use of microwave tomography (MT) as a data processing tool able to enhance the achievable reconstruction capabilities, and several proofs of its effectiveness have been already shown. In this paper, the potential of the MT approach is investigated in the framework of structural monitoring by an experiment carried out in the Montagnole test site in the French Alps, where the progressive damage of a one-scale concrete beam has been monitored thanks to the integration of several electromagnetic sensing techniques. In this framework, the capability of the MT-enhanced GPR strategy is examined with respect to the possibility of providing information about the damage of the rebar grid of the beam.

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.

subsurface. It has been useful to decipher shallow geomorphic structures having various options to use different antennas for different depth penetration (0-30 m) with higher resolution.   7.2 Principles of GPR  Ground Penetrating Radar (GPR) was invented... about 90m. Flat and plain land is being used, at present, for agriculture (paddy cultivation) practice. Sand dunes are low lying and highly reworked due to social forestry plantation (acacia) activities. 13    7.8.6 Paleo­Lagoon  GPR data shows two...

Monostatic ultra-wideband GPR antenna for through wall detection

Directory of Open Access Journals (Sweden)

Ali Jawad

2017-01-01

Full Text Available The aim of this paper is to present a monostatic arc-shaped ultra-wideband (UWB printed monopole antenna system with 3-16 GHz frequency bandwidth suitable for through-wall detection. Ground penetrating radar (GPR technique is used for detection with the gain of 6.2 dB achieved for the proposed antenna using defected ground structure (DGS method. To serve the purpose, a simulation experiment of through-wall detection model is constructed which consists of a monostatic antenna act as transmitter and receiver, concrete wall and human skin model. The time domain reflection of obtained result is then analysed for target detection.

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.

An improved interface to process GPR data by means of microwave tomography

Science.gov (United States)

Catapano, Ilaria; Affinito, Antonio; Soldovieri, Francesco

2015-04-01

Ground Penetrating Radar (GPR) systems are well assessed non-invasive diagnostic tools, which are worth being considered in civil engineering surveys since they allow to gather information on constructive materials and techniques of manmade structures as well as on the aging and risk factors affecting their healthiness. However, the practical use of GPR depends strictly on the availability of data processing tools, on one hand, capable of providing reliable and easily interpretable images of the probed scenarios and, on the other side, easy to be used by not expert users. In this frame, 2D and full 3D microwave tomographic approaches based on the Born approximation have been developed and proved to be effective in several practical conditions [1, 2]. Generally speaking, a GPR data processing chain exploiting microwave tomography is made by two main steps: the pre-processing and the data inversion. The pre-processing groups standard procedures like start time correction, muting and background removal, which are performed in time domain to remove the direct antennas coupling, to reduce noise and to improve the targets footprint. The data inversion faces the imaging as the solution of a linear inverse scattering problem in the frequency domain. Hence, a linear integral equation relating the scattered field (i.e. the data) to the unknown electric contrast function is solved by using the truncated Singular Value Decomposition (SVD) as a regularized inversion scheme. Pre-processing and the data inversion are linked by a Discrete Fourier Transform (DFT), which allows to pass from the time domain to the frequency domain. In this respect, a frequency analysis of the GPR signals (traces) is also performed to identify the actual frequency range of the data. Unfortunately, the adoption of microwave tomography is strongly subjected to the involvement of expert people capable of managing properly the processing chain. To overcome this drawback, a couple of years ago, an end

Preprocessing of A-scan GPR data based on energy features

Science.gov (United States)

Dogan, Mesut; Turhan-Sayan, Gonul

2016-05-01

There is an increasing demand for noninvasive real-time detection and classification of buried objects in various civil and military applications. The problem of detection and annihilation of landmines is particularly important due to strong safety concerns. The requirement for a fast real-time decision process is as important as the requirements for high detection rates and low false alarm rates. In this paper, we introduce and demonstrate a computationally simple, timeefficient, energy-based preprocessing approach that can be used in ground penetrating radar (GPR) applications to eliminate reflections from the air-ground boundary and to locate the buried objects, simultaneously, at one easy step. The instantaneous power signals, the total energy values and the cumulative energy curves are extracted from the A-scan GPR data. The cumulative energy curves, in particular, are shown to be useful to detect the presence and location of buried objects in a fast and simple way while preserving the spectral content of the original A-scan data for further steps of physics-based target classification. The proposed method is demonstrated using the GPR data collected at the facilities of IPA Defense, Ankara at outdoor test lanes. Cylindrically shaped plastic containers were buried in fine-medium sand to simulate buried landmines. These plastic containers were half-filled by ammonium nitrate including metal pins. Results of this pilot study are demonstrated to be highly promising to motivate further research for the use of energy-based preprocessing features in landmine detection problem.

GPR attenuation analyses using spectral ratios of primary and multiple arrivals: examples from Welsh peat bogs

Science.gov (United States)

Booth, A.; Carless, D.; Kulessa, B.

2014-12-01

Ground penetrating radar (GPR) is widely applied to qualitative and quantitative interpretation of near-surface targets. Surface deployments of GPR most widely characterise physical properties in terms of some measure of GPR wavelet velocity. Wavelet amplitude is less-often considered, potentially due to difficulties in measuring this quantity: amplitudes are distorted by the anisotropic radiation pattern of antennas, and the ringy GPR wavelet can make successive events difficult to isolate. However, amplitude loss attributes could provide a useful means of estimating the physical properties of a target. GPR energy loss is described by the bandwidth-limited quality factor Q* which, for low-loss media, is proportional to the ratio of dielectric permittivity, ɛ, and electrical conductivity, σ. Comparing the frequency content of two arrivals yields an estimate of interval Q*, but only if they are sufficiently distinct. There may be sufficient separation between a primary reflection and its long-path multiple (i.e. a 'repeat path' of the primary reflection) therefore a dataset that is rich in multiples may be suitable for robust Q* analysis. The Q* between a primary and multiple arrival describes all frequency-dependent loss mechanisms in the interval between the free-surface and the multiple-generating horizon: assuming that all reflectivity is frequency-independent, Q* can be used to estimate ɛ and/or σ. We measure Q* according to the spectral ratio method, for synthetic and real GPR datasets. Our simulations are performed using the finite-difference algorithm GprMax, and represent our example data of GPR acquisitions over peat bogs. These data are a series of 100 MHz GPR acquisitions over sites in the Brecon Beacons National Park of South Wales. The base of the bogs (the basal peat/mineral soil contact) is often a strong multiple-generating horizon. As an example, data from Waun Ddu bog show these events lagging by ~75 ns: GPR velocity is measured here at 0

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

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.

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.

Application of ground-penetrating radar at McMurdo Station, Antarctica

International Nuclear Information System (INIS)

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

Ground penetrating radar documents short-term near-surface hydrological changes around Old Faithful Geyser, Yellowstone National Park, USA

Science.gov (United States)

Lynne, Bridget Y.; Heasler, Henry; Jaworowski, Cheryl; Smith, Gary J.; Smith, Isaac J.; Foley, Duncan

2018-04-01

In April 2015, Ground Penetrating Radar (GPR) was used to characterize the shallow subsurface (images were collected between two eruptions of Old Faithful Geyser. Each set of time-sequence GPR recordings consisted of four transects aligned to provide coverage near the potential location of the inferred 15 m deep geyser chamber. However, the deepest penetration we could achieve with a 200 MHz GPR antennae was 5 m. Seven time-sequence events were collected over a 48-minute interval to image changes in the near-surface, during pre- and post-eruptive cycles. Time-sequence GPR images revealed a series of possible micro-fractures in a highly porous siliceous sinter in the near-surface that fill and drain repetitively, immediately after an eruption and during the recharge period prior to the next main eruptive event.

Radio thermal sounding of natural environments

Science.gov (United States)

Gauss, Martin; Lomukhin, Yuriy

2017-11-01

At the moment, methods of sounding a status of soil, plant, forest and aquatic environments using radiometry and radar methods are intensively used. The main source of information using radar sounding is the back reflection ratio. The radiometric method is used for detection of the brightness temperature. In this paper, a communication between the back reflection ratio and the brightness temperature is described. This communication is proportional.

Nondestructive Evaluation of Concrete Bridge Decks with Automated Acoustic Scanning System and Ground Penetrating Radar.

Science.gov (United States)

Sun, Hongbin; Pashoutani, Sepehr; Zhu, Jinying

2018-06-16

Delamanintions and reinforcement corrosion are two common problems in concrete bridge decks. No single nondestructive testing method (NDT) is able to provide comprehensive characterization of these defects. In this work, two NDT methods, acoustic scanning and Ground Penetrating Radar (GPR), were used to image a straight concrete bridge deck and a curved intersection ramp bridge. An acoustic scanning system has been developed for rapid delamination mapping. The system consists of metal-ball excitation sources, air-coupled sensors, and a GPS positioning system. The acoustic scanning results are presented as a two-dimensional image that is based on the energy map in the frequency range of 0.5⁻5 kHz. The GPR scanning results are expressed as the GPR signal attenuation map to characterize concrete deterioration and reinforcement corrosion. Signal processing algorithms for both methods are discussed. Delamination maps from the acoustic scanning are compared with deterioration maps from the GPR scanning on both bridges. The results demonstrate that combining the acoustic and GPR scanning results will provide a complementary and comprehensive evaluation of concrete bridge decks.

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.

Determination, by using GPR, of the volumetric water content in structures, sub-structures, foundations and soil - ongoing activities in Working Project 2.5 of COST Action TU1208

Science.gov (United States)

Tosti, Fabio; Slob, Evert

2015-04-01

This work will endeavour to review the current status of research activities carried out in Working Project 2.5 'Determination, by using GPR, of the volumetric water content in structures, sub-structures, foundations and soil' within the framework of Working Group 2 'GPR surveying of pavements, bridges, tunnels and buildings; underground utility and void sensing' of the COST (European COoperation in Science and Technology) Action TU1208 'Civil Engineering Applications of Ground Penetrating Radar' (www.GPRadar.eu). Overall, the Project includes 55 Participants from over 21 countries representing 33 Institutions. By considering the type of Institution, a percentage of 64% (35 units) comes from the academic world, while Research Centres and Companies include, respectively, the 27% (15 units) and 9% (5 units) of Institutions. Geographically speaking, Europe is the continent most represented with 18 out of 21 countries, followed by Africa (2 countries) and Asia (1 country). In more details and according to the Europe sub-regions classification provided by the United Nations, Southern Europe includes 39% of countries, Western Europe 27%, while Northern and Eastern Europe are equally present with 17% of countries each. Relying on the main purpose of Working Project 2.5, namely, the ground-penetrating radar-based evaluation of volumetric water content in structures, substructures , foundations, and soils, four main issues have been overall addressed over the first two years of activities. The first one, has been related to provide a comprehensive state of the art on the topic, due to the wide-ranging applications covered in the main disciplines of civil engineering, differently demanding. In this regard, two main publications reviewing the state of the art have been produced [1,2]. Secondly, discussions among Working Group Chairs and other Working Project Leaders have been undertaken and encouraged to avoid the risk of overlapping amongst similar topics from other Working

Lunar ground penetrating radar: Minimizing potential data artifacts caused by signal interaction with a rover body

Science.gov (United States)

Angelopoulos, Michael; Redman, David; Pollard, Wayne H.; Haltigin, Timothy W.; Dietrich, Peter

2014-11-01

Ground-penetrating radar (GPR) is the leading geophysical candidate technology for future lunar missions aimed at mapping shallow stratigraphy (lunar materials, as well as its small size and lightweight components, make it a very attractive option from both a scientific and engineering perspective. However, the interaction between a GPR signal and the rover body is poorly understood and must be investigated prior to a space mission. In doing so, engineering and survey design strategies should be developed to enhance GPR performance in the context of the scientific question being asked. This paper explores the effects of a rover (simulated with a vertical metal plate) on GPR results for a range of heights above the surface and antenna configurations at two sites: (i) a standard GPR testing site with targets of known position, size, and material properties, and; (ii) a frozen lake for surface reflectivity experiments. Our results demonstrate that the GPR antenna configuration is a key variable dictating instrument design, with the XX polarization considered optimal for minimizing data artifact generation. These findings could thus be used to help guide design requirements for an eventual flight instrument.

Precast concrete unit assessment through GPR survey and FDTD modelling

Science.gov (United States)

Campo, Davide

2017-04-01

Precast concrete elements are widely used within United Kingdom house building offering ease in assembly and added values as structural integrity, sound and thermal insulation; most common concrete components include walls, beams, floors, panels, lintels, stairs, etc. The lack of respect of the manufacturer instruction during assembling, however, may induce cracking and short/long term loss of bearing capacity. GPR is a well-established not destructive technique employed in the assessment of structural elements because of real-time imaging, quickness of data collecting and ability to discriminate finest structural details. In this work, GPR has been used to investigate two different precast elements: precast reinforced concrete planks constituting the roof slab of a school and precast wood-cement blocks with insulation material pre-fitted used to build a perimeter wall of a private building. Visible cracks affected both constructions. For the assessment surveys, a GSSI 2.0 GHz GPR antenna has been used because of the high resolution required and the small size of the antenna case (155 by 90 by 105mm) enabling scanning up to 45mm from any obstruction. Finite Difference Time Domain (FDTD) numerical modelling was also performed to build a scenario of the expected GPR signal response for a preliminary real-time interpretation and to help solve uncertainties due to complex reflection patterns: simulated radargrams were built using Reflex Software v. 8.2, reproducing the same GPR pulse used for the surveys in terms of wavelet, nominal frequency, sample frequency and time window. Model geometries were derived from the design projects available both for the planks and the blocks; the electromagnetic properties of the materials (concrete, reinforcing bars, air-filled void, insulation and wooden concrete) were inferred from both values reported in literature and a preliminary interpretation of radargrams where internal layer interfaces were clearly recognizable and

Shielded loaded bowtie antenna incorporating the presence of paving structure for improved GPR pipe detection

Science.gov (United States)

Seyfried, Daniel; Jansen, Ronald; Schoebel, Joerg

2014-12-01

In civil engineering Ground Penetrating Radar becomes more and more a considerable tool for nondestructive testing and exploration of the underground. For example, the detection of existence of utilization pipe networks prior to construction works or detection of damaged spot beneath a paved street is a highly advantageous application. However, different surface conditions as well as ground bounce reflection and antenna cross-talk may seriously affect the detection capability of the entire radar system. Therefore, proper antenna design is an essential part in order to obtain radar data of high quality. In this paper we redesign a given loaded bowtie antenna in order to reduce strong and unwanted signal contributions such as ground bounce reflection and antenna cross-talk. During the optimization process we also review all parameters of our existing antenna in order to maximize energy transfer into ground. The entire process incorporating appropriate simulations along with running measurements on our GPR test site where we buried different types of pipes and cables for testing and developing radar hardware and software algorithms under quasi-real conditions is described in this paper.

Full-waveform inversion of GPR data acquired between boreholes in Rustrel carbonates

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Pinard Hugo

2016-01-01

Full Text Available Full waveform inversion (FWI of seismic or Ground Penetrating Radar data provides high-resolution quantitative images of the constitutive parameters of the rock/soil which control seismic/GPR wave propagation. We developed a 2D inversion tool in the frequency domain adapted to the multi-parameter physics controlling GPR propagation in isotropic non dispersive media, i.e. dielectric permittivity and electrical conductivity. This inversion engine was previously tested using synthetic 2D data to mitigate the trade-off between the two parameter classes. In this paper, we present the required processing techniques and first inversion results obtained on a real GPR dataset acquired in carbonates with a cross-hole configuration. The presence of the 2 m diameter underground gallery at depth constitutes a nice target to test the robustness, efficiency and resolution of the inversion in such high-contrasts context. Starting from a time tomographic image for the dielectric permittivity and from a homogeneous conductivity, we show that FWI is efficient to retrieve high resolution images of dielectric permittivity but struggles with electrical conductivity. As a quality control, we compare real and synthetic radargrams computed from the tomography and final images, showing the efficiency of the process to reconstruct some events but also underlying some issues, particularly on large incidence angles amplitude traces.

Analysis of the karst aquifer structure of the Lamalou area (Herault, France) with ground penetrating radar

International Nuclear Information System (INIS)

Al-Fares, W.; Bakalowicz, M.; Guerin, R.; Dukhan, M.

2004-01-01

The study site at Lamalou karst spring Hortus karst plateau) is situated 40 km north of Montpellier in France. It consists of a limestone plateau, drained by a karst conduit discharging as a spring. This conduit extends for a few dozen meters in fractured and karstified limestone rocks, 15 to 70 m below the surface. The conduit is accessible from the surface. The main goal of this study is to analyze the surface part of the karst and to highlight the karstic features and among them the conduit, and to test the performances of ground penetrating radar (GPR) in a karstic environment. This method thus appears particularly well adapted to the analysis of the near-surface (<30 m in depth) structure of a karst, especially when clayey coating or soil that absorbs and attenuates the radar is rare and discontinuous. A GPR pulse EKKO 100 (Sensors and Software) was used on the site with a 50 MHz antenna frequency. The results highlight structures characterizing the karstic environment: The epikarst, bedding planes, fractured and karstified zones, compact and massive rock and karrens, a typical karst landform. One of the sections revealed in detail the main conduit located at a depth of 20 m, and made it possible to determine its geometry. This site offers possibilities of validation of GPR data by giving direct access to the karstic conduit and through two cored boreholes. These direct observations confirm the interpretation of all the GPR sections. (author

Spatially Extensive Ground-Penetrating Radar Observations during NASA's 2017 SnowEx campaign

Science.gov (United States)

McGrath, D.; Webb, R.; Marshall, H. P.; Hale, K.; Molotch, N. P.

2017-12-01

Quantifying snow water equivalent (SWE) from space remains a significant challenge, particularly in regions of forest cover or complex topography that result in high spatial variability and present difficulties for existing remote sensing techniques. Here we use extensive ground-penetrating radar (GPR) surveys during the NASA SnowEx 2017 campaign to characterize snow depth, density, and SWE across the Grand Mesa field site with a wide range of varying canopy and topographical conditions. GPR surveys, which are sensitive to snow density and microstructure, provide independent information that can effectively constrain leading airborne and spaceborne SWE retrieval approaches. We find good agreement between GPR observations and a suite of supporting in situ measurements, including snowpits, probe lines, and terrestrial LiDAR. Preliminary results illustrate the role of vegetation in controlling SWE variability, with the greatest variability found in dense forests and lowest variability found in open meadows.

The soil classification and the subsurface carbon stock estimation with a ground-penetrating radar

International Nuclear Information System (INIS)

Onishi, K.; Rokugawa, S.; Kato, Y.

2002-01-01

One of the serious problems of the Kyoto Protocol is that we have no effective method to estimate the carbon stock of the subsurface. To solve this problem, we propose the application of ground-penetrating radar (GPR) to the subsurface soil survey. As a result, it is shown that GPR can detect the soil horizons, stones and roots. The fluctuations of the soil horizons in the forest are cleanly indicated as the reflection pattern of the microwaves. Considering the fact that the physical, chemical, and biological characteristics of each soil layer is almost unique, GPR results can be used to estimate the carbon stock in soil by combining with the vertical soil sample survey at one site. Then as a trial, we demonstrate to estimate the carbon content fixed in soil layers based on the soil samples and GPR survey data. we also compare this result with the carbon stock for the flat horizon case. The advantages of GPR usage for this object are not only the reduction of uncertainty and the cost, but also the environmental friendliness of survey manner. Finally, we summarize the adaptabilities of various antennas having different predominant frequencies for the shallow subsurface zone. (author)

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.

GPR scan assessment

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Abbas M. Abbas

2015-06-01

Full Text Available Mekaad Radwan monument is situated in the neighborhood of Bab Zuweila in the historical Cairo, Egypt. It was constructed at the middle XVII century (1635 AD. The building has a rectangle shape plan (13 × 6 m with the longitudinal sides approximately WNW-ESE. It comprises three storages namely; the ground floor; the opened floor (RADWAN Bench and the living floor with a total elevation of 15 m above the street level. The building suffers from severe deterioration phenomena with patterns of damage which have occurred over time. These deterioration and damages could be attributed to foundation problems, subsoil water and also to the earthquake that affected the entire Greater Cairo area in October 1992. Ground Penetrating Radar (GPR scan was accomplished against the walls of the opened floor (RADWAN Bench to evaluate the hazard impact on the walls textures and integrity. The results showed an anomalous feature through the southern wall of RADWAN Bench. A mathematical model has been simulated to confirm the obtained anomaly and the model response exhibited a good matching with the outlined anomaly.

Soil hydraulic material properties and layered architecture from time-lapse GPR

Science.gov (United States)

Jaumann, Stefan; Roth, Kurt

2018-04-01

Quantitative knowledge of the subsurface material distribution and its effective soil hydraulic material properties is essential to predict soil water movement. Ground-penetrating radar (GPR) is a noninvasive and nondestructive geophysical measurement method that is suitable to monitor hydraulic processes. Previous studies showed that the GPR signal from a fluctuating groundwater table is sensitive to the soil water characteristic and the hydraulic conductivity function. In this work, we show that the GPR signal originating from both the subsurface architecture and the fluctuating groundwater table is suitable to estimate the position of layers within the subsurface architecture together with the associated effective soil hydraulic material properties with inversion methods. To that end, we parameterize the subsurface architecture, solve the Richards equation, convert the resulting water content to relative permittivity with the complex refractive index model (CRIM), and solve Maxwell's equations numerically. In order to analyze the GPR signal, we implemented a new heuristic algorithm that detects relevant signals in the radargram (events) and extracts the corresponding signal travel time and amplitude. This algorithm is applied to simulated as well as measured radargrams and the detected events are associated automatically. Using events instead of the full wave regularizes the inversion focussing on the relevant measurement signal. For optimization, we use a global-local approach with preconditioning. Starting from an ensemble of initial parameter sets drawn with a Latin hypercube algorithm, we sequentially couple a simulated annealing algorithm with a Levenberg-Marquardt algorithm. The method is applied to synthetic as well as measured data from the ASSESS test site. We show that the method yields reasonable estimates for the position of the layers as well as for the soil hydraulic material properties by comparing the results to references derived from ground

Probing the Architecture of the Weathering Zone in a Tropical System in the Rio Icacos Watershed (Puerto Rico) With Drilling and Ground Penetrating Radar (GPR)

Science.gov (United States)

Orlando, J.; Comas, X.; Mount, G. J.; Brantley, S. L.

