WorldWideScience

Sample records for base em radar

  1. Plasma-based radar cross section reduction

    CERN Document Server

    Singh, Hema; Jha, Rakesh Mohan

    2016-01-01

    This book presents a comprehensive review of plasma-based stealth, covering the basics, methods, parametric analysis, and challenges towards the realization of the idea. The concealment of aircraft from radar sources, or stealth, is achieved through shaping, radar absorbing coatings, engineered materials, or plasma, etc. Plasma-based stealth is a radar cross section (RCS) reduction technique associated with the reflection and absorption of incident electromagnetic (EM) waves by the plasma layer surrounding the structure. A plasma cloud covering the aircraft may give rise to other signatures such as thermal, acoustic, infrared, or visual. Thus it is a matter of concern that the RCS reduction by plasma enhances its detectability due to other signatures. This needs a careful approach towards the plasma generation and its EM wave interaction. The book starts with the basics of EM wave interactions with plasma, briefly discuss the methods used to analyze the propagation characteristics of plasma, and its generatio...

  2. A spectral domain approach to modelling of EM scattering for Synthetic Aperture Radar target recognition

    Science.gov (United States)

    Sabry, R.; Vachon, P. W.

    2005-08-01

    A Fourier-based technique for electromagnetic (EM) wave reconstruction with application to polarimetric airborne and spaceborne radar data exploitation is presented. The method is different from conventional modelling techniques for Synthetic Aperture Radar (SAR) applications as a result of the full electromagnetic treatment of field interactions with the scatterer, the possibility of introducing new and controllable feature classes for target classification, and accurate decomposition of the source impulse response function that avoids potential errors (e.g. loss of coherent information) associated with the spherical phase approximations. The capability of extracting scatterer information such as the coherent radar cross section (RCS) is explored.

  3. MST radar data-base management

    Science.gov (United States)

    Wickwar, V. B.

    1983-01-01

    Data management for Mesospheric-Stratospheric-Tropospheric, (MST) radars is addressed. An incoherent-scatter radar data base is discussed in terms of purpose, centralization, scope, and nature of the data base management system.

  4. Radar based autonomous sensor module

    Science.gov (United States)

    Styles, Tim

    2016-10-01

    Most surveillance systems combine camera sensors with other detection sensors that trigger an alert to a human operator when an object is detected. The detection sensors typically require careful installation and configuration for each application and there is a significant burden on the operator to react to each alert by viewing camera video feeds. A demonstration system known as Sensing for Asset Protection with Integrated Electronic Networked Technology (SAPIENT) has been developed to address these issues using Autonomous Sensor Modules (ASM) and a central High Level Decision Making Module (HLDMM) that can fuse the detections from multiple sensors. This paper describes the 24 GHz radar based ASM, which provides an all-weather, low power and license exempt solution to the problem of wide area surveillance. The radar module autonomously configures itself in response to tasks provided by the HLDMM, steering the transmit beam and setting range resolution and power levels for optimum performance. The results show the detection and classification performance for pedestrians and vehicles in an area of interest, which can be modified by the HLDMM without physical adjustment. The module uses range-Doppler processing for reliable detection of moving objects and combines Radar Cross Section and micro-Doppler characteristics for object classification. Objects are classified as pedestrian or vehicle, with vehicle sub classes based on size. Detections are reported only if the object is detected in a task coverage area and it is classified as an object of interest. The system was shown in a perimeter protection scenario using multiple radar ASMs, laser scanners, thermal cameras and visible band cameras. This combination of sensors enabled the HLDMM to generate reliable alerts with improved discrimination of objects and behaviours of interest.

  5. Model-Based Radar Power Calculations for Ultra-Wideband (UWB) Synthetic Aperture Radar (SAR)

    Science.gov (United States)

    2013-06-01

    performance in complex scenarios. Among these scenarios are ground penetrating radar and forward-looking radar for landmine and improvised explosive...Model-Based Radar Power Calculations for Ultra-Wideband (UWB) Synthetic Aperture Radar (SAR) by Traian Dogaru ARL-TN-0548 June 2013...2013 Model-Based Radar Power Calculations for Ultra-Wideband (UWB) Synthetic Aperture Radar (SAR) Traian Dogaru Sensors and Electron

  6. EM wave propagation analysis in plasma covered radar absorbing material

    CERN Document Server

    Singh, Hema; Rawat, Harish Singh

    2017-01-01

    This book focuses on EM propagation characteristics within multilayered plasma-dielectric-metallic media. The method used for analysis is impedance transformation method. Plasma covered radar absorbing material is approximated as a multi-layered dielectric medium. The plasma is considered to be bounded homogeneous/inhomogeneous medium. The reflection coefficient and hence return loss is analytically derived. The role of plasma parameters, such as electron density, collision frequency, plasma thickness, and plasma density profile in the absorption behavior of multi-layered plasma-RAM structure is described. This book provides a clearer picture of EM propagation within plasma. The reader will get an insight of plasma parameters that play significant role in deciding the absorption characteristics of plasma covered surfaces.

  7. Knowledge Based Systems and Metacognition in Radar

    Science.gov (United States)

    Capraro, Gerard T.; Wicks, Michael C.

    An airborne ground looking radar sensor's performance may be enhanced by selecting algorithms adaptively as the environment changes. A short description of an airborne intelligent radar system (AIRS) is presented with a description of the knowledge based filter and detection portions. A second level of artificial intelligence (AI) processing is presented that monitors, tests, and learns how to improve and control the first level. This approach is based upon metacognition, a way forward for developing knowledge based systems.

  8. Probabilistic forecasts based on radar rainfall uncertainty

    Science.gov (United States)

    Liguori, S.; Rico-Ramirez, M. A.

    2012-04-01

    The potential advantages resulting from integrating weather radar rainfall estimates in hydro-meteorological forecasting systems is limited by the inherent uncertainty affecting radar rainfall measurements, which is due to various sources of error [1-3]. The improvement of quality control and correction techniques is recognized to play a role for the future improvement of radar-based flow predictions. However, the knowledge of the uncertainty affecting radar rainfall data can also be effectively used to build a hydro-meteorological forecasting system in a probabilistic framework. This work discusses the results of the implementation of a novel probabilistic forecasting system developed to improve ensemble predictions over a small urban area located in the North of England. An ensemble of radar rainfall fields can be determined as the sum of a deterministic component and a perturbation field, the latter being informed by the knowledge of the spatial-temporal characteristics of the radar error assessed with reference to rain-gauges measurements. This approach is similar to the REAL system [4] developed for use in the Southern-Alps. The radar uncertainty estimate can then be propagated with a nowcasting model, used to extrapolate an ensemble of radar rainfall forecasts, which can ultimately drive hydrological ensemble predictions. A radar ensemble generator has been calibrated using radar rainfall data made available from the UK Met Office after applying post-processing and corrections algorithms [5-6]. One hour rainfall accumulations from 235 rain gauges recorded for the year 2007 have provided the reference to determine the radar error. Statistics describing the spatial characteristics of the error (i.e. mean and covariance) have been computed off-line at gauges location, along with the parameters describing the error temporal correlation. A system has then been set up to impose the space-time error properties to stochastic perturbations, generated in real-time at

  9. Validation of GPM Ka-Radar Algorithm Using a Ground-based Ka-Radar System

    Science.gov (United States)

    Nakamura, Kenji; Kaneko, Yuki; Nakagawa, Katsuhiro; Furukawa, Kinji; Suzuki, Kenji

    2016-04-01

    GPM led by the Japan Aerospace Exploration Agency (JAXA) and the National Aeronautics and Space Administration of US (NASA) aims to observe global precipitation. The core satellite is equipped with a microwave radiometer (GMI) and a dual-frequency radar (DPR) which is the first spaceborne Ku/Ka-band dual-wavelength radar dedicated for precipitation measurement. In the DPR algorithm, measured radar reflectivity is converted to effective radar reflectivity by estimating the rain attenuation. Here, the scattering/attenuation characteristics of Ka-band radiowaves are crucial, particularly for wet snow. A melting layer observation using a dual Ka-band radar system developed by JAXA was conducted along the slope of Mt. Zao in Yamagata Prefecture, Japan. The dual Ka-band radar system consists of two nearly identical Ka-band FM-CW radars, and the precipitation systems between two radars were observed in opposite directions. From this experiment, equivalent radar reflectivity (Ze) and specific attenuation (k) were obtained. The experiments were conducted for two winter seasons. During the data analyses, it was found that k estimate easily fluctuates because the estimate is based on double difference calculation. With much temporal and spatial averaging, k-Ze relationship was obtained for melting layers. One of the results is that the height of the peak of k seems slightly higher than that of Ze. The results are compared with in-situ precipitation particle measurements.

  10. Comparison of Precipitation Observations from a Prototype Space-based Cloud Radar and Ground-based Radars

    Institute of Scientific and Technical Information of China (English)

    LIU Liping; ZHANG Zhiqiang; YU Danru; YANG Hu; ZHAO Chonghui; ZHONG Lingzhi

    2012-01-01

    A prototype space-based cloud radar has been developed and was installed on an airplane to observe a precipitation system over Tianjin,China in July 2010.Ground-based S-band and Ka-band radars were used to examine the observational capability of the prototype. A cross-comparison algorithm between different wavelengths,spatial resolutions and platform radars is presented.The reflectivity biases,correlation coefficients and standard deviations between the radars are analyzed.The equivalent reflectivity bias between the S- and Ka-band radars were simulated with a given raindrop size distribution.The results indicated that reflectivity bias between the S- and Ka-band radars due to scattering properties was less than 5 dB,and for weak precipitation the bias was negligible. The prototype space-based cloud radar was able to measure a reasonable vertical profile of reflectivity,but the reflectivity below an altitude of 1.5 km above ground level was obscured by ground clutter.The measured reflectivity by the prototype space-based cloud radar was approximately 10.9 dB stronger than that by the S-band Doppler radar (SA radar),and 13.7 dB stronger than that by the ground-based cloud radar.The reflectivity measured by the SA radar was 0.4 dB stronger than that by the ground-based cloud radar.This study could provide a method for the quantitative examination of the observation ability for space-based radars.

  11. Preface: Recent progress from networked studies based around MST radar

    Science.gov (United States)

    Hocking, Wayne K.; Lehmann, Volker; Singer, Werner; Yamamoto, Masayuki

    2014-10-01

    Studies of the mesosphere, stratosphere, and troposphere by radar, application of networks, and multi-instrument studies have grown significantly in recent years, and have covered a wide range of areas in technology, fundamental research, and application. This special issue of the Journal of Atmospheric and Solar-Terrestrial Physics on "Recent progress from networked studies based around MST radar" focuses primarily on selected papers presented at the 13th International Workshops on Scientific and Technical Aspects of MST Radar (MST13).

  12. Wavelet based hierarchical coding scheme for radar image compression

    Science.gov (United States)

    Sheng, Wen; Jiao, Xiaoli; He, Jifeng

    2007-12-01

    This paper presents a wavelet based hierarchical coding scheme for radar image compression. Radar signal is firstly quantized to digital signal, and reorganized as raster-scanned image according to radar's repeated period frequency. After reorganization, the reformed image is decomposed to image blocks with different frequency band by 2-D wavelet transformation, each block is quantized and coded by the Huffman coding scheme. A demonstrating system is developed, showing that under the requirement of real time processing, the compression ratio can be very high, while with no significant loss of target signal in restored radar image.

  13. Assimilation of radar-based nowcast into HIRLAM NWP model

    DEFF Research Database (Denmark)

    Jensen, David Getreuer; Petersen, Claus; Rasmussen, Michael R.

    2015-01-01

    The present study introduces a nowcast scheme that assimilates radar extrapolation data (RED) into a nowcasting version of the high resolution limited area model (HIRLAM) numerical weather prediction (NWP) model covering the area of Denmark. The RED are based on the Co-TREC (tracking radar echoes...... by correlation) methodology and are generated from cleaned radar mosaics from the Danish weather radar network. The assimilation technique is a newly developed method that increases model precipitation by increasing low-level convergence and decreasing convergence aloft in order to increase the vertical velocity...

  14. Radar Target Classification using Recursive Knowledge-Based Methods

    DEFF Research Database (Denmark)

    Jochumsen, Lars Wurtz

    The topic of this thesis is target classification of radar tracks from a 2D mechanically scanning coastal surveillance radar. The measurements provided by the radar are position data and therefore the classification is mainly based on kinematic data, which is deduced from the position. The target...... been terminated. Therefore, an update of the classification results must be made for each measurement of the target. The data for this work are collected throughout the PhD and are both collected from radars and other sensors such as GPS....

  15. Detecting weather radar clutter using satellite-based nowcasting products

    DEFF Research Database (Denmark)

    Jensen, Thomas B.S.; Gill, Rashpal S.; Overgaard, Søren

    2006-01-01

    This contribution presents the initial results from experiments with detection of weather radar clutter by information fusion with satellite based nowcasting products. Previous studies using information fusion of weather radar data and first generation Meteosat imagery have shown promising results...... for the detecting and removal of clutter. Naturally, the improved spatio-temporal resolution of the Meteosat Second Generation sensors, coupled with its increased number of spectral bands, is expected to yield even better detection accuracies. Weather radar data from three C-band Doppler weather radars...... for three rain intensity classes (heavy precipitation, light to moderate precipitation, and no precipitation) to every pixel in the Meteosat-8 images. Image fusion of the satellite image product and the radar composite images was done by resampling to a common grid of a spatial resolution dictated...

  16. Basic gait analysis based on continuous wave radar.

    Science.gov (United States)

    Zhang, Jun

    2012-09-01

    A gait analysis method based on continuous wave (CW) radar is proposed in this paper. Time-frequency analysis is used to analyze the radar micro-Doppler echo from walking humans, and the relationships between the time-frequency spectrogram and human biological gait are discussed. The methods for extracting the gait parameters from the spectrogram are studied in depth and experiments on more than twenty subjects have been performed to acquire the radar gait data. The gait parameters are calculated and compared. The gait difference between men and women are presented based on the experimental data and extracted features. Gait analysis based on CW radar will provide a new method for clinical diagnosis and therapy.

  17. Radar Scan Strategies for the Patrick Air Force Base Weather Surveillance Radar, Model-74C, Replacement

    Science.gov (United States)

    Short, David

    2008-01-01

    The 45th Weather Squadron (45 WS) is replacing the Weather Surveillance Radar, Model 74C (WSR-74C) at Patrick Air Force Base (PAFB), with a Doppler, dual polarization radar, the Radtec 43/250. A new scan strategy is needed for the Radtec 43/250, to provide high vertical resolution data over the Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) launch pads, while taking advantage of the new radar's advanced capabilities for detecting severe weather phenomena associated with convection within the 45 WS area of responsibility. The Applied Meteorology Unit (AMU) developed several scan strategies customized for the operational needs of the 45 WS. The AMU also developed a plan for evaluating the scan strategies in the period prior to operational acceptance, currently scheduled for November 2008.

  18. Security information factor based airborne radar RF stealth

    Institute of Scientific and Technical Information of China (English)

    Fei Wang; Mathini Sellathurai; Weigang Liu; Jiangjiang Zhou

    2015-01-01

    Radar radio frequency (RF) stealth is very important in electronic war (EW), and waveform design and selection. Existing evaluation rules of radar RF stealth include too many parameters of radar and interceptors, such as Schleher interception factor, which makes it difficult to evaluate radar RF stealth technologies if interceptor parameters are unknown. In communication, security capacity has been presented to describe the possible ability to communicate in complete security. Since the essential of the secu-rity capacity is to have the interceptor get none valued information from the emitter, this paper is proposed to study security infor-mation factors taking advantage of mutual information to evaluate radar RF stealth under some conditions. Through analyzing mutual information obtained by the radar and the interceptor, this paper defines the security information factor with and without cooperative jamming. Furthermore, this paper deduces the ratio of the match filter to the match incoherent filter and discuss mutual information received by the interceptor. Numerical simulations il ustrate radar RF stealth effects based on the security information factor concept under different conditions.

  19. Radar-based remote sensing monitoring of roads

    OpenAIRE

    Crosetto, Michele; Monserrat, Oriol; Luzi, Guido; Cuevas-González, María; Devanthéry, Núria

    2014-01-01

    This paper provides a brief description of two powerful radar-based remote sensing techniques to monitor the deformations of roads, their associated infrastructures and, more in general, their surroundings. The first technique is the satellite radar interferometric technique. In this work a specific technique, named Persistent Scatterer Interferometry (PSI), is considered. This technique has wide-area coverage capability (e.g. covering thousands of square kilometres at the time) and,at the...

  20. Compressive spectrum sensing of radar pulses based on photonic techniques.

    Science.gov (United States)

    Guo, Qiang; Liang, Yunhua; Chen, Minghua; Chen, Hongwei; Xie, Shizhong

    2015-02-23

    We present a photonic-assisted compressive sampling (CS) system which can acquire about 10(6) radar pulses per second spanning from 500 MHz to 5 GHz with a 520-MHz analog-to-digital converter (ADC). A rectangular pulse, a linear frequency modulated (LFM) pulse and a pulse stream is respectively reconstructed faithfully through this system with a sliding window-based recovery algorithm, demonstrating the feasibility of the proposed photonic-assisted CS system in spectral estimation for radar pulses.

  1. UWB radar target recognition based on time-domain bispectrum

    Institute of Scientific and Technical Information of China (English)

    Liu Donghong; Zhang Yongshun; Chen Zhijie; Cheng Junbin

    2006-01-01

    Complex targets are irradiated by UWB radar, not only the mirror scattering echoes but also the multiscattering interacting echoes are included in target echoes. These two echoes can not be distinguished by classical frequency spectrum and power spectrum. Time-domain bispectrum features of UWB radar signals that mingled with noise are analyzed, then processing this kind of signal using the method of time-domain bispectrum is experimented. At last, some UWB radar returns with different signal noise ratio are simulated using the method of time-domain bispectrum. Theoretical analysis and the results of simulation show that the method of extraction partial features of UWB radar targets based on time-domain bispectrum is good, and target classification and recognition can be implemented using those features.

  2. Improved Minimum Detectable Velocity in Bistatic Space-Based Radar

    Institute of Scientific and Technical Information of China (English)

    LI Hua; TANG Jun; PENG Yingning

    2008-01-01

    Single orbit bistatic space-based radar (SBR) is composed of two radars in the same orbit. The characteristics of the clutter Doppler-angle spectrum of a single orbit bistatic SBR show that the slope of the mainbeam clutter spectrum is highly sensitive to the cone angles. Therefore, the minimum detectable veloc-ity of the bistatic system is dependent on the cone angle. Then a new combined working mode of single-orbit bistatic SBR system was developed in which one radar will act as the transmitter and another as the receiver to improve detection performance for all angles. Simulation results by space-time adaptive process-ing verify the improved detection performance. The new design also reduces the average power of each ra-dar system and the size and weight of the on-board solar array-battery system.

  3. NOVEL RADAR SIGNAL SORTING METHOD BASED ON GEOMETRIC COVERING

    Institute of Scientific and Technical Information of China (English)

    万建; 国强; 宋文明

    2013-01-01

    With the increase of complexity of electromagnetic environment and continuous appearance of advanced system radars ,signals received by radar reconnaissance receivers become even more intensive and complex .There-fore ,traditional radar sorting methods based on neural network algorithms and support vector machine (SVM ) cannot process them effectively .Aiming at solving this problem ,a novel radar signal sorting method based on the cloud model theory and the geometric covering algorithm is proposed .By applying the geometric covering algo-rithm to divide input signals into different covering domains based on their distribution characteristics ,the method can overcome a typical problem that it is easy for traditional sorting algorithms to fall into the local extrema due to the use of complex nonlinear equation to describe input signals .The method uses the cloud model to describe the membership degree between signals to be sorted and their covering domains ,thus it avoids the disadvantage that traditional sorting methods based on hard clustering cannot deinterleave the signal samples with overlapped param-eters .Experimental results show that the presented method can effectively sort advanced system radar signals with overlapped parameters in complex electromagnetic environment .

  4. CSSF MIMO RADAR: Low-Complexity Compressive Sensing Based MIMO Radar That Uses Step Frequency

    CERN Document Server

    Yu, Yao; Poor, H Vincent

    2011-01-01

    A new approach is proposed, namely CSSF MIMO radar, which applies the technique of step frequency (SF) to compressive sensing (CS) based multi-input multi-output (MIMO) radar. The proposed approach enables high resolution range, angle and Doppler estimation, while transmitting narrowband pulses. The problem of joint angle-Doppler-range estimation is first formulated to fit the CS framework, i.e., as an L1 optimization problem. Direct solution of this problem entails high complexity as it employs a basis matrix whose construction requires discretization of the angle-Doppler-range space. Since high resolution requires fine space discretization, the complexity of joint range, angle and Doppler estimation can be prohibitively high. For the case of slowly moving targets, a technique is proposed that achieves significant complexity reduction by successively estimating angle-range and Doppler in a decoupled fashion and by employing initial estimates obtained via matched filtering to further reduce the space that nee...

  5. Relationship between Cloud Characteristics and Radar Reflectivity Based on Aircraft and Cloud Radar Co-observations

    Institute of Scientific and Technical Information of China (English)

    ZONG Rong; LIU Liping; YIN Yan

    2013-01-01

    Cloud properties were investigated based on aircraft and cloud radar co-observation conducted at Yitong,Jilin,Northeast China.The aircraft provided in situ measurements of cloud droplet size distribution,while the millimeter-wavelength cloud radar vertically scanned the same cloud that the aircraft penetrated.The reflectivity factor calculated from aircraft measurements was compared in detail with simultaneous radar observations.The results showed that the two reflectivities were comparable in warm clouds,but in ice cloud there were more differences,which were probably associated with the occurrence of liquid water.The acceptable agreement between reflectivities obtained in water cloud confirmed that it is feasible to derive cloud properties by using aircraft data,and hence for cloud radar to remotely sense cloud properties.Based on the dataset collected in warm clouds,the threshold of reflectivity to diagnose drizzle and cloud particles was studied by analyses of the probability distribution function of reflectivity from cloud particles and drizzle drops.The relationship between reflectivity factor (Z) and cloud liquid water content (LWC) was also derived from data on both cloud particles and drizzle.In comparison with cloud droplets,the relationship for drizzle was blurred by many scatter points and thus was less evident.However,these scatters could be partly removed by filtering out the drop size distribution with a large ratio of reflectivity and large extinction coefficient but small effective radius.Empirical relationships of Z-LWC for both cloud particles and drizzle could then be derived.

  6. Multi-function radar emitter identification based on stochastic syntax-directed translation schema

    Institute of Scientific and Technical Information of China (English)

    Liu Haijun Diao; Yu Hongqi; Sun Zhaolin; Jietao

    2014-01-01

    To cope with the problem of emitter identification caused by the radar words’ uncer-tainty of measured multi-function radar emitters, this paper proposes a new identification method based on stochastic syntax-directed translation schema (SSDTS). This method, which is deduced from the syntactic modeling of multi-function radars, considers the probabilities of radar phrases appearance in different radar modes as well as the probabilities of radar word errors occurrence in different radar phrases. It concludes that the proposed method can not only correct the defective radar words by using the stochastic translation schema, but also identify the real radar phrases and working modes of measured emitters concurrently. Furthermore, a number of simulations are presented to demonstrate the identification capability and adaptability of the SSDTS algorithm. The results show that even under the condition of the defective radar words distorted by noise, the proposed algorithm can infer the phrases, work modes and types of measured emitters correctly.

  7. Fiber-based swept-source terahertz radar.

    Science.gov (United States)

    Huang, Yu-Wei; Tseng, Tzu-Fang; Kuo, Chung-Chiu; Hwang, Yuh-Jing; Sun, Chi-Kuang

    2010-05-01

    We demonstrate an all-terahertz swept-source imaging radar operated at room temperature by using terahertz fibers for radiation delivery and with a terahertz-fiber directional coupler acting as a Michelson interferometer. By taking advantage of the high water reflection contrast in the low terahertz regime and by electrically sweeping at a high speed a terahertz source combined with a fast rotating mirror, we obtained the living object's distance information with a high image frame rate. Our experiment showed that this fiber-based swept-source terahertz radar could be used in real time to locate concealed moving live objects with high stability.

  8. Radar Based Flow and Water Level Forecasting in Sewer Systems

    DEFF Research Database (Denmark)

    Thorndahl, Søren; Rasmussen, Michael R.; Grum, M.

    2009-01-01

    This paper describes the first radar based forecast of flow and/or water level in sewer systems in Denmark. The rainfall is successfully forecasted with a lead time of 1-2 hours, and flow/levels are forecasted an additional ½-1½ hours using models describing the behaviour of the sewer system. Both...... radar data and flow/water level model are continuously updated using online rain gauges and online in-sewer measurements, in order to make the best possible predictions. The project show very promising results, and show large potentials, exploiting the existing water infrastructure in future climate...

  9. Radar Image Texture Classification based on Gabor Filter Bank

    OpenAIRE

    Mbainaibeye Jérôme; Olfa Marrakchi Charfi

    2014-01-01

    The aim of this paper is to design and develop a filter bank for the detection and classification of radar image texture with 4.6m resolution obtained by airborne synthetic Aperture Radar. The textures of this kind of images are more correlated and contain forms with random disposition. The design and the developing of the filter bank is based on Gabor filter. We have elaborated a set of filters applied to each set of feature texture allowing its identification and enhancement in comparison w...

  10. Design of a Radar Based Space Situational Awareness System

    Science.gov (United States)

    Liebschwager, T.; Neff, T.; Suess, I. H.; Foerstner, I. R.

    2013-09-01

    Existing SSA-Networks in most cases consist of sensors which originally were not designed for the purpose of detecting or tracking space debris and active satellites. Furthermore there are different kinds of sensors in use which makes it even more complicated to handle all generated data. Therefore it is reasonable to create a network consisting of homogenous sensors, which means sensors of the same type (like radar or optical) and with the same output format of the data. Technologies that are available for detection and tracking of objects (e.g. optical sensors or radar) will be discussed. Focal point will be on operational availability, reliability and obtainable accuracy. It will be shown that Phased Array Radars are the most reasonable technology to be used while creating a sensor network consisting of homogenous sensors. This paper entails to present a proposal for a network of Phased Array Radars configured for this purpose. The system is intended to detect and track objects that are at least as small as objects that can currently be found in the US SSN catalogue. Furthermore potential hazards in different orbits will be evaluated and discussed to optimize the system on these areas. The system is supposed to be able to create an own object catalogue. Therefore perseverative tracking and required capacity will also be considered. On the basis of these considerations the paper shows how to lay-up such a radar-system starting from scratch. Criteria for detection and tracking of objects will be determined. This part of the work contains aspects like choosing the frequency band or tracking-frequencies for different sizes of objects. In the next step the locations for the sensors will be chosen. Based on thoughts about infrastructure it is plausible to place the radar systems on existing observation sites. By analyzing simulations with different numbers of sensors and / or locations several feasible approaches for such a Space Situational Awareness Network will be

  11. LPI Radar Waveform Recognition Based on Time-Frequency Distribution.

    Science.gov (United States)

    Zhang, Ming; Liu, Lutao; Diao, Ming

    2016-10-12

    In this paper, an automatic radar waveform recognition system in a high noise environment is proposed. Signal waveform recognition techniques are widely applied in the field of cognitive radio, spectrum management and radar applications, etc. We devise a system to classify the modulating signals widely used in low probability of intercept (LPI) radar detection systems. The radar signals are divided into eight types of classifications, including linear frequency modulation (LFM), BPSK (Barker code modulation), Costas codes and polyphase codes (comprising Frank, P1, P2, P3 and P4). The classifier is Elman neural network (ENN), and it is a supervised classification based on features extracted from the system. Through the techniques of image filtering, image opening operation, skeleton extraction, principal component analysis (PCA), image binarization algorithm and Pseudo-Zernike moments, etc., the features are extracted from the Choi-Williams time-frequency distribution (CWD) image of the received data. In order to reduce the redundant features and simplify calculation, the features selection algorithm based on mutual information between classes and features vectors are applied. The superiority of the proposed classification system is demonstrated by the simulations and analysis. Simulation results show that the overall ratio of successful recognition (RSR) is 94.7% at signal-to-noise ratio (SNR) of -2 dB.

  12. LPI Radar Waveform Recognition Based on Time-Frequency Distribution

    Directory of Open Access Journals (Sweden)

    Ming Zhang

    2016-10-01

    Full Text Available In this paper, an automatic radar waveform recognition system in a high noise environment is proposed. Signal waveform recognition techniques are widely applied in the field of cognitive radio, spectrum management and radar applications, etc. We devise a system to classify the modulating signals widely used in low probability of intercept (LPI radar detection systems. The radar signals are divided into eight types of classifications, including linear frequency modulation (LFM, BPSK (Barker code modulation, Costas codes and polyphase codes (comprising Frank, P1, P2, P3 and P4. The classifier is Elman neural network (ENN, and it is a supervised classification based on features extracted from the system. Through the techniques of image filtering, image opening operation, skeleton extraction, principal component analysis (PCA, image binarization algorithm and Pseudo–Zernike moments, etc., the features are extracted from the Choi–Williams time-frequency distribution (CWD image of the received data. In order to reduce the redundant features and simplify calculation, the features selection algorithm based on mutual information between classes and features vectors are applied. The superiority of the proposed classification system is demonstrated by the simulations and analysis. Simulation results show that the overall ratio of successful recognition (RSR is 94.7% at signal-to-noise ratio (SNR of −2 dB.

  13. Radar Image Texture Classification based on Gabor Filter Bank

    Directory of Open Access Journals (Sweden)

    Mbainaibeye Jérôme

    2014-01-01

    Full Text Available The aim of this paper is to design and develop a filter bank for the detection and classification of radar image texture with 4.6m resolution obtained by airborne synthetic Aperture Radar. The textures of this kind of images are more correlated and contain forms with random disposition. The design and the developing of the filter bank is based on Gabor filter. We have elaborated a set of filters applied to each set of feature texture allowing its identification and enhancement in comparison with other textures. The filter bank which we have elaborated is represented by a combination of different texture filters. After processing, the selected filter bank is the filter bank which allows the identification of all the textures of an image with a significant identification rate. This developed filter is applied to radar image and the obtained results are compared with those obtained by using filter banks issue from the generalized Gaussian models (GGM. We have shown that Gabor filter developed in this work gives the classification rate greater than the results obtained by Generalized Gaussian model. The main contribution of this work is the generation of the filter banks able to give an optimal filter bank for a given texture and in particular for radar image textures

  14. Implementation of Pulse Radar Waveform Based on Software Radio Platform

    OpenAIRE

    Wang Dong; Dong Jian; Xiao Shunping

    2015-01-01

    Based on the frequency and phase modulated signal, the authors design some commonly-used pulse radar baseband waveform, such as linear frequency modulated waveform, nonlinear frequency modulated waveform, Costas waveform, Barker coding waveform and multi-phase coded waveform, and the authors compare their performance, such as the peak side lobe ratio, the Rayleigh resolution in time and distance resolution. Then, based on the software radio platform NI PXIe-5644R, the authors design the timin...

  15. Logarithmic Laplacian Prior Based Bayesian Inverse Synthetic Aperture Radar Imaging.

    Science.gov (United States)

    Zhang, Shuanghui; Liu, Yongxiang; Li, Xiang; Bi, Guoan

    2016-04-28

    This paper presents a novel Inverse Synthetic Aperture Radar Imaging (ISAR) algorithm based on a new sparse prior, known as the logarithmic Laplacian prior. The newly proposed logarithmic Laplacian prior has a narrower main lobe with higher tail values than the Laplacian prior, which helps to achieve performance improvement on sparse representation. The logarithmic Laplacian prior is used for ISAR imaging within the Bayesian framework to achieve better focused radar image. In the proposed method of ISAR imaging, the phase errors are jointly estimated based on the minimum entropy criterion to accomplish autofocusing. The maximum a posterior (MAP) estimation and the maximum likelihood estimation (MLE) are utilized to estimate the model parameters to avoid manually tuning process. Additionally, the fast Fourier Transform (FFT) and Hadamard product are used to minimize the required computational efficiency. Experimental results based on both simulated and measured data validate that the proposed algorithm outperforms the traditional sparse ISAR imaging algorithms in terms of resolution improvement and noise suppression.

  16. Graphene based tunable fractal Hilbert curve array broadband radar absorbing screen for radar cross section reduction

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xianjun, E-mail: xianjun.huang@manchester.ac.uk [School of Electrical and Electronic Engineering, University of Manchester, Manchester M13 9PL (United Kingdom); College of Electronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China); Hu, Zhirun [School of Electrical and Electronic Engineering, University of Manchester, Manchester M13 9PL (United Kingdom); Liu, Peiguo [College of Electronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

    2014-11-15

    This paper proposes a new type of graphene based tunable radar absorbing screen. The absorbing screen consists of Hilbert curve metal strip array and chemical vapour deposition (CVD) graphene sheet. The graphene based screen is not only tunable when the chemical potential of the graphene changes, but also has broadband effective absorption. The absorption bandwidth is from 8.9GHz to 18.1GHz, ie., relative bandwidth of more than 68%, at chemical potential of 0eV, which is significantly wider than that if the graphene sheet had not been employed. As the chemical potential varies from 0 to 0.4eV, the central frequency of the screen can be tuned from 13.5GHz to 19.0GHz. In the proposed structure, Hilbert curve metal strip array was designed to provide multiple narrow band resonances, whereas the graphene sheet directly underneath the metal strip array provides tunability and averagely required surface resistance so to significantly extend the screen operation bandwidth by providing broadband impedance matching and absorption. In addition, the thickness of the screen has been optimized to achieve nearly the minimum thickness limitation for a nonmagnetic absorber. The working principle of this absorbing screen is studied in details, and performance under various incident angles is presented. This work extends applications of graphene into tunable microwave radar cross section (RCS) reduction applications.

  17. Radar target recognition based on micro-Doppler effect

    Institute of Scientific and Technical Information of China (English)

    DONG Wei-guang; LI Yan-jun

    2008-01-01

    Mechanical vibration of target structures will modulate the phase function of radar backscattering, and will induce thefrequency modulation of returned signals from the target. It generates a side bands of the target body Doppler frequencyshift, which is helpful for target recognition. Based on this.a micro-Doppler atomic storehouse is built for the targetrecognition, and four kinds of common classifiers are used separately to perform the classified recognition. The simulationexperimental results show that this method has high recognition rate above 90%.

  18. Polarization-Based Radar Detection in Sea Clutter

    Science.gov (United States)

    2015-02-27

    Report 3. DATES COVERED (From - To) 01-04-2012 to 28-02-2015 4. TITLE AND SUBTITLE Polarization -Based Radar Detection in Sea Clutter 5a...14. ABSTRACT The goal of the proposed research is to characterize and model polarization -related behaviors of sea clutter and to use these models...that is to be exploited in this new form of detection is termed polarization mode dispersion (PMD), which is characterized by a spread in the received

  19. Mimo radar waveform design for spectrum sharing with cellular systems a Matlab based approach

    CERN Document Server

    Khawar, Awais; Clancy, T Charles

    2016-01-01

    This book discusses spectrum sharing between cellular systems and radars. The book addresses a novel way to design radar waveforms that can enable spectrum sharing between radars and communication systems, without causing interference to communication systems, and at the same time achieving radar objectives of target detection, estimation, and tracking. The book includes a MATLAB-based approach, which provides reader with a way to learn, experiment, compare, and build on top of existing algorithms.

  20. Duct heights inferred from radar sea clutter using proper orthogonal bases

    Science.gov (United States)

    Fountoulakis, Vasileios; Earls, Christopher

    2016-10-01

    Maritime electromagnetic (EM)-based communication and detection systems are strongly influenced by meteorological conditions, as they can cause anomalous electromagnetic propagation within the surface layer. To predict the performance of such systems, detailed knowledge of the refractivity profile is required. In recent years, refractivity from clutter (RFC) methods has been developed to estimate this refractivity profile by measuring radar clutter return from the rough ocean surface. The current work proposes an RFC framework that utilizes a novel surrogate model for EM propagation. The surrogate model is based on an offline created library of sparsely sampled field data of clutter returns, compressed into proper orthogonal bases, and indexed on specific surface layer refractive parameters. By exploiting the Riemannian manifold structure of the space that proper orthogonal bases occur in, we are able to interpolate among them. This, then, enables us to use the surrogate model in an inverse problem setting, whose goal is to uncover in situ maritime EM propagation conditions efficiently. We demonstrate the feasibility of our proposed surrogate model-based RFC approach for evaporation duct by testing it with field data obtained from an experimental campaign.

  1. New Precision Guidance Method Based on Bistatic Synthetic Apterture Radar

    Institute of Scientific and Technical Information of China (English)

    YANG Chun; ZENG Tao

    2008-01-01

    A new method is presented to improve guidance precision.This method is based on histatic synthetic aperture radar.The illuminator works in side looking mode,providing the synthetic aperture and the receiver is disposed on the seeker which operates in the forward looking mode.The receiving antenna is composed of four sub-antennas and so four synthetic aperture radar(SAR)images are to be generated.Target is positioned in SAR images by image matching.The bearing and elevation of image element of target are measured by the principle of monopulse angular measurement.Theory of the proposed method is derived and simulation on bearing measurement is done.Simulation shows that the method is valid and if SNR of target's image is above 30 dB.the angular measuring difference is witbin the confines of 0.04 degree.

  2. Radar-based collision avoidance for unmanned surface vehicles

    Science.gov (United States)

    Zhuang, Jia-yuan; Zhang, Lei; Zhao, Shi-qi; Cao, Jian; Wang, Bo; Sun, Han-bing

    2016-12-01

    Unmanned surface vehicles (USVs) have become a focus of research because of their extensive applications. To ensure safety and reliability and to perform complex tasks autonomously, USVs are required to possess accurate perception of the environment and effective collision avoidance capabilities. To achieve these, investigation into realtime marine radar target detection and autonomous collision avoidance technologies is required, aiming at solving the problems of noise jamming, uneven brightness, target loss, and blind areas in marine radar images. These technologies should also satisfy the requirements of real-time and reliability related to high navigation speeds of USVs. Therefore, this study developed an embedded collision avoidance system based on the marine radar, investigated a highly real-time target detection method which contains adaptive smoothing algorithm and robust segmentation algorithm, developed a stable and reliable dynamic local environment model to ensure the safety of USV navigation, and constructed a collision avoidance algorithm based on velocity obstacle (V-obstacle) which adjusts the USV's heading and speed in real-time. Sea trials results in multi-obstacle avoidance firstly demonstrate the effectiveness and efficiency of the proposed avoidance system, and then verify its great adaptability and relative stability when a USV sailing in a real and complex marine environment. The obtained results will improve the intelligent level of USV and guarantee the safety of USV independent sailing.

  3. Measurement Matrix Design for Compressive Sensing Based MIMO Radar

    CERN Document Server

    Yu, Y; Poor, H V

    2011-01-01

    In colocated multiple-input multiple-output (MIMO) radar using compressive sensing (CS), a receive node compresses its received signal via a linear transformation, referred to as measurement matrix. The samples are subsequently forwarded to a fusion center, where an L1-optimization problem is formulated and solved for target information. CS-based MIMO radar exploits the target sparsity in the angle-Doppler-range space and thus achieves the high localization performance of traditional MIMO radar but with many fewer measurements. The measurement matrix is vital for CS recovery performance. This paper considers the design of measurement matrices that achieve an optimality criterion that depends on the coherence of the sensing matrix (CSM) and/or signal-to-interference ratio (SIR). The first approach minimizes a performance penalty that is a linear combination of CSM and the inverse SIR. The second one imposes a structure on the measurement matrix and determines the parameters involved so that the SIR is enhanced...

  4. Radar-Derived Quantitative Precipitation Estimation Based on Precipitation Classification

    Directory of Open Access Journals (Sweden)

    Lili Yang

    2016-01-01

    Full Text Available A method for improving radar-derived quantitative precipitation estimation is proposed. Tropical vertical profiles of reflectivity (VPRs are first determined from multiple VPRs. Upon identifying a tropical VPR, the event can be further classified as either tropical-stratiform or tropical-convective rainfall by a fuzzy logic (FL algorithm. Based on the precipitation-type fields, the reflectivity values are converted into rainfall rate using a Z-R relationship. In order to evaluate the performance of this rainfall classification scheme, three experiments were conducted using three months of data and two study cases. In Experiment I, the Weather Surveillance Radar-1988 Doppler (WSR-88D default Z-R relationship was applied. In Experiment II, the precipitation regime was separated into convective and stratiform rainfall using the FL algorithm, and corresponding Z-R relationships were used. In Experiment III, the precipitation regime was separated into convective, stratiform, and tropical rainfall, and the corresponding Z-R relationships were applied. The results show that the rainfall rates obtained from all three experiments match closely with the gauge observations, although Experiment II could solve the underestimation, when compared to Experiment I. Experiment III significantly reduced this underestimation and generated the most accurate radar estimates of rain rate among the three experiments.

  5. Comparison of airborne radar altimeter and ground-based Ku-band radar measurements on the ice cap Austfonna, Svalbard

    Directory of Open Access Journals (Sweden)

    O. Brandt

    2008-11-01

    Full Text Available We compare coincident data from the European Space Agency's Airborne SAR/Interferometric Radar Altimeter System (ASIRAS with ground-based Very High Bandwidth (VHB stepped-frequency radar measurements in the Ku-band. The ASIRAS instrument obtained data from ~700 m above the surface, using a 13.5 GHz center frequency and a 1 GHz bandwidth. The ground-based VHB radar measurements were acquired using the same center frequency, but with a variable bandwidth of either 1 or 8 GHz. Four sites were visited with the VHB radar; two sites within the transition region from superimposed ice to firn, and two sites in the long-term firn area (wet-snow zone. The greater bandwidth VHB measurements show that the first peak in the airborne data is a composite of the return from the surface (i.e. air-snow interface and returns of similar or stronger amplitude from reflectors in the upper ~30 cm of the subsurface. The peak position in the airborne data is thus not necessarily a good proxy for the surface since the maximum and width of the first return depend on the degree of interference between surface and subsurface reflectors. The major response from the winter snowpack was found to be caused by units of thin crust/ice layers (0.5–2 mm surrounded by large crystals (>3 mm. In the airborne data, it is possible to track such layers for tens of kilometers. The winter snowpack lacked thicker ice layers. The last year's summer surface, characterized by a low density large crystal layer overlaying a harder denser layer, gives a strong radar response, frequently the strongest. The clear relationship observed between the VHB and ASIRAS waveforms, justifies the use of ground-based radar measurements in the validation of air- or spaceborne radars.

  6. Techniques for Radar Imaging Based on MUSIC Algorithm

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    At first, the radar target scattering centers model and MUSIC algorithm are analyzed in this paper. How to efficiently set the parameters of the MUSIC algorithms is given by a great deal of simulated radar data in experiments. After that, according to measured data from two kinds of plane targets on fully polarized and high range resolution radar system, the author mainly investigated particular utilization of MUSIC algorithm in radar imaging. And two-dimensional radar images are generated for two targets measured in compact range. In the end, a conclusion is drew about the relation of radar target scattering properties and imaging results.

  7. NOAA Next Generation Radar (NEXRAD) Level II Base Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset consists of Level II weather radar data collected from Next-Generation Radar (NEXRAD) stations located in the contiguous United States, Alaska, Hawaii,...

  8. Car collision sensor based on a noise radar

    OpenAIRE

    2005-01-01

    This article presents the study of a car collision radar system. Previous research led to a mock-up working in the10GHz band, based on a pseudo-noise and a correlation process. This current study started from a marketed microwave sensor (Transmitter-Receiver Unit) connected to an interface I/O and a processing module. As a first step, and to define the system architecture, the module was simulated on a LabView platform. Different modulations were tested to evaluate the main limitations of the...

  9. Low probability of intercept-based adaptive radar waveform optimization in signal-dependent clutter for joint radar and cellular communication systems

    Science.gov (United States)

    Shi, Chenguang; Salous, Sana; Wang, Fei; Zhou, Jianjiang

    2016-12-01

    In this paper, we investigate the problem of low probability of intercept (LPI)-based adaptive radar waveform optimization in signal-dependent clutter for joint radar and cellular communication systems, where the radar system optimizes the transmitted waveform such that the interference caused to the cellular communication systems is strictly controlled. Assuming that the precise knowledge of the target spectra, the power spectral densities (PSDs) of signal-dependent clutters, the propagation losses of corresponding channels and the communication signals is known by the radar, three different LPI based criteria for radar waveform optimization are proposed to minimize the total transmitted power of the radar system by optimizing the multicarrier radar waveform with a predefined signal-to-interference-plus-noise ratio (SINR) constraint and a minimum required capacity for the cellular communication systems. These criteria differ in the way the communication signals scattered off the target are considered in the radar waveform design: (1) as useful energy, (2) as interference or (3) ignored altogether. The resulting problems are solved analytically and their solutions represent the optimum power allocation for each subcarrier in the multicarrier radar waveform. We show with numerical results that the LPI performance of the radar system can be significantly improved by exploiting the scattered echoes off the target due to cellular communication signals received at the radar receiver.

  10. Comparison of the TRMM Precipitation Radar rainfall estimation with ground-based disdrometer and radar measurements in South Greece

    Science.gov (United States)

    Ioannidou, Melina P.; Kalogiros, John A.; Stavrakis, Adrian K.

    2016-11-01

    The performance of the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) rainfall estimation algorithm is assessed, locally, in Crete island, south Greece, using data from a 2D-video disdrometer and a ground-based, X-band, polarimetric radar. A three-parameter, normalized Gamma drop size distribution is fitted to the disdrometer rain spectra; the latter are classified in stratiform and convective rain types characterized by different relations between distribution parameters. The method of moments estimates more accurately the distribution parameters than the best fit technique, which exhibits better agreement with and is more biased by the observed droplet distribution at large diameter values. Power laws between the radar reflectivity factor (Z) and the rainfall rate (R) are derived from the disdrometer data. A significant diversity of the prefactor and the exponent of the estimated power laws is observed, depending on the scattering model and the regression technique. The Z-R relationships derived from the disdrometer data are compared to those obtained from TRMM-PR data. Generally, the power laws estimated from the two datasets are different. Specifically, the greater prefactor found for the disdrometer data suggests an overestimation of rainfall rate by the TRMM-PR algorithm for light and moderate stratiform rain, which was the main rain type in the disdrometer dataset. Finally, contemporary data from the TRMM-PR and a ground-based, X-band, polarimetric radar are analyzed. Comparison of the corresponding surface rain rates for a rain event with convective characteristics indicates a large variability of R in a single TRMM-PR footprint, which typically comprises several hundreds of radar pixels. Thus, the coarse spatial resolution of TRMM-PR may lead to miss of significant high local peaks of convective rain. Also, it was found that the high temporal variability of convective rain may introduce significant errors in the estimation of bias of

  11. Radar-to-Radar Interference Suppression for Distributed Radar Sensor Networks

    OpenAIRE

    Wen-Qin Wang; Huaizong Shao

    2014-01-01

    Radar sensor networks, including bi- and multi-static radars, provide several operational advantages, like reduced vulnerability, good system flexibility and an increased radar cross-section. However, radar-to-radar interference suppression is a major problem in distributed radar sensor networks. In this paper, we present a cross-matched filtering-based radar-to-radar interference suppression algorithm. This algorithm first uses an iterative filtering algorithm to suppress the radar-to-radar ...

  12. Logarithmic Laplacian Prior Based Bayesian Inverse Synthetic Aperture Radar Imaging

    Directory of Open Access Journals (Sweden)

    Shuanghui Zhang

    2016-04-01

    Full Text Available This paper presents a novel Inverse Synthetic Aperture Radar Imaging (ISAR algorithm based on a new sparse prior, known as the logarithmic Laplacian prior. The newly proposed logarithmic Laplacian prior has a narrower main lobe with higher tail values than the Laplacian prior, which helps to achieve performance improvement on sparse representation. The logarithmic Laplacian prior is used for ISAR imaging within the Bayesian framework to achieve better focused radar image. In the proposed method of ISAR imaging, the phase errors are jointly estimated based on the minimum entropy criterion to accomplish autofocusing. The maximum a posterior (MAP estimation and the maximum likelihood estimation (MLE are utilized to estimate the model parameters to avoid manually tuning process. Additionally, the fast Fourier Transform (FFT and Hadamard product are used to minimize the required computational efficiency. Experimental results based on both simulated and measured data validate that the proposed algorithm outperforms the traditional sparse ISAR imaging algorithms in terms of resolution improvement and noise suppression.

  13. Subarray-based FDA radar to counteract deceptive ECM signals

    Science.gov (United States)

    Abdalla, Ahmed; Wang, Wen-Qin; Yuan, Zhao; Mohamed, Suhad; Bin, Tang

    2016-12-01

    In recent years, the frequency diverse array (FDA) radar concept has attracted extensive attention, as it may benefit from a small frequency increment, compared to the carrier frequency across the array elements and thereby achieve an array factor that is a function of the angle, the time, and the range which is superior to the conventional phase array radar (PAR). However, limited effort on the subject of FDA in electronic countermeasure scenarios, especially in the presence of mainbeam deceptive jamming, has been published. Basic FDA is not desirable for anti-jamming applications, due to the range-angle coupling response of targets. In this paper, a novel method based on subarrayed FDA signal processing is proposed to counteract deceptive ECM signals. We divide the FDA array into multiple subarrays, each of which employs a distinct frequency increment. As a result, in the subarray-based FDA, the desired target can be distinguished at subarray level in joint range-angle-Doppler domain by utilizing the fact that the jammer generates false targets with the same ranges to each subarray without reparations. The performance assessment shows that the proposed solution is effective for deceptive ECM targets suppression. The effectiveness is verified by simulation results.

  14. Localization of an air target by means of GNSS-based multistatic radar

    Science.gov (United States)

    Akhmedov, Daulet Sh.; Raskaliyev, Almat S.

    2016-08-01

    The possibility of utilizing transmitters of opportunity for target detection, tracking and positioning is of great interest to the radar community. In particular the optional use of Global Navigation Satellite System (GNSS) has lately triggered scientific research that has purpose to take advantage of this source of signal generation for passive radar. Number of studies have been conducted previously on development of GNSS-based bistatic and multistatic radars for detection and range estimation to the object located in the close atmosphere. To further enrich research in this area, we present a novel method for coordinate determination of the air target by means of the GNSS-based multistatic radar.

  15. Experiments on a Ground-Based Tomographic Synthetic Aperture Radar

    Directory of Open Access Journals (Sweden)

    Hoonyol Lee

    2016-08-01

    Full Text Available This paper presents the development and experiment of three-dimensional image formation by using a ground-based tomographic synthetic aperture radar (GB-TomoSAR system. GB-TomoSAR formulates two-dimensional synthetic aperture by the motion of antennae, both in azimuth and vertical directions. After range compression, three-dimensional image focusing is performed by applying Deramp-FFT (Fast Fourier Transform algorithms, both in azimuth and vertical directions. Geometric and radiometric calibrations were applied to make an image cube, which is then projected into range-azimuth and range-vertical cross-sections for visualization. An experiment with a C-band GB-TomoSAR system with a scan length of 2.49 m and 1.86 m in azimuth and vertical-direction, respectively, shows distinctive three-dimensional radar backscattering of stable buildings and roads with resolutions similar to the theoretical values. Unstable objects such as trees and moving cars generate severe noise due to decorrelation during the eight-hour image-acquisition time.

  16. Radar-Based Analysis of Convective Storms over Northwestern Italy

    Directory of Open Access Journals (Sweden)

    Paolo Davini

    2011-12-01

    Full Text Available Thunderstorms may cause large damages to infrastructures and population, therefore the possible identification of the areas with the highest occurrence of these events is especially relevant. Nevertheless, few extensive studies of these phenomena with high spatial and temporal resolution have been carried out in the Alps and none of them includes North-western Italy. To analyze thunderstorm events, the data of the meteorological radar network of the regional meteorological service of Piedmont region (ARPA Piemonte have been used in this work. The database analyzed includes all thunderstorms occurred during the warm months (April to September of a 6-year period (2005–2010. The tracks of each storm have been evaluated using a storm tracking algorithm. Several characteristics of the storms have been analyzed, such as the duration, the spatial and the temporaldistribution, the direction and the distance travelled. Obtained results revealed several important characteristics that may be useful for nowcasting purposes providing a first attempt of radar-based climatology in the considered region.

  17. Short range automotive radar based on UWB pseudo-random coding

    OpenAIRE

    2007-01-01

    In this paper, a radar system for short range automotive application based on ultra-wideband (UWB) technology is studied. UWB uses very short pulses, so that the spectrum of the transmitted signals may spread over several Gigahertzes. In order to increase, from one part, the resolution in distance of this radar system and to avoid, from another part, multi-users interferences for an optimal detectability, we propose to improve the radar performances by using coding techniques. It consists on ...

  18. The radar signal simulation based on the analysis of Pulse-Doppler radar for digital signal processing implementation in the Matlab environment

    Directory of Open Access Journals (Sweden)

    Yu. Yu. Reutskaya

    2015-03-01

    Full Text Available Introduction. The complexity of modern radar (RLS due to their versatility and the need to adapt to the interference situation is constantly changed. The models to test the basic ideas to be implemented in the radar are required. It is important to consider the main stages of the simulation of the radar signal based on the analysis of radar operation. Problem statement. The creation of a universal analytical model to build a radar signal in Matlab is considered. Theoretical results. Stages and results of the radar signal simulation are presented and based on the analysis of pulse – Doppler radar. Basic analytical relations ofthe task are given. Features of simulation when signals of additive fluctuation noise and clutter together with the echo target signals arrive are considered. Conclusion. As a result of analysis of radar interference conditions on the basis of existing relations an optimum variant model of radar signal in Matlab environment is reached. This is the basis for further evaluation of the digital processing effectiveness of the radar signal to background noise and interference (clutter, namely to determine the distance to targets and target’s speeds. . The main advantages of the Mellin transform using for recognizing signals at different scales are presented is conclusions.

  19. FloodAlert: a simplified radar-based EWS for urban flood warning

    OpenAIRE

    Llort Pavon, Xavier; Sánchez-Diezma Guijarro, Rafael; Rodríguez, Álvaro; De Sancho, David; Berenguer Ferrer, Marc; Sempere Torres, Daniel

    2014-01-01

    In this work we present FloodAlert, a simplified flood Early Warning System [EWS] based on the use of radar observations and radar nowcasting to issue local flood warnings. It is a web-based platform and it is complemented with a flexible and powerful dissemination module.

  20. Radar Emitter Signal Recognition Based on Complexity Features

    Institute of Scientific and Technical Information of China (English)

    张葛祥; 金炜东; 胡来招

    2004-01-01

    Intra-pulse characteristics of different radar emitter signals reflect on signal waveform by way of changing frequency, phase and amplitude. A novel approach was proposed to extract complexity features of radar emitter signals in a wide range of signal-to-noise ratio ( SNR), and radial basis probability neural network (RBPNN) was used to recognize different radar emitter signals. Complexity features, including Lempel-Ziv complexity (LZC) and correlation dimension (CD), can measure the complexity and irregularity of signals, which mirrors the intra-pulse modulation laws of radar emitter signals. In an experiment, LZC and CD features of 10 typical radar emitter signals were extracted and RBPNN was applied to identify the 10 radar emitter signals. Simulation results show that the proposed approach is effective and has good application values because average accurate recognition rate is high when SNR varies in a wide range.