2012-12-01

Weathering processes in rapidly eroding systems such as humid tropical environments are complex and not well understood. The interface between weathered material (regolith) and non-weathered material (bedrock) is particularly important in these systems as it influences water infiltration and groundwater flow paths and movement. Furthermore, the spatial distribution of this interface is highly heterogeneous and difficult to image with conventional techniques such as direct coring and drilling. In this work we present results from a preliminary geophysical study in the Luquillo Critical Zone Observatory (LCZO) located in the rain forest in the Luquillo Mountains of northeastern Puerto Rico. The Luquillo Mountains are composed of volcaniclastic rocks which have been uplifted and metamorphosed by the Tertiary Rio Blanco quartz diorite intrusion. The Rio Blanco quartz diorite weathers spheroidally, creating corestones of relatively unweathered material that are surrounded by weathered rinds. A number of boreholes were drilled near the top of the Rio Icacos watershed, where the corestones are thought to be in the primary stages of formation, to constrain the regolith/bedrock interface and to provide an understanding of the depth to which corestones form. The depth of the water table was also a target goal in the project. Drilling reveals that corestones are forming in place, separated by fractures, even to depths of 10s of meters below ground surface. One borehole was drilled to a depth of about 25 meters and intersected up to 7 bedrock blocks (inferred to be incipient corestones) and the water table was measured at about 15 meters. Ground Penetrating Radar surveys were conducted in the same location to determine if GPR images variable thicknesses of saprolite overlying corestones. GPR common offset measurements and common midpoint surveys with 50, 100, and 200 MHz antenna frequencies were combined with borehole drillings in order to constrain geophysical results. We

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

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

Use of Ground Penetrating Radar at the FAA's National Airport Pavement Test Facility

Science.gov (United States)

Injun, Song

2015-04-01

The Federal Aviation Administration (FAA) in the United States has used a ground-coupled Ground Penetrating Radar (GPR) at the National Airport Pavement Test Facility (NAPTF) since 2005. One of the primary objectives of the testing at the facility is to provide full-scale pavement response and failure information for use in airplane landing gear design and configuration studies. During the traffic testing at the facility, a GSSI GPR system was used to develop new procedures for monitoring Hot Mix Asphalt (HMA) pavement density changes that is directly related to pavement failure. After reviewing current setups for data acquisition software and procedures for identifying different pavement layers, dielectric constant and pavement thickness were selected as dominant parameters controlling HMA properties provided by GPR. A new methodology showing HMA density changes in terms of dielectric constant variations, called dielectric sweep test, was developed and applied in full-scale pavement test. The dielectric constant changes were successfully monitored with increasing airplane traffic numbers. The changes were compared to pavement performance data (permanent deformation). The measured dielectric constants based on the known HMA thicknesses were also compared with computed dielectric constants using an equation from ASTM D4748-98 Standard Test Method for Determining the Thickness of Bound Pavement Layers Using Short-Pulse Radar. Six inches diameter cylindrical cores were taken after construction and traffic testing for the HMA layer bulk specific gravity. The measured bulk specific gravity was also compared to monitor HMA density changes caused by aircraft traffic conditions. Additionally this presentation will review the applications of the FAA's ground-coupled GPR on embedded rebar identification in concrete pavement, sewer pipes in soil, and gage identifications in 3D plots.

An Integration of Ground-Penetrating Radar, Remote Sensing, and Discharge Records of the Modern Kicking Horse River, BC

Science.gov (United States)

Cyples, N.; Ielpi, A.; Dirszowsky, R.

2017-12-01

The Kicking Horse River is a gravel-bed stream originating from glacial meltwater supplied by the Wapta Icefields in south-eastern British Columbia. An alluvial tract extends for 7 km through Field, BC, where the trunk channel undergoes diurnal and seasonal fluctuations in flow as a result of varying glacial-meltwater supply and runoff recharge. Prior studies erected the Kicking Horse River as a reference for proximal braided systems, and documented bar formation and sediment distribution patterns from ground observations. However, a consistent model of planform evolution and related stratigraphic signature is lacking. Specific objectives of this study are to examine the morphodynamic evolution and stratigraphic signature of channel-bar complexes using high-resolution satellite imagery, sedimentologic and discharge observations, and ground-penetrating radar (GPR). Remote sensing highlights rates of lateral channel migration of as much as 270 meters over eight years ( 34 meters/year), and demonstrates how flood stages are associated with stepwise episodes of channel braiding and anabranching. GPR analysis aided in the identification of five distinct radar facies, including: discontinuous, inclined, planar, trough-shaped, and mounded reflectors, which were respectively related to specific architectural elements and fluvial processes responsible for bar evolution. Across-stream GPR transects demonstrated higher heterogeneity in facies distribution, while downstream-oriented transects yielded a more monotonous distribution in radar facies. Notably, large-scale inclined reflectors related to step-wise bar accretion are depicted only in downstream-oriented transects, while discontinuous reflectors related to bedform stacking appear to be dominant in along-stream transects. Integration of sedimentological data with remote sensing, gauging records, and GPR analysis allows for high-resolution modelling of stepwise changes in alluvial morphology. Conceptual models stemming

GPR image analysis to locate water leaks from buried pipes by applying variance filters

Science.gov (United States)

Ocaña-Levario, Silvia J.; Carreño-Alvarado, Elizabeth P.; Ayala-Cabrera, David; Izquierdo, Joaquín

2018-05-01

Nowadays, there is growing interest in controlling and reducing the amount of water lost through leakage in water supply systems (WSSs). Leakage is, in fact, one of the biggest problems faced by the managers of these utilities. This work addresses the problem of leakage in WSSs by using GPR (Ground Penetrating Radar) as a non-destructive method. The main objective is to identify and extract features from GPR images such as leaks and components in a controlled laboratory condition by a methodology based on second order statistical parameters and, using the obtained features, to create 3D models that allows quick visualization of components and leaks in WSSs from GPR image analysis and subsequent interpretation. This methodology has been used before in other fields and provided promising results. The results obtained with the proposed methodology are presented, analyzed, interpreted and compared with the results obtained by using a well-established multi-agent based methodology. These results show that the variance filter is capable of highlighting the characteristics of components and anomalies, in an intuitive manner, which can be identified by non-highly qualified personnel, using the 3D models we develop. This research intends to pave the way towards future intelligent detection systems that enable the automatic detection of leaks in WSSs.

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

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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.

Seasonal variations measured by TDR and GPR on an anthropogenic sandy soil and the implications for utility detection

Science.gov (United States)

Curioni, Giulio; Chapman, David N.; Metje, Nicole

2017-06-01

The electromagnetic (EM) soil properties are dynamic variables that can change considerably over time, and they fundamentally affect the performance of Ground Penetrating Radar (GPR). However, long-term field studies are remarkably rare and records of the EM soil properties and their seasonal variation are largely absent from the literature. This research explores the extent of the seasonal variation of the apparent permittivity (Ka) and bulk electrical conductivity (BEC) measured by Time Domain Reflectometry (TDR) and their impact on GPR results, with a particularly important application to utility detection. A bespoke TDR field monitoring station was specifically developed and installed in an anthropogenic sandy soil in the UK for 22 months. The relationship between the temporal variation of the EM soil properties and GPR performance has been qualitatively assessed, highlighting notably degradation of the GPR images during wet periods and a few days after significant rainfall events following dry periods. Significantly, it was shown that by assuming arbitrary average values (i.e. not extreme values) of Ka and BEC which do not often reflect the typical conditions of the soil, it can lead to significant inaccuracies in the estimation of the depth of buried targets, with errors potentially up to approximately 30% even over a depth of 0.50 m (where GPR is expected to be most accurate). It is therefore recommended to measure or assess the soil conditions during GPR surveys, and if this is not possible to use typical wet and dry Ka values reported in the literature for the soil expected at the site, to improve confidence in estimations of target depths.

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

AVALIAÇÃO DO GPR NA ESTIMATIVA DA BATIMETRIA DE UMA CAIXA DE DECANTAÇÃO EMPREGANDO O APLICATIVO GRATUITO “GPR BATHYMETRY” NA ANÁLISE DOS RADARGRAMAS

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Sandro Henrique de Faria

Full Text Available Este trabalho tem como objetivos avaliar o desempenho do GPR (Ground Penetrating RADAR para aplicações batimétricas em ambiente controlado e do aplicativo “GPR Bathymetry”, desenvolvido para análise de radargramas batimétricos. O estudo foi realizado em uma caixa de decantação da estação de tratamento de água da qual se tem o “as-built”, obtido com estação total, que será empregado nos testes de validação. Realizaram-se três testes de comparação: comparações pontuais; entre Modelos Digitais de Elevação (MDE gerados a partir do interpolador Topo to Raster; e entre os volumes calculados a partir dos MDE’s. Na comparação pontual a maior amplitude de discrepância entre as médias foi de 8cm. Para a amostra de discrepâncias entre os MDE’s, a amplitude foi de 9cm, média de 2cm, acurácia estimada de 4cm e o RMS de 3cm. Na comparação volumétrica obteve-se o valor de 800,6m³ com dados de referência e 806,4m³ com dados do GPR, resultando numa diferença de 1% entre os modelos. Conclui-se que para um reservatório construído em concreto armado, profundidades variando de 3 a 3,5 metros, o levantamento do relevo submerso empregando um GPR apresentou resultados promissores e um MDE com acurácia estimada de 4cm e discrepâncias de até 9cm

Subsurface Investigation using 2D Resistivity and Ground Penetrating Radar at Teluk Kumbar, Penang

Science.gov (United States)

Teoh, YJ; Bruka, MA; Idris, NM; Ismail, NA; Muztaza, NM

2018-04-01

The objective of this study is to determine the structure and condition of the subsurface by using 2D resistivity and Ground Penetrating Radar (GPR) methods. The study was conducted at SK Sungai Batu, Teluk Kumbar, Penang Island. For 2D resistivity method, Wenner-Schlumberger array was used while for GPR, 250 MHz antenna was used at the site. The survey consists of 200m length survey line. GPR result shows that there is high intensity of EM. 2D resistivity result shows that the low resistivity region (200 Ωm to 340 Ωm) appears to be at the centre of the survey line from depth 7 m to 13 m. Meanwhile, the higher resistivity region (4000 Ωm to 6000 Ωm) may indicate the bedrock structure of the subsurface, which is the granitic rock. This region is bedrock which rested at depth 14 m and below. In conclusion, data obtained from GPR and 2D resistivity methods can be easily correlated to determine the features of the subsurface.

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

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

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.

GPR120

DEFF Research Database (Denmark)

Gao, B.; Huang, Q.; Jie, Q.

2015-01-01

/2 cascade, while low concentrations elevated P38 and increased adipogenesis. The fine molecular regulation of GPR120 was implemented by up-regulating different integrin subunits (alpha 1, alpha 2 and beta 1; alpha 5 and beta 3). The administration of high doses of TUG-891 rescued oestrogen-deficient bone...... was involved in the cytoplasmic regulation of a seesaw-like balance between ERK and p38 phosphorylation. These findings provide new hope for developing novel remedies to treat osteoporosis by adjusting the GPR120-mediated differentiation balance of BMMSCs....

GPR119 as a fat sensor

DEFF Research Database (Denmark)

Hansen, Harald S; Rosenkilde, Mette M; Holst, Jens Juul

2012-01-01

acting through, for example, GPR40, but is also probably mediated in large part through the luminal formation of 2-monoacylglycerol acting on the 'fat sensor' GPR119. In the pancreas GPR119 may also be stimulated by 2-monoacylglycerol generated from local turnover of pancreatic triacylglycerol. Knowledge...

Applications of GPR in archaeological prospecting and cultural heritage diagnostics: Research Perspectives in COST Action TU1208

Science.gov (United States)

Pajewski, Lara; Benedetto, Andrea; Schettini, Giuseppe; Soldovieri, Francesco

2013-04-01

Ground Penetrating Radar (GPR) is a safe, non-destructive and non-invasive imaging technique that can be effectively used for advanced inspection of composite structures and for diagnostics affecting the whole life-cycle of civil engineering works. GPR can also be successfully employed in archaeological prospecting and cultural heritage diagnostics. In many Countries, where the archeological patrimony is an outstanding value (as Egypt, Israel, Greece, Central and South America), GPR is usually employed both as a diagnostic tool for the preventive detection of archeological structures and as the most advanced instrument able to prospect geometry and shape of underground valuable sites. However many uncertainties persist, because of several difficulties and ambiguities due to the complexity of the image processing in heterogeneous environment. It is possible to identify three main areas, in GPR field, that have to be addressed in order to promote the use of this technology in archaeological prospecting and cultural heritage diagnostics. These are: a) increase of the system sensitivity to enable the usability in a wider range of conditions, archeological sites are often located in impervious and critical environments; 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. It is also important to further investigate and promote a combined use of GPR with other non-invasive advanced techniques, typically used in the archeological investigation. In this framework, the COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar", proposed by a research team of "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

GPR Activities in Italy: a Review

Science.gov (United States)

Tosti, Fabio; Ambrosanio, Michele; Battaglia, Enzo; Bianchini Ciampoli, Luca; De Carlo, Lorenzo; Matera, Loredana; Prontera, Santo; Sileo, Maria

2015-04-01

the ASTM D 4748-98 and the ASTM D 6432-99 dealing with, respectively, thicknesses evaluation of bound layers in road pavements, and equipment, field procedures and data-interpretation for the electromagnetic evaluation of subsurface materials, it has to be noted that the Italian body of laws and rules tackles the ground-penetrating radar applications under an indirect and partial approach. Despite of such situation, national guidelines concerning utilities-detection activities as well as other theoretical and practical guidelines established by the major Italian private enterprises on this field can be also considered highly relevant. Moreover, a further focus on the activities and main devices of the major Italian ground-penetrating radar manufacturers have been thoroughly described. Under a research and innovation perspective, the most important test sites, such as the site of the University of Salento to reconstruct archaeological and urban subsurface scenarios have been listed along with the main advances reached in integrating ground-penetrating radar with other non-destructive techniques, to inform and potentially improve the possibility of new developments and collaborations. Acknowledgements - This work is a contribution from the Training School on "Civil Engineering Applications of GPR" held in Pisa, Italy, on September 22nd - 25th, 2014, within the framework of the COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar".

Alteraciones del suelo: Descubrimiento de cuerpos enterrados y otras evidencias usando el radar de subsuelo/Alterations in ground: Discovery of buried bodies and other evidence using subsurface radar

Directory of Open Access Journals (Sweden)

Mercè Subirana Domènech (España

2009-01-01

Full Text Available El radar de subsuelo (GPR es un eficiente y efectivo medio de búsqueda de evidencias enterradas, sean éstas una tumba clandestina, un enterramiento formal, u objetos desaparecidos de la escena del crimen. Los procedimientos del GPR usados por el laboratorio central de identificación del ejército de los Estados Unidos, Hawaii (CILHI, son el resultado de varios años de experimentación en diversos tipos de suelo en Hawaii, sudeste asiático y los Estados Unidos continentales. Normalmente, este método de detección remota no proporciona información directa sobre si hay un cuerpo u otro objeto específico debajo del suelo. La mayor parte del tiempo el GPR ha sido usado para determinar donde no se encuentra un objeto. La principal característica del GPR es que puede detectar cambios recientes en terrenos poco profundos provocados por alteraciones del suelo y la intrusión de un material diferente. Mediante los métodos descritos aquí, el investigador debería ser capaz de determinar las coordenadas exactas de una perturbación del terreno, así como el tamaño aproximado, la forma general, y la profundidad del material enterrado. El éxito dependerá de las condiciones del suelo. Las condiciones aptas o no prácticas para el uso del GPR se hallan en la literatura específica. Esta tecnología de detección remota puede tener un mayor campo de aplicación en investigaciones criminales debido a la reciente introducción de un software de uso más sencillo y de un hardware más portátil. Radar (GPR subsoil is an efficient and effective mean of searching for buried evidence, whether a clandestine grave, a formal burial, or missing items from the crime scene. The GPR procedures used by the central laboratory identification of the army of the United States, Hawaii (CILHI, are the result of several years of experimentation in different types of soil in Hawaii, Southeast Asia and the United States mainland. Normally, this method of remote sensing

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.

Efficiency evaluation of ground-penetrating radar by the results of measurement of dielectric properties of soils

Energy Technology Data Exchange (ETDEWEB)

Khakiev, Zelimkhan; Kislitsa, Konstantin; Yavna, Victor [Rostov State Transport University, Rostov-on-Don (Russian Federation)

2012-12-15

The work considers the depth evaluation of ground penetrating radar (GPR) surveys using the attenuation factor of electromagnetic radiation in a medium. A method of determining the attenuation factor of low-conductive non-magnetic soils is developed based on the results of direct measurements of permittivity and conductivity of soils in the range of typical frequencies of GPR. The method relies on measuring the shift and width of the resonance line after a soil sample is being placed into a tunable cavity resonator. The advantage of this method is the preservation of soil structure during the measurement.

Reconstructing the Roman Site “Aquis Querquennis” (Bande, Spain from GPR, T-LiDAR and IRT Data Fusion

Directory of Open Access Journals (Sweden)

Iván Puente

2018-03-01

Full Text Available This work presents the three-dimensional (3D reconstruction of one of the most important archaeological sites in Galicia: “Aquis Querquennis” (Bande, Spain using in-situ non-invasive ground-penetrating radar (GPR and Terrestrial Light Detection and Ranging (T-LiDAR techniques, complemented with infrared thermography. T-LiDAR is used for the recording of the 3D surface of this particular case and provides high resolution 3D digital models. GPR data processing is performed through the novel software tool “toGPRi”, developed by the authors, which allows the creation of a 3D model of the sub-surface and the subsequent XY images or time-slices at different depths. All these products are georeferenced, in such a way that the GPR orthoimages can be combined with the orthoimages from the T-LiDAR for a complete interpretation of the site. In this way, the GPR technique allows for the detection of the structures of the barracks that are buried, and their distribution is completed with the structure measured by the T-LiDAR on the surface. In addition, the detection of buried elements made possible the identification and labelling of the structures of the surface and their uses. These structures are additionally inspected with infrared thermography (IRT to determine their conservation condition and distinguish between original and subsequent constructions.

Detecting and characterizing unroofed caves by ground penetrating radar

Science.gov (United States)

Čeru, Teja; Šegina, Ela; Knez, Martin; Benac, Čedomir; Gosar, Andrej

2018-02-01

The bare karst surface in the southeastern part of Krk Island (Croatia) is characterized by different surface karst features, such as valley-like shallow linear depressions and partially or fully sediment-filled depressions of various shapes and sizes. They were noticed due to locally increased thickness of sediment and enhanced vegetation but had not yet been systematically studied and defined. Considering only the geometry of the investigated surface features and the rare traces of cave environments detected by field surveys, it was unclear which processes (surface karstification and/or speleogenesis) contributed most to their formation. The low-frequency ground penetrating radar (GPR) method using a special 50 MHz RTA antenna was applied to study and describe these karst features. Three study sites were chosen and 5 km of GPR profiles were positioned to include various surface features. The results obtained from the GPR investigation lead to the following conclusions: (1) an increased thickness of sediment was detected in all the investigated depressions indicating their considerable depth; (2) areas between different depressions expressed as attenuated zones in GPR images reveal their interconnection; (3) transitions between surface and underground features are characterized by a collapsed passage visible in the GPR data; and (4) an underground continuation of surface valley-like depressions was detected, proving the speleogenetic origin of such features. Subsurface information obtained using GPR indicates that the valley-like depressions, irregular depressions completely or partially filled with sediment, and some dolines are associated with a nearly 4 km-long unroofed cave and developed as a result of karst denudation. In the regional context, these results suggest long-lasting karstification processes in the area, in contrast to the pre-karstic fluvial phase previously assumed to have occurred here. This research is the first application of the GPR method to

GPR signal enhancement using band-pass and K–L filtering: a case study for the evaluation of grout in a shielded tunnel

International Nuclear Information System (INIS)

Xie, Xiongyao; Zeng, Chenchao; Wang, Zhigao

2013-01-01

The rapidness, non-destructiveness and high precision of ground penetrating radar (GPR) technology has enabled it to be widely and increasingly used in tunnel detection. However, data acquisition was usually restricted by physical and many other limitations. In order to improve the signal-to-noise ratio, band-pass and Karhunen–Loève (K–L) filtering are recommended. An evaluation of Yingbin No. 3 Road Tunnel is presented to illustrate the effectiveness of GPR in the inspection of the thickness of the grouting layer behind the segment and the function of the two methods mentioned above. The advantages and limitations of these two processing methods are discussed in this paper and suggestions are provided. (paper)

Inspection of a large concrete block containing embedded defects using ground penetrating radar

Science.gov (United States)

Eisenmann, David; Margetan, Frank J.; Koester, Lucas; Clayton, Dwight

2016-02-01

Ground penetrating radar (GPR), also known as impulse response radar, was used to examine a thick concrete block containing reinforcing steel bars (rebar) and embedded defects. The block was located at the University of Minnesota, measured approximately 7 feet tall by 7 feet wide by 40 inches deep, and was intended to simulate certain aspects of a concrete containment wall at a nuclear power plant. This paper describes the measurements that were made and various analyses of the data. We begin with a description of the block itself and the GPR equipment and methods used in our inspections. The methods include the application of synthetic aperture focusing techniques (SAFT). We then present and discuss GPR images of the block's interior made using 1600-MHz, 900-MHz, and 400-MHz antennas operating in pulse/echo mode. A number of the embedded defects can be seen, and we discuss how their relative detectability can be quantified by comparison to the response from nearby rebar. We next discuss through-transmission measurements made using pairs of 1600-MHz and 900-MHz antennas, and the analysis of that data to deduce the average electromagnetic (EM) wave speed and attenuation of the concrete. Through the 40-inch thickness, attenuation rises approximately linearly with frequency at a rate near 0.7 dB/inch/GHz. However, there is evidence that EM properties vary with depth in the block. We conclude with a brief summary and a discussion of possible future work.

GPR119 - a major Enteroendocrine Sensor of Dietary Triglyceride Metabolites Co-acting in Synergy with FFA1 (GPR40)

DEFF Research Database (Denmark)

Ekberg, Jeppe H; Pedersen, Maria Hauge; Kristensen, Line V

2016-01-01

the FFA1 agonist was administered on top of appropriately low doses of the GPR119 agonist a clear synergistic, i.e. more than additive effect was observed. It is concluded that the 2-MAG receptor GPR119 is at least as important as the LCFA receptor FFA1 in mediating the triglyceride-induced secretion......Triglycerides are among the most efficacious stimulators of incretin secretion; however the relative importance of FFA1 (GPR40), FFA4 (GPR120) and GPR119 which all recognize triglyceride metabolites, i.e. LCFA and 2-MAG respectively, is still unclear. Here, we find all three receptors to be highly...... the synthetic FFA1 agonists, TAK-875 stimulated GLP-1 secretion to a similar extent as the prototype GLP-1 secretagogue neuromedin C, this however only corresponded to approx. half the maximal efficiency of the GPR119 agonist AR231453 whereas the GPR120 agonist Metabolix-209 had no effect. Importantly, when...

GPR119 agonists: a promising approach for T2DM treatment? A SWOT analysis of GPR119.

Science.gov (United States)

Kang, Sang-Uk

2013-12-01

Ever since its advent as a promising therapeutic target for type 2 diabetes mellitus (T2DM), G-protein-coupled receptor 119 (GPR119) has received much interest from the pharmaceutical industry. This interest peaked in June 2010, when Sanofi-Aventis agreed to pay Metabolex (Cymabay Therapeutics) US$375 million for MBX-2982, which was a representative orally active GPR119 agonist. However, Sanofi-Aventis opted to terminate the deal in May 2011 and another leading GPR119 agonist, GSK1292263, had a loss of efficacy during its clinical trial. In this review, I discuss the pros and cons of GPR119 through a strengths, weaknesses, opportunities, and threats (SWOT) analysis and propose development strategies for the eventual success of a GPR119 agonist development program. Copyright © 2013 Elsevier Ltd. All rights reserved.