  1. A Wing Pod-based Millimeter Wave Cloud Radar on HIAPER

    Science.gov (United States)

    Vivekanandan, Jothiram; Tsai, Peisang; Ellis, Scott; Loew, Eric; Lee, Wen-Chau; Emmett, Joanthan

    2014-05-01

    One of the attractive features of a millimeter wave radar system is its ability to detect micron-sized particles that constitute clouds with lower than 0.1 g m-3 liquid or ice water content. Scanning or vertically-pointing ground-based millimeter wavelength radars are used to study stratocumulus (Vali et al. 1998; Kollias and Albrecht 2000) and fair-weather cumulus (Kollias et al. 2001). Airborne millimeter wavelength radars have been used for atmospheric remote sensing since the early 1990s (Pazmany et al. 1995). Airborne millimeter wavelength radar systems, such as the University of Wyoming King Air Cloud Radar (WCR) and the NASA ER-2 Cloud Radar System (CRS), have added mobility to observe clouds in remote regions and over oceans. Scientific requirements of millimeter wavelength radar are mainly driven by climate and cloud initiation studies. Survey results from the cloud radar user community indicated a common preference for a narrow beam W-band radar with polarimetric and Doppler capabilities for airborne remote sensing of clouds. For detecting small amounts of liquid and ice, it is desired to have -30 dBZ sensitivity at a 10 km range. Additional desired capabilities included a second wavelength and/or dual-Doppler winds. Modern radar technology offers various options (e.g., dual-polarization and dual-wavelength). Even though a basic fixed beam Doppler radar system with a sensitivity of -30 dBZ at 10 km is capable of satisfying cloud detection requirements, the above-mentioned additional options, namely dual-wavelength, and dual-polarization, significantly extend the measurement capabilities to further reduce any uncertainty in radar-based retrievals of cloud properties. This paper describes a novel, airborne pod-based millimeter wave radar, preliminary radar measurements and corresponding derived scientific products. Since some of the primary engineering requirements of this millimeter wave radar are that it should be deployable on an airborne platform

  2. Identification of Mine-Shaped Objects based on an Efficient Phase Stepped-Frequency Radar Approach

    DEFF Research Database (Denmark)

    Sørensen, Helge Bjarup Dissing; Jakobsen, Kaj Bjarne; Nymann, Ole

    1997-01-01

    a radar probe is moved automatically to measure in each grid point a set of reflection coefficients from which phase and amplitude information are extracted. Based on a simple processing of the phase information, quarternary image and template cross-correlation a successful detection of metal- and non...... clearance. Our approach consists of three stages, the phase stepped-frequency radar method, generation of a quarternary image and template crosscorrelation. The phase stepped-frequency radar method belongs to the class of stepped-frequency radar methods. In a two-dimensional mesh-grid above the ground...

  3. Radar equations for modern radar

    CERN Document Server

    Barton, David K

    2012-01-01

    Based on the classic Radar Range-Performance Analysis from 1980, this practical volume extends that work to ensure applicability of radar equations to the design and analysis of modern radars. This unique book helps you identify what information on the radar and its environment is needed to predict detection range. Moreover, it provides equations and data to improve the accuracy of range calculations. You find detailed information on propagation effects, methods of range calculation in environments that include clutter, jamming and thermal noise, as well as loss factors that reduce radar perfo

  4. Validation of TRMM Precipitation Radar Through Comparison of its Multi-Year Measurements to Ground-Based Radar

    Science.gov (United States)

    Liao, Liang; Meneghini, Robert

    2010-01-01

    A procedure to accurately resample spaceborne and ground-based radar data is described, and then applied to the measurements taken from the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) and the ground-based Weather Surveillance Radar-1988 Doppler (WSR-88D or WSR) for the validation of the PR measurements and estimates. Through comparisons with the well-calibrated, non-attenuated WSR at Melbourne, Florida for the period 1998-2007, the calibration of the Precipitation Radar (PR) aboard the TRMM satellite is checked using measurements near the storm top. Analysis of the results indicates that the PR, after taking into account differences in radar reflectivity factors between the PR and WSR, has a small positive bias of 0.8 dB relative to the WSR, implying a soundness of the PR calibration in view of the uncertainties involved in the comparisons. Comparisons between the PR and WSR reflectivities are also made near the surface for evaluation of the attenuation-correction procedures used in the PR algorithms. It is found that the PR attenuation is accurately corrected in stratiform rain but is underestimated in convective rain, particularly in heavy rain. Tests of the PR estimates of rainfall rate are conducted through comparisons in the overlap area between the TRMM overpass and WSR scan. Analyses of the data are made both on a conditional basis, in which the instantaneous rain rates are compared only at those pixels where both the PR and WSR detect rain, and an unconditional basis, in which the area-averaged rain rates are estimated independently for the PR and WSR. Results of the conditional rain comparisons show that the PR-derived rain is about 9% greater and 19% less than the WSR estimates for stratiform and convective storms, respectively. Overall, the PR tends to underestimate the conditional mean rain rate by 8% for all rain categories, a finding that conforms to the results of the area-averaged rain (unconditional) comparisons.

  5. 5 year radar-based rainfall statistics: disturbances analysis and development of a post-correction scheme for the German radar composite

    Directory of Open Access Journals (Sweden)

    A. Wagner

    2015-02-01

    Full Text Available A radar-based rainfall statistic demands high quality data that provide realistic precipitation amounts in space and time. Instead of correcting single radar images, we developed a post-correction scheme for long-term composite radar data that corrects corrupted areas, but preserves the original precipitation patterns. The post-correction scheme is based on a 5 year statistical analysis of radar composite data and its constituents. The accumulation of radar images reveals artificial effects that are not visible in the individual radar images. Some of them are already inherent to single radar data such as the effect of increasing beam height, beam blockage or clutter remnants. More artificial effects are introduced in the process of compositing such as sharp gradients at the boundaries of overlapping areas due to different beam heights and resolution. The cause of these disturbances, their behaviour with respect to reflectivity level, season or altitude is analysed based on time-series of two radar products: the single radar reflectivity product PX for each of the 16 radar systems of the German Meteorological Service (DWD for the time span 2000 to 2006 and the radar composite product RX of DWD from 2005 through to 2009. These statistics result in additional quality information on radar data that is not available elsewhere. The resulting robust characteristics of disturbances, e.g. the dependency of the frequencies of occurrence of radar reflectivities on beam height, are then used as a basis for the post-correction algorithm. The scheme comprises corrections for shading effects and speckles, such as clutter remnants or overfiltering, as well as for systematic differences in frequencies of occurrence of radar reflectivities between the near and the far ranges of individual radar sites. An adjustment to rain gauges is also included. Applying this correction, the Root-Mean-Square-Error for the comparison of radar derived annual rain amounts with

  6. Salient Feature Identification and Analysis using Kernel-Based Classification Techniques for Synthetic Aperture Radar Automatic Target Recognition

    Science.gov (United States)

    2014-03-27

    SALIENT FEATURE IDENTIFICATION AND ANALYSIS USING KERNEL-BASED CLASSIFICATION TECHNIQUES FOR SYNTHETIC APERTURE RADAR AUTOMATIC TARGET RECOGNITION...FEATURE IDENTIFICATION AND ANALYSIS USING KERNEL-BASED CLASSIFICATION TECHNIQUES FOR SYNTHETIC APERTURE RADAR AUTOMATIC TARGET RECOGNITION THESIS Presented...SALIENT FEATURE IDENTIFICATION AND ANALYSIS USING KERNEL-BASED CLASSIFICATION TECHNIQUES FOR SYNTHETIC APERTURE RADAR AUTOMATIC TARGET RECOGNITION

  7. On reconciling ground-based with spaceborne normalized radar cross section measurements

    DEFF Research Database (Denmark)

    Baumgartner, Francois; Munk, Jens; Jezek, K C

    2002-01-01

    This study examines differences in the normalized radar cross section, derived from ground-based versus spaceborne radar data. A simple homogeneous half-space model, indicates that agreement between the two improves as 1) the distance from the scatterer is increased; and/or 2) the extinction...

  8. Correlating Flight Behavior and Radar Measurements for Species Based Classification of Bird Radar Echoes for Wind Energy Site Assessment

    Science.gov (United States)

    Werth, S. P.; Frasier, S. J.

    2015-12-01

    Wind energy is one of the fastest-growing segments of the world energy market, offering a clean and abundant source of electricity. However, wind energy facilities can have detrimental effects on wildlife, especially birds and bats. Monitoring systems based on marine navigation radar are often used to quantify migration near potential wind sites, but the ability to reliably distinguish between bats and different varieties of birds has not been practically achieved. This classification capability would enable wind site selection that protects more vulnerable species, such as bats and raptors. Flight behavior, such as wing beat frequency, changes in speed, or changes in orientation, are known to vary by species [1]. The ability to extract these properties from radar data could ultimately enable a species based classification scheme. In this work, we analyze the relationship between radar measurements and bird flight behavior in echoes from avifauna. During the 2014 fall migration season, the UMass dual polarized weather radar was used to collect low elevation observations of migrating birds as they traversed through a fixed antenna beam. The radar was run during the night time, in clear-air conditions. Data was coherently integrated, and detections of biological targets exceeding an SNR threshold were extracted. Detections without some dominant frequency content (i.e. clear periodicity, potentially the wing beat frequency) were removed from the sample in order to isolate observations suspected to contain a single species or bird. For the remaining detections, measurements including the polarimetric products and the Doppler spectrum were extracted at each time step over the duration of the observation. The periodic and time changing nature of some of these different measurements was found to have a strong correlation with flight behavior (i.e. flapping vs. gliding behavior). Assumptions about flight behavior and orientation were corroborated through scattering

  9. HIGH RESOLUTION RANGE PROFILE FORMATION BASED ON LFM SIGNAL FUSION OF MULTIPLE RADARS

    Institute of Scientific and Technical Information of China (English)

    Wang Cheng; Hu Weidong; Du Xiaoyong; Yu Wenxian

    2007-01-01

    This paper presents a new method of High Resolution Range (HRR) profile formation based on Linear Frequency Modulation (LFM) signal fusion of multiple radars with multiple frequency bands.The principle of the multiple radars signal fusion improving the range resolution is analyzed. With the analysis of return signals received by two radars, it is derived that the phase difference between the echoes varies almost linearly with respect to the frequency if the distance between two radars is negligible compared with the radar observation distance. To compensate the phase difference, an entropy-minimization principle based compensation algorithm is proposed. During the fusion process, the B-splines interpolation method is applied to resample the signals for Fourier transform imaging. The theoretical analysis and simulations results show the proposed method can effectively increase signal bandwidth and provide a high resolution range profile.

  10. Polarimetric analysis of radar backscatter from ground-based scatterometers and wheat biomass monitoring with advanced synthetic aperture radar images

    Science.gov (United States)

    He, Lei; Tong, Ling; Li, Yuxia; Chen, Yan; Tan, Longfei; Guo, Caizheng

    2016-04-01

    This article presents an analysis of the scattering measurements for an entire wheat growth cycle by ground-based scatterometers at a frequency of 5.3 GHz. Since wheat ears are related to wheat growth and yield, the radar backscatter of wheat was analyzed at two different periods, i.e., with and without wheat ears. Simultaneously, parameters such as wheat and soil characteristics as well as volume scattering and soil scattering were analyzed for the two periods during the entire growth cycle. Wheat ears have been demonstrated to have a great influence on radar backscatter; therefore, a modified version of water-cloud model used for retrieving biomass should consider the effect of wheat ears. This work presents two retrieval models based on the water-cloud model and adopts the advanced integral equation model to simulate the soil backscatter before the heading stage and the backscatter from the layer under wheat ears after the heading stage. The research results showed that the biomass retrieved from the advanced synthetic aperture radar (ASAR) images to agree well with the data measured in situ after setting the modified water-cloud model for the growth stages with ears. Furthermore, it was concluded that wheat ears should form an essential component of theoretical modeling as they influence the final yield.

  11. Hardware-in-the-loop simulation technology of wide-band radar targets based on scattering center model

    Institute of Scientific and Technical Information of China (English)

    Huang Hao; Pan Minghai; Lu Zhijun

    2015-01-01

    Hardware-in-the-loop (HWIL) simulation technology can verify and evaluate the radar by simulating the radio frequency environment in an anechoic chamber. The HWIL simulation technology of wide-band radar targets can accurately generate wide-band radar target echo which stands for the radar target scattering characteristics and pulse modulation of radar transmitting sig-nal. This paper analyzes the wide-band radar target scattering properties first. Since the responses of target are composed of many separate scattering centers, the target scattering characteristic is restructured by scattering centers model. Based on the scattering centers model of wide-band radar target, the wide-band radar target echo modeling and the simulation method are discussed. The wide-band radar target echo is reconstructed in real-time by convoluting the transmitting signal to the target scattering parameters. Using the digital radio frequency memory (DRFM) system, the HWIL simulation of wide-band radar target echo with high accuracy can be actualized. A typical wide-band radar target simulation is taken to demonstrate the preferable simulation effect of the reconstruction method of wide-band radar target echo. Finally, the radar target time-domain echo and high-resolution range profile (HRRP) are given. The results show that the HWIL simulation gives a high-resolution range distribution of wide-band radar target scattering centers.

  12. Photoelectric radar servo control system based on ARM+FPGA

    Science.gov (United States)

    Wu, Kaixuan; Zhang, Yue; Li, Yeqiu; Dai, Qin; Yao, Jun

    2016-01-01

    In order to get smaller, faster, and more responsive requirements of the photoelectric radar servo control system. We propose a set of core ARM + FPGA architecture servo controller. Parallel processing capability of FPGA to be used for the encoder feedback data, PWM carrier modulation, A, B code decoding processing and so on; Utilizing the advantage of imaging design in ARM Embedded systems achieves high-speed implementation of the PID algorithm. After the actual experiment, the closed-loop speed of response of the system cycles up to 2000 times/s, in the case of excellent precision turntable shaft, using a PID algorithm to achieve the servo position control with the accuracy of + -1 encoder input code. Firstly, This article carry on in-depth study of the embedded servo control system hardware to determine the ARM and FPGA chip as the main chip with systems based on a pre-measured target required to achieve performance requirements, this article based on ARM chip used Samsung S3C2440 chip of ARM7 architecture , the FPGA chip is chosen xilinx's XC3S400 . ARM and FPGA communicate by using SPI bus, the advantage of using SPI bus is saving a lot of pins for easy system upgrades required thereafter. The system gets the speed datas through the photoelectric-encoder that transports the datas to the FPGA, Then the system transmits the datas through the FPGA to ARM, transforms speed datas into the corresponding position and velocity data in a timely manner, prepares the corresponding PWM wave to control motor rotation by making comparison between the position data and the velocity data setted in advance . According to the system requirements to draw the schematics of the photoelectric radar servo control system and PCB board to produce specially. Secondly, using PID algorithm to control the servo system, the datas of speed obtained from photoelectric-encoder is calculated position data and speed data via high-speed digital PID algorithm and coordinate models. Finally, a

  13. Development of software application dedicated to impulse- radar-based system for monitoring of human movements

    Science.gov (United States)

    Miękina, Andrzej; Wagner, Jakub; Mazurek, Paweł; Morawski, Roman Z.; Sudmann, Tobba T.; Børsheim, Ingebjørg T.; Øvsthus, Knut; Jacobsen, Frode F.; Ciamulski, Tomasz; Winiecki, Wiesław

    2016-11-01

    The importance of research on new technologies that could be employed in care services for elderly and disabled persons is highlighted. Advantages of radar sensors, when applied for non-invasive monitoring of such persons in their home environment, are indicated. A need for comprehensible visualisation of the intermediate results of measurement data processing is justified. Capability of an impulse-radar-based system to provide information, being of crucial importance for medical or healthcare personnel, are investigated. An exemplary software interface, tailored for non-technical users, is proposed, and preliminary results of impulse-radar-based monitoring of human movements are demonstrated.

  14. Fpga based L-band pulse doppler radar design and implementation

    Science.gov (United States)

    Savci, Kubilay

    As its name implies RADAR (Radio Detection and Ranging) is an electromagnetic sensor used for detection and locating targets from their return signals. Radar systems propagate electromagnetic energy, from the antenna which is in part intercepted by an object. Objects reradiate a portion of energy which is captured by the radar receiver. The received signal is then processed for information extraction. Radar systems are widely used for surveillance, air security, navigation, weather hazard detection, as well as remote sensing applications. In this work, an FPGA based L-band Pulse Doppler radar prototype, which is used for target detection, localization and velocity calculation has been built and a general-purpose Pulse Doppler radar processor has been developed. This radar is a ground based stationary monopulse radar, which transmits a short pulse with a certain pulse repetition frequency (PRF). Return signals from the target are processed and information about their location and velocity is extracted. Discrete components are used for the transmitter and receiver chain. The hardware solution is based on Xilinx Virtex-6 ML605 FPGA board, responsible for the control of the radar system and the digital signal processing of the received signal, which involves Constant False Alarm Rate (CFAR) detection and Pulse Doppler processing. The algorithm is implemented in MATLAB/SIMULINK using the Xilinx System Generator for DSP tool. The field programmable gate arrays (FPGA) implementation of the radar system provides the flexibility of changing parameters such as the PRF and pulse length therefore it can be used with different radar configurations as well. A VHDL design has been developed for 1Gbit Ethernet connection to transfer digitized return signal and detection results to PC. An A-Scope software has been developed with C# programming language to display time domain radar signals and detection results on PC. Data are processed both in FPGA chip and on PC. FPGA uses fixed

  15. An Energy Consumption Optimized Clustering Algorithm for Radar Sensor Networks Based on an Ant Colony Algorithm

    Directory of Open Access Journals (Sweden)

    Jiang Ting

    2010-01-01

    Full Text Available We optimize the cluster structure to solve problems such as the uneven energy consumption of the radar sensor nodes and random cluster head selection in the traditional clustering routing algorithm. According to the defined cost function for clusters, we present the clustering algorithm which is based on radio-free space path loss. In addition, we propose the energy and distance pheromones based on the residual energy and aggregation of the radar sensor nodes. According to bionic heuristic algorithm, a new ant colony-based clustering algorithm for radar sensor networks is also proposed. Simulation results show that this algorithm can get a better balance of the energy consumption and then remarkably prolong the lifetime of the radar sensor network.

  16. Study of detection performance of passive bistatic radars based on FM broadcast

    Institute of Scientific and Technical Information of China (English)

    Shan Tao; Tao Ran; Wang Yue; Zhou Siyong

    2007-01-01

    The passive bistatic radar based on the FM broadcast has inherent superiority with respect to its survivability. In this article, the ambiguity function (AF) and the cross ambiguity function (CAF) of the FM radio signal are analyzed and illustrated.The Kolmogorov Smirnov (K-S) test verifies that the amplitude probability density function of the CAF side lobes is exponential; the distribution of the target is also deduced. Finally, the detection performance of the passive radar is studied, and the result shows that this new type bistatic radar has favorable detection capability.

  17. Doppler weather Radar based Nowcasting of cyclone Ogni

    Indian Academy of Sciences (India)

    Soma Sen Roy; V Lakshmanan; S K Roy Bhowmik; S B Thampi

    2010-04-01

    In this paper, we describe offline analysis of Indian Doppler Weather Radar (DWR) data from cyclone Ogni using a suite of radar algorithms as implemented on NEXRAD and the advanced algorithms developed jointly by the National Severe Storms Laboratory (NSSL) and the University of Oklahoma. We demonstrate the applicability of the various algorithms to Indian radar data, the improvement in the quality control and evaluate the benefit of nowcasting capabilities in Indian conditions. New information about the tropical cyclone structure, as derived from application of the algorithms is also discussed in this study. Finally, we suggest improvements that could be made to the Indian data collection strategies, networking and real-time analysis. Since this is the first study of its kind to process and utilize DWR data in a tropical climate, the suggestions on real-time analysis and data collection strategies made in this paper, would in many cases, be beneficial to other countries embarking on DWR network modernization programs.

  18. Ultra-wideband noise radar based on optical waveform generation

    Science.gov (United States)

    Grodensky, Daniel; Kravitz, Daniel; Zadok, Avi

    2012-06-01

    A microwave-photonic, ultra-wideband (UWB) noise radar system is proposed and demonstrated. The system brings together photonic generation of UWB waveforms and fiber-optic distribution. The use of UWB noise provides high ranging resolution and better immunity to interception and jamming. Distribution over fibers allows for the separation the radar-operating personnel and equipment from the location of the front-end. The noise waveforms are generated using the amplified spontaneous emission that is associated with stimulated Brillouin scattering in a standard optical fiber, or with an erbium-doped fiber amplifier. Our experiments demonstrate a proof of concept for an integrated radar system, driven by optically generated UWB noise waveforms of more than 1 GHz bandwidth that are distributed over 10 km distance. The detection of concealed metallic object and the resolving of two targets with the anticipated ranging resolution are reported.

  19. Multistatic Wireless Fidelity Network Based Radar – Results of the Chrcynno Experiment

    Directory of Open Access Journals (Sweden)

    S. Rzewuski

    2014-04-01

    Full Text Available This paper presents the theory and experimental result of passive radar using WIFI transmitters as illuminators of opportunity. As a result of experiments conducted on 17th August 2013 at airfield Chrcynno a Cessna C208 airplane was detected and tracked using multistatic passive radar system based on low power signal from WIFI network nodes, which were acting as non cooperative illuminators of opportunity. In the experiment 3 wireless access points were communicating with each other and illuminating the radar scene (airfield. The direct reference and reflected (surveillance signals have been acquired and processed using specially developed algorithm presented in the paper. After signal processing using Passive Coherent Location methods target has been detected. This paper describes in details the algorithms and the results of the experiment for the multistatic passive radar based on the WIFI signal.

  20. Integrating radar and laser-based remote sensing techniques for monitoring structural deformation of archaeological monuments

    OpenAIRE

    Tapete D.; Casagli N.; Luzi G.; Fanti R.; Gigli G.; Leva D.

    2013-01-01

    Ground-Based Synthetic Aperture Radar Interferometry (GBInSAR) and Terrestrial Laser Scanning (TLS) were purposely integrated to obtain 3D interferometric radar point clouds to facilitate the spatial interpretation of displacements affecting archaeological monuments. The paper describes the procedure to implement this integrated approach in the real-world situations of surveillance of archaeological and built heritage. Targeted tests were carried out on the case study of the Domus Tiberiana s...

  1. Tracking method based on separation and combination of the measurements for radar and IR fusion system

    Institute of Scientific and Technical Information of China (English)

    Wang Qingchao; Wang Wenfei

    2009-01-01

    A new distributed fusion method of radar/infrared (IR) tracking system based on separation and combination of the measurements is proposed by analyzing the influence of rate measurement. The rate information separated from the radar measurements together with measurements of IR form a pseudo vector of IR, and the corresponding filter is designed. The results indicate that the method not only makes a great improvement to the local tracker's performance, but also improves the global tracking precision efficiently.

  2. A New Radar TBD Method Based on RD-CTS

    Institute of Scientific and Technical Information of China (English)

    MOLi; WUSiliang; MAOErke

    2005-01-01

    Track-before-detect (TBD) is a useful strategy for weak target detection that manages to integrate target energy along candidate trajectories and test whether the summation is large enough to declare a target. Several methods have been proposed to apply TBD in radar weak target detection, but none of them could make profitable use of the inherent characteristic of radar data. A simple and time saving radar TBD method is proposed, which is unique in an innovative Range-Doppler Candidate trajectories structure (RD-CTS). A number of candidate trajectories are hypothesized off-line, taking advantage of the correlation of the Doppler and range of each “root” image cell. Measurements along possible target trajectories are then integrated and a target is declared if the measurement sum, or merit function, exceeds a threshold. The CFAR (Constant false alarm rate) detection and false alarm probability determination are analyzed as well. Under a practical set of radar parameters, good detection performances are presented that at about 100% detection probability, 7.5dB SNR gain is achieved through 15-frame non-coherent integration.

  3. Numerical simulation and inversion of offshore area depth based on x-band microwave radar

    Institute of Scientific and Technical Information of China (English)

    WANG Li; WU Xiongbin; PI Xiaoshan; MA Ketao; LIU Jianfei; TIAN Yun

    2015-01-01

    A detection method of offshore area depth utilizing the x-band microwave radar is proposed. The method is based on the sea clutter imaging mechanism of microwave radar, and combined with dispersion equation of the liner wave theorem and least square method (LSM), consequently get the inversion results of water depth in the detected region. The wave monitoring system OSMAR-X exploited by the Ocean State Laborato-ry, Wuhan University, based on a microwave radar has proven to be a powerful tool to monitor ocean waves in time and space. Numerical simulation and inversion of offshore area depth are carried out here; since JONSWAP model can give description of stormy waves in different growth phase, it is suitable for simulation. Besides, some results from measured data detected by OSMAR-X x-band radar located at Longhai of Fujian Province, China, validates this method. The tendency of the average water depths inferred from the radar images is in good agreement with the tide level detected by Xiamen tide station. These promising results suggest the possibility of using OSMAR-X to monitor operationally morphodynamics in coastal zones. This method can be applied to both shore-based and shipborne x-band microwave radar.

  4. A Fast Method for Embattling Optimization of Ground-Based Radar Surveillance Network

    Science.gov (United States)

    Jiang, H.; Cheng, H.; Zhang, Y.; Liu, J.

    A growing number of space activities have created an orbital debris environment that poses increasing impact risks to existing space systems and human space flight. For the safety of in-orbit spacecraft, a lot of observation facilities are needed to catalog space objects, especially in low earth orbit. Surveillance of Low earth orbit objects are mainly rely on ground-based radar, due to the ability limitation of exist radar facilities, a large number of ground-based radar need to build in the next few years in order to meet the current space surveillance demands. How to optimize the embattling of ground-based radar surveillance network is a problem to need to be solved. The traditional method for embattling optimization of ground-based radar surveillance network is mainly through to the detection simulation of all possible stations with cataloged data, and makes a comprehensive comparative analysis of various simulation results with the combinational method, and then selects an optimal result as station layout scheme. This method is time consuming for single simulation and high computational complexity for the combinational analysis, when the number of stations increases, the complexity of optimization problem will be increased exponentially, and cannot be solved with traditional method. There is no better way to solve this problem till now. In this paper, target detection procedure was simplified. Firstly, the space coverage of ground-based radar was simplified, a space coverage projection model of radar facilities in different orbit altitudes was built; then a simplified objects cross the radar coverage model was established according to the characteristics of space objects orbit motion; after two steps simplification, the computational complexity of the target detection was greatly simplified, and simulation results shown the correctness of the simplified results. In addition, the detection areas of ground-based radar network can be easily computed with the

  5. A Radar-Based Climatology of Thunderstorm Days across New York State.

    Science.gov (United States)

    Falconer, Phillip D.

    1984-07-01

    Archived radar reports, derived from the National Weather Service radar network, were used to estimate the average annual frequencies of thunderstorm days across New York State for the period 1978-81. The archival records consist of manually-digitized radar (MDR) data, available on magnetic tapes and arranged as hourly, digitally-encoded radar reflectivity values within a high-resolution grid of reporting blocks, each 45 × 45 km. Analyses of these data made use of an experimentally-derived relationship between radar reflectivities and the presence and intensities of thunderstorms. The radar-based thunderstorm day climatology generally agreed to within 15% of conventional, surface-based thunderstorm day statistics reported for the same period by National Weather Service (NWS) offices located within range of two or more network radars in the State. Poorest agreement between annual totals was found at selected NWS offices in the Greater New York City Metropolitan Area and northward into the lower Hudson River Valley, in far western New York and over far northern New York. Where redundant, near-continuous network radar coverage was available, a northwest-to-southeast increase of thunderstorm days, approaching an annual maximum of 45 in downstate New York was revealed. This gradient in thunderstorm day activity is significantly different from that depicted on isokeraunic maps derived from conventional thunder observing protocol. Because the MDR data are archived on a high-resolution grid of reporting blocks, local thunderstorm maxima on a scale of tens of kilometers may be resolved. Analyses further revealed that 5-25% of all thunderstorm days contained sufficiently vigorous storms to be characterized as `intense'. The greatest frequency of intense thunderstorm days, approaching 8 annually, was located in the highly-populated region of the State along the New York-New Jersey borders, northwest of the Greater New York City Metropolitan Area.

  6. Closed form fourier-based transmit beamforming for MIMO radar

    KAUST Repository

    Lipor, John J.

    2014-05-01

    In multiple-input multiple-output (MIMO) radar setting, it is often desirable to design correlated waveforms such that power is transmitted only to a given set of locations, a process known as beampattern design. To design desired beam-pattern, current research uses iterative algorithms, first to synthesize the waveform covariance matrix, R, then to design the actual waveforms to realize R. In contrast to this, we present a closed form method to design R that exploits discrete Fourier transform and Toeplitz matrix. The resulting covariance matrix fulfills the practical constraints and performance is similar to that of iterative methods. Next, we present a radar architecture for the desired beampattern that does not require the synthesis of covariance matrix nor the design of correlated waveforms. © 2014 IEEE.

  7. Ambiguity Function Analysis for UMTS-Based Passive Multistatic Radar

    Science.gov (United States)

    2014-04-16

    recently, in [15], the authors derived analytical ex- pressions for the monostatic and bistatic ambiguity functions using these UMTS downlink signals...Further, they computed the modified Cramer-Rao lower bound (CRB) for these systems. Conventional passive radar systems operate in a bistatic con...LIMITATION OF ABSTRACT Same as Report ( SAR ) 18. NUMBER OF PAGES 13 19a. NAME OF RESPONSIBLE PERSON a. REPORT unclassified b. ABSTRACT

  8. Mobile Ground-Based Radar Sensor for Localization and Mapping: An Evaluation of two Approaches

    Directory of Open Access Journals (Sweden)

    Damien Vivet

    2013-08-01

    Full Text Available This paper is concerned with robotic applications using a ground‐based radar sensor for simultaneous localization and mapping problems. In mobile robotics, radar technology is interesting because of its long range and the robustness of radar waves to atmospheric conditions, making these sensors well‐suited for extended outdoor robotic applications. Two localization and mapping approaches using data obtained from a 360° field of view microwave radar sensor are presented and compared. The first method is a trajectory‐ oriented simultaneous localization and mapping technique, which makes no landmark assumptions and avoids the data association problem. The estimation of the ego‐motion makes use of the Fourier‐Mellin transform for registering radar images in a sequence, from which the rotation and translation of the sensor motion can be estimated. The second approach uses the consequence of using a rotating range sensor in high speed robotics. In such a situation, movement combinations create distortions in the collected data. Velocimetry is achieved here by explicitly analysing these measurement distortions. As a result, the trajectory of the vehicle and then the radar map of outdoor environments can be obtained. The evaluation of experimental results obtained by the two methods is presented on real‐world data from a vehicle moving at 30 km/h over a 2.5 km course.

  9. Earth-Based Radar Speckle Displacement Interferometry to Study the Spin-Vector of Venus

    Science.gov (United States)

    Holin, I. V.

    2002-01-01

    The spin-vector of Venus was investigated by various Earth- and spacecraft-based techniques but until now no experimental data have been obtained on variations of both in magnitude and direction because of insufficient accuracy and too long measuring interval (much longer than the period of variations). In this work a new on principle ground-based radar interferometric technique named Radar Speckle Displacement Interferometry (RSDI) is proposed to measure precisely instantaneous vector components of and their variations with time. The technique is based on a so called far coherence (speckle displacement) effect for speckled radar fields scattered from randomly rough surfaces of moving objects and aims at precise measurement of their instantaneous rotational- progressive motion parameters.

  10. IMPROVED ALGORITHMS FOR RADAR-BASED RECONSTRUCTION OF ASTEROID SHAPES

    Energy Technology Data Exchange (ETDEWEB)

    Greenberg, Adam H.; Margot, Jean-Luc [University California, Los Angeles, CA (United States)

    2015-10-15

    We describe our implementation of a global-parameter optimizer and Square Root Information Filter into the asteroid-modeling software shape. We compare the performance of our new optimizer with that of the existing sequential optimizer when operating on various forms of simulated data and actual asteroid radar data. In all cases, the new implementation performs substantially better than its predecessor: it converges faster, produces shape models that are more accurate, and solves for spin axis orientations more reliably. We discuss potential future changes to improve shape's fitting speed and accuracy.

  11. THE HIGH RESOLUTION MIMO RADAR SYSTEM BASED ON MINIMIZING THE STATISTICAL COHERENCE OF COMPRESSED SENSING MATRIX

    Institute of Scientific and Technical Information of China (English)

    Zhu Yanping; Song Yaoliang; Chen Jinli; Zhao Delin

    2012-01-01

    Compressed Sensing (CS) theory is a great breakthrough of the traditional Nyquist sampling theory.It can accomplish compressive sampling and signal recovery based on the sparsity of interested signal,the randomness of measurement matrix and nonlinear optimization method of signal recovery.Firstly,the CS principle is reviewed.Then the ambiguity function of Multiple-Input Multiple-Output (MIMO) radar is deduced.After that,combined with CS theory,the ambiguity function of MIMO radar is analyzed and simulated in detail.At last,the resolutions of coherent and non-coherent MIMO radars on the CS theory are discussed.Simulation results show that the coherent MIMO radar has better resolution performance than the non-coherent.But the coherent ambiguity function has higher side lobes,which caused a deterioration in radar target detection performances.The stochastic embattling method of sparse array based on minimizing the statistical coherence of sensing matrix is proposed.And simulation results show that it could effectively suppress side lobes of the ambiguity function and improve the capability of weak target detection.

  12. Experimental Research of HF Passive Radar Based on DRM Digital AM Broadcasting

    Directory of Open Access Journals (Sweden)

    Wan Xian-rong

    2012-03-01

    Full Text Available This paper gives the experimental research of HF Passive Bistatic Radar (HFPBR based on Digital Radio Mondiale (DRM digital AM broadcasting that have been first carried out in China, using the newly-developed all-digital active/passive integrated HF surface wave radar system. The principle, key techniques, experimental equipment, and preliminary results are introduced about this new radar system. Based on analysis of the measurement data, experimental results under different scenarios including surface-wave, sky-wave, and hybrid sky-surface propagation modes are presented, which have proved, for the first time worldwide, the technical feasibility of using DRM broadcasting signal for over-the-horizon detection by field experiment and formed the theoretical and experimental basis for the further development of HFPBR.

  13. Design and Implementation of a FPGA and DSP Based MIMO Radar Imaging System

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2015-06-01

    Full Text Available The work presented in this paper is aimed at the implementation of a real-time multiple-input multiple-output (MIMO imaging radar used for area surveillance. In this radar, the equivalent virtual array method and time-division technique are applied to make 16 virtual elements synthesized from the MIMO antenna array. The chirp signal generater is based on a combination of direct digital synthesizer (DDS and phase locked loop (PLL. A signal conditioning circuit is used to deal with the coupling effect within the array. The signal processing platform is based on an efficient field programmable gates array (FPGA and digital signal processor (DSP pipeline where a robust beamforming imaging algorithm is running on. The radar system was evaluated through a real field experiment. Imaging capability and real-time performance shown in the results demonstrate the practical feasibility of the implementation.

  14. Knitted radar absorbing materials (RAM) based on nickel-cobalt magnetic materials

    Science.gov (United States)

    Teber, Ahmet; Unver, Ibrahim; Kavas, Huseyin; Aktas, Bekir; Bansal, Rajeev

    2016-05-01

    There has been a long-standing interest in the development of flexible, lightweight, thin, and reconfigurable radar absorbing materials (RAM) for military applications such as camouflaging ground-based hardware against airborne radar observation. The use of polymeric Polyacrylonitrile (PAN) fabrics as a host matrix for magnetic metal nano-particles (either at the yarn-stage or after weaving the fabric) for shielding and absorbing applications has been described in the literature. In our experimental investigation, the relative concentrations of Nickel and Cobalt as well as the coating time are varied with a view to optimizing the microwave absorption characteristics of the resulting PAN-based composite material in the radar-frequency bands (X, Ku, and K). It is found that the PAN samples with the shortest coating time have the best return losses (under -20 dB return loss over a moderate bandwidth).

  15. Novel cued search strategy based on information gain for phased array radar

    Institute of Scientific and Technical Information of China (English)

    Lu Jianbin; Hu Weidong; Xiao Hui; Yu Wenxian

    2008-01-01

    A search strategy based on the maximal information gain principle is presented for the cued search of phased array radars. First, the method for the determination of the cued search region, arrangement of beam positions, and the calculation of the prior probability distribution of each beam position is discussed. And then,two search algorithms based on information gain are proposed using Shannon entropy and Kullback-Leibler entropy,respectively. With the proposed strategy, the information gain of each beam position is predicted before the radar detection, and the observation is made in the beam position with the maximal information gain. Compared with the conventional method of sequential search and confirm search, simulation results show that the proposed search strategy can distinctly improve the search performance and save radar time resources with the same given detection probability.

  16. A 24GHz Radar Receiver in CMOS

    NARCIS (Netherlands)

    Kwok, K.C.

    2015-01-01

    This thesis investigates the system design and circuit implementation of a 24GHz-band short-range radar receiver in CMOS technology. The propagation and penetration properties of EM wave offer the possibility of non-contact based remote sensing and through-the-wall imaging of distance stationary or

  17. Use of low power EM radar sensors for speech articulator measurements

    Energy Technology Data Exchange (ETDEWEB)

    Holzrichter, J.F.; Burnett, G.C.

    1997-05-14

    Very low power electromagnetic (EM) wave sensors are being used to measure speech articulator motions such as the vocal fold oscillations, jaw, tongue, and the soft palate. Data on vocal fold motions, that correlate well with established laboratory techniques, as well as data on the jaw, tongue, and soft palate are shown. The vocal fold measurements together with a volume air flow model are being used to perform pitch synchronous estimates of the voiced transfer functions using ARMA (autoregressive moving average) techniques. 6 refs., 5 figs.

  18. Analysis on Target Detection and Classification in LTE Based Passive Forward Scattering Radar

    Directory of Open Access Journals (Sweden)

    Raja Syamsul Azmir Raja Abdullah

    2016-09-01

    Full Text Available The passive bistatic radar (PBR system can utilize the illuminator of opportunity to enhance radar capability. By utilizing the forward scattering technique and procedure into the specific mode of PBR can provide an improvement in target detection and classification. The system is known as passive Forward Scattering Radar (FSR. The passive FSR system can exploit the peculiar advantage of the enhancement in forward scatter radar cross section (FSRCS for target detection. Thus, the aim of this paper is to show the feasibility of passive FSR for moving target detection and classification by experimental analysis and results. The signal source is coming from the latest technology of 4G Long-Term Evolution (LTE base station. A detailed explanation on the passive FSR receiver circuit, the detection scheme and the classification algorithm are given. In addition, the proposed passive FSR circuit employs the self-mixing technique at the receiver; hence the synchronization signal from the transmitter is not required. The experimental results confirm the passive FSR system’s capability for ground target detection and classification. Furthermore, this paper illustrates the first classification result in the passive FSR system. The great potential in the passive FSR system provides a new research area in passive radar that can be used for diverse remote monitoring applications.

  19. Projectile Impact Point Prediction Based on Self-Propelled Artillery Dynamics and Doppler Radar Measurements

    Directory of Open Access Journals (Sweden)

    Mostafa Khalil

    2013-01-01

    Full Text Available Any trajectory calculation method has three primary sources of errors, which are model error, parameter error, and initial state error. In this paper, based on initial projectile flight trajectory data measured using Doppler radar system; a new iterative method is developed to estimate the projectile attitude and the corresponding impact point to improve the second shot hit probability. In order to estimate the projectile initial state, the launch dynamics model of practical 155 mm self-propelled artillery is defined, and hence, the vibration characteristics of the self-propelled artillery is obtained using the transfer matrix method of linear multibody system MSTMM. A discrete time transfer matrix DTTM-4DOF is developed using the modified point mass equations of motion to compute the projectile trajectory and set a direct algebraic relation between any two successive radar data. During iterations, adjustments to the repose angle are made until an agreement with acceptable tolerance occurs between the Doppler radar measurements and the estimated values. Simulated Doppler radar measurements are generated using the nonlinear six-degree-of-freedom trajectory model using the resulted initial disturbance. Results demonstrate that the data estimated using the proposed algorithm agrees well with the simulated Doppler radar data obtained numerically using the nonlinear six-degree-of-freedom model.

  20. Millimeter-wave silicon-based ultra-wideband automotive radar transceivers

    Science.gov (United States)

    Jain, Vipul

    Since the invention of the integrated circuit, the semiconductor industry has revolutionized the world in ways no one had ever anticipated. With the advent of silicon technologies, consumer electronics became light-weight and affordable and paved the way for an Information-Communication-Entertainment age. While silicon almost completely replaced compound semiconductors from these markets, it has been unable to compete in areas with more stringent requirements due to technology limitations. One of these areas is automotive radar sensors, which will enable next-generation collision-warning systems in automobiles. A low-cost implementation is absolutely essential for widespread use of these systems, which leads us to the subject of this dissertation---silicon-based solutions for automotive radars. This dissertation presents architectures and design techniques for mm-wave automotive radar transceivers. Several fully-integrated transceivers and receivers operating at 22-29 GHz and 77-81 GHz are demonstrated in both CMOS and SiGe BiCMOS technologies. Excellent performance is achieved indicating the suitability of silicon technologies for automotive radar sensors. The first CMOS 22-29-GHz pulse-radar receiver front-end for ultra-wideband radars is presented. The chip includes a low noise amplifier, I/Q mixers, quadrature voltage-controlled oscillators, pulse formers and variable-gain amplifiers. Fabricated in 0.18-mum CMOS, the receiver achieves a conversion gain of 35-38.1 dB and a noise figure of 5.5-7.4 dB. Integration of multi-mode multi-band transceivers on a single chip will enable next-generation low-cost automotive radar sensors. Two highly-integrated silicon ICs are designed in a 0.18-mum BiCMOS technology. These designs are also the first reported demonstrations of mm-wave circuits with high-speed digital circuits on the same chip. The first mm-wave dual-band frequency synthesizer and transceiver, operating in the 24-GHz and 77-GHz bands, are demonstrated. All

  1. An Optimal Sorting of Pulse Amplitude Sequence Based on the Phased Array Radar Beam Tasks

    Institute of Scientific and Technical Information of China (English)

    Chuan Sheng∗,Yongshun Zhang; Wenlong Lu

    2016-01-01

    The study of phased array radar ( PAR) pulse amplitude sequence characteristics is the key to understand the radar’s working state and its beam’s scanning manner. According to the principle of antenna pattern formation and the searching and tracking modes of beams, this paper analyzes the characteristics and differences of pulse amplitude sequence when the radar beams work in searching and tracking modes respectively. Then an optimal sorting model of pulse amplitude sequence is established based on least⁃squares and curve⁃fitting methods. This method is helpful for acquiring the current working state of the radar and recognizing its instantaneous beam pointing by sorting the pulse amplitude sequence without the necessity to estimate the antenna pattern.

  2. ECCM schemes in netted radar system based on temporal pulse diversity

    Institute of Scientific and Technical Information of China (English)

    Ahmed Abdalla; Zhao Yuan; Bin Tang

    2016-01-01

    For a netted radar system to counteract the deception electronic countermeasure (ECM) signals, an effective electronic counter countermeasure (ECCM) approach is proposed. The pro-posed approach is realized based on the new signaling strategy for the temporal pulse diversity, which makes use of transmitting pulses at each pulse repetition interval (PRI) with specific trans-mission pulse block, and then fol owing proper processing and information fusion. The existence of the deceptive ECM signal is confirmed by one station, while the other stations in the netted radar with same parameters applied the pulse diversity skil ful y. Meanwhile, this method ensured that, pulse diversity can be ap-plied in netted radar. The performance assessment shows that the proposed solutions are effective in presence of ECM signals. This algorithm has been demonstrated by simulations. The presented simulation results are in excel ent consensus with theoretical pre-dictions.

  3. Backscatter Transponder Based on Frequency Selective Surface for FMCW Radar Applications

    Directory of Open Access Journals (Sweden)

    A.Lazaro

    2014-06-01

    Full Text Available This paper describes an actively-controlled frequency selective surface (FSS to implement a backscatter transponder. The FSS is composed by dipoles loaded with switching PIN diodes. The transponder exploits the change in the radar cross section (RCS of the FSS with the bias of the diodes to modulate the backscattered response of the tag to the FMCW radar. The basic operation theory of the system is explained here. An experimental setup based on a commercial X-band FMCW radar working as a reader is proposed to measure the transponders. The transponder response can be distinguished from the interference of non-modulated clutter, modulating the transponder’s RCS. Some FSS with different number of dipoles are studied, as a proof of concept. Experimental results at several distances are provided.

  4. FPGA based hardware optimized implementation of signal processing system for LFM pulsed radar

    Science.gov (United States)

    Azim, Noor ul; Jun, Wang

    2016-11-01

    Signal processing is one of the main parts of any radar system. Different signal processing algorithms are used to extract information about different parameters like range, speed, direction etc, of a target in the field of radar communication. This paper presents LFM (Linear Frequency Modulation) pulsed radar signal processing algorithms which are used to improve target detection, range resolution and to estimate the speed of a target. Firstly, these algorithms are simulated in MATLAB to verify the concept and theory. After the conceptual verification in MATLAB, the simulation is converted into implementation on hardware using Xilinx FPGA. Chosen FPGA is Xilinx Virtex-6 (XC6LVX75T). For hardware implementation pipeline optimization is adopted and also other factors are considered for resources optimization in the process of implementation. Focusing algorithms in this work for improving target detection, range resolution and speed estimation are hardware optimized fast convolution processing based pulse compression and pulse Doppler processing.

  5. SCENARIO AND TARGET SIMULATION FOR A GROUND BASED MULTIFUNCTION PHASED ARRAY RADAR

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This paper describes a scenario and target simulation which operates in non real-time to provide full closed-loop operation of the ground based multifunction phased array radar simulation system in support of ballistic missile defence experiments against countermeasure.By simulating the target scattering signature and dynamical signature,this scenario and target simulation provide re- alistic scenario source to evaluate the system performance of multifunction phased array radar,and the key algorithms verification and validation such as target tracking,multi-target imaging and target recognition.

  6. Assessment of crop damage and hail risk based on radar hail signature information

    Science.gov (United States)

    Tani, Satyanarayana; Paulitsch, Helmut; Teschl, Reinhard; Süsser-Rechberger, Barbara

    2016-04-01

    Hail storm damage is a major concern to the farmers in the province of Styria, Austria. Each year severe hail storms are causing damages to crops, resulting in losses of millions of euros. High spatiotemporal resolution data are essential to properly assess crop damage information for the insurance sector and also for the better risk assessment. Radar data offer high spatial and temporal resolutions, resulting in very promising option for crop damage assessment and hail risk analysis. This study focuses on the combined analysis of hail signature information from radar and ground measurements for crop hail damage assessment. The days with the high crop hail damage claims were selected for the investigation. Total 16 hail days were assigned to examine the relation between radar-derived products and damages produced by hail in Styria during 2015. 3D single polarization C-band weather radar data and radiosonde freezing level data were used to derive hail kinetic energy flux as well as flux integrated over the whole event. Hail events from ESWD (European Severe Weather Database) and crop damage reports from the Austrian Hail Insurance System were allotted for validation. The spatial distribution maps of total hail kinetic energy were developed to capture the swath and intensity of the hail storms to identify potential hail damage areas. The results show that in most cases radar-based hail signature information well corresponds to the areas where hail events and damage footprints were reported. The radar-based hail signature information is a useful detection option for the assessment of crop damage and hail risk.

  7. Development of wide band digital receiver for atmospheric radars using COTS board based SDR

    Science.gov (United States)

    Yasodha, Polisetti; Jayaraman, Achuthan; Thriveni, A.

    2016-07-01

    Digital receiver extracts the received echo signal information, and is a potential subsystem for atmospheric radar, also referred to as wind profiling radar (WPR), which provides the vertical profiles of 3-dimensional wind vector in the atmosphere. This paper presents the development of digital receiver using COTS board based Software Defined Radio technique, which can be used for atmospheric radars. The developmental work is being carried out at National Atmospheric Research Laboratory (NARL), Gadanki. The digital receiver consists of a commercially available software defined radio (SDR) board called as universal software radio peripheral B210 (USRP B210) and a personal computer. USRP B210 operates over a wider frequency range from 70 MHz to 6 GHz and hence can be used for variety of radars like Doppler weather radars operating in S/C bands, in addition to wind profiling radars operating in VHF, UHF and L bands. Due to the flexibility and re-configurability of SDR, where the component functionalities are implemented in software, it is easy to modify the software to receive the echoes and process them as per the requirement suitable for the type of the radar intended. Hence, USRP B210 board along with the computer forms a versatile digital receiver from 70 MHz to 6 GHz. It has an inbuilt direct conversion transceiver with two transmit and two receive channels, which can be operated in fully coherent 2x2 MIMO fashion and thus it can be used as a two channel receiver. Multiple USRP B210 boards can be synchronized using the pulse per second (PPS) input provided on the board, to configure multi-channel digital receiver system. RF gain of the transceiver can be varied from 0 to 70 dB. The board can be controlled from the computer via USB 3.0 interface through USRP hardware driver (UHD), which is an open source cross platform driver. The USRP B210 board is connected to the personal computer through USB 3.0. Reference (10 MHz) clock signal from the radar master oscillator

  8. Radar illusion via metamaterials

    Science.gov (United States)

    Jiang, Wei Xiang; Cui, Tie Jun

    2011-02-01

    An optical illusion is an image of a real target perceived by the eye that is deceptive or misleading due to a physiological illusion or a specific visual trick. The recently developed metamaterials provide efficient approaches to generate a perfect optical illusion. However, all existing research on metamaterial illusions has been limited to theory and numerical simulations. Here, we propose the concept of a radar illusion, which can make the electromagnetic (EM) image of a target gathered by radar look like a different target, and we realize a radar illusion device experimentally to change the radar image of a metallic target into a dielectric target with predesigned size and material parameters. It is well known that the radar signatures of metallic and dielectric objects are significantly different. However, when a metallic target is enclosed by the proposed illusion device, its EM scattering characteristics will be identical to that of a predesigned dielectric object under the illumination of radar waves. Such an illusion device will confuse the radar, and hence the real EM properties of the metallic target cannot be perceived. We designed and fabricated the radar illusion device using artificial metamaterials in the microwave frequency, and good illusion performances are observed in the experimental results.

  9. Improved OAM-Based Radar Targets Detection Using Uniform Concentric Circular Arrays

    Directory of Open Access Journals (Sweden)

    Mingtuan Lin

    2016-01-01

    Full Text Available Without any relative moves or beam scanning, the novel Orbital-Angular-Momentum- (OAM- based radar targets detection technique using uniform concentric circular arrays (UCCAs shows the azimuthal estimation ability, which provides new perspective for radar system design. However, the main estimation method, that is, Fast Fourier Transform (FFT, under this scheme suffers from low resolution. As a solution, this paper rebuilds the OAM-based radar targets detection model and introduces the multiple signal classification (MUSIC algorithm to improve the resolution for detecting targets within the main lobes. The spatial smoothing technique is proposed to tackle the coherent problem brought by the proposed model. Analytical study and simulation demonstrate the superresolution estimation capacity the MUSIC algorithm can achieve for detecting targets within the main lobes. The performance of the MUSIC algorithm to detect targets not illuminated by the main lobes is further evaluated. Despite the fact that MUSIC algorithm loses the resolution advantage under this case, its estimation is more robust than that of the FFT method. Overall, the proposed MUSIC algorithm for the OAM-based radar system demonstrates the superresolution ability for detecting targets within the main lobes and good robustness for targets out of the main lobes.

  10. An Overview on Development of Passive Radar Based on the Low Frequency Band Digital Broadcasting and TV Signals

    Directory of Open Access Journals (Sweden)

    Wan Xian-rong

    2012-06-01

    Full Text Available Starting from the detection principle and characteristics of passive radar, this paper describes the development of passive radar based on the low frequency band (HF/VHF/UHF digital broadcasting and TV signal. Based on the radio coverage ratio and technical features of digital broadcasting and TV signals, the research status in abroad, especially in Europe, is introduced at first, on experimental systems, technical parameters, and comparative experiments. Then the latest development of passive radars, in different frequency bands in China, both theory and experimental study are presented. Followed is the commentary on the key techniques and problems of Digital Broadcasting-based Passive Radar (DBPR, including the waveform’s properties and its modification, reference signal extraction, multipath clutter rejection, target detection, tracking, and fusion as well as real-time signal processing. Finally, the prospects of development and application of this kind of passive radar are discussed.

  11. Synthetic aperture radar autofocus based on a bilinear model.

    Science.gov (United States)

    Liu, Kuang-Hung; Wiesel, Ami; Munson, David C

    2012-05-01

    Autofocus algorithms are used to restore images in nonideal synthetic aperture radar imaging systems. In this paper, we propose a bilinear parametric model for the unknown image and the nuisance phase parameters and derive an efficient maximum-likelihood autofocus (MLA) algorithm. In the special case of a simple image model and a narrow range of look angles, MLA coincides with the successful multichannel autofocus (MCA). MLA can be interpreted as a generalization of MCA to a larger class of models with a larger range of look angles. We analyze its advantages over previous extensions of MCA in terms of identifiability conditions and noise sensitivity. As a byproduct, we also propose numerical approximations to the difficult constant modulus quadratic program that lies at the core of these algorithms. We demonstrate the superior performance of our proposed methods using computer simulations in both the correct and mismatched system models. MLA performs better than other methods, both in terms of the mean squared error and visual quality of the restored image.

  12. Fourier-Based Transmit Beampattern Design Using MIMO Radar

    KAUST Repository

    Lipor, John

    2014-05-01

    In multiple-input multiple-output (MIMO) radar settings, it is often desirable to transmit power only to a given location or set of locations defined by a beampattern. Transmit waveform design is a topic that has received much attention recently, involving synthesis of both the signal covariance matrix,, as well as the actual waveforms. Current methods involve a two-step process of designing via iterative solutions and then using to generate waveforms that fulfill practical constraints such as having a constant-envelope or drawing from a finite alphabet. In this paper, a closed-form method to design for a uniform linear array is proposed that utilizes the discrete Fourier transform (DFT) coefficients and Toeplitz matrices. The resulting covariance matrix fulfills the practical constraints such as positive semidefiniteness and the uniformelemental power constraint and provides performance similar to that of iterative methods, which require a much greater computation time. Next, a transmit architecture is presented that exploits the orthogonality of frequencies at discrete DFT values to transmit a sum of orthogonal signals from each antenna. The resulting waveforms provide a lower mean-square error than current methods at a much lower computational cost, and a simulated detection scenario demonstrates the performance advantages achieved.

  13. Short-Range Vital Signs Sensing Based on EEMD and CWT Using IR-UWB Radar.

    Science.gov (United States)

    Hu, Xikun; Jin, Tian

    2016-11-30

    The radar sensor described realizes healthcare monitoring capable of detecting subject chest-wall movement caused by cardiopulmonary activities and wirelessly estimating the respiration and heartbeat rates of the subject without attaching any devices to the body. Conventional single-tone Doppler radar can only capture Doppler signatures because of a lack of bandwidth information with noncontact sensors. In contrast, we take full advantage of impulse radio ultra-wideband (IR-UWB) radar to achieve low power consumption and convenient portability, with a flexible detection range and desirable accuracy. A noise reduction method based on improved ensemble empirical mode decomposition (EEMD) and a vital sign separation method based on the continuous-wavelet transform (CWT) are proposed jointly to improve the signal-to-noise ratio (SNR) in order to acquire accurate respiration and heartbeat rates. Experimental results illustrate that respiration and heartbeat signals can be extracted accurately under different conditions. This noncontact healthcare sensor system proves the commercial feasibility and considerable accessibility of using compact IR-UWB radar for emerging biomedical applications.

  14. Short-Range Vital Signs Sensing Based on EEMD and CWT Using IR-UWB Radar

    Directory of Open Access Journals (Sweden)

    Xikun Hu

    2016-11-01

    Full Text Available The radar sensor described realizes healthcare monitoring capable of detecting subject chest-wall movement caused by cardiopulmonary activities and wirelessly estimating the respiration and heartbeat rates of the subject without attaching any devices to the body. Conventional single-tone Doppler radar can only capture Doppler signatures because of a lack of bandwidth information with noncontact sensors. In contrast, we take full advantage of impulse radio ultra-wideband (IR-UWB radar to achieve low power consumption and convenient portability, with a flexible detection range and desirable accuracy. A noise reduction method based on improved ensemble empirical mode decomposition (EEMD and a vital sign separation method based on the continuous-wavelet transform (CWT are proposed jointly to improve the signal-to-noise ratio (SNR in order to acquire accurate respiration and heartbeat rates. Experimental results illustrate that respiration and heartbeat signals can be extracted accurately under different conditions. This noncontact healthcare sensor system proves the commercial feasibility and considerable accessibility of using compact IR-UWB radar for emerging biomedical applications.

  15. A simulation-based approach towards automatic target recognition of high resolution space borne radar signatures

    Science.gov (United States)

    Anglberger, H.; Kempf, T.

    2016-10-01

    Specific imaging effects that are caused mainly by the range measurement principle of a radar device, its much lower frequency range as compared to the optical spectrum, the slanted imaging geometry and certainly the limited spatial resolution complicates the interpretation of radar signatures decisively. Especially the coherent image formation which causes unwanted speckle noise aggravates the problem of visually recognizing target objects. Fully automatic approaches with acceptable false alarm rates are therefore an even harder challenge. At the Microwaves and Radar Institute of the German Aerospace Center (DLR) the development of methods to implement a robust overall processing workflow for automatic target recognition (ATR) out of high resolution synthetic aperture radar (SAR) image data is under progress. The heart of the general approach is to use time series exploitation for the former detection step and simulation-based signature matching for the subsequent recognition. This paper will show the overall ATR chain as a proof of concept for the special case of airplane recognition on image data from the space borne SAR sensor TerraSAR-X.

  16. Analysis of Human's Motions Based on Local Mean Decomposition in Through-wall Radar Detection

    Science.gov (United States)

    Lu, Qi; Liu, Cai; Zeng, Zhaofa; Li, Jing; Zhang, Xuebing

    2016-04-01

    Observation of human motions through a wall is an important issue in security applications and search-and rescue. Radar has advantages in looking through walls where other sensors give low performance or cannot be used at all. Ultrawideband (UWB) radar has high spatial resolution as a result of employment of ultranarrow pulses. It has abilities to distinguish the closely positioned targets and provide time-lapse information of targets. Moreover, the UWB radar shows good performance in wall penetration when the inherently short pulses spread their energy over a broad frequency range. Human's motions show periodic features including respiration, swing arms and legs, fluctuations of the torso. Detection of human targets is based on the fact that there is always periodic motion due to breathing or other body movements like walking. The radar can gain the reflections from each human body parts and add the reflections at each time sample. The periodic movements will cause micro-Doppler modulation in the reflected radar signals. Time-frequency analysis methods are consider as the effective tools to analysis and extract micro-Doppler effects caused by the periodic movements in the reflected radar signal, such as short-time Fourier transform (STFT), wavelet transform (WT), and Hilbert-Huang transform (HHT).The local mean decomposition (LMD), initially developed by Smith (2005), is to decomposed amplitude and frequency modulated signals into a small set of product functions (PFs), each of which is the product of an envelope signal and a frequency modulated signal from which a time-vary instantaneous phase and instantaneous frequency can be derived. As bypassing the Hilbert transform, the LMD has no demodulation error coming from window effect and involves no negative frequency without physical sense. Also, the instantaneous attributes obtained by LMD are more stable and precise than those obtained by the empirical mode decomposition (EMD) because LMD uses smoothed local

  17. Direction synthesis in DOA estimation for monostatic multiple input multiple output(MIMO) radar based on synthetic impulse and aperture radar (SIAR) and its performance analysis

    Institute of Scientific and Technical Information of China (English)

    ZHAO GuangHui; CHEN BaiXiao; ZHU ShouPing

    2008-01-01

    A new direction synthetic method for monostatic multiple input multiple output (MIMO) radar is presented based on synthetic impulse and aperture radar (SIAR) system. Concerned with the monostatic MIMO radar which simultaneously emits orthogonal signals with multi-carrier-frequency and possesses sparsely distributed transmitting and receiving arrays with respective location, as well as the situation for the presence of multipath propagation in the low flying target's echo, the method integrates the aperture of the transmitting arrays with the receiving arrays to form the digital beam-forming (DBF) in azimuth and elevation dimensions. And a study has been made of planar general MUSIC algorithm based on decorrelating the multipath signals of multi-carrier-frequency MIMO radar. Through compensat-ing the phase delay of both the transmitting and the receiving arrays and synthe-sizing the transmitting beam in two dimensions at the receiver, the angular resolu-tion and measurement accuracy are improved and the computational complexity is reduced after transforming the three-dimensional (3D) parameter estimation prob-lem into a two-dimensional (2D) one. Finally, the Cramer-Rao Bounds (CRBs) of DOA estimation for azimuth and elevation is put forward with the exsitJng multipath propagation. Results of computer simulation demonstrate the validity of the new method.

  18. Direction synthesis in DOA estimation for monostatic multiple input multiple output (MIMO) radar based on synthetic impulse and aperture radar (SIAR) and its performance analysis

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A new direction synthetic method for monostatic multiple input multiple output (MIMO) radar is presented based on synthetic impulse and aperture radar (SIAR) system. Concerned with the monostatic MIMO radar which simultaneously emits orthogonal signals with multi-carrier-frequency and possesses sparsely distributed transmitting and receiving arrays with respective location, as well as the situation for the presence of multipath propagation in the low flying target’s echo, the method integrates the aperture of the transmitting arrays with the receiving arrays to form the digital beam-forming (DBF) in azimuth and elevation dimensions. And a study has been made of planar general MUSIC algorithm based on decorrelating the multipath signals of multi-carrier-frequency MIMO radar. Through compensat-ing the phase delay of both the transmitting and the receiving arrays and synthe-sizing the transmitting beam in two dimensions at the receiver, the angular resolu-tion and measurement accuracy are improved and the computational complexity is reduced after transforming the three-dimensional (3D) parameter estimation prob-lem into a two-dimensional (2D) one. Finally, the Cramer-Rao Bounds (CRBs) of DOA estimation for azimuth and elevation is put forward with the exsiting multipath propagation. Results of computer simulation demonstrate the validity of the new method.

  19. Evaluating the potential of radar-based rainfall estimates for streamflow and flood simulations in the Philippines

    Directory of Open Access Journals (Sweden)

    Catherine Cristobal Abon

    2016-07-01

    Full Text Available This case study evaluates the suitability of radar-based quantitative precipitation estimates (QPEs for the simulation of streamflow in the Marikina River Basin (MRB, the Philippines. Hourly radar-based QPEs were produced from reflectivity that had been observed by an S-band radar located about 90 km from the MRB. Radar data processing and precipitation estimation were carried out using the open source library wradlib. To assess the added value of the radar-based QPE, we used spatially interpolated rain gauge observations (gauge-only (GO product as a benchmark. Rain gauge observations were also used to quantify rainfall estimation errors at the point scale. At the point scale, the radar-based QPE outperformed the GO product in 2012, while for 2013, the performance was similar. For both periods, estimation errors substantially increased from daily to the hourly accumulation intervals. Despite this fact, both rainfall estimation methods allowed for a good representation of observed streamflow when used to force a hydrological simulation model of the MRB. Furthermore, the results of the hydrological simulation were consistent with rainfall verification at the point scale: the radar-based QPE performed better than the GO product in 2012, and equivalently in 2013. Altogether, we could demonstrate that, in terms of streamflow simulation, the radar-based QPE can perform as good as or even better than the GO product – even for a basin such as the MRB which has a comparatively dense rain gauge network. This suggests good prospects for using radar-based QPE to simulate and forecast streamflow in other parts of the Philippines where rain gauge networks are not as dense.

  20. Multi-Frequency Target Detection Techniques for DVB-T Based Passive Radar Sensors

    Directory of Open Access Journals (Sweden)

    Tatiana Martelli

    2016-09-01

    Full Text Available This paper investigates the possibility to improve target detection capability in a DVB-T- based passive radar sensor by jointly exploiting multiple digital television channels broadcast by the same transmitter of opportunity. Based on the remarkable results obtained by such a multi-frequency approach using other signals of opportunity (i.e., FM radio broadcast transmissions, we propose appropriate modifications to the previously devised signal processing techniques for them to be effective in the newly considered scenarios. The resulting processing schemes are extensively applied against experimental DVB-T-based passive radar data pertaining to different surveillance applications. The obtained results clearly show the effectiveness of the proposed multi-frequency approaches and demonstrate their suitability for application in the considered scenarios.

  1. Evaluation of Radar Vegetation Indices for Vegetation Water Content Estimation Using Data from a Ground-Based SMAP Simulator

    Science.gov (United States)

    Srivastava, Prashant K.; O'Neill, Peggy; Cosh, Michael; Lang, Roger; Joseph, Alicia

    2015-01-01

    Vegetation water content (VWC) is an important component of microwave soil moisture retrieval algorithms. This paper aims to estimate VWC using L band active and passive radar/radiometer datasets obtained from a NASA ground-based Soil Moisture Active Passive (SMAP) simulator known as ComRAD (Combined Radar/Radiometer). Several approaches to derive vegetation information from radar and radiometer data such as HH, HV, VV, Microwave Polarization Difference Index (MPDI), HH/VV ratio, HV/(HH+VV), HV/(HH+HV+VV) and Radar Vegetation Index (RVI) are tested for VWC estimation through a generalized linear model (GLM). The overall analysis indicates that HV radar backscattering could be used for VWC content estimation with highest performance followed by HH, VV, MPDI, RVI, and other ratios.

  2. Polarimetric Analysis of the Interference from Base Stations to UHF-band Radar

    Directory of Open Access Journals (Sweden)

    Ren Bo

    2016-04-01

    Full Text Available Radar detection and tracking performance in the UHF-band can be influenced by the downlink signals of communication base stations. The polarimetric properties of interference from base stations are measured and analyzed as a basis for suppressing this type of interference by a polarization processing method. In this study, we establish signal models from the base station for dual-polarization UHF-band radar. We express the Probability Density Functions (PDF of the estimated polarization ratio and degree of polarization in a closed form and use them to describe the statistical properties of the interference environment. We developed polarimetric radar reception experiments for the signals from both Single-Base Stations (SBS and Multi-Base Stations (MBS. Experimental results proved that deterministic polarized descriptions are appropriate only for signals from SBS but not from MBS or from stations with a low DoP (Degree of Polarization. However, the proposed statistical method can be used to describe both SBS and MBS cases, which we demonstrated by comparing the theoretical models with real measurement data.

  3. An operational weather radar-based Quantitative Precipitation Estimation and its application in catchment water resources modeling

    DEFF Research Database (Denmark)

    He, Xin; Vejen, Flemming; Stisen, Simon

    2011-01-01

    of precipitation compared with rain-gauge-based methods, thus providing the basis for better water resources assessments. The radar QPE algorithm called ARNE is a distance-dependent areal estimation method that merges radar data with ground surface observations. The method was applied to the Skjern River catchment...... reliable simulations of stream flow and water balance. The potential of using radar-based precipitation was found to be especially high at a smaller scale, where the impact of spatial resolution was evident from the stream discharge results. Also, groundwater recharge was shown to be sensitive...

  4. Construction of Polarimetric Radar-Based Reference Rain Maps for the Iowa Flood Studies Campaign

    Science.gov (United States)

    Petersen, Walt; Krajewski, Witek; Wolff, David; Gatlin, Patrick

    2015-04-01

    The Global Precipitation Measurement (GPM) Mission Iowa Flood Studies (IFloodS) campaign was conducted in central and northeastern Iowa during the months of April-June, 2013. Specific science objectives for IFloodS included quantification of uncertainties in satellite and ground-based estimates of precipitation, 4-D characterization of precipitation physical processes and associated parameters (e.g., size distributions, water contents, types, structure etc.), assessment of the impact of precipitation estimation uncertainty and physical processes on hydrologic predictive skill, and refinement of field observations and data analysis approaches as they pertain to future GPM integrated hydrologic validation and related field studies. In addition to field campaign archival of raw and processed satellite data (including precipitation products), key ground-based platforms such as the NASA NPOL S-band and D3R Ka/Ku-band dual-polarimetric radars, University of Iowa X-band dual-polarimetric radars, a large network of paired rain gauge platforms, and a large network of 2D Video and Parsivel disdrometers were deployed. In something of a canonical approach, the radar (NPOL in particular), gauge and disdrometer observational assets were deployed to create a consistent high-quality distributed (time and space sampling) radar-based ground "reference" rainfall dataset, with known uncertainties, that could be used for assessing the satellite-based precipitation products at a range of space/time scales. Subsequently, the impact of uncertainties in the satellite products could be evaluated relative to the ground-benchmark in coupled weather, land-surface and distributed hydrologic modeling frameworks as related to flood prediction. Relative to establishing the ground-based "benchmark", numerous avenues were pursued in the making and verification of IFloodS "reference" dual-polarimetric radar-based rain maps, and this study documents the process and results as they pertain specifically

  5. Detection-Discrimination Method for Multiple Repeater False Targets Based on Radar Polarization Echoes

    Directory of Open Access Journals (Sweden)

    Z. W. ZONG

    2014-04-01

    Full Text Available Multiple repeat false targets (RFTs, created by the digital radio frequency memory (DRFM system of jammer, are widely used in practical to effectively exhaust the limited tracking and discrimination resource of defence radar. In this paper, common characteristic of radar polarization echoes of multiple RFTs is used for target recognition. Based on the echoes from two receiving polarization channels, the instantaneous polarization radio (IPR is defined and its variance is derived by employing Taylor series expansion. A detection-discrimination method is designed based on probability grids. By using the data from microwave anechoic chamber, the detection threshold of the method is confirmed. Theoretical analysis and simulations indicate that the method is valid and feasible. Furthermore, the estimation performance of IPRs of RFTs due to the influence of signal noise ratio (SNR is also covered.

  6. Ambiguity Function Analysis and Processing for Passive Radar Based on CDR Digital Audio Broadcasting

    Directory of Open Access Journals (Sweden)

    Zhang Qiang

    2015-01-01

    Full Text Available China Digital Radio (CDR broadcasting is a new standard of digital audio broadcasting of FM frequency (87–108 MHz based on our research and development efforts. It is compatible with the frequency spectrum in analog FM radio and satisfies the requirements for smooth transition from analog to digital signal in FM broadcasting in China. This paper focuses on the signal characteristics and processing methods of radio-based passive radar. The signal characteristics and ambiguity function of a passive radar illumination source are analyzed. The adverse effects on the target detection of the side peaks owing to cyclic prefix, the Doppler ambiguity strips because of signal synchronization, and the range of side peaks resulting from the signal discontinuous spectrum are then studied. Finally, methods for suppressing these side peaks are proposed and their effectiveness is verified by simulations.

  7. Construction of Polarimetric Radar-Based Reference Rain Maps for the Iowa Flood Studies Campaign

    Science.gov (United States)

    Petersen, Walter; Wolff, David; Krajewski, Witek; Gatlin, Patrick

    2015-01-01

    The Global Precipitation Measurement (GPM) Mission Iowa Flood Studies (IFloodS) campaign was conducted in central and northeastern Iowa during the months of April-June, 2013. Specific science objectives for IFloodS included quantification of uncertainties in satellite and ground-based estimates of precipitation, 4-D characterization of precipitation physical processes and associated parameters (e.g., size distributions, water contents, types, structure etc.), assessment of the impact of precipitation estimation uncertainty and physical processes on hydrologic predictive skill, and refinement of field observations and data analysis approaches as they pertain to future GPM integrated hydrologic validation and related field studies. In addition to field campaign archival of raw and processed satellite data (including precipitation products), key ground-based platforms such as the NASA NPOL S-band and D3R Ka/Ku-band dual-polarimetric radars, University of Iowa X-band dual-polarimetric radars, a large network of paired rain gauge platforms, and a large network of 2D Video and Parsivel disdrometers were deployed. In something of a canonical approach, the radar (NPOL in particular), gauge and disdrometer observational assets were deployed to create a consistent high-quality distributed (time and space sampling) radar-based ground "reference" rainfall dataset, with known uncertainties, that could be used for assessing the satellite-based precipitation products at a range of space/time scales. Subsequently, the impact of uncertainties in the satellite products could be evaluated relative to the ground-benchmark in coupled weather, land-surface and distributed hydrologic modeling frameworks as related to flood prediction. Relative to establishing the ground-based "benchmark", numerous avenues were pursued in the making and verification of IFloodS "reference" dual-polarimetric radar-based rain maps, and this study documents the process and results as they pertain specifically

  8. Aspects of Applying Weather Radar Based Nowcast for Highways in Denmark

    DEFF Research Database (Denmark)

    Rasmussen, Michael R.; Quist, MIchael; Thorndahl, Søren Liedtke

    The Danish road network consists of 73.331 km. of roads. 3.790 km. of these roads are state roads and are considered as major lines of transportation. Although these roads only represent 5% of the total network, 45% of all traffic is moving along these roads. Application of weather radar based...... scenarios. The first is often related to extreme rain intensities while the second can also include less extreme intensities (but maybe higher volume). In both the case of deteriorated traffic conditions and construction phase, a nowcast based on weather radar can provide valuable information...... on the visibility, rain intensity and rain volume. This can actively be used to optimise basin volumes and to direct critical information to traffic. A system for nowcast dedicated to road applications are under development in Denmark. This paper investigates the different approaches in nowcasting of precipitation...

  9. Passive Radar based on WiFi transmissions: signal processing schemes and experimental results

    OpenAIRE

    Falcone, Paolo

    2013-01-01

    Aim of this work is to study innovative techniques and processing strategies for a new passive sensor for short range surveillance. The principle of work of the sensor will be based on the passive radar principle, and WiFi transmissions - which usually provide Internet access within local areas - will be exploited by the passive sensor to detect, localize and classify targets. EU ATOM Project (FP7)

  10. Wavelet Transform of Super-Resolutions Based on Radar and Infrared Sensor Fusion

    Science.gov (United States)

    1998-05-01

    0I Q’UAL1 INwPO¶= I VI STATEMB r AApproved for public release; Distribution Unlimited NAVY CASE 77545 WAVELET TRANSFORM OF SUPER-RESOLUTIONS BASED ON...INVENTION It is, therefore, an object of the present invention to provide a structure and method for applying the forward and reverse Wavelet Transform (WT...invention, the noisy super- 10 resolution of infrared imaging is combined with the Wavelet transform for radar corner back-scattering size information

  11. A radar-based hydrological model for flash flood prediction in the dry regions of Israel

    Science.gov (United States)

    Ronen, Alon; Peleg, Nadav; Morin, Efrat

    2014-05-01

    Flash floods are floods which follow shortly after rainfall events, and are among the most destructive natural disasters that strike people and infrastructures in humid and arid regions alike. Using a hydrological model for the prediction of flash floods in gauged and ungauged basins can help mitigate the risk and damage they cause. The sparsity of rain gauges in arid regions requires the use of radar measurements in order to get reliable quantitative precipitation estimations (QPE). While many hydrological models use radar data, only a handful do so in dry climate. This research presents a robust radar-based hydro-meteorological model built specifically for dry climate. Using this model we examine the governing factors of flash floods in the arid and semi-arid regions of Israel in particular and in dry regions in general. The hydrological model built is a semi-distributed, physically-based model, which represents the main hydrological processes in the area, namely infiltration, flow routing and transmission losses. Three infiltration functions were examined - Initial & Constant, SCS-CN and Green&Ampt. The parameters for each function were found by calibration based on 53 flood events in three catchments, and validation was performed using 55 flood events in six catchments. QPE were obtained from a C-band weather radar and adjusted using a weighted multiple regression method based on a rain gauge network. Antecedent moisture conditions were calculated using a daily recharge assessment model (DREAM). We found that the SCS-CN infiltration function performed better than the other two, with reasonable agreement between calculated and measured peak discharge. Effects of storm characteristics were studied using synthetic storms from a high resolution weather generator (HiReS-WG), and showed a strong correlation between storm speed, storm direction and rain depth over desert soils to flood volume and peak discharge.

  12. Space Fence Ground-Based Radar System Increment 1 (Space Fence Inc 1)

    Science.gov (United States)

    2015-12-01

    Selected Acquisition Report (SAR) RCS: DD-A&T(Q&A)823-438 Space Fence Ground-Based Radar System Increment 1 (Space Fence Inc 1) As of FY 2017...11 Track to Budget 17 Cost and Funding 18 Low Rate Initial Production 23 Foreign Military Sales 24 Nuclear Costs 24 Unit Cost...Document CLIN - Contract Line Item Number CPD - Capability Production Document CY - Calendar Year DAB - Defense Acquisition Board DAE - Defense Acquisition

  13. Embedded DSP-based telehealth radar system for remote in-door fall detection.

    Science.gov (United States)

    Garripoli, Carmine; Mercuri, Marco; Karsmakers, Peter; Jack Soh, Ping; Crupi, Giovanni; Vandenbosch, Guy A E; Pace, Calogero; Leroux, Paul; Schreurs, Dominique

    2015-01-01

    Telehealth systems and applications are extensively investigated nowadays to enhance the quality-of-care and, in particular, to detect emergency situations and to monitor the well-being of elderly people, allowing them to stay at home independently as long as possible. In this paper, an embedded telehealth system for continuous, automatic, and remote monitoring of real-time fall emergencies is presented and discussed. The system, consisting of a radar sensor and base station, represents a cost-effective and efficient healthcare solution. The implementation of the fall detection data processing technique, based on the least-square support vector machines, through a digital signal processor and the management of the communication between radar sensor and base station are detailed. Experimental tests, for a total of 65 mimicked fall incidents, recorded with 16 human subjects (14 men and two women) that have been monitored for 320 min, have been used to validate the proposed system under real circumstances. The subjects' weight is between 55 and 90 kg with heights between 1.65 and 1.82 m, while their age is between 25 and 39 years. The experimental results have shown a sensitivity to detect the fall events in real time of 100% without reporting false positives. The tests have been performed in an area where the radar's operation was not limited by practical situations, namely, signal power, coverage of the antennas, and presence of obstacles between the subject and the antennas.

  14. Linearity enhancement of TVGA based on adaptive sweep optimisation in monostatic radar receiver

    Science.gov (United States)

    Almslmany, Amir; Wang, Caiyun; Cao, Qunsheng

    2016-08-01

    The limited input dynamic power range of the radar receiver and the power loss due to the targets' ranges are two potential problems in the radar receivers. This paper proposes a model based on the time-varying gain amplifier (TVGA) to compensate the power loss from the targets' ranges, and using the negative impedance compensation technique to enhance the TVGA linearity based on Volterra series. The simulation has been done based on adaptive sweep optimisation (ASO) using advanced design system (ADS) and Matlab. It shows that the suppression of the third-order intermodulation products (IMR3) was carried out for two-tone test, the high-gain accuracy improved by 3 dB, and the high linearity IMR3 improved by 14 dB. The monostatic radar system was tested to detect three targets at different ranges and to compare its probability of detection with the prior models; the results show that the probability of detection has been increased for ASO/TVGA.

  15. Cramer-Rao Lower Bound Evaluation for Linear Frequency Modulation Based Active Radar Networks Operating in a Rice Fading Environment

    Directory of Open Access Journals (Sweden)

    Chenguang Shi

    2016-12-01

    Full Text Available This paper investigates the joint target parameter (delay and Doppler estimation performance of linear frequency modulation (LFM-based radar networks in a Rice fading environment. The active radar networks are composed of multiple radar transmitters and multichannel receivers placed on moving platforms. First, the log-likelihood function of the received signal for a Rician target is derived, where the received signal scattered off the target comprises of dominant scatterer (DS component and weak isotropic scatterers (WIS components. Then, the analytically closed-form expressions of the Cramer-Rao lower bounds (CRLBs on the Cartesian coordinates of target position and velocity are calculated, which can be adopted as a performance metric to access the target parameter estimation accuracy for LFM-based radar network systems in a Rice fading environment. It is found that the cumulative Fisher information matrix (FIM is a linear combination of both DS component and WIS components, and it also demonstrates that the joint CRLB is a function of signal-to-noise ratio (SNR, target’s radar cross section (RCS and transmitted waveform parameters, as well as the relative geometry between the target and the radar network architectures. Finally, numerical results are provided to indicate that the joint target parameter estimation performance of active radar networks can be significantly improved with the exploitation of DS component.

  16. Cramer-Rao Lower Bound Evaluation for Linear Frequency Modulation Based Active Radar Networks Operating in a Rice Fading Environment.

    Science.gov (United States)

    Shi, Chenguang; Salous, Sana; Wang, Fei; Zhou, Jianjiang

    2016-12-06

    This paper investigates the joint target parameter (delay and Doppler) estimation performance of linear frequency modulation (LFM)-based radar networks in a Rice fading environment. The active radar networks are composed of multiple radar transmitters and multichannel receivers placed on moving platforms. First, the log-likelihood function of the received signal for a Rician target is derived, where the received signal scattered off the target comprises of dominant scatterer (DS) component and weak isotropic scatterers (WIS) components. Then, the analytically closed-form expressions of the Cramer-Rao lower bounds (CRLBs) on the Cartesian coordinates of target position and velocity are calculated, which can be adopted as a performance metric to access the target parameter estimation accuracy for LFM-based radar network systems in a Rice fading environment. It is found that the cumulative Fisher information matrix (FIM) is a linear combination of both DS component and WIS components, and it also demonstrates that the joint CRLB is a function of signal-to-noise ratio (SNR), target's radar cross section (RCS) and transmitted waveform parameters, as well as the relative geometry between the target and the radar network architectures. Finally, numerical results are provided to indicate that the joint target parameter estimation performance of active radar networks can be significantly improved with the exploitation of DS component.

  17. DOA estimation for monostatic MIMO radar based on unitary root-MUSIC

    Science.gov (United States)

    Wang, Wei; Wang, Xianpeng; Li, Xin; Song, Hongru

    2013-11-01

    Direction of arrival (DOA) estimation is an important issue for monostatic MIMO radar. A DOA estimation method for monostatic MIMO radar based on unitary root-MUSIC is presented in this article. In the presented method, a reduced-dimension matrix is first utilised to transform the high dimension of received signal data into low dimension one. Then, a low-dimension real-value covariance matrix is obtained by forward-backward (FB) averaging and unitary transformation. The DOA of targets can be achieved by unitary root-MUSIC. Due to the FB averaging of received signal data and the eigendecomposition of the real-valued matrix covariance, the proposed method owns better angle estimation performance and lower computational complexity. The simulation results of the proposed method are presented and the performances are investigated and discussed.

  18. Signal classification method based on data mining for multi-mode radar

    Institute of Scientific and Technical Information of China (English)

    Qiang Guo; Pulong Nan; Jian Wan

    2016-01-01

    For the multi-mode radar working in the modern elec-tronic battlefield, different working states of one single radar are prone to being classified as multiple emitters when adopting traditional classification methods to process intercepted signals, which has a negative effect on signal classification. A classification method based on spatial data mining is presented to address the above chal enge. Inspired by the idea of spatial data mining, the classification method applies nuclear field to depicting the distribu-tion information of pulse samples in feature space, and digs out the hidden cluster information by analyzing distribution characteristics. In addition, a membership-degree criterion to quantify the correla-tion among al classes is established, which ensures classification accuracy of signal samples. Numerical experiments show that the presented method can effectively prevent different working states of multi-mode emitter from being classified as several emitters, and achieve higher classification accuracy.

  19. A frequency domain radar interferometric imaging (FII) technique based on high-resolution methods

    Science.gov (United States)

    Luce, H.; Yamamoto, M.; Fukao, S.; Helal, D.; Crochet, M.

    2001-01-01

    In the present work, we propose a frequency-domain interferometric imaging (FII) technique for a better knowledge of the vertical distribution of the atmospheric scatterers detected by MST radars. This is an extension of the dual frequency-domain interferometry (FDI) technique to multiple frequencies. Its objective is to reduce the ambiguity (resulting from the use of only two adjacent frequencies), inherent with the FDI technique. Different methods, commonly used in antenna array processing, are first described within the context of application to the FII technique. These methods are the Fourier-based imaging, the Capon's and the singular value decomposition method used with the MUSIC algorithm. Some preliminary simulations and tests performed on data collected with the middle and upper atmosphere (MU) radar (Shigaraki, Japan) are also presented. This work is a first step in the developments of the FII technique which seems to be very promising.

  20. Target detection for low angle radar based on multi-frequency order-statistics

    Institute of Scientific and Technical Information of China (English)

    Yunhe Cao∗; Shenghua Wang; Yu Wang; Shenghua Zhou

    2015-01-01

    For radar targets flying at low altitude, multiple pathways produce fade or enhancement relative to the level that would be expected in a free-space environment. In this paper, a new detec-tion method based on a wide-ranging multi-frequency radar for low angle targets is proposed. Sequential transmitting multiple pulses with different frequencies are first applied to decorrelate the cohe-rence of the direct and reflected echoes. After receiving al echoes, the multi-frequency samples are arranged in a sort descending ac-cording to the amplitude. Some high amplitude echoes in the same range cel are accumulated to improve the signal-to-noise ratio and the optimal number of high amplitude echoes is analyzed and given by experiments. Final y, simulation results are presented to verify the effectiveness of the method.

  1. Artificial Neural Network-Based Clutter Reduction Systems for Ship Size Estimation in Maritime Radars

    Directory of Open Access Journals (Sweden)

    Vicen-Bueno R

    2010-01-01

    Full Text Available The existence of clutter in maritime radars deteriorates the estimation of some physical parameters of the objects detected over the sea surface. For that reason, maritime radars should incorporate efficient clutter reduction techniques. Due to the intrinsic nonlinear dynamic of sea clutter, nonlinear signal processing is needed, what can be achieved by artificial neural networks (ANNs. In this paper, an estimation of the ship size using an ANN-based clutter reduction system followed by a fixed threshold is proposed. High clutter reduction rates are achieved using 1-dimensional (horizontal or vertical integration modes, although inaccurate ship width estimations are achieved. These estimations are improved using a 2-dimensional (rhombus integration mode. The proposed system is compared with a CA-CFAR system, denoting a great performance improvement and a great robustness against changes in sea clutter conditions and ship parameters, independently of the direction of movement of the ocean waves and ships.

  2. A Compensation Algorithm Based on RSPWVD-Hough Transform for Doppler Expansion in Passive Radar

    Directory of Open Access Journals (Sweden)

    Guan Xin

    2013-12-01

    Full Text Available For passive radar, long integration time is used to achieve high processing gain to detect weak target. But range migration and Doppler expansion may occur for high-speed targets. Keystone transform can be used to rectify range migration introduced by radial-speed. But tangential-speed may still lead to Doppler expansion, which entails a loss of integration gain. In this paper, signal model is presented to analyze the reason for Doppler expansion. Then, a Doppler expansion compensation method is introduced based on RSPWVD-Hough transform for multi-target scenario. Simulation results show that the proposed method can compensate the energy loss caused by Doppler expansion for multi-target scene, and it achieves good performance. The proposed method is also effective for weak targets, which means it can improve the detection ability of weak target in passive radar systems.

  3. Feasibility Study of EO SARs as Opportunity Illuminators in Passive Radars: PAZ-Based Case Study

    Directory of Open Access Journals (Sweden)

    Jose-Luis Bárcena-Humanes

    2015-11-01

    Full Text Available Passive radars exploit the signal transmitted by other systems, known as opportunity illuminators (OIs, instead of using their own transmitter. Due to its almost total invulnerability to natural disasters or physical attacks, satellite OIs are of special interest. In this line, a feasibility study of Earth Observation Synthetic Aperture Radar (EO SAR systems as OIs is carried out taking into consideration signal waveform, availability, bistatic geometry, instrumented coverage area and incident power density. A case study based on the use of PAZ, the first Spanish EO SAR, is presented. PAZ transmitted waveform, operation modes, orbit characteristics and antenna and transmitter parameters are analyzed to estimate potential coverages and resolutions. The study concludes that, due to its working in on-demand operating mode, passive radars based on PAZ-type illuminators can be proposed as complementing tools during the sensor commissioning phase, for system maintenance and for improving its performance by providing additional information about the area of interest and/or increasing the data updating speed, exploiting other sensors during the time PAZ is not available.

  4. Feasibility Study of EO SARs as Opportunity Illuminators in Passive Radars: PAZ-Based Case Study.

    Science.gov (United States)

    Bárcena-Humanes, Jose-Luis; Gómez-Hoyo, Pedro-José; Jarabo-Amores, Maria-Pilar; Mata-Moya, David; Del-Rey-Maestre, Nerea

    2015-11-17

    Passive radars exploit the signal transmitted by other systems, known as opportunity illuminators (OIs), instead of using their own transmitter. Due to its almost total invulnerability to natural disasters or physical attacks, satellite OIs are of special interest. In this line, a feasibility study of Earth Observation Synthetic Aperture Radar (EO SAR) systems as OIs is carried out taking into consideration signal waveform, availability, bistatic geometry, instrumented coverage area and incident power density. A case study based on the use of PAZ, the first Spanish EO SAR, is presented. PAZ transmitted waveform, operation modes, orbit characteristics and antenna and transmitter parameters are analyzed to estimate potential coverages and resolutions. The study concludes that, due to its working in on-demand operating mode, passive radars based on PAZ-type illuminators can be proposed as complementing tools during the sensor commissioning phase, for system maintenance and for improving its performance by providing additional information about the area of interest and/or increasing the data updating speed, exploiting other sensors during the time PAZ is not available.

  5. Anti Deceptive Jamming for MIMO Radar Based on Data Fusion and Notch Filtering (in English

    Directory of Open Access Journals (Sweden)

    Li Wei

    2013-08-01

    Full Text Available Deceptive jamming can get vivid jamming effect on Multiple-Input Multiple-Output (MIMO radar with very low power. In order to remove those deceptive targets, one method based on signal jittering, data fusion and fake target notch filtering is proposed in this paper. Multiple orthogonal binary phase codes are used as transmitted signals, before each time of transmission each transmitter will choose one signal from all the orthogonal codes, images of echoes of all kinds of codes are detected with constant false alarm rate. Targets detected in images of echoes of all different signals are fused to determine to be real or not, fake targets will be nulled by notch filtering in the image, therefore, weak real targets can be detected in the next round of detection, in this way fusion and notch filtering are implemented again and again until no fake targets exist. The effect of deceptive jamming on radar will be removed completely. Simulation result testifies that the method based on signal jittering, data fusion and notch filtering can help MIMO radar remove deceptive jamming completely.

  6. Feasibility Study of EO SARs as Opportunity Illuminators in Passive Radars: PAZ-Based Case Study

    Science.gov (United States)

    Bárcena-Humanes, Jose-Luis; Gómez-Hoyo, Pedro-José; Jarabo-Amores, Maria-Pilar; Mata-Moya, David; De-Rey-Maestre, Nerea

    2015-01-01

    Passive radars exploit the signal transmitted by other systems, known as opportunity illuminators (OIs), instead of using their own transmitter. Due to its almost total invulnerability to natural disasters or physical attacks, satellite OIs are of special interest. In this line, a feasibility study of Earth Observation Synthetic Aperture Radar (EO SAR) systems as OIs is carried out taking into consideration signal waveform, availability, bistatic geometry, instrumented coverage area and incident power density. A case study based on the use of PAZ, the first Spanish EO SAR, is presented. PAZ transmitted waveform, operation modes, orbit characteristics and antenna and transmitter parameters are analyzed to estimate potential coverages and resolutions. The study concludes that, due to its working in on-demand operating mode, passive radars based on PAZ-type illuminators can be proposed as complementing tools during the sensor commissioning phase, for system maintenance and for improving its performance by providing additional information about the area of interest and/or increasing the data updating speed, exploiting other sensors during the time PAZ is not available. PMID:26593921

  7. A novel target detection approach based on adaptive radar waveform design

    Institute of Scientific and Technical Information of China (English)

    Wang Haitao; Shi Lei; Wang Youlin; Ben De

    2013-01-01

    To resolve problems of complicated clutter,fast-varying scenes,and low signal-clutterratio (SCR) in application of target detection on sea for space-based radar (SBR),a target detection approach based on adaptive waveform design is proposed in this paper.Firstly,complicated sea clutter is modeled as compound Gaussian process,and a target is modeled as some scatterers with Gaussian reflectivity.Secondly,every dwell duration of radar is divided into several sub-dwells.Regular linear frequency modulated pulses are transmitted at Sub-dwell 1,and the received signal at this sub-dwell is used to estimate clutter covariance matrices and pre-detection.Estimated matrices are updated at every following sub-dwell by multiple particle filtering to cope with fast-varying clutter scenes of SBR.Furthermore,waveform of every following sub-dwell is designed adaptively according to mean square optimization technique.Finally,principal component analysis and generalized likelihood ratio test is used for mitigation of colored interference and property of constant false alarm rate,respectively.Simulation results show that,considering configuration of SBR and condition of complicated clutter,9 dB is reduced for SCR which reliable detection requires by this target detection approach.Therefore,the work in this paper can markedly improve radar detection performance for weak targets.

  8. Pulse Doppler radar

    CERN Document Server

    Alabaster, Clive

    2012-01-01

    This book is a practitioner's guide to all aspects of pulse Doppler radar. It concentrates on airborne military radar systems since they are the most used, most complex, and most interesting of the pulse Doppler radars; however, ground-based and non-military systems are also included. It covers the fundamental science, signal processing, hardware issues, systems design and case studies of typical systems. It will be a useful resource for engineers of all types (hardware, software and systems), academics, post-graduate students, scientists in radar and radar electronic warfare sectors and milit

  9. Model-based sub-Nyquist sampling and reconstruction technique for ultra-wideband (UWB) radar

    Science.gov (United States)

    Nguyen, Lam; Tran, Trac D.

    2010-04-01

    The Army Research Lab has recently developed an ultra-wideband (UWB) synthetic aperture radar (SAR). The radar has been employed to support proof-of-concept demonstration for several concealed target detection programs. The radar transmits and receives short impulses to achieve a wide-bandwidth from 300 MHz to 3000 MHz. Since the radar directly digitizes the wide-bandwidth receive signals, the challenges is to how to employ relatively slow and inexpensive analog-to-digital (A/D) converters to sample the signals with a rate that is greater than the minimum Nyquist rate. ARL has developed a sampling technique that allows us to employ inexpensive A/D converters (ADC) to digitize the widebandwidth signals. However, this technique still has a major drawback due to the longer time required to complete a data acquisition cycle. This in turn translates to lower average power and lower effective pulse repetition frequency (PRF). Compressed Sensing (CS) theory offers a new approach in data acquisition. From the CS framework, we can reconstruct certain signals or images from much fewer samples than the traditional sampling methods, provided that the signals are sparse in certain domains. However, while the CS framework offers the data compression feature, it still does not address the above mentioned drawback, that is the data acquisition must be operated in equivalent time since many global measurements (obtained from global random projections) are required as depicted by the sensing matrix Φ in the CS framework. In this paper, we propose a new technique that allows the sub-Nyquist sampling and the reconstruction of the wide-bandwidth data. In this technique, each wide-bandwidth radar data record is modeled as a superposition of many backscatter signals from reflective point targets. The technique is based on direct sparse recovery using a special dictionary containing many time-delayed versions of the transmitted probing signal. We demonstrate via simulated as well as

  10. Capon-based single-snapshot DOA estimation in monostatic MIMO radar

    Science.gov (United States)

    Hassanien, Aboulnasr; Amin, Moeness G.; Zhang, Yimin D.; Ahmad, Fauzia

    2015-05-01

    We consider the problem of single snapshot direction-of-arrival (DOA) estimation of multiple targets in monostatic multiple-input multiple-output (MIMO) radar. When only a single snapshot is used, the sample covariance matrix of the data becomes non-invertible and, therefore, does not permit application of Capon-based DOA estimation techniques. On the other hand, low-resolution techniques, such as the conventional beamformer, suffer from biased estimation and fail to resolve closely spaced sources. In this paper, we propose a new Capon-based method for DOA estimation in MIMO radar using a single radar pulse. Assuming that the angular locations of the sources are known a priori to be located within a certain spatial sector, we employ multiple transmit beams to focus the transmit energy of multiple orthogonal waveforms within the desired sector. The transmit weight vectors are carefully designed such that they have the same transmit power distribution pattern. As compared to the standard MIMO radar, the proposed approach enables transmitting an arbitrary number of orthogonal waveforms. By using matched-filtering at the receiver, the data associated with each beam is extracted yielding a virtual data snapshot. The total number of virtual snapshots is equal to the number of transmit beams. By choosing the number of transmit beams to be larger than the number of receive elements, it becomes possible to form a full-rank sample covariance matrix. The Capon beamformer is then applied to estimate the DOAs of the targets of interest. The proposed method is shown to have improved DOA estimation performance as compared to conventional single-snapshot DOA estimation methods.

  11. Satellite Formation Design for Space Based Radar Applications

    Science.gov (United States)

    2007-07-30

    Practical Guidance Methodology for Relative Motion of LEO Spacecraft Based on the Clohessy-Wiltshire Equations,” AAS Paper 04-252, AAS/AIAA Space...Non- Circular Reference Orbit," AAS Paper 01-222, AAS/AIAA Space Flight Mechanics Meeting, Santa Barbara, CA, Feb 11-16, 2001. 11. D. Brouwer ...Small Eccentricities or Inclinations in the Brouwer Theory of the Artificial Satellite,” The Astronomical Journal, Vol. 68, October 1963, pp. 555

  12. MICROPROCESSOR-BASED DATA-ACQUISITION SYSTEM FOR A BOREHOLE RADAR.

    Science.gov (United States)

    Bradley, Jerry A.; Wright, David L.

    1987-01-01

    An efficient microprocessor-based system is described that permits real-time acquisition, stacking, and digital recording of data generated by a borehole radar system. Although the system digitizes, stacks, and records independently of a computer, it is interfaced to a desktop computer for program control over system parameters such as sampling interval, number of samples, number of times the data are stacked prior to recording on nine-track tape, and for graphics display of the digitized data. The data can be transferred to the desktop computer during recording, or it can be played back from a tape at a latter time. Using the desktop computer, the operator observes results while recording data and generates hard-copy graphics in the field. Thus, the radar operator can immediately evaluate the quality of data being obtained, modify system parameters, study the radar logs before leaving the field, and rerun borehole logs if necessary. The system has proven to be reliable in the field and has increased productivity both in the field and in the laboratory.

  13. Time-Expanded Sampling for Ensemble-Based Filters:Assimilation Experiments with Real Radar Observations

    Institute of Scientific and Technical Information of China (English)

    LU Huijuan; Qin XU; YAO Mingming; GAO Shouting

    2011-01-01

    By sampling perturbed state vectors from each ensenble prediction run at properly selected time levels in the vicinity of the analysis time, the recently proposed time-expanded sampling approach can enlarge the ensemble size without increasing the number of prediction runs and, hence, can reduce the computational cost of an ensemble-based filter. In this study, this approach is tested for the first time with real radar data from a tornadic thunderstorm. In particular, four assimilation experiments were performed to test the time-expanded sampling method against the conventional ensemble sampling method used by ensemblebased filters. In these experiments, the ensemble square-root filter (EnSRF) was used with 45 ensemble members generated by the time-expanded sampling and conventional sampling from 15 and 45 prediction runs, respectively, and quality-controlled radar data were compressed into super-observations with properly reduced spatial resolutions to improve the EnSRF performances. The results show that the time-expanded sampling approach not only can reduce the computational cost but also can improve the accuracy of the analysis, especially when the ensemble size is severely limited due to computational constraints for real-radar data assimilation. These potential merits are consistent with those previously demonstrated by assimilation experiments with simulated data.

  14. Synthetic aperture radar (SAR-based mapping of volcanic flows: Manam Island, Papua New Guinea

    Directory of Open Access Journals (Sweden)

    J. K. Weissel

    2004-01-01

    Full Text Available We present new radar-based techniques for efficient identification of surface changes generated by lava and pyroclastic flows, and apply these to the 1996 eruption of Manam Volcano, Papua New Guinea. Polarimetric L- and P-band airborne synthetic aperture radar (SAR data, along with a C-band DEM, were acquired over the volcano on 17 November 1996 during a major eruption sequence. The L-band data are analyzed for dominant scattering mechanisms on a per pixel basis using radar target decomposition techniques. A classification method is presented, and when applied to the L-band polarimetry, it readily distinguishes bare surfaces from forest cover over Manam volcano. In particular, the classification scheme identifies a post-1992 lava flow in NE Valley of Manam Island as a mainly bare surface and the underlying 1992 flow units as mainly vegetated surfaces. The Smithsonian's Global Volcanism Network reports allow us to speculate whether the bare surface is a flow dating from October or November in the early part of the late-1996 eruption sequence. This work shows that fully polarimetric SAR is sensitive to scattering mechanism changes caused by volcanic resurfacing processes such as lava and pyroclastic flows. By extension, this technique should also prove useful in mapping debris flows, ash deposits and volcanic landslides associated with major eruptions.

  15. Indoor locating and inventory management based on RFID-Radar detecting data

    Science.gov (United States)

    Chang, C. C.; Lou, P. C.; Hsieh, Y. G.

    2012-03-01

    The new generation RFID-Radar system provides the function of detecting the targets' locations with the measurements of range and angle using a reader and an antenna array to transmit and receive the RF signals. It enhances the application value for RFID when combined with the geospatial information. In this study, an information system embedded with a plan coordinate detection function was developed using the spatial data provided by the RFID-Radar system, to expand the application of indoor locating and meet the inventory management requirements. The in-house developed management system can work for processing the measurements detected by the RFID-Radar system, calculating the target's location, checking the target's status and analyzing the target's movement occurring between the two detecting epochs through a designed GUI (graphical user interface). The system has been tested to show an internal precision of 0.76 m for locating, based on the stability test of the range and angle measurements, and effectively demonstrates the functions for detecting the target's movement and archiving the inventory's management information with a database.

  16. FORTRAN program for analyzing ground-based radar data: Usage and derivations, version 6.2

    Science.gov (United States)

    Haering, Edward A., Jr.; Whitmore, Stephen A.

    1995-01-01

    A postflight FORTRAN program called 'radar' reads and analyzes ground-based radar data. The output includes position, velocity, and acceleration parameters. Air data parameters are also provided if atmospheric characteristics are input. This program can read data from any radar in three formats. Geocentric Cartesian position can also be used as input, which may be from an inertial navigation or Global Positioning System. Options include spike removal, data filtering, and atmospheric refraction corrections. Atmospheric refraction can be corrected using the quick White Sands method or the gradient refraction method, which allows accurate analysis of very low elevation angle and long-range data. Refraction properties are extrapolated from surface conditions, or a measured profile may be input. Velocity is determined by differentiating position. Accelerations are determined by differentiating velocity. This paper describes the algorithms used, gives the operational details, and discusses the limitations and errors of the program. Appendices A through E contain the derivations for these algorithms. These derivations include an improvement in speed to the exact solution for geodetic altitude, an improved algorithm over earlier versions for determining scale height, a truncation algorithm for speeding up the gradient refraction method, and a refinement of the coefficients used in the White Sands method for Edwards AFB, California. Appendix G contains the nomenclature.

  17. Precipitation and microphysical processes observed by three polarimetric X-band radars and ground-based instrumentation during HOPE

    OpenAIRE

    Xie, Xinxin; Evaristo, Raquel; Simmer, Clemens; Handwerker, Jan; Trömel, Silke

    2016-01-01

    This study presents a first analysis of precipitation and related microphysical processes observed by three polarimetric X-band Doppler radars (BoXPol, JuXPol and KiXPol) in conjunction with a ground-based network of disdrometers, rain gauges and vertically pointing micro rain radars (MRRs) during the High Definition Clouds and Precipitation for advancing Climate Prediction (HD(CP)2) Observational Prototype Experiment (HOPE) during April and May 2013 in Germany. While JuXPol...

  18. Quasi-Coherent Noise Jamming to LFM Radar Based on Pseudo-random Sequence Phase-modulation

    OpenAIRE

    2015-01-01

    A novel quasi-coherent noise jamming method is proposed against linear frequency modulation (LFM) signal and pulse compression radar. Based on the structure of digital radio frequency memory (DRFM), the jamming signal is acquired by the pseudo-random sequence phase-modulation of sampled radar signal. The characteristic of jamming signal in time domain and frequency domain is analyzed in detail. Results of ambiguity function indicate that the blanket jamming effect along the range direction wi...

  19. Efficient one-stationary bistatic synthetic aperture radar raw data generation based on Fourier analysis

    Science.gov (United States)

    Huang, Yulin; Wu, Junjie; Li, Zhongyu; Yang, Haiguang; Yang, Jianyu

    2016-01-01

    Raw data generation for synthetic aperture radar (SAR) is very powerful for designing systems and testing imaging algorithms. In this paper, a raw data generation method based on Fourier analysis for one-stationary bistatic SAR is presented. In this mode, two-dimensional (2-D) spatial variation is the major problem faced by the fast Fourier transform-based raw data generation. To deal with this problem, a 2-D linearization followed by a 2-D frequency transformation is employed in this method. This frequency transformation can reflect the 2-D spatial variation. Residual phase compensation is also discussed. Numerical simulation verifies the method.

  20. Boost-Phase ballistic missile trajectory estimation with ground based radar

    Institute of Scientific and Technical Information of China (English)

    Tang Yuyan; Huang Peikang

    2006-01-01

    A conditional boost-phase trajectory estimation method based on ballistic missile (BM) information database and classification is developed to estimate and predict boos-phase BM trajectory. The main uncertain factors to describe BM dynamics equation are reduced to the control law of trajectory pitch angle in boost-phase. After the BM mass at the beginning of estimation, the BM attack angle and the modification of engine thrust denoting BM acceleration are modeled reasonably, the boost-phase BM trajectory estimation with ground based radar is well realized. The validity of this estimation method is testified by computer simulation with a typical example.

  1. Automatic prediction of time to failure of open pit mine slopes based on radar monitoring and inverse velocity method

    Institute of Scientific and Technical Information of China (English)

    Osasan K.S.; Stacey T.R

    2014-01-01

    Radar slope monitoring is now widely used across the world, for example, the slope stability radar (SSR) and the movement and surveying radar (MSR) are currently in use in many mines around the world. However, to fully realize the effectiveness of this radar in notifying mine personnel of an impending slope failure, a method that can confidently predict the time of failure is necessary. The model developed in this study is based on the inverse velocity method pioneered by Fukuzono in 1985. The model named the slope failure prediction model (SFPM) was validated with the displacement data from two slope failures monitored with the MSR. The model was found to be very effective in predicting the time to failure while providing adequate evacuation time once the progressive displacement stage is reached.

  2. Intercomparison of Vertical Structure of Storms Revealed by Ground-Based (NMQ and Spaceborne Radars (CloudSat-CPR and TRMM-PR

    Directory of Open Access Journals (Sweden)

    Veronica M. Fall

    2013-01-01

    Full Text Available Spaceborne radars provide great opportunities to investigate the vertical structure of clouds and precipitation. Two typical spaceborne radars for such a study are the W-band Cloud Profiling Radar (CPR and Ku-band Precipitation Radar (PR, which are onboard NASA’s CloudSat and TRMM satellites, respectively. Compared to S-band ground-based radars, they have distinct scattering characteristics for different hydrometeors in clouds and precipitation. The combination of spaceborne and ground-based radar observations can help in the identification of hydrometeors and improve the radar-based quantitative precipitation estimation (QPE. This study analyzes the vertical structure of the 18 January, 2009 storm using data from the CloudSat CPR, TRMM PR, and a NEXRAD-based National Mosaic and Multisensor QPE (NMQ system. Microphysics above, within, and below the melting layer are studied through an intercomparison of multifrequency measurements. Hydrometeors’ type and their radar scattering characteristics are analyzed. Additionally, the study of the vertical profile of reflectivity (VPR reveals the brightband properties in the cold-season precipitation and its effect on the radar-based QPE. In all, the joint analysis of spaceborne and ground-based radar data increases the understanding of the vertical structure of storm systems and provides a good insight into the microphysical modeling for weather forecasts.

  3. Ground-based radar reflectivity mosaic of mei-yu precipitation systems over the Yangtze River-Huaihe River basins

    Science.gov (United States)

    Luo, Yali; Qian, Weimiao; Gong, Yu; Wang, Hongyan; Zhang, Da-Lin

    2016-11-01

    The 3D radar reflectivity produced by a mosaic software system, with measurements from 29 operational weather radars in the Yangtze River-Huaihe River Basins (YRHRB) during the mei-yu season of 2007, is compared to coincident TRMM PR observations in order to evaluate the value of the ground-based radar reflectivity mosaic in characterizing the 3D structures of mei-yu precipitation. Results show reasonable agreement in the composite radar reflectivity between the two datasets, with a correlation coefficient of 0.8 and a mean bias of -1 dB. The radar mosaic data at constant altitudes are reasonably consistent with the TRMM PR observations in the height range of 2-5 km, revealing essentially the same spatial distribution of radar echo and nearly identical histograms of reflectivity. However, at altitudes above 5 km, the mosaic data overestimate reflectivity and have slower decreasing rates with height compared to the TRMM PR observations. The areas of convective and stratiform precipitation, based on the mosaic reflectivity distribution at 3-km altitude, are highly correlated with the corresponding regions in the TRMM products, with correlation coefficients of 0.92 and 0.97 and mean relative differences of -7.9% and -2.5%, respectively. Finally, the usefulness of the mosaic reflectivity at 3-km altitude at 6-min intervals is illustrated using a mesoscale convective system that occurred over the YRHRB.

  4. Segmentation of synthetic aperture radar image using multiscale information measure-based spectral clustering

    Institute of Scientific and Technical Information of China (English)

    Haixia Xu; Zheng Tian; Mingtao Ding

    2008-01-01

    @@ A multiscale information measure (MIM), calculable from per-pixel wavelet coefficients, but relying on global statistics of synthetic aperture radar (SAR) image, is proposed. It fully exploits the variations in speckle pattern when the image resolution varies from course to fine, thus it can capture the intrinsic texture of the scene backscatter and the texture due to speckle simultaneously. Graph spectral segmentation methods based on MIM and the usual similarity measure are carried out on two real SAR images.Experimental results show that MIM can characterize texture information of SAR image more effectively than the commonly used similarity measure.

  5. Frequency Extrapolation by Floating Genetic Algorithm Based on GTD Model for Radar Cross Section

    Institute of Scientific and Technical Information of China (English)

    YANG Zhenglong; FANG Dagang; SHENG Weixing; LIU Tiejun; ZHUANG Jing

    2001-01-01

    A frequency extrapolation scheme isdeveloped to effectively predict radar cross section us-ing floating genetic algorithm based on the GTD (ge-ometry theory of diffraction) model. The parameter-ized model to extrapolate the frequency response tohigher (or lower) frequency band is used and somepractical targets are calculated to test the effective-ness of the method. The influence of extrapolationon the range profile is studied. Furthermore, the re-lationship between the fitting precision and extrap-olation ability is considered. Different extrapolationprocedures are discussed.

  6. Complex Wishart distribution based analysis of polarimetric synthetic aperture radar data

    DEFF Research Database (Denmark)

    Nielsen, Allan Aasbjerg; Skriver, Henning; Conradsen, Knut

    2007-01-01

    Multi-look, polarimetric synthetic aperture radar (SAR) data are often worked with in the so-called covariance matrix representation. For each pixel this representation gives a 3x3 Hermitian, positive definite matrix which follows a complex Wishart distribution. Based on this distribution a test...... statistic for equality of two such matrices and an associated asymptotic probability for obtaining a smaller value of the test statistic are given and applied to change detection, edge detection and segmentation in polarimetric SAR data. In a case study EMISAR L-band data from 17 April 1998 and 20 May 1998...

  7. Detection of weak target for MIMO radar based on Hough transform

    Institute of Scientific and Technical Information of China (English)

    Zeng Jiankui; He Zishu

    2009-01-01

    An effective method of multiple input multiple output (MIMO) radar weak target detection is proposed based on the Hough transform. The detection time duration is divided into multiple coherent processing intervals (CPIs). Within each CPI, conventional methods such as fast Fourier transform (FFT) is exploit to coherent inte-grating in same range cell. Furthermore, noncoherent integration through several range cells can be implemented by Hough transform among all CPIs. Thus, higher integration gain can be obtained. Simulation results are also given to demonstrate that the detection performance of weak moving target can be dramatically improved.