GPR survey, as one of the best geophysical methods for social and industrial needs

Science.gov (United States)

Chernov, Anatolii

2016-04-01

This paper is about ways and methods of applying non-invasive geophysical method - Ground penetrating radar (GPR) survey in different spheres of science, industry, social life and culture. Author would like to show that geological methods could be widely used for solving great variety of industrial, human safety and other problems. In that article, we take GPR survey as an example of such useful geophysical methods. It is a fact that investigation of near surface underground medium is important process, which influence on development of different spheres of science and social life: investigation of near surface geology (layering, spreading of rock types, identification of voids, etc.), hydrogeology (depth to water horizons, their thickness), preparation step for construction of roads and buildings (civil geology, engineering geology), investigation of cultural heritage (burial places, building remains,...), ecological investigations (land slides, variation in underground water level, etc.), glaciology. These tasks can be solved by geological methods, but as usual, geophysical survey takes a lot of time and energy (especially electric current and resistivity methods, seismic survey). Author claims that GPR survey can be performed faster than other geophysical surveys and results of GPR survey are informative enough to make proper conclusions. Some problems even cannot be solved without GPR. For example, identification of burial place (one of author's research objects): results of magnetic and electric resistivity tomography survey do not contain enough information to identify burial place, but according to anomalies on GPR survey radarograms, presence of burial place can be proven. Identification of voids and non-magnetic objects also hardly can be done by another non-invasive geophysics surveys and GPR is applicable for that purpose. GPR can be applied for monitoring of dangerous processes in geological medium under roads, buildings, parks and other places of human

Inversion and sensitivity analysis of ground penetrating radar data with waveguide dispersion using deterministic and Markov chain Monte Carlo methods

NARCIS (Netherlands)

Bikowski, J.; Huisman, J.A.; Vrugt, J.A.; Vereecken, H.; van der Kruk, J.

2012-01-01

Ground-penetrating radar (GPR) data affected by waveguide dispersion are not straightforward to analyse. Therefore, waveguide dispersed common midpoint measurements are typically interpreted using so-called dispersion curves, which describe the phase velocity as a function of frequency. These

Non-invasive monitoring of below ground cassava storage root bulking by ground penetrating radar technology

Science.gov (United States)

Ruiz Vera, U. M.; Larson, T. H.; Mwakanyamale, K. E.; Grennan, A. K.; Souza, A. P.; Ort, D. R.; Balikian, R. J.

2017-12-01

Agriculture needs a new technological revolution to be able to meet the food demands, to overcome weather and natural hazards events, and to monitor better crop productivity. Advanced technologies used in other fields have recently been applied in agriculture. Thus, imagine instrumentation has been applied to phenotype above-ground biomass and predict yield. However, the capability to monitor belowground biomass is still limited. There are some existing technologies available, for example the ground penetrating radar (GPR) which has been used widely in the area of geology and civil engineering to detect different kind of formations under the ground without the disruption of the soil. GPR technology has been used also to monitor tree roots but as yet not crop roots. Some limitation are that the GPR cannot discern roots smaller than 2 cm in diameter, but it make it feasible for application in tuber crops like Cassava since harvest diameter is greater than 4 cm. The objective of this research is to test the availability to use GPR technology to monitor the growth of cassava roots by testing this technique in the greenhouse and in the field. So far, results from the greenhouse suggest that GPR can detect mature roots of cassava and this data could be used to predict biomass.

Geological signatures of drillhole radar reflectors in ONKALO

International Nuclear Information System (INIS)

Doese, C.; Gustafsson, J.

2011-12-01

The geological signatures of radar reflectors in ONKALO have been evaluated as a subactivity within the Joint Work Programme 'Rock Suitability Criteria' strategies and methodology' between Svensk Kaernbraenslehantering AB and Posiva Oy. In addition to the geological signature, the usage of geophysical data to predict large fractures was evaluated. Pilot hole radar loggings were carried out using a RAMAC GPR-250 MHz dipole antenna. The radar data were evaluated and reflectors with known position and intersection angle to the pilot hole were correlated with fractures or foliation in the pilot hole and with Tunnel Crosscutting Fractures in the tunnel. This data served as in-data for the evaluation of the geological signatures of radar reflectors. The result of the evaluation is not univocal. Half of the reflectors could be explained by fractures in the pilot hole, but only about 10 % of the reflectors can be explained by Tunnel Crosscutting Fractures. Of these 10 %, 2/3 can also be explained by foliation, leaving only some 3 % of the total reflectors more unambiguously correlated with Tunnel Crosscutting Fractures. The fractures correlated with radar reflectors do not diverge much from other fractures. Fractures having intersection angles of 30 deg- 60 deg are more likely to be detected by radar relative to other. Other properties that seem to be overrepresented in fractures correlated with radar reflectors are quartz and/or graphite content, width ≥0.8 mm and higher alteration (J a ≥3), but the data is not unambiguous. (orig.)

Suitability of ground penetrating radar for locating large fractures

Energy Technology Data Exchange (ETDEWEB)

Heikkinen, E. [Poeyry Finland Oy, Vantaa (Finland); Kantia, P. [Roadscanners Oy, Rovaniemi (Finland)

2011-12-15

Posiva Oy is responsible for preparation of final disposal of spent nuclear fuel in Olkiluoto. The knowledge about existing network of fractures is important for the safety and feasibility of the final repository. The bedrock properties essential for safety case are analysed in investigations of Rock Suitability Criteria (RSC). One subtask in RSC is avoidance of large (long) fractures adjacent to disposal holes. The long fractures have been defined in tunnel mapping to indicate tunnel cross-cutting features (TCF) or full perimeter intersections (FPI). Suitability of ground penetrating radar (GPR) method for locating large fractures was assessed. The assessment used data measured with 100 MHz and 270 MHz radar tool on ONKALO access tunnel right-hand wall, chainage 3344 - 3578 and on TKU-3 niche floor chainage 15 - 55 and 25 - 67 m. GPR images were processed to enhance reflections and suppress interference and diffractions. Images were placed on measurement position in 3D presentation software. The tunnel wall and floor mapping data was presented along with GPR images. A review of observed GPR reflections, and assessment of visibility of large fractures, was drawn on basis of 3D view examination. The GPR tool can detect reflections from cleaned and dry rock floor and wall. Depth of penetration is 8-12 m for 270 MHz antenna. The antenna has high resolution. Coupling on rock surface is good, which suppresses ringing and interference. Penetration is 20-24 m for 100 MHz antenna, which has a trade off of higher interference due to weaker contact to surface caused by large antenna. There are observed many kind of reflecting surfaces and diffractors in the images, like for example lithological contacts and high grade shearing, and also fractures. Proper manner to apply the method is to use raw and processed images during geological mapping to confirm the origin of reflections. Reflections deemed to be caused by fractures are useful to be compiled to 3D model objects. The

Suitability of ground penetrating radar for locating large fractures

International Nuclear Information System (INIS)

Heikkinen, E.; Kantia, P.

2011-12-01

Posiva Oy is responsible for preparation of final disposal of spent nuclear fuel in Olkiluoto. The knowledge about existing network of fractures is important for the safety and feasibility of the final repository. The bedrock properties essential for safety case are analysed in investigations of Rock Suitability Criteria (RSC). One subtask in RSC is avoidance of large (long) fractures adjacent to disposal holes. The long fractures have been defined in tunnel mapping to indicate tunnel cross-cutting features (TCF) or full perimeter intersections (FPI). Suitability of ground penetrating radar (GPR) method for locating large fractures was assessed. The assessment used data measured with 100 MHz and 270 MHz radar tool on ONKALO access tunnel right-hand wall, chainage 3344 - 3578 and on TKU-3 niche floor chainage 15 - 55 and 25 - 67 m. GPR images were processed to enhance reflections and suppress interference and diffractions. Images were placed on measurement position in 3D presentation software. The tunnel wall and floor mapping data was presented along with GPR images. A review of observed GPR reflections, and assessment of visibility of large fractures, was drawn on basis of 3D view examination. The GPR tool can detect reflections from cleaned and dry rock floor and wall. Depth of penetration is 8-12 m for 270 MHz antenna. The antenna has high resolution. Coupling on rock surface is good, which suppresses ringing and interference. Penetration is 20-24 m for 100 MHz antenna, which has a trade off of higher interference due to weaker contact to surface caused by large antenna. There are observed many kind of reflecting surfaces and diffractors in the images, like for example lithological contacts and high grade shearing, and also fractures. Proper manner to apply the method is to use raw and processed images during geological mapping to confirm the origin of reflections. Reflections deemed to be caused by fractures are useful to be compiled to 3D model objects. The

Sea Ice Thickness Measurement by Ground Penetrating Radar for Ground Truth of Microwave Remote Sensing Data

Science.gov (United States)

Matsumoto, M.; Yoshimura, M.; Naoki, K.; Cho, K.; Wakabayashi, H.

2018-04-01

Observation of sea ice thickness is one of key issues to understand regional effect of global warming. One of approaches to monitor sea ice in large area is microwave remote sensing data analysis. However, ground truth must be necessary to discuss the effectivity of this kind of approach. The conventional method to acquire ground truth of ice thickness is drilling ice layer and directly measuring the thickness by a ruler. However, this method is destructive, time-consuming and limited spatial resolution. Although there are several methods to acquire ice thickness in non-destructive way, ground penetrating radar (GPR) can be effective solution because it can discriminate snow-ice and ice-sea water interface. In this paper, we carried out GPR measurement in Lake Saroma for relatively large area (200 m by 300 m, approximately) aiming to obtain grand truth for remote sensing data. GPR survey was conducted at 5 locations in the area. The direct measurement was also conducted simultaneously in order to calibrate GPR data for thickness estimation and to validate the result. Although GPR Bscan image obtained from 600MHz contains the reflection which may come from a structure under snow, the origin of the reflection is not obvious. Therefore, further analysis and interpretation of the GPR image, such as numerical simulation, additional signal processing and use of 200 MHz antenna, are required to move on thickness estimation.

Parameterizing road construction in route-based road weather models: can ground-penetrating radar provide any answers?

International Nuclear Information System (INIS)

Hammond, D S; Chapman, L; Thornes, J E

2011-01-01

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. (technical design note)

Interpretation of Ground Penetrating Radar data at the Hanford Site, Richland, Washington

International Nuclear Information System (INIS)

Bergstrom, K.A.; Mitchell, T.H.; Kunk, J.R.

1993-07-01

Ground Penetrating Radar (GPR) is being used extensively during characterization and remediation of chemical and radioactive waste sites at the Hanford Site in Washington State. Time and money for GPR investigations are often not included during the planning and budgeting phase. Therefore GPR investigations must be inexpensive and quick to minimize impact on already established budgets and schedules. An approach to survey design, data collection, and interpretation has been developed which emphasizes speed and budget with minimal impact on the integrity of the interpretation or quality of the data. The following simple rules of thumb can be applied: (1) Assemble as much pre-survey information as possible, (2) Clearly define survey objectives prior to designing the survey and determine which combination of geophysical methods will best meet the objectives, (3) Continuously communicate with the client, before, during and after the investigation, (4) Only experienced GPR interpreters should acquire the field data, (5) Use real-time monitoring of the data to determine where and how much data to collect and assist in the interpretation, (6) Always ''error'' in favor of collecting too much data, (7) Surveys should have closely spaced (preferably 5 feet, no more than 10 feet), orthogonal profiles, (8) When possible, pull the antenna by hand

Interpretation of Ground Penetrating Radar data at the Hanford Site, Richland, Washington

Energy Technology Data Exchange (ETDEWEB)

Bergstrom, K.A.; Mitchell, T.H.; Kunk, J.R.

1993-07-01

Ground Penetrating Radar (GPR) is being used extensively during characterization and remediation of chemical and radioactive waste sites at the Hanford Site in Washington State. Time and money for GPR investigations are often not included during the planning and budgeting phase. Therefore GPR investigations must be inexpensive and quick to minimize impact on already established budgets and schedules. An approach to survey design, data collection, and interpretation has been developed which emphasizes speed and budget with minimal impact on the integrity of the interpretation or quality of the data. The following simple rules of thumb can be applied: (1) Assemble as much pre-survey information as possible, (2) Clearly define survey objectives prior to designing the survey and determine which combination of geophysical methods will best meet the objectives, (3) Continuously communicate with the client, before, during and after the investigation, (4) Only experienced GPR interpreters should acquire the field data, (5) Use real-time monitoring of the data to determine where and how much data to collect and assist in the interpretation, (6) Always ``error`` in favor of collecting too much data, (7) Surveys should have closely spaced (preferably 5 feet, no more than 10 feet), orthogonal profiles, (8) When possible, pull the antenna by hand.

Surveying glacier bedrock topography with a helicopter-borne dual-polarization ground-penetrating radar system

Science.gov (United States)

Langhammer, L.; Rabenstein, L.; Schmid, L.; Bauder, A.; Schaer, P.; Maurer, H.

2017-12-01

Glacier mass estimations are crucial for future run-off projections in the Swiss Alps. Traditionally, ice thickness modeling approaches and ground-based radar transects have been the tools of choice for estimating glacier volume in high mountain areas, but these methods either contain high uncertainties or are logistically expensive and offer mostly only sparse subsurface information. We have developed a helicopter-borne dual-polarization ground-penetrating radar (GPR) system, which enhances operational feasibility in rough, high-elevation terrain and increases the data output per acquisition campaign significantly. Our system employs a prototype pulseEKKO device with two broadside 25-MHz antenna pairs fixed to a helicopter-towed wooden frame. Additionally attached to the system are a laser altimeter for measuring the flight height above ground, three GPS receivers for accurate positioning and a GoPro camera for obtaining visual images of the surface. Previous investigations have shown the significant impact of the antenna dipole orientation on the detectability of the bedrock reflection. For optimal results, the dipoles of the GPR should be aligned parallel to the strike direction of the surrounding mountain walls. In areas with a generally unknown bedrock topography, such as saddle areas or diverging zones, a dual-polarization system is particularly useful. This could be demonstrated with helicopter-borne GPR profiles acquired on more than 25 glaciers in the Swiss Alps. We observed significant differences in ice-bedrock interface visibility depending on the orientation of the antennas.

Two-Dimensional Linear Inversion of GPR Data with a Shifting Zoom along the Observation Line

Directory of Open Access Journals (Sweden)

Raffaele Persico

2017-09-01

Full Text Available Linear inverse scattering problems can be solved by regularized inversion of a matrix, whose calculation and inversion may require significant computing resources, in particular, a significant amount of RAM memory. This effort is dependent on the extent of the investigation domain, which drives a large amount of data to be gathered and a large number of unknowns to be looked for, when this domain becomes electrically large. This leads, in turn, to the problem of inversion of excessively large matrices. Here, we consider the problem of a ground-penetrating radar (GPR survey in two-dimensional (2D geometry, with antennas at an electrically short distance from the soil. In particular, we present a strategy to afford inversion of large investigation domains, based on a shifting zoom procedure. The proposed strategy was successfully validated using experimental radar data.

Resolution of lava tubes with ground penetrating radar: preliminary results from the TubeX project

Science.gov (United States)

Esmaeili, S.; Kruse, S.; Garry, W. B.; Whelley, P.; Young, K.; Jazayeri, S.; Bell, E.; Paylor, R.

2017-12-01

As early as the mid 1970's it was postulated that planetary tubes or caves on other planetary bodies (i.e., the Moon or Mars) could provide safe havens for human crews, protect life and shield equipment from harmful radiation, rapidly fluctuating surface temperatures, and even meteorite impacts. What is not clear, however, are the exploration methods necessary to evaluate a potential tube-rich environment to locate suitable tubes suitable for human habitation. We seek to address this knowledge gap using a suite of instruments to detect and document tubes in a terrestrial analog study at Lava Beds National Monument, California, USA. Here we describe the results of ground penetrating radar (GPR) profiles and light detection and ranging (LiDAR) scans. Surveys were conducted from the surface and within four lava tubes (Hercules Leg, Skull, Valentine and, Indian Well Caves) with varying flow composition, shape, and complexity. Results are shown across segments of these tubes where the tubes are 10 m in height and the ceilings are 1 - 10 m below the surface. The GPR profiles over the tubes are, as expected, complex, due to scattering from fractures in roof material and three-dimensional heterogeneities. Point clouds derived from the LiDAR scans of both the interior and exterior of the lava tubes provide precise positioning of the tube geometry and depth of the ceiling and floor with respect to the surface topography. GPR profiles over LiDAR-mapped tube cross-sections are presented and compared against synthetic models of radar response to the measured geometry. This comparison will help to better understand the origins of characteristic features in the radar profiles. We seek to identify the optimal data processing and migration approaches to aid lava tube exploration of planetary surfaces.

Detection and delineation of underground septic tanks in sandy terrain using ground penetrating radar

Science.gov (United States)

Omolaiye, Gabriel Efomeh; Ayolabi, Elijah A.

2010-09-01

A ground penetrating radar (GPR) survey was conducted on the Lekki Peninsula, Lagos State, Nigeria. The primary target of the survey was the delineation of underground septic tanks (ST). A total of four GPR profiles were acquired on the survey site using Ramac X3M GPR equipment with a 250MHz antenna, chosen based on the depth of interest and resolution. An interpretable depth of penetration of 4.5m below the surface was achieved after processing. The method accurately delineated five underground ST. The tops of the ST were easily identified on the radargram based on the strong-amplitude anomalies, the length and the depths to the base of the ST were estimated with 99 and 73 percent confidence respectively. The continuous vertical profiles provide uninterrupted subsurface data along the lines of traverse, while the non-intrusive nature makes it an ideal tool for the accurate mapping and delineation of underground utilities.

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.

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

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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.

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

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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.

IL-1β and TNFα inhibit GPR120 (FFAR4) and stimulate GPR84 (EX33) and GPR41 (FFAR3) fatty acid receptor expression in human adipocytes: implications for the anti-inflammatory action of n-3 fatty acids.

Science.gov (United States)

Muredda, Laura; Kępczyńska, Małgorzata A; Zaibi, Mohamed S; Alomar, Suliman Y; Trayhurn, Paul

2018-05-01

Regulation of the expression of GPCR fatty acid receptor genes has been examined in human adipocytes differentiated in culture. TNFα and IL-1β induced a marked reduction in GPR120 expression, mRNA level falling 17-fold at 24 h in adipocytes incubated with TNFα. In contrast, GPR84 mRNA was dramatically increased by these cytokines (>500-fold for IL-1β at 4 h); GPR41 expression was also stimulated. Rosiglitazone did not affect GPR84 expression, but GPR120 and GPR41 expression increased. Dexamethasone, insulin, linoleic and docosahexaenoic acids (DHA), and TUG891 (GPR120 agonist) had little effect on GPR120 and GPR84 expression. TUG891 did not attenuate the pro-inflammatory actions of TNFα and IL-1β. DHA slightly countered the actions of IL-1β on CCL2, IL6 and ADIPOQ expression, though not on secretion of these adipokines. GPR120 and GP84 gene expression in human adipocytes is highly sensitive to pro-inflammatory mediators; the inflammation-induced inhibition of GPR120 expression may compromise the anti-inflammatory action of GPR120 agonists.

Developing an Efficient and Cost Effective Ground-Penetrating Radar Field Methodology for Subsurface Exploration and Mapping of Cultural Resources on Public Lands

National Research Council Canada - National Science Library

Conyers, Lawrence B

2006-01-01

.... A new, emerging technology is the use of ground penetrating radar (GPR). However, in using this device due to the number of variables that can impact energy penetration and resolution, researchers are often not guaranteed a successful survey...

Combination of GPR with other NDT techniques in different fields of application - COST Action TU1208

Science.gov (United States)

Solla, Mercedes; Pérez-Gracia, Vega; Fontul, Simona; Santos-Assunçao, Sonia; Kucukdemirci, Melda

2017-04-01

During the last decades, there has been a continuous increase in the use of non-destructive testing (NDT) applied to many aspects related to civil engineering and other fields such as geology or sedimentology, archaeology and either monument or cultural heritage. This is principally due to the fact that most NDT methods work remotely, that is, without direct contact, while adding information of non-visible areas. Particularly, geophysics has significantly benefited the procedures for inspection and also, successfully solved some of the limitations of traditional methods such as a lack of objectiveness, destructive testing, loss of safety during infrastructure inspection, and also, low rates of production. The different geophysical methodologies are based on the measurement of physical properties of media. However, all geophysical methods are sensitive to different physical parameters and the success of these methods is related to the nature of the buried features themselves, in terms of their physical and geometric properties, soil conditions, operational factors such as the sensitivity of equipment and etc. Consequently, taking into account all of these factors, to obtain reliable and complementary results, multiple geophysical methods rather than single method and moreover data integration approaches are recommended to provide accurate interpretations. This work presents some examples of combination of Ground-Penetrating Radar (GPR) with other NDT techniques in different fields of application (pavements/railways, archaeological sites, monuments, and stratigraphy in beaches and bathymetries). An example of combination of GPR and Falling Weight Deflectometer (FWD) to assess the bearing capacity of flexible pavement is described as the most efficient structural evaluation of pavements and one of the most commonly applications of the methods on civil engineering inspections. Results of archaeogeophysical field surveys in Turkey are also included by combining the most

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.

Numerical Study of Planar GPR Antenna Measurements

DEFF Research Database (Denmark)

Meincke, Peter; Hansen, Thorkild

2004-01-01

The formulation of planar near-field measurements of GPR antennas determines the plane-wave spectra of the GPR antenna in terms of measurements obtained with a buried probe as the GPR antenna moves over a scan plane on the ground. A numerical study investigates how the formulation is affected by (1...

Proposing New Methods to Enhance the Low-Resolution Simulated GPR Responses in the Frequency and Wavelet Domains

Directory of Open Access Journals (Sweden)

Reza Ahmadi

2014-12-01

Full Text Available To date, a number of numerical methods, including the popular Finite-Difference Time Domain (FDTD technique, have been proposed to simulate Ground-Penetrating Radar (GPR responses. Despite having a number of advantages, the finite-difference method also has pitfalls such as being very time consuming in simulating the most common case of media with high dielectric permittivity, causing the forward modelling process to be very long lasting, even with modern high-speed computers. In the present study the well-known hyperbolic pattern response of horizontal cylinders, usually found in GPR B-Scan images, is used as a basic model to examine the possibility of reducing the forward modelling execution time. In general, the simulated GPR traces of common reflected objects are time shifted, as with the Normal Moveout (NMO traces encountered in seismic reflection responses. This suggests the application of Fourier transform to the GPR traces, employing the time-shifting property of the transformation to interpolate the traces between the adjusted traces in the frequency domain (FD. Therefore, in the present study two post-processing algorithms have been adopted to increase the speed of forward modelling while maintaining the required precision. The first approach is based on linear interpolation in the Fourier domain, resulting in increasing lateral trace-to-trace interval of appropriate sampling frequency of the signal, preventing any aliasing. In the second approach, a super-resolution algorithm based on 2D-wavelet transform is developed to increase both vertical and horizontal resolution of the GPR B-Scan images through preserving scale and shape of hidden hyperbola features. Through comparing outputs from both methods with the corresponding actual high-resolution forward response, it is shown that both approaches can perform satisfactorily, although the wavelet-based approach outperforms the frequency-domain approach noticeably, both in amplitude and

Evaluation of wood structure using GPR with FO method - Effect of moisture, fibers direction and density

Science.gov (United States)

Chinh Maï, Tien; Reci, Hamza; Sbartaï, Zoubir Mehdi; Pajewski, Lara; Marciniak, Marian

2017-04-01

This work deals with the potential of GPR method in the evaluation of wood structure in relation with density of wood (different wood species), the orientation of fibers and water content (Maï et al., 2015; Reci et al., 2016). The system of measurements is the georadar type (GPR-ground penetrating radar) composed of an electromagnetic signal generator (SIR 3000 of GSSI), and one couple of antennas, one Transmitter (T) and a Receiver (R) of 1.5GHz center frequency, located in the same box in a fixed distance of 6cm. Six wood samples are tested, three samples of Epicea and three samples of Pine. To compare and analyze the results of dielectric constants, we have used the data on three principal directions (Transvesal, Longitudinal and Radial). We note that the dielectric constant of wood increases with the moisture by mass as a consequence of increasing polarization and the conduction phenomena. This effect is more distinguished when the electric field is polarized parallel to the fibers than in perpendicular direction. The smallest contrasts are observed in the radial direction. We conclude that is more appropriate to evaluate the water content along the parallel direction of fibers. In this case we observe the maximum of contrasts of dielectric contrasts between dry and humidity states. Differences on dielectric constant, spectras and amplitudes are taken between different wood samples. Knowing that the dielectric constant is related to the capacity of polarizing (dependent on the water quantity), the increasing of water content could explain the difference of values obtained for the dielectric constants between two kinds of wood. Acknowledgement The Authors are grateful to COST - European Cooperation in Science and Technology (www.cost.eu) for funding the Action TU1208 "Civil engineering applications of Ground Penetrating Radar" (www.GPRadar.eu). We acknowledge also the French National Research Agency (ANR) for supporting this study through the Xylo-plate project

VISUAL INSPECTION OF WATER LEAKAGE FROM GROUND PENETRATING RADAR RADARGRAM

OpenAIRE

N. N. Halimshah; A. Yusup; Z. Mat Amin; M. D. Ghazalli

2015-01-01

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 effic...