  8. Low velocity target detection based on time-frequency image for high frequency ground wave radar

    Institute of Scientific and Technical Information of China (English)

    YAN Songhua; WU Shicai; WEN Biyang

    2007-01-01

    The Doppler spectral broadening resulted from non-stationary movement of target and radio-frequency interference will decrease the veracity of target detection by high frequency ground wave(HEGW)radar.By displaying the change of signal energy on two dimensional time-frequency images based on time-frequency analysis,a new mathematical morphology method to distinguish target from nonlinear time-frequency curves is presented.The analyzed results from the measured data verify that with this new method the target can be detected correctly from wide Doppler spectrum.

  9. Towards a radar- and observation-based hail climatology for Germany

    Directory of Open Access Journals (Sweden)

    Thomas Junghänel

    2016-09-01

    Full Text Available In the German Strategy for Adaptation to Climate Change hail is identified as one of the major subjects of concern regarding transport infrastructure. Moreover hailstorms are a major threat to e.g. agriculture and the automobile industry causing significant economical damages and losses. Despite these significant hail-related meteorological risks no comprehensive observation-based hail climatology for Germany exists. In this study we present a new approach to this task, combining radar data with different kinds of hail reports, such as ground observation and agricultural insurance data. Preprocessing ensures the applicability of the radar data for the presented climatological analysis. In this sense a number of detection methods are applied to filter artefacts, especially clutter pixels and spokes that disrupt radar measurements. To construct a reliable hail climatology for Germany we process all information into a 10‑year based annual average number of hail days on a 1km×1km$1\\,\\text{km}\\times1\\,\\text{km}$ grid using a two-path hail criterion. While the first path combines a threshold of 50 dBZ with a hail report, the second path is based on a 55 dBZ threshold only. By adding radar data we increase the spatial representativity of the ground based hail reports and gain additional information in regions which lack observational data. Overall, the results are mainly determined by events derived from the first path (68 %. A validation of our dataset at 65 stations of Deutscher Wetterdienst shows that the method slightly underestimates the number of hail days, especially for mountainous regions. This results in a better adaption of the hail criterion to lowlands. The resulting hail frequency map shows an increase in the average number of hail days per year from north to south. In particular, hailstorms occur less frequently in the Central North German Plain and the Mecklenburg Coastal Lowland, whereas the highest number of hail days

  10. Single channel source separation of radar fuze mixed signal based on phase difference analysis

    Institute of Scientific and Technical Information of China (English)

    Hang ZHU; Shu-ning ZHANG; Hui-chang ZHAO

    2014-01-01

    A new method based on phase difference analysis is proposed for the single-channel mixed signal separation of single-channel radar fuze. This method is used to estimate the mixing coefficients of de-noised signals through the cumulants of mixed signals, solve the candidate data set by the mixing coefficients and signal analytical form, and resolve the problem of vector ambiguity by analyzing the phase differences. The signal separation is realized by exchanging data of the solutions. The waveform similarity coefficients are calculated, and the timeefrequency dis-tributions of separated signals are analyzed. The results show that the proposed method is effective.

  11. Singularity-sensitive gauge-based radar rainfall adjustment methods for urban hydrological applications

    Directory of Open Access Journals (Sweden)

    L.-P. Wang

    2015-02-01

    Full Text Available Gauge-based radar rainfall adjustment techniques have been widely used to improve the applicability of radar rainfall estimates to large-scale hydrological modelling. However, their use for urban hydrological applications is limited as they were mostly developed based upon Gaussian approximations and therefore tend to smooth off so-called "singularities" (features of a non-Gaussian field that can be observed in the fine-scale rainfall structure. Overlooking the singularities could be critical, given that their distribution is highly consistent with that of local extreme magnitudes. This deficiency may cause large errors in the subsequent urban hydrological modelling. To address this limitation and improve the applicability of adjustment techniques at urban scales, a method is proposed herein which incorporates a local singularity analysis into existing adjustment techniques and allows the preservation of the singularity structures throughout the adjustment process. In this paper the proposed singularity analysis is incorporated into the Bayesian merging technique and the performance of the resulting singularity-sensitive method is compared with that of the original Bayesian (non singularity-sensitive technique and the commonly-used mean field bias adjustment. This test is conducted using as case study four storm events observed in the Portobello catchment (53 km2 (Edinburgh, UK during 2011 and for which radar estimates, dense rain gauge and sewer flow records, as well as a recently-calibrated urban drainage model were available. The results suggest that, in general, the proposed singularity-sensitive method can effectively preserve the non-normality in local rainfall structure, while retaining the ability of the original adjustment techniques to generate nearly unbiased estimates. Moreover, the ability of the singularity-sensitive technique to preserve the non-normality in rainfall estimates often leads to better reproduction of the urban

  12. Doppler radar physiological sensing

    CERN Document Server

    Lubecke, Victor M; Droitcour, Amy D; Park, Byung-Kwon; Singh, Aditya

    2016-01-01

    Presents a comprehensive description of the theory and practical implementation of Doppler radar-based physiological monitoring. This book includes an overview of current physiological monitoring techniques and explains the fundamental technology used in remote non-contact monitoring methods. Basic radio wave propagation and radar principles are introduced along with the fundamentals of physiological motion and measurement. Specific design and implementation considerations for physiological monitoring radar systems are then discussed in detail. The authors address current research and commercial development of Doppler radar based physiological monitoring for healthcare and other applications.

  13. Fiber-distributed Ultra-wideband noise radar with steerable power spectrum and colorless base station.

    Science.gov (United States)

    Zheng, Jianyu; Wang, Hui; Fu, Jianbin; Wei, Li; Pan, Shilong; Wang, Lixian; Liu, Jianguo; Zhu, Ninghua

    2014-03-10

    A fiber-distributed Ultra-wideband (UWB) noise radar was achieved, which consists of a chaotic UWB noise source based on optoelectronic oscillator (OEO), a fiber-distributed transmission link, a colorless base station (BS), and a cross-correlation processing module. Due to a polarization modulation based microwave photonic filter and an electrical UWB pass-band filter embedded in the feedback loop of the OEO, the power spectrum of chaotic UWB signal could be shaped and notch-filtered to avoid the spectrum-overlay-induced interference to the narrow band signals. Meanwhile, the wavelength-reusing could be implemented in the BS by means of the distributed polarization modulation-to-intensity modulation conversion. The experimental comparison for range finding was carried out as the chaotic UWB signal was notch-filtered at 5.2 GHz and 7.8 GHz or not. Measured results indicate that space resolution with cm-level could be realized after 3-km fiber transmission thanks to the excellent self-correlation property of the UWB noise signal provided by the OEO. The performance deterioration of the radar raised by the energy loss of the notch-filtered noise signal was negligible.

  14. Ground-based microwave weather radar observations and retrievals during the 2014 Holuhraun eruption (Bárðarbunga, Iceland)

    Science.gov (United States)

    Mereu, Luigi; Silvio Marzano, Frank; Barsotti, Sara; Montopoli, Mario; Yeo, Richard; Arngrimsson, Hermann; Björnsson, Halldór; Bonadonna, Costanza

    2015-04-01

    During an eruptive event the real-time forecasting of ash dispersal into the atmosphere is a key factor to prevent air traffic disasters. The ash plume is extremely hazardous to aircraft that inadvertently may fly through it. Real-time monitoring of such phenomena is crucial, particularly to obtain specific data for the initialization of eruption and dispersion models in terms of source parameters. The latter, such as plume height, ash concentration, mass flow rate and size spectra, are usually very difficult to measure or to estimate with a relatively good accuracy. Over the last years different techniques have been developed to improved ash plume detection and retrieval. Satellite-based observations, using multi-frequency visible and infrared radiometers, are usually exploited for monitoring and measuring dispersed ash clouds. The observations from geostationary orbit suffer from a relatively poor spatial resolution, whereas the low orbit level has a relatively poor temporal resolution. Moreover, the field-of-view of infrared radiometric measurements may be reduced by obstructions caused by water and ice clouds lying between the ground and the sensor's antenna. Weather radar-based observations represent an emerging technique to detect and, to a certain extent, mitigate the hazard from the ash plumes. Ground-based microwave scanning radar systems can provide the three-dimensional information about the detected ash volume with a fairly high spatial resolution every few minutes and in all weather conditions. Methodological studies have recently investigated the possibility of using single-polarization and dual-polarization ground-based radar for the remote sensing of volcanic ash cloud. In this respect, radar observations can be complementary to satellite observations. A microphysical electromagnetic characterization of volcanic ash was carried out in terms of dielectric properties, composition, size and orientation of ash particles. An extended Volcanic Ash Radar

  15. Change Detection in Synthetic Aperture Radar Images Based on Deep Neural Networks.

    Science.gov (United States)

    Gong, Maoguo; Zhao, Jiaojiao; Liu, Jia; Miao, Qiguang; Jiao, Licheng

    2016-01-01

    This paper presents a novel change detection approach for synthetic aperture radar images based on deep learning. The approach accomplishes the detection of the changed and unchanged areas by designing a deep neural network. The main guideline is to produce a change detection map directly from two images with the trained deep neural network. The method can omit the process of generating a difference image (DI) that shows difference degrees between multitemporal synthetic aperture radar images. Thus, it can avoid the effect of the DI on the change detection results. The learning algorithm for deep architectures includes unsupervised feature learning and supervised fine-tuning to complete classification. The unsupervised feature learning aims at learning the representation of the relationships between the two images. In addition, the supervised fine-tuning aims at learning the concepts of the changed and unchanged pixels. Experiments on real data sets and theoretical analysis indicate the advantages, feasibility, and potential of the proposed method. Moreover, based on the results achieved by various traditional algorithms, respectively, deep learning can further improve the detection performance.

  16. Efficient Transmit Beamspace Design for Search-Free Based DOA Estimation in MIMO Radar

    Science.gov (United States)

    Khabbazibasmenj, Arash; Hassanien, Aboulnasr; Vorobyov, Sergiy A.; Morency, Matthew W.

    2014-03-01

    In this paper, we address the problem of transmit beamspace design for multiple-input multiple-output (MIMO) radar with colocated antennas in application to direction-of-arrival (DOA) estimation. A new method for designing the transmit beamspace matrix that enables the use of search-free DOA estimation techniques at the receiver is introduced. The essence of the proposed method is to design the transmit beamspace matrix based on minimizing the difference between a desired transmit beampattern and the actual one under the constraint of uniform power distribution across the transmit array elements. The desired transmit beampattern can be of arbitrary shape and is allowed to consist of one or more spatial sectors. The number of transmit waveforms is even but otherwise arbitrary. To allow for simple search-free DOA estimation algorithms at the receive array, the rotational invariance property is established at the transmit array by imposing a specific structure on the beamspace matrix. Semi-definite relaxation is used to transform the proposed formulation into a convex problem that can be solved efficiently. We also propose a spatial-division based design (SDD) by dividing the spatial domain into several subsectors and assigning a subset of the transmit beams to each subsector. The transmit beams associated with each subsector are designed separately. Simulation results demonstrate the improvement in the DOA estimation performance offered by using the proposed joint and SDD transmit beamspace design methods as compared to the traditional MIMO radar technique.

  17. Sparsity-Based Space-Time Adaptive Processing Using OFDM Radar

    Energy Technology Data Exchange (ETDEWEB)

    Sen, Satyabrata [ORNL

    2012-01-01

    We propose a sparsity-based space-time adaptive processing (STAP) algorithm to detect a slowly-moving target using an orthogonal frequency division multiplexing (OFDM) radar. We observe that the target and interference spectra are inherently sparse in the spatio-temporal domain, and hence we exploit that sparsity to develop an efficient STAP technique. In addition, the use of an OFDM signal increases the frequency diversity of our system, as different scattering centers of a target resonate at different frequencies, and thus improves the target detectability. First, we formulate a realistic sparse-measurement model for an OFDM radar considering both the clutter and jammer as the interfering sources. Then, we show that the optimal STAP-filter weight-vector is equal to the generalized eigenvector corresponding to the minimum generalized eigenvalue of the interference and target covariance matrices. To estimate the target and interference covariance matrices, we apply a residual sparse-recovery technique that enables us to incorporate the partially known support of the sparse vector. Our numerical results demonstrate that the sparsity-based STAP algorithm, with considerably lesser number of secondary data, produces an equivalent performance as the other existing STAP techniques.

  18. Radar operation in a hostile electromagnetic environment

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter

    2014-03-01

    Radar ISR does not always involve cooperative or even friendly targets. An adversary has numerous techniques available to him to counter the effectiveness of a radar ISR sensor. These generally fall under the banner of jamming, spoofing, or otherwise interfering with the EM signals required by the radar sensor. Consequently mitigation techniques are prudent to retain efficacy of the radar sensor. We discuss in general terms a number of mitigation techniques.

  19. Intercomparison of snowfall estimates derived from the CloudSat Cloud Profiling Radar and the ground-based weather radar network over Sweden

    Directory of Open Access Journals (Sweden)

    L. Norin

    2015-12-01

    Full Text Available Accurate snowfall estimates are important for both weather and climate applications. Ground-based weather radars and space-based satellite sensors are often used as viable alternatives to rain gauges to estimate precipitation in this context. In particular, the Cloud Profiling Radar (CPR on board CloudSat is proving to be a useful tool to map snowfall globally, in part due to its high sensitivity to light precipitation and its ability to provide near-global vertical structure. CloudSat snowfall estimates play a particularly important role in the high-latitude regions as other ground-based observations become sparse and passive satellite sensors suffer from inherent limitations. In this paper, snowfall estimates from two observing systems – Swerad, the Swedish national weather radar network, and CloudSat – are compared. Swerad offers a well-calibrated data set of precipitation rates with high spatial and temporal resolution, at very high latitudes. The measurements are anchored to rain gauges and provide valuable insights into the usefulness of CloudSat CPR's snowfall estimates in the polar regions. In total, 7.2 × 105 matchups of CloudSat and Swerad observations from 2008 through 2010 were intercompared, covering all but the summer months (June to September. The intercomparison shows encouraging agreement between the two observing systems despite their different sensitivities and user applications. The best agreement is observed when CloudSat passes close to a Swerad station (46–82 km, where the observational conditions for both systems are comparable. Larger disagreements outside this range suggest that both platforms have difficulty with shallow snow but for different reasons. The correlation between Swerad and CloudSat degrades with increasing distance from the nearest Swerad station, as Swerad's sensitivity decreases as a function of distance. Swerad also tends to overshoot low-level precipitating systems further away from the station

  20. Video segmentation using multiple features based on EM algorithm

    Institute of Scientific and Technical Information of China (English)

    张风超; 杨杰; 刘尔琦

    2004-01-01

    Object-based video segmentation is an important issue for many multimedia applications. A video segmentation method based on EM algorithm is proposed. We consider video segmentation as an unsupervised classification problem and apply EM algorithm to obtain the maximum-likelihood estimation of the Gaussian model parameters for model-based segmentation. We simultaneously combine multiple features (motion, color) within a maximum likelihood framework to obtain accurate segment results. We also use the temporal consistency among video frames to improve the speed of EM algorithm. Experimental results on typical MPEG-4 sequences and real scene sequences show that our method has an attractive accuracy and robustness.

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

    Science.gov (United States)

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

    2013-12-01

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

  2. Towards Contactless Silent Speech Recognition Based on Detection of Active and Visible Articulators Using IR-UWB Radar.

    Science.gov (United States)

    Shin, Young Hoon; Seo, Jiwon

    2016-10-29

    People with hearing or speaking disabilities are deprived of the benefits of conventional speech recognition technology because it is based on acoustic signals. Recent research has focused on silent speech recognition systems that are based on the motions of a speaker's vocal tract and articulators. Because most silent speech recognition systems use contact sensors that are very inconvenient to users or optical systems that are susceptible to environmental interference, a contactless and robust solution is hence required. Toward this objective, this paper presents a series of signal processing algorithms for a contactless silent speech recognition system using an impulse radio ultra-wide band (IR-UWB) radar. The IR-UWB radar is used to remotely and wirelessly detect motions of the lips and jaw. In order to extract the necessary features of lip and jaw motions from the received radar signals, we propose a feature extraction algorithm. The proposed algorithm noticeably improved speech recognition performance compared to the existing algorithm during our word recognition test with five speakers. We also propose a speech activity detection algorithm to automatically select speech segments from continuous input signals. Thus, speech recognition processing is performed only when speech segments are detected. Our testbed consists of commercial off-the-shelf radar products, and the proposed algorithms are readily applicable without designing specialized radar hardware for silent speech processing.

  3. Towards Contactless Silent Speech Recognition Based on Detection of Active and Visible Articulators Using IR-UWB Radar

    Directory of Open Access Journals (Sweden)

    Young Hoon Shin

    2016-10-01

    Full Text Available People with hearing or speaking disabilities are deprived of the benefits of conventional speech recognition technology because it is based on acoustic signals. Recent research has focused on silent speech recognition systems that are based on the motions of a speaker’s vocal tract and articulators. Because most silent speech recognition systems use contact sensors that are very inconvenient to users or optical systems that are susceptible to environmental interference, a contactless and robust solution is hence required. Toward this objective, this paper presents a series of signal processing algorithms for a contactless silent speech recognition system using an impulse radio ultra-wide band (IR-UWB radar. The IR-UWB radar is used to remotely and wirelessly detect motions of the lips and jaw. In order to extract the necessary features of lip and jaw motions from the received radar signals, we propose a feature extraction algorithm. The proposed algorithm noticeably improved speech recognition performance compared to the existing algorithm during our word recognition test with five speakers. We also propose a speech activity detection algorithm to automatically select speech segments from continuous input signals. Thus, speech recognition processing is performed only when speech segments are detected. Our testbed consists of commercial off-the-shelf radar products, and the proposed algorithms are readily applicable without designing specialized radar hardware for silent speech processing.

  4. An Entropy-Based Propagation Speed Estimation Method for Near-Field Subsurface Radar Imaging

    Directory of Open Access Journals (Sweden)

    Pistorius Stephen

    2010-01-01

    Full Text Available During the last forty years, Subsurface Radar (SR has been used in an increasing number of noninvasive/nondestructive imaging applications, ranging from landmine detection to breast imaging. To properly assess the dimensions and locations of the targets within the scan area, SR data sets have to be reconstructed. This process usually requires the knowledge of the propagation speed in the medium, which is usually obtained by performing an offline measurement from a representative sample of the materials that form the scan region. Nevertheless, in some novel near-field SR scenarios, such as Microwave Wood Inspection (MWI and Breast Microwave Radar (BMR, the extraction of a representative sample is not an option due to the noninvasive requirements of the application. A novel technique to determine the propagation speed of the medium based on the use of an information theory metric is proposed in this paper. The proposed method uses the Shannon entropy of the reconstructed images as the focal quality metric to generate an estimate of the propagation speed in a given scan region. The performance of the proposed algorithm was assessed using data sets collected from experimental setups that mimic the dielectric contrast found in BMI and MWI scenarios. The proposed method yielded accurate results and exhibited an execution time in the order of seconds.

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

    Science.gov (United States)

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

    2016-05-01

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

  6. Determining the Best Method for Estimating the Observed Level of Maximum Detrainment Based on Radar Reflectivity

    Energy Technology Data Exchange (ETDEWEB)

    Carletta, Nicholas D.; Mullendore, Gretchen L.; Starzec, Mariusz; Xi, Baike; Feng, Zhe; Dong, Xiquan

    2016-08-01

    Convective mass transport is the transport of mass from near the surface up to the upper troposphere and lower stratosphere (UTLS) by a deep convective updraft. This transport can alter the chemical makeup and water vapor balance of the UTLS, which affects cloud formation and the radiative properties of the atmosphere. It is therefore important to understand the exact altitudes at which mass is detrained from convection. The purpose of this study was to improve upon previously published methodologies for estimating the level of maximum detrainment (LMD) within convection using data from a single ground-based radar. Four methods were used to identify the LMD and validated against dual-Doppler derived vertical mass divergence fields for six cases with a variety of storm types. The best method for locating the LMD was determined to be the method that used a reflectivity texture technique to determine convective cores and a multi-layer echo identification to determine anvil locations. Although an improvement over previously published methods, the new methodology still produced unreliable results in certain regimes. The methodology worked best when applied to mature updrafts, as the anvil needs time to grow to a detectable size. Thus, radar reflectivity is found to be valuable in estimating the LMD, but storm maturity must also be considered for best results.

  7. Nuclear reactor power for a space-based radar. SP-100 project

    Science.gov (United States)

    Bloomfield, Harvey; Heller, Jack; Jaffe, Leonard; Beatty, Richard; Bhandari, Pradeep; Chow, Edwin; Deininger, William; Ewell, Richard; Fujita, Toshio; Grossman, Merlin

    1986-01-01

    A space-based radar mission and spacecraft, using a 300 kWe nuclear reactor power system, has been examined, with emphasis on aspects affecting the power system. The radar antenna is a horizontal planar array, 32 X 64 m. The orbit is at 61 deg, 1088 km. The mass of the antenna with support structure is 42,000 kg; of the nuclear reactor power system, 8,300 kg; of the whole spacecraft about 51,000 kg, necessitating multiple launches and orbital assembly. The assembly orbit is at 57 deg, 400 km, high enough to provide the orbital lifetime needed for orbital assembly. The selected scenario uses six Shuttle launches to bring the spacecraft and a Centaur G upper-stage vehicle to assembly orbit. After assembly, the Centaur places the spacecraft in operational orbit, where it is deployed on radio command, the power system started, and the spacecraft becomes operational. Electric propulsion is an alternative and allows deployment in assembly orbit, but introduces a question of nuclear safety.

  8. Improvement of Radar Quantitative Precipitation Estimation Based on Real-Time Adjustments to Z-R Relationships and Inverse Distance Weighting Correction Schemes

    Institute of Scientific and Technical Information of China (English)

    WANG Gaili; LIU Liping; DING Yuanyuan

    2012-01-01

    The errors in radar quantitative precipitation estimations consist not only of systematic biases caused by random noises but also spatially nonuniform biases in radar rainfall at individual rain-gauge stations.In this study,a real-time adjustment to the radar reflectivity-rainfall rates (Z R) relationship scheme and the gauge-corrected,radar-based,estimation scheme with inverse distance weighting interpolation was developed.Based on the characteristics of the two schemes,the two-step correction technique of radar quantitative precipitation estimation is proposed.To minimize the errors between radar quantitative precipitation estimations and rain gauge observations,a real-time adjustnent to the Z-R relationship scheme is used to remove systematic bias on the time-domain.The gauge-corrected,radar-based,estination scheme is then used to eliminate non-uniform errors in space.Based on radar data and rain gauge observations near the Huaihe River,the two-step correction technique was evaluated using two heavy-precipitation events.The results show that the proposed scheme improved not only in the underestination of rainfall but also reduced the root-mean-square error and the mean relative error of radar-rain gauge pairs.

  9. Passive Target Tracking in Non-cooperative Radar System Based on Particle Filtering

    Institute of Scientific and Technical Information of China (English)

    LI Shuo; TAO Ran

    2006-01-01

    We propose a target tracking method based on particle filtering(PF) to solve the nonlinear non-Gaussian target-tracking problem in the bistatic radar systems using external radiation sources. Traditional nonlinear state estimation method is extended Kalman filtering (EKF), which is to do the first level Taylor series extension. It will cause an inaccuracy or even a scatter estimation result on condition that there is either a highly nonlinear target or a large noise square-error. Besides, Kalman filtering is the optimal resolution under a Gaussian noise assumption, and is not suitable to the non-Gaussian condition. PF is a sort of statistic filtering based on Monte Carlo simulation that is using some random samples (particles) to simulate the posterior probability density of system random variables. This method can be used in any nonlinear random system. It can be concluded through simulation that PF can achieve higher accuracy than the traditional EKF.

  10. Object Hierarchy-based Supervised Characterisation ofSynthetic Aperture Radar Sensor Images

    Directory of Open Access Journals (Sweden)

    Ish Rishabh

    2008-01-01

    Full Text Available A method of supervised characterisation of synthetic aperture radar (SAR satellite imageshas been discussed in which simple object shape features of satellite images have been usedto classify and describe the terrain types. This scheme is based on a multilevel approach inwhich objects of interest are first segmented out from the image and subsequently characterisedbased on their shape features. Once all objects have been characterised, the entire image canbe characterised. Emphasis has been laid on the hierarchical information extraction from theimage which enables greater flexibility in characterising the image and is not restricted to mereclassification. The paper also describes a method for giving relative importance among features,i.e., to give more weights to those features that are better than others in distinguishing betweencompeting classes. A method of comparing two SAR sensor images based on terrain elementspresent in the images has also been described here.

  11. CROSS-RANGE RESOLUTION OF SYNTHETIC APERTURE RADAR BASED ON DIVING MODEL

    Institute of Scientific and Technical Information of China (English)

    Sun Bing; Zhou Yinqing; Chen Jie

    2011-01-01

    This paper concentrates on the cross-range resolution of Synthetic Aperture Radar (SAR) based on diving model.In comparison to the azimuth resolution,the cross-range resolution can manifest the two-dimensional resolution ability of the imaging sensor SAR correctly.The diving model of SAR is an extended model from the conventional stripmap model,and the cross-range resolution expression is deduced from the equivalent linear frequency modulation pulses' compression.This expression points out that only the cross-range velocity component of the horizontal velocity contributes to the cross-range resolution.Also the cross-range resolution expressions and the performance of the conventional stripmap operation,squint side-look operation and beam circular-scanning operation are discussed.The cross-range resolution expression based on diving model will provide more general and more accurate reference.

  12. Trilateration-based localization algorithm for ADS-B radar systems

    Science.gov (United States)

    Huang, Ming-Shih

    Rapidly increasing growth and demand in various unmanned aerial vehicles (UAV) have pushed governmental regulation development and numerous technology research advances toward integrating unmanned and manned aircraft into the same civil airspace. Safety of other airspace users is the primary concern; thus, with the introduction of UAV into the National Airspace System (NAS), a key issue to overcome is the risk of a collision with manned aircraft. The challenge of UAV integration is global. As automatic dependent surveillance-broadcast (ADS-B) system has gained wide acceptance, additional exploitations of the radioed satellite-based information are topics of current interest. One such opportunity includes the augmentation of the communication ADS-B signal with a random bi-phase modulation for concurrent use as a radar signal for detecting other aircraft in the vicinity. This dissertation provides detailed discussion about the ADS-B radar system, as well as the formulation and analysis of a suitable non-cooperative multi-target tracking method for the ADS-B radar system using radar ranging techniques and particle filter algorithms. In order to deal with specific challenges faced by the ADS-B radar system, several estimation algorithms are studied. Trilateration-based localization algorithms are proposed due to their easy implementation and their ability to work with coherent signal sources. The centroid of three most closely spaced intersections of constant-range loci is conventionally used as trilateration estimate without rigorous justification. In this dissertation, we address the quality of trilateration intersections through range scaling factors. A number of well-known triangle centers, including centroid, incenter, Lemoine point (LP), and Fermat point (FP), are discussed in detail. To the author's best knowledge, LP was never associated with trilateration techniques. According our study, LP is proposed as the best trilateration estimator thanks to the

  13. Quantum radar

    CERN Document Server

    Lanzagorta, Marco

    2011-01-01

    This book offers a concise review of quantum radar theory. Our approach is pedagogical, making emphasis on the physics behind the operation of a hypothetical quantum radar. We concentrate our discussion on the two major models proposed to date: interferometric quantum radar and quantum illumination. In addition, this book offers some new results, including an analytical study of quantum interferometry in the X-band radar region with a variety of atmospheric conditions, a derivation of a quantum radar equation, and a discussion of quantum radar jamming.This book assumes the reader is familiar w

  14. MetaSensing's FastGBSAR: ground based radar for deformation monitoring

    Science.gov (United States)

    Rödelsperger, Sabine; Meta, Adriano

    2014-10-01

    The continuous monitoring of ground deformation and structural movement has become an important task in engineering. MetaSensing introduces a novel sensor system, the Fast Ground Based Synthetic Aperture Radar (FastGBSAR), based on innovative technologies that have already been successfully applied to airborne SAR applications. The FastGBSAR allows the remote sensing of deformations of a slope or infrastructure from up to a distance of 4 km. The FastGBSAR can be setup in two different configurations: in Real Aperture Radar (RAR) mode it is capable of accurately measuring displacements along a linear range profile, ideal for monitoring vibrations of structures like bridges and towers (displacement accuracy up to 0.01 mm). Modal parameters can be determined within half an hour. Alternatively, in Synthetic Aperture Radar (SAR) configuration it produces two-dimensional displacement images with an acquisition time of less than 5 seconds, ideal for monitoring areal structures like dams, landslides and open pit mines (displacement accuracy up to 0.1 mm). The MetaSensing FastGBSAR is the first ground based SAR instrument on the market able to produce two-dimensional deformation maps with this high acquisition rate. By that, deformation time series with a high temporal and spatial resolution can be generated, giving detailed information useful to determine the deformation mechanisms involved and eventually to predict an incoming failure. The system is fully portable and can be quickly installed on bedrock or a basement. The data acquisition and processing can be fully automated leading to a low effort in instrument operation and maintenance. Due to the short acquisition time of FastGBSAR, the coherence between two acquisitions is very high and the phase unwrapping is simplified enormously. This yields a high density of resolution cells with good quality and high reliability of the acquired deformations. The deformation maps can directly be used as input into an Early

  15. Passive Multistatic Radar Imaging using an OFDM Based Signal of Opportunity

    Science.gov (United States)

    2012-03-22

    is still continuing at this time. This current resurgence includes research in the areas of passive bistatic radar (PBR) and bistatic SAR . This... SAR imaging, bistatic /pas- sive radar, OFDM signals, and phase correction techniques explored throughout the research effort are introduced. Chapter...introduction on bistatic radar and the associated geometry differences to the monostatic case. A discussion of SAR imaging and the algorithm of

  16. Selected algorithms for measurement data processing in impulse-radar-based system for monitoring of human movements

    Science.gov (United States)

    Miękina, Andrzej; Wagner, Jakub; Mazurek, Paweł; Morawski, Roman Z.

    2016-11-01

    The importance of research on new technologies that could be employed in care services for elderly and disabled persons is highlighted. Advantages of impulse-radar sensors, when applied for non-intrusive monitoring of such persons in their home environment, are indicated. Selected algorithms for the measurement data preprocessing - viz. the algorithms for clutter suppression and echo parameter estimation, as well as for estimation of the twodimensional position of a monitored person - are proposed. The capability of an impulse-radar- based system to provide some application-specific parameters, viz. the parameters characterising the patient's health condition, is also demonstrated.

  17. Localizing Ground-Penetrating Radar

    Science.gov (United States)

    2014-11-01

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

  18. Radar Chart

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Radar Chart collection is an archived product of summarized radar data. The geographic coverage is the 48 contiguous states of the United States. These hourly...

  19. Feature-enhanced synthetic aperture radar image formation based on nonquadratic regularization.

    Science.gov (United States)

    Cetin, M; Karl, W C

    2001-01-01

    We develop a method for the formation of spotlight-mode synthetic aperture radar (SAR) images with enhanced features. The approach is based on a regularized reconstruction of the scattering field which combines a tomographic model of the SAR observation process with prior information regarding the nature of the features of interest. Compared to conventional SAR techniques, the method we propose produces images with increased resolution, reduced sidelobes, reduced speckle and easier-to-segment regions. Our technique effectively deals with the complex-valued, random-phase nature of the underlying SAR reflectivities. An efficient and robust numerical solution is achieved through extensions of half-quadratic regularization methods to the complex-valued SAR problem. We demonstrate the performance of the method on synthetic and real SAR scenes.

  20. Coherence estimation in synthetic aperture radar data based on speckle noise modeling.

    Science.gov (United States)

    López-Martínez, Carlos; Pottier, Eric

    2007-02-01

    In the past we proposed a multidimensional speckle noise model to which we now include systematic phase variation effects. This extension makes it possible to define what is believed to be a novel coherence model able to identify the different sources of bias when coherence is estimated on multidimensional synthetic radar aperture (SAR) data. On the one hand, low coherence biases are basically due to the complex additive speckle noise component of the Hermitian product of two SAR images. On the other hand, the availability of the coherence model permits us to quantify the bias due to topography when multilook filtering is considered, permitting us to establish the conditions upon which information may be estimated independently of topography. Based on the coherence model, two coherence estimation approaches, aiming to reduce the different biases, are proposed. Results with simulated and experimental polarimetric and interferometric SAR data illustrate and validate both, the coherence model and the coherence estimation algorithms.

  1. Nanostructured composites based on carbon nanotubes and epoxy resin for use as radar absorbing materials

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Valdirene Aparecida [Instituto Tecnologico de Aeronautica (ITA), Sao Jose dos Campos, SP (Brazil); Folgueras, Luiza de Castro; Candido, Geraldo Mauricio; Paula, Adriano Luiz de; Rezende, Mirabel Cerqueira, E-mail: mirabelmcr@iae.cta.br [Instituto de Aeronautica e Espaco (IAE), Sao Jose dos Campos, SP (Brazil). Div. de Materiais; Costa, Michelle Leali [Universidade Estadual Paulista Julio de Mesquita Filho (DMT/UNESP), Guaratingueta, SP (Brazil). Dept. de Materiais e Tecnologia

    2013-07-01

    Nanostructured polymer composites have opened up new perspectives for multifunctional materials. In particular, carbon nanotubes (CNTs) present potential applications in order to improve mechanical and electrical performance in composites with aerospace application. The combination of epoxy resin with multi walled carbon nanotubes results in a new functional material with enhanced electromagnetic properties. The objective of this work was the processing of radar absorbing materials based on formulations containing different quantities of carbon nanotubes in an epoxy resin matrix. To reach this objective the adequate concentration of CNTs in the resin matrix was determined. The processed structures were characterized by scanning electron microscopy, rheology, thermal and reflectivity in the frequency range of 8.2 to 12.4 GHz analyses. The microwave attenuation was up to 99.7%, using only 0.5% (w/w) of CNT, showing that these materials present advantages in performance associated with low additive concentrations (author)

  2. Dual-Channel Particle Filter Based Track-Before-Detect for Monopulse Radar

    Directory of Open Access Journals (Sweden)

    Fei Cai

    2014-01-01

    Full Text Available A particle filter based track-before-detect (PF-TBD algorithm is proposed for the monopulse high pulse repetition frequency (PRF pulse Doppler radar. The actual measurement model is adopted, in which the range is highly ambiguous and the sum and difference channels exist in parallel. A quantization method is used to approximate the point spread function to reduce the computation load. The detection decisions of the PF-TBD are fed to a binary integrator to further improve the detection performance. Simulation results show that the proposed algorithm can detect and track the low SNR target efficiently. The detection performance is improved significantly for both the single frame and the multiframe detection compared with the classical detector. A performance comparison with the PF-TBD using sum channel only is also supplied.

  3. An Icon-Based Synoptic Visualization of Fully Polarimetric Radar Data

    Directory of Open Access Journals (Sweden)

    Iain H. Woodhouse

    2012-03-01

    Full Text Available The visualization of fully polarimetric radar data is hindered by traditional remote sensing methodologies for displaying data due to the large number of parameters per pixel in such data, and the non-scalar nature of variables such as phase difference. In this paper, a new method is described that uses icons instead of image pixels to represent the image data so that polarimetric properties and geographic context can be visualized together. The icons are parameterized using the alpha-entropy decomposition of polarimetric data. The resulting image allows the following five variables to be displayed simultaneously: unpolarized power, alpha angle, polarimetric entropy, anisotropy and orientation angle. Examples are given for both airborne and laboratory-based imaging.

  4. Root-MUSIC Based Angle Estimation for MIMO Radar with Unknown Mutual Coupling

    Directory of Open Access Journals (Sweden)

    Jianfeng Li

    2014-01-01

    Full Text Available Direction of arrival (DOA estimation problem for multiple-input multiple-output (MIMO radar with unknown mutual coupling is studied, and an algorithm for the DOA estimation based on root multiple signal classification (MUSIC is proposed. Firstly, according to the Toeplitz structure of the mutual coupling matrix, output data of some specified sensors are selected to eliminate the influence of the mutual coupling. Then the reduced-dimension transformation is applied to make the computation burden lower as well as obtain a Vandermonde structure of the direction matrix. Finally, Root-MUSIC can be adopted for the angle estimation. The angle estimation performance of the proposed algorithm is better than that of estimation of signal parameters via rotational invariance techniques (ESPRIT-like algorithm and MUSIC-like algorithm. Furthermore, the proposed algorithm has lower complexity than them. The simulation results verify the effectiveness of the algorithm, and the theoretical estimation error of the algorithm is also derived.

  5. Satellite based radar interferometry to estimate large-scale soil water depletion from clay shrinkage: possibilities and limitations

    NARCIS (Netherlands)

    Brake, te B.; Hanssen, R.F.; Ploeg, van der M.J.; Rooij, de G.H.

    2013-01-01

    Satellite-based radar interferometry is a technique capable of measuring small surface elevation changes at large scales and with a high resolution. In vadose zone hydrology, it has been recognized for a long time that surface elevation changes due to swell and shrinkage of clayey soils can serve as

  6. Investigating the stratigraphy of Mare Imbrium flow emplacement with Earth-based radar

    Science.gov (United States)

    Morgan, G. A.; Campbell, B. A.; Campbell, D. B.; Hawke, B. R.

    2016-08-01

    The lunar maria are the product of extensive basaltic volcanism that flooded widespread portions of the Moon's surface. Constraining mare volcanic history therefore provides a window into the endogenic processes responsible for shaping the Moon. Due to the low magma viscosity and the associated thin nature of lava units, the majority of mare surface structures are masked and subdued by impact regolith. Subtle individual mare flow morphologies, coupled with spatial limitations in the use of crater size distributions to distinguish surface units close in age, restrict our understanding of mare stratigraphy. Earth-based 70 cm wavelength (P band) radar can reveal features beneath the regolith and highlight very subtle changes in the ilmenite content of the flows, providing a unique means to map mare units. Here we map volcanic units in Mare Imbrium using high-resolution (200 m/pixel), Earth-based P band data. Situated within the heat-producing potassium, rare earth element, and phosphorus terrane, Mare Imbrium experienced some of the most long-lived (and recent) lunar volcanism, and its surface exhibits a significant diversity of basaltic chemistry. Our investigation identifies at least four distinct stages of volcanic activity, originating from multiple sources within Imbrium. The most recent of these stages comprises extensive, yet relatively thin volcanic flow units that left remnant kipukas of older mare material distributed across much of the basin. From a future mission perspective, it may be possible to collect samples expressing a wide range in age from small areas of Mare Imbrium. Our map also places important constraints on the interpretation of the Chang'e-3 Lunar Penetrating Radar measurements.

  7. Cramer-Rao Bounds for UMTS-Based Passive Multistatic Radar

    Science.gov (United States)

    2014-01-01

    targets with passive bistatic radar,” IET Radar Sonar Navig., vol. 6, pp. 739–745, Oct. 2012. [9] D. E. Hack , L. K. Patton, A. D. Kerrick, and M. A...Committee Member, Tutorial Lecturer). He served as the Publicity Chair for the First IEEE International Conference on Waveform Diversity and Design

  8. 3D Visualization of Radar Backscattering Diagrams Based on OpenGL

    Science.gov (United States)

    Zhulina, Yulia V.

    2004-12-01

    A digital method of calculating the radar backscattering diagrams is presented. The method uses a digital model of an arbitrary scattering object in the 3D graphics package "OpenGL" and calculates the backscattered signal in the physical optics approximation. The backscattering diagram is constructed by means of rotating the object model around the radar-target line.

  9. Estimating Human Movement Parameters Using a Software Radio-based Radar

    NARCIS (Netherlands)

    Godana, B.; Barroso, A.; Leus, G.J.T.

    2011-01-01

    Radar is an attractive technology for long term monitoring of human movement as it operates remotely, can be placed behind walls and is able to monitor a large area depending on its operating parameters. A radar signal reflected off a moving person carries rich information on his or her activity pat

  10. Impact of coastal radar observability on the forecast of the track and rainfall of Typhoon Morakot (2009) using WRF-based ensemble Kalman filter data assimilation

    Science.gov (United States)

    Yue, Jian; Meng, Zhiyong; Yu, Cheng-Ku; Cheng, Lin-Wen

    2017-01-01

    This study explored the impact of coastal radar observability on the forecast of the track and rainfall of Typhoon Morakot (2009) using a WRF-based ensemble Kalman filter (EnKF) data assimilation (DA) system. The results showed that the performance of radar EnKF DA was quite sensitive to the number of radars being assimilated and the DA timing relative to the landfall of the tropical cyclone (TC). It was found that assimilating radial velocity (Vr) data from all the four operational radars during the 6 h immediately before TC landfall was quite important for the track and rainfall forecasts after the TC made landfall. The TC track forecast error could be decreased by about 43% and the 24-h rainfall forecast skill could be almost tripled. Assimilating Vr data from a single radar outperformed the experiment without DA, though with less improvement compared to the multiple-radar DA experiment. Different forecast performances were obtained by assimilating different radars, which was closely related to the first-time wind analysis increment, the location of moisture transport, the quasi-stationary rainband, and the local convergence line. However, only assimilating Vr data when the TC was farther away from making landfall might worsen TC track and rainfall forecasts. Besides, this work also demonstrated that Vr data from multiple radars, instead of a single radar, should be used for verification to obtain a more reliable assessment of the EnKF performance.

  11. Avalanche Debris Detection Using Satellite- and Drone Based Radar and Optical Remote Sensing

    Science.gov (United States)

    Eckerstorfer, M.; Malnes, E.; Vickers, H.; Solbø, S. A.; Tøllefsen, A.

    2014-12-01

    The mountainous fjord landscape in the county of Troms, around its capital Tromsø in Northern Norway is prone to high avalanche activity during the snow season. Large avalanches pose a hazard to infrastructure, such as buildings and roads, located between the steep mountainsides and the fjords. A prolonged cold spell during January and February 2014 was followed by rapid new-snow loading during March 2014, inducing a significant avalanche cycle with many spontaneous, size D4 avalanches that affected major transport veins. During and shortly after the avalanche cycle of March 2014, we obtained 11 Radarsat-2 Ultrafine mode scenes, chosen according to reported avalanche activity. We further collected four Radarsat-2 ScanSAR mode scenes and two Landsat-8 scenes covering the entire county of Troms. For one particular avalanche, we obtained a drone-based orthophoto, from which a DEM of the avalanche debris surface was derived, using structure-from-motion photogrammetry. This enabled us to calculate the debris volume accurately. We detected avalanche debris in the radar images visually, by applying two detection algorithms that make use of the increased backscatter in avalanche debris. This backscatter increase is a product of increased snow water equivalent and surface roughness, roughly of the order of 3 dB. In addition, we applied a multi-temporal approach by repeatedly detecting avalanche debris at different acquisition times, as well as a multi-sensor approach, covering similar areas with different sensors. This multi-temporal and multi-sensor approach enabled us to map the spatial extent and magnitude of the March 2014 avalanche cycle in the county Troms. With ESA's Sentinel-1 satellite, providing high-resolution, large swath radar images with a short repeat cycle, a complete avalanche record for a forecasting region could become feasible. In this first test season, we detected more than 550 avalanches that were released during a one-month period over an area of

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

    Science.gov (United States)

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

    2011-06-01

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

  13. A Semiautomated Multilayer Picking Algorithm for Ice-sheet Radar Echograms Applied to Ground-Based Near-Surface Data

    Science.gov (United States)

    Onana, Vincent De Paul; Koenig, Lora Suzanne; Ruth, Julia; Studinger, Michael; Harbeck, Jeremy P.

    2014-01-01

    Snow accumulation over an ice sheet is the sole mass input, making it a primary measurement for understanding the past, present, and future mass balance. Near-surface frequency-modulated continuous-wave (FMCW) radars image isochronous firn layers recording accumulation histories. The Semiautomated Multilayer Picking Algorithm (SAMPA) was designed and developed to trace annual accumulation layers in polar firn from both airborne and ground-based radars. The SAMPA algorithm is based on the Radon transform (RT) computed by blocks and angular orientations over a radar echogram. For each echogram's block, the RT maps firn segmented-layer features into peaks, which are picked using amplitude and width threshold parameters of peaks. A backward RT is then computed for each corresponding block, mapping the peaks back into picked segmented-layers. The segmented layers are then connected and smoothed to achieve a final layer pick across the echogram. Once input parameters are trained, SAMPA operates autonomously and can process hundreds of kilometers of radar data picking more than 40 layers. SAMPA final pick results and layer numbering still require a cursory manual adjustment to correct noncontinuous picks, which are likely not annual, and to correct for inconsistency in layer numbering. Despite the manual effort to train and check SAMPA results, it is an efficient tool for picking multiple accumulation layers in polar firn, reducing time over manual digitizing efforts. The trackability of good detected layers is greater than 90%.

  14. Improved Discrimination of Volcanic Complexes, Tectonic Features, and Regolith Properties in Mare Serenitatis from Earth-Based Radar Mapping

    Science.gov (United States)

    Campbell, Bruce A.; Hawke, B. Ray; Morgan, Gareth A.; Carter, Lynn M.; Campbell, Donald B.; Nolan, Michael

    2014-01-01

    Radar images at 70 cm wavelength show 4-5 dB variations in backscatter strength within regions of relatively uniform spectral reflectance properties in central and northern Mare Serenitatis, delineating features suggesting lava flow margins, channels, and superposition relationships. These backscatter differences are much less pronounced at 12.6 cm wavelength, consistent with a large component of the 70 cm echo arising from the rough or blocky transition zone between the mare regolith and the intact bedrock. Such deep probing is possible because the ilmenite content, which modulates microwave losses, of central Mare Serenitatis is generally low (2-3% by weight). Modeling of the radar returns from a buried interface shows that an average regolith thickness of 10m could lead to the observed shifts in 70 cm echo power with a change in TiO2 content from 2% to 3%. This thickness is consistent with estimates of regolith depth (10-15m) based on the smallest diameter for which fresh craters have obvious blocky ejecta. The 70 cm backscatter differences provide a view of mare flow-unit boundaries, channels, and lobes unseen by other remote sensing methods. A localized pyroclastic deposit associated with Rima Calippus is identified based on its low radar echo strength. Radar mapping also improves delineation of units for crater age dating and highlights a 250 km long, east-west trending feature in northern Mare Serenitatis that we suggest is a large graben flooded by late-stage mare flows.

  15. Precipitation and microphysical processes observed by three polarimetric X-band radars and ground-based instrumentation during HOPE

    Science.gov (United States)

    Xie, Xinxin; Evaristo, Raquel; Simmer, Clemens; Handwerker, Jan; Trömel, Silke

    2016-06-01

    This study presents a first analysis of precipitation and related microphysical processes observed by three polarimetric X-band Doppler radars (BoXPol, JuXPol and KiXPol) in conjunction with a ground-based network of disdrometers, rain gauges and vertically pointing micro rain radars (MRRs) during the High Definition Clouds and Precipitation for advancing Climate Prediction (HD(CP)2) Observational Prototype Experiment (HOPE) during April and May 2013 in Germany. While JuXPol and KiXPol were continuously observing the central HOPE area near Forschungszentrum Jülich at a close distance, BoXPol observed the area from a distance of about 48.5 km. MRRs were deployed in the central HOPE area and one MRR close to BoXPol in Bonn, Germany. Seven disdrometers and three rain gauges providing point precipitation observations were deployed at five locations within a 5 km × 5 km region, while three other disdrometers were collocated with the MRR in Bonn. The daily rainfall accumulation at each rain gauge/disdrometer location estimated from the three X-band polarimetric radar observations showed very good agreement. Accompanying microphysical processes during the evolution of precipitation systems were well captured by the polarimetric X-band radars and corroborated by independent observations from the other ground-based instruments.

  16. Radar Fundamentals, Presentation

    OpenAIRE

    Jenn, David

    2008-01-01

    Topics include: introduction, radar functions, antennas basics, radar range equation, system parameters, electromagnetic waves, scattering mechanisms, radar cross section and stealth, and sample radar systems.

  17. Design of a Radar Signal Simulator Based on Virtex-Ⅱ Series FPGA

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A simulation method to simulate the pseudorandom code P.M PP radar's echo signal is proposed that makes use of the pre-generated Doppler simulation data, according to the relative movement parameter of the radar and the target. It resolves the problem of the high precision distance simulation and the high speed digital shift phase. At the same time, the radar dynamic digital video frequency target signal simulator is designed. Simulation results of the critical unit and the output waveform are given. The result of the test satisfies the system's request.

  18. Optimal waveform-based clutter suppression algorithm for recursive synthetic aperture radar imaging systems

    Science.gov (United States)

    Zhu, Binqi; Gao, Yesheng; Wang, Kaizhi; Liu, Xingzhao

    2016-04-01

    A computational method for suppressing clutter and generating clear microwave images of targets is proposed in this paper, which combines synthetic aperture radar (SAR) principles with recursive method and waveform design theory, and it is suitable for SAR for special applications. The nonlinear recursive model is introduced into the SAR operation principle, and the cubature Kalman filter algorithm is used to estimate target and clutter responses in each azimuth position based on their previous states, which are both assumed to be Gaussian distributions. NP criteria-based optimal waveforms are designed repeatedly as the sensor flies along its azimuth path and are used as the transmitting signals. A clutter suppression filter is then designed and added to suppress the clutter response while maintaining most of the target response. Thus, with fewer disturbances from the clutter response, we can generate the SAR image with traditional azimuth matched filters. Our simulations show that the clutter suppression filter significantly reduces the clutter response, and our algorithm greatly improves the SINR of the SAR image based on different clutter suppression filter parameters. As such, this algorithm may be preferable for special target imaging when prior information on the target is available.

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

    Science.gov (United States)

    Sagnard, Florence; Tarel, Jean-Philippe

    2015-04-01

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

  20. Dynamic gauge adjustment of high-resolution X-band radar data for convective rain storms: Model-based evaluation against measured combined sewer overflow

    DEFF Research Database (Denmark)

    Borup, Morten; Grum, Morten; Linde, Jens Jørgen

    2016-01-01

    , well defined, 64 ha urban catchment, for nine overflow generating rain events. The dynamically adjusted radar data perform best when the aggregation period is as small as 10–20 min, in which case it performs much better than static adjusted radar data and data from rain gauges situated 2–3 km away.......Numerous studies have shown that radar rainfall estimates need to be adjusted against rain gauge measurements in order to be useful for hydrological modelling. In the current study we investigate if adjustment can improve radar rainfall estimates to the point where they can be used for modelling...... overflows from urban drainage systems, and we furthermore investigate the importance of the aggregation period of the adjustment scheme. This is done by continuously adjusting X-band radar data based on the previous 5–30 min of rain data recorded by multiple rain gauges and propagating the rainfall...

  1. Synthetic Aperture Radar Target Recognition with Feature Fusion Based on a Stacked Autoencoder.

    Science.gov (United States)

    Kang, Miao; Ji, Kefeng; Leng, Xiangguang; Xing, Xiangwei; Zou, Huanxin

    2017-01-20

    Feature extraction is a crucial step for any automatic target recognition process, especially in the interpretation of synthetic aperture radar (SAR) imagery. In order to obtain distinctive features, this paper proposes a feature fusion algorithm for SAR target recognition based on a stacked autoencoder (SAE). The detailed procedure presented in this paper can be summarized as follows: firstly, 23 baseline features and Three-Patch Local Binary Pattern (TPLBP) features are extracted. These features can describe the global and local aspects of the image with less redundancy and more complementarity, providing richer information for feature fusion. Secondly, an effective feature fusion network is designed. Baseline and TPLBP features are cascaded and fed into a SAE. Then, with an unsupervised learning algorithm, the SAE is pre-trained by greedy layer-wise training method. Capable of feature expression, SAE makes the fused features more distinguishable. Finally, the model is fine-tuned by a softmax classifier and applied to the classification of targets. 10-class SAR targets based on Moving and Stationary Target Acquisition and Recognition (MSTAR) dataset got a classification accuracy up to 95.43%, which verifies the effectiveness of the presented algorithm.

  2. Change detection in synthetic aperture radar images based on image fusion and fuzzy clustering.

    Science.gov (United States)

    Gong, Maoguo; Zhou, Zhiqiang; Ma, Jingjing

    2012-04-01

    This paper presents an unsupervised distribution-free change detection approach for synthetic aperture radar (SAR) images based on an image fusion strategy and a novel fuzzy clustering algorithm. The image fusion technique is introduced to generate a difference image by using complementary information from a mean-ratio image and a log-ratio image. In order to restrain the background information and enhance the information of changed regions in the fused difference image, wavelet fusion rules based on an average operator and minimum local area energy are chosen to fuse the wavelet coefficients for a low-frequency band and a high-frequency band, respectively. A reformulated fuzzy local-information C-means clustering algorithm is proposed for classifying changed and unchanged regions in the fused difference image. It incorporates the information about spatial context in a novel fuzzy way for the purpose of enhancing the changed information and of reducing the effect of speckle noise. Experiments on real SAR images show that the image fusion strategy integrates the advantages of the log-ratio operator and the mean-ratio operator and gains a better performance. The change detection results obtained by the improved fuzzy clustering algorithm exhibited lower error than its preexistences.

  3. Off-Grid Radar Coincidence Imaging Based on Variational Sparse Bayesian Learning

    Directory of Open Access Journals (Sweden)

    Xiaoli Zhou

    2016-01-01

    Full Text Available Radar coincidence imaging (RCI is a high-resolution staring imaging technique motivated by classical optical coincidence imaging. In RCI, sparse reconstruction methods are commonly used to achieve better imaging result, while the performance guarantee is based on the general assumption that the scatterers are located at the prediscretized grid-cell centers. However, the widely existing off-grid problem degrades the RCI performance considerably. In this paper, an algorithm based on variational sparse Bayesian learning (VSBL is developed to solve the off-grid RCI. Applying Taylor expansion, the unknown true dictionary is approximated accurately to a linear model. Then target reconstruction is reformulated as a joint sparse recovery problem that recovers three groups of sparse coefficients over three known dictionaries with the constraint of the common support shared by the groups. VSBL is then applied to solve the problem by assigning appropriate priors to the three groups of coefficients. Results of numerical experiments demonstrate that the algorithm can achieve outstanding reconstruction performance and yield superior performance both in suppressing noise and in adapting to off-grid error.

  4. Three-Dimensional Precession Feature Extraction of Ballistic Targets Based on Narrowband Radar Network

    Directory of Open Access Journals (Sweden)

    Zhao Shuang

    2017-02-01

    Full Text Available Micro-motion is a crucial feature used in ballistic target recognition. To address the problem that single-view observations cannot extract true micro-motion parameters, we propose a novel algorithm based on the narrowband radar network to extract three-dimensional precession features. First, we construct a precession model of the cone-shaped target, and as a precondition, we consider the invisible problem of scattering centers. We then analyze in detail the micro-Doppler modulation trait caused by the precession. Then, we match each scattering center in different perspectives based on the ratio of the top scattering center’s micro-Doppler frequency modulation coefficient and extract the 3D coning vector of the target by establishing associated multi-aspect equation systems. In addition, we estimate feature parameters by utilizing the correlation of the micro-Doppler frequency modulation coefficient of the three scattering centers combined with the frequency compensation method. We then calculate the coordinates of the conical point in each moment and reconstruct the 3D spatial portion. Finally, we provide simulation results to validate the proposed algorithm.

  5. Synthetic Aperture Radar Target Recognition with Feature Fusion Based on a Stacked Autoencoder

    Directory of Open Access Journals (Sweden)

    Miao Kang

    2017-01-01

    Full Text Available Feature extraction is a crucial step for any automatic target recognition process, especially in the interpretation of synthetic aperture radar (SAR imagery. In order to obtain distinctive features, this paper proposes a feature fusion algorithm for SAR target recognition based on a stacked autoencoder (SAE. The detailed procedure presented in this paper can be summarized as follows: firstly, 23 baseline features and Three-Patch Local Binary Pattern (TPLBP features are extracted. These features can describe the global and local aspects of the image with less redundancy and more complementarity, providing richer information for feature fusion. Secondly, an effective feature fusion network is designed. Baseline and TPLBP features are cascaded and fed into a SAE. Then, with an unsupervised learning algorithm, the SAE is pre-trained by greedy layer-wise training method. Capable of feature expression, SAE makes the fused features more distinguishable. Finally, the model is fine-tuned by a softmax classifier and applied to the classification of targets. 10-class SAR targets based on Moving and Stationary Target Acquisition and Recognition (MSTAR dataset got a classification accuracy up to 95.43%, which verifies the effectiveness of the presented algorithm.

  6. A wireless multifunctional radar-based displacement sensor for structural health monitoring

    Science.gov (United States)

    Rice, Jennifer A.; Li, Changzhi; Gu, Changzhan; Hernandez, Justin C.

    2011-04-01

    Wireless smart sensor technology offers many opportunities to advance infrastructure monitoring and maintenance by providing pertinent information regarding the condition of a structure at a lower cost and higher density than traditional monitoring approaches. Many civil structures, especially long-span bridges, have low fundamental response frequencies that are challenging to accurately measure with sensors that are suitable for integration with low-cost, low-profile, and power-constrained wireless sensor networks. Existing displacement sensing technology is either not practical for wireless sensor implementations, does not provide the necessary accuracy, or is simply too cost-prohibitive for dense sensor deployments. This paper presents the development and integration of an accurate, low-cost radar-based sensor for the enhancement of low-frequency vibration-based bridge monitoring and the measurement of static bridge deflections. The sensors utilize both a nonlinear vibrometer mode and an arctangent-demodulated interferometry mode to achieve sub-millimeter measurement accuracy for both periodic and non-periodic displacement. Experimental validation results are presented and discussed.

  7. Synthetic aperture radar imaging based on attributed scatter model using sparse recovery techniques

    Institute of Scientific and Technical Information of China (English)

    苏伍各; 王宏强; 阳召成

    2014-01-01

    The sparse recovery algorithms formulate synthetic aperture radar (SAR) imaging problem in terms of sparse representation (SR) of a small number of strong scatters’ positions among a much large number of potential scatters’ positions, and provide an effective approach to improve the SAR image resolution. Based on the attributed scatter center model, several experiments were performed with different practical considerations to evaluate the performance of five representative SR techniques, namely, sparse Bayesian learning (SBL), fast Bayesian matching pursuit (FBMP), smoothed l0 norm method (SL0), sparse reconstruction by separable approximation (SpaRSA), fast iterative shrinkage-thresholding algorithm (FISTA), and the parameter settings in five SR algorithms were discussed. In different situations, the performances of these algorithms were also discussed. Through the comparison of MSE and failure rate in each algorithm simulation, FBMP and SpaRSA are found suitable for dealing with problems in the SAR imaging based on attributed scattering center model. Although the SBL is time-consuming, it always get better performance when related to failure rate and high SNR.

  8. A smart radar absorber based on the phase-switched screen \\ud

    OpenAIRE

    Chambers, B; Tennant, A

    2005-01-01

    Although conventional (i.e., passive) radar absorbers are widely used for modifying the radar cross-section (RCS) of current military platforms, such absorbers may not have adequate performance to satisfy future requirements. Active absorbers, however, offer the potential to overcome the so-called Rozanov performance limit and to enable additional smart functionality such as monitoring damage, adaptive control of RCS or target appearance, identification-friend-or-foe, and absorb-while-scan. T...

  9. 3D Visualization of Radar Backscattering Diagrams Based on OpenGL

    Directory of Open Access Journals (Sweden)

    Yulia V. Zhulina

    2004-03-01

    Full Text Available A digital method of calculating the radar backscattering diagrams is presented. The method uses a digital model of an arbitrary scattering object in the 3D graphics package “OpenGL” and calculates the backscattered signal in the physical optics approximation. The backscattering diagram is constructed by means of rotating the object model around the radar-target line.

  10. Hail statistic in Western Europe based on a hyrid cell-tracking algorithm combining radar signals with hailstone observations

    Science.gov (United States)

    Fluck, Elody

    2015-04-01

    Hail statistic in Western Europe based on a hybrid cell-tracking algorithm combining radar signals with hailstone observations Elody Fluck¹, Michael Kunz¹ , Peter Geissbühler², Stefan P. Ritz² With hail damage estimated over Billions of Euros for a single event (e.g., hailstorm Andreas on 27/28 July 2013), hail constitute one of the major atmospheric risks in various parts of Europe. The project HAMLET (Hail Model for Europe) in cooperation with the insurance company Tokio Millennium Re aims at estimating hail probability, hail hazard and, combined with vulnerability, hail risk for several European countries (Germany, Switzerland, France, Netherlands, Austria, Belgium and Luxembourg). Hail signals are obtained from radar reflectivity since this proxy is available with a high temporal and spatial resolution using several hail proxies, especially radar data. The focus in the first step is on Germany and France for the periods 2005- 2013 and 1999 - 2013, respectively. In the next step, the methods will be transferred and extended to other regions. A cell-tracking algorithm TRACE2D was adjusted and applied to two dimensional radar reflectivity data from different radars operated by European weather services such as German weather service (DWD) and French weather service (Météo-France). Strong convective cells are detected by considering 3 connected pixels over 45 dBZ (Reflectivity Cores RCs) in a radar scan. Afterwards, the algorithm tries to find the same RCs in the next 5 minute radar scan and, thus, track the RCs centers over time and space. Additional information about hailstone diameters provided by ESWD (European Severe Weather Database) is used to determine hail intensity of the detected hail swaths. Maximum hailstone diameters are interpolated along and close to the individual hail tracks giving an estimation of mean diameters for the detected hail swaths. Furthermore, a stochastic event set is created by randomizing the parameters obtained from the

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

    Science.gov (United States)

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

    2016-12-01

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

  12. M-Sequence-Based Single-Chip UWB-Radar Sensor

    Science.gov (United States)

    Kmec, M.; Helbig, M.; Herrmann, R.; Rauschenbach, P.; Sachs, J.; Schilling, K.

    The article deals with a fully monolithically integrated single-chip M-sequence-based UWB-radar sensor, its architecture, selected design aspects and first measurement results performed on wafer and with packaged IC modules. The discussed chip is equipped with one transmitter and two receivers. The IC was designed and manufactured in commercially available high-performance 0.25 μm SiGe BiCMOS technology (f t = 110 GHz). Due to the combination of fast digital and broadband analogue system blocks in one chip, special emphasis has been placed on the electrical isolation of these functional structures. The manufactured IC is enclosed in a low-cost QFN (quad flat-pack no-leads) package and mounted on a PCB permitting the creation of MIMO-sensor arrays by cascading a number of modules. In spite of its relatively high complexity, the sensor head features a compact design (chip size of 2 × 1 mm2, QFN package size 5 × 5 mm2) and moderate power consumption (below 1 W at -3 V supply). The assembled transceiver chip can handle signals in the frequency range from near DC up to 18 GHz. This leads to an impulse response (IRF) of FWHD ≈ 50 ps (full width at half duration).

  13. Laser-radar-based three-dimensional sensor for teaching robot paths

    Science.gov (United States)

    Maekynen, Anssi J.; Kostamovaara, Juha T.; Myllyla, Risto A.

    1995-09-01

    Implementation and test results of a 3D sensor based on time-of-flight (TOF) laser radar are presented. A sensor capable of measuring 3D positions and orientations in a large working space is used for interactive teaching of robot paths and environments. It consists of a pointing device, a laser rangefinder, and a video tracker. The 3D position and orientation of the pointer are obtained by measuring the distance from two separate points on the pointer arm to a tracing receiver and by using the tracking-camera image for detecting the angle of the pointer on the plane that is perpendicular to the optical axis of the tracking system. The rangefinder uses a new active target operating principle, including fiber-coupled transmitters attached to the pointer arm. The distance and angle measurement accuracies were measured to be better than +/- 5 mm and +/- 5 deg in the ranges of 2.3 to 4.7 m and +/- 40 deg, respectively, using ordinary technology. The operating range is likely to be increased and the accuracy enhanced by using the latest state-of-the-art TOF rangefinding technique.

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

    Science.gov (United States)

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

    2016-05-01

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

  15. Efficient Backprojection-Based Synthetic Aperture Radar Computation with Many-Core Processors

    Directory of Open Access Journals (Sweden)

    Jongsoo Park

    2013-01-01

    Full Text Available Tackling computationally challenging problems with high efficiency often requires the combination of algorithmic innovation, advanced architecture, and thorough exploitation of parallelism. We demonstrate this synergy through synthetic aperture radar (SAR via backprojection, an image reconstruction method that can require hundreds of TFLOPS. Computation cost is significantly reduced by our new algorithm of approximate strength reduction; data movement cost is economized by software locality optimizations facilitated by advanced architecture support; parallelism is fully harnessed in various patterns and granularities. We deliver over 35 billion backprojections per second throughput per compute node on an Intel® Xeon® processor E5-2670-based cluster, equipped with Intel® Xeon Phi™ coprocessors. This corresponds to processing a 3K×3K image within a second using a single node. Our study can be extended to other settings: backprojection is applicable elsewhere including medical imaging, approximate strength reduction is a general code transformation technique, and many-core processors are emerging as a solution to energy-efficient computing.

  16. Verification measurements of the Karoo Array timing system: a laser radar based time transfer system

    Science.gov (United States)

    Siebrits, R.; Bauermeister, E.; Gamatham, R.; Adams, G.; Malan, J. A.; Burger, J. P.; Kapp, F.; Gibbon, T.; Kriel, H.; Abbott, T.

    2016-02-01

    An optical fiber based laser radar time transfer system has been developed for the 64-dish MeerKAT radiointerferometer telescope project to provide accurate atomic time to the receivers of the telescope system. This time transfer system is called the Karoo Array Timing System (KATS). Calibration of the time transfer system is essential to ensure that time is accurately transferred to the digitisers that form part of the receivers. Frequency domain reflectometry via vector network analysers is also used to verify measurements taken using time interval counters. This paper details the progress that is made in the verification measurements of the system in order to ensure that time, accurate to within a few nanoseconds of the Universal Coordinated Time (UTC, is available at the point where radio signals from astronomical sources are received. This capability enables world class transient and timing studies with a compact radio interferometer, which has inherent advantages over large single dish radio-telescopes, in observing the transient sky.

  17. Improving Weather Radar Precipitation Estimates by Combining two Types of Radars

    DEFF Research Database (Denmark)

    Nielsen, Jesper Ellerbæk; Thorndahl, Søren Liedtke; Rasmussen, Michael R.

    2014-01-01

    the two radar types achieves a radar product with both long range and high temporal resolution. It is validated that the blended radar product performs better than the individual radars based on ground observations from laser disdrometers. However, the data combination is challenged by lower performance...

  18. Separation of Intercepted Multi-Radar Signals Based on Parameterized Time-Frequency Analysis

    Science.gov (United States)

    Lu, W. L.; Xie, J. W.; Wang, H. M.; Sheng, C.

    2016-09-01

    Modern radars use complex waveforms to obtain high detection performance and low probabilities of interception and identification. Signals intercepted from multiple radars overlap considerably in both the time and frequency domains and are difficult to separate with primary time parameters. Time-frequency analysis (TFA), as a key signal-processing tool, can provide better insight into the signal than conventional methods. In particular, among the various types of TFA, parameterized time-frequency analysis (PTFA) has shown great potential to investigate the time-frequency features of such non-stationary signals. In this paper, we propose a procedure for PTFA to separate overlapped radar signals; it includes five steps: initiation, parameterized time-frequency analysis, demodulating the signal of interest, adaptive filtering and recovering the signal. The effectiveness of the method was verified with simulated data and an intercepted radar signal received in a microwave laboratory. The results show that the proposed method has good performance and has potential in electronic reconnaissance applications, such as electronic intelligence, electronic warfare support measures, and radar warning.

  19. Resemblance Coefficient Based Intrapulse Feature Extraction Approach for Radar Emitter Signals

    Institute of Scientific and Technical Information of China (English)

    ZHANGGexiang; JINWeidong; HULaizhao

    2005-01-01

    Radar emitter signal recognition plays an important role in electronic intelligence and electronic support measure systems. To enhance accurate recognition rate of advanced radar emitter signals to meet the requirement of modern electronic warfare, Resemblance coefficient (RC) approach is proposed to extract features from radar emitter signals with different intrapulse modulation laws. Definition of RC is given. Properties and advantages of RC are analyzed. Feature extraction algorithm using RC is described in detail. The noise-suppression performances of RC features are also analyzed. Subsequently, neural networks are used to design classifiers. Because RC contains the change and distribution information of amplitude, phase and frequency of radar emitter signals, RC can reflect the intrapulse modulation laws effectively. The results of theoretical analysis and simulation experiments show that RC features have good characteristic of not being sensitive to noise. 9 radar emitter signals are chosen to make the experiment of RC feature extraction and automatic recognition. A large number of experimental results show that good accurate recognition rate can be achieved using the proposed approach. It is proved to be a valid and practical approach.

  20. Synergetic Optimization of Missile Shapes for Aerodynamic and Radar Cross-Section Performance Based on Multi- objective Evolutionary Algorithm

    Institute of Scientific and Technical Information of China (English)

    刘洪

    2004-01-01

    A multiple-objective evolutionary algorithm (MOEA) with a new Decision Making (DM) scheme for MOD of conceptual missile shapes was presented, which is contrived to determine suitable tradeoffs from Pareto optimal set using interactive preference articulation. There are two objective functions, to maximize ratio of lift to drag and to minimize radar cross-section (RCS) value. 3D computational electromagnetic solver was used to evaluate RCS, electromagnetic performance. 3D Navier-Stokes flow solver was adopted to evaluate aerodynamic performance. A flight mechanics solver was used to analyze the stability of the missile. Based on the MOEA, a synergetic optimization of missile shapes for aerodynamic and radar cross-section performance is completed. The results show that the proposed approach can be used in more complex optimization case of flight vehicles.

  1. Electromagnetic behavior of radar absorbing materials based on Ca hexaferrite modified with Co-Ti ions and doped with La

    Directory of Open Access Journals (Sweden)

    Valdirene Aparecida da Silva

    2009-06-01

    Full Text Available Radar Absorbing Materials (RAM are compounds that absorb incidental electromagnetic radiation in tuned frequencies and dissipate it as heat. Its preparation involves the adequate processing of polymeric matrices filled with compounds that act as radar absorbing centers in the microwave range. This work shows the electromagnetic evaluation of RAM based on CoTi and La doped Ca hexaferrite. Vibrating Sample Magnetization analyses show that ion substitution promoted low values for the parameters of saturation magnetization (123.65 Am2/kg and coercive field (0.07 T indicating ferrite softening. RAM samples obtained using different hexaferrite concentrations (40-80 per cent, w/w show variations in complex permeability and permittivity parameters and also in the performance of incidental radiation attenuation. Microwave attenuation values between 40 and 98 per cent were obtained.

  2. Parameter estimation for rigid body after micro-Doppler removal based on L-statistics in the radar analysis

    Institute of Scientific and Technical Information of China (English)

    Yong Wang; Jian Kang

    2015-01-01

    In traditional inverse synthetic aperture radar (ISAR) imaging of moving targets with rotational parts, the micro-Doppler (m-D) effects caused by the rotational parts influence the quality of the radar images. Recently, L. Stankovic proposed an m-D removal method based on L-statistics, which has been proved effective and simple. The algorithm can extract the m-D effects according to different behaviors of signals induced by rotational parts and rigid bodies in time-frequency (T-F) domain. However, by removing m-D effects, some useful short time Fourier transform (STFT) samples of rigid bodies are also extracted, which induces the side lobe problem of rigid bodies. A parameter estimation method for rigid bodies after m-D removal is proposed, which can accurately re-cover rigid bodies and avoid the side lobe problem by only using m-D removal. Simulations are given to validate the effectiveness of the proposed method.

  3. Quasi-Coherent Noise Jamming to LFM Radar Based on Pseudo-random Sequence Phase-modulation

    Directory of Open Access Journals (Sweden)

    N. Tai

    2015-12-01

    Full Text Available A novel quasi-coherent noise jamming method is proposed against linear frequency modulation (LFM signal and pulse compression radar. Based on the structure of digital radio frequency memory (DRFM, the jamming signal is acquired by the pseudo-random sequence phase-modulation of sampled radar signal. The characteristic of jamming signal in time domain and frequency domain is analyzed in detail. Results of ambiguity function indicate that the blanket jamming effect along the range direction will be formed when jamming signal passes through the matched filter. By flexible controlling the parameters of interrupted-sampling pulse and pseudo-random sequence, different covering distances and jamming effects will be achieved. When the jamming power is equivalent, this jamming obtains higher process gain compared with non-coherent jamming. The jamming signal enhances the detection threshold and the real target avoids being detected. Simulation results and circuit engineering implementation validate that the jamming signal covers real target effectively.

  4. A Joint Doppler Frequency Shift and DOA Estimation Algorithm Based on Sparse Representations for Colocated TDM-MIMO Radar

    Directory of Open Access Journals (Sweden)

    Tao Chen

    2014-01-01

    Full Text Available We address the problem of a new joint Doppler frequency shift (DFS and direction of arrival (DOA estimation for colocated TDM-MIMO radar that is a novel technology applied to autocruise and safety driving system in recent years. The signal model of colocated TDM-MIMO radar with few transmitter or receiver channels is depicted and “time varying steering vector” model is proved. Inspired by sparse representations theory, we present a new processing scheme for joint DFS and DOA estimation based on the new input signal model of colocated TDM-MIMO radar. An ultracomplete redundancy dictionary for angle-frequency space is founded in order to complete sparse representations of the input signal. The SVD-SR algorithm which stands for joint estimation based on sparse representations using SVD decomposition with OMP algorithm and the improved M-FOCUSS algorithm which combines the classical M-FOCUSS with joint sparse recovery spectrum are applied to the new signal model’s calculation to solve the multiple measurement vectors (MMV problem. The improved M-FOCUSS algorithm can work more robust than SVD-SR and JS-SR algorithms in the aspects of coherent signals resolution and estimation accuracy. Finally, simulation experiments have shown that the proposed algorithms and schemes are feasible and can be further applied to practical application.

  5. A novel data association scheme for LEO space debris surveillance based on a double fence radar system

    Science.gov (United States)

    Huang, Jian; Hu, Weidong; Xin, Qin; Guo, Weiwei

    2012-12-01

    The increasing amount of space debris threatens to seriously deteriorate and damage space-based instruments in Low Earth Orbit (LEO) environments. Therefore, LEO space debris surveillance systems must be developed to provide situational awareness in space and issue warnings of collisions with LEO space debris. In this paper, a double fence radar system is proposed as an emerging paradigm for LEO space debris surveillance. This system exhibits several unique and promising characteristics compared with existing surveillance systems. In this paper, we also investigate the data association scheme for LEO space debris surveillance based on a double fence radar system. We also perform a theoretical analysis of the performance of our proposed scheme. The superiority and the effectiveness of our novel data association scheme is demonstrated by experimental results. The data used in our experiments is the LEO space debris catalog produced by the North American Air Defense Command (NORAD) up to 2009, especially for scenarios with high densities of LEO space debris, which were primarily produced by the collisions between Iridium 33 and Cosmos 2251. We hope that our work will stimulate and benefit future work on LEO space debris surveillance approaches and enable construction of the double fence radar system.

  6. Application of model-based spectral analysis to wind-profiler radar observations

    Directory of Open Access Journals (Sweden)

    E. Boyer

    Full Text Available A classical way to reduce a radar’s data is to compute the spectrum using FFT and then to identify the different peak contributions. But in case an overlapping between the different echoes (atmospheric echo, clutter, hydrometeor echo. . . exists, Fourier-like techniques provide poor frequency resolution and then sophisticated peak-identification may not be able to detect the different echoes. In order to improve the number of reduced data and their quality relative to Fourier spectrum analysis, three different methods are presented in this paper and applied to actual data. Their approach consists of predicting the main frequency-components, which avoids the development of very sophisticated peak-identification algorithms. The first method is based on cepstrum properties generally used to determine the shift between two close identical echoes. We will see in this paper that this method cannot provide a better estimate than Fourier-like techniques in an operational use. The second method consists of an autoregressive estimation of the spectrum. Since the tests were promising, this method was applied to reduce the radar data obtained during two thunder-storms. The autoregressive method, which is very simple to implement, improved the Doppler-frequency data reduction relative to the FFT spectrum analysis. The third method exploits a MUSIC algorithm, one of the numerous subspace-based methods, which is well adapted to estimate spectra composed of pure lines. A statistical study of performances of this method is presented, and points out the very good resolution of this estimator in comparison with Fourier-like techniques. Application to actual data confirms the good qualities of this estimator for reducing radar’s data.

    Key words. Meteorology and atmospheric dynamics (tropical meteorology- Radio science (signal processing- General (techniques applicable in three or more fields

  7. 基于OPENGL的雷达/ARPA模拟器%Radar/ARPA Simulator Based-on OPENGL

    Institute of Scientific and Technical Information of China (English)

    陈杰; 杨神化; 曹士连

    2012-01-01

    According to the feature of radar/ARPA simulator, this paper presents some key technologies of developing the radar/ARPA simulator using OPENGL. These technologies include the storing and sparsing of terrain data, the display of the image of radar and the echo of the motioness objects. The experiental result shows that these technologies can achieve good simulation.%针对雷达/ARPA模拟器的特点,利用使用OPENGL图形库开发了雷达/ARPA模拟器,详细介绍了地形数据的表示和抽稀方法,雷达图像的显示方法和静态目标回波的产生方法,实验表明本文介绍的技术能实现较好的仿真.

  8. Net Energy, CO2 Emission and Land-Based Cost-Benefit Analyses of <em>Jatropha> em>Biodiesel: A Case Study of the Panzhihua Region of Sichuan Province in China

    Directory of Open Access Journals (Sweden)

    Xiangzheng Deng

    2012-06-01

    Full Text Available Bioenergy is currently regarded as a renewable energy source with a high growth potential. Forest-based biodiesel, with the significant advantage of not competing with grain production on cultivated land, has been considered as a promising substitute for diesel fuel by many countries, including China. Consequently, extracting biodiesel from <em>Jatropha> curcasem> has become a growing industry. However, many key issues related to the development of this industry are still not fully resolved and the prospects for this industry are complicated. The aim of this paper is to evaluate the net energy, CO2 emission, and cost efficiency of <em>Jatropha> biodiesel as a substitute fuel in China to help resolve some of the key issues by studying data from this region of China that is well suited to growing <em>Jatropha>. Our results show that: (1 <em>Jatropha> biodiesel is preferable for global warming mitigation over diesel fuel in terms of the carbon sink during <em>Jatropha> tree growth. (2 The net energy yield of <em>Jatropha> biodiesel is much lower than that of fossil fuel, induced by the high energy consumption during <em>Jatropha> plantation establishment and the conversion from seed oil to diesel fuel step. Therefore, the energy efficiencies of the production of <em>Jatropha> and its conversion to biodiesel need to be improved. (3 Due to current low profit and high risk in the study area, farmers have little incentive to continue or increase <em>Jatropha> production. (4 It is necessary to provide more subsidies and preferential policies for <em>Jatropha> plantations if this industry is to grow. It is also necessary for local government to set realistic objectives and make rational plans to choose proper sites for <em>Jatropha> biodiesel development and the work reported here should assist that effort. Future research focused on breading high-yield varieties, development of efficient field

  9. An Unbiased Unscented Transform Based Kalman Filter for 3D Radar

    Institute of Scientific and Technical Information of China (English)

    WANGGuohong; XIUJianjuan; HEYou

    2004-01-01

    As a derivative-free alternative to the Extended Kalman filter (EKF) in the framework of state estimation, the Unscented Kalman filter (UKF) has potential applications in nonlinear filtering. By noting the fact that the unscented transform is generally biased when converting the radar measurements from spherical coordinates into Cartesian coordinates, a new filtering algorithm for 3D radar, called Unbiased unscented Kalman filter (UUKF), is proposed. The new algorithm is validated by Monte Carlo simulation runs. Simulation results show that the UUKF is more effective than the UKF, EKF and the Converted measurement Kalman filter (CMKF).

  10. Coastal Ocean State Estimates and Forecasts based on HF Radar Data

    Science.gov (United States)

    Stanev, E. V.; Schulz-Stellenfleth, J.; Staneva, J.; Seemann, J.

    2012-04-01

    Coastal Observing System for Northern and Arctic Seas (COSYNA) collects near real-time HF radar data, which are used in parallel with numerical models to provide continuously state estimates and coastal ocean forecasts. The forecasting suite includes nested 3-D hydrodynamic models running in data-assimilation mode, which are forced with an up-to-date meteorological forecast data. This paper reviews a new method focussed on intra-tidal time scales combining radial surface currents measurements from three HF radars in the German Bight with a priori information from the hydrodynamic model. The example provided in this study is considered as a step towards developing new coastal ocean products.

  11. 基于数字信号处理器的雷达教学系统设计%Design of the DSP Based Radar Training System

    Institute of Scientific and Technical Information of China (English)

    谷溪; 龚少军

    2012-01-01

    Radar is one of the important navigational aids on board. Students majoring in navigation techniques are required by STCW Convention to have special training in radar operation. In view of the situation that maritime colleges usually do not have sufficient real radars for hands-on training, a DSP based radar training system is developed, which transmits radar images to computers for radar training. The system meets the requirements of the radar training course and sets a good example to colleges.%雷达是船舶重要的导航设备之一,STCW规定航海技术专业学生在校期间必须进行雷达操作的专门训练.针对航海院校真实雷达数量少训练分组率不高的现状,设计出一款基于DSP技术的雷达教学系统,实现了雷达图像的计算机传输,满足了航海院校雷达教学的需求.该系统对航海院校雷达教学具有指导意义.

  12. Improving high-resolution quantitative precipitation estimation via fusion of multiple radar-based precipitation products

    Science.gov (United States)

    Rafieeinasab, Arezoo; Norouzi, Amir; Seo, Dong-Jun; Nelson, Brian

    2015-12-01

    For monitoring and prediction of water-related hazards in urban areas such as flash flooding, high-resolution hydrologic and hydraulic modeling is necessary. Because of large sensitivity and scale dependence of rainfall-runoff models to errors in quantitative precipitation estimates (QPE), it is very important that the accuracy of QPE be improved in high-resolution hydrologic modeling to the greatest extent possible. With the availability of multiple radar-based precipitation products in many areas, one may now consider fusing them to produce more accurate high-resolution QPE for a wide spectrum of applications. In this work, we formulate and comparatively evaluate four relatively simple procedures for such fusion based on Fisher estimation and its conditional bias-penalized variant: Direct Estimation (DE), Bias Correction (BC), Reduced-Dimension Bias Correction (RBC) and Simple Estimation (SE). They are applied to fuse the Multisensor Precipitation Estimator (MPE) and radar-only Next Generation QPE (Q2) products at the 15-min 1-km resolution (Experiment 1), and the MPE and Collaborative Adaptive Sensing of the Atmosphere (CASA) QPE products at the 15-min 500-m resolution (Experiment 2). The resulting fused estimates are evaluated using the 15-min rain gauge observations from the City of Grand Prairie in the Dallas-Fort Worth Metroplex (DFW) in north Texas. The main criterion used for evaluation is that the fused QPE improves over the ingredient QPEs at their native spatial resolutions, and that, at the higher resolution, the fused QPE improves not only over the ingredient higher-resolution QPE but also over the ingredient lower-resolution QPE trivially disaggregated using the ingredient high-resolution QPE. All four procedures assume that the ingredient QPEs are unbiased, which is not likely to hold true in reality even if real-time bias correction is in operation. To test robustness under more realistic conditions, the fusion procedures were evaluated with and

  13. Modified Cramér-Rao lower bounds for joint position and velocity estimation of a Rician target in OFDM-based passive radar networks

    Science.gov (United States)

    Shi, C. G.; Salous, S.; Wang, F.; Zhou, J. J.

    2017-01-01

    Owing to the increased deployment and the favorable range and Doppler resolutions, orthogonal frequency-division multiplexing (OFDM)-based L band digital aeronautical communication system type 1 (LDACS1) stations have become attractive systems for target surveillance in passive radar applications. This paper investigates the problem of joint parameter (position and velocity) estimation of a Rician target in OFDM-based passive radar network systems with multichannel receivers placed on moving platforms, which are composed of multiple OFDM-based LDACS1 transmitters of opportunity and multiple radar receivers. The modified Cramér-Rao lower bounds (MCRLBs) on the Cartesian coordinates of target position and velocity are computed, where the received signal from the target is composed of dominant scatterer (DS) component and weak isotropic scatterers (WIS) component. Simulation results are provided to demonstrate that the target parameter estimation accuracy can be improved by exploiting the DS component. It also shows that the joint MCRLB is not only a function of the transmitted waveform parameters, target radar cross section, and signal-to-noise ratio but also a function of the relative geometry between the target and the passive radar networks. The analytical expressions of MCRLB can be utilized as a performance metric to access the target parameter estimation in OFDM-based passive radar networks in that they enable the selection of optimal transmitter-receiver pairs for target estimation.

  14. DFT-Based Closed-form Covariance Matrix and Direct Waveforms Design for MIMO Radar to Achieve Desired Beampatterns

    KAUST Repository

    Bouchoucha, Taha

    2017-01-23

    In multiple-input multiple-out (MIMO) radar, for desired transmit beampatterns, appropriate correlated waveforms are designed. To design such waveforms, conventional MIMO radar methods use two steps. In the first step, the waveforms covariance matrix, R, is synthesized to achieve the desired beampattern. While in the second step, to realize the synthesized covariance matrix, actual waveforms are designed. Most of the existing methods use iterative algorithms to solve these constrained optimization problems. The computational complexity of these algorithms is very high, which makes them difficult to use in practice. In this paper, to achieve the desired beampattern, a low complexity discrete-Fourier-transform based closed-form covariance matrix design technique is introduced for a MIMO radar. The designed covariance matrix is then exploited to derive a novel closed-form algorithm to directly design the finite-alphabet constant-envelope waveforms for the desired beampattern. The proposed technique can be used to design waveforms for large antenna array to change the beampattern in real time. It is also shown that the number of transmitted symbols from each antenna depends on the beampattern and is less than the total number of transmit antenna elements.

  15. Wall parameters estimation based onsupport vector regression for through wall radar sensing

    Science.gov (United States)

    Chen, Xi; Chen, Weidong

    2015-12-01

    In through wall radar sensing, the wall parameters estimation (WPE) problem has been a topic that attracts a lot of attention since the wall parameters, i.e., the permittivity and the thickness, are of crucial importance to locate the targets and to produce a well-focused image, but they are usually unknown in practice. To solve this problem, in this paper, the support vector regression (SVR), a powerful tool for regression analysis, is introduced, and its performance on WPE, provided it is used it in the regular way, is investigated. Unfortunately, it is shown that the regular use of SVR cannot afford satisfactory estimation results since the sample data used in SVR, namely the received echoes from the walls, are seriously interfered with the echoes from the targets which are located near the walls. In view of this limitation, a novel SVR-based WPE approach that consists of three stages is proposed by this paper. In the first stage, three regression functions are trained by SVR, one of which will output the estimate of the permittivity in the second stage, and the others are designed to output two instrumental variables for estimating the thickness. In the third stage, the estimate of thickness will be achieved by minimizing a predefined cost function wherein the estimated permittivity and the outputted instrumental variables are involved. The better robustness and higher estimation accuracy of the proposed approach compared to the regular use of SVR are validated by the numerical experimental results using finite-difference time-domain simulations.

  16. Comparison of Ground- and Space-based Radar Observations with Disdrometer Measurements During the PECAN Field Campaign

    Science.gov (United States)

    Torres, A. D.; Rasmussen, K. L.; Bodine, D. J.; Dougherty, E.

    2015-12-01

    Plains Elevated Convection At Night (PECAN) was a large field campaign that studied nocturnal mesoscale convective systems (MCSs), convective initiation, bores, and low-level jets across the central plains in the United States. MCSs are responsible for over half of the warm-season precipitation across the central U.S. plains. The rainfall from deep convection of these systems over land have been observed to be underestimated by satellite radar rainfall-retrieval algorithms by as much as 40 percent. These algorithms have a strong dependence on the generally unmeasured rain drop-size distribution (DSD). During the campaign, our group measured rainfall DSDs, precipitation fall velocities, and total precipitation in the convective and stratiform regions of MCSs using Ott Parsivel optical laser disdrometers. The disdrometers were co-located with mobile pod units that measured temperature, wind, and relative humidity for quality control purposes. Data from the operational NEXRAD radar in LaCrosse, Wisconsin and space-based radar measurements from a Global Precipitation Measurement satellite overpass on July 13, 2015 were used for the analysis. The focus of this study is to compare DSD measurements from the disdrometers to radars in an effort to reduce errors in existing rainfall-retrieval algorithms. The error analysis consists of substituting measured DSDs into existing quantitative precipitation estimation techniques (e.g. Z-R relationships and dual-polarization rain estimates) and comparing these estimates to ground measurements of total precipitation. The results from this study will improve climatological estimates of total precipitation in continental convection that are used in hydrological studies, climate models, and other applications.

  17. Radar techniques using array antennas

    CERN Document Server

    Wirth, Wulf-Dieter

    2013-01-01

    Radar Techniques Using Array Antennas is a thorough introduction to the possibilities of radar technology based on electronic steerable and active array antennas. Topics covered include array signal processing, array calibration, adaptive digital beamforming, adaptive monopulse, superresolution, pulse compression, sequential detection, target detection with long pulse series, space-time adaptive processing (STAP), moving target detection using synthetic aperture radar (SAR), target imaging, energy management and system parameter relations. The discussed methods are confirmed by simulation stud

  18. Investigation of laser radar systems based on mid-infrared semiconductor lasers

    Science.gov (United States)

    Rybaltowski, Adam

    This dissertation deals with the possibility of utilizing mid-infrared semiconductor lasers in systems of optical remote sensing with range resolution, called laser radar or lidar. The main subject investigated in this dissertation is two-fold: firstly, an analysis of the signal-to-noise ratio (SNR) and related maximum sensing range calculations in this type of lidar based on available system components, and---secondly---improvements in the Random-Modulation Continuous-Wave (RM-CW) lidar technique to better utilize available mid-infrared semiconductor lasers. As far as the SNR analysis is concerned, an appropriate framework has been constructed to analyze post-demodulation noise in mid-infrared direct-detection RM-CW lidar. It is based on a generalization of the Wiener-Khintchine theorem; noise is assumed to be additive, stationary, and have an arbitrary power spectrum. This is in contrast to the SNR analysis in the literature on this subject, which is inadequate for mid-infrared RM-CW lidar as it only considers Poissonian fluctuations of the number of detected photons. In addition to regular SNR analysis, the framework derived in this dissertation allows treatment of singularities such as demodulation with an unbalanced sequence in 1/f noise. To calculate maximum lidar sensing range, the following detection limits have been considered: signal shot noise, background blackbody radiation shot noise based on the Background-Limited Photodetection (BLIP) detectivity limit, and minimum-size detector noise given by diffraction-limited focusing. The latter is found to be of greatest practical interest. Furthermore, a lidar figure of merit has been introduced, and all quantities related to lidar performance and its detection limits have been presented graphically. Since pseudo-random sequences discussed in the literature have been found highly non-optimal for most applications of RM-CW lidar, a framework for the construction of new pseudo-random sequences of desired

  19. HF Radar Signal Processing Based on Tomographic Imaging and CS Technique

    Directory of Open Access Journals (Sweden)

    Qiang Yang

    2014-01-01

    Full Text Available This study presents the application of a spotlight-mode synthetic aperture radar (SAR imaging technique to the problem of high probablity target detection in high frequency (HF radar system, attempting to improve its spatial resolution. The effects of finite aperture on resolution, sampling constraints and reconstruction over a complete angular range of 360 degrees are discussed. A Convolution Back Projection (CBP algorithm has been applied to image reconstruction. In order to solve the range limitation of aspect angle with one radar-carrying platform, we collect data over a larger azimuthal range by making multi-aspect observations. Each straight line is a sub aperture over which we can perform the CBP algorithm. When we demand higher resolution for stationary target, it will cause blur with longer data acquisition time. Thus the application of the traditional imaging algorithm is limited. Compressed Sensing (CS has recently attracted much interest as it can reduce the number of samples without compromising the imaging quality. Within this motivation, we discuss the applicability of CS and present the application constraint for HF radar system.

  20. Measurements of Internal Waves in the Strait of Gibraltar Using a Shore-Based Radar.

    Science.gov (United States)

    1986-01-01

    Gregorio Parrilla, Instituto Espanol de Oceanografia , for the tide gauge data from Algeciras and Tarifa. T. H. Kinder was funded by the Office of Naval...the In- measurements made at the Windmill Hill Radar Station stituto Espanol de Oceanografia for Algeciras and Tarifa 410 during the period 22-24

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

    DEFF Research Database (Denmark)

    Lenler-Eriksen, Hans-Rudolph; Meincke, Peter

    2005-01-01

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

  2. Synthetic Aperture Radar - Hardware Development

    Directory of Open Access Journals (Sweden)

    V. Rosner

    2009-06-01

    Full Text Available Experimental real and synthetic aperture radar are developed from the base-band digital unit to the analogue RF parts, based on solid state units, using pulse compression for radar imaging. Proper QPSK code is found for matched filter.

  3. Use of Borehole-Radar Methods to Monitor a Steam-Enhanced Remediation Pilot Study at a Quarry at the Former Loring Air Force Base, Maine

    Science.gov (United States)

    Gregoire, Colette; Joesten, Peter K.; Lane, Jr., John W.

    2007-01-01

    Single-hole radar reflection and crosshole radar tomography surveys were used in conjunction with conventional borehole-geophysical methods to evaluate the effectiveness of borehole-radar methods for monitoring the movement of steam and heat through fractured bedrock. The U.S. Geological Survey, in cooperation with U.S. Environmental Protection Agency (USEPA), conducted surveys in an abandoned limestone quarry at the former Loring Air Force Base during a field-scale, steam-enhanced remediation (SER) pilot project conducted by the USEPA, the U.S. Air Force, and the Maine Department of Environmental Protection to study the viability of SER to remediate non-aqueous phase liquid contamination in fractured bedrock. Numerical modeling and field experiments indicate that borehole-radar methods have the potential to monitor the presence of steam and to measure large temperature changes in the limestone matrix during SER operations. Based on modeling results, the replacement of water by steam in fractures should produce a decrease in radar reflectivity (amplitude of the reflected wave) by a factor of 10 and a change in reflection polarity. In addition, heating the limestone matrix should increase the bulk electrical conductivity and decrease the bulk dielectric permittivity. These changes result in an increase in radar attenuation and an increase in radar-wave propagation velocity, respectively. Single-hole radar reflection and crosshole radar tomography data were collected in two boreholes using 100-megahertz antennas before the start of steam injection, about 10 days after the steam injection began, and 2 months later, near the end of the injection. Fluid temperature logs show that the temperature of the fluid in the boreholes increased by 10?C (degrees Celsius) in one borehole and 40?C in the other; maximum temperatures were measured near the bottom of the boreholes. The results of the numerical modeling were used to interpret the borehole-radar data. Analyses of the

  4. Um estudo de aplicação do Radar da inovação: o grau de inovação organizacional em uma empresa de pequeno porte do setor Metal-mecânico

    Directory of Open Access Journals (Sweden)

    Breno Jose Burgos Paredes

    2014-03-01

    Full Text Available Estudos apontam que o esforço realizado para mensurar o grau de inovação em uma organização não é uma tarefa fácil, uma vez que não existe um consenso acerca do modelo mais apropriado para aplicação. Em caso específico sobre mensuração do grau de inovação em empresas participantes do Programa Agentes Locais de Inovação (ALI do SEBRAE, vem sendo aplicado um modelo de diagnóstico chamado Radar da Inovação. Nesse sentido, este artigo analisou o grau de inovação de uma Empresa de Pequeno Porte (EPP do setor metal-mecânico, localizada na Região Metropolitana de Recife-PE, a partir da aplicação do Radar da Inovação. Para tanto, o referido Radar foi realizado em três momentos distintos, com o intuito de verificar a evolução do grau de inovação organizacional. Para a fundamentação teórica, foi feita uma pesquisa bibliográfica a respeito de inovação em empresas e modelos de mensuração de grau de inovação. Os principais resultados apontaram que, a partir dos diagnósticos aplicados, foi possível sugerir ações inovadoras à EPP, como o desenvolvimento de logotipo e constituição de uma identidade visual, identificação dos principais gargalos na gestão da empresa, criação de novos canais de comunicação com o cliente e elaboração de estratégias para otimizar e padronizar os processos administrativos. 

  5. A Pedestrian Detection Scheme Using a Coherent Phase Difference Method Based on 2D Range-Doppler FMCW Radar

    Science.gov (United States)

    Hyun, Eugin; Jin, Young-Seok; Lee, Jong-Hun

    2016-01-01

    For an automotive pedestrian detection radar system, fast-ramp based 2D range-Doppler Frequency Modulated Continuous Wave (FMCW) radar is effective for distinguishing between moving targets and unwanted clutter. However, when a weak moving target such as a pedestrian exists together with strong clutter, the pedestrian may be masked by the side-lobe of the clutter even though they are notably separated in the Doppler dimension. To prevent this problem, one popular solution is the use of a windowing scheme with a weighting function. However, this method leads to a spread spectrum, so the pedestrian with weak signal power and slow Doppler may also be masked by the main-lobe of clutter. With a fast-ramp based FMCW radar, if the target is moving, the complex spectrum of the range- Fast Fourier Transform (FFT) is changed with a constant phase difference over ramps. In contrast, the clutter exhibits constant phase irrespective of the ramps. Based on this fact, in this paper we propose a pedestrian detection for highly cluttered environments using a coherent phase difference method. By detecting the coherent phase difference from the complex spectrum of the range-FFT, we first extract the range profile of the moving pedestrians. Then, through the Doppler FFT, we obtain the 2D range-Doppler map for only the pedestrian. To test the proposed detection scheme, we have developed a real-time data logging system with a 24 GHz FMCW transceiver. In laboratory tests, we verified that the signal processing results from the proposed method were much better than those expected from the conventional 2D FFT-based detection method. PMID:26805835

  6. A Pedestrian Detection Scheme Using a Coherent Phase Difference Method Based on 2D Range-Doppler FMCW Radar

    Directory of Open Access Journals (Sweden)

    Eugin Hyun

    2016-01-01

    Full Text Available For an automotive pedestrian detection radar system, fast-ramp based 2D range-Doppler Frequency Modulated Continuous Wave (FMCW radar is effective for distinguishing between moving targets and unwanted clutter. However, when a weak moving target such as a pedestrian exists together with strong clutter, the pedestrian may be masked by the side-lobe of the clutter even though they are notably separated in the Doppler dimension. To prevent this problem, one popular solution is the use of a windowing scheme with a weighting function. However, this method leads to a spread spectrum, so the pedestrian with weak signal power and slow Doppler may also be masked by the main-lobe of clutter. With a fast-ramp based FMCW radar, if the target is moving, the complex spectrum of the range- Fast Fourier Transform (FFT is changed with a constant phase difference over ramps. In contrast, the clutter exhibits constant phase irrespective of the ramps. Based on this fact, in this paper we propose a pedestrian detection for highly cluttered environments using a coherent phase difference method. By detecting the coherent phase difference from the complex spectrum of the range-FFT, we first extract the range profile of the moving pedestrians. Then, through the Doppler FFT, we obtain the 2D range-Doppler map for only the pedestrian. To test the proposed detection scheme, we have developed a real-time data logging system with a 24 GHz FMCW transceiver. In laboratory tests, we verified that the signal processing results from the proposed method were much better than those expected from the conventional 2D FFT-based detection method.

  7. A Pedestrian Detection Scheme Using a Coherent Phase Difference Method Based on 2D Range-Doppler FMCW Radar.

    Science.gov (United States)

    Hyun, Eugin; Jin, Young-Seok; Lee, Jong-Hun

    2016-01-20

    For an automotive pedestrian detection radar system, fast-ramp based 2D range-Doppler Frequency Modulated Continuous Wave (FMCW) radar is effective for distinguishing between moving targets and unwanted clutter. However, when a weak moving target such as a pedestrian exists together with strong clutter, the pedestrian may be masked by the side-lobe of the clutter even though they are notably separated in the Doppler dimension. To prevent this problem, one popular solution is the use of a windowing scheme with a weighting function. However, this method leads to a spread spectrum, so the pedestrian with weak signal power and slow Doppler may also be masked by the main-lobe of clutter. With a fast-ramp based FMCW radar, if the target is moving, the complex spectrum of the range- Fast Fourier Transform (FFT) is changed with a constant phase difference over ramps. In contrast, the clutter exhibits constant phase irrespective of the ramps. Based on this fact, in this paper we propose a pedestrian detection for highly cluttered environments using a coherent phase difference method. By detecting the coherent phase difference from the complex spectrum of the range-FFT, we first extract the range profile of the moving pedestrians. Then, through the Doppler FFT, we obtain the 2D range-Doppler map for only the pedestrian. To test the proposed detection scheme, we have developed a real-time data logging system with a 24 GHz FMCW transceiver. In laboratory tests, we verified that the signal processing results from the proposed method were much better than those expected from the conventional 2D FFT-based detection method.

  8. Radar signal analysis of ballistic missile with micro-motion based on time-frequency distribution

    Science.gov (United States)

    Wang, Jianming; Liu, Lihua; Yu, Hua

    2015-12-01

    The micro-motion of ballistic missile targets induces micro-Doppler modulation on the radar return signal, which is a unique feature for the warhead discrimination during flight. In order to extract the micro-Doppler feature of ballistic missile targets, time-frequency analysis is employed to process the micro-Doppler modulated time-varying radar signal. The images of time-frequency distribution (TFD) reveal the micro-Doppler modulation characteristic very well. However, there are many existing time-frequency analysis methods to generate the time-frequency distribution images, including the short-time Fourier transform (STFT), Wigner distribution (WD) and Cohen class distribution, etc. Under the background of ballistic missile defence, the paper aims at working out an effective time-frequency analysis method for ballistic missile warhead discrimination from the decoys.

  9. Radar micro-Doppler based human activity classification for indoor and outdoor environments

    Science.gov (United States)

    Zenaldin, Matthew; Narayanan, Ram M.

    2016-05-01

    This paper presents the results of our experimental investigation into how different environments impact the classification of human motion using radar micro-Doppler (MD) signatures. The environments studied include free space, through-thewall, leaf tree foliage, and needle tree foliage. Results on presented on classification of the following three motions: crawling, walking, and jogging. The classification task was designed how to best separate these movements. The human motion data were acquired using a monostatic coherent Doppler radar operating in the C-band at 6.5 GHz from a total of six human subjects. The received signals were analyzed in the time-frequency domain using the Short-time Fourier Transform (STFT) which was used for feature extraction. Classification was performed using a Support Vector Machine (SVM) using a Radial Basis Function (RBF). Classification accuracies in the range 80-90% were achieved to separate the three movements mentioned.

  10. Angel estimation via frequency diversity of the SIAR radar based on Bayesian theory

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The orthogonal signals of multi-carrier-frequency emission and multiple antennas receipt module are used in SIAR radar.The corresponding received echo is equivalent to non-uniform spatial sampling after the frequency diversity process.As using the traditional Fourier transform will result in the target spectral with large sidelobe,the method presented in this paper firstly makes the preordering treatment for the position of the received antenna.Then,the Bayesian maximum posteriori estimation with l2-norm weighted constraint is utilized to achieve the equivalent uniform array echo.The simulations present the spectrum estimation in angle precision estimation of multiple targets under different SNRs,different virtual antenna numbers and different elevations.The estimation results confirm the advantage of SIAR radar both in array expansion and angle estimation.

  11. Measure short separation for space debris based on radar angle error measurement information

    Science.gov (United States)

    Zhang, Yao; Wang, Qiao; Zhou, Lai-jian; Zhang, Zhuo; Li, Xiao-long

    2016-11-01

    With the increasingly frequent human activities in space, number of dead satellites and space debris has increased dramatically, bring greater risks to the available spacecraft, however, the current widespread use of measuring equipment between space target has a lot of problems, such as high development costs or the limited conditions of use. To solve this problem, use radar multi-target measure error information to the space, and combining the relationship between target and the radar station point of view, building horizontal distance decoding model. By adopting improved signal quantization digit, timing synchronization and outliers processing method, improve the measurement precision, satisfies the requirement of multi-objective near distance measurements, and the using efficiency is analyzed. By conducting the validation test, test the feasibility and effectiveness of the proposed methods.

  12. Review of Ship Surveillance Technologies Based on High-Resolution Wide-Swath Synthetic Aperture Radar Imaging

    Directory of Open Access Journals (Sweden)

    Xing Xiang-wei

    2015-02-01

    Full Text Available Synthetic Aperture Radar (SAR is widely used in ship surveillance. High-Resolution Wide-Swath (HRWS SAR data are simultaneously collected, which introduces challenges and offers new research opportunities. SAR-based ship-surveillance technologies and the performance requirements of SAR systems are reviewed and summarized. Furthermore, the characteristics of HRWS SAR imaging and ship surveillance technologies are considered in tandem, and preliminary research results on ship detection, feature extraction, and classification are discussed. Finally, we point out issues to be addressed in future work.

  13. Classification of Convective and Stratiform Cells in Meteorological Radar Images Using SVM Based on a Textural Analysis

    Institute of Scientific and Technical Information of China (English)

    Abdenasser Djafri; Boualem Haddad

    2014-01-01

    This contribution deals with the discrimination between stratiform and convective cells in meteorological radar images. This study is based on a textural analysis of the latter and their classification using a support vector machine (SVM). First, we apply different textural parameters such as energy, entropy, inertia, and local homogeneity. Through this experience, we identify the different textural features of both the stratiform and convective cells. Then, we use an SVM to find the best discriminating parameter between the two types of clouds. The main goal of this work is to better apply the Palmer and Marshall Z-R relations specific to each type of precipitation.

  14. GLUE Based Uncertainty Estimation of Urban Drainage Modeling Using Weather Radar Precipitation Estimates

    DEFF Research Database (Denmark)

    Nielsen, Jesper Ellerbæk; Thorndahl, Søren Liedtke; Rasmussen, Michael R.

    2011-01-01

    the uncertainty of the weather radar rainfall input. The main findings of this work, is that the input uncertainty propagate through the urban drainage model with significant effects on the model result. The GLUE methodology is in general a usable way to explore this uncertainty although; the exact width...... of the prediction bands can be questioned, due to the subjective nature of the method. Moreover, the method also gives very useful information about the model and parameter behaviour....

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

    OpenAIRE

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

    2014-01-01

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

  16. Study on the Carbonyl Iron Powder Based Nano-Composite Radar Wave Absorbing Coatings

    Institute of Scientific and Technical Information of China (English)

    HUANG Dong-zhen; WANG Zhi-hui; LV Yan-hong; HU Chuan-xin; LI Wan-zhi; LIANG wen-ting; YAO Jun-min

    2004-01-01

    With the rapid development of stealth technique, carbonyl iron powder is regarded as an ideal radar absorbing material. In this paper, radar absorbing properties of carbonyl iron powder was investigated by using nano composite and macroscopic multi- layer composite approach. The machine- chemistry composite methods were employed during the experiment to produce nano composite absorbent. Two carbonyl iron powders named HP1, HP2 and nano powder named HP3 were employed. Absorbents were obtained by adding 10% HP3 powder with average size of 28 nm to the HP1 and HP2 carbonyl iron powders by weight respectively. By a series of composite techniques, sample plate with the radar absorbing coating was prepared. Compared with the single coating, the wave absorbing properties were significantly improved. The working band in which the wave reflectivity was less than 5 db was 4.8 ~ 18 GHz with the coating thickness of 1.0 mm. The lowest reflectivity was found to be 12.34 db at 8 GHz. The wave absorbing coating with thin thickness,broadband and strong absorbing properties was obtained.

  17. Weather Radar Stations

    Data.gov (United States)

    Department of Homeland Security — These data represent Next-Generation Radar (NEXRAD) and Terminal Doppler Weather Radar (TDWR) weather radar stations within the US. The NEXRAD radar stations are...

  18. Improving Quantitative Precipitation Estimation via Data Fusion of High-Resolution Ground-based Radar Network and CMORPH Satellite-based Product

    Science.gov (United States)

    Cifelli, R.; Chen, H.; Chandrasekar, V.; Xie, P.

    2015-12-01

    A large number of precipitation products at multi-scales have been developed based upon satellite, radar, and/or rain gauge observations. However, how to produce optimal rainfall estimation for a given region is still challenging due to the spatial and temporal sampling difference of different sensors. In this study, we develop a data fusion mechanism to improve regional quantitative precipitation estimation (QPE) by utilizing satellite-based CMORPH product, ground radar measurements, as well as numerical model simulations. The CMORPH global precipitation product is essentially derived based on retrievals from passive microwave measurements and infrared observations onboard satellites (Joyce et al. 2004). The fine spatial-temporal resolution of 0.05o Lat/Lon and 30-min is appropriate for regional hydrologic and climate studies. However, it is inadequate for localized hydrometeorological applications such as urban flash flood forecasting. Via fusion of the Regional CMORPH product and local precipitation sensors, the high-resolution QPE performance can be improved. The area of interest is the Dallas-Fort Worth (DFW) Metroplex, which is the largest land-locked metropolitan area in the U.S. In addition to an NWS dual-polarization S-band WSR-88DP radar (i.e., KFWS radar), DFW hosts the high-resolution dual-polarization X-band radar network developed by the center for Collaborative Adaptive Sensing of the Atmosphere (CASA). This talk will present a general framework of precipitation data fusion based on satellite and ground observations. The detailed prototype architecture of using regional rainfall instruments to improve regional CMORPH precipitation product via multi-scale fusion techniques will also be discussed. Particularly, the temporal and spatial fusion algorithms developed for the DFW Metroplex will be described, which utilizes CMORPH product, S-band WSR-88DP, and X-band CASA radar measurements. In order to investigate the uncertainties associated with each

  19. Digital Receiver-based Electronic Intelligence System Configuration for the Detection and Identification of Intrapulse Modulated Radar Signals

    Directory of Open Access Journals (Sweden)

    A. K. Singh

    2014-03-01

    Full Text Available An optimum electronic intelligence system configuration incorporating the state of the art technologies and achieving the highest parameter accuracies while processing the complex intrapulse modulated radar signals is presented in this paper. The system is based on the quad digital receiver, a state of the art single board solution for the detection and analysis of modern radar signals. The system consists of base line interferometry  configuration for high accuracy direction finding measurement with sector selection based on amplitude direction finding technique. Advanced signal processing algorithms with time frequency analysis are implemented in real time in field programmable gate array to extract all the basic as well as advanced parameters of frequency and phase modulations such as chirp, barker, and poly-phase (Frank, P1-P4 codes in addition to the pulse and continuous wave signals. The intercepted intrapulse modulated signal parameters have been extracted with very high accuracy and sensitivity.Defence Science Journal, 2014, 64(2, pp. 152-158. DOI: http://dx.doi.org/10.14429/dsj.64.5091

  20. Enabling compact MMIC-based frontends for millimeter-wave imaging radar and radiometry at 94 and 210 GHz

    Science.gov (United States)

    Kallfass, Ingmar; Tessmann, Axel; Leuther, Arnulf; Kuri, Michael; Riessle, Markus; Zink, Martin; Massler, Hermann; Schlechtweg, Michael; Ambacher, Oliver

    2008-10-01

    We report on MMIC-based analog frontend components for imaging radar and radiometry at high millimeter-wave frequencies. The MMICs are realized in our metamorphic HEMT technology. In W-band, the focus is on analog frontends with multi-pixel capability. A compact four-channel receiver module based on four single-chip heterodyne receiver MMICs achieves a noise figure of 4.2 dB and a conversion gain of 7 dB. A W-band five-to-one switch MMIC with less than 3.5 dB insertion loss addresses four antenna ports and uses an integrated reference termination for pixel normalization. Both components operate in a frequency range from 75 to 100 GHz, making them suitable for broadband imaging systems with high geometrical resolution. After an overview of MMIC amplifier performance over the entire millimeter-wave frequency range, we present a chip set for imaging radar at 210 GHz, comprising linear and frequency-translating circuits.