On thin ice: ground penetrating radar improves safety for seismic crews in frigid arctic darkness

Energy Technology Data Exchange (ETDEWEB)

Smith, M.

2002-02-01

The fact that workers are pushing the limits of the Canadian Arctic's ice is more than act of faith; it is the result of rapidly advancing technologies that are taking the guesswork, and therefore the risk, out of icetop exploration. The most important element to improve safety in recent years has been the increased use of ground penetrating radar (GPR) which allows the most detailed images yet of ice thickness. It is an absolutely invaluable tool for allowing vehicles to drive along the ice roads up the rivers and offshore, with significantly reduced risk for the people involved. GPR is an essential part of the equipment usually tied into global positioning system (GPS) and and geographic information system (GIS). The collected GPS and GPR data are loaded into the workstation and merged to produce a GIS map where the colored map of ice thickness is overlaid over satellite image or aerial photographs. Ground penetrating radar was first used in Austria in 1929 to measure glacial ice thickness. It fell into disuse during the 1950s but the technology advanced rapidly in subsequent years; it was used as part of Apollo 17's lunar sounder experiment in 1972. It is particularly useful in northern Arctic regions to determine near-surface thickness. With pipeline developments in the active planning stages, measuring the thickness of ice is more vital than ever; investors will not commit to multi-billion dollar projects before the resource base is fully delineated.

Ground penetrating radar geologic field studies of the ejecta of Barringer Meteorite Crater, Arizona, as a planetary analog

Science.gov (United States)

Russell, Patrick S.; Grant, John A.; Williams, Kevin K.; Carter, Lynn M.; Brent Garry, W.; Daubar, Ingrid J.

2013-09-01

penetrating radar (GPR) has been a useful geophysical tool in investigating a variety of shallow subsurface geological environments on Earth. Here we investigate the capabilities of GPR to provide useful geologic information in one of the most common geologic settings of planetary surfaces, impact crater ejecta. Three types of ejecta are surveyed with GPR at two wavelengths (400 MHz, 200 MHz) at Meteor Crater, Arizona, with the goal of capturing the GPR signature of the subsurface rock population. In order to "ground truth" the GPR characterization, subsurface rocks are visually counted and measured in preexisting subsurface exposures immediately adjacent to and below the GPR transect. The rock size-frequency distribution from 10 to 50 cm based on visual counts is well described by both power law and exponential functions, the former slightly better, reflecting the control of fragmentation processes during the impact-ejection event. GPR counts are found to overestimate the number of subsurface rocks in the upper meter (by a factor of 2-3x) and underestimate in the second meter of depth (0.6-1.0x), results attributable to the highly scattering nature of blocky ejecta. Overturned ejecta that is fractured yet in which fragments are minimally displaced from their complement fragments produces fewer GPR returns than well-mixed ejecta. The use of two wavelengths and division of results into multiple depth zones provides multiple aspects by which to characterize the ejecta block population. Remote GPR measurement of subsurface ejecta in future planetary situations with no subsurface exposure can be used to characterize those rock populations relative to that of Meteor Crater.

Polyunsaturated fatty acid receptors, GPR40 and GPR120, are expressed in the hypothalamus and control energy homeostasis and inflammation

DEFF Research Database (Denmark)

Dragano, Nathalia R V; Solon, Carina; Ramalho, Albina F

2017-01-01

BACKGROUND: The consumption of large amounts of dietary fats is one of the most important environmental factors contributing to the development of obesity and metabolic disorders. GPR120 and GPR40 are polyunsaturated fatty acid receptors that exert a number of systemic effects that are beneficial...... for metabolic and inflammatory diseases. Here, we evaluate the expression and potential role of hypothalamic GPR120 and GPR40 as targets for the treatment of obesity. METHODS: Male Swiss (6-weeks old), were fed with a high fat diet (HFD, 60% of kcal from fat) for 4 weeks. Next, mice underwent stereotaxic...... the treatment period. At the end of the experiment, the hypothalamus was collected for real-time PCR analysis. RESULTS: We show that both receptors are expressed in the hypothalamus; GPR120 is primarily present in microglia, whereas GPR40 is expressed in neurons. Upon intracerebroventricular treatment, GW9508...

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

Mapping of near surface fold structures with GPR and ERT near Steinbrunn (Northern Burgenland, Austria)

Science.gov (United States)

Kreutzer, Ingrid; Chwatal, Werner; Häusler, Hermann; Scheibz, Jürgen; Steirer, Fritz

2014-05-01

In the transition zone between the southern Vienna Basin and the Eisenstadt basin, close to Wr. Neustadt, spectacular fold structures are exposed in the former sand pit of Steinbrunn. The succession of Upper Pannonian age consists of decimetre to meter thick sandy, silty and clayey beds, which are overlain by sandstone beds (Grundtner et al., 2009). The anticline and syncline structures were interpreted as of gravitational origin by Exner et al. (2009), and reinterpreted as of tectonic origin by Häusler (2012a). In order to gain a more detailed insight to the three dimensional distribution and orientation of the folds high resolution geophysics such as electrical resistivity tomography (ERT), ground penetrating radar (GPR) and electromagnetics (EM) were applied to map the surroundings of the sandpit. The ERT- and EM-profiles show that the uppermost layer is more clayey northwest and sandier southeast of the sandpit. This is important for the GPR because clay attenuates the radar signals and therefore no clear layering of the subsurface could be mapped in these areas. In order to directly compare ERT and GPR results with the lithology of the fold structures observed in the sandpit, a reference profile on top of the 140 m long wall of the sandpit was performed. Both methods clearly reveal fold structures paralleling the folded Pannonian strata of the outcrop. While the GPR data displays boundaries and their geometry in the succession, the resistivities in the ERT portrays a more smoothened image of the observed fold structure. In almost all GPR profiles wavelike structures are visible with axes in northern direction and dome-shaped structures with axes in eastern direction, deepening towards the west. In conclusion this pattern is comparable to sections of rounded buckle folds. Although there are clayey areas wave-like and dome-like reflections can be followed in the GPR profiles over a distance of several hundred meters. This is confirmed by the ERT profiles

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

Detection of Subsurface Defects in Levees in Correlation to Weather Conditions Utilizing Ground Penetrating Radar

Science.gov (United States)

Martinez, I. A.; Eisenmann, D.

2012-12-01

Ground Penetrating Radar (GPR) has been used for many years in successful subsurface detection of conductive and non-conductive objects in all types of material including different soils and concrete. Typical defect detection is based on subjective examination of processed scans using data collection and analysis software to acquire and analyze the data, often requiring a developed expertise or an awareness of how a GPR works while collecting data. Processing programs, such as GSSI's RADAN analysis software are then used to validate the collected information. Iowa State University's Center for Nondestructive Evaluation (CNDE) has built a test site, resembling a typical levee used near rivers, which contains known sub-surface targets of varying size, depth, and conductivity. Scientist at CNDE have developed software with the enhanced capabilities, to decipher a hyperbola's magnitude and amplitude for GPR signal processing. With this enhanced capability, the signal processing and defect detection capabilities for GPR have the potential to be greatly enhanced. This study will examine the effects of test parameters, antenna frequency (400MHz), data manipulation methods (which include data filters and restricting the range of depth in which the chosen antenna's signal can reach), and real-world conditions using this test site (such as varying weather conditions) , with the goal of improving GPR tests sensitivity for differing soil conditions.

SEA ICE THICKNESS MEASUREMENT BY GROUND PENETRATING RADAR FOR GROUND TRUTH OF MICROWAVE REMOTE SENSING DATA

Directory of Open Access Journals (Sweden)

M. Matsumoto

2018-04-01

Full Text Available Observation of sea ice thickness is one of key issues to understand regional effect of global warming. One of approaches to monitor sea ice in large area is microwave remote sensing data analysis. However, ground truth must be necessary to discuss the effectivity of this kind of approach. The conventional method to acquire ground truth of ice thickness is drilling ice layer and directly measuring the thickness by a ruler. However, this method is destructive, time-consuming and limited spatial resolution. Although there are several methods to acquire ice thickness in non-destructive way, ground penetrating radar (GPR can be effective solution because it can discriminate snow-ice and ice-sea water interface. In this paper, we carried out GPR measurement in Lake Saroma for relatively large area (200 m by 300 m, approximately aiming to obtain grand truth for remote sensing data. GPR survey was conducted at 5 locations in the area. The direct measurement was also conducted simultaneously in order to calibrate GPR data for thickness estimation and to validate the result. Although GPR Bscan image obtained from 600MHz contains the reflection which may come from a structure under snow, the origin of the reflection is not obvious. Therefore, further analysis and interpretation of the GPR image, such as numerical simulation, additional signal processing and use of 200 MHz antenna, are required to move on thickness estimation.

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

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.

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.

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

This work aims at disseminating the ongoing research activities and third-year results of the COST (European COoperation in Science and Technology) Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar." About 350 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, Colombia, Egypt, Hong Kong, Jordan, Israel, Philippines, Russia, Rwanda, Ukraine, and United States of America. In September 2014, TU1208 has been recognised 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

Attribute analyses of gpr data for detecting and identifying heavy minerals

Science.gov (United States)

Catakli, Aycan

Attribute analyses have been used successfully in seismic applications for many years. In this study, the application of the attribute analyses to Ground Penetrating Radar (GPR) data has been proposed to detect and identify heavy minerals within the Moon soil (regolith). Lunar samples are mostly composed of heavy minerals such as ilmenite, plagioclase, olivine and pyroxene, a characteristic that makes lunar soil a source for elements such as titanium, oxygen and iron. The main goal of this study is to demonstrate the use of GPR method for detecting and mapping heavy minerals concentrations. The attribute analyses used in this study are Attenuation Analysis (AA), Complex Trace Analysis (CTA), Texture Analysis (TA) and Center Frequency Destitution (CFD). Attribute analysis was applied to both synthetic models and prototype laboratory measurements to study its application to GPR data. The results indicate that the attribute analyses of GPR data can be useful to provide valuable subsurface information. The findings of AA show that attenuation values are function of mineralogy of the subsurface. This could be applicable to Moon and Mars in addition to Earth environment to explore their near-surface soils. CTA can successfully estimate the location of heavy mineral samples embedded inside host medium through the variation of reflected energy around buried sample and sharpen the reflecting interface. Results indicate that as the amount of the buried heavy minerals increases, the value of CTA parameters (Normal distribution of amplitude spectra `NDoAS' and tau-parameter) proportionally increase. TA measures combined can be used as an enhanced interpretation tool. The texture results show that heavy mineral concentrations can be identified by the high contrast, entropy, autocorrelation, correlation, cluster, dissimilarity, standard deviation, variance and low energy, maximum probability, and homogeneity. The measures also help in highlighting the edge of the buried samples

Minimising street work disruption by mapping cavities derived from 3D GPR-data: a new sewerage project in Torrente (Valencia, Spain)

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Valls, Ana; Garcia, Francisco; Ramirez, Manuel; Benlloch, Javier

2015-04-01

Ground penetrating radar is usually employed for non-destructive detection of cavities in karst areas and road maintenance. This paper describes the inspection for cavity detection in a street located in Torrente (Valencia, Spain) where a new sewerage project was planned. Torrente population growth (more than 80,000 inhabitants last year) has caused urban development southwards from its downtown. According to municipality geologic configuration, new urbanized areas are located in mountains composed of limestone with presence of karst systems. During excavation work for a sewerage system installation, a 4 x 2 x 1.5 m shallow cave was found in one planned street. For this reason, digging activities were stopped and a GPR survey was carried out on the street. A 1x1 m grid was collected using a GSSI SIR-3000 equipment. A 400 MHz frequency antenna was used for reaching 2.5 m approx. depth, attending the characteristics of the discovered cave and the excavation project depth. GPR records were calibrated in situ, thanks to the unearthed cavity. The 3D GPR-data interpretation mapped several caves only on one side of the street. The detected cavities coincided with the sewerage system layout. These underground spaces were isolated from each other, as small individual karst caves. The outcomes of this study allowed the modification of the sewerage project. Therefore, the sewerage system layout was moved to the other side of the street where no cavities were detected with the GPR survey. GPR is proved to be an efficient tool to be taken into consideration by civil engineers and architects for designing new infrastructures (e.g. sewerage systems) in urban planning areas. We conclude GPR helps minimising cost, time and inconveniences to neighbourhood during excavation works, especially in cities.

EBI2, GPR18 and GPR17--three structurally related, but biologically distinct 7TM receptors

DEFF Research Database (Denmark)

Nørregaard, Kristine; Benned-Jensen, Tau; Rosenkilde, Mette Marie

2011-01-01

7TM receptors constitute one of the largest superfamilies of proteins in the human genome. They are involved in a large number of physiological and pathological processes in the human body and thus represent major and important drug targets for the pharmaceutical industry. Although the majority...... have been deorphanized, many remain orphan, and these orphan receptors constitute a large pool of potential drug targets. This review focuses on one of these orphan targets, the Epstein-Barr Virus-induced receptor 2, EBI2 (or GPR183), together with two structurally related receptors, GPR17 and GPR18...

2D and 3D GPR imaging of structural ceilings in historic and existing constructions

Science.gov (United States)

Colla, Camilla

2014-05-01

GPR applications in civil engineering are to date quite diversified. With respect to civil constructions and monumental buildings, detection of voids, cavities, layering in structural elements, variation of geometry, of moisture content, of materials, areas of decay, defects, cracks have been reported in timber, concrete and masonry elements. Nonetheless, many more fields of investigation remain unexplored. This contribution gives an account of a variety of examples of structural ceilings investigation by GPR radar in reflection mode, either as 2D or 3D data acquisition and visualisation. Ceilings have a pre-eminent role in buildings as they contribute to a good structural behaviour of the construction. Primarily, the following functions can be listed for ceilings: a) they carry vertical dead and live loads on floors and distribute such loads to the vertical walls; b) they oppose to external horizontal forces such as wind loads and earthquakes helping to transfer such forces from the loaded element to the other walls; c) they contribute to create the box skeleton and behaviour of a building, connecting the different load bearing walls and reducing the slenderness and flexural instability of such walls. Therefore, knowing how ceilings are made in specific buildings is of paramount importance for architects and structural engineers. According to the type of building and age of construction, ceilings may present very different solutions and materials. Moreover, in existing constructions, ceilings may have been substituted, modified or strengthened due to material decay or to change of use of the building. These alterations may often go unrecorded in technical documentation or technical drawings may be unavailable. In many cases, the position, orientation and number of the load carrying elements in ceilings may be hidden or not be in sight, due for example to the presence of false ceilings or to technical plants. GPR radar can constitute a very useful tool for

Exploring applications of GPR methodology and uses in determining floodplain function of restored streams in the Gulf Coastal Plain, Alabama

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Eckes, S. W.; Shepherd, S. L.

2017-12-01

Accurately characterizing subsurface structure and function of remediated floodplains is indispensable in understanding the success of stream restoration projects. Although many of these projects are designed to address increased storm water runoff due to urbanization, long term monitoring and assessment are often limited in scope and methodology. Common monitoring practices include geomorphic surveys, stream discharge, and suspended sediment loads. These data are comprehensive for stream monitoring but they do not address floodplain function in terms of infiltration and through flow. Developing noninvasive methods for monitoring floodplain moisture transfer and distribution will aid in current and future stream restoration endeavors. Ground penetrating radar (GPR) has been successfully used in other physiographic regions for noninvasive and continuous monitoring of (1) natural geomorphic environments including subsurface structure and landform change and (2) soil and turf management to monitor subsurface moisture content. We are testing the viability of these existing methods to expand upon the broad capabilities of GPR. Determining suitability will be done in three parts using GPR to (1) find known buried objects of typical materials used in remediation at measured depths, (2) understand GPR functionality in varying soil moisture content thresholds on turf plots, and (3) model reference, remediated, and impacted floodplains in a case study in the D'Olive Creek watershed located in Baldwin County, Alabama. We hypothesize that these methods will allow us to characterize moisture transfer from precipitation and runoff to the floodplain which is a direct function of floodplain health. The need for a methodology to monitor floodplains is widespread and with increased resolution and mobility, expanding GPR applications may help streamline remediation and monitoring practices.

Prediction of buried mine-like target radar signatures using wideband electromagnetic modeling

Energy Technology Data Exchange (ETDEWEB)

Warrick, A.L.; Azevedo, S.G.; Mast, J.E.

1998-04-06

Current ground penetrating radars (GPR) have been tested for land mine detection, but they have generally been costly and have poor performance. Comprehensive modeling and experimentation must be done to predict the electromagnetic (EM) signatures of mines to access the effect of clutter on the EM signature of the mine, and to understand the merit and limitations of using radar for various mine detection scenarios. This modeling can provide a basis for advanced radar design and detection techniques leading to superior performance. Lawrence Livermore National Laboratory (LLNL) has developed a radar technology that when combined with comprehensive modeling and detection methodologies could be the basis of an advanced mine detection system. Micropower Impulse Radar (MIR) technology exhibits a combination of properties, including wideband operation, extremely low power consumption, extremely small size and low cost, array configurability, and noise encoded pulse generation. LLNL is in the process of developing an optimal processing algorithm to use with the MIR sensor. In this paper, we use classical numerical models to obtain the signature of mine-like targets and examine the effect of surface roughness on the reconstructed signals. These results are then qualitatively compared to experimental data.

Short-chain free fatty acid receptors FFA2/GPR43 and FFA3/GPR41 as new potential therapeutic targets

DEFF Research Database (Denmark)

Ulven, Trond

2012-01-01

The deorphanization of the free fatty acid (FFA) receptors FFA1 (GPR40), FFA2 (GPR43), FFA3 (GPR41), GPR84, and GPR120 has made clear that the body is capable of recognizing and responding directly to nonesterified fatty acid of virtually any chain length. Colonic fermentation of dietary fiber...... produces high concentrations of the short-chain fatty acids (SCFAs) acetate, propionate and butyrate, a process which is important to health. The phylogenetically related 7-transmembrane (7TM) receptors free fatty acid receptor 2 (FFA2) and FFA3 are activated by these SCFAs, and several lines of evidence...... in general have properties that make them less than ideal as such tools, but published patent applications indicate that better tool compounds might soon become available which should enable studies critical to validate the receptors as new drug targets....

Interpretation of the distortion of ground-penetrating radar propagated and reflected waves - development of a multi-frequency tomography; Interpretation de la distorsion des signaux georadar propages et reflechis. Developpement d'une tomographie par bandes de frequence

Energy Technology Data Exchange (ETDEWEB)

Hollender, F

1999-07-01

Within the framework of research for waste disposal in deep geological formations, the French agency for nuclear waste management (ANDRA) has to dispose of non-destructive investigation methods to characterize the medium. Ground penetrating radar (GPR) could be used for this purpose in the case of granitic sites. The work presented here deals with this geophysical method. The classical interpretation of GPR data consists in the localization of geological discontinuities by signal amplitude or arrival time analysis. The main objective of our studies is the interpretation of the radar wave distortion (due to propagation and reflection phenomena), not only to localize discontinuities but also to contribute to their identification. Three preliminary studies have been carried out in order to understand on the one hand, the complexity of the electromagnetic phenomena in the geological medium at radar frequency, and on the other hand, the radar equipment constraints. First, the dispersion and the attenuation characterized by a Q variable factor of the GPR waves are shown with the support of dielectric laboratory measurements. A model, which only requires three parameters, is proposed in order to describe this behavior. Second, the radiation patterns of borehole radar antenna are studied. We show that the amplitude and frequency content of the emitted signal are variable versus the emission angle. An analytical method is proposed to study these phenomena. Finally, instrumental drifts of GPR equipment are studied. Emission time, sampling frequency and amplitude fluctuations are described. These elements are taken into account for the processing of propagated signals by tomographic inversion. Medium anisotropy and borehole trajectory errors are inserted in algorithms in order to cancel artifacts which compromised the previous interpretation. A pre-processing method, based on wave separation algorithm, is applied on data in order to increase tomogram resolution. A new

Survey of Electrical Imaging and Geo radar on Landslides Investigation at Taman Hillview, Ampang, Selangor

International Nuclear Information System (INIS)

Umar Hamzah; Nurul Fairuz Diyana Bahrudin; Mohd Azmi Ismail; Amry Amin Abbas

2009-01-01

Electrical resistivity and Ground Penetrating Radar (GPR) surveys were carried out at Taman Hill View, Ampang, Selangor landslide area. This landslide site was a part of three similar landslides which occurred at Bukit Antarabangsa, Hulu Klang, Selangor. The landslide had occurred along the road to Bukit Antarabangsa and Athenaeum Tower. The objectives of these studies were to characterise the sliding material and to determine the depth of bedrock below the sliding surface using the electrical resistivity imaging technique as well as to recognise the fractured or weak zone using the GPR technique. The spacing between electrodes used in the survey was 2 to 2.5 m and the survey lines were chosen close to the borehole locations. With a total of 41 electrodes and spacing between each electrode of 2 to 2.5 m, the maximum current electrode spacing in this survey would be between 80-100 m resulting in the deepest subsurface depth investigated approximately at 20 to 25 m. A 100 MHz electromagnetic wave was used in the Ground Penetration Radar survey. The resistivity imaging result showed the weathered granite profile with resistivity value ranging from 2 to 7000 Ωm. The patterns also show that this area had a lot of fractured or weak zones up to a depth of 4 to 5 m based on the occurrence of low resistivities zones in between the high resistivities. These highly fractured and faulted zones also appeared in the GPR sections as shown by the presence of shifted reflectors and layer discontinuity. (author)

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.