  1. Adaptive coherence estimator based on the Krylov subspace technique for airborne radar

    Institute of Scientific and Technical Information of China (English)

    Weijian Liu; Wenchong Xie; Haibo Tong; Honglin Wang; Cui Zhou; Yongliang Wang

    2015-01-01

    A novel adaptive detector for airborne radar space-time adaptive detection (STAD) in partial y homogeneous environments is proposed. The novel detector combines the numerical y stable Krylov subspace technique and diagonal loading technique, and it uses the framework of the adaptive coherence estimator (ACE). It can effectively detect a target with low sample support. Compared with its natural competitors, the novel detector has higher proba-bility of detection (PD), especial y when the number of the training data is low. Moreover, it is shown to be practical y constant false alarm rate (CFAR).

  2. An Airborne Radar Clutter Tracking Algorithm Based on Multifractal and Fuzzy C-Mean Cluster

    Institute of Scientific and Technical Information of China (English)

    Wei Zhang; Sheng-Lin Yu; Gong Zhang

    2007-01-01

    For an airborne lookdown radar, clutter power often changes dynamically about 80 dB with wide distributions as the platform moves. Therefore, clutter tracking techniques are required to guide the selection of const false alarm rate (CFAR) schemes. In this work, clutter tracking is done in image domain and an algorithm combining multifractal and fuzzy C-mean (FCM) cluster is proposed. The clutter with large dynamic distributions in power density is converted to steady distributions of multifractal exponents by the multifractal transformation with the optimum moment. Then, later, the main lobe and side lobe are tracked from the multifractal exponents by FCM clustering method.

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

    DEFF Research Database (Denmark)

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

    2013-01-01

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

  4. Characterization of Deep Internal Layers and Basal Conditions Around the WAIS Divide Drill Site by Surface-Based Radar

    Science.gov (United States)

    Laird, C. M.; Blake, W. A.; Gogineni, P. S.; Allen, C. T.; Leuschen, C. J.; Braaten, D. A.

    2008-12-01

    We used an ultra-wideband, very high frequency (120 to 300 MHz) surface-based radar to simultaneously map ice thickness, deep internal layers and the ice-bed interface around the West Antarctic Ice Sheet (WAIS) Divide deep drill site at a fine resolution. The radar was built by the Center for Remote Sensing of Ice Sheets (CReSIS) as part of the Polar Radar for Ice Sheet Measurements (PRISM) project with the main goal of developing and testing surface-operated radars to characterize ice thickness and bedrock conditions in Antarctica and Greenland. The system was fine-tuned in the field to a center frequency of 150 MHz with a bandwidth of 20 MHz to produce greater sensitivity. The survey covered a 30 km by 8 km area with 1-km line spacing along a polar stereographic grid that overlapped both the drill site and the WAIS Divide. The data have been processed for general use and are available on the CReSIS website (www.cresis.ku.edu). Echograms and digital ice thickness, bed elevation and bed reflectivity maps have been produced while analysis continues. Our major findings to date include: 1) internal layers are observed nearly continuously to 2800 m depth, as much as 500 m below the deepest previously mapped layers in this region, 2) internal layers have been detected to within 350 m of the bed, covering about 90% of the ice thickness, 3) ice thickness varies between approximately 3100 m and 3550 m over the grid and is about 3500 m at the drill site, 4) basal returns were mapped nearly continuously along grid lines and vary by more than 30 dB, indicating a wet bed at the drill site and frozen conditions elsewhere. The data will aid rigorous interpretations of the WAIS ice cores (including impurity records and the depth/age scale) and the morphology and evolution of the WAIS (mean annual accumulation rates, spatial extent, divide migration and volcanism). Fine-resolution information on deep internal layers, basal conditions and ice thickness/bed elevation will help

  5. Automatic system for radar echoes filtering based on textural features and artificial intelligence

    Science.gov (United States)

    Hedir, Mehdia; Haddad, Boualem

    2016-11-01

    Among the very popular Artificial Intelligence (AI) techniques, Artificial Neural Network (ANN) and Support Vector Machine (SVM) have been retained to process Ground Echoes (GE) on meteorological radar images taken from Setif (Algeria) and Bordeaux (France) with different climates and topologies. To achieve this task, AI techniques were associated with textural approaches. We used Gray Level Co-occurrence Matrix (GLCM) and Completed Local Binary Pattern (CLBP); both methods were largely used in image analysis. The obtained results show the efficiency of texture to preserve precipitations forecast on both sites with the accuracy of 98% on Bordeaux and 95% on Setif despite the AI technique used. 98% of GE are suppressed with SVM, this rate is outperforming ANN skills. CLBP approach associated to SVM eliminates 98% of GE and preserves precipitations forecast on Bordeaux site better than on Setif's, while it exhibits lower accuracy with ANN. SVM classifier is well adapted to the proposed application since the average filtering rate is 95-98% with texture and 92-93% with CLBP. These approaches allow removing Anomalous Propagations (APs) too with a better accuracy of 97.15% with texture and SVM. In fact, textural features associated to AI techniques are an efficient tool for incoherent radars to surpass spurious echoes.

  6. Detection of MAVs (Micro Aerial Vehicles) based on millimeter wave radar

    Science.gov (United States)

    Noetel, Denis; Johannes, Winfried; Caris, Michael; Hommes, Alexander; Stanko, Stephan

    2016-10-01

    In this paper we present two system approaches for perimeter surveillance with radar techniques focused on the detection of Micro Aerial Vehicles (MAVs). The main task of such radars is to detect movements of targets such as an individual or a vehicle approaching a facility. The systems typically cover a range of several hundred meters up to several kilometers. In particular, the capability of identifying Remotely Piloted Aircraft Systems (RPAS), which pose a growing threat on critical infrastructure areas, is of great importance nowadays. The low costs, the ease of handling and a considerable payload make them an excellent tool for unwanted surveillance or attacks. Most platforms can be equipped with all kind of sensors or, in the worst case, with destructive devices. A typical MAV is able to take off and land vertically, to hover, and in many cases to fly forward at high speed. Thus, it can reach all kinds of places in short time while the concealed operator of the MAV resides at a remote and riskless place.

  7. REVS: a radar-based enhanced vision system for degraded visual environments

    Science.gov (United States)

    Brailovsky, Alexander; Bode, Justin; Cariani, Pete; Cross, Jack; Gleason, Josh; Khodos, Victor; Macias, Gary; Merrill, Rahn; Randall, Chuck; Rudy, Dean

    2014-06-01

    Sierra Nevada Corporation (SNC) has developed an enhanced vision system utilizing fast-scanning 94 GHz radar technology to provide three-dimensional measurements of an aircraft's forward external scene topography. This threedimensional data is rendered as terrain imagery, from the pilot's perspective, on a Head-Up Display (HUD). The image provides the requisite "enhanced vision" to continue a safe approach along the flight path below the Decision Height (DH) in Instrument Meteorological Conditions (IMC) that would otherwise be cause for a missed approach. Terrain imagery is optionally fused with digital elevation model (DEM) data of terrain outside the radar field of view, giving the pilot additional situational awareness. Flight tests conducted in 2013 show that REVS™ has sufficient resolution and sensitivity performance to allow identification of requisite visual references well above decision height in dense fog. This paper provides an overview of the Enhanced Flight Vision System (EFVS) concept, of the technology underlying REVS, and a detailed discussion of the flight test results.

  8. Characteristics of the 14 April 1999 Sydney hailstorm based on ground observations, weather radar, insurance data and emergency calls

    Directory of Open Access Journals (Sweden)

    S. S. Schuster

    2005-01-01

    Full Text Available Hailstorms occur frequently in metropolitan Sydney, in the eastern Australian State of New South Wales, which is especially vulnerable due to its building exposure and geographical location. Hailstorms challenge disaster response agencies and pose a great risk for insurance companies. This study focuses on the Sydney hailstorm of 14 April 1999 – Australia's most expensive insured natural disaster, with supporting information from two other storms. Comparisons are drawn between observed hailstone sizes, radar-derived reflectivity and damage data in the form of insurance claims and emergency calls. The 'emergency response intensity' (defined by the number of emergency calls as a proportion of the total number of dwellings in a Census Collection District is a useful new measure of the storm intensity or severity experienced. The area defined by a radar reflectivity ≥55 dBZ appears to be a good approximation of the damage swath on ground. A preferred area for hail damage is located to the left side of storm paths and corresponds well with larger hailstone sizes. Merging hail cells appear to cause a substantially higher emergency response intensity, which also corresponds well to maximum hailstone sizes. A damage threshold could be identified for hailstone sizes around 2.5 cm (1 cm, based on the emergency response intensity (insurance claims. Emergency response intensity and claims costs both correlate positively with hailstone sizes. Higher claim costs also occurred in areas that experienced higher emergency response intensities.

  9. Volcanic and impact deposits of the Moon's Aristarchus Plateau: A new view from Earth-based radar images

    Science.gov (United States)

    Campbell, Bruce A.; Carter, Lynn M.; Hawke, B. Ray; Campbell, Donald B.; Ghent, Rebecca R.

    2008-02-01

    Lunar pyroclastic deposits reflect an explosive stage of thebasaltic volcanism that filled impact basins across the nearside.These fine-grained mantling layers are of interest for theirassociation with early mare volcanic processes, and as possiblesources of volatiles and other species for lunar outposts. Wepresent Earth-based radar images, at 12.6 and 70 cm wavelengths,of the pyroclastic deposit that blankets the Aristarchus Plateau.The 70 cm data reveal the outlines of a lava-flow complex thatcovers a significant portion of the plateau and appears to haveformed by spillover of magma from the large sinuous rille VallisSchröteri. The pyroclastics mantling these flows are heavilycontaminated with rocks 10 cm and larger in diameter. The 12.6cm data confirm that other areas are mantled by 20 m or lessof material, and that there are numerous patches of 2 cm andlarger rocks associated with ejecta from Aristarchus crater.Some of the radar-detected rocky debris is within the mantlingmaterial and is not evident in visible-wavelength images. Theradar data identify thick, rock-poor areas of the pyroclasticdeposit best suited for resource exploitation.

  10. Manmade target extraction based on multistage decision and its application for change detection in polarimetric synthetic aperture radar image

    Science.gov (United States)

    Cong, Runmin; Han, Ping; Li, Chongyi; He, Jiaji; Zhang, Zaiji

    2016-09-01

    Targets of interest are different in various applications in which manmade targets, such as aircraft, ships, and buildings, are given more attention. Manmade target extraction methods using synthetic aperture radar (SAR) images are designed in response to various demands, which include civil uses, business purposes, and military industries. This plays an increasingly vital role in monitoring, military reconnaissance, and precision strikes. Achieving accurate and complete results through traditional methods is becoming more challenging because of the scattered complexity of polarization in polarimetric synthetic aperture radar (PolSAR) image. A multistage decision-based method is proposed composed of power decision, dominant scattering mechanism decision, and reflection symmetry decision. In addition, the theories of polarimetric contrast enhancement, generalized Y decomposition, and maximum eigenvalue ratio are applied to assist the decision. Fully PolSAR data are adopted to evaluate and verify the approach. Experimental results show that the method can achieve an effective result with a lower false alarm rate and clear contours. Finally, on this basis, a universal framework of change detection for manmade targets is presented as an application of our method. Two sets of measured data are also used to evaluate and verify the effectiveness of the change-detection algorithm.

  11. Cross-validation Methodology between Ground and GPM Satellite-based Radar Rainfall Product over Dallas-Fort Worth (DFW) Metroplex

    Science.gov (United States)

    Chen, H.; Chandrasekar, V.; Biswas, S.

    2015-12-01

    Over the past two decades, a large number of rainfall products have been developed based on satellite, radar, and/or rain gauge observations. However, to produce optimal rainfall estimation for a given region is still challenging due to the space time variability of rainfall at many scales and the spatial and temporal sampling difference of different rainfall instruments. In order to produce high-resolution rainfall products for urban flash flood applications and improve the weather sensing capability in urban environment, the center for Collaborative Adaptive Sensing of the Atmosphere (CASA), in collaboration with National Weather Service (NWS) and North Central Texas Council of Governments (NCTCOG), has developed an urban radar remote sensing network in DFW Metroplex. DFW is the largest inland metropolitan area in the U.S., that experiences a wide range of natural weather hazards such as flash flood and hailstorms. The DFW urban remote sensing network, centered by the deployment of eight dual-polarization X-band radars and a NWS WSR-88DP radar, is expected to provide impacts-based warning and forecasts for benefit of the public safety and economy. High-resolution quantitative precipitation estimation (QPE) is one of the major goals of the development of this urban test bed. In addition to ground radar-based rainfall estimation, satellite-based rainfall products for this area are also of interest for this study. Typical example is the rainfall rate product produced by the Dual-frequency Precipitation Radar (DPR) onboard Global Precipitation Measurement (GPM) Core Observatory satellite. Therefore, cross-comparison between ground and space-based rainfall estimation is critical to building an optimal regional rainfall system, which can take advantages of the sampling differences of different sensors. This paper presents the real-time high-resolution QPE system developed for DFW urban radar network, which is based upon the combination of S-band WSR-88DP and X

  12. Psiquiatria baseada em evidências Evidence-based psychiatry

    Directory of Open Access Journals (Sweden)

    Maurício S de Lima

    2000-09-01

    Full Text Available Em psiquiatria, observa-se grande variabilidade de práticas clínicas, muitas vezes desnecessária. Essas variações podem estar relacionadas à ausência de evidência científica confiável ou ao desconhecimento das evidências de boa qualidade disponíveis. A medicina baseada em evidências (MBE é uma combinação de estratégias que busca assegurar que o cuidado individual do paciente seja baseado na melhor informação disponível, a qual deve ser incorporada à prática clínica. Neste artigo, conceitos de MBE são discutidos com relação a aspectos e desafios no tratamento de pacientes com distimia, bulimia nervosa e esquizofrenia. A partir de resultados de três revisões sistemáticas recentemente publicadas, conclui-se que a prática de psiquiatria baseada em evidências acrescenta qualidade à prática psiquiátrica tradicional.The unnecessary variability often seen in the clinical practice can be related to both the absence of reliable evidence and unawareness of the existence of good quality evidence. Evidence-Based Medicine (EBM is a set of linked strategies designed to assist clinicians in keeping themselves up-to-date with the best available evidence. Such evidence must be incorporated into the clinical practice. EBM concepts are discussed here through common aspects and challenges doctors face when treating patients with dysthymia, bulimia nervosa, and schizophrenia. In the light of some results from three systematic reviews it is concluded that Evidence-Based Psychiatry strategies, rather than replacing the traditional ones, may be a valuable tool to improving quality in a good clinical practice.

  13. A FUZZY LOGIC-BASED APPROACH FOR THE DETECTION OF FLOODED VEGETATION BY MEANS OF SYNTHETIC APERTURE RADAR DATA

    Directory of Open Access Journals (Sweden)

    V. Tsyganskaya

    2016-06-01

    Full Text Available In this paper an algorithm designed to map flooded vegetation from synthetic aperture radar (SAR imagery is introduced. The approach is based on fuzzy logic which enables to deal with the ambiguity of SAR data and to integrate multiple ancillary data containing topographical information, simple hydraulic considerations and land cover information. This allows the exclusion of image elements with a backscatter value similar to flooded vegetation, to significantly reduce misclassification errors. The flooded vegetation mapping procedure is tested on a flood event that occurred in Germany over parts of the Saale catchment on January 2011 using a time series of high resolution TerraSAR-X data covering the time interval from 2009 to 2015. The results show that the analysis of multi-temporal X-band data combined with ancillary data using a fuzzy logic-based approach permits the detection of flooded vegetation areas.

  14. a Fuzzy Logic-Based Approach for the Detection of Flooded Vegetation by Means of Synthetic Aperture Radar Data

    Science.gov (United States)

    Tsyganskaya, V.; Martinis, S.; Twele, A.; Cao, W.; Schmitt, A.; Marzahn, P.; Ludwig, R.

    2016-06-01

    In this paper an algorithm designed to map flooded vegetation from synthetic aperture radar (SAR) imagery is introduced. The approach is based on fuzzy logic which enables to deal with the ambiguity of SAR data and to integrate multiple ancillary data containing topographical information, simple hydraulic considerations and land cover information. This allows the exclusion of image elements with a backscatter value similar to flooded vegetation, to significantly reduce misclassification errors. The flooded vegetation mapping procedure is tested on a flood event that occurred in Germany over parts of the Saale catchment on January 2011 using a time series of high resolution TerraSAR-X data covering the time interval from 2009 to 2015. The results show that the analysis of multi-temporal X-band data combined with ancillary data using a fuzzy logic-based approach permits the detection of flooded vegetation areas.

  15. Unsupervised Classification of SAR Images using Hierarchical Agglomeration and EM

    NARCIS (Netherlands)

    Kayabol, K.; Krylov, V.; Zerubia, J.; Salerno, E.; Cetin, A.E.; Salvetti, O.

    2012-01-01

    We implement an unsupervised classification algorithm for high resolution Synthetic Aperture Radar (SAR) images. The foundation of algorithm is based on Classification Expectation-Maximization (CEM). To get rid of two drawbacks of EM type algorithms, namely the initialization and the model order sel

  16. Dynamic gauge adjustment of high-resolution X-band radar data for convective rain storms: Model-based evaluation against measured combined sewer overflow

    Science.gov (United States)

    Borup, Morten; Grum, Morten; Linde, Jens Jørgen; Mikkelsen, Peter Steen

    2016-08-01

    Numerous studies have shown that radar rainfall estimates need to be adjusted against rain gauge measurements in order to be useful for hydrological modelling. In the current study we investigate if adjustment can improve radar rainfall estimates to the point where they can be used for modelling overflows from urban drainage systems, and we furthermore investigate the importance of the aggregation period of the adjustment scheme. This is done by continuously adjusting X-band radar data based on the previous 5-30 min of rain data recorded by multiple rain gauges and propagating the rainfall estimates through a hydraulic urban drainage model. The model is built entirely from physical data, without any calibration, to avoid bias towards any specific type of rainfall estimate. The performance is assessed by comparing measured and modelled water levels at a weir downstream of a highly impermeable, well defined, 64 ha urban catchment, for nine overflow generating rain events. The dynamically adjusted radar data perform best when the aggregation period is as small as 10-20 min, in which case it performs much better than static adjusted radar data and data from rain gauges situated 2-3 km away.

  17. 基于压缩感知的随机噪声成像雷达%Random Noise Imaging Radar Based on Compressed Sensing

    Institute of Scientific and Technical Information of China (English)

    江海; 林月冠; 张冰尘; 洪文

    2011-01-01

    近年来提出的压缩感知(CS)理论指出可以从很少的采样点中以很大的概率准确重建原始的未知稀疏信号.该文将压缩感知与随机噪声雷达相结合,提出了基于压缩感知的随机噪声雷达,并给出了该雷达系统的基本原理框图,从理论上证明了基于压缩感知的随机噪声雷达的回波观测矩阵具有很好的等容性质,在目标场景稀疏或可以稀疏表示时,基于压缩感知的随机噪声雷达可以采集远小于常规随机噪声雷达成像所需的回波数据并能实现准确成像,最后通过仿真实验验证了该文的结论.%Recent theory of Compressed Sensing (CS) suggests that exact recovery of an unknown sparse signal can be achieved from few measurements with overwhelming probability. In this paper, CS technology is combined with random noise radar and the concept of random noise radar is proposed based on CS. The block diagram of the radar system is presented. Detailed analysis show that the sensing matrix of the random noise radar based on CS exerts good Restricted Isometry Property (RIP). Given a sparse or transform sparse target scene, the random nose radar based on CS can get high accuracy image by collecting far less amount of echo data than conventional noise radar does. Finally, in this paper, the conclusions are all demonstrated by simulation experiments.

  18. Physics-Based Predictions for Coherent Change Detection Using X-Band Synthetic Aperture Radar

    Directory of Open Access Journals (Sweden)

    Mark Preiss

    2005-12-01

    Full Text Available A theoretical model is developed to describe the interferometric coherency between pairs of SAR images of rough soil surfaces. The model is derived using a dyadic form for surface reflectivity in the Kirchhoff approximation. This permits the combination of Kirchhoff theory and spotlight synthetic aperture radar (SAR image formation theory. The resulting model is used to describe the interferometric coherency between pairs of SAR images of rough soil surfaces. The theoretical model is applied to SAR images formed before and after surface changes observed by a repeat-pass SAR system. The change in surface associated with a tyre track following vehicle passage is modelled and SAR coherency estimates are obtained. Predicted coherency distributions for both the change and no-change scenarios are used to estimate receiver operator curves for the detection of the changes using a high-resolution, X-band SAR system.

  19. Reduced complexity FFT-based DOA and DOD estimation for moving target in bistatic MIMO radar

    KAUST Repository

    Ali, Hussain

    2016-06-24

    In this paper, we consider a bistatic multiple-input multiple-output (MIMO) radar. We propose a reduced complexity algorithm to estimate the direction-of-arrival (DOA) and direction-of-departure (DOD) for moving target. We show that the calculation of parameter estimation can be expressed in terms of one-dimensional fast-Fourier-transforms which drastically reduces the complexity of the optimization algorithm. The performance of the proposed algorithm is compared with the two-dimension multiple signal classification (2D-MUSIC) and reduced-dimension MUSIC (RD-MUSIC) algorithms. It is shown by simulations, our proposed algorithm has better estimation performance and lower computational complexity compared to the 2D-MUSIC and RD-MUSIC algorithms. Moreover, simulation results also show that the proposed algorithm achieves the Cramer-Rao lower bound. © 2016 IEEE.

  20. 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.

  1. Microcontroller-based binary integrator for millimeter-wave radar experiments.

    Science.gov (United States)

    Eskelinen, Pekka; Ruoskanen, Jukka; Peltonen, Jouni

    2010-05-01

    An easily on-site reconfigurable multiple binary integrator for millimeter radar experiments has been constructed of static random access memories, an eight bit microcontroller, and high speed video operational amplifiers. The design uses a raw comparator path and two adjustable m-out-of-n chains in a wired-OR configuration. Standard high speed memories allow the use of pulse widths below 100 ns. For eight pulse repetition intervals it gives a maximum improvement of 6.6 dB for stationary low-level target echoes. The doubled configuration enhances the capability against fluctuating targets. Because of the raw comparator path, also single return pulses of relatively high amplitude are processed.

  2. Focusing Azimuth-Invariant Bistatic Synthetic Aperture Radar Data Based on a Polynomial Model

    Institute of Scientific and Technical Information of China (English)

    ZHONG Hua; LIU Xing-zhao; WANG Jun-feng

    2009-01-01

    In this paper, a focusing approach is presented to widen the use of efficient monostatic imaging algorithms for azimuth-invariant bistatic synthetic aperture radar (SAR) data. The bistatic range history is modeled by a polynomial of azimuth time. Using this model, an analytic form of the signal spectrum in the 2D frequency domain is derived, and a simple single-valued relation between the transmitter and receive ranges is established. In this way, a lot of monostatic image formation algorithms can be extended for the bistatic SAR data, and a bistatic chirp scaling algorithm is developed as an application of the new approach. This algorithm can be used to process the azimuth-invariant bistatic configuration where the transmitter and receiver platforms are moving on parallel tracks with the same velocity. In addition, some simulation results are given to demonstrate the validity of the proposed approach.

  3. Radar absorbing materials based on titanium thin film obtained by sputtering technique

    Directory of Open Access Journals (Sweden)

    Viviane Lilian Soethe

    2011-09-01

    Full Text Available Titanium thin films with nanometer thicknesses were deposited on polyethylene terephthalate (PET substrate using the triode magnetron sputtering technique. It was observed that the titanium thin film-polymeric substrate set attenuates the energy of the incident electromagnetic wave in the frequency range of 8 to 12 GHz. This result allows to consider this set as a radar absorbing material, which may be employed in automobile, telecommunication, aerospace, medical, and electroelectronic areas. Results of the reflectivity show that the attenuation depends on the thin film thickness, as a determining factor. Thin films with 25 to 100 nm thickness values show attenuation of the electromagnetic wave energy from around 20 to 50%. Analyses by Rutherford backscattering spectrometry provided information about the thickness of the thin films studied. Hall effect analyses contributed to better understand the influence of the thin film thickness on the electron mobility and consequently on absorption properties.

  4. Real-Time Radar-Based Tracking and State Estimation of Multiple Non-Conformant Aircraft

    Science.gov (United States)

    Cook, Brandon; Arnett, Timothy; Macmann, Owen; Kumar, Manish

    2017-01-01

    In this study, a novel solution for automated tracking of multiple unknown aircraft is proposed. Many current methods use transponders to self-report state information and augment track identification. While conformant aircraft typically report transponder information to alert surrounding aircraft of its state, vehicles may exist in the airspace that are non-compliant and need to be accurately tracked using alternative methods. In this study, a multi-agent tracking solution is presented that solely utilizes primary surveillance radar data to estimate aircraft state information. Main research challenges include state estimation, track management, data association, and establishing persistent track validity. In an effort to realize these challenges, techniques such as Maximum a Posteriori estimation, Kalman filtering, degree of membership data association, and Nearest Neighbor Spanning Tree clustering are implemented for this application.

  5. Three-Dimensional ISAR Imaging Method for High-Speed Targets in Short-Range Using Impulse Radar Based on SIMO Array

    Directory of Open Access Journals (Sweden)

    Xinpeng Zhou

    2016-03-01

    Full Text Available This paper proposes a three-dimensional inverse synthetic aperture radar (ISAR imaging method for high-speed targets in short-range using an impulse radar. According to the requirements for high-speed target measurement in short-range, this paper establishes the single-input multiple-output (SIMO antenna array, and further proposes a missile motion parameter estimation method based on impulse radar. By analyzing the motion geometry relationship of the warhead scattering center after translational compensation, this paper derives the receiving antenna position and the time delay after translational compensation, and thus overcomes the shortcomings of conventional translational compensation methods. By analyzing the motion characteristics of the missile, this paper estimates the missile’s rotation angle and the rotation matrix by establishing a new coordinate system. Simulation results validate the performance of the proposed algorithm.

  6. Three-Dimensional ISAR Imaging Method for High-Speed Targets in Short-Range Using Impulse Radar Based on SIMO Array.

    Science.gov (United States)

    Zhou, Xinpeng; Wei, Guohua; Wu, Siliang; Wang, Dawei

    2016-03-11

    This paper proposes a three-dimensional inverse synthetic aperture radar (ISAR) imaging method for high-speed targets in short-range using an impulse radar. According to the requirements for high-speed target measurement in short-range, this paper establishes the single-input multiple-output (SIMO) antenna array, and further proposes a missile motion parameter estimation method based on impulse radar. By analyzing the motion geometry relationship of the warhead scattering center after translational compensation, this paper derives the receiving antenna position and the time delay after translational compensation, and thus overcomes the shortcomings of conventional translational compensation methods. By analyzing the motion characteristics of the missile, this paper estimates the missile's rotation angle and the rotation matrix by establishing a new coordinate system. Simulation results validate the performance of the proposed algorithm.

  7. Target detection in pulse-Doppler radar based on multi-scanning signal integration

    Directory of Open Access Journals (Sweden)

    O. S. Neuimin

    2013-07-01

    Full Text Available Introduction. Development of multi-scanning signal integration algorithms for pulseDoppler radars which are widely used in practice is of great practical importance. Problem statement. The problem of multi-scanning signal integration measuring range and range-rate is considered. The reflected signal from a target is a distorted white noise coherent packet of radio pulses with random initial phase and known amplitude. Target detection in a sequence of radar scans is reduced to the detection of target track. Development of a two-step multi-scanning incoherent signal integration algorithm. Two-step integration method is applied to reduce the number of tracks. In the first stage the initial signals detection with a sufficiently high probability of false alarm is performed. In the second stage the tracking problem for selection target markers is solved and the multiscanning signal integration is implemented. It provides an optimal target detection solution over K surveys with low signal-to-noise ratio. Expressions for the correct target detection probability and false alarm incorporating quality track tracking are obtained. Simulation results. Analysis of the algorithm is carried out as example of the little maneuvering target detection using the statistical modeling. The methods of calculating the output threshold (the cumulative statistics are compared on it is presented. Conclusions. Increasing the number of scans (in which the integration are performed leads to a significant decreasing the probability of false alarm, which allows to increase the signal-to-noise ratio compared with the detection in a single scan up to 3.5 dB.

  8. Limitations of Radar Coordinates

    OpenAIRE

    Bini, Donato; Lusanna, Luca; Mashhoon, Bahram

    2004-01-01

    The construction of a radar coordinate system about the world line of an observer is discussed. Radar coordinates for a hyperbolic observer as well as a uniformly rotating observer are described in detail. The utility of the notion of radar distance and the admissibility of radar coordinates are investigated. Our results provide a critical assessment of the physical significance of radar coordinates.

  9. Automatic Synthetic Aperture Radar based oil spill detection and performance estimation via a semi-automatic operational service benchmark.

    Science.gov (United States)

    Singha, Suman; Vespe, Michele; Trieschmann, Olaf

    2013-08-15

    Today the health of ocean is in danger as it was never before mainly due to man-made pollutions. Operational activities show regular occurrence of accidental and deliberate oil spill in European waters. Since the areas covered by oil spills are usually large, satellite remote sensing particularly Synthetic Aperture Radar represents an effective option for operational oil spill detection. This paper describes the development of a fully automated approach for oil spill detection from SAR. Total of 41 feature parameters extracted from each segmented dark spot for oil spill and 'look-alike' classification and ranked according to their importance. The classification algorithm is based on a two-stage processing that combines classification tree analysis and fuzzy logic. An initial evaluation of this methodology on a large dataset has been carried out and degree of agreement between results from proposed algorithm and human analyst was estimated between 85% and 93% respectively for ENVISAT and RADARSAT.

  10. 大气波导对舰载及岸基雷达的影响%The effects of atmospheric duct on shipborne and shore-based radars

    Institute of Scientific and Technical Information of China (English)

    王明明; 陆敏

    2012-01-01

    大气波导是海洋大气环境的一种常见现象,这种现象使电磁波的传播超出了地球曲率的限制,从而使岸基雷达及舰载雷达受到大量的杂波干扰。针对舰载雷达及架设高度较低的岸基雷达,本文分析了大气波导现象对其探测水面及空中目标的影响,并给出了利用大气波导现象实现雷达超视距探测的基本方法。%The atmospheric duct is a common phenomenon in the atmospheric environment of the o- cean, making the electromagnetic wave travel beyond the limit of the earth curvature and causing the shipborne and shore-based radars to be subject to a lot of clutter interference. Based on the shipborne radars and the shore-based radars with lower height, the effects of the atmospheric duct on detecting the surface and air targets are analyzed, and the basic method of realizing the OTH radar detection through the atmospheric duct is given.

  11. Introduction to radar target recognition

    CERN Document Server

    Tait, P

    2006-01-01

    This new text provides an overview of the radar target recognition process and covers the key techniques being developed for operational systems. It is based on the fundamental scientific principles of high resolution radar, and explains how the techniques can be used in real systems, taking into account the characteristics of practical radar system designs and component limitations. It also addresses operational aspects, such as how high resolution modes would fit in with other functions such as detection and tracking. Mathematics is kept to a minimum and the complex techniques and issues are

  12. All-optical bandwidth-tailorable radar

    CERN Document Server

    Zou, Weiwen; Long, Xin; Zhang, Siteng; Cui, Yuanjun; Chen, Jianping

    2015-01-01

    Radar has been widely used in military, security, and rescue. Metamaterial cloak is employed in stealth targets to evade radar detection. Hence modern radar should be reconfigurable at multi-bands for detecting stealth targets, which might be realized based on microwave photonics. Here, we demonstrate an all-optical bandwidth-tailorable radar architecture. It is a coherent system utilizing one mode-locked laser for both signal generation and reception. Heterodyning of two individually filtered optical pulses that are pre-chirped via wavelength-to-time mapping generates wideband linearly-chirped radar signal. The working bands can be flexibly tailored with desired bandwidth at user-preferred carrier frequency. After modulated onto the pre-chirped optical pulse, radar echoes are time-stretched and frequency-compressed by several times. The digitization becomes much easier without loss of detection ability. We believe that the demonstration can innovate the radar's architecture with ultra-high range resolution.

  13. RADAR PPI Scope Overlay

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — RADAR PPI Scope Overlays are used to position a RADAR image over a station at the correct resolution. The archive maintains several different RADAR resolution types,...

  14. Web-based Tools for Educators: Outreach Activities of the Polar Radar for Ice Sheet Measurements (PRISM) Project

    Science.gov (United States)

    Braaten, D. A.; Holvoet, J. F.; Gogineni, S.

    2003-12-01

    The Radar Systems and Remote Sensing Laboratory at the University of Kansas (KU) has implemented extensive outreach activities focusing on Polar Regions as part of the Polar Radar for Ice Sheet Measurements (PRISM) project. The PRISM project is developing advanced intelligent remote sensing technology that involves radar systems, an autonomous rover, and communications systems to measure detailed ice sheet characteristics, and to determine bed conditions (frozen or wet) below active ice sheets in both Greenland and Antarctica. These measurements will provide a better understanding of the response of polar ice sheets to global climate change and the resulting impact the ice sheets will have on sea level rise. Many of the research and technological development aspects of the PRISM project, such as robotics, radar systems, climate change and exploration of harsh environments, can kindle an excitement and interest in students about science and technology. These topics form the core of our K-12 education and training outreach initiatives, which are designed to capture the imagination of young students, and prompt them to consider an educational path that will lead them to scientific or engineering careers. The K-12 PRISM outreach initiatives are being developed and implemented in a collaboration with the Advanced Learning Technology Program (ALTec) of the High Plains Regional Technology in Education Consortium (HPR*TEC). ALTec is associated with the KU School of Education, and is a well-established educational research center that develops and hosts web tools to enable teachers nationwide to network, collaborate, and share resources with other teachers. An example of an innovative and successful web interface developed by ALTec is called TrackStar. Teachers can use TrackStar over the Web to develop interactive, resource-based lessons (called tracks) on-line for their students. Once developed, tracks are added to the TrackStar database and can be accessed and modified

  15. Advances in bistatic radar

    CERN Document Server

    Willis, Nick

    2007-01-01

    Advances in Bistatic Radar updates and extends bistatic and multistatic radar developments since publication of Willis' Bistatic Radar in 1991. New and recently declassified military applications are documented. Civil applications are detailed including commercial and scientific systems. Leading radar engineers provide expertise to each of these applications. Advances in Bistatic Radar consists of two major sections: Bistatic/Multistatic Radar Systems and Bistatic Clutter and Signal Processing. Starting with a history update, the first section documents the early and now declassified military

  16. Modified reconstruction algorithm based on space-time adaptive processing for multichannel synthetic aperture radar systems in azimuth

    Science.gov (United States)

    Guo, Xiaojiang; Gao, Yesheng; Wang, Kaizhi; Liu, Xingzhao

    2016-07-01

    A spectrum reconstruction algorithm based on space-time adaptive processing (STAP) can effectively suppress azimuth ambiguity for multichannel synthetic aperture radar (SAR) systems in azimuth. However, the traditional STAP-based reconstruction approach has to estimate the covariance matrix and calculate matrix inversion (MI) for each Doppler frequency bin, which will result in a very large computational load. In addition, the traditional STAP-based approach has to know the exact platform velocity, pulse repetition frequency, and array configuration. Errors involving these parameters will significantly degrade the performance of ambiguity suppression. A modified STAP-based approach to solve these problems is presented. The traditional array steering vectors and corresponding covariance matrices are Doppler-variant in the range-Doppler domain. After preprocessing by a proposed phase compensation method, they would be independent of Doppler bins. Therefore, the modified STAP-based approach needs to estimate the covariance matrix and calculate MI only once. The computation load could be greatly reduced. Moreover, by combining the reconstruction method and a proposed adaptive parameter estimation method, the modified method is able to successfully achieve multichannel SAR signal reconstruction and suppress azimuth ambiguity without knowing the above parameters. Theoretical analysis and experiments showed the simplicity and efficiency of the proposed methods.

  17. Power versus performance tradeoffs of GPU-accelerated backprojection-based synthetic aperture radar image formation

    Science.gov (United States)

    Portillo, Ricardo; Arunagiri, Sarala; Teller, Patricia J.; Park, Song J.; Nguyen, Lam H.; Deroba, Joseph C.; Shires, Dale

    2011-06-01

    The continuing miniaturization and parallelization of computer hardware has facilitated the development of mobile and field-deployable systems that can accommodate terascale processing within once prohibitively small size and weight constraints. General-purpose Graphics Processing Units (GPUs) are prominent examples of such terascale devices. Unfortunately, the added computational capability of these devices often comes at the cost of larger demands on power, an already strained resource in these systems. This study explores power versus performance issues for a workload that can take advantage of GPU capability and is targeted to run in field-deployable environments, i.e., Synthetic Aperture Radar (SAR). Specifically, we focus on the Image Formation (IF) computational phase of SAR, often the most compute intensive, and evaluate two different state-of-the-art GPU implementations of this IF method. Using real and simulated data sets, we evaluate performance tradeoffs for single- and double-precision versions of these implementations in terms of time-to-solution, image output quality, and total energy consumption. We employ fine-grain direct-measurement techniques to capture isolated power utilization and energy consumption of the GPU device, and use general and radarspecific metrics to evaluate image output quality. We show that double-precision IF can provide slight image improvement to low-reflective areas of SAR images, but note that the added quality may not be worth the higher power and energy costs associated with higher precision operations.

  18. Onshore propagation of a buoyant ocean front observed using a shore-based marine radar

    Science.gov (United States)

    Marmorino, G. O.; Cooper, A. L.; Mied, R. P.; Lindemann, G. J.; Trizna, D. B.; Porter, D. L.

    2004-06-01

    An analysis is presented of a 2-h-long time series of X-band marine radar images, collected at Duck, North Carolina (USA), that captured the evolution of a buoyant ocean front as it propagated onshore, following a period of upwelling-favorable winds. In plan view, the front exhibits a scallop-shaped structure similar to that previously observed along strongly convergent fronts. This alongshore structure consists of broad frontal crests (a few hundred meters in length) alternating with sharply angled troughs, or frontal cusps. The evolution of these frontal shapes is explored using a reduced-gravity model (Cooper et al., J. Geophys. Res.-Oceans 106 (2001) 16887) that allows for nonlinear self-interaction of a propagating front. A model simulation shows cusps that develop quickly from initially broad troughs and that point toward the buoyant water, features resembling the observations. However, the simulation also shows a continuous oscillation of frontal shapes, while the observed front reaches a quasi-steady plan form. We attribute this difference in behavior to the gradual shoaling of the observed front as it steadily advances, ultimately reaching water depths of less than 2 m, which is comparable to the thickness of the buoyant layer. As a consequence of the shoaling, we suggest the cusps become sites of enhanced mixing, where water inshore of the front is also accelerated seaward.

  19. Capabilities of Earth-based Radar Facilities for Near-Earth Asteroid Observations

    Science.gov (United States)

    Naidu, Shantanu. P.; Benner, Lance. A. M.; Margot, Jean-Luc; Busch, Michael. W.; Taylor, Patrick. A.

    2016-10-01

    We evaluated the planetary radar capabilities at Arecibo, the Goldstone 70 m DSS-14 and 34 m DSS-13 antennas, the 70 m DSS-43 antenna at Canberra, the Green Bank Telescope (GBT), and the Parkes Radio Telescope in terms of their relative sensitivities and the number of known near-Earth asteroids (NEAs) detectable per year in monostatic and bistatic configurations. In the 2015 calendar year, monostatic observations with Arecibo and DSS-14 were capable of detecting 253 and 131 NEAs respectively, with signal-to-noise ratios (SNRs) greater than 30/track. Combined, the two observatories were capable of detecting 276 NEAs. Of these, Arecibo detected 77 and Goldstone detected 32, or 30% and 24% of the numbers that were possible. The two observatories detected an additional 18 and 7 NEAs respectively, with SNRs of less than 30/track. This indicates that a substantial number of potential targets are not being observed. The bistatic configuration with DSS-14 transmitting and the GBT receiving was capable of detecting about 195 NEAs, or ∼50% more than with monostatic observations at DSS-14. Most of the detectable asteroids were targets of opportunity that were discovered less than 15 days before the end of their observing windows. About 50% of the detectable asteroids have absolute magnitudes \\gt 25, which corresponds to diameters \\lt ∼ 30 m.

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

    Science.gov (United States)

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

    2009-05-01

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

  1. A parameter inversion for sea bridge based on high-resolution polarimetric synthetic aperture radar

    Institute of Scientific and Technical Information of China (English)

    LIU Genwang; ZHANG Jie; ZHANG Xi; MENG Junmin; WANG Guoyu

    2016-01-01

    Each reflection return of a bridge over water is displayed as wide stripe in a high-resolution synthetic aperture radar (SAR) image, which lead to difficulties in a parameter inversion. Therefore, a method of bridge parameter inversion is proposed for high-resolution full polarimetric SAR (PolSAR). First, the single, double and triple-bounce returns from each component of the bridge are distinguished by the polarization scattering features. Then the reasons which lead to the backscatter echoes of the bridge over water being displayed as stripes are analyzed, using a principle of microwave reflection, as well as an extraction method for each reflection return, and a parameter retrieval method is obtained. Finally, the parameters of the bridge, including the height (top and bottom surfaces of the sea bridge), width, thickness, span, and height of the bridge tower, are retrieved using full polarimetric AIRSAR data. When a comparison of the measured data is completed, the results indicate that the proposed method can invert the parameters with a high accuracy, and that the inversion error of the bridge height (bottom surface) is only 1.3%. Moreover, the results also show that for the high-resolution SAR, the C and L-band images have the same ability in regards to parameter retrieval.

  2. Capabilities of Earth-based radar facilities for near-Earth asteroid observations

    CERN Document Server

    Naidu, Shantanu P; Margot, Jean-Luc; Busch, Michael W; Taylor, Patrick A

    2016-01-01

    We evaluated the planetary radar capabilities at Arecibo, the Goldstone 70 m DSS-14 and 34-m DSS-13 antennas, the 70-m DSS-43 antenna at Canberra, the Green Bank Telescope, and the Parkes Radio Telescope in terms of their relative sensitivities and the number of known near-Earth asteroids (NEAs) detectable per year in monostatic and bistatic configurations. In the 2015 calendar year, monostatic observations with Arecibo and DSS-14 were capable of detecting 253 and 131 NEAs respectively. Combined, the two observatories were capable of detecting 276 unique NEAs. Of these, Arecibo detected 95 and Goldstone detected 39, or 38% and 30% the numbers that were possible. This indicates that a substantial number of potential targets are not being observed. The bistatic configuration with DSS-14 transmitting and the Green Bank Telescope receiving was capable of detecting about 195 NEAs, or ~50% more than with monostatic observations at DSS-14. Most of the detectable asteroids were targets-of-opportunity that were discov...

  3. Radar Observations of Asteroids

    Science.gov (United States)

    Ostro, S. J.

    2003-05-01

    During the past 25 years, radar investigations have provided otherwise unavailable information about the physical and dynamical properties of more than 200 asteroids. Measurements of the distribution of echo power in time delay and Doppler frequency provide two-dimensional images with spatial resolution as fine as a decameter. Sequences of delay-Doppler images can be used to produce geologically detailed three-dimensional models, to define the rotation state precisely, to constrain the internal density distribution, and to estimate the trajectory of the object's center of mass. Radar wavelengths (4 to 13 cm) and the observer's control of transmitted and received polarizations make the observations sensitive to near-surface bulk density and macroscopic structure. Since delay-Doppler positional measurements are orthogonal to optical angle measurements and typically have much finer fractional precision, they are powerful for refining orbits and prediction ephemerides. Radar astrometry can add decades or centuries to the interval over which an asteroid's close Earth approaches can accurately be predicted and can significantly refine collision probability estimates based on optical astrometry alone. In the highly unlikely case that a small body is on course for an Earth collision in this century, radar reconnaissance would almost immediately distinguish between an impact trajectory and a near miss and would dramatically reduce the difficulty and cost of any effort to prevent the collision. The sizes and rotation periods of radar-detected asteroids span more than four orders of magnitude. These observations have revealed both stony and metallic objects, elongated and nonconvex shapes as well as nearly featureless spheroids, small-scale morphology ranging from smoother than the lunar regolith to rougher than the rockiest terrain on Mars, craters and diverse linear structures, non-principal-axis spin states, contact binaries, and binary systems.

  4. Crop monitoring & yield forecasting system based on Synthetic Aperture Radar (SAR) and process-based crop growth model: Development and validation in South and South East Asian Countries

    Science.gov (United States)

    Setiyono, T. D.

    2014-12-01

    Accurate and timely information on rice crop growth and yield helps governments and other stakeholders adapting their economic policies and enables relief organizations to better anticipate and coordinate relief efforts in the wake of a natural catastrophe. Such delivery of rice growth and yield information is made possible by regular earth observation using space-born Synthetic Aperture Radar (SAR) technology combined with crop modeling approach to estimate yield. Radar-based remote sensing is capable of observing rice vegetation growth irrespective of cloud coverage, an important feature given that in incidences of flooding the sky is often cloud-covered. The system allows rapid damage assessment over the area of interest. Rice yield monitoring is based on a crop growth simulation and SAR-derived key information, particularly start of season and leaf growth rate. Results from pilot study sites in South and South East Asian countries suggest that incorporation of SAR data into crop model improves yield estimation for actual yields. Remote-sensing data assimilation into crop model effectively capture responses of rice crops to environmental conditions over large spatial coverage, which otherwise is practically impossible to achieve. Such improvement of actual yield estimates offers practical application such as in a crop insurance program. Process-based crop simulation model is used in the system to ensure climate information is adequately captured and to enable mid-season yield forecast.

  5. EM absorption reduction in wireless mobile antenna using printed paper-based metamaterial

    Science.gov (United States)

    Alam, Touhidul; Islam, Mohammad Tariqul; Kibria, Salehin; Cho, Mengu; Faruque, Mohammad Rashed Iqbal

    2017-01-01

    This paper presents a printed negative index metamaterial for electromagnetic (EM) absorption reduction in portable wireless antenna. The perceptible novelty exhibited in this paper is that EM absorption reduction toward the human head with paper-based metamaterial attachment. This research has been performed using human head phantom integrated in the commercially available CST Microwave Studio software package. The EM absorption has been reduced by 13.2 and 6% at 900 and 1800 MHz, respectively.

  6. Multi-DSP and FPGA based Multi-channel Direct IF/RF Digital receiver for atmospheric radar

    Science.gov (United States)

    Yasodha, Polisetti; Jayaraman, Achuthan; Kamaraj, Pandian; Durga rao, Meka; Thriveni, A.

    2016-07-01

    to DDC block, which down converts the data to base-band. The DDC block has NCO, mixer and two chains of Bessel filters (fifth order cascaded integration comb filter, two FIR filters, two half band filters and programmable FIR filters) for in-phase (I) and Quadrature phase (Q) channels. The NCO has 32 bits and is set to match the output frequency of ADC. Further, DDC down samples (decimation) the data and reduces the data rate to 16 MSPS. This data is further decimated and the data rate is reduced down to 4/2/1/0.5/0.25/0.125/0.0625 MSPS for baud lengths 0.25/0.5/1/2/4/8/16 μs respectively. The down sampled data is then fed to decoding block, which performs cross correlation to achieve pulse compression of the binary-phase coded data to obtain better range resolution with maximum possible height coverage. This step improves the signal power by a factor equal to the length of the code. Coherent integration block integrates the decoded data coherently for successive pulses, which improves the signal to noise ratio and reduces the data volume. DDC, decoding and coherent integration blocks are implemented in Xilinx vertex5 FPGA. Till this point, function of all six channels is same for DBS mode and multi-receiver modes. Data from vertex5 FPGA is transferred to PC via GbE-1 interface for multi-modes or to two Analog devices make ADSP-TS201 DSP chips (A and B), via link port for DBS mode. ADSP-TS201 chips perform the normalization, DC removal, windowing, FFT computation and spectral averaging on the data, which is transferred to storage/display PC via GbE-2 interface for real-time data display and data storing. Physical layer of GbE interface is implemented in an external chip (Marvel 88E1111) and MAC layer is implemented internal to vertex5 FPGA. The MCDRx has total 4 GB of DDR2 memory for data storage. Spartan6 FPGA is used for generating timing signals, required for basic operation of the radar and testing of the MCDRx.

  7. Detection and Identification of Multiple Stationary Human Targets Via Bio-Radar Based on the Cross-Correlation Method

    Directory of Open Access Journals (Sweden)

    Yang Zhang

    2016-10-01

    Full Text Available Ultra-wideband (UWB radar has been widely used for detecting human physiological signals (respiration, movement, etc. in the fields of rescue, security, and medicine owing to its high penetrability and range resolution. In these applications, especially in rescue after disaster (earthquake, collapse, mine accident, etc., the presence, number, and location of the trapped victims to be detected and rescued are the key issues of concern. Ample research has been done on the first issue, whereas the identification and localization of multi-targets remains a challenge. False positive and negative identification results are two common problems associated with the detection of multiple stationary human targets. This is mainly because the energy of the signal reflected from the target close to the receiving antenna is considerably stronger than those of the targets at further range, often leading to missing or false recognition if the identification method is based on the energy of the respiratory signal. Therefore, a novel method based on cross-correlation is proposed in this paper that is based on the relativity and periodicity of the signals, rather than on the energy. The validity of this method is confirmed through experiments using different scenarios; the results indicate a discernible improvement in the detection precision and identification of the multiple stationary targets.

  8. Identification-While-Scanning of a Multi-Aircraft Formation Based on Sparse Recovery for Narrowband Radar.

    Science.gov (United States)

    Jiang, Yuan; Xu, Jia; Peng, Shi-Bao; Mao, Er-Ke; Long, Teng; Peng, Ying-Ning

    2016-11-23

    It is known that the identification performance of a multi-aircraft formation (MAF) of narrowband radar mainly depends on the time on target (TOT). To realize the identification task in one rotated scan with limited TOT, the paper proposes a novel identification-while-scanning (IWS) method based on sparse recovery to maintain high rotating speed and super-resolution for MAF identification, simultaneously. First, a multiple chirp signal model is established for MAF in a single scan, where different aircraft may have different Doppler centers and Doppler rates. Second, based on the sparsity of MAF in the Doppler parameter space, a novel hierarchical basis pursuit (HBP) method is proposed to obtain satisfactory sparse recovery performance as well as high computational efficiency. Furthermore, the parameter estimation performance of the proposed IWS identification method is analyzed with respect to recovery condition, signal-to-noise ratio and TOT. It is shown that an MAF can be effectively identified via HBP with a TOT of only about one hundred microseconds for IWS applications. Finally, some numerical experiment results are provided to demonstrate the effectiveness of the proposed method based on both simulated and real measured data.

  9. Identification-While-Scanning of a Multi-Aircraft Formation Based on Sparse Recovery for Narrowband Radar

    Directory of Open Access Journals (Sweden)

    Yuan Jiang

    2016-11-01

    Full Text Available It is known that the identification performance of a multi-aircraft formation (MAF of narrowband radar mainly depends on the time on target (TOT. To realize the identification task in one rotated scan with limited TOT, the paper proposes a novel identification-while-scanning (IWS method based on sparse recovery to maintain high rotating speed and super-resolution for MAF identification, simultaneously. First, a multiple chirp signal model is established for MAF in a single scan, where different aircraft may have different Doppler centers and Doppler rates. Second, based on the sparsity of MAF in the Doppler parameter space, a novel hierarchical basis pursuit (HBP method is proposed to obtain satisfactory sparse recovery performance as well as high computational efficiency. Furthermore, the parameter estimation performance of the proposed IWS identification method is analyzed with respect to recovery condition, signal-to-noise ratio and TOT. It is shown that an MAF can be effectively identified via HBP with a TOT of only about one hundred microseconds for IWS applications. Finally, some numerical experiment results are provided to demonstrate the effectiveness of the proposed method based on both simulated and real measured data.

  10. 基于FPGA的雷达回波数据记录仪%Radar Echo Data Recorder Based on FPGA

    Institute of Scientific and Technical Information of China (English)

    任敏; 张艳兵; 祖静

    2015-01-01

    针对雷达回波数据具有信息量大、传输速度快等特点,提出了一种基于FPGA的雷达回波数据记录仪。数据记录仪采用FPGA作为中央控制单元,控制各个模块完成雷达回波数据的实时接收,然后将数据按照流水线方式存入Flash存储阵列中。时序仿真和试验测试表明:该系统能够完成大量高速雷达回波数据的记录工作,保证了数据记录的实时性与可靠性。%For radar echo data has the characteristics of large amount of information and fast transmission speed, a radar echo data recorder based on FPGA is designed in this paper. FPGA is used as the central control unit to control various modules completing real-time receiving of the radar echo data. Then the data is recorded in the Flash storage arrays with the pipelined manner. Timing simulation and test show that the system can accomplish the record of a large number of high speed radar echo data, which ensures the real-time and reliability of data record.

  11. Compressive Sensing for MIMO Radar

    CERN Document Server

    Yu, Yao; Poor, H Vincent

    2009-01-01

    Multiple-input multiple-output (MIMO) radar systems have been shown to achieve superior resolution as compared to traditional radar systems with the same number of transmit and receive antennas. This paper considers a distributed MIMO radar scenario, in which each transmit element is a node in a wireless network, and investigates the use of compressive sampling for direction-of-arrival (DOA) estimation. According to the theory of compressive sampling, a signal that is sparse in some domain can be recovered based on far fewer samples than required by the Nyquist sampling theorem. The DOA of targets form a sparse vector in the angle space, and therefore, compressive sampling can be applied for DOA estimation. The proposed approach achieves the superior resolution of MIMO radar with far fewer samples than other approaches. This is particularly useful in a distributed scenario, in which the results at each receive node need to be transmitted to a fusion center for further processing.

  12. Sense and avoid radar for micro/nano robots

    Science.gov (United States)

    Molchanov, Pavlo A.; Asmolova, Olha

    2014-10-01

    Revolutionary new fly eye radar sensor technologies based on an array of directional antennas is eliminating the need for a mechanical scanning antenna or complicated phase processor. Proposed sense and avoid radar based on fly eye radar technology can be very small, provides continuous surveillance of entire sky (360 degree by azimuth and elevation) and can be applied for separate or swarm of micro/nano UAS or UGS. Monopulse technology increases bearing accuracy several folds and radar can be multi-functional, multi-frequency. Fly eye micro-radars are inexpensive, can be expendable. Prototype of sense and avoid radar with two directional antennas has been designed and bench tested.

  13. Island based radar and microwave radiometer measurements of stratus cloud parameters during the Atlantic Stratocumulus Transition Experiment (ASTEX)

    Energy Technology Data Exchange (ETDEWEB)

    Frisch, A.S. [Colorado State Univ., Fort Collins, CO (United States); Fairall, C.W.; Snider, J.B. [NOAA Environmental Technology Lab., Boulder, CO (United States); Lenshow, D.H.; Mayer, S.D. [National Center for Atmospheric Research, Boulder, CO (United States)

    1996-04-01

    During the Atlantic Stratocumulus Transition Experiment (ASTEX) in June 1992, simultaneous measurements were made with a vertically pointing cloud sensing radar and a microwave radiometer. The radar measurements are used to estimate stratus cloud drizzle and turbulence parameters. In addition, with the microwave radiometer measurements of reflectivity, we estimated the profiles of cloud liquid water and effective radius. We used radar data for computation of vertical profiles of various drizzle parameters such as droplet concentration, modal radius, and spread. A sample of these results is shown in Figure 1. In addition, in non-drizzle clouds, with the radar and radiometer we can estimate the verticle profiles of stratus cloud parameters such as liquid water concentration and effective radius. This is accomplished by assuming a droplet distribution with droplet number concentration and width constant with height.