Wideband Cavity Backed Spiral Antenna for Stepped Frequency Ground Penetrating Radar

DEFF Research Database (Denmark)

Thaysen, Jesper; Jakobsen, Kaj Bjarne; Lenler-Eriksen, Hans-Rudolph

2005-01-01

A 1.7 turn cavity backed coplanar waveguide to coplanar strip-fed logarithmic uniplanar spiral antenna is presented and compared to a 1.5 turn spiral antenna. The 1.7 turn spiral antenna has a wide beamwidth, are circular polarised and has a bandwidth with a return loss better than 6 dB in the fr......B in the frequency band from 0.25 GHz to 4.5 GHz (18:1). The antenna is useful for Ground Penetrating Radar (GPR)....

Application of Coupled-Wave Wentzel-Kramers-Brillouin Approximation to Ground Penetrating Radar

OpenAIRE

Igor Prokopovich; Alexei Popov; Lara Pajewski; Marian Marciniak

2017-01-01

This paper deals with bistatic subsurface probing of a horizontally layered dielectric half-space by means of ultra-wideband electromagnetic waves. In particular, the main objective of this work is to present a new method for the solution of the two-dimensional back-scattering problem arising when a pulsed electromagnetic signal impinges on a non-uniform dielectric half-space; this scenario is of interest for ground penetrating radar (GPR) applications. For the analytical description of the s...

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

Expression and Role of GPR87 in Urothelial Carcinoma of the Bladder

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Yoshiyuki Kakehi

2013-06-01

Full Text Available The orphan GPR87 has recently been matched with its ligand LPA, which is a lipid mediator with multiple physiological functions, including cancer cell proliferation. This study aimed to clarify the role of GPR87 in urothelial carcinoma of the bladder. GPR87 expression was assessed in seven human bladder cancer cell lines. A replication-deficient recombinant adenoviral vector expressing shRNA targeting GPR87 (Ad-shGPR87, was constructed. Gene silencing was carried out using Ad-shGPR87. Immunohistochemical analysis was performed for transurethral resection of bladder tumor samples from 71 patients with non-muscle-invasive bladder cancer. We observed GPR87 expression in five of the seven cell lines, and silencing GPR87 gene expression significantly reduced cell viability. GPR87 expression was positive in 38 (54% of 71 tumors. Ki-67 index was associated with positive GPR87 staining status (p < 0.0001. Patients with GPR87-positive tumors had shorter intravesical recurrence-free survival than those with GPR87-negative tumors (p = 0.010. Multivariate analysis revealed that GPR87 staining status was an independent prognostic parameter for intravesical recurrence (p = 0.041. Progression from non-muscle-invasive to muscle-invasive tumor was more frequently observed in patients with GPR87-positive tumors, although this trend did not reach statistical significance (p = 0.056. These results warrant further prospective studies to clarify the role of GPR87 expression in intravesical recurrence and progression in bladder cancer.

Investigating hydrocarbon contamination using ground penetrating radar

International Nuclear Information System (INIS)

Roest, P.B. van der; Brasser, D.J.S.; Wagebaert, A.P.J.; Stam, P.H.

1996-01-01

The increasing costs of remediating contaminated sites has stimulated research for cost reducing techniques in soil investigation and clean-up techniques. Under the traditional approach soil borings and groundwater wells are used to investigate contaminated soil. These are useful tools to determine the amount and characteristics of the contamination, but they are inefficient and costly in providing information on the location and extent of contamination as they only give information on one point. This often leads to uncertainty in estimating clean-up costs or, even worse, to unsuccessful clean-ups. MAP Environmental Research has developed a technology using Ground Penetrating Radar (GPR) in combination with in-house developed software to locate and define the extent of hydrocarbon contamination. With this technology, the quality of site investigation is increased while costs are reduced. Since 1994 MAP has been improving its technology and has applied it to over 100 projects, which all have been checked afterwards by conventional drilling. This paper gives some general characteristics of the method and presents a case study. The emphasis of this paper lies on the practical application of GPR to hydrocarbon contamination detection

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

Ground Penetrating Radar (GPR) is mainly used for scientific research in coastal geology in the Institute of Ecology at Tallinn University. We currently use SIR-3000 radar with 100, 270 , 300 and 500 MHz antennae. Our main targets have been detecting the thickness of soil and sand layers and finding out the layers in coastal sediments which reflect extreme storm events. Our GPR studies in various settings have suggested that the internal structures of the ridge-dune complexes are dominated by numerous layers dipping in various directions. Such information helps us to reconstruct and understand prevailing processes during their formation (e.g. seaward dipping lamination in coastal ridge-dune complexes indicating cross-shore and wave-induced transport of the sediments). Currently, we are trying to elaborate methodology for distinguishing the differences between aeolian and wave transported sediments by using GPR. However, paludified landscapes (often covered by water), very rough surface (numerous bushes and soft surface), moderate micro topography has slowed this process significantly. Moreover, we have been able to use GPR during the winter period (applied on ice or snow) and compare the quality of our results with the measurements taken during the summer period. We have found that smooth surface (in winter) helps detecting very strong signal differences (border between different sediment types - sand, peat, silt, etc.) but reduces the quality of the signal to the level where the detection of sedimentation patterns within one material (e.g. tilted layers in sand) is difficult. We have carried out several other science-related studies using GPR. These studies include determining the thickness of peat layer in bogs (to calculate the volume of accumulated peat or to find most suitable locations for coring), measuring the thickness of mud and gyttja layer in lakes (to find most suitable locations for coring, reconstructing initial water level of the lake or calculating

Accuracy of three-dimensional glacier surface volocities derived from radar interfeometry and ice-soundin radar measurements

DEFF Research Database (Denmark)

Mohr, Johan Jacob; Reeh, Niels; Madsen, Søren Nørvang

2003-01-01

We present a method for analyzing the errors involved in measuring three-dimensional glacier velocities with interferometric radar. We address the surface-parallel flow assumption and an augmented approach with a flux-divergence (FD) term. The errors in an interferometric ERS-1/-2 satellite radar...... dataset with ascending- and descending-orbit data covering Storstrommen glacier, northeast Greenland, are assessed. The FD error assessment is carried out on airborne 60 MHz ice-sounding radar data from the same area. A simple model of an interferometric radar system is developed and analyzed. The error...... sources considered include phase noise, atmospheric distortions, baseline calibration errors, a dry snow layer, and the stationary-flow assumption used in differential interferometry. The additional error sources in the analysis of FD errors are noise, bias and unknown variations of the ice thickness...

Resolving precipitation-induced water content profiles through inversion of dispersive GPR data

Science.gov (United States)

Mangel, A. R.; Moysey, S. M.; Van Der Kruk, J.

2015-12-01

Ground-penetrating radar (GPR) has become a popular tool for monitoring hydrologic processes. When monitoring infiltration, the thin wetted zone that occurs near the ground surface at early times may act as a dispersive waveguide. This low-velocity layer traps the GPR waves, causing specific frequencies of the signal to travel at different phase velocities, confounding standard traveltime analysis. In a previous numerical study we demonstrated the potential of dispersion analysis for estimating the depth distribution of waveguide water contents. Here, we evaluate the effectiveness of the methodology when applying it to experimental time-lapse dispersive GPR data collected during a laboratory infiltration experiment in a relatively homogenous soil. A large sand-filled tank is equipped with an automated gantry to independently control the position of 1000 MHz source and receiver antennas. The system was programmed to repeatedly collect a common mid-point (CMP) profile at the center of the tank followed by two constant offset profiles (COP) in the x and y direction. Each collection was completed in 30 s and repeated 50 times during a 28 min experiment. Two minutes after the start of measurements, the surface of the sand was irrigated at a constant flux rate of 0.006 cm/sec for 23 minutes. Time-lapse COPs show increases in traveltime to reflectors in the tank associated with increasing water content, as well as the development of a wetting front reflection. From 4-10 min, the CMPs show a distinct shingling characteristic that is indicative of waveguide dispersion. Forward models where the waveguide is conceptualized as discrete layers and a piece-wise linear function were used to invert picked dispersion curves for waveguide properties. We show the results from both inversion approaches for multiple dispersive CMPs and show how the single layer model fails to represent the gradational nature of the wetting front.

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

GPR 120: The Potential Target for Obesity Treatment.

Science.gov (United States)

Tanagho, Peter A; Shohdy, Kyrillus S

2016-01-01

G protein coupled receptor 120 (GPR120) is a class of receptors in the gastrointestinal tract (GIT) that is implicated in nutrient sensing and body weight regulation. Functions of GPR120 are thought to be mediated by the release of a group of hormones known as incretins, such as glucagon like peptide 1 (GLP-1) and gastric inhibitory polypeptide (GIP). We have searched PubMed with the keywords "GPR120","GLP-1" and "obesity". Relevant studies were retrieved and included in the review. Recently, many exogenous compounds have been investigated in their role in the release of GLP-1 and in causing weight loss in obese rats. However, some results question the putative role of GPR120 in metabolic homeostasis. Herein, we evaluate the potential use of GPR120 as a target receptor in obesity and found it to be ubiquitous throughout the GIT, with various functions in each site. In order to find the optimal drug, the role of GPR120 in each site needs to be defined and selectivity of the potential drug needs to be studied to ensure the success of this growing line of obesity management.

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

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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

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

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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.

Ground-penetrating radar in characterizing and monitoring waste-burial sites

International Nuclear Information System (INIS)

Sandness, G.A.; Kimball, C.S.

1982-02-01

Potential environmental hazards are associated with buried chemical and nuclear wastes because of the possibilities of inadvertent excavation or migration of toxic chemicals or radionuclides into groundwater or surface water bodies. Concern is often related to the fact that many existing waste burial sites have been found to be inadequately designed and/or poorly documented. New technology and innovative applications of current technology are needed to locate, characterize, and monitor the wastes contained in such sites. The work described in this paper is focused on the use of ground-penetrating radar (GPR) for those purposes

Radar sounding of bedrock and water table at Chalk River

International Nuclear Information System (INIS)

Annan, A.P.; Davis, J.L.

1979-01-01

When a spill of radioactive waste occurs, one of the main concerns is the flow pattern of ground water in the area of the spill. Ground probing radar is a relatively new geophysical technique which can provide high resolution data on the surficial geology and water distribution. The results of some preliminary radar experiments conducted at Chalk River Nuclear Laboratories (CRNL) of the Atomic Energy of Canada Limited (AECL), Chalk River, Ontario are presented. (auth)

Geophysical characterization of peatlands using crosshole GPR full-waveform inversion: Case study from a bog in northwestern Germany

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Schmäck, J.; Klotzsche, A.; Van Der Kruk, J.; Vereecken, H.; Bechtold, M.

2017-12-01

The characterization of peatlands is of particular interest, since areas with peat soils represent global hotspots for the exchange of greenhouse gases. Their effect on global warming depends on several parameters, like mean annual water level and land use. Models of greenhouse gas emissions and carbon accumulation in peatlands can be improved by including small-scale soil properties that e.g. act as gas traps and periodically release gases to the atmosphere during ebullition events. Ground penetrating radar (GPR) is well suited to non- or minimal invasively characterize and improve our understanding of dynamic processes that take place in the critical zone. It uses high frequency electromagnetic waves to image and characterize the dielectric permittivity and electrical conductivity of the critical zone, which can be related to hydrogeological properties like porosity, soil water content, salinity and clay content. In the last decade, the full-waveform inversion of crosshole GPR data has proved to be a powerful tool to improve the image resolution compared to standard ray-based methods. This approach was successfully applied to several different aquifers and was able to provide decimeter-scale resolution images including small-scale high contrast layers that can be related to zones of high porosity, zones of preferential flow or clay lenses. The comparison to independently measured e.g. logging data proved the reliability of the method. Here, for the first time crosshole GPR full-waveform inversion is used to image three peatland plots with different land use that are part of the "Ahlen-Falkenberger Moor peat bog complex" in northwestern Germany. The full-waveform inversion of the acquired data returned higher resolution images than standard ray-based GPR methods, and, is able to improve our understanding of subsurface structures. The comparison of the different plots is expected to provide new insights into gas content and gas trapping structures across different

Regulation of energy homeostasis via GPR120

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Atsuhiko eIchimura

2014-07-01

Full Text Available Free fatty acids (FFAs are fundamental units of key nutrients. FFAs exert various biological functions, depending on the chain length and degree of desaturation. Recent studies have shown that several FFAs act as ligands of G-protein-coupled receptors (GPCRs, activate intracellular signaling and exert physiological functions via these GPCRs. GPR120 (also known as free fatty acid receptor 4, FFAR4 is activated by unsaturated medium- to long-chain FFAs and has a critical role in various physiological homeostasis mechanisms such as incretin hormone secretion, food preference, anti-inflammation and adipogenesis. Recent studies showed that a lipid sensor GPR120 has a key role in sensing dietary fat in white adipose tissue and regulates the whole body energy homeostasis in both humans and rodents. Genetic study in human identified the loss-of-functional mutation of GPR120 associated with obesity and insulin resistance. In addition, dysfunction of GPR120 has been linked as a novel risk factor for diet-induced obesity. This review aims to provide evidence from the recent development in physiological function of GPR120 and discusses its functional roles in regulation of energy homeostasis and its potential as drug targets.

Void detection beneath reinforced concrete sections: The practical application of ground-penetrating radar and ultrasonic techniques

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Cassidy, Nigel J.; Eddies, Rod; Dods, Sam

2011-08-01

Ground-penetrating radar (GPR) and ultrasonic 'pulse echo' techniques are well-established methods for the imaging, investigation and analysis of steel reinforced concrete structures and are important civil engineering survey tools. GPR is, arguably, the more widely-used technique as it is suitable for a greater range of problem scenarios (i.e., from rebar mapping to moisture content determination). Ultrasonic techniques are traditionally associated with the engineering-based, non-destructive testing of concrete structures and their integrity analyses (e.g., flaw detection, shear/longitudinal velocity determination, etc). However, when used in an appropriate manner, both techniques can be considered complementary and provide a unique way of imaging the sub-surface that is suited to a range of geotechnical problems. In this paper, we present a comparative study between mid-to-high frequency GPR (450 MHz and 900 MHz) and array-based, shear wave, pulse-echo ultrasonic surveys using proprietary instruments and conventional GPR data processing and visualisation techniques. Our focus is the practical detection of sub-metre scale voids located under steel reinforced concrete sections in realistic survey conditions (e.g., a capped, relict mine shaft or vent). Representative two-dimensional (2D) sections are presented for both methods illustrating the similarities/differences in signal response and the temporal-spatial target resolutions achieved with each technique. The use of three-dimensional data volumes and time slices (or 'C-scans') for advanced interpretation is also demonstrated, which although common in GPR applications is under-utilised as a technique in general ultrasonic surveys. The results show that ultrasonic methods can perform as well as GPR for this specific investigation scenario and that they have the potential of overcoming some of the inherent limitations of GPR investigations (i.e., the need for careful antenna frequency selection and survey design in

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

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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

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

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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.

Modelling of EISS GPR's electrical and magnetic antennas for ExoMars mission

Science.gov (United States)

Biancheri-Astier, M.; Ciarletti, V.; Reineix, A.; Corbel, C.; Dolon, F.; Simon, Y.; Caudoux, C.; Lapauw, L.; Berthelier, Jj.; Ney, R.

2009-04-01

Despite several past and present missions to Mars, very little information is available on its subsurface. One of the scientific objectives of the European ExoMars mission (ESA) is to characterize the water / geochemical environment as a function of depth and investigate the planet subsurface to better understand the evolution and habitability of the planet. The electromagnetic survey of subsurface will provide a nondestructive way to probe the subsurface and look for potential deep liquid water reservoirs. The LATMOS (ex CETP) is currently developing a ground penetrating radar (GPR) called EISS "Electromagnetic Investigation of the Sub Surface", which is a enhanced version of the TAPIR "Terrestrial and Planetary Imaging Radar", developed in the frame of the Netlander mission cancelled in 2004. The GPR main objective is to perform sounding of the sub-surface down to kilometric depth. EISS is an impulse GPR operating, from the Martian surface, at HF frequencies (~ 2-4MHz) with a wide bandwidth (100kHz-5MHz). EISS can operate in four modes: impedance measurement, mono and bi-static survey, passive mode. The EISS innovative concept is based on the use of the fixed station (Lander) and mobile rover to conduct subsurface surveys of the area visited by the Rover. The work at HF frequencies, EISS uses a half-wave resistively loaded dipole electrical antenna i.e. two monopoles 35 meters long each to transmit (and also receive in mono-static mode) the signal. The resistive profile of the antenna follows a Wu-King profile which is optimized to transmit the pulse without noticeable distortion and avoid ringing. The two monopoles will be deployed in roughly opposite directions on the surface of Mars. The exact value of the direction of deployment for each monopole will be chosen in order to minimize the contact with the Lander structure, avoid obstacles and the solar panels still ensuring a good coverage of the whole area. In bi-static mode, the signal is received with a small

Using Seismic Refraction and Ground Penetrating Radar (GPR) to Characterize the Valley Fill in Beaver Meadows, Rocky Mountain National Park

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Kramer, N.; Harry, D. L.; Wohl, E. E.

2010-12-01

This study is one of the first to use near surface geophysical techniques to characterize the subsurface stratigraphy in a high alpine, low gradient valley with a past glacial history and to obtain a preliminary grasp on the impact of Holocene beaver activity. Approximately 1 km of seismic refraction data and 5 km of GPR data were collected in Beaver Meadows, Rocky Mountain National Park. An asymmetric wedge of sediment ranging in depth from 0-20 m transverse to the valley profile was identified using seismic refraction. Complementary analysis of the GPR data suggests that the valley fill can be subdivided into till deposited during the Pleistocene glaciations and alluvium deposited during the Holocene. Two main facies were identified in the GPR profiles through pattern recognition. Facie Fd, which consists of chaotic discontinuous reflectors with an abundance of diffractions, is interpreted to be glacial till. Facie Fc, which is a combination of packages of complex slightly continuous reflectors interfingered with continuous horizontal to subhorizontal reflectors, is interpreted to be post-glacial alluvium and includes overbank, pond and in-channel deposits. Fc consistently overlies Fd throughout the study area and is no more than 7 m thick in the middle of the valley. The thickness of Holocene sedimentation (beaver dams, a high abundance of fine sediment including silts and clays, historical records of beavers, and the name "Beaver Meadows" all suggest that Holocene beaver activity played a large role in sediment accumulation at this site, despite the lack of surficial relict beaver dams containing wood.

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

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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

Inflammatory changes in adipose tissue enhance expression of GPR84, a medium-chain fatty acid receptor: TNFα enhances GPR84 expression in adipocytes.

Science.gov (United States)

Nagasaki, Hiroshi; Kondo, Takaaki; Fuchigami, Masahiro; Hashimoto, Hiroyuki; Sugimura, Yoshihisa; Ozaki, Nobuaki; Arima, Hiroshi; Ota, Akira; Oiso, Yutaka; Hamada, Yoji

2012-02-17

In this study we aimed to identify the physiological roles of G protein-coupled receptor 84 (GPR84) in adipose tissue, together with medium-chain fatty acids (MCFAs), the specific ligands for GPR84. In mice, high-fat diet up-regulated GPR84 expression in fat pads. In 3T3-L1 adipocytes, co-culture with a macrophage cell line, RAW264, or TNFα remarkably enhanced GPR84 expression. In the presence of TNFα, MCFAs down-regulated adiponectin mRNA expression in 3T3-L1 adipocytes. Taken together, our results suggest that GPR84 emerges in adipocytes in response to TNFα from infiltrating macrophages and exacerbates the vicious cycle between adiposity and diabesity. Copyright © 2012 Federation of European Biochemical Societies. All rights reserved.

Test site experiments with a reconfigurable stepped frequency GPR

Science.gov (United States)

Persico, Raffaele; Matera, Loredana; Piro, Salvatore; Rizzo, Enzo; Capozzoli, Luigi

2016-04-01

second (pulsed) GPR system, radiating in the soil during the measurements. Acknowledgements The project Aitech was financed by the Puglia Region, while the Cost Action TU1208 have favoured some important avdvancements of the system thanks to the short term scitnific mission supported by it. References [1] R. Persico, G. Prisco, A Reconfigurative Approach for SF-GPR Prospecting, IEEE Trans. On Antennas and Prop., vol. 56, n.8, pp. 2673-2680, August 2008. [2] R. Persico, M. Ciminale, L. Matera, A new reconfigurable stepped frequency GPR system, possibilities and issues; applications to two different Cultural Heritage Resources, Near Surface Geophysics, vol. 12, n. 6, pp. 793-801 (doi: 10.3997/1873-0604.2014035), December 2014. [3] Capozzoli L., Caputi A., De Martino G., Giampaolo V., Luongo R., Perciante F., Rizzo E.,, Electrical and electromagnetic techniques applied to an archaeological framework reconstructed in laboratory, 8th International Workshop on Advanced Ground Penetrating Radar - IWAGPR 2015, Florence, Italy, 7-10 July, 2015. [4] Bernabini M., Pettinelli E., Pierdicca N., Piro S., Versino L., 1992. Field experiments for characterization of GPR antenna and pulse propagation. Journal of Applied Geophysics, special issue on GPR Vol.33 (1995), pp 63-76.

Targeting GPR110 in HER2-Overexpressing Breast Cancers

Science.gov (United States)

2015-10-01

34assay"using"the"transwell" inserts"with" (A)"or"without" (B)"matrigel" for"SKBR3" cells "transfected"with"nonAtarge1ng"( NT1 )"orŗ"independent"GPR110"siRNAs...HER2 drug resistant cells and in tumorigenic population using a broad panel of cell line models. We have successfully generated inducible lentiviral...plasmids with GPR110 cDNA and cell lines that inducibly overexpress GPR110. Generation of cell lines with lentiviral plasmids containing GPR110

Nondestructive measurement systems for the characterization of ancient masonry: an SLDV/GPR integrated approach

Science.gov (United States)

Agnani, Alexia; del Conte, Antonio; Esposito, Enrico; Naticchia, Berardo

2006-06-01

The determination of the state of conservation of historical masonries by non-destructive and non-invasive techniques must still gain its due widespread use, and this is clearly reflected in national norms that often refuse them as not being reliable enough to be used without the support of destructive ones (see for example the Italian OPCM 3274/2003 and subsequent modifications). Anyhow, the clear advantages of such techniques, and especially laser based ones like the Scanning Laser Doppler Vibrometry - SLDV here employed, drive the research towards this direction. In this work we will illustrate a case study done in the south of the Marche region, namely the investigations conducted inside and outside the Lanciano castle, near Castelraimondo (MC). A series of SLDV measurements have been made that have lead to the discovery of many hidden structural defects, such as delaminations of superficial layers, minor and also important cracks. To validate our findings a well reputed and consolidated technique has been employed, a Ground Penetrating Radar - GPR, along with manual beating of suspected areas. Also a brief session using an infrared camera has been conducted to check the results relative to superficial delaminations, where the GPR could fail due to insufficient spatial resolution.

Characterization of soil water content variability and soil texture using GPR groundwave techniques

Energy Technology Data Exchange (ETDEWEB)

Grote, K.; Anger, C.; Kelly, B.; Hubbard, S.; Rubin, Y.