  14. A radar-based regional extreme rainfall analysis to derive the thresholds for a novel automatic alert system in Switzerland

    Science.gov (United States)

    Panziera, Luca; Gabella, Marco; Zanini, Stefano; Hering, Alessandro; Germann, Urs; Berne, Alexis

    2016-06-01

    This paper presents a regional extreme rainfall analysis based on 10 years of radar data for the 159 regions adopted for official natural hazard warnings in Switzerland. Moreover, a nowcasting tool aimed at issuing heavy precipitation regional alerts is introduced. The two topics are closely related, since the extreme rainfall analysis provides the thresholds used by the nowcasting system for the alerts. Warm and cold seasons' monthly maxima of several statistical quantities describing regional rainfall are fitted to a generalized extreme value distribution in order to derive the precipitation amounts corresponding to sub-annual return periods for durations of 1, 3, 6, 12, 24 and 48 h. It is shown that regional return levels exhibit a large spatial variability in Switzerland, and that their spatial distribution strongly depends on the duration of the aggregation period: for accumulations of 3 h and shorter, the largest return levels are found over the northerly alpine slopes, whereas for longer durations the southern Alps exhibit the largest values. The inner alpine chain shows the lowest values, in agreement with previous rainfall climatologies. The nowcasting system presented here is aimed to issue heavy rainfall alerts for a large variety of end users, who are interested in different precipitation characteristics and regions, such as, for example, small urban areas, remote alpine catchments or administrative districts. The alerts are issued not only if the rainfall measured in the immediate past or forecast in the near future exceeds some predefined thresholds but also as soon as the sum of past and forecast precipitation is larger than threshold values. This precipitation total, in fact, has primary importance in applications for which antecedent rainfall is as important as predicted one, such as urban floods early warning systems. The rainfall fields, the statistical quantity representing regional rainfall and the frequency of alerts issued in case of

  15. A novel signal processing approach for LEO space debris based on a fence-type space surveillance radar system

    Science.gov (United States)

    Huang, Jian; Hu, Weidong; Ghogho, Mounir; Xin, Qin; Du, Xiaoyong; Guo, Weiwei

    2012-12-01

    The increase in space debris can seriously threaten regular activities in the Low Earth Orbit (LEO) environment. Therefore, it is necessary to develop robust, efficient and reliable techniques to understand the potential motions of the LEO debris. In this paper, we propose a novel signal processing approach to detect and estimate the motions of LEO space debris that is based on a fence-type space surveillance radar system. Because of the sparse distribution of the orbiting debris through the fence in our observations, we formulate the signal detection and the motion parameter estimation as a sparse signal reconstruction problem with respect to an over-complete dictionary. Moreover, we propose a new scheme to reduce the size of the original over-complete dictionary without the loss of the important information. This new scheme is based on a careful analysis of the relations between the acceleration and the directions of arrival for the corresponding LEO space debris. Our simulation results show that the proposed approach can achieve extremely good performance in terms of the accuracy for detection and estimation. Furthermore, our simulation results demonstrate the robustness of the approach in scenarios with a low Signal-to-Noise Ratio (SNR) and the super-resolution properties. We hope our signal processing approach can stimulate further work on monitoring LEO space debris.

  16. Noncircular Sources-Based Sparse Representation Algorithm for Direction of Arrival Estimation in MIMO Radar with Mutual Coupling

    Directory of Open Access Journals (Sweden)

    Weidong Zhou

    2016-09-01

    Full Text Available In this paper, a reweighted sparse representation algorithm based on noncircular sources is proposed, and the problem of the direction of arrival (DOA estimation for multiple-input multiple-output (MIMO radar with mutual coupling is addressed. Making full use of the special structure of banded symmetric Toeplitz mutual coupling matrices (MCM, the proposed algorithm firstly eliminates the effect of mutual coupling by linear transformation. Then, a reduced dimensional transformation is exploited to reduce the computational complexity of the proposed algorithm. Furthermore, by utilizing the noncircular feature of signals, the new extended received data matrix is formulated to enlarge the array aperture. Finally, based on the new received data, a reweighted matrix is constructed, and the proposed method further designs the joint reweighted sparse representation scheme to achieve the DOA estimation by solving the l 1 -norm constraint minimization problem. The proposed method enlarges the array aperture due to the application of signal noncircularity, and in the presence of mutual coupling, the proposed algorithm provides higher resolution and better angle estimation performance than ESPRIT-like, l 1 -SVD and l 1 -SRDML (sparse representation deterministic maximum likelihood algorithms. Numerical experiment results verify the effectiveness and advantages of the proposed method.

  17. Forest height estimation from mountain forest areas using general model-based decomposition for polarimetric interferometric synthetic aperture radar images

    Science.gov (United States)

    Minh, Nghia Pham; Zou, Bin; Cai, Hongjun; Wang, Chengyi

    2014-01-01

    The estimation of forest parameters over mountain forest areas using polarimetric interferometric synthetic aperture radar (PolInSAR) images is one of the greatest interests in remote sensing applications. For mountain forest areas, scattering mechanisms are strongly affected by the ground topography variations. Most of the previous studies in modeling microwave backscattering signatures of forest area have been carried out over relatively flat areas. Therefore, a new algorithm for the forest height estimation from mountain forest areas using the general model-based decomposition (GMBD) for PolInSAR image is proposed. This algorithm enables the retrieval of not only the forest parameters, but also the magnitude associated with each mechanism. In addition, general double- and single-bounce scattering models are proposed to fit for the cross-polarization and off-diagonal term by separating their independent orientation angle, which remains unachieved in the previous model-based decompositions. The efficiency of the proposed approach is demonstrated with simulated data from PolSARProSim software and ALOS-PALSAR spaceborne PolInSAR datasets over the Kalimantan areas, Indonesia. Experimental results indicate that forest height could be effectively estimated by GMBD.

  18. Design of Radar Echoes Pre-processing Module Based on COM Express%基于COM Express的回波预处理模块设计

    Institute of Scientific and Technical Information of China (English)

    潘奇; 倪卫芳; 张宏超

    2012-01-01

    A radar echoes pre-processing module based on COM Express was designed to met with the rebuild need of data processing platform which is used in shipbome radar.The echoes data receiving bottle-neck of radar system is solved by moving the radar echoes pre-processing function to the interface board,which adjusted the implementation of data processing platform and its software.The paper analyses the rebuild need of data processing platform,described the design plan of the module,the hardware design,the signal flow of echoes data as well as the driver of PEX8311 chip in Vxworks operating system.The module highly improved the processing ability of radar echoes data,witch can receive and process the radar echoes data correctly even in extremely hard station,so it met the need with the rebuild need of radar data processing platform.%针对舰载雷达数据处理平台的改造需求,设计了一种基于COM Express的回波预处理模块.通过调整雷达数据处理平台及软件的实现方式,将回波预处理前移,使用最小的改动量解决了雷达系统的回波数据接收瓶颈问题.分析了数据处理平台的改造需求,介绍了模块的设计方案、模块的硬件设计、回波预处理的数据传输流程以及PEX8311桥片在Vxworks下的驱动设计.工程实践表明,该模块大大提高了雷达的点迹处理能力,在极限情况下能正确接收并处理雷达回波数据,满足了雷达改造需求.

  19. Validation of NASA-TRMM MPA Precipitation Estimates During Tropical Storms Using Gauge and Radar-Based Estimates

    Science.gov (United States)

    Henschke, A. E.; Habib, E.

    2008-05-01

    The purpose of this study is the validation of the 3B42 and 3B42-RT rainfall products from NASA's Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) during major tropical rainfall events throughout the state of Louisiana. The 3B42-RT product, a near real time dataset, and the 3B42 product, a gauge calibrated dataset, are available at .25° x .25°, 3-hourly resolution, covering the globe from 50°N latitude to 50°S latitude. In order to investigate the validity of the TMPA data, radar-based and rain gauge datasets were used as reference. The radar-based dataset, a product of the NWS Stage IV multi- sensor precipitation estimation (MPE) algorithm, is available at 1-hourly intervals on a 4km x 4km spatial scale. The rain gauge dataset was obtained on an hourly scale from a national gauge network maintained by the National Climatic Data Center (NCDC). During the study, six tropical storm periods between 2002 and 2005, ranging in length from three to five days, were examined (Hurricane Lili, October 2002; Tropical Storm Bill, June 2003; Hurricane Ivan, September 2004; Tropical Storm Matthew, October 2004; Hurricane Katrina, August 2005; and Hurricane Rita, September 2005). During the analyzed storms, the radar and rain gauge data were averaged spatially and temporally to match the resolution of the TMPA pixels. The number of pixels studied during each storm varied from three to six pixels, with a minimum requirement of three gauges per 3B42 pixel, depending on the gauge density at the landfall location of the storm. Evaluation of the 3B42/3B42-RT error was performed on a storm by storm basis as well as an overall accumulation of data from all six storms using error metrics including the relative mean difference, relative standard deviation, correlation coefficient, and probability of detection. Significant variability in the performance metrics were observed between the different analyzed storms. Enhanced performance in terms of

  20. Passive Microwave Soil Moisture Retrieval through Combined Radar/Radiometer Ground Based Simulator with Special Reference to Dielectric Schemes

    Science.gov (United States)

    Srivastava, Prashant K., ,, Dr.; O'Neill, Peggy, ,, Dr.

    2014-05-01

    Soil moisture is an important element for weather and climate prediction, hydrological sciences, and applications. Hence, measurements of this hydrologic variable are required to improve our understanding of hydrological processes, ecosystem functions, and the linkages between the Earth's water, energy, and carbon cycles (Srivastava et al. 2013). The retrieval of soil moisture depends not only on parameterizations in the retrieval algorithm but also on the soil dielectric mixing models used (Behari 2005). Although a number of soil dielectric mixing models have been developed, testing these models for soil moisture retrieval has still not been fully explored, especially with SMAP-like simulators. The main objective of this work focuses on testing different dielectric models for soil moisture retrieval using the Combined Radar/Radiometer (ComRAD) ground-based L-band simulator developed jointly by NASA/GSFC and George Washington University (O'Neill et al., 2006). The ComRAD system was deployed during a field experiment in 2012 in order to provide long active/passive measurements of two crops under controlled conditions during an entire growing season. L-band passive data were acquired at a look angle of 40 degree from nadir at both horizontal & vertical polarization. Currently, there are many dielectric models available for soil moisture retrieval; however, four dielectric models (Mironov, Dobson, Wang & Schmugge and Hallikainen) were tested here and found to be promising for soil moisture retrieval (some with higher performances). All the above-mentioned dielectric models were integrated with Single Channel Algorithms using H (SCA-H) and V (SCA-V) polarizations for the soil moisture retrievals. All the ground-based observations were collected from test site-United States Department of Agriculture (USDA) OPE3, located a few miles away from NASA GSFC. Ground truth data were collected using a theta probe and in situ sensors which were then used for validation. Analysis

  1. Applicability of Doppler weather radar based rainfall data for runoff estimation in Indian watersheds – A case study of Chennai basin

    Indian Academy of Sciences (India)

    V S Josephine; B V Mudgal; S B Thampi

    2014-08-01

    Traditionally, India has been vulnerable to various hazards such as floods, droughts and cyclones. About 8% of the total Indian landmass is prone to cyclones. A number of Doppler weather radars are installed in India and their products are utilized for weather predictions and detection of cyclones approaching the Indian coast. Radar-based hydrological studies in various countries have proven that computation of runoff using radar rainfall data could outperform rain gauge network measurements. There are no reported studies on their utilization for hydrological modelling and/or flood-related studies in Indian river basins. A comparison study between Doppler weather radar (DWR) derived rainfall data and the conventional rain gauge data was carried out with hourly inputs at one of the watersheds of Chennai basin, Tamil Nadu, India using HEC-HMS model. The model calibration and validation were performed by comparing the simulated outflow with the observed daily outflow data. The calibrated model was used to predict runoff from two post-monsoon cyclonic storm events with hourly inputs. It was noticed that the discrepancy in the runoff volume was small, but the difference in the peak flow was substantial. Additionally, there was a variation at the time to peak flow using daily and hourly inputs. The results show that the use of radar data may be optional for runoff volume estimation for the watersheds with sufficient rain gauge density, but highly desirable for peak flow and time to peak estimation. Therefore, the DWR derived rainfall data is a promising input for runoff estimation, especially in urban flood modelling.

  2. Radar clutter classification

    Science.gov (United States)

    Stehwien, Wolfgang

    1989-11-01

    The problem of classifying radar clutter as found on air traffic control radar systems is studied. An algorithm based on Bayes decision theory and the parametric maximum a posteriori probability classifier is developed to perform this classification automatically. This classifier employs a quadratic discriminant function and is optimum for feature vectors that are distributed according to the multivariate normal density. Separable clutter classes are most likely to arise from the analysis of the Doppler spectrum. Specifically, a feature set based on the complex reflection coefficients of the lattice prediction error filter is proposed. The classifier is tested using data recorded from L-band air traffic control radars. The Doppler spectra of these data are examined; the properties of the feature set computed using these data are studied in terms of both the marginal and multivariate statistics. Several strategies involving different numbers of features, class assignments, and data set pretesting according to Doppler frequency and signal to noise ratio were evaluated before settling on a workable algorithm. Final results are presented in terms of experimental misclassification rates and simulated and classified plane position indicator displays.

  3. Ground-based Radar Detection of Near-Earth Asteroids%近地小行星地基雷达探测研究现状

    Institute of Scientific and Technical Information of China (English)

    张翔; 季江徽

    2014-01-01

    Ground-based radar detection may act as a powerful means to determine the shape and physical properties of the asteroids in our Solar system. By measuring time delay and doppler frequency of the received echoes, radar systems provide information in ranging and radial velocity of the asteroids. Over the past few decades, more than 500 asteroids (mostly near-Earth ob jects) were detected using radar observations. There are two categories of radar detection: (1) The continuous wave detection, which is adopted to determine the roughness of an asteroid’s surface. (2) The delay-Doppler de-tection,which is likely to produce its three-dimensional model, and to define the rotational state. In the delay-Doppler detection, target asteroids are resolved in line-of-sight distance and line-of-sight velocity, providing two-dimensional images with spatial resolution as fine as meter-scale. Besides radar detection, several other techniques would also provide the shape model of the asteroids, among which the lightcurve inverse method is the most popular one to do that. In comparison with other methods, radar observation may have an advantage on spacial resolution. The lightcurves cannot reveal elaborate information on small features, and the intermediate-scale features of the inversed model are only suggestive. By contrast, radar detection produces resolved images. In this review, we present the radar observation technique and the method for recon-structing three-dimensional models of asteroids from radar measurements. In addition, we also provide several examples of asteroid models by radar detection, and then compare them with other observations for the shape reconstruction for the asteroids.%地基雷达探测是研究太阳系中小行星的重要方法。雷达探测主要有两种方式:(1)连续波探测,可得到小行星表面的粗糙度等参数;(2)延迟多普勒探测,用于反演小行星的三维形状模型并确定自转轴状态。与其他探测方法

  4. Capacidade combinatoria de capim elefante com base em caracteres morfoagronomicos

    Directory of Open Access Journals (Sweden)

    Vanessa Quitete Ribeiro da Silva

    2014-01-01

    Full Text Available Devido ao grande potencial de produção de biomassa do capim elefante, objetivou-se neste trabalho avaliar genitores para geração de híbridos superiores. Para tanto, foram estimados os efeitos da capacidade geral de combinação (CGC dos genitores e da capacidade específica de combinação (CEC de híbridos de capim elefante por meio de análise dialélica adaptada a dialelos parciais. Foram avaliados 16 híbridos e oito genitores utilizando delineamento em blocos casualizados com três repetições. Verificou-se a presença de variabilidade genética entre os híbridos e genitores, com predominância do efeito gênico de dominância para a maioria das características. De forma geral, os melhores resultados na CGC são os genitores Taiwan A-144, Vruckwona Africana e Taiwan A-146. Os melhores cruzamentos com base na CEC são Taiwan A-144 x Taiwan A-146 e Pusa Napier nº2 x Mercker Santa Rita.

  5. Volcanic Ash Cloud Observation using Ground-based Ka-band Radar and Near-Infrared Lidar Ceilometer during the Eyjafjallajökull eruption

    Directory of Open Access Journals (Sweden)

    Frank S. Marzano

    2015-03-01

    Full Text Available Active remote sensing techniques can probe volcanic ash plumes, but their sensitivity at a given distance depends upon the sensor transmitted power, wavelength and polarization capability. Building on a previous numerical study at centimeter wavelength, this work aims at i simulating the distal ash particles polarimetric response of millimeter-wave radar and multi-wavelength optical lidar; ii developing and applying a model-based statistical retrieval scheme using a multi-sensor approach. The microphysical electromagnetic forward model of volcanic ash particle distribution, previously set up at microwaves, is extended to include non-spherical particle shapes, vesicular composition, silicate content and orientation phenomena for both millimeter and optical bands. Monte Carlo generation of radar and lidar signatures are driven by random variability of volcanic particle main parameters, using constraints from available data and experimental evidences. The considered case study is related to the ground-based observation of the Eyjafjallajökull (Iceland volcanic ash plume on May 15, 2010, carried out by the Atmospheric Research Station at Mace Head (Ireland with a 35-GHz Ka-band Doppler cloud radar and a 1064-nm ceilometer lidar. The detection and estimation of ash layer presence and composition is carried out using a Bayesian approach, which is trained by the Monte Carlo model-based dataset. Retrieval results are corroborated exploiting auxiliary data such as those from a ground-based microwave radiometer also positioned at Mace Head.

  6. A design on key technology of radar signal source based on FPGA%基于FPGA的雷达信号源关键技术设计

    Institute of Scientific and Technical Information of China (English)

    金牡丹

    2011-01-01

    提出了一种基于FPGA的复杂雷达信号模拟源的设计方法。基于FPGA来实现雷达信号模拟源的复杂信号产生,使系统集成度高、可靠性好。在系统中采用了SCM(单片机),使系统可配合PC机工作,也可独立工作,是本信号源的关键技术。%A design on the complex radar signal simulation source based on the FPGA is presented.The generation of the complex signals of radar signal simulation source with the high integration and reliability of the system is implemented based on the FPGA.The Sing

  7. A Methodology for Assessing Technology Trade-Offs of Space-Based Radar Concepts.

    Science.gov (United States)

    1985-12-01

    objective reality and intuition as reflected in a decision maker’s judgments. Especially in the case of future space sys- teams , decisions must be based...data base based on their perceptions of the technology issues from their own field of expertise. Networking can provide a means for intradisciplinary

  8. DC-17-GHz CMOS single-pole-eight-throw switching matrix for radar-based image detection

    Science.gov (United States)

    Azhari, Afreen; Sugitani, Takumi; Xiao, Xia; Kikkawa, Takamaro

    2016-12-01

    A new 65-nm-thick single-pole-eight-throw CMOS integrated switching matrix has been developed to control a multiple-input-multiple-output radar-based imaging system, and it can replace the conventional mechanical switching system. The switch has a minimum input and output matching bandwidth of 0-17 GHz with an average insertion loss of 3 to 10 dB from 2 to 17 GHz. A wide bandwidth was designed for the transmission of the 8-GHz-center-frequency, 16-GHz-bandwidth Gaussian monocycle pulse with low distortion. A bandwidth from 0-20 GHz of the switch on the printed circuit board was achieved by flip chip mounting, quarter-wave (λ/4)-length microstrip line impedance matching, and optimization of the board dielectric constant and thickness. With the utilization of two of these switching matrices on the PCB, it became possible to control 16 antennas in a 16-antenna-array breast cancer detection system to detect an aluminum target of 10 × 10 mm2 at a depth of 20 mm.

  9. Prototyping a GNSS-Based Passive Radar for UAVs: An Instrument to Classify the Water Content Feature of Lands

    Directory of Open Access Journals (Sweden)

    Micaela Troglia Gamba

    2015-11-01

    Full Text Available Global Navigation Satellite Systems (GNSS broadcast signals for positioning and navigation, which can be also employed for remote sensing applications. Indeed, the satellites of any GNSS can be seen as synchronized sources of electromagnetic radiation, and specific processing of the signals reflected back from the ground can be used to estimate the geophysical properties of the Earth’s surface. Several experiments have successfully demonstrated GNSS-reflectometry (GNSS-R, whereas new applications are continuously emerging and are presently under development, either from static or dynamic platforms. GNSS-R can be implemented at a low cost, primarily if small devices are mounted on-board unmanned aerial vehicles (UAVs, which today can be equipped with several types of sensors for environmental monitoring. So far, many instruments for GNSS-R have followed the GNSS bistatic radar architecture and consisted of custom GNSS receivers, often requiring a personal computer and bulky systems to store large amounts of data. This paper presents the development of a GNSS-based sensor for UAVs and small manned aircraft, used to classify lands according to their soil water content. The paper provides details on the design of the major hardware and software components, as well as the description of the results obtained through field tests.

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

    Science.gov (United States)

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

    2011-05-01

    A ground-penetrating radar (GPR) survey of a 32 km mixed urban and rural study route is undertaken to assess the usefulness of GPR as a tool for parameterizing road construction in a route-based road weather forecast model. It is shown that GPR can easily identify even the smallest of bridges along the route, which previous thermal mapping surveys have identified as thermal singularities with implications for winter road maintenance. Using individual GPR traces measured at each forecast point along the route, an inflexion point detection algorithm attempts to identify the depth of the uppermost subsurface layers at each forecast point for use in a road weather model instead of existing ordinal road-type classifications. This approach has the potential to allow high resolution modelling of road construction and bridge decks on a scale previously not possible within a road weather model, but initial results reveal that significant future research will be required to unlock the full potential that this technology can bring to the road weather industry.

  11. Analysis of Target Classification Based on Radar Detection%雷达目标的分类识别技术

    Institute of Scientific and Technical Information of China (English)

    刘大伟

    2013-01-01

    文章总结了雷达探测的目标类型,给出了各种类型目标的基本特性,确定了雷达目标识别的需求,回顾了用于目标识别的一些主要技术及其实现原理,同时比较了各种技术的优劣。最后文章给出了提高雷达目标识别性能的建议:识别参量优化技术、高分辨技术以及引入现代信号处理、模式识别及人工智能等技术。%The paper summarizes the targets types and classifying need. General feature are given as well. Several populous classifi-ers are listed in the paper. The paper analyzes their performance respectively. According to the description given, in the end, the paper put forward pieces of advice. They are: optimization of parameter vector based on in-hand radar, ultra-high resolution techniques and introduction of modern signal procession, pattern recognition and artificial intelligence.

  12. Full-polarization radar remote sensing and data mining for tropical crops mapping: a successful SVM-based classification model

    Science.gov (United States)

    Denize, J.; Corgne, S.; Todoroff, P.; LE Mezo, L.

    2015-12-01

    In Reunion, a tropical island of 2,512 km², 700 km east of Madagascar in the Indian Ocean, constrained by a rugged relief, agricultural sectors are competing in highly fragmented agricultural land constituted by heterogeneous farming systems from corporate to small-scale farming. Policymakers, planners and institutions are in dire need of reliable and updated land use references. Actually conventional land use mapping methods are inefficient under the tropic with frequent cloud cover and loosely synchronous vegetative cycles of the crops due to a constant temperature. This study aims to provide an appropriate method for the identification and mapping of tropical crops by remote sensing. For this purpose, we assess the potential of polarimetric SAR imagery associated with associated with machine learning algorithms. The method has been developed and tested on a study area of 25*25 km thanks to 6 RADARSAT-2 images in 2014 in full-polarization. A set of radar indicators (backscatter coefficient, bands ratios, indices, polarimetric decompositions (Freeman-Durden, Van zyl, Yamaguchi, Cloude and Pottier, Krogager), texture, etc.) was calculated from the coherency matrix. A random forest procedure allowed the selection of the most important variables on each images to reduce the dimension of the dataset and the processing time. Support Vector Machines (SVM), allowed the classification of these indicators based on a learning database created from field observations in 2013. The method shows an overall accuracy of 88% with a Kappa index of 0.82 for the identification of four major crops.

  13. Prototyping a GNSS-Based Passive Radar for UAVs: An Instrument to Classify the Water Content Feature of Lands.

    Science.gov (United States)

    Gamba, Micaela Troglia; Marucco, Gianluca; Pini, Marco; Ugazio, Sabrina; Falletti, Emanuela; Lo Presti, Letizia

    2015-11-10

    Global Navigation Satellite Systems (GNSS) broadcast signals for positioning and navigation, which can be also employed for remote sensing applications. Indeed, the satellites of any GNSS can be seen as synchronized sources of electromagnetic radiation, and specific processing of the signals reflected back from the ground can be used to estimate the geophysical properties of the Earth's surface. Several experiments have successfully demonstrated GNSS-reflectometry (GNSS-R), whereas new applications are continuously emerging and are presently under development, either from static or dynamic platforms. GNSS-R can be implemented at a low cost, primarily if small devices are mounted on-board unmanned aerial vehicles (UAVs), which today can be equipped with several types of sensors for environmental monitoring. So far, many instruments for GNSS-R have followed the GNSS bistatic radar architecture and consisted of custom GNSS receivers, often requiring a personal computer and bulky systems to store large amounts of data. This paper presents the development of a GNSS-based sensor for UAVs and small manned aircraft, used to classify lands according to their soil water content. The paper provides details on the design of the major hardware and software components, as well as the description of the results obtained through field tests.

  14. Automotive Radar Sensors in Silicon Technologies

    CERN Document Server

    Jain, Vipul

    2013-01-01

    This book presents architectures and design techniques for mm-wave automotive radar transceivers. Several fully-integrated transceivers and receivers operating at 22-29 GHz and 77-81 GHz are demonstrated in both CMOS and SiGe BiCMOS technologies. Excellent performance is achieved indicating the suitability of silicon technologies for automotive radar sensors.  This book bridges an existing gap between information available on dependable system/architecture design and circuit design.  It provides the background of the field and detailed description of recent research and development of silicon-based radar sensors.  System-level requirements and circuit topologies for radar transceivers are described in detail. Holistic approaches towards designing radar sensors are validated with several examples of highly-integrated radar ICs in silicon technologies. Circuit techniques to design millimeter-wave circuits in silicon technologies are discussed in depth.  Describes concepts and fundamentals of automotive rada...

  15. Radar activities of the DFVLR Institute for Radio Frequency Technology

    Science.gov (United States)

    Keydel, W.

    1983-01-01

    Aerospace research and the respective applications microwave tasks with respect to remote sensing, position finding and communication are discussed. The radar activities are directed at point targets, area targets and volume targets; they center around signature research for earth and ocean remote sensing, target recognition, reconnaissance and camouflage and imaging and area observation radar techniques (SAR and SLAR). The radar activities cover a frequency range from 1 GHz up to 94 GHz. The radar program is oriented to four possible application levels: ground, air, shuttle orbits and satellite orbits. Ground based studies and measurements, airborne scatterometers and imaging radars, a space shuttle radar, the MRSE, and follow on experiments are considered.

  16. Divergência genética em acessos de quiabeiro com base em marcadores morfológicos

    Directory of Open Access Journals (Sweden)

    Martinello Gilmar Efrem

    2002-01-01

    Full Text Available Vinte e sete caracteres morfoagronômicos, 13 quantitativos e 14 qualitativos, foram utilizados para a avaliação da diversidade genética em 39 acessos do gênero Abelmoschus, por meio das análises de agrupamento hierárquico do vizinho mais próximo e de componentes principais, utilizando-se a distância Euclidiana média padronizada como medida de dissimilaridade. As plantas foram cultivadas em condições de campo na Universidade Estadual do Norte Fluminense, em Campos dos Goytacazes, utilizando-se o delineamento experimental em blocos ao acaso com quatro repetições. A formação dos grupos de acessos, com base no método hierárquico do vizinho mais próximo, revelou resultados semelhantes aos obtidos pela análise em componentes principais, já que ambos os métodos reuniram os acessos de A. esculentus e A. caillei. O método hierárquico agrupou os genótipos de forma idêntica tanto para os 27 descritores quantitativos e qualitativos quanto para os 13 descritores quantitativos separadamente, demonstrando que os descritores qualitativos tiveram pouca influência na discriminação genotípica. Por outro lado, os descritores qualitativos foram capazes de classificar corretamente as espécies, porém mascararam a variabilidade genética no germoplasma, não possibilitando um rastreamento mais abrangente dos genomas. Os descritores que menos contribuíram para a discriminação dos acessos foram, largura do epicálice, peso de 100 sementes, número de segmentos do estigma, altura da planta, comprimento da folha, largura da folha, nó do primeiro florescimento e comprimento do fruto.

  17. Radar Investigations of Asteroids

    Science.gov (United States)

    Ostro, S.

    2004-05-01

    Radar investigations have provided otherwise unavailable information about the physical and dynamical properties of about 230 asteroids. Measurements of the distribution of echo power in time delay (range) and Doppler frequency (line-of-sight velocity) provide two-dimensional images with spatial resolution as fine as a decameter. Sequences of delay-Doppler images can be used to produce geologically detailed three-dimensional models, to define the rotation state precisely, to constrain the internal density distribution, and to estimate the trajectory of the object's center of mass. Radar wavelengths (4 to 13 cm) and the observer's control of transmitted and received polarizations make the observations sensitive to near-surface bulk density and macroscopic structure. Since delay-Doppler measurements are orthogonal to optical angle measurements and typically have much finer fractional precision, they are powerful for refining orbits and prediction ephemerides. Such astrometric measurements can add decades or centuries to the interval over which an asteroid's close Earth approaches can accurately be predicted and can significantly refine collision probability estimates based on optical astrometry alone. In the highly unlikely case that a small body is on course for an Earth collision in this century, radar reconnaissance would almost immediately distinguish between an impact trajectory and a near miss and would dramatically reduce the difficulty and cost of any effort to prevent the collision. The sizes and rotation periods of radar-detected asteroids span more than four orders of magnitude. The observations have revealed both stony and metallic objects, elongated and nonconvex shapes as well as nearly featureless spheroids, small-scale morphology ranging from smoother than the lunar regolith to rougher than the rockiest terrain on Mars, craters and diverse linear structures, non-principal-axis spin states, contact binaries, and binary systems.

  18. Radar interferometry based settlement monitoring in tunnelling: visualisation and accuracy analyses

    OpenAIRE

    Schindler, Steffen; Hegemann, Felix; Koch, Christian; König, Markus; Mark, Peter

    2016-01-01

    Background The accurate, efficient and economical monitoring of settlements caused by tunnel boring machines, especially in regions of particular interest such as critical inner city areas, has become an important aspect of the tunnelling operation. Besides conventional terrestrial based methods to capture settlements, satellite based techniques that can accurately determine displacements remotely, are increasingly being used to augment standard terrestrial measurements. However, not much...

  19. Analysis of Terminal Velocity and VHF Backscatter of Precipitation Particles Using Chung-Li VHF Radar Combined with Ground-Based Disdrometer

    Directory of Open Access Journals (Sweden)

    Ching-Lun Su and Yen-Hsyang Chu

    2007-01-01

    Full Text Available The backscatter from precipitation particles observed by the vertically pointed antenna beam of the Chung-Li VHF radar and the drop size distributions measured by a ground-based disdrometer co-located at the radar site are analyzed and studied in this article. We find that the disdrometermeasured drop size distribution can be well approximated to a Gamma distribution. On the basis of this property and a power law approximation to the fallspeed-diameter relation VD = ADB, we derive the theoretical relation between terminal velocity VD and range-corrected VHF backscatter P of the precipitation particles. We find that the VD - P relation follows a power law in the form of VD = _ where _ _ both the functions of the precipitation parameters. Chu et al. (1999 first found that the relation between _ _ be empirically approximated to an exponential form of _ _ where _ a function of B and _ a factor associated with precipitation. In this article, under the assumptions of the Gamma distribution of the drop size distribution and the power-law relation between VD and D, we theoretically show that the analytical relation between _ _ follows an exponential form of _ _ where _ a function of the drop size distribution. The experimental results obtained by the Chung-Li VHF radar combined with the ground-based disdrometer measurements validate the exponential approximation to the _ _ The uses of the _ _ for the investigations of the rainfall rate and properties of drop size distribution are presented and discussed.

  20. 基于几何法的雷达与ESM航迹关联算法%Radar-ESM Track Correlation Based on Geometric Method

    Institute of Scientific and Technical Information of China (English)

    陈中华; 王国宏; 刘德浩; 谭顺成

    2012-01-01

    为解决雷达与ESM航迹关联门限的不确定性,提出了基于几何法的雷达与ESM航迹关联算法.该算法根据雷达与ESM的几何位置建立航迹粗关联函数,并利用航迹的历史信息建立航迹关联代价矩阵,通过代价最小实现航迹关联.仿真结果表明,该算法具有很好的关联性能.%In order to deal with the uncertainty thresholds of Radar-ESM ( Electronic Support Measures) correlation, an Radar-ESM correlation mode based on geometric method was proposed. Firstly, a coarse correlation function was built up based on the geometric position of radar and ESM. Then,a cost correlation matrix was set up by accumulating the historical information of the coarse correlation. Thus the track correlation was realized by finding the minimum cost of cost matrix. Finally, the correlation method proposed was verified by Monte Carlo simulation.

  1. Mapping plasma structures in the high-latitude ionosphere using beacon satellite, incoherent scatter radar and ground-based magnetometer observations

    Directory of Open Access Journals (Sweden)

    T. Neubert

    2002-06-01

    Full Text Available In the autumn of the year 2000, four radio receivers capable of tracking various beacon satellites were set up along the southwestern coast of Greenland. They are used to reconstruct images of the ionospheric plasma density distribution via the tomographic method. In order to test and validate tomographic imaging under the highly variable conditions often prevailing in the high-latitude ionosphere, a time interval was selected when the Sondrestrom incoherent scatter radar conducted measurements of the ionospheric plasma density while the radio receivers tracked a number of beacon satellites. A comparison between two-dimensional images of the plasma density distribution obtained from the radar and the satellite receivers revealed generally good agreement between radar measurements and tomographic images. Observed discrepancies can be attributed to F region plasma patches moving through the field of view with a speed of several hundred meters per second, thereby smearing out the tomographic image. A notable mismatch occurred around local magnetic midnight when a magnetospheric substorm breakup occurred in the vicinity of southwest Greenland (identified from ground-based magnetometer observations. The breakup was associated with a sudden intensification of the westward auroral electrojet which was centered at about 69 and extended up to some 73 corrected geomagnetic latitude. Ground-based magnetometer data may thus have the potential of indicating when the tomographic method is at risk and may fail. We finally outline the application of tomographic imaging, when combined with magnetic field data, to estimate ionospheric Joule heating rates.

  2. Validation of Satellite-Based Objective Overshooting Cloud-Top Detection Methods Using CloudSat Cloud Profiling Radar Observations

    Science.gov (United States)

    Bedka, Kristopher M.; Dworak, Richard; Brunner, Jason; Feltz, Wayne

    2012-01-01

    Two satellite infrared-based overshooting convective cloud-top (OT) detection methods have recently been described in the literature: 1) the 11-mm infrared window channel texture (IRW texture) method, which uses IRW channel brightness temperature (BT) spatial gradients and thresholds, and 2) the water vapor minus IRW BT difference (WV-IRW BTD). While both methods show good performance in published case study examples, it is important to quantitatively validate these methods relative to overshooting top events across the globe. Unfortunately, no overshooting top database currently exists that could be used in such study. This study examines National Aeronautics and Space Administration CloudSat Cloud Profiling Radar data to develop an OT detection validation database that is used to evaluate the IRW-texture and WV-IRW BTD OT detection methods. CloudSat data were manually examined over a 1.5-yr period to identify cases in which the cloud top penetrates above the tropopause height defined by a numerical weather prediction model and the surrounding cirrus anvil cloud top, producing 111 confirmed overshooting top events. When applied to Moderate Resolution Imaging Spectroradiometer (MODIS)-based Geostationary Operational Environmental Satellite-R Series (GOES-R) Advanced Baseline Imager proxy data, the IRW-texture (WV-IRW BTD) method offered a 76% (96%) probability of OT detection (POD) and 16% (81%) false-alarm ratio. Case study examples show that WV-IRW BTD.0 K identifies much of the deep convective cloud top, while the IRW-texture method focuses only on regions with a spatial scale near that of commonly observed OTs. The POD decreases by 20% when IRW-texture is applied to current geostationary imager data, highlighting the importance of imager spatial resolution for observing and detecting OT regions.

  3. Retrieving Microphysical Properties and Air Motion of Cirrus Clouds Based on the Doppler Moments Method Using Cloud Radar

    Institute of Scientific and Technical Information of China (English)

    ZHONG Lingzhi; LIU Liping; DENG Min; ZHOU Xiuji

    2012-01-01

    Radar parameters including radar reflectivity,Doppler velocity,and Doppler spectrum width were obtained from Doppler spectrum moments.The Doppler spectrum moment is the convolution of both the particle spectrum and the mean air vertical motion.Unlike strong precipitation,the motion of particles in cirrus clouds is quite close to the air motion around them.In this study,a method of Doppler moments was developed and used to retrieve cirrus cloud microphysical properties such as the mean air vertical velocity,mass-weighted diameter,effective particle size,and ice content. Ice content values were retrieved using both the Doppler spectrum method and classic Z-IWC (radar reflectivity-ice water content) relationships;however,the former is a more reasonable method.

  4. Adaptive radar resource management

    CERN Document Server

    Moo, Peter

    2015-01-01

    Radar Resource Management (RRM) is vital for optimizing the performance of modern phased array radars, which are the primary sensor for aircraft, ships, and land platforms. Adaptive Radar Resource Management gives an introduction to radar resource management (RRM), presenting a clear overview of different approaches and techniques, making it very suitable for radar practitioners and researchers in industry and universities. Coverage includes: RRM's role in optimizing the performance of modern phased array radars The advantages of adaptivity in implementing RRMThe role that modelling and

  5. Radar and ARPA manual

    CERN Document Server

    Bole, A G

    2013-01-01

    Radar and ARPA Manual focuses on the theoretical and practical aspects of electronic navigation. The manual first discusses basic radar principles, including principles of range and bearing measurements and picture orientation and presentation. The text then looks at the operational principles of radar systems. Function of units; aerial, receiver, and display principles; transmitter principles; and sitting of units on board ships are discussed. The book also describes target detection, Automatic Radar Plotting Aids (ARPA), and operational controls of radar systems, and then discusses radar plo

  6. A grid-based distributed flood forecasting model for use with weather radar data: Part 1. Formulation

    Science.gov (United States)

    Bell, V. A.; Moore, R. J.

    A practical methodology for distributed rainfall-runoff modelling using grid square weather radar data is developed for use in real-time flood forecasting. The model, called the Grid Model, is configured so as to share the same grid as used by the weather radar, thereby exploiting the distributed rainfall estimates to the full. Each grid square in the catchment is conceptualised as a storage which receives water as precipitation and generates water by overflow and drainage. This water is routed across the catchment using isochrone pathways. These are derived from a digital terrain model assuming two fixed velocities of travel for land and river pathways which are regarded as model parameters to be optimised. Translation of water between isochrones is achieved using a discrete kinematic routing procedure, parameterised through a single dimensionless wave speed parameter, which advects the water and incorporates diffusion effects through the discrete space-time formulation. The basic model routes overflow and drainage separately through a parallel system of kinematic routing reaches, characterised by different wave speeds but using the same isochrone-based space discretisation; these represent fast and slow pathways to the basin outlet, respectively. A variant allows the slow pathway to have separate isochrones calculated using Darcy velocities controlled by the hydraulic gradient as estimated by the local gradient of the terrain. Runoff production within a grid square is controlled by its absorption capacity which is parameterised through a simple linkage function to the mean gradient in the square, as calculated from digital terrain data. This allows absorption capacity to be specified differently for every grid square in the catchment through the use of only two regional parameters and a DTM measurement of mean gradient for each square. An extension of this basic idea to consider the distribution of gradient within the square leads analytically to a Pareto

  7. A grid-based distributed flood forecasting model for use with weather radar data: Part 1. Formulation

    Directory of Open Access Journals (Sweden)

    V. A. Bell

    1998-01-01

    Full Text Available A practical methodology for distributed rainfall-runoff modelling using grid square weather radar data is developed for use in real-time flood forecasting. The model, called the Grid Model, is configured so as to share the same grid as used by the weather radar, thereby exploiting the distributed rainfall estimates to the full. Each grid square in the catchment is conceptualised as a storage which receives water as precipitation and generates water by overflow and drainage. This water is routed across the catchment using isochrone pathways. These are derived from a digital terrain model assuming two fixed velocities of travel for land and river pathways which are regarded as model parameters to be optimised. Translation of water between isochrones is achieved using a discrete kinematic routing procedure, parameterised through a single dimensionless wave speed parameter, which advects the water and incorporates diffusion effects through the discrete space-time formulation. The basic model routes overflow and drainage separately through a parallel system of kinematic routing reaches, characterised by different wave speeds but using the same isochrone-based space discretisation; these represent fast and slow pathways to the basin outlet, respectively. A variant allows the slow pathway to have separate isochrones calculated using Darcy velocities controlled by the hydraulic gradient as estimated by the local gradient of the terrain. Runoff production within a grid square is controlled by its absorption capacity which is parameterised through a simple linkage function to the mean gradient in the square, as calculated from digital terrain data. This allows absorption capacity to be specified differently for every grid square in the catchment through the use of only two regional parameters and a DTM measurement of mean gradient for each square. An extension of this basic idea to consider the distribution of gradient within the square leads analytically

  8. Non-contact multi-radar smart probing of body orientation based on micro-Doppler signatures.

    Science.gov (United States)

    Li, Yiran; Pal, Ranadip; Li, Changzhi

    2014-01-01

    Micro-Doppler signatures carry useful information about body movements and have been widely applied to different applications such as human activity recognition and gait analysis. In this paper, micro-Doppler signatures are used to identify body orientation. Four AC-coupled continuous-wave (CW) smart radar sensors were used to form a multiple-radar network to carry out the experiments in this paper. 162 tests were performed in total. The experiment results showed a 100% accuracy in recognizing eight body orientations, i.e., facing north, northeast, east, southeast, south, southwest, west, and northwest.

  9. Development of radar-based system for monitoring of frail home-dwelling persons: A healthcare perspective

    Science.gov (United States)

    Sudmann, Tobba T.; Børsheim, Ingebjørg T.; Øvsthus, Knut; Ciamulski, Tomasz; Miękina, Andrzej; Wagner, Jakub; Mazurek, Paweł; Jacobsen, Frode F.

    2016-11-01

    This interdisciplinary project aims to develop and assess the functional potential of radar technology in the care services. The project mainly has an exploratory character where the technological and functional potential of impulse-radar sensor are tested out in monitoring of elderly and disabled people living in their own home. Designing a non-invasive system for monitoring of movements of frail persons living at home is the main goal, with the intent of assessing health and functional status through monitoring of activities of daily life (ADL) and detecting potentially dangerous situations, not the least related to a long lie following falls.

  10. Gravimetric Radar: Gravity-Based Detection of a Point-Mass Moving in a Static Background

    CERN Document Server

    Tannenbaum, Emmanuel David

    2012-01-01

    This paper discusses a novel approach for detecting moving massive objects based on the time variation that these objects produce in the local gravitational field measured by several detectors. Such an approach may provide a viable method for detecting stealth aircraft, UAVs, cruise, and ballistic missiles. By inverting a set of nonlinear algebraic equations, it is possible to use the time variation in the gravitational fields to compute the mass, position, and velocity of one or more moving objects. The approach is essentially a gravity-based form of triangulation. Based on order-of-magnitude calculations, we estimate that under realistic scenarios, this approach will be feasible if it is possible to design gravimetric devices that are four to five order of magnitude more sensitive than current devices. To achieve such a level of sensitivity, we suggest designing detectors that exploit a quantum-mechanical effect known as gravity-induced quantum interference. Furthermore, even if we have a perfect detector, ...

  11. Incidence angle normalization of radar backscatter data

    Science.gov (United States)

    NASA’s Soil Moisture Passive Active (SMAP) satellite (~2014) will include a radar system that will provide L-band multi-polarization backscatter at a constant incidence angle of 40º. During the pre-launch phase of the project there is a need for observations that will support the radar-based soil mo...

  12. Aspects of Applying Weather Radar-Based Nowcasts of Rainfall for Highways in Denmark

    DEFF Research Database (Denmark)

    Rasmussen, Michael R.; Thorndahl, Søren Liedtke; Quist, M.

    2012-01-01

    This work investigates three different approaches to nowcasting rainfall for highways. The simplest method is based on using the observed precipitation field at the beginning of the trip. The most developed nowcast is based on a COTREC nowcaster, which is dynamically adjusted to online raingauges....... The nowcasts are performed with a lead time of up to 2 h. The average speed on Danish highways varies between 110 and 130 km/h. As a result, the performance of the nowcast is dependent on the direction of the precipitation and the direction and speed of the road users, as well as the type of precipitation...

  13. A Parallel, High-Fidelity Radar Model

    Science.gov (United States)

    Horsley, M.; Fasenfest, B.

    2010-09-01

    Accurate modeling of Space Surveillance sensors is necessary for a variety of applications. Accurate models can be used to perform trade studies on sensor designs, locations, and scheduling. In addition, they can be used to predict system-level performance of the Space Surveillance Network to a collision or satellite break-up event. A high fidelity physics-based radar simulator has been developed for Space Surveillance applications. This simulator is designed in a modular fashion, where each module describes a particular physical process or radar function (radio wave propagation & scattering, waveform generation, noise sources, etc.) involved in simulating the radar and its environment. For each of these modules, multiple versions are available in order to meet the end-users needs and requirements. For instance, the radar simulator supports different atmospheric models in order to facilitate different methods of simulating refraction of the radar beam. The radar model also has the capability to use highly accurate radar cross sections generated by the method of moments, accelerated by the fast multipole method. To accelerate this computationally expensive model, it is parallelized using MPI. As a testing framework for the radar model, it is incorporated into the Testbed Environment for Space Situational Awareness (TESSA). TESSA is based on a flexible, scalable architecture, designed to exploit high-performance computing resources and allow physics-based simulation of the SSA enterprise. In addition to the radar models, TESSA includes hydrodynamic models of satellite intercept and debris generation, orbital propagation algorithms, optical brightness calculations, optical system models, object detection algorithms, orbit determination algorithms, simulation analysis and visualization tools. Within this framework, observations and tracks generated by the new radar model are compared to results from a phenomenological radar model. In particular, the new model will be

  14. Six-Port Based Interferometry for Precise Radar and Sensing Applications

    OpenAIRE

    Alexander Koelpin; Fabian Lurz; Sarah Linz; Sebastian Mann; Christoph Will; Stefan Lindner

    2016-01-01

    Microwave technology plays a more important role in modern industrial sensing applications. Pushed by the significant progress in monolithic microwave integrated circuit technology over the past decades, complex sensing systems operating in the microwave and even millimeter-wave range are available for reasonable costs combined with exquisite performance. In the context of industrial sensing, this stimulates new approaches for metrology based on microwave technology. An old measurement princi...

  15. Ultra-Wideband Radar for Breath Tracking with Optical Fiber for Remote Reach Extension

    DEFF Research Database (Denmark)

    Suhr, Lau Frejstrup; Tafur Monroy, Idelfonso; Vegas Olmos, Juan José

    2016-01-01

    We report on the experimental demonstration of an UWB radar with fiber extension for remote breath tracking through 10 cm of concrete. The radar is based on telecom class equipment.......We report on the experimental demonstration of an UWB radar with fiber extension for remote breath tracking through 10 cm of concrete. The radar is based on telecom class equipment....

  16. Research on Total Station Based Airborne Radar Calibration%电子全站仪机载雷达标校系统研究与开发

    Institute of Scientific and Technical Information of China (English)

    王仲夏; 居鹏; 吴蓉

    2013-01-01

    针对机载雷达标校问题,研究基于电子全站仪的三维坐标测量数据采集技术,开发了一套适合机载雷达方位角和俯仰角的精确标校系统,该系统具有设备简单,安装便捷,容易操作,精度高等优点.测试结果表明该机载雷达标校系统完全满足实际应用的技术要求.%For airborne radar calibration,based on electronic total station,the measurement data of three-dimensional coordinates acquisition technology was studied,a set of suitable azimuth angle and pitch angle precision calibration system for airborne radar was developed,the system has the advantages of simple equipment,convenient installation,easy operation and high precision.Test results show that the airborne radar calibration system completely satisfies application requirements.

  17. Design of reversing radar based on SCM%基于单片机的倒车雷达设计

    Institute of Scientific and Technical Information of China (English)

    赵日峰; 马艳艳

    2012-01-01

    在此设计了一种基于单片机的倒车雷达系统,该系统采用超声波传感器将40 kHz的机械波发射到空气中,经障碍物反射后被超声波传感器接收,对接收后的信号进行放大,并对其进行信号处理.最后将处理后的信号输入到单片机中,通过单片机的显示器输出距离,并比较输出距离与1 m,0.5m的关系,分别发出不同的警报,即通过单片机及其外围部件测量车和障碍物间的距离,最终实现引导驾驶员倒车的功能.经测试,该系统具有精确度高,成本低等优点.%A reversing radar system based on SCM is designed in this paper. The ultrasonic wave sensor is adopted in this system to emit mechanical wave of 40 kHz into the air and to receive it reflected by barriers. The received signal is amplified, processed, and then inputted into SCM. The distance is output on the display on SCM, and then compared with 1 m and 0. 5 m. The different alerts according to the comparison results are issued. That is, the distance between the car and barrier is detected by SCM and the peripheral components. The reversing function that guides drivers to back-up their cars is realized. The testing result shows that the system has the advances of high accuracy and low cost.

  18. Distributed MIMO Radar for Imaging and High Resolution Target Localization

    Science.gov (United States)

    2012-02-02

    SIMO ) radar systems, based on the BLUE, is provided in [20]. The best achievable accuracy for both configurations is derived. MIMO radar systems with...coherent processing are shown to benefit from higher spatial advantage, compared with SIMO systems. The advantage of the MIMO radar scheme over SIMO

  19. Method of deinterleaving radar signal based on PRI transform algorithm%一种基于PRI变换的雷达信号分选方法

    Institute of Scientific and Technical Information of China (English)

    王海滨; 马琦

    2013-01-01

    With the signal environment of information warfare increasingly complicated, the radar signal sorting technology, as one of development directions of modern radar, is of great importance to radar reconnaissance. Several radar signal deinterleav-ing methods are proposed based on PRI parameter. The traditional PRI transform can overcome the subharmonic problem pro-duced in the histogram statistic methods, but has a poor performance on anti-jitter. The paper begins with a discussion of the im-proved PRI transform which overcomes the disadvantages of traditional PRI method effectively, followed by the description of the algorithm simulation. Finally, a method for sorting pulse repetition intervals of staggered PRI is discussed.%信息作战环境日益复杂,而雷达信号分选技术是作为现代信息对抗领域的重要发展方向之一,对于雷达侦察非常重要.对于雷达信号分选,基于PRI参数提出了很多分选方法.传统的PRI变换能克服直方图统计法中的子谐波问题,但抗抖动性差.讨论了修正的PRI变换分选算法,有效地克服了传统PRI变换的缺点,并对算法进行了计算机仿真.最后还讨论了重频参差抖动脉冲序列的分选方法.

  20. IF signals simulation of three-dimensional radar

    Institute of Scientific and Technical Information of China (English)

    Zhang Wei; Wang Xuegang; Zhu Zhaoda

    2008-01-01

    Based on the analysis of the principles of frequency-phase scanning 3-D (three-dimensional) radar and the scattering mechanism of 3-D radar, the target and clutter IF (intermediate frequency) signals model of frequencyphase scanning 3-D radar is presented. The IF signals model of different channels of 3-D radar is presented in one simple formula in which complex waveform effects are considered. The simulation results obtained during tests are also provided in the end.

  1. Underground object characterization based on neural networks for ground penetrating radar data

    Science.gov (United States)

    Zhang, Yu; Huston, Dryver; Xia, Tian

    2016-04-01

    In this paper, an object characterization method based on neural networks is developed for GPR subsurface imaging. Currently, most existing studies demonstrate detecting and imaging objects of cylindrical shapes. While in this paper, no restriction is imposed on the object shape. Three neural network algorithms are exploited to characterize different types of object signatures, including object shape, object material, object size, object depth and subsurface medium's dielectric constant. Feature extraction is performed to characterize the instantaneous amplitude and time delay of the reflection signal from the object. The characterization method is evaluated utilizing the data synthesized with the finite-difference timedomain (FDTD) simulator.

  2. Coastal Wind Analysis Based on Active Radar in Qingdao for Olympic Sailing Event

    Science.gov (United States)

    Cartalis, C.; Stathopoulou, M.; Iacovides, S.; Stratoulias, D.; Karvounis, G.; Helmi, A.

    2008-04-01

    The impact of a major sporting event, such as the Olympic Games, is assessed for the city of Athens which hosted the Olympic Games in 2004. A special indicator depicting the quality of life in an urban environment is defined and applied so as to assess changes prior and after the Olympic Games for Athens. The estimation of the indicator is based to satellite and ground data. It is found that several areas of the overall urban agglomeration of Athens enjoy an improvement in the quality of life indicator. This is mostly due to the hosting of sporting and non sporting Olympic venues as well as due to urban regeneration and transport projects.

  3. Weather Radar Impact Zones

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data represent an inventory of the national impacts of wind turbine interference with NEXRAD radar stations. This inventory was developed by the NOAA Radar...

  4. Antenna array characterisation and signal processing for an FM radio-based passive coherent location radar system

    NARCIS (Netherlands)

    Belfiori, F.; Monni, S.; Rossum, W.L. van; Hoogeboom, P.

    2012-01-01

    The design of passive coherent location radar, which exploits broadcasting transmitters of opportunity in the very high frequency (VHF) radio bandwidth, is presented. Here, the authors primarily focus on the system set-up and on the digital pre-processing steps. Emphasis is given to the antenna sect

  5. Six-Port Based Interferometry for Precise Radar and Sensing Applications.

    Science.gov (United States)

    Koelpin, Alexander; Lurz, Fabian; Linz, Sarah; Mann, Sebastian; Will, Christoph; Lindner, Stefan

    2016-09-22

    Microwave technology plays a more important role in modern industrial sensing applications. Pushed by the significant progress in monolithic microwave integrated circuit technology over the past decades, complex sensing systems operating in the microwave and even millimeter-wave range are available for reasonable costs combined with exquisite performance. In the context of industrial sensing, this stimulates new approaches for metrology based on microwave technology. An old measurement principle nearly forgotten over the years has recently gained more and more attention in both academia and industry: the six-port interferometer. This paper reviews the basic concept, investigates promising applications in remote, as well as contact-based sensing and compares the system with state-of-the-art metrology. The significant advantages will be discussed just as the limitations of the six-port architecture. Particular attention will be paid to impairment effects and non-ideal behavior, as well as compensation and linearization concepts. It will be shown that in application fields, like remote distance sensing, precise alignment measurements, as well as interferometrically-evaluated mechanical strain analysis, the six-port architecture delivers extraordinary measurement results combined with high measurement data update rates for reasonable system costs. This makes the six-port architecture a promising candidate for industrial metrology.

  6. Six-Port Based Interferometry for Precise Radar and Sensing Applications

    Directory of Open Access Journals (Sweden)

    Alexander Koelpin

    2016-09-01

    Full Text Available Microwave technology plays a more important role in modern industrial sensing applications. Pushed by the significant progress in monolithic microwave integrated circuit technology over the past decades, complex sensing systems operating in the microwave and even millimeter-wave range are available for reasonable costs combined with exquisite performance. In the context of industrial sensing, this stimulates new approaches for metrology based on microwave technology. An old measurement principle nearly forgotten over the years has recently gained more and more attention in both academia and industry: the six-port interferometer. This paper reviews the basic concept, investigates promising applications in remote, as well as contact-based sensing and compares the system with state-of-the-art metrology. The significant advantages will be discussed just as the limitations of the six-port architecture. Particular attention will be paid to impairment effects and non-ideal behavior, as well as compensation and linearization concepts. It will be shown that in application fields, like remote distance sensing, precise alignment measurements, as well as interferometrically-evaluated mechanical strain analysis, the six-port architecture delivers extraordinary measurement results combined with high measurement data update rates for reasonable system costs. This makes the six-port architecture a promising candidate for industrial metrology.

  7. A Gaussian Random Field Approach for Merging Radar and Ground-Based Rainfall Data on Small Spatial and Temporal Scales

    Science.gov (United States)

    Krebsbach, K.; Friederichs, P.