2010-08-15

Accurate characterization of near-surface soil water content is vital for guiding agricultural management decisions and for reducing the potential negative environmental impacts of agriculture. Characterizing the near-surface soil water content can be difficult, as this parameter is often both spatially and temporally variable, and obtaining sufficient measurements to describe the heterogeneity can be prohibitively expensive. Understanding the spatial correlation of near-surface soil water content can help optimize data acquisition and improve understanding of the processes controlling soil water content at the field scale. In this study, ground penetrating radar (GPR) methods were used to characterize the spatial correlation of water content in a three acre field as a function of sampling depth, season, vegetation, and soil texture. GPR data were acquired with 450 MHz and 900 MHz antennas, and measurements of the GPR groundwave were used to estimate soil water content at four different times. Additional water content estimates were obtained using time domain reflectometry measurements, and soil texture measurements were also acquired. Variograms were calculated for each set of measurements, and comparison of these variograms showed that the horizontal spatial correlation was greater for deeper water content measurements than for shallower measurements. Precipitation and irrigation were both shown to increase the spatial variability of water content, while shallowly-rooted vegetation decreased the variability. Comparison of the variograms of water content and soil texture showed that soil texture generally had greater small-scale spatial correlation than water content, and that the variability of water content in deeper soil layers was more closely correlated to soil texture than were shallower water content measurements. Lastly, cross-variograms of soil texture and water content were calculated, and co-kriging of water content estimates and soil texture

Signal Processing of Ground Penetrating Radar Using Spectral Estimation Techniques to Estimate the Position of Buried Targets

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Shanker Man Shrestha

2003-11-01

Full Text Available Super-resolution is very important for the signal processing of GPR (ground penetration radar to resolve closely buried targets. However, it is not easy to get high resolution as GPR signals are very weak and enveloped by the noise. The MUSIC (multiple signal classification algorithm, which is well known for its super-resolution capacity, has been implemented for signal and image processing of GPR. In addition, conventional spectral estimation technique, FFT (fast Fourier transform, has also been implemented for high-precision receiving signal level. In this paper, we propose CPM (combined processing method, which combines time domain response of MUSIC algorithm and conventional IFFT (inverse fast Fourier transform to obtain a super-resolution and high-precision signal level. In order to support the proposal, detailed simulation was performed analyzing SNR (signal-to-noise ratio. Moreover, a field experiment at a research field and a laboratory experiment at the University of Electro-Communications, Tokyo, were also performed for thorough investigation and supported the proposed method. All the simulation and experimental results are presented.

Bi-Static Deep Electromagnetic Soundings for Martian Subsurface Characterization: Experimental Validation in the Egyptian Western Desert

Science.gov (United States)

Ciarletti, V.; Le Gall, A.; Berthelier, J. J.; Corbel, Ch.; Dolon, F.; Ney, R.; Reineix, A.; Guiffaud, Ch.; Clifford, S.; Heggy, E.

2007-03-01

A bi-static version of the HF GPR TAPIR developed for martian deep soundings has been operated in the Egyptian Western Desert. The study presented focuses on the retrieval of the direction of arrival of the observed echoes on both simulated and measured d

The SCFA receptor GPR43 and energy metabolism

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Ikuo eKimura

2014-06-01

Full Text Available Free fatty acids (FFAs are essential nutrients and act as signaling molecules in various cellular processes via binding with FFA receptors. Of these receptors, GPR43 is activated by short chain fatty acids (SCFAs; e.g., acetate, propionate, and butyrate. During feeding, SCFAs are produced by microbial fermentation of dietary fiber in the gut, and these SCFAs become important energy sources for the host. The gut microbiota affects nutrient acquisition and energy regulation of the host and can influence the development of obesity, insulin resistance, and diabetes. Recently, GPR43 has been reported to regulate host energy homeostasis in the gastrointestinal tract and adipose tissues. Hence, GPR43 is also thought to be a potential drug target for metabolic disorders, such as obesity and diabetes. In this review, we summarize the identification, structure, and activities of GPR43, with a focus on host energy regulation, and present an essential overview of our current understanding of its physiological roles in host energy regulation that is mediated by gut microbiota. We also discuss the potential for GPR43 as a therapeutic target.

PERFORMANCE EVALUATION OF AN AIR COUPLED PHASED ARRAY RADAR FOR NEAR FIELD DETECTION OF STEEL

Science.gov (United States)

2015-04-24

compacted, dense concrete with a good cover will be more resistant to carbonation than a porous concrete . The greatest rate of carbonation occurs when the...its design life. The health and state of the concrete roadways and bridge decks that commuters rely on a daily basis can be efficiently examined and...monitored with the use of ground penetrating radar (GPR). Repair and maintenance of these concrete structures is slow and expensive. The development

Model track studies on fouled ballast using ground penetrating radar and multichannel analysis of surface wave

Science.gov (United States)

Anbazhagan, P.; Lijun, Su; Buddhima, Indraratna; Cholachat, Rujikiatkamjorn

2011-08-01

Ballast fouling is created by the breakdown of aggregates or outside contamination by coal dust from coal trains, or from soil intrusion beneath rail track. Due to ballast fouling, the conditions of rail track can be deteriorated considerably depending on the type of fouling material and the degree of fouling. So far there is no comprehensive guideline available to identify the critical degree of fouling for different types of fouling materials. This paper presents the identification of degree of fouling and types of fouling using non-destructive testing, namely seismic surface-wave and ground penetrating radar (GPR) survey. To understand this, a model rail track with different degree of fouling has been constructed in Civil engineering laboratory, University of Wollongong, Australia. Shear wave velocity obtained from seismic survey has been employed to identify the degree of fouling and types of fouling material. It is found that shear wave velocity of fouled ballast increases initially, reaches optimum fouling point (OFP), and decreases when the fouling increases. The degree of fouling corresponding after which the shear wave velocity of fouled ballast will be smaller than that of clean ballast is called the critical fouling point (CFP). Ground penetrating radar with four different ground coupled antennas (500 MHz, 800 MHz, 1.6 GHz and 2.3 GHz) was also used to identify the ballast fouling condition. It is found that the 800 MHz ground coupled antenna gives a better signal in assessing the ballast fouling condition. Seismic survey is relatively slow when compared to GPR survey however it gives quantifiable results. In contrast, GPR survey is faster and better in estimating the depth of fouling.

Using ground penetrating radar in levee assessment to detect small scale animal burrows

Science.gov (United States)

Chlaib, Hussein K.; Mahdi, Hanan; Al-Shukri, Haydar; Su, Mehmet M.; Catakli, Aycan; Abd, Najah

2014-04-01

Levees are civil engineering structures built to protect human lives, property, and agricultural lands during flood events. To keep these important structures in a safe condition, continuous monitoring must be performed regularly and thoroughly. Small rodent burrows are one of the major defects within levees; however, their early detection and repair helps in protecting levees during flooding events. A set of laboratory experiments was conducted to analyze the polarity change in GPR signals in the presence of subsurface voids and water-filled cavities. Ground Penetrating Radar (GPR) surveys using multi frequency antennas (400 MHz and 900 MHz) were conducted along an 875 meter section of the Lollie Levee near Conway, Arkansas, USA, to assess the levee's structural integrity. Many subsurface animal burrows, water-filled cavities, clay clasts, and metallic objects were investigated and identified. These anomalies were located at different depths and have different sizes. To ground truth the observations, hand dug trenches were excavated to confirm several anomalies. Results show an excellent match between GPR interpreted anomalies and the observed features. In-situ dielectric constant measurements were used to calculate the feature depths. The results of this research show that the 900 MHz antenna has more advantages over the 400 MHz antenna.

Monsoon Convection during the South China Sea Monsoon Experiment Observed from Shipboard Radar and the TRMM Satellite

Science.gov (United States)

Rickenbach, Tom; Cifelli, Rob; Halverson, Jeff; Kucera, Paul; Atkinson, Lester; Fisher, Brad; Gerlach, John; Harris, Kathy; Kaufman, Cristina; Liu, Ching-Hwang;

Gpr161 anchoring of PKA consolidates GPCR and cAMP signaling.

Science.gov (United States)

Bachmann, Verena A; Mayrhofer, Johanna E; Ilouz, Ronit; Tschaikner, Philipp; Raffeiner, Philipp; Röck, Ruth; Courcelles, Mathieu; Apelt, Federico; Lu, Tsan-Wen; Baillie, George S; Thibault, Pierre; Aanstad, Pia; Stelzl, Ulrich; Taylor, Susan S; Stefan, Eduard

2016-07-12

Scaffolding proteins organize the information flow from activated G protein-coupled receptors (GPCRs) to intracellular effector cascades both spatially and temporally. By this means, signaling scaffolds, such as A-kinase anchoring proteins (AKAPs), compartmentalize kinase activity and ensure substrate selectivity. Using a phosphoproteomics approach we identified a physical and functional connection between protein kinase A (PKA) and Gpr161 (an orphan GPCR) signaling. We show that Gpr161 functions as a selective high-affinity AKAP for type I PKA regulatory subunits (RI). Using cell-based reporters to map protein-protein interactions, we discovered that RI binds directly and selectively to a hydrophobic protein-protein interaction interface in the cytoplasmic carboxyl-terminal tail of Gpr161. Furthermore, our data demonstrate that a binary complex between Gpr161 and RI promotes the compartmentalization of Gpr161 to the plasma membrane. Moreover, we show that Gpr161, functioning as an AKAP, recruits PKA RI to primary cilia in zebrafish embryos. We also show that Gpr161 is a target of PKA phosphorylation, and that mutation of the PKA phosphorylation site affects ciliary receptor localization. Thus, we propose that Gpr161 is itself an AKAP and that the cAMP-sensing Gpr161:PKA complex acts as cilium-compartmentalized signalosome, a concept that now needs to be considered in the analyzing, interpreting, and pharmaceutical targeting of PKA-associated functions.

Motion measurement for synthetic aperture radar

Energy Technology Data Exchange (ETDEWEB)

Doerry, Armin W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-01-01

Synthetic Aperture Radar (SAR) measures radar soundings from a set of locations typically along the flight path of a radar platform vehicle. Optimal focusing requires precise knowledge of the sounding source locations in 3-D space with respect to the target scene. Even data driven focusing techniques (i.e. autofocus) requires some degree of initial fidelity in the measurements of the motion of the radar. These requirements may be quite stringent especially for fine resolution, long ranges, and low velocities. The principal instrument for measuring motion is typically an Inertial Measurement Unit (IMU), but these instruments have inherent limi ted precision and accuracy. The question is %22How good does an IMU need to be for a SAR across its performance space?%22 This report analytically relates IMU specifications to parametric requirements for SAR. - 4 - Acknowledgements Th e preparation of this report is the result of a n unfunded research and development activity . Although this report is an independent effort, it draws heavily from limited - release documentation generated under a CRADA with General Atomics - Aeronautical System, Inc. (GA - ASI), and under the Joint DoD/DOE Munitions Program Memorandum of Understanding. Sandia National Laboratories is a multi - program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of En ergy's National Nuclear Security Administration under contract AC04-94AL85000.

Spatiotemporal Control of GPR37 Signaling and Its Behavioral Effects by Optogenetics

Directory of Open Access Journals (Sweden)

Wu Zheng

2018-03-01

Full Text Available Despite the progress in deorphanization of G Protein-Coupled Receptors (GPCRs, ≈100 GPCRs are still classified as orphan receptors without identified endogenous ligands and with unknown physiological functions. The lack of endogenous ligands triggering GPCR signaling has hampered the study of orphan GPCR functions. Using GPR37 as an example, we provide here the first demonstration of the channelrhodopsin 2 (ChR2-GPCR approach to bypass the endogenous ligand and selectively activate the orphan GPCR signal by optogenetics. Inspired by the opto-XR approach, we designed the ChR2-GPR37 chimera, in which the corresponding parts of GPR37 replaced the intracellular portions of ChR2. We showed that optogenetic activation of ChR2/opto-GPR37 elicited specific GPR37 signaling, as evidenced by reduced cAMP level, enhanced ERK phosphorylation and increased motor activity, confirming the specificity of opto-GPR37 signaling. Besides, optogenetic activation of opto-GPR37 uncovered novel aspects of GPR37 signaling (such as IP-3 signaling and anxiety-related behavior. Optogenetic activation of opto-GPR37 permits the causal analysis of GPR37 activity in the defined cells and behavioral responses of freely moving animals. Importantly, given the evolutionarily conserved seven-helix transmembrane structures of ChR2 and orphan GPCRs, we propose that opto-GPR37 approach can be readily applied to other orphan GPCRs for their deorphanization in freely moving animals.

Combining low-cost GPS receivers with upGPR to derive continuously liquid water content, snow height and snow water equivalent in Alpine snow covers

Science.gov (United States)

Koch, Franziska; Schmid, Lino; Prasch, Monika; Heilig, Achim; Eisen, Olaf; Schweizer, Jürg; Mauser, Wolfram

2015-04-01

The temporal evolution of Alpine snowpacks is important for assessing water supply, hydropower generation, flood predictions and avalanche forecasts. Especially in high mountain regions with an extremely varying topography, it is until now often difficult to derive continuous and non-destructive information on snow parameters. Since autumn 2012, we are running a new low-cost GPS (Global Positioning System) snow measurement experiment at the high alpine study site Weissfluhjoch (2450 m a.s.l.) in Switzerland. The globally and freely broadcasted GPS L1-band (1.57542 GHz) was continuously recorded with GPS antennas, which are installed at the ground surface underneath the snowpack. GPS raw data, containing carrier-to-noise power density ratio (C/N0) as well as elevation and azimuth angle information for each time step of 1 s, was stored and analyzed for all 32 GPS satellites. Since the dielectric permittivity of an overlying wet snowpack influences microwave radiation, the bulk volumetric liquid water content as well as daily melt-freeze cycles can be derived non-destructively from GPS signal strength losses and external snow height information. This liquid water content information is qualitatively in good accordance with meteorological and snow-hydrological data and quantitatively highly agrees with continuous data derived from an upward-looking ground-penetrating radar (upGPR) working in a similar frequency range. As a promising novelty, we combined the GPS signal strength data with upGPR travel-time information of active impulse radar rays to the snow surface and back from underneath the snow cover. This combination allows determining liquid water content, snow height and snow water equivalent from beneath the snow cover without using any other external information. The snow parameters derived by combining upGPR and GPS data are in good agreement with conventional sensors as e.g. laser distance gauges or snow pillows. As the GPS sensors are cheap, they can easily

Characterising pharmacological ligands to study the long chain fatty acid receptors GPR40/FFA1 and GPR120/FFA4

DEFF Research Database (Denmark)

Milligan, G; Alvarez-Curto, E; Watterson, K R

2015-01-01

The G protein-coupled receptors FFA1 (previously designated GPR40) and FFA4 (previously GPR120) are both activated by saturated and unsaturated longer-chain free fatty acids. With expression patterns and functions anticipated to directly or indirectly promote insulin secretion, provide homeostati...

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.

Geophysics and Texas History: Teachers Utilize GPS and GPR Technology to Help Restore an Abandoned Cemetery

Science.gov (United States)

Henning, A. T.; Sawyer, D. S.; Wallace, D.; Kahera, A.

2009-12-01

In July 2009, a group of twenty-six K-12 teachers investigated an abandoned cemetery in Prairie View, Texas, utilizing ground-penetrating radar (GPR) to image the subsurface and handheld global positioning system (GPS) units and a total station to record surface positions. The teachers were participants in a summer course at Rice University, ESCI 515: Geophysical Field Work for Educators. The course met for 8 full days over a two week period. During this time, the group acquired and interpreted 53 GPR profiles and over 700 GPS positions. The results of the study were presented to the Prairie View community at the end of the two weeks, and our data will be used in their effort to obtain a historical site designation for the cemetery. Wyatt Chapel Cemetery is located adjacent to the campus of Prairie View A&M University in Prairie View, TX, and is thought to have originated as a slave burial ground in the 1850’s. There are very few markers remaining, but a previous ESCI 515 course (in summer 2007) discovered multiple unmarked burials using GPR, which were confirmed by subsequent excavations. This past summer, ESCI 515 participants acquired GPR profiles in previously unexplored areas, used a total station to accurately record the positions of surface features such as headstones, and used handheld GPS units to map the location of a nearby stream bed. Participants were in-service K-12 teachers from urban Houston school districts where the majority of students are members of historically underrepresented minority groups. Recruitment efforts targeted educators who are currently teaching science without a science degree. Participants included elementary, middle and high school teachers. This summer experience is followed by a content-intensive academic year course in Physical Geology. Participants experienced the process of science first-hand and used science for community service (i.e. restoring an abandoned cemetery). Through background research, they derived a rich

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

Ground penetrating radar for fracture mapping in underground hazardous waste disposal sites: A case study from an underground research tunnel, South Korea

Science.gov (United States)

Baek, Seung-Ho; Kim, Seung-Sep; Kwon, Jang-Soon; Um, Evan Schankee

2017-06-01

Secure disposal or storage of nuclear waste within stable geologic environments hinges on the effectiveness of artificial and natural radiation barriers. Fractures in the bedrock are viewed as the most likely passage for the transport of radioactive waste away from a disposal site. We utilize ground penetrating radar (GPR) to map fractures in the tunnel walls of an underground research tunnel at the Korea Atomic Energy Research Institute (KAERI). GPR experiments within the KAERI Underground Research Tunnel (KURT) were carried out by using 200 MHz, 500 MHz, and 1000 MHz antennas. By using the high-frequency antennas, we were able to identify small-scale fractures, which were previously unidentified during the tunnel excavation process. Then, through 3-D visualization of the grid survey data, we reconstructed the spatial distribution and interconnectivity of the multi-scale fractures within the wall. We found that a multi-frequency GPR approach provided more details of the complex fracture network, including deep structures. Furthermore, temporal changes in reflection polarity between the GPR surveys enabled us to infer the hydraulic characteristics of the discrete fracture network developed behind the surveyed wall. We hypothesized that the fractures exhibiting polarity change may be due to a combination of air-filled and mineralogical boundaries. Simulated GPR scans for the considered case were consistent with the observed GPR data. If our assumption is correct, the groundwater flow into these near-surface fractures may form the water-filled fractures along the existing air-filled ones and hence cause the changes in reflection polarity over the given time interval (i.e., 7 days). Our results show that the GPR survey is an efficient tool to determine fractures at various scales. Time-lapse GPR data may be essential to characterize the hydraulic behavior of discrete fracture networks in underground disposal facilities.

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. Copyright © 2011 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Using ground-penetrating radar and sidescan sonar to compare lake bottom geology in New England

Science.gov (United States)

Nesbitt, I. M.; Campbell, S. W.; Arcone, S. A.; Smith, S. M.

2017-12-01

Post-Laurentide Ice Sheet erosion and re-deposition has had a significant influence on the geomorphology of New England. Anthropogenic activities such as forestry, farming, and construction of infrastructure such as dams and associated lake reservoirs, has further contributed to near surface changes. Unfortunately, these surface dynamics are difficult to constrain, both in space and time. One analog that can be used to estimate erosion and deposition, lake basin sedimentation, is typically derived from lake bottom sediment core samples. Reliance on core records assumes that derived sedimentation rates are representative of the broader watershed, despite being only a single point measurement. Geophysical surveys suggest that this assumption can be highly erroneous and unrepresentative of an entire lake basin. Herein, we conducted ground-penetrating radar (GPR) and side-scan sonar (SSS) surveys of multiple lakes in Maine, New Hampshire, and Vermont which are representative of different basin types to estimate sedimentation rates since Laurentide retreat. Subsequent age constraints from cores on multiple GPR-imaged horizons could be used to refine estimates of sedimentation rate change caused by evolving physical, biological, and chemical processes that control erosion, transport, and re-deposition. This presentation will provide a summary of GPR and SSS data collection methods, assumptions and limitations, structural and surficial interpretations, and key findings from multiple lake basins in New England. Results show that GPR and SSS are efficient, cost effective, and relatively accurate tools for helping to constrain lake erosion and deposition processes.

Integrated, Dual Orthogonal Antennas for Polarimetric Ground Penetrating Radar

Science.gov (United States)

Pauli, Mario; Wiesbeck, Werner

2015-04-01

Ground penetrating radar systems are mostly equipped with single polarized antennas, for example with single linear polarization or with circular polarization. The radiated waves are partly reflected at the ground surface and very often the penetrating waves are distorted in their polarization. The distortion depends on the ground homogeneity and the orientation of the antennas relative to the ground structure. The received signals from the reflecting objects may most times only be classified according to their coverage and intensity. This makes the recognition of the objects difficult or impossible. In airborne and spaceborne Remote Sensing the systems are meanwhile mostly equipped with front ends with dual orthogonal polarized antennas for a full polarimetric operation. The received signals, registered in 2x2 scattering matrices according to co- and cross polarization, are processed for the evaluation of all features of the targets. Ground penetrating radars could also profit from the scientific results of Remote Sensing. The classification of detected objects for their structure and orientation requires more information in the reflected signal than can be measured with a single polarization [1, 2]. In this paper dual linear, orthogonal polarized antennas with a common single, frequency independent phase center, are presented [3]. The relative bandwidth of these antennas can be 1:3, up to 1:4. The antenna is designed to work in the frequency range between 3 GHz and 11 GHz, but can be easily adapted to the GPR frequency range by scaling. The size of the antenna scaled for operation in typical GPR frequencies would approximately be 20 by 20 cm2. By the implementation in a dielectric carrier it could be reduced in size if required. The major problem for ultra wide band, dual polarized antennas is the frequency independent feed network, realizing the required phase shifts. For these antennas a network, which is frequency independent over a wide range, has been

Design and validation of inert homemade explosive simulants for ground penetrating radar

Science.gov (United States)

VanderGaast, Brian W.; McFee, John E.; Russell, Kevin L.; Faust, Anthony A.

2015-05-01

The Canadian Armed Forces (CAF) identified a requirement for inert simulants to act as improvised, or homemade, explosives (IEs) when training on, or evaluating, ground penetrating radar (GPR) systems commonly used in the detection of buried landmines and improvised explosive devices (IEDs). In response, Defence R and D Canada (DRDC) initiated a project to develop IE simulant formulations using commonly available inert materials. These simulants are intended to approximate the expected GPR response of common ammonium nitrate-based IEs, in particular ammonium nitrate/fuel oil (ANFO) and ammonium nitrate/aluminum (ANAl). The complex permittivity over the range of electromagnetic frequencies relevant to standard GPR systems was measured for bulk quantities of these three IEs that had been fabricated at DRDC Suffield Research Centre. Following these measurements, published literature was examined to find benign materials with both a similar complex permittivity, as well as other physical properties deemed desirable - such as low-toxicity, thermal stability, and commercial availability - in order to select candidates for subsequent simulant formulation. Suitable simulant formulations were identified for ANFO, with resulting complex permittivities measured to be within acceptable limits of target values. These IE formulations will now undergo end-user trials with CAF operators in order to confirm their utility. Investigations into ANAl simulants continues. This progress report outlines the development program, simulant design, and current validation results.

Seismic-reflection and ground penetrating radar for environmental site characterization. 1998 annual progress report

International Nuclear Information System (INIS)

Plumb, R.; Steeples, D.W.

1998-01-01

'The project''s goals are threefold: (1) to examine the complementary site-characterization capabilities of modern, three-component shallow-seismic techniques and ground-penetrating radar (GPR) methods at depths ranging from 2 to 8 m at an existing test site; (2) to demonstrate the usefulness of the two methods when used in concert to characterize, in three-dimensions, the cone of depression of a pumping well, which will serve as a proxy site for fluid-flow at an actual, polluted site; and (3) to use the site as an outdoor mesoscale laboratory to validate existing three-dimensional ground-penetrating radar and seismic-reflection computer models developed at the Univ. of Kansas. To do this, useful seismic and GPR data are being collected along the same line(s) and within the same depth range. The principal investigators selected a site in central Kansas as a primary location and, although the site itself is not environmentally sensitive, the location chosen offers particularly useful attributes for this research and will serve as a proxy site for areas that are contaminated. As part of an effort to evaluate the strengths of each method, the authors will repeat the seismic and GPR surveys on a seasonal basis to establish how the complementary information obtained varies over time. Because the water table fluctuates at this site on a seasonal basis, variations in the two types of data over time also can be observed. Such noninvasive in-situ methods of identifying and characterizing the hydrologic flow regimes at contaminated sites support the prospect of developing effective, cost-conscious cleanup strategies in the near future. As of the end of May 1998, the project is on schedule. The first field work was conducted using both of the geophysical survey methods in October of 1997, and the second field survey employed both methods in March of 1998. One of the stated tasks is to reoccupy the same survey line on a quarterly basis for two years to examine change in both

The role of the obestatin/GPR39 system in human gastric adenocarcinomas.

Science.gov (United States)

Alén, Begoña O; Leal-López, Saúl; Alén, María Otero; Viaño, Patricia; García-Castro, Victoria; Mosteiro, Carlos S; Beiras, Andrés; Casanueva, Felipe F; Gallego, Rosalía; García-Caballero, Tomás; Camiña, Jesús P; Pazos, Yolanda

2016-02-02

Obestatin, a 23-amino acid peptide encoded by the ghrelin gene, and the GPR39 receptor were reported to be involved in the control of mitogenesis of gastric cancer cell lines; however, the relationship between the obestatin/GPR39 system and gastric cancer progression remains unknown. In the present study, we determined the expression levels of the obestatin/GPR39 system in human gastric adenocarcinomas and explored their potential functional roles. Twenty-eight patients with gastric adenocarcinomas were retrospectively studied, and clinical data were obtained. The role of obestatin/GPR39 in gastric cancer progression was studied in vitro using the human gastric adenocarcinoma AGS cell line. Obestatin exogenous administration in these GPR39-bearing cells deregulated the expression of several hallmarks of the epithelial-mesenchymal transition (EMT) and angiogenesis. Moreover, obestatin signaling promoted phenotypic changes via GPR39, increasingly impacting on the cell morphology, proliferation, migration and invasion of these cells. In healthy human stomachs, obestatin expression was observed in the neuroendocrine cells and GPR39 expression was localized mainly in the chief cells of the oxyntic glands. In human gastric adenocarcinomas, no obestatin expression was found; however, an aberrant pattern of GPR39 expression was discovered, correlating to the dedifferentiation of the tumor. Altogether, our data strongly suggest the involvement of the obestatin/GPR39 system in the pathogenesis and/or clinical outcome of human gastric adenocarcinomas and highlight the potential usefulness of GPR39 as a prognostic marker in gastric cancer.

Gigantism: X-linked acrogigantism and GPR101 mutations.

Science.gov (United States)

Iacovazzo, Donato; Korbonits, Márta

X-linked acrogigantism (XLAG) is a recently identified condition of early-onset GH excess resulting from the germline or somatic duplication of the GPR101 gene on chromosome Xq26.3. Thirty patients have been formally reported so far. The disease affects mostly females, occurs usually sporadically, and is characterised by early onset and marked overgrowth. Most patients present with concomitant hyperprolactinaemia. Histopathology shows pituitary hyperplasia or pituitary adenoma with or without associated hyperplasia. XLAG-related pituitary adenomas present peculiar histopathological features that should contribute to raise the suspicion of this rare condition. Treatment is frequently challenging and multi-modal. While females present with germline mutations, the sporadic male patients reported so far were somatic mosaics with variable levels of mosaicism, although no differences in the clinical phenotype were observed between patients with germline or somatic duplication. The GPR101 gene encodes an orphan G protein-coupled receptor normally expressed in the central nervous system, and at particularly high levels in the hypothalamus. While the physiological function and the endogenous ligand of GPR101 are unknown, the high expression of GPR101 in the arcuate nucleus and the occurrence of increased circulating GHRH levels in some patients with XLAG, suggest that increased hypothalamic GHRH secretion could play a role in the pathogenesis of this condition. In this review, we summarise the published evidence on XLAG and GPR101 and discuss the results of recent studies that have investigated the potential role of GPR101 variants in the pathogenesis of pituitary adenomas. Copyright © 2016 Elsevier Ltd. All rights reserved.

Assessment of the underground construction details of a road pavement using GPR antenna systems with different frequencies

Science.gov (United States)

Alani, Amir M.; Tosti, Fabio; Bianchini Ciampoli, Luca; Benedetto, Francesco; Benedetto, Andrea

2017-04-01

The assessment of the underground construction details of a road infrastructure is a problem of great concern in highway engineering. The case becomes complicated especially when damages reoccur after carrying out remedial surface maintenance and repair works over the life cycle of the infrastructure. The challenge will be exacerbated at the presence of underground watercourses, such that the geotechnical stability of the entire road structure could be threatened. In this respect, ground-penetrating radar (GPR) has been recognised and accepted as one of the most effective non-destructive testing (NDT) techniques that could be employed in identifying the cause/s of such problems. The recent advancements and developments made in the field of GPR hardware as well as the current level of understanding of the applications and processing techniques of the GPR data have immensely added to the reliability in the utilisation of this tool in variety of subsurface investigation projects. In view of this, the work presented in here focuses on the assessment of the underground construction details of a road pavement using different frequency GPR antenna systems. In addition to this, the possible presence and location of an underground watercourse was investigated in this work. The existence of the latter problem was perceived due to reoccurrence of longitudinal and traversal road surface cracking as well as subsidence at a particular location of the road. Reoccurrence of this damage was interpreted and related to the possible existence of an underground watercourse. The original design and the construction of the road were as such to prevent this movement. Therefore it seemed necessary to perform a GPR survey to investigate and confirm the underground construction details of the road. To this purpose, the identified area was surveyed using high to low frequency antennas with 2000 MHz, 900 MHz, 600 MHz and 200 MHz central frequencies of investigation. Scans were performed at 1m

Deletion of the pH sensor GPR4 decreases renal acid excretion.

Science.gov (United States)

Sun, Xuming; Yang, Li V; Tiegs, Brian C; Arend, Lois J; McGraw, Dennis W; Penn, Raymond B; Petrovic, Snezana

2010-10-01

Proton receptors are G protein-coupled receptors that accept protons as ligands and function as pH sensors. One of the proton receptors, GPR4, is relatively abundant in the kidney, but its potential role in acid-base homeostasis is unknown. In this study, we examined the distribution of GPR4 in the kidney, its function in kidney epithelial cells, and the effects of its deletion on acid-base homeostasis. We observed GPR4 expression in the kidney cortex, in the outer and inner medulla, in isolated kidney collecting ducts, and in cultured outer and inner medullary collecting duct cells (mOMCD1 and mIMCD3). Cultured mOMCD1 cells exhibited pH-dependent accumulation of intracellular cAMP, characteristic of GPR4 activation; GPR4 knockdown attenuated this accumulation. In vivo, deletion of GPR4 decreased net acid secretion by the kidney and resulted in a nongap metabolic acidosis, indicating that GPR4 is required to maintain acid-base homeostasis. Collectively, these findings suggest that GPR4 is a pH sensor with an important role in regulating acid secretion in the kidney collecting duct.

Development of SAP-DoA techniques for GPR data processing within COST Action TU1208

Science.gov (United States)

Meschino, Simone; Pajewski, Lara; Marciniak, Marian

2016-04-01

This work focuses on the use of Sub-Array Processing (SAP) and Direction of Arrival (DoA) approaches for the processing of Ground-Penetrating Radar data, with the purpose of locating metal scatterers embedded in concrete or buried in the ground. Research activities have been carried out during two Short-Term Scientific Missions (STSMs) funded by the COST (European COoperation in Science and Technology) Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar" in May 2015 and January 2016. In applications involving smart antennas and in the presence of several transmitters operating simultaneously, it is important for a receiving array to be able to estimate the Direction of Arrival (DoA) of the incoming signals, in order to decipher how many emitters are present and predict their positions. A number of methods have been devised for DoA estimation: the MUltiple SIgnal Classification (MUSIC) and Estimation of Signal Parameters via Rotational Invariance Technique (ESPRIT) are amongst the most popular ones [1]. In the scenario considered by us, the electromagnetic sources are the currents induced on metal elements embedded in concrete or buried in the ground. GPR radargrams are processed, to estimate the DoAs of the electric field back-scattered by the sought targets. In order to work in near-field conditions, a sub-array processing (SAP) approach is adopted: the radargram is partitioned in sub-radargrams composed of few A-scans each, the dominant DoA is predicted for each sub-radargram. The estimated angles are triangulated, obtaining a set of crossings with intersections condensed around object locations. This pattern is filtered, in order to remove a noisy background of unwanted crossings, and is processed by applying the statistical procedure described in [2]. We tested our approach on synthetic GPR radargrams, obtained by using the freeware simulator gprMax implementing the Finite-Difference Time-Domain method [3]. In particular, we worked with

GPR56/ADGRG1 Inhibits Mesenchymal Differentiation and Radioresistance in Glioblastoma

Directory of Open Access Journals (Sweden)

Marta Moreno

2017-11-01

Full Text Available A mesenchymal transition occurs both during the natural evolution of glioblastoma (GBM and in response to therapy. Here, we report that the adhesion G-protein-coupled receptor, GPR56/ADGRG1, inhibits GBM mesenchymal differentiation and radioresistance. GPR56 is enriched in proneural and classical GBMs and is lost during their transition toward a mesenchymal subtype. GPR56 loss of function promotes mesenchymal differentiation and radioresistance of glioma initiating cells both in vitro and in vivo. Accordingly, a low GPR56-associated signature is prognostic of a poor outcome in GBM patients even within non-G-CIMP GBMs. Mechanistically, we reveal GPR56 as an inhibitor of the nuclear factor kappa B (NF-κB signaling pathway, thereby providing the rationale by which this receptor prevents mesenchymal differentiation and radioresistance. A pan-cancer analysis suggests that GPR56 might be an inhibitor of the mesenchymal transition across multiple tumor types beyond GBM.

Impacts of distinct observations during the 2009 Prince William Sound field experiment: A data assimilation study

Science.gov (United States)

Li, Z.; Chao, Y.; Farrara, J.; McWilliams, J. C.

2012-12-01

A set of data assimilation experiments, known as Observing System Experiments (OSEs), are performed to assess the relative impacts of different types of observations acquired during the 2009 Prince William Sound Field Experiment. The observations assimilated consist primarily of three types: High Frequency (HF) radar surface velocities, vertical profiles of temperature/salinity (T/S) measured by ships, moorings, Autonomous Underwater Vehicles and gliders, and satellite sea surface temperatures (SSTs). The impact of all the observations, HF radar surface velocities, and T/S profiles is assessed. Without data assimilation, a frequently occurring cyclonic eddy in the central Sound is overly persistent and intense. The assimilation of the HF radar velocities effectively reduces these biases and improves the representation of the velocities as well as the T/S fields in the Sound. The assimilation of the T/S profiles improves the large scale representation of the temperature/salinity and also the velocity field in the central Sound. The combination of the HF radar surface velocities and sparse T/S profiles results in an observing system capable of representing the circulation in the Sound reliably and thus producing analyses and forecasts with useful skill. It is suggested that a potentially promising observing network could be based on satellite SSHs and SSTs along with sparse T/S profiles, and future satellite SSHs with wide swath coverage and higher resolution may offer excellent data that will be of great use for predicting the circulation in the Sound.

High-Resolution Digitization of the Film Archive of SPRI/NSF/TUD Radar Sounding of the Antarctic Ice Sheet

Science.gov (United States)

Schroeder, D. M.; Dowdeswell, J. A.; Mackie, E. J.; Vega, K. I.; Emmons, J. R.; Winstein, K.; Bingham, R. G.; Benham, T. J.

2017-12-01

The airborne radio echo sounding data collected during the SPRI/NSF/TUD surveys of the Antarctic Ice Sheet in the late nineteen sixties and early seventies were recorded on a combination of 35mm and super-8 mm black-and-white optical film. These data represent the oldest extant continent-scale geophysical observations of ice thickness, internal layering and conditions beneath the Antarctic Ice Sheet. As such, when compared with modern radar sounding observations, they offer a unique opportunity to investigate temporal changes in ice sheet conditions across half a century. However, the storage of these data on film, paper-prints, and scans of those prints have made such comparison at the full radiometric and geometric resolution of the data difficult. To address this challenge, we utilized a state-of-the-art high-resolution Hollywood film scanning system to digitize the entire SPRI/NSF/TUD optical film archive. This has resulted in over two million digital images with information at the full spatial and brightness-level resolution of the original film. We present the process and results of this scanning as well as the current progress in formatting, registering, and positioning these data for release and use by the wider radio glaciological community. We also discuss the glaciological insights enabled by this effort.

Experimental Evaluation of Several Key Factors Affecting Root Biomass Estimation by 1500 MHz Ground-Penetrating Radar

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John C. Bain

2017-12-01

Full Text Available Accurate quantification of coarse roots without disturbance represents a gap in our understanding of belowground ecology. Ground penetrating radar (GPR has shown significant promise for coarse root detection and measurement, however root orientation relative to scanning transect direction, the difficulty identifying dead root mass, and the effects of root shadowing are all key factors affecting biomass estimation that require additional research. Specifically, many aspects of GPR applicability for coarse root measurement have not been tested with a full range of antenna frequencies. We tested the effects of multiple scanning directions, root crossover, and root versus soil moisture content in a sand-hill mixed oak community using a 1500 MHz antenna, which provides higher resolution than the oft used 900 MHz antenna. Combining four scanning directions produced a significant relationship between GPR signal reflectance and coarse root biomass (R2 = 0.75 (p < 0.01 and reduced variability encountered when fewer scanning directions were used. Additionally, significantly fewer roots were correctly identified when their moisture content was allowed to equalize with the surrounding soil (p < 0.01, providing evidence to support assertions that GPR cannot reliably identify dead root mass. The 1500 MHz antenna was able to identify roots in close proximity of each other as well as roots shadowed beneath shallower roots, providing higher precision than a 900 MHz antenna. As expected, using a 1500 MHz antenna eliminates some of the deficiency in precision observed in studies that utilized lower frequency antennas.

Dielectric properties estimation of the lunar regolith at CE-3 landing site using lunar penetrating radar data

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Feng, Jianqing; Su, Yan; Ding, Chunyu; Xing, Shuguo; Dai, Shun; Zou, Yongliao

2017-03-01

The second channel (CH2) of the Lunar Penetrating Radar (LPR) carried on the Chang'e-3 (CE-3) Yutu Rover was used to determine the thickness and structure of the lunar regolith. Accurately revealing the true structure beneath the surface requires knowledge of the dielectric permittivity of the regolith, which allows one to properly apply migration to the radar image. In contrast to simple assumptions in previous studies, this paper takes account of heterogeneity of the regolith and derives regolith's permittivity distribution laterally and vertically by a method widely used in data processing of terrestrial Ground Penetrating Radar (GPR). We find that regolith permittivity at the landing site increases with depth more quickly than previously recognized. At a depth of ∼2.5-3 m, the dielectric constant reaches the value of solid basalt. The radar image was migrated on the basis of the permittivity profile. We do not find any continuous distinct layers or an apparent regolith/rock interface in the migrated radargram, which implies that this area is covered by relatively young, poorly layered deposits.

Expression of the Fatty Acid Receptors GPR84 and GPR120 and Cytodifferentiation of Epithelial Cells in the Gastric Mucosa of Mouse Pups in the Course of Dietary Transition.

Science.gov (United States)

Widmayer, Patricia; Kusumakshi, Soumya; Hägele, Franziska A; Boehm, Ulrich; Breer, Heinz

2017-01-01

During weaning, the ingested food of mouse pups changes from exclusively milk to solid food. In contrast to the protein- and carbohydrate-rich solid food, high fat milk is characterized primarily by fatty acids of medium chain length particularly important for the suckling pups. Therefore, it seems conceivable that the stomach mucosa may be specialized for detecting these important nutrients during the suckling phase. Here, we analyzed the expression of the G protein coupled receptors GPR84 and GPR120 (FFAR4), which are considered to be receptors for medium and long chain fatty acids (LCFAs), respectively. We found that the mRNA levels for GPR84 and GPR120 were high during the suckling period and progressively decreased in the course of weaning. Visualization of the receptor-expressing cells in 2-week-old mice revealed a high number of labeled cells, which reside in the apical as well as in the basal region of the gastric glands. At the base of the gastric glands, all GPR84-immunoreactive cells and some of the GPR120-positive cells also expressed chromogranin A (CgA), suggesting that they are enteroendocrine cells. We demonstrate that the majority of the CgA/GPR84 cells are X/A-like ghrelin cells. The high degree of overlap between ghrelin and GPR84 decreased post-weaning, whereas the overlap between ghrelin and GPR120 increased. At the apical region of the glands the fatty acid receptors were mainly expressed in unique cell types. These contain lipid-filled vacuole- and vesicle-like structures and may have absorptive functions. We detected decreased immunoreactivity for GPR84 and no lipid droplets in surface cells post-weaning. In conclusion, expression of GPR84 in ghrelin cells as well as in surface cells suggests an important role of medium chain fatty acids (MCFAs) in the developing gastric mucosa of suckling mice.

Parabolic dune reactivation and migration at Napeague, NY, USA: Insights from aerial and GPR imagery

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Girardi, James D.; Davis, Dan M.

2010-02-01

Observations from mapping since the 19th century and aerial imagery since 1930 have been used to study changes in the aeolian geomorphology of coastal parabolic dunes over the last ~ 170 years in the Walking Dune Field, Napeague, NY. The five large parabolic dunes of the Walking Dune Field have all migrated across, or are presently interacting with, a variably forested area that has affected their migration, stabilization and morphology. This study has concentrated on a dune with a particularly complex history of stabilization, reactivation and migration. We have correlated that dune's surface evolution, as revealed by aerial imagery, with its internal structures imaged using 200 MHz and 500 MHz Ground Penetrating Radar (GPR) surveys. Both 2D (transect) and high-resolution 3D GPR imagery image downwind dipping bedding planes which can be grouped by apparent dip angle into several discrete packages of beds that reflect distinct decadal-scale episodes of dune reactivation and growth. From aerial and high resolution GPR imagery, we document a unique mode of reactivation and migration linked to upwind dune formation and parabolic dune interactions with forest trees. This study documents how dune-dune and dune-vegetation interactions have influenced a unique mode of blowout deposition that has alternated on a decadal scale between opposite sides of a parabolic dune during reactivation and migration. The pattern of recent parabolic dune reactivation and migration in the Walking Dune Field appears to be somewhat more complex, and perhaps more sensitive to subtle environmental pressures, than an idealized growth model with uniform deposition and purely on-axis migration. This pattern, believed to be prevalent among other parabolic dunes in the Walking Dune Field, may occur also in many other places where similar observational constraints are unavailable.

Extracting and identifying concrete structural defects in GPR images

Science.gov (United States)

Ye, Qiling; Jiao, Liangbao; Liu, Chuanxin; Cao, Xuehong; Huston, Dryver; Xia, Tian

2018-03-01

Traditionally most GPR data interpretations are performed manually. With the advancement of computing technologies, how to automate GPR data interpretation to achieve high efficiency and accuracy has become an active research subject. In this paper, analytical characterizations of major defects in concrete structures, including delamination, air void and moisture in GPR images, are performed. In the study, the image features of different defects are compared. Algorithms are developed for defect feature extraction and identification. For validations, both simulation results and field test data are utilized.

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

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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.

Characterization of concrete properties from dielectric properties using ground penetrating radar

International Nuclear Information System (INIS)

Lai, W.L.; Kou, S.C.; Tsang, W.F.; Poon, C.S.

2009-01-01

This paper presents the experimental results of a study of the relationships between light-weight (LWAC) and normal aggregate concrete (NAC) properties, as well as radar wave properties that are derived by using ground penetrating radar (GPR). The former (LWAC) refers to compressive strength, apparent porosity and saturated density, while the latter (NAC) refers to real part of dielectric permittivity (ε' or real permittivity) and wave energy level (E). Throughout the test period of the newly cast concrete cured for 90 days, the above mentioned material properties gradually changed which can be attributed to the effects of cement hydration, different types of aggregates and initial water to binder ratios. A number of plots describing various properties of concrete such as dielectric, strength and porosity perspectives were established. From these plots, we compare the characteristics of how much and how fast free water was turned to absorbed water in LWAC and NAC. The underlying mechanisms and a mechanistic model are then developed.

Scanning ARM Cloud Radars. Part II: Data Quality Control and Processing

Energy Technology Data Exchange (ETDEWEB)

Kollias, Pavlos; Jo, Ieng; Borque, Paloma; Tatarevic, Aleksandra; Lamer, Katia; Bharadwaj, Nitin; Widener, Kevin B.; Johnson, Karen L.; Clothiaux, Eugene E.

2014-03-01

The Scanning ARM Cloud Radars (SACR’s) are the primary instruments for documenting the four-dimensional structure and evolution of clouds within a 20-30 km radius from the ARM fixed and mobile sites. Here, the post-processing of the calibrated SACR measurements is discussed. First, a feature mask algorithm that objectively determines the presence of significant radar returns is described. The feature mask algorithm is based on the statistical properties of radar receiver noise. It accounts for atmospheric emission and is applicable even for SACR profiles with few or no signal-free range gates. Using the nearest-in-time atmospheric sounding, the SACR radar reflectivities are corrected for gaseous attenuation (water vapor and oxygen) using a line-by-line absorption model. Despite having a high pulse repetition frequency, the SACR has a narrow Nyquist velocity limit and thus Doppler velocity folding is commonly observed. An unfolding algorithm that makes use of a first guess for the true Doppler velocity using horizontal wind measurements from the nearest sounding is described. The retrieval of the horizontal wind profile from the HS-RHI SACR scan observations and/or nearest sounding is described. The retrieved horizontal wind profile can be used to adaptively configure SACR scan strategies that depend on wind direction. Several remaining challenges are discussed, including the removal of insect and second-trip echoes. The described algorithms significantly enhance SACR data quality and constitute an important step towards the utilization of SACR measurements for cloud research.

Novel Time-domain Ultra-wide Band TEM Horn Antenna for Highway GPR Applications

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Yin De

2017-12-01

Full Text Available Based on transmission line theory and impedance transition, we design an ultra-wideband Transverse ElectroMagnetic (TEM horn antenna that takes advantage of index gradient structure and loading techniques and is optimized for highway Ground Penetrating Radar (GPR applications. We use numerical simulation to analyze the effects of different curved surfaces as an extension of the antenna and further improve the antenna performance by the use of a metallic reflective cavity and distributed resistor loading. We then fabricated an antenna based on the optimization results and determined the Voltage Standing Wave Ratio (VSWR of the antenna to be less than 2 for bandwidths ranging from 0.9–12.6 GHz. The waveform fidelity of the antenna is also good and when we applied this antenna to highway scenarios, it achieved good results.

Genetic deletion of GPR52 enhances the locomotor-stimulating effect of an adenosine A2A receptor antagonist in mice: A potential role of GPR52 in the function of striatopallidal neurons.

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Nishiyama, Keiji; Suzuki, Hirobumi; Maruyama, Minoru; Yoshihara, Tomoki; Ohta, Hiroyuki

2017-09-01

G protein-coupled receptor 52 (GPR52) is largely co-expressed with dopamine D 2 receptor (DRD2) in the striatum and nucleus accumbens, and this expression pattern is similar to that of adenosine A 2A receptor (ADORA2A). GPR52 has been proposed as a therapeutic target for positive symptoms of schizophrenia, based on observations from pharmacological and transgenic mouse studies. However, the physiological role of GPR52 in dopaminergic functions in the basal ganglia remains unclear. Here, we used GPR52 knockout (KO) mice to examine the role of GPR52 in dopamine receptor-mediated and ADORA2A-mediated locomotor activity and dopamine receptor signaling. High expression of GPR52 protein in the striatum, nucleus accumbens, and lateral globus pallidus of wild type (WT) littermates was confirmed by immunohistochemical analysis. GPR52 KO and WT mice exhibited almost identical locomotor responses to the dopamine releaser methamphetamine and the N-methyl-d-aspartate antagonist MK-801. In contrast, the locomotor response to the ADORA2A antagonist istradefylline was significantly augmented in GPR52 KO mice compared to WT mice. Gene expression analysis revealed that striatal expression of DRD2, but not of dopamine D 1 receptor and ADORA2A, was significantly decreased in GPR52 KO mice. Moreover, a significant reduction in the mRNA expression of enkephalin, a marker of the activity of striatopallidal neurons, was observed in the striatum of GPR52 KO mice, suggesting that GPR52 deletion could enhance DRD2 signaling. Taken together, these results imply the physiological relevance of GPR52 in modulating the function of striatopallidal neurons, possibly by interaction of GPR52 with ADORA2A and DRD2. Copyright © 2017 Elsevier B.V. All rights reserved.

The Effect of the Different Frequency on Skin Depth of GPR Detection

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Mohammed Mejbel Salih

2017-05-01

Full Text Available Today the utilization of Ground Penetration Radar are increasing with development civil works , the requirement is increase a low cost technique, time and accuracy, all these should be founded in same time to achieve the project with fullest. In this study will use GPR instrument with three frequency(500,800,1000 MHz,and applying the experiments in various medium with different object's materials for pipe that expected founded object underground for the purpose of extract the fixed data that serve who work interest in this field. This technique will help in solve problem of underground detection ,such as water leakage in underground pipe for different depth that considered complex and expensive problem in same time in urban life .The study contribute in solve issue of utilizing the suitable frequency with penetration for detection, this is clarify through the result gotten that refer to excellent outcome.

G Protein-Coupled Receptor 87 (GPR87 Promotes Cell Proliferation in Human Bladder Cancer Cells

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Xia Zhang

2015-10-01

Full Text Available G protein-coupled receptor 87 (GPR87 is a newly deorphanized member of the cell surface molecule G protein-coupled receptor family. GPR signaling was shown to play a role in promotion of cell growth and survival, metastasis, and drug resistance. The overexpression of GPR87 has also been reported in many malignant tumors including bladder cancer. The aim of the present study is to examine the effect of silencing GPR87 expression with a replication-deficient recombinant adenoviral vector expressing short hairpin RNA targeting GPR87 (Ad-shGPR87 and to explore the underlying molecular mechanisms in bladder cancer cells. Six GPR87-expressing human bladder cancer cells, HT1197, HT1376, J82, RT112, TCCSUP and UMUC3, were used. Infection with Ad-shGPR87 effectively downregulated the GPR87 expression, and significantly reduced the percentage of viable cells in 4 of 6 cell lines as detected by an MTT assay. Significant inhibition on cell proliferation with Ad-shGPR87 was observed in the wild-type p53 bladder cancer cell lines (HT1197, RT112, TCCSUP and UMUC3, but not in the mutant p53 cells (HT1376 and J82. As represented by a wild-type p53 RT112 cell, Ad-shGPR87 infection significantly enhanced p53 and p21 expression and caused caspase-dependent apoptosis. Furthermore, the treatment with Ad-shGPR87 exerted a significant antitumor effect against the GPR87-expressing RT112 xenografts. GPR87 appeared to be a promising target for gene therapy, and Ad-shGPR87 had strong antitumor effects, specifically anti-proliferative and pro-apoptotic effects, against GPR87-expressing human bladder cancer cells.

Discovery of a potent and selective GPR120 agonist

DEFF Research Database (Denmark)

Shimpukade, Bharat; Hudson, Brian D; Hovgaard, Christine Kiel

2012-01-01

GPR120 is a receptor of unsaturated long-chain fatty acids reported to mediate GLP-1 secretion, insulin sensitization, anti-inflammatory, and anti-obesity effects and is therefore emerging as a new potential target for treatment of type 2 diabetes and metabolic diseases. Further investigation...... is however hindered by the lack of suitable receptor modulators. Screening of FFA1 ligands provided a lead with moderate activity on GPR120 and moderate selectivity over FFA1. Optimization led to the discovery of the first potent and selective GPR120 agonist....

Effects of Atmospheric Refraction on an Airborne Weather Radar Detection and Correction Method

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Lei Wang

2015-01-01

Full Text Available This study investigates the effect of atmospheric refraction, affected by temperature, atmospheric pressure, and humidity, on airborne weather radar beam paths. Using three types of typical atmospheric background sounding data, we established a simulation model for an actual transmission path and a fitted correction path of an airborne weather radar beam during airplane take-offs and landings based on initial flight parameters and X-band airborne phased-array weather radar parameters. Errors in an ideal electromagnetic beam propagation path are much greater than those of a fitted path when atmospheric refraction is not considered. The rates of change in the atmospheric refraction index differ with weather conditions and the radar detection angles differ during airplane take-off and landing. Therefore, the airborne radar detection path must be revised in real time according to the specific sounding data and flight parameters. However, an error analysis indicates that a direct linear-fitting method produces significant errors in a negatively refractive atmosphere; a piecewise-fitting method can be adopted to revise the paths according to the actual atmospheric structure. This study provides researchers and practitioners in the aeronautics and astronautics field with updated information regarding the effect of atmospheric refraction on airborne weather radar detection and correction methods.

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

Ground Penetrating Radar (GPR) is a safe, non-destructive and non-invasive imaging technique that can be effectively used for advanced inspection of composite structures and for diagnostics affecting the whole life-cycle of civil engineering works. GPR provides high resolution images of structures and subsurface through wide-band electromagnetic waves. It can be employed for the surveying of roads, pavements, bridges, tunnels, for detecting underground cavities and voids, for utility sensing, for the inspection of buildings, reinforced concrete and pre-cast concrete structures, for geotechnical investigation, in foundation design, as well as for several other purposes. Penetration and resolution of GPR depend primarily on the transmitting frequency of the equipment, the antenna characteristics, the electrical properties of the ground or of the surveyed material, and the contrasting electrical properties of the targets with respect to the surrounding medium. Generally there is a direct relationship between the transmitter frequency and the resolution that can be obtained; conversely there is an inverse relationship between frequency and penetration depth. GPR works best in dry ground environments, but can also give good results in wet, saturated materials; it does not work well in saline conditions, in high-conductivity media and through dense clays which limit signal penetration. Different approaches can be employed in the processing of collected GPR data. Once data have been processed, they still have to be analysed. This is a challenging problem, since interpretation of GPR radargrams is typically non-intuitive and considerable expertise is needed. In the presence of a complex scenario, an accurate electromagnetic forward solver is a fundamental tool for the validation of data interpretation. It can be employed for the characterization of scenarios, as a preliminary step that precedes a survey, or to gain a posteriori a better understanding of measured data. It

Orphan receptor GPR110, an oncogene overexpressed in lung and prostate cancer

International Nuclear Information System (INIS)

Lum, Amy M; Wang, Bruce B; Beck-Engeser, Gabriele B; Li, Lauri; Channa, Namitha; Wabl, Matthias

2010-01-01

GPR110 is an orphan G protein-coupled receptor--a receptor without a known ligand, a known signaling pathway, or a known function. Despite the lack of information, one can assume that orphan receptors have important biological roles. In a retroviral insertion mutagenesis screen in the mouse, we identified GPR110 as an oncogene. This prompted us to study the potential isoforms that can be gleaned from known GPR110 transcripts, and the expression of these isoforms in normal and transformed human tissues. Various epitope-tagged isoforms of GPR110 were expressed in cell lines and assayed by western blotting to determine cleavage, surface localization, and secretion patterns. GPR110 transcript and protein levels were measured in lung and prostate cancer cell lines and clinical samples, respectively, by quantitative PCR and immunohistochemistry. We found four potential splice variants of GPR110. Of these variants, we confirmed three as being expressed as proteins on the cell surface. Isoform 1 is the canonical form, with a molecular mass of about 100 kD. Isoforms 2 and 3 are truncated products of isoform 1, and are 25 and 23 kD, respectively. These truncated isoforms lack the seven-span transmembrane domain characteristic of GPR proteins and thus are not likely to be membrane anchored; indeed, isoform 2 can be secreted. Compared with the median gene expression of ~200 selected genes, GPR110 expression was low in most tissues. However, it had higher than average gene expression in normal kidney tissue and in prostate tissues originating from older donors. Although identified as an oncogene in murine T lymphomas, GPR110 is greatly overexpressed in human lung and prostate cancers. As detected by immunohistochemistry, GPR110 was overexpressed in 20 of 27 (74%) lung adenocarcinoma tissue cores and in 17 of 29 (59%) prostate adenocarcinoma tissue cores. Additionally, staining with a GPR110 antibody enabled us to differentiate between benign prostate hyperplasia and potential

Expression of the Fatty Acid Receptors GPR84 and GPR120 and Cytodifferentiation of Epithelial Cells in the Gastric Mucosa of Mouse Pups in the Course of Dietary Transition

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Patricia Widmayer

2017-08-01

Full Text Available During weaning, the ingested food of mouse pups changes from exclusively milk to solid food. In contrast to the protein- and carbohydrate-rich solid food, high fat milk is characterized primarily by fatty acids of medium chain length particularly important for the suckling pups. Therefore, it seems conceivable that the stomach mucosa may be specialized for detecting these important nutrients during the suckling phase. Here, we analyzed the expression of the G protein coupled receptors GPR84 and GPR120 (FFAR4, which are considered to be receptors for medium and long chain fatty acids (LCFAs, respectively. We found that the mRNA levels for GPR84 and GPR120 were high during the suckling period and progressively decreased in the course of weaning. Visualization of the receptor-expressing cells in 2-week-old mice revealed a high number of labeled cells, which reside in the apical as well as in the basal region of the gastric glands. At the base of the gastric glands, all GPR84-immunoreactive cells and some of the GPR120-positive cells also expressed chromogranin A (CgA, suggesting that they are enteroendocrine cells. We demonstrate that the majority of the CgA/GPR84 cells are X/A-like ghrelin cells. The high degree of overlap between ghrelin and GPR84 decreased post-weaning, whereas the overlap between ghrelin and GPR120 increased. At the apical region of the glands the fatty acid receptors were mainly expressed in unique cell types. These contain lipid-filled vacuole- and vesicle-like structures and may have absorptive functions. We detected decreased immunoreactivity for GPR84 and no lipid droplets in surface cells post-weaning. In conclusion, expression of GPR84 in ghrelin cells as well as in surface cells suggests an important role of medium chain fatty acids (MCFAs in the developing gastric mucosa of suckling mice.

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

Study of Mobile GIS Application on the Field of GPR in the Road Disease Detection

Science.gov (United States)

Liao, Q.; Yang, F.

2013-12-01

With the reflection principle of pulsed electromagnetic waves, ground penetrating radar (GPR) is available to measure depth of the pavement layer, reflecting different hidden danger underground. Currently, GPR has been widely used in road engineering with the constantly improved ability of detection and diagnosis to road diseases. The sum of road disease data of a region, a city, and even a wider range will be a very informative database, so we need a more convenient way to achieve data query intuitively. As mobile internet develops continuously, application of mobile terminal device plays a more important role in information platform. Mobile GIS, with smartphone as its terminal, is supported by the mobile Internet, GPS or base station as its positioning method. In this article, based on Android Platform and using C/S pattern, the LBS application of road diseases information which integrates Baidu Map API and database technology was discussed. After testing, it can display and query the real-time and historical road diseases data, the classification of data on a phone intuitively and easily. Because of the location technique and high portability of smart phone, the spot investigations of road diseases become easier. Though, the system needs further improvement, especially with the improving of the mobile phone performance, the system can also add the function of analysis to the disease data, thus forming a set of service system with more applicable.

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

GPR142 Controls Tryptophan-Induced Insulin and Incretin Hormone Secretion to Improve Glucose Metabolism.

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Hua V Lin

Full Text Available GPR142, a putative amino acid receptor, is expressed in pancreatic islets and the gastrointestinal tract, but the ligand affinity and physiological role of this receptor remain obscure. In this study, we show that in addition to L-Tryptophan, GPR142 signaling is also activated by L-Phenylalanine but not by other naturally occurring amino acids. Furthermore, we show that Tryptophan and a synthetic GPR142 agonist increase insulin and incretin hormones and improve glucose disposal in mice in a GPR142-dependent manner. In contrast, Phenylalanine improves in vivo glucose disposal independently of GPR142. Noteworthy, refeeding-induced elevations in insulin and glucose-dependent insulinotropic polypeptide are blunted in Gpr142 null mice. In conclusion, these findings demonstrate GPR142 is a Tryptophan receptor critically required for insulin and incretin hormone regulation and suggest GPR142 agonists may be effective therapies that leverage amino acid sensing pathways for the treatment of type 2 diabetes.

The Proton-Activated Receptor GPR4 Modulates Glucose Homeostasis by Increasing Insulin Sensitivity

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Luca Giudici

2013-11-01

Full Text Available Background: The proton-activated G protein-coupled receptor GPR4 is expressed in many tissues including white adipose tissue. GPR4 is activated by extracellular protons in the physiological pH range (i.e. pH 7.7 - 6.8 and is coupled to the production of cAMP. Methods: We examined mice lacking GPR4 and examined glucose tolerance and insulin sensitivity in young and aged mice as well as in mice fed with a high fat diet. Expression profiles of pro- and anti-inflammatory cytokines in white adipose tissue, liver and skeletal muscle was assessed. Results: Here we show that mice lacking GPR4 have an improved intraperitoneal glucose tolerance test and increased insulin sensitivity. Insulin levels were comparable but leptin levels were increased in GPR4 KO mice. Gpr4-/- showed altered expression of PPARα, IL-6, IL-10, TNFα, and TGF-1β in skeletal muscle, white adipose tissue, and liver. High fat diet abolished the differences in glucose tolerance and insulin sensitivity between Gpr4+/+ and Gpr4-/- mice. In contrast, in aged mice (12 months old, the positive effect of GPR4 deficiency on glucose tolerance and insulin sensitivity was maintained. Liver and adipose tissue showed no major differences in the mRNA expression of pro- and anti-inflammatory factors between aged mice of both genotypes. Conclusion: Thus, GPR4 deficiency improves glucose tolerance and insulin sensitivity. The effect may involve an altered balance between pro- and anti-inflammatory factors in insulin target tissues.

The Zinc Sensing Receptor, ZnR/GPR39, in Health and Disease

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Michal Hershfinkel

2018-02-01

Full Text Available A distinct G-protein coupled receptor that senses changes in extracellular Zn2+, ZnR/GPR39, was found in cells from tissues in which Zn2+ plays a physiological role. Most prominently, ZnR/GPR39 activity was described in prostate cancer, skin keratinocytes, and colon epithelial cells, where zinc is essential for cell growth, wound closure, and barrier formation. ZnR/GPR39 activity was also described in neurons that are postsynaptic to vesicular Zn2+ release. Activation of ZnR/GPR39 triggers Gαq-dependent signaling and subsequent cellular pathways associated with cell growth and survival. Furthermore, ZnR/GPR39 was shown to regulate the activity of ion transport mechanisms that are essential for the physiological function of epithelial and neuronal cells. Thus, ZnR/GPR39 provides a unique target for therapeutically modifying the actions of zinc in a specific and selective manner.

King George Island ice cap geometry updated with airborne GPR measurements

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M. Rückamp

2012-07-01

Full Text Available Ice geometry is a mandatory requirement for numerical modelling purposes. In this paper we present a consistent data set for the ice thickness, the bedrock topography and the ice surface topography of the King George Island ice cap (Arctowski icefield and the adjacent central part. The new data set is composed of ground based and airborne ground penetrating radar (GPR and differential GPS (DGPS measurements, obtained during several field campaigns. Blindow et al. (2010 already provided a comprehensive overview of the ground based measurements carried out in the safely accessible area of the ice cap. The updated data set incorporates airborne measurements in the heavily crevassed coastal areas. Therefore, in this paper special attention is paid to the airborne measurements by addressing the instrument used, survey procedure, and data processing in more detail. In particular, the inclusion of airborne GPR measurements with the 30 MHz BGR-P30-System developed at the Institute of Geophysics (University of Münster completes the picture of the ice geometry substantially. The compiled digital elevation model of the bedrock shows a rough, highly variable topography with pronounced valleys, ridges, and troughs. Mean ice thickness is 240 ± 6 m, with a maximum value of 422 ± 10 m in the surveyed area. Noticeable are bounded areas in the bedrock topography below sea level where marine based ice exists. The provided data set is required as a basis for future monitoring attempts or as input for numerical modelling experiments. The data set is available from the PANGAEA database at http://dx.doi.org/10.1594/PANGAEA.770567.

Ground-Penetrating Radar Investigations along Hajipur Fault: Himalayan Frontal Thrust—Attempt to Identify Near Subsurface Displacement, NW Himalaya, India

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Javed N. Malik

2012-01-01

Full Text Available The study area falls in the mesoseismal zone of 1905 Kangra earthquake (Mw 7.8. To identify appropriate trenching site for paleoseismic investigation and to understand the faulting geometry, ground-penetrating radar (GPR survey was conducted across a Hajipur Fault (HF2 scarp, a branching out fault of Himalayan Frontal Thrust (HFT in a foot hill zone of NW Himalaya. Several 2D and 3D profiles were collected using 200 MHz antenna with SIR 3000 unit. A 2D GPR profile collected across the HF2 scarp revealed prominent hyperbolas and discontinuous-warped reflections, suggesting a metal pipe and a zone of deformation along a low-angle thrust fault, respectively. The 3D profile revealed remarkable variation in dip of the fault plane and pattern of deformation along the strike of the fault.

Kiss-1/GPR54 protein expression in breast cancer.

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Papaoiconomou, Eleni; Lymperi, Maria; Petraki, Constantina; Philippou, Anastassios; Msaouel, Pavlos; Michalopoulou, Fani; Kafiri, Georgia; Vassilakos, George; Zografos, Georgios; Koutsilieris, Michael

2014-03-01

Numerous studies have shown that the Kiss-1 gene countervails the metastatic aptitude of several cancer cell lines and solid-tumor neoplasias. However, there still remains ambiguity regarding its role in breast cancer and literature has arisen asserting that Kiss-1 expression may be linked to an aggressive phenotype and malignant progression. Herein, we investigated the protein expression of Kiss-1 and its receptor GPR54 in breast cancer tissues compared to non-cancerous mammary tissues. Paraffin-fixed cancer tissues from 43 women with resected breast adenocarcinomas and 11 specimens derived from women suffering from fibrocystic disease, serving as controls, were immunostained with Kiss-1 and GPR54 antibodies. Kiss-1 and GPR54 protein expression levels were significantly higher in breast cancer compared to fibrocystic tissues (pbreast cancer and fibrocystic disease specimens. Kiss-1/GPR54 expression was found to be significantly higher in breast cancer compared to non-malignant mammary tissues.

Endothelial GPR124 Exaggerates the Pathogenesis of Atherosclerosis by Activating Inflammation

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Dong-Mei Gong

2018-01-01

Full Text Available Background/Aims: Endothelial cell dysfunction is the principal pathological process underlying atherosclerotic cardiovascular disease. G protein-coupled receptor 124 (GPR124, an orphan receptor in the adhesion GPCR subfamily, promotes angiogenesis in the brain. In the present study, we explored the role of endothelial GPR124 in the development and progression of atherosclerosis in adult mice. Methods: Using tetracycline-inducible transgenic systems, we generated mice expressing GPR124 specifically under control of the Tie-2 promoter. The animal model of atherosclerosis was constructed by intravenously injecting AAV-PCSK9DY into tetracycline-regulated mice and feeding the mice a high-fat diet for 16 consecutive weeks. Biochemical analysis and immunohistochemistry methods were used to address the role and mechanism of GPR124 in the pathological process of atherosclerosis. Results: Higher TC (total cholesterol and LDL-C (low density lipoprotein cholesterol levels in serum and greater lipid deposition in the aortic sinus were found in atherosclerotic mice with GPR124 overexpression, coincident with the elevated proliferation of smooth muscle cells. We observed an elevation of ONOO- in the aortic sinus in this model by using immunofluorescence, and the experiments showed that the specific overexpression of GPR124 in the endothelium induced the up-regulation of CD68, NLRP3 and caspase-1 levels in the aortic sinus. Conclusion: The above results indicate that manipulating GPR124 in the endothelium may contribute to delayed pathological progression of atherosclerosis.

Investigation of Planets and Small Bodies Using Decameter Wavelength Radar Sounders

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Safaeinili, A.

2003-12-01

Decameter wavelength radar sounders provide a unique capability for the exploration of subsurface of planets and internal structure of small bodies. Recently, a number of experimental radar sounding instruments have been proposed and/or are planned to become operational in the near future. The first of these radar sounders is MARSIS (Picardi et al.) that is about to arrive at Mars on ESA's Mars Express for a two-year mission. The second radar sounder, termed SHARAD (Seu et. al), will fly on NASA's Mars Reconnaissance orbiter in 2005. MARSIS and SHARAD have complementary science objectives in that MARSIS (0.1-5.5 MHz) is designed to explore the deep subsurface with a depth resolution of ˜100 m while SHARAD (15-25 MHz) focuses its investigation to near-surface (generation of radar sounders will benefit from high power and high data rate capability that is made available through the use of Nuclear Electric generators. An example of such high-capability mission is the Jovian Icy Moons Orbiter (JIMO) where, for example, the radar sounder can be used to explore beneath the icy surfaces of Europa in search of the ice/ocean interface. The decameter wave radar sounder is probably the only instrument that has the potential of providing an accurate estimate for the ocean depth. Another exciting and rewarding area of application for planetary radar sounding is the investigation of the deep interior of small bodies (asteroids and comets). The small size of asteroids and comets provides the opportunity to collect data in a manner that enables Radio Reflection Tomographic (RRT) reconstruction of the body in the same manner that a medical ultrasound probe can image the interior of our body. This paper provides an overview of current technical capabilities and challenges and the potential of radio sounders in the investigation of planets and small bodies.

Scanning ARM Cloud Radars Part II. Data Quality Control and Processing