    2014-12-01

    The generation of reliable precipitation products that explicitly account for spatial and temporal structures of precipitation events requires a combination of data with a variety of error structures and temporal resolutions. In-situ measurements are relatively accurate, but available only at sparse and irregularly distributed locations, whereas remote measurements cover areas but suffer from spatially and temporally inhomogeneous systematic errors. Besides gauge measurements are available on coarser spatial and temporal resolution in contrast to remote sensing measurements which are given on a fine spatial and temporal resolution. In our study we use precipitation rates from the composit of two X-band radars in Bonn and Jülich in Germany. Our aim is to formulate a statistical space-time model that aggregates and disaggregates precipitation rates from radar and gauge observations. We model a Gaussian random field as underlying process, where we face the task of dealing with a large non-Gaussian data set. To start the analysis of the unadjusted radar rainfall rates, we follow the work of D. Allcroft and C. Glasbey (2003) and transform the data to a truncated Gaussian distribution. The advantage of the latent variable approach is that it takes account of the occurence of rainfall and the intensity using a single process. We proceed by estimating the empirical correlation from these transformed values with maximum likelihood methods and fit a parametric correlation function that gives rise to a Gaussian random field. Since the transformation gives censored values to dry locations, we simulate values for this area that lie below some threshold and extend the Gaussian field to the whole domain. In order to merge gauge and radar data for precipitation, we first aggregate the data to a scale on which the comparison is reasonable and then disaggregate again back to smaller desirable scales. The disaggregation step consists of calculating the difference between radar

  8. Digital LPI Radar Detector

    OpenAIRE

    Ong, Peng Ghee; Teng, Haw Kiad

    2001-01-01

    Approved for public release; distribution is unlimited The function of a Low Probability ofIntercept (LPI) radar is to prevent its interception by an Electronic Support (ES) receiver. This objective is generally achieved through the use of a radar waveform that is mismatched to those waveforms for which an ES receiver is tuned. This allows the radar to achieve a processing gain, with respect to the ES receiver, that is equal to the time-bandwidth product ofthe radar waveform. This...

  9. Weather radar rainfall data in urban hydrology

    DEFF Research Database (Denmark)

    Thorndahl, Søren; Einfalt, Thomas; Willems, Patrick

    2017-01-01

    Application of weather radar data in urban hydrological applications has evolved significantly during the past decade as an alternative to traditional rainfall observations with rain gauges. Advances in radar hardware, data processing, numerical models, and emerging fields within urban hydrology...... necessitate an updated review of the state of the art in such radar rainfall data and applications. Three key areas with significant advances over the past decade have been identified: (1) temporal and spatial resolution of rainfall data required for different types of hydrological applications, (2) rainfall...... estimation, radar data adjustment and data quality, and (3) nowcasting of radar rainfall and real-time applications. Based on these three fields of research, the paper provides recommendations based on an updated overview of shortcomings, gains, and novel developments in relation to urban hydrological...

  10. Regional Prediction of Impending Debris Flow Based on Doppler Weather Radar

    Institute of Scientific and Technical Information of China (English)

    JIANG Yuhong; WEI Fangqiang; ZHANG Jinghong; GU Linkang; DENG Bo; LIU Hongjiang

    2007-01-01

    Debris flow prediction is one of the important means to reduce the loss caused by debris flow. This paper built a regional prediction model of impending debris flow based on regional environmentalbackground (including topography, geology, land use, and etc.), rainfalland debris flow data. A system of regional prediction of impending debris flow was set up on ArcGIS 9.0 platform according to the model.The system used forecast precipitation data of Doppler weather radarand observational precipitation data as its input data. It could provide aprediction about the possibility of debris flow one to three hours beforeit happened, and was put into use in Liangshan Meteorological Observatory in Sichuan province in the monsoon of 2006.

  11. Study on moving target detection to passive radar based on FM broadcast transmitter

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Target detection by a noncooperative illuminator is a topic of general interest in the electronic warfare field.First of all,direct-path interference(DPI)suppression which is the technique of bottleneck of moving target detection by a noncooperative frequency modulation(FM) broadcast transmitter is analyzed in this article;Secondly,a space-time-frequency domain synthetic solution to this problem is introduced:Adaptive nulling array processing is considered in the space domain,DPI cancellation based on adaptive fractional delay interpolation(AFDI)technique is used in planned time domain,and long-time coherent integration is utilized in the frequency domain;Finally,an experimental system is planned by considering FM broadcast transmitter as a noncooperative illuminator,Simulation results by real collected data show that the proposed method has a better performance of moving target detection.

  12. Network radar countermeasure systems integrating radar and radar countermeasures

    CERN Document Server

    Jiang, Qiuxi

    2016-01-01

    This is the very first book to present the network radar countermeasure system. It explains in detail the systematic concept of combining radar and radar countermeasures from the perspective of the information acquisition of target location, the optimization of the reconnaissance and detection, the integrated attack of the signals and facilities, and technological and legal developments concerning the networked system. It achieves the integration of the initiative and passivity, detection and jamming. The book explains how the system locates targets, completes target identification, tracks targets and compiles the data.

  13. A proposal on the study of solar-terrestrial coupling processes with atmospheric radars and ground-based observation network

    Science.gov (United States)

    Tsuda, Toshitaka; Yamamoto, Mamoru; Hashiguchi, Hiroyuki; Shiokawa, Kazuo; Ogawa, Yasunobu; Nozawa, Satonori; Miyaoka, Hiroshi; Yoshikawa, Akimasa

    2016-09-01

    The solar energy can mainly be divided into two categories: the solar radiation and the solar wind. The former maximizes at the equator, generating various disturbances over a wide height range and causing vertical coupling processes of the atmosphere between the troposphere and middle and upper atmospheres by upward propagating atmospheric waves. The energy and material flows that occur in all height regions of the equatorial atmosphere are named as "Equatorial Fountain." These processes from the bottom also cause various space weather effects, such as satellite communication and Global Navigation Satellite System positioning. While, the electromagnetic energy and high-energy plasma particles in the solar wind converge into the polar region through geomagnetic fields. These energy/particle inflow results in auroral Joule heating and ion drag of the atmosphere particularly during geomagnetic storms and substorms. The ion outflow from the polar ionosphere controls ambient plasma constituents in the magnetosphere and may cause long-term variation of the atmosphere. We propose to clarify these overall coupling processes in the solar-terrestrial system from the bottom and from above through high-resolution observations at key latitudes in the equator and in the polar region. We will establish a large radar with active phased array antenna, called the Equatorial Middle and Upper atmosphere radar, in west Sumatra, Indonesia. We will participate in construction of the EISCAT_3D radar in northern Scandinavia. These radars will enhance the existing international radar network. We will also develop a global observation network of compact radio and optical remote sensing equipment from the equator to polar region.

  14. Radar: Human Safety Net

    Science.gov (United States)

    Ritz, John M.

    2016-01-01

    Radar is a technology that can be used to detect distant objects not visible to the human eye. A predecessor of radar, called the telemobiloscope, was first used to detect ships in the fog in 1904 off the German coast. Many scientists have worked on the development and refinement of radar (Hertz with electromagnetic waves; Popov with determining…

  15. Stepped-frequency radar sensors theory, analysis and design

    CERN Document Server

    Nguyen, Cam

    2016-01-01

    This book presents the theory, analysis and design of microwave stepped-frequency radar sensors. Stepped-frequency radar sensors are attractive for various sensing applications that require fine resolution. The book consists of five chapters. The first chapter describes the fundamentals of radar sensors including applications followed by a review of ultra-wideband pulsed, frequency-modulated continuous-wave (FMCW), and stepped-frequency radar sensors. The second chapter discusses a general analysis of radar sensors including wave propagation in media and scattering on targets, as well as the radar equation. The third chapter addresses the analysis of stepped-frequency radar sensors including their principles and design parameters. Chapter 4 presents the development of two stepped-frequency radar sensors at microwave and millimeter-wave frequencies based on microwave integrated circuits (MICs), microwave monolithic integrated circuits (MMICs) and printed-circuit antennas, and discusses their signal processing....

  16. An EBSPK-/MPPSK-Modem Based Transceiver for Radar-Communications

    Directory of Open Access Journals (Sweden)

    Yu Yao

    2015-01-01

    Full Text Available A joint communication and ranging system would constitute a unique platform for future weapon platform or intelligent transportation system to affect the essential tasks of Identification Friend or Foe (IFF system and location sharing services, in terms of both spectrum efficiency and cost effectiveness. In this paper, the design of efficient modulation system which is suitable for simultaneously performing both data transmission and range measurement is proposed. The approach is based on extended binary phase shift keying (EBPSK or M-ary Position Phase Shift Keying (MPPSK modulated waveforms utilized in digital communication. In particular, requirements that allow for employing such signals for range measurements are investigated. Also, Constant False Alarm Rate (CFAR target detection performances of the new proposed system are discussed when target velocity and time delay take different values. Moreover, Doppler tolerance range of impacting filter for demodulating EBPSK/MPPSK pulse signal at 10 GHz is considered. In addition to theoretical considerations, the paper presents simulations and measurement results of the new systems, demonstrating the high spectral utilization of integrated communication and ranging applications.

  17. Physically-based Flood Modeling Driven by Radar Rainfall in the Upper Guadalupe River Basin, Texas

    Science.gov (United States)

    Sharif, H. O.; Chintalapudi, S.; El Hassan, A.

    2011-12-01

    The upstream portion of the Guadalupe River Basin (Upper Guadalupe River Basin) is prone to frequent flooding due to its physiographic properties (thin soils, exposed bedrock, and sparse vegetation). The Upper Guadalupe River watershed above Comfort, Texas drains an area of 2,170 square kilometers. This watershed is located at the central part of the Texas Hill Country. This study presents hydrologic analysis of the June 2002, November-2004, and August-2007 flood events that occurred in Upper Guadalupe River Basin. The physically based, distributed-parameter Gridded Surface Subsurface Hydrologic Analysis (GSSHA) hydrologic model was used to simulate the above flooding events. The first event was used in model while the other two were used for validation. GSSHA model was driven by both rain gauge and Multi-sensor Precipitation Estimator (MPE) rainfall inputs. Differences in simulation results were compared in terms of the hydrographs at different locations in the basin as well as the spatial distribution of hydrologic processes. GSSHA simulations driven by MPE rainfall match very well the USGS observed hydrograph. GSSHA simulation driven by rain gauge rainfall for June-2002 storm event underestimated the peak flow.

  18. Radar and wind turbines; Radar en windturbines

    Energy Technology Data Exchange (ETDEWEB)

    Van Doorn, H.

    2010-03-15

    In the last years the developments of wind parks were hampered because of their possible effect on the radar for observation of air traffic. Work is currently being done on a new assessment model for wind turbines under the auspices of the steering group National Security for the military radar systems. Air traffic control Netherlands (LVNL) will look at the options for civil radars to join in. [Dutch] In de afgelopen jaren zijn windparkontwikkelingen onder meer belemmerd vanwege mogelijke effecten op radar voor de waarneming van luchtverkeer. Onder auspicien van de stuurgroep Nationale Veiligheid voor de militaire radarsystemen op land wordt gewerkt aan een nieuw beoordelingsmodel voor windturbines. De Luchtverkeersleiding Nederland (LVNL) zal bezien in hoeverre de civiele radars hierbij kunnen aansluiten.

  19. Scanning ARM Cloud Radar Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Widener, K; Bharadwaj, N; Johnson, K

    2012-06-18

    The scanning ARM cloud radar (SACR) is a polarimetric Doppler radar consisting of three different radar designs based on operating frequency. These are designated as follows: (1) X-band SACR (X-SACR); (2) Ka-band SACR (Ka-SACR); and (3) W-band SACR (W-SACR). There are two SACRs on a single pedestal at each site where SACRs are deployed. The selection of the operating frequencies at each deployed site is predominantly determined by atmospheric attenuation at the site. Because RF attenuation increases with atmospheric water vapor content, ARM's Tropical Western Pacific (TWP) sites use the X-/Ka-band frequency pair. The Southern Great Plains (SGP) and North Slope of Alaska (NSA) sites field the Ka-/W-band frequency pair. One ARM Mobile Facility (AMF1) has a Ka/W-SACR and the other (AMF2) has a X/Ka-SACR.

  20. 一种基于PRI谱特征的复杂雷达信号分选方法%A method of complex radar signal sorting based on PRI spectrum signatures

    Institute of Scientific and Technical Information of China (English)

    王亚莉; 胡进

    2011-01-01

    通过分析雷达截获机所处的复杂雷达信号环境,提出了一种基于PR I谱特征的复杂雷达信号分选方法。该方法利用PR I变换获取雷达信号PR I谱,并根据各种复杂雷达信号PR I谱特征实现复杂雷达信号的分选工作。仿真结果表明,该方法能够较好地实现复杂信号环境下雷达信号的分选工作。%In view of the complex radar signal environment for radar interceptors,a method of the complex radar signal sorting based on the PRI spectrum signatures is presented.The PRI spectrum is obtained through the PRI transform,and the complex radar signal sorting is realized based on the PRI spectrum signatures of various complex radar signals.The simulation results show that the method can better realize radar signal sorting in the complex signal environment.

  1. Habitat mapping of the Brazilian Pantanal using synthetic aperture radar imagery and object based image analysis

    Science.gov (United States)

    Evans, Teresa Lynne

    The Brazilian Pantanal, a continuous tropical wetland located in the center of South America, has been recognized as one of the largest and most important wetland ecosystems globally. The Pantanal exhibits a high biodiversity of flora and fauna species, and many threatened habitats. The spatial distribution of these habitats influence the distribution, abundance and interactions of animal species, and the change or destruction of habitat may cause alteration of key biological processes. The Pantanal may be divided into several distinct subregions based on geology and hydrology: flooding in these subregions is distinctly seasonal, but the timing, amplitude and duration of inundation vary considerably as a result of both the delayed release of floodwaters and regional rainfall patterns. Given the ecological importance of the Pantanal wetland ecosystem, the primary goal of this research was to utilize a dual season set of L-band (ALOS/PALSAR) and C-band (RADARSAT-2 and ENVISAT/ASAR) imagery, a comprehensive set of ground reference data, and a hierarchical object-oriented approach. This primary goal was achieved through two main research tasks. The first task was to define the diverse habitats of the Lower Nhecolândia subregion of the Pantanal at both a fine spatial resolution (12.5 m), and a relatively medium spatial resolution (50 m), thus evaluating the accuracy of the differing spatial resolutions for land cover classification of the highly spatially heterogeneous subregion. The second task was to define on a regional scale, using the 50 m spatial resolution imagery, the wetland habitats of each of the hydrological subregions of the Pantanal, thereby producing a final product covering the entire Pantanal ecosystem. The final classification maps of the Lower Nhecolândia subregion resulted in overall accuracies of 83% and 72% for the 12.5 m and 50 m spatial resolutions, respectively, and defined seven land cover classes. In general, the highest degree of confusion

  2. 基于模糊评价的雷达站模拟训练考核评估方法%Assessment of radar station simulation training based on fuzzy evaluation

    Institute of Scientific and Technical Information of China (English)

    刘东亚; 戴志平; 张勇

    2014-01-01

    Reflecting the training effect of radar station simulation training system objectively and improving the simulation training level of radar units are to realize the requirements of unit training being closer to the actual military combat. Aimed at the assessment issues of radar station simulation training and on the basis of the difference between the radar station professional classes and simulation training subjects, this article proposes the assessment method for radar station simulation training based on fuzzy evaluation. By taking a certain radar station as an evaluation object, the applied analysis of this method is performed and its availability is verified, thus providing a scientific basis for the assessment of radar station simulation training and also laying a base for the assessment software design of the radar station simulation training.%客观反映雷达站模拟训练系统的训练效果,提高雷达兵部队模拟训练水平,是实现部队训练向实战靠拢的要求。针对雷达站模拟训练考核评估问题,依据雷达站专业人员类别和模拟训练科目的区别,提出了基于模糊评价法的雷达站模拟训练考核评估方法。以某雷达站为评估对象,对该方法进行应用分析,验证了方法的可行性。这为雷达站模拟训练考核评估提供了科学的依据,也为雷达站模拟训练考核评估软件的设计奠定了基础。

  3. Highly Integrated Radar Sensor-on-Chip

    Science.gov (United States)

    Mende, Ralph

    2012-05-01

    A highly integrated 24 GHz radar sensor is presented, based on a Radio Frequency Integrated Circuit (RFIC) which was specifically developed for a Frequency Modulated Shift Keying (FMSK) based Radar system design. Antenna, waveform, the Radio Frequency (RF) and Digital Signal Processor (DSP) module, the software design, cost and performance aspects will be described. The significant technical and economical advantages of the implemented Silicon-Germanium (SiGe) Bipolar CMOS (BiCMOS) transceiver are demonstrated. Some automotive and other applications based on this technology and new radar system design will be explained.

  4. Understanding radar systems

    CERN Document Server

    Kingsley, Simon

    1999-01-01

    What is radar? What systems are currently in use? How do they work? This book provides engineers and scientists with answers to these critical questions, focusing on actual radar systems in use today. It is a perfect resource for those just entering the field, or as a quick refresher for experienced practitioners. The book leads readers through the specialized language and calculations that comprise the complex world of radar engineering as seen in dozens of state-of-the-art radar systems. An easy to read, wide ranging guide to the world of modern radar systems.

  5. Measurements of radar ground returns

    NARCIS (Netherlands)

    Loor, G.P. de

    1974-01-01

    The ground based measurement techniques for the determination of the radar back-scatter of vegetation and soils as used in The Netherlands will be described. Two techniques are employed: one covering a large sample area (> 1000 m2) but working at low grazing angels only and one (short range) coverin

  6. Multidimensional radar picture

    Science.gov (United States)

    Waz, Mariusz

    2010-05-01

    In marine navigation systems, the three-dimensional (3D) visualization is often and often used. Echosonders and sonars working in hydroacustic systems can present pictures in three dimensions. Currently, vector maps also offer 3D presentation. This presentation is used in aviation and underwater navigation. In the nearest future three-dimensional presentation may be obligatory presentation in displays of navigation systems. A part of these systems work with radar and communicates with it transmitting data in a digital form. 3D presentation of radar picture require a new technology to develop. In the first step it is necessary to compile digital form of radar signal. The modern navigation radar do not present data in three-dimensional form. Progress in technology of digital signal processing make it possible to create multidimensional radar pictures. For instance, the RSC (Radar Scan Converter) - digital radar picture recording and transforming tool can be used to create new picture online. Using RSC and techniques of modern computer graphics multidimensional radar pictures can be generated. The radar pictures mentioned should be readable for ECDIS. The paper presents a method for generating multidimensional radar picture from original signal coming from radar receiver.

  7. Two-Dimensional Direction-of-Arrival Estimation for Trilinear Decomposition-Based Monostatic Cross MIMO Radar

    Directory of Open Access Journals (Sweden)

    Fangqing Wen

    2013-01-01

    Full Text Available A low complexity monostatic cross multiple-in multiple-out (MIMO radar scheme is proposed in this paper. The minimum-redundancy linear array (MRLA is introduced in the cross radar to improve the efficiency of the array elements. The two-dimensional direction-of-arrival (DOA estimation problem links to the trilinear model, which automatically pairs the estimated two-dimensional angles, requiring neither eigenvalue decomposition of received signal covariance matrix nor spectral peak searching. The proposed scheme performs better than the uniform linear arrays (ULA configuration under the same conditions, and the proposed algorithm has less computational complexity than that of multiple signal classification (MUSIC algorithm. Simulation results show the effectiveness of our scheme.

  8. Radar Time and a State-Space Based Approach To Quantum Field Theory In Gravitational and Electromagnetic Backgrounds

    CERN Document Server

    Dolby, C E; Dolby, Carl E.; Gull, Stephen F.

    2002-01-01

    In a recent paper (hep-th/0103228) a new initial value formulation of fermionic QFT was presented that is applicable to an arbitrary observer in any electromagnetic background. This approach suggests a consistent particle interpretation at all times, with the concept of `radar time' used to generalise this interpretation to an arbitrarily moving observer. In the present paper we extend this formalism to allow for gravitational backgrounds. The observer-dependent particle interpretation generalises Gibbons' definition to non-stationary spacetimes. This allows any observer to be considered, providing a particle interpretation that depends {\\it only} on the observer's motion and the background, not on any choice of coordinates or gauge, or on details of their particle detector. Consistency with known results is demonstrated for the cases of Rindler space and deSitter space. Radar time is also considered for an arbitrarily moving observer in an arbitrary 1+1 dimensional spacetime, and for a comoving observer in a...

  9. 基于DSP的防撞雷达信号采样系统设计%Design of automotive anti-collision radar sampling system based on DSP

    Institute of Scientific and Technical Information of China (English)

    张恒; 刘胜利; 范江涛; 王良

    2012-01-01

    Directed toward the linear frequency modulation continuous wave radar, an ADC which has two simultaneous differential inputs is chosen, and a system based on SPORT port of DSP is designed to sample the I and Q quadrature signals. Tlie system validity is validated via experiments.%针对线性调频连续波汽车防撞雷达回波信号的特点,选用串行差分ADC,设计了一种基于DSP的SPORT口的I、Q双通道采样系统,并通过实验验证了系统的正确性.

  10. Digital Elevation Models of Greenland based on combined radar and laser altimetry as well as high-resolution stereoscopic imagery

    Science.gov (United States)

    Levinsen, J. F.; Smith, B. E.; Sandberg Sorensen, L.; Khvorostovsky, K.; Simonsen, S. B.; Forsberg, R.

    2015-12-01

    A number of Digital Elevation Models (DEMs) of Greenland exist, each of which are applicable for different purposes. This study presents two such DEMs: One developed by merging contemporary radar and laser altimeter data, and one derived from high-resolution stereoscopic imagery. All products are made freely available. The former DEM covers the entire Greenland. It is specific to the year 2010, providing it with an advantage over previous models suffering from either a reduced spatial/ temporal data coverage or errors from surface elevation changes (SEC) occurring during data acquisition. Radar data are acquired with Envisat and CryoSat-2, and laser data with the Ice, Cloud, and land Elevation Satellite, the Land, Vegetation, and Ice Sensor, and the Airborne Topographic Mapper. Correcting radar data for errors from slope effects and surface penetration of the echoes, and merging these with laser data, yields a DEM capable of resolving both surface depressions as well as topographic features at higher altitudes. The spatial resolution is 2 x 2 km, making the DEM ideal for application in surface mass balance studies, SEC detection from radar altimetry, or for correcting such data for slope-induced errors. The other DEM is developed in a pilot study building the expertise to map all ice-free parts of Greenland. The work combines WorldView-2 and -3 as well as GeoEye1 imagery from 2014 and 2015 over the Disko, Narsaq, Tassilaq, and Zackenberg regions. The novelty of the work is the determination of the product specifications after elaborate discussions with interested parties from government institutions, the tourist industry, etc. Thus, a 10 m DEM, 1.5 m orthophotos, and vector maps are produced. This opens to the possibility of using orthophotos with up-to-date contour lines or for deriving updated coastlines to aid, e.g., emergency management. This allows for a product development directly in line with the needs of parties with specific interests in Greenland.

  11. Design and realization of remote monitoring system based on radar networking%基于雷达组网远程监控系统设计与实现

    Institute of Scientific and Technical Information of China (English)

    李华敏; 王瑛; 孙君亮

    2012-01-01

    针对雷达组网系统对远端雷达站监控的需要,提出了一种雷达远程监控系统设计方法.采用高性能TMS320DM642处理器作为系统硬件平台,应用其高速处理性能和片上集成外设端口功能,实现对雷达状态视频信号采集及数据压缩处理,利用其IP端口完成远程数据传输.该系统嵌入远端雷达站,以视频方式收集雷达工作状态信息并上传;雷达组网系统接收并显示各雷达视频信息,实现了远程监控.%According to the requirement on remote radar station monitoring of radar networking system, a new. Design method for the radar remote monitoring system is proposed. The system hardware platform is based on high performance processor TMS320DM642, and uses the high-speed processing performance and video port function to acquire the radar state video signal and process the video data compression. Using the IP port, the data transmission is achieved for long-distance. As the system embedding every beyond radar, the radar work state information is transmitted by video collection. The radar networking system achieves remote monitoring by receiving and showing every radar video information.

  12. Bistatic Radar System Ambiguity Function Analysis Based on Velocity Vector%基于速度矢量的双基地雷达模糊函数分析

    Institute of Scientific and Technical Information of China (English)

    刘勇; 李国君

    2012-01-01

    The bistatic radar system ambiguity function is presented based on monostatic radar system ambiguity function. The bistatic radar system geometry configuration and the targets moving states determine the bistatic radar system ambiguity function features besides the transmitted signal. Supposing transmitting signal is simple Gaussian pulse, the bistatic radar system ambiguity function characterizes different features when target range and velocity vector is changed. The method is suited to any type transmitted pulse. It is valuable to analyze the bistatic radar system resolving and ambiguity of range and veloci-ty.%通过研究双基地雷达系统模糊函数数学模型和当发射信号为高斯单脉冲且目标相对接收机的距离和速度变化时双基地雷达系统模糊函数的特性,分析了目标的速度大小与方向对模糊函数的影响.该模型可有效考核任意发射脉冲信号的双基地雷达系统的分辨力及距离和速度模糊等问题,对研究双基地雷达系统性能有着重要的理论参考价值.

  13. External calibration technique of millimeter-wave cloud radar

    Science.gov (United States)

    Wen, Tao; Zhao, Zeng-Liang; Yao, Zhi-Gang; Han, Zhi-Gang; Guo, Lin-Da

    2016-10-01

    The millimeter-wave cloud radar can provide a large number of fine and reliable information for the inversion of cloud macro and micro parameters. A key link of using the millimeter-wave cloud radar to detect the cloud is that the radar must be calibrated. Due to the precision components and severe environment of millimeter-wave cloud radar, subtle changes may take place in the operation process of cloud radar, unless the cloud radar is calibrated regularly. Although the calibration system inside the cloud radar can track and monitor the main working parameters and correct the detection results, it fails to consider the characteristics of the antenna and the mutual influence among different components of cloud radar. Therefore, the external calibration for cloud radar system is very important. Combined with the actual situation of cloud radar under domestic onboard platform, this paper builds a complete external calibration technique process of cloud radar based on the calm sea, providing the theoretical support for the external calibration experiments of the airborne and even satellite-borne millimeter-wave cloud radar developed by our country.

  14. 基于DRFM技术的雷达标校器设计与实现%Design and Accomplishment of Radar Calibration Equipment Based on DRFM

    Institute of Scientific and Technical Information of China (English)

    刘勇; 李国君

    2011-01-01

    建立了基于数字射频存储器技术构建雷达标校器的方法.该雷达标校器可灵活实现目标运动模拟、多普勒频率加载、目标RCS模拟、多目标模拟等功能,较传统的基于光纤延迟实现的雷达标校器更具有应用价值.针对实际应用需求提出了解决频率捷变的方案,给出了典型模拟策略所需数学模型.应用研究表明,基于数字射频存储器技术的雷达标校器具有较强的工程应用价值和推广价值.%A design making of radar calibration equipment based on digital radio frequency memory (DRFM)technique was presented. The equipment can flexibly accomplish target motion simulation, Doppler frequency loading, target RCS simulation functions and so on. This radar calibration equipment is more practical comparing the calibration equipments using fibre delay. A programmed for settling frequency agility was put forwarded for practical demand. At the same time a mathematics model of typical simulating tactics was brought out. The research results showed that this radar calibration equipment base on digital radio frequency memory (DRFM) had much engineering and realizing values.

  15. Influences of weather phenomena on automotive laser radar systems

    Science.gov (United States)

    Rasshofer, R. H.; Spies, M.; Spies, H.

    2011-07-01

    Laser radar (lidar) sensors provide outstanding angular resolution along with highly accurate range measurements and thus they were proposed as a part of a high performance perception system for advanced driver assistant functions. Based on optical signal transmission and reception, laser radar systems are influenced by weather phenomena. This work provides an overview on the different physical principles responsible for laser radar signal disturbance and theoretical investigations for estimation of their influence. Finally, the transmission models are applied for signal generation in a newly developed laser radar target simulator providing - to our knowledge - worldwide first HIL test capability for automotive laser radar systems.

  16. On detection performance and system configuration of MIMO radar

    Institute of Scientific and Technical Information of China (English)

    TANG Jun; WU Yong; PENG YingNing; WANG XiuTan

    2009-01-01

    Multiple-input multiple-output (MIMO) radar is a new concept with some new characteristics, such as multiple orthogonal waveforms and omnidirectional coverage. Based on Stein's lemma, we use relative entropy as a precise and general measure of error exponent to study detection performance for both MIMO radar and phased array radar. And based on derived analytical results, we further study the system configuration problem of Bistatic MIMO radar systems, where transmitters and receivers are located in different positions. Some interesting results are presented. For phased array radar, when the total numbers of transmitters and receivers are fixed, we should always make the number of transmitters equal to the number of receivers. For MIMO radar, we should use a small number of transmitters in low signal noise ratio (SNR) region, and make the number of transmitters equal to the number of receivers in high SNR region. These results are instructive for deployment of bistatic MIMO radar systems in the future.

  17. Trigonometric bases for matrix weighted <em>Lp>-spaces

    DEFF Research Database (Denmark)

    Nielsen, Morten

    2010-01-01

    We give a complete characterization of 2π-periodic matrix weights W for which the vector-valued trigonometric system forms a Schauder basis for the matrix weighted space Lp(T;W). Then trigonometric quasi-greedy bases for Lp(T;W) are considered. Quasi-greedy bases are systems for which the simple ...

  18. Specific PCR-based detection of <em>Alternaria helianthiem>

    DEFF Research Database (Denmark)

    Udayashankar, A.C.; Nayaka, S. Chandra; Archana, B.;

    2012-01-01

    Alternaria helianthi is an important seed-borne pathogenic fungus responsible for blight disease in sunflower. The current detection methods, which are based on culture and morphological identification, are time-consuming, laborious and are not always reliable. A PCR-based diagnostic method...

  19. AS BASES EMPÍRICAS DA MORAL EM HUME

    OpenAIRE

    Bruno Martinez Portela

    2012-01-01

    A presente dissertação tem como objetivo investigar a teoria moral de David Hume a partir de seu método empírico. Para isso, é necessária a análise de sua crítica ao racionalismo e à metafísica como métodos para a fundamentação moral, a apresentação do método empírico como possibilidade de fundamentação teórica da moral e a exposição de sua teoria moral no contexto de seu sistema filosófico. Pretende-se, portanto, demonstrar por que em Hume a razão por si só é insuficiente para...

  20. Study of signal recognition of radar emitter based on QPSO%基于QPSO的雷达辐射源信号识别方法研究

    Institute of Scientific and Technical Information of China (English)

    郭戈; 徐佳婧; 徐璟; 魏洁

    2014-01-01

    鉴于支持向量机(SVM)方法对雷达辐射源信号具有较理想的识别结果,但对模型参数没有具体选择方法的问题,设计了一种以具有量子行为的粒子群优化(QPSO)算法为参数优化方法的SVM分类器,并提出了基于QPSO-SVM的雷达辐射源信号识别方法.QPSO-SVM分类器在采用QPSO算法对SVM进行优化改进的同时,继承了SVM分类器泛化能力强的特点,对雷达辐射源信号识别问题具有良好的适应性.实验结果表明,与其他方法相比,本文方法在保证识别准确率的同时,降低了参数选择时间.%Considering that the SVM algorithm has an ideal recognition result for radar emitter signals, but no specific selection method for the model parameters, this paper designs an SVM classifier that uses QPSO algorithm as the optimization algorithm of parameters, and proposes a scheme of signal recognition of radar emitter based on QPSO-SVM. While the QPSO-SVM classifier optimizes and improves SVM using the QPSO algorithm, the proposed classifier keeps the strong generalization capability of SVM classifier, thus having the better adaptability for the signal recognition of radar emitter. Experimental results show that this proposed method can shorten the time for parameter selection while guaranteeing the accuracy rate of recognition, compared with other algorithms.

  1. National Prehospital Evidence-Based Guidelines Strategy: A Summary for EMS Stakeholders.

    Science.gov (United States)

    Martin-Gill, Christian; Gaither, Joshua B; Bigham, Blair L; Myers, J Brent; Kupas, Douglas F; Spaite, Daniel W

    2016-01-01

    Multiple national organizations have recommended and supported a national investment to increase the scientific evidence available to guide patient care delivered by Emergency Medical Services (EMS) and incorporate that evidence directly into EMS systems. Ongoing efforts seek to develop, implement, and evaluate prehospital evidence-based guidelines (EBGs) using the National Model Process created by a multidisciplinary panel of experts convened by the Federal Interagency Committee on EMS (FICEMS) and the National EMS Advisory Council (NEMSAC). Yet, these and other EBG efforts have occurred in relative isolation, with limited direct collaboration between national projects, and have experienced challenges in implementation of individual guidelines. There is a need to develop sustainable relationships among stakeholders that facilitate a common vision that facilitates EBG efforts. Herein, we summarize a National Strategy on EBGs developed by the National Association of EMS Physicians (NAEMSP) with involvement of 57 stakeholder organizations, and with the financial support of the National Highway Traffic Safety Administration (NHTSA) and the EMS for Children program. The Strategy proposes seven action items that support collaborative efforts in advancing prehospital EBGs. The first proposed action is creation of a Prehospital Guidelines Consortium (PGC) representing national medical and EMS organizations that have an interest in prehospital EBGs and their benefits to patient outcomes. Other action items include promoting research that supports creation and evaluates the impact of EBGs, promoting the development of new EBGs through improved stakeholder collaboration, and improving education on evidence-based medicine for all prehospital providers. The Strategy intends to facilitate implementation of EBGs by improving guideline dissemination and incorporation into protocols, and seeks to establish standardized evaluation methods for prehospital EBGs. Finally, the Strategy

  2. Low Bandwidth Vocoding using EM Sensor and Acoustic Signal Processing

    Energy Technology Data Exchange (ETDEWEB)

    Ng, L C; Holzrichter, J F; Larson, P E

    2001-10-25

    Low-power EM radar-like sensors have made it possible to measure properties of the human speech production system in real-time, without acoustic interference [1]. By combining these data with the corresponding acoustic signal, we've demonstrated an almost 10-fold bandwidth reduction in speech compression, compared to a standard 2.4 kbps LPC10 protocol used in the STU-III (Secure Terminal Unit, third generation) telephone. This paper describes a potential EM sensor/acoustic based vocoder implementation.

  3. A MoLC+MoM-based G0distribution parameter estimation method with application to synthetic aperture radar target detection

    Institute of Scientific and Technical Information of China (English)

    朱正为; 周建江; 郭玉英

    2015-01-01

    The accuracy of background clutter model is a key factor which determines the performance of a constant false alarm rate (CFAR) target detection method. G0 distribution is one of the optimal statistic models in the synthetic aperture radar (SAR) image background clutter modeling and can accurately model various complex background clutters in the SAR images. But the application of the distribution is greatly limited by its disadvantages that the parameter estimation is complex and the local detection threshold is difficult to be obtained. In order to solve the above-mentioned problems, an synthetic aperture radar CFAR target detection method using the logarithmic cumulant (MoLC) + method of moment (MoM)-based G0distribution clutter model is proposed. In the method, G0 distribution is used for modeling the background clutters, a new MoLC+MoM-based parameter estimation method coupled with a fast iterative algorithm is used for estimating the parameters of G0 distribution and an exquisite dichotomy method is used for obtaining the local detection threshold of CFAR detection, which greatly improves the computational efficiency, detection performance and environmental adaptability of CFAR detection. Experimental results show that the proposed SAR CFAR target detection method has good target detection performance in various complex background clutter environments.

  4. Low-Rank Matrix Recovery Approach for Clutter Rejection in Real-Time IR-UWB Radar-Based Moving Target Detection.

    Science.gov (United States)

    Sabushimike, Donatien; Na, Seung You; Kim, Jin Young; Bui, Ngoc Nam; Seo, Kyung Sik; Kim, Gil Gyeom

    2016-09-01

    The detection of a moving target using an IR-UWB Radar involves the core task of separating the waves reflected by the static background and by the moving target. This paper investigates the capacity of the low-rank and sparse matrix decomposition approach to separate the background and the foreground in the trend of UWB Radar-based moving target detection. Robust PCA models are criticized for being batched-data-oriented, which makes them inconvenient in realistic environments where frames need to be processed as they are recorded in real time. In this paper, a novel method based on overlapping-windows processing is proposed to cope with online processing. The method consists of processing a small batch of frames which will be continually updated without changing its size as new frames are captured. We prove that RPCA (via its Inexact Augmented Lagrange Multiplier (IALM) model) can successfully separate the two subspaces, which enhances the accuracy of target detection. The overlapping-windows processing method converges on the optimal solution with its batch counterpart (i.e., processing batched data with RPCA), and both methods prove the robustness and efficiency of the RPCA over the classic PCA and the commonly used exponential averaging method.

  5. Detecting and mitigating wind turbine clutter for airspace radar systems.

    Science.gov (United States)

    Wang, Wen-Qin

    2013-01-01

    It is well recognized that a wind turbine has a large radar cross-section (RCS) and, due to the movement of the blades, the wind turbine will generate a Doppler frequency shift. This scattering behavior may cause severe interferences on existing radar systems including static ground-based radars and spaceborne or airborne radars. To resolve this problem, efficient techniques or algorithms should be developed to mitigate the effects of wind farms on radars. Herein, one transponder-based mitigation technique is presented. The transponder is not a new concept, which has been proposed for calibrating high-resolution imaging radars. It modulates the radar signal in a manner that the retransmitted signals can be separated from the scene echoes. As wind farms often occupy only a small area, mitigation processing in the whole radar operation will be redundant and cost inefficient. Hence, this paper uses a transponder to determine whether the radar is impacted by the wind farms. If so, the effects of wind farms are then mitigated with subsequent Kalman filtering or plot target extraction algorithms. Taking airborne synthetic aperture radar (SAR) and pulse Doppler radar as the examples, this paper provides the corresponding system configuration and processing algorithms. The effectiveness of the mitigation technique is validated by numerical simulation results.

  6. 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.

  7. Phased-array radar design application of radar fundamentals

    CERN Document Server

    Jeffrey, Thomas

    2009-01-01

    Phased-Array Radar Design is a text-reference designed for electrical engineering graduate students in colleges and universities as well as for corporate in-house training programs for radar design engineers, especially systems engineers and analysts who would like to gain hands-on, practical knowledge and skills in radar design fundamentals, advanced radar concepts, trade-offs for radar design and radar performance analysis.

  8. Passive MIMO Radar Detection

    Science.gov (United States)

    2013-09-01

    from history to future”. Proc. 11th Int. Radar Symp. (IRS), 1–4. 2010. [58] Levanon, N. “ Interferometry against differential Doppler: performance...2141, 2013. [71] Richards, M. A., J. A. Scheer, and W. A. Holm. Principles of Modern Radar , volume 1. SciTech Publishing, Inc., 2010. [72] Scharf, L...PASSIVE MIMO RADAR DETECTION DISSERTATION Daniel E. Hack, Civilian AFIT-ENG-DS-13-S-07 DEPARTMENT OF THE AIR FORCE AIR UNIVERSITY AIR FORCE INSTITUTE

  9. Environmental Assessment for the Radar Tomography Range and Equipment Storage Facility, Wright-Patterson Air Force Base, Ohio

    Science.gov (United States)

    2012-10-01

    tower ring and equipment storage facility footprint. Proximity to Runway 05R/23L and clear zones for hot cargo pad , Huffman Prairie National Historic...Any tree clearing activities would occur between September 30 and April 1 to avoid the summer maternity season ofthe Indiana bat. In accordance with...ft  concrete  pad  and placed approximately 300 ft from the tower ring. The interior space is a laboratory for  radar testing and a garage/storage area

  10. Parametric Sparse Representation and Its Applications to Radar Sensing

    Directory of Open Access Journals (Sweden)

    Li Gang

    2016-02-01

    Full Text Available Sparse signal processing has been utilized to the area of radar sensing. Due to the presence of unknown factors such as the motion of the targets of interest and the error of the radar trajectory, a predesigned dictionary cannot provide the optimally spare representation of the actual radar signals. This paper will introduce a method called parametric sparse representation, which is a special case of dictionary learning and can dynamically learn the unknown factors during the radar sensing and achieve the optimally sparse representation of radar signals. This paper will also introduce the applications of parametric sparse representation to Inverse Synthetic Aperture Radar imaging (ISAR imaging, Synthetic Aperture Radar imaging (SAR autofocusing and target recognition based on micro-Doppler effect.

  11. Signal processing method of a novel polarized array radar seeker

    Institute of Scientific and Technical Information of China (English)

    Lizhong Song; Xiaolin Qiao

    2013-01-01

    This paper proposes a novel polarized radar seeker based on the polarized antenna array. A ful y polarized signal processing method for the proposed radar seeker is studied un-der the environments with electromagnetic interferences. A dual polarized antenna array is employed to transmit and receive the radar signals. The instantaneous polarization signal processing technique is used to detect and recognize the targets. The di-rection of arrival (DOA) of the target is measured through the spatial spectrum with high resolution for the polarized array radar seeker system. The ful y polarized signal model of the polarized array radar seeker is formulated and a specific signal processing algorithm is expounded. The theoretical research and numerical simulation results demonstrate that the proposed radar seeker has good performances in target detection and electronic warfare. The research results can provide an effective technical approach to develop and research the new generation radar seeker.

  12. Radar Signature Calculation Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: The calculation, analysis, and visualization of the spatially extended radar signatures of complex objects such as ships in a sea multipath environment and...

  13. EM-Based Optimization Exploiting Partial Space Mapping and Exact Sensitivities

    DEFF Research Database (Denmark)

    Bandler, J. W.; Mohamed, A. S.; Bakr, M. H.

    2002-01-01

    We present a family of robust techniques for exploiting sensitivities in EM-based circuit optimization through Space Mapping (SM). We utilize derivative Information for parameter extractions and mapping updates. We exploit a Partial Space Mapping (PSM) concept where a reduced set of parameters...

  14. EM-based optimization exploiting partial space mapping and exact sensitivities

    DEFF Research Database (Denmark)

    Bandler, John W.; Mohamed, Achmed S.; Bakr, Mohamed H.

    2002-01-01

    We present a family of robust techniques for exploiting sensitivities in electromagnetic (EM)-based circuit optimization through space mapping (SM) technology. We utilize derivative information for parameter extractions and mapping updates. We exploit a partial SM (PSM) concept, where a reduced set...

  15. Design of high-precision and multi-channel radar generator based on AD9959%基才AD9959的高精度多通道雷达信号源设计

    Institute of Scientific and Technical Information of China (English)

    宋征; 许国宏; 李星

    2012-01-01

    In order to ensure precision of power synthesize in phased array radar, a kind of high-precision multi-channel radar generator based on AD9959 is designed. Radar generator use host computer and FPGA to control ad9959 and Produce 32 channel sine wave.linear frequency modulation and encoding and so on, designed a multi--channel signal amplitude and phase measuring and adjustment system using ad8302. The radar generator have been applied in ,project, and the experimental results showed that the radar generator had several advantages such as high frequency stability, high precise of phase amplitude consistency, which fully meet the techinical requirements and performance index of the radar generator in phased array radar.%现代相控阵雷达为了保证空间功率合成精度需要高精度的雷达信号。设计实现了一种以AD9959为核心的高精度多通道雷达信号源。信号源利用多片AD9959产生32路正弦波、线性调频以及相位编码等多种信号形式.并设计采用AD8302对多路信号的幅度和相位进行检测与调整。该信号源已应用实际工程中,现场实验结果表明,该信号源系统产生的高频信号频率稳定度高、相位幅度一致性好,完全满足对信号源的性能指标的要求。

  16. Characterization and discrimination of evolving mineral and plant oil slicks based on L-band synthetic aperture radar (SAR)

    Science.gov (United States)

    Jones, Cathleen E.; Espeseth, Martine M.; Holt, Benjamin; Brekke, Camilla; Skrunes, Stine

    2016-10-01

    Evolution of the damping ratio for Bragg wavenumbers in the range 32-43 rad/m is evaluated for oil slicks of different composition released in the open ocean and allowed to develop naturally. The study uses quad-polarimetric L-band airborne synthetic aperture radar data acquired over three mineral oil emulsion releases of different, known oil-to-water ratio, and a near-coincident release of 2-ethylhexyl oleate that served as a biogenic look-alike. The experiment occurred during the 2015 Norwegian oil-on-water exercise in the North Sea during a period of relatively high winds ( 12 m/s). NASA's Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) was used to repeatedly image the slicks over a period of eight hours, capturing the slicks' early development and providing a time series from which to track the evolution of the slicks' size, position, and radiometric characteristics. Particular emphasis is given in this analysis to identification of zones of higher damping ratio within the slicks (zoning) as potential indicators of thicker oil, and to comparison of the evolution of emulsion and plant oil damping ratios. It was found that all mineral oil slicks initially exhibited zoning apparent in VV, HH, and HV intensities, and that the areas of higher damping ratio persisted the longest for the highest oil content emulsion (80% oil by volume). In contrast, zoning was not unambiguously evident for plant oil at any time from 44 minutes to 8.5 hours after release.

  17. Multiparameter radar and aircraft based studies of microphysical, kinematic, and electrical structure of convective clouds during CaPE

    Science.gov (United States)

    Bringi, V. N.

    1994-03-01

    Two storms from the 9 August, 1991 CaPE case were analyzed in-depth focusing on multiparameter radar signature evolution over 60 min. in coordination with 24 aircraft penetrations which provided particle image and electric field data together with vertical air motion, cloud water and other state parameters. A total of five discrete 'cells' were identified in the two storms and their life cycle fully documented. Collaboration with South Dakota School of Mines and University of Alabama at Huntsville has resulted in a full integration of aircraft image and field mill data (from SDSM&T T-28 aircraft) with vertical air motion from dual-Doppler wind synthesis (UAH). The cellular evolution starts with a warm rain phase where updrafts and a very low concentration of large drops dominate the cloud. As the supercooled drops rise in the updraft they freeze and acquire a water-coat possibly by collisions with other liquid drops. The multi-parameter radar signatures clearly identify this mixed-phase zone. The cloud thereafter gets electrified which may intensify to produce lightning depending on cloud vertical growth, and generation of updraft/ downdrafts.

  18. Radar-based dynamic testing of the cable-suspended bridge crossing the Ebro River at Amposta, Spain

    Energy Technology Data Exchange (ETDEWEB)

    Gentile, Carmelo [Politecnico di Milano, Dept. of Architecture, Built environment and Construction engineering (ABC), Piazza Leonardo da Vinci 32, 20133 Milan (Italy); Luzi, Guido [Centre Tecnòlogic de Telecomunicacions de Catalunya (CTTC), Division of Geomatics, Av. Gauss, 7 E-08860 Castelldefels (Barcelona) (Spain)

    2014-05-27

    Microwave remote sensing is the most recent experimental methodology suitable to the non-contact measurement of deflections on large structures, in static or dynamic conditions. After a brief description of the radar measurement system, the paper addresses the application of microwave remote sensing to ambient vibration testing of a cable-suspended bridge. The investigated bridge crosses the Ebro River at Amposta, Spain and consists of two steel stiffening trusses and a series of equally spaced steel floor beams; the main span is supported by inclined stay cables and two series of 8 suspension cables. The dynamic tests were performed in operational conditions, with the sensor being placed in two different positions so that the response of both the steel deck and the arrays of suspension elements was measured. The experimental investigation confirms the simplicity of use of the radar and the accuracy of the results provided by the microwave remote sensing as well as the issues often met in the clear localization of measurement points.

  19. Pedestrian recognition using automotive radar sensors

    Science.gov (United States)

    Bartsch, A.; Fitzek, F.; Rasshofer, R. H.

    2012-09-01

    The application of modern series production automotive radar sensors to pedestrian recognition is an important topic in research on future driver assistance systems. The aim of this paper is to understand the potential and limits of such sensors in pedestrian recognition. This knowledge could be used to develop next generation radar sensors with improved pedestrian recognition capabilities. A new raw radar data signal processing algorithm is proposed that allows deep insights into the object classification process. The impact of raw radar data properties can be directly observed in every layer of the classification system by avoiding machine learning and tracking. This gives information on the limiting factors of raw radar data in terms of classification decision making. To accomplish the very challenging distinction between pedestrians and static objects, five significant and stable object features from the spatial distribution and Doppler information are found. Experimental results with data from a 77 GHz automotive radar sensor show that over 95% of pedestrians can be classified correctly under optimal conditions, which is compareable to modern machine learning systems. The impact of the pedestrian's direction of movement, occlusion, antenna beam elevation angle, linear vehicle movement, and other factors are investigated and discussed. The results show that under real life conditions, radar only based pedestrian recognition is limited due to insufficient Doppler frequency and spatial resolution as well as antenna side lobe effects.

  20. Model-Based Estimation of Forest Canopy Height in Red and Austrian Pine Stands Using Shuttle Radar Topography Mission and Ancillary Data: a Proof-of-Concept Study

    Energy Technology Data Exchange (ETDEWEB)

    Brown Jr., C G; Sarabandi, K; Pierce, L E

    2007-04-06

    In this paper, accurate tree stand height retrieval is demonstrated using C-band Shuttle Radar Topography Mission (SRTM) height and ancillary data. The tree height retrieval algorithm is based on modeling uniform tree stands with a single layer of randomly oriented vegetation particles. For such scattering media, the scattering phase center height, as measured by SRTM, is a function of tree height, incidence angle, and the extinction coefficient of the medium. The extinction coefficient for uniform tree stands is calculated as a function of tree height and density using allometric equations and a fractal tree model. The accuracy of the proposed algorithm is demonstrated using SRTM and TOPSAR data for 15 red pine and Austrian pine stands (TOPSAR is an airborne interferometric synthetic aperture radar). The algorithm yields root-mean-square (rms) errors of 2.5-3.6 m, which is a substantial improvement over the 6.8-8.3-m rms errors from the raw SRTM minus National Elevation Dataset Heights.

  1. Research on CLIPS-based Fault Diagnosis Expert System of Radar%基于CLIPS的雷达故障诊断专家系统研究

    Institute of Scientific and Technical Information of China (English)

    吴立蓉; 王仁波

    2014-01-01

    The problem about radar maintenance in army mostly relies on the factory’s support. The timeliness and ef-fectiveness cannot satisfy the need of force. The design uses the artificial intelligence technology for building the fault di-agnosis Expert System based on CLIPS, make the general maintenance personnel could use and master the diagnosis tech-nology. That has great practical significance for improving the integrated supporting capability and increasing battle effec-tiveness of radar .%基层部队雷达维护保养,大部分是依靠工厂支援,及时性和有效性都不能满足部队需要。本设计利用人工智能技术来建造基于CLIPS故障诊断专家系统,使诊断技术为一般的维护人员所掌握和使用,这对提高该雷达综合保障力,促进其战斗力的形成都具有重大的现实意义。

  2. Three-dimensional interferometric inverse synthetic aperture radar imaging of maneuvering target based on the joint cross modified Wigner-Ville distribution

    Science.gov (United States)

    Lv, Qian; Su, Tao; Zheng, Jibin; Zhang, Jiancheng

    2016-01-01

    Inverse synthetic aperture radar (ISAR) can achieve high-resolution two-dimensional images of maneuvering targets. However, due to the indeterminate relative motion between radar and target, ISAR imaging does not provide the three-dimensional (3-D) position information of a target and suffers from great difficulty in target recognition. To tackle this issue, a 3-D interferometric ISAR (InISAR) imaging algorithm based on the joint cross modified Wigner-Ville distribution (MWVD) is presented to form 3-D images of maneuvering targets. First, we form two orthogonal interferometric baselines with three receiving antennas to establish an InISAR imaging system. Second, after the uniform range alignment and phase adjustment, the joint cross MWVD is used for all range cell of each antenna pair to generate the separation of the scatterer as well as preserve the phase that contains position information of the scatterer. At last, the 3-D images of the target can be directly reconstructed from the distribution. Simulation results demonstrate the validity of the proposal.

  3. Impacto de baixa velocidade em estruturas sandwich à base de cortiça

    OpenAIRE

    Nunes, Cláudia Patrícia Zeferino

    2009-01-01

    Os componentes tipo sandwich têm alcançado uma vasta aceitação em aplicações estruturais, devido às suas vantagens relativamente a outros materiais em termos de melhoria de estabilidade, elevada rigidez e resistência específicas. Os compósitos à base de aglomerados de cortiça apresentam-se como uma das alternativas mais promissoras aos materiais sintéticos para a construção de estruturas sandwich. Além das suas características estruturais únicas que permitem, entre outros aspectos, uma melhor...

  4. A grid-based distributed flood forecasting model for use with weather radar data: Part 2. Case studies

    Science.gov (United States)

    Bell, V. A.; Moore, R. J.

    A simple distributed rainfall-runoff model, configured on a square grid to make best use of weather radar data, was developed in Part 1 (Bell and Moore, 1998). The simple form of the basic model, referred to as the Simple Grid Model or SGM, allows a number of model variants to be introduced, including probability-distributed storage and topographic index representations of runoff production and formulations which use soil survey and land use data. These models are evaluated here on three catchments in the UK: the Rhondda in south Wales, the Wyre in north-west England and the Mole in the Thames Basin near London. Assessment is initially carried out in simulation mode to focus on the conversion of rainfall to runoff as influenced by (i) use of radar or raingauge input, (ii) choice of model variant, and (iii) use of a lumped or distributed model formulation. Weather radar data, in grid square and catchment average form, and raingauge data are used as alternative estimates of rainfall input to the model. Results show that when radar data are of good quality, significant model improvement may be obtained by replacing data from a single raingauge by 2 km grid square radar data. The performance of the Simple Grid Model with optimised isochrones is only marginally improved through the use of different model variants and is generally preferred on account of its simplicity. A more traditional lumped rainfall-runoff model, the Probability-Distributed Moisture model or PDM, is used as a benchmark against which to assess the performance of the distributed models. This proves hard to better, although the distributed formulation of the Grid model proves more reliable for some storm and catchment combinations where spatial effects on runoff response are evident. Assessment is then carried out in updating mode to emulate a real-time forecasting environment. First, a state updating form of the Grid Model is developed and then assessed against an ARMA error-prediction technique. Both

  5. CARACTERIZAÇÃO MORFOLÓGICA DO DELTA DO RIO DOCE (ES COM BASE EM ANÁLISE MULTISSENSOR

    Directory of Open Access Journals (Sweden)

    Silvia Palotti Polizel

    2014-08-01

    Full Text Available A costa leste brasileira apresenta uma sucessão de sistemas deltaicos, sendo o delta do rio Doce, localizado no Estado do Espírito Santo, um dos mais expressivos. A progradação principal deste delta, de geometria cuspidada típica de deltas de onda, tem sido atribuída à queda do nível do mar que se seguiu à transgressão holocênica média. Análises preliminares de novos produtos de sensoriamento remoto disponibilizados nesses últimos anos mostraram o potencial de aprimoramento do mapa geomorfológico desse delta, que pode contribuir para a melhor reconstituição paleoambiental e evolução desse sistema deposicional. Assim, este trabalho teve por objetivo fornecer um mapa geomorfológico detalhado para a planície costeira do rio Doce com base em dados multissensores integrando Modelo Digital de Elevação (MDE do Shuttle Radar Topography Mission (SRTM, Phased Array type L-band Synthetic Aperture Radar (PALSAR do Advanced Land Observing Satellite (ALOS, imagens TM/Landsat, além de imagens óticas de alta resolução extraídas do Google EarthTM. O mapeamento geomorfológico feito por interpretação visual resultou no estabelecimento de seis classes principais, designadas de: 1 drenagem atual; 2 cordão litorâneo/spit; 3 paleocanal; 4 planície interdistributária; 5 flúvio-estuarino/lagunar/marinho raso; e 6 terraço fluvial. De maneira geral, o emprego combinado dos produtos de sensoriamento produziu resultados satisfatórios para a separação dessas classes. O MDE-SRTM contribuiu para a identificação somente da classe paleocanais. As imagens PALSAR foram úteis na identificação das classes cordão litorâneo/spit, paleocanal, flúvio-estuarino/lagunar/marinho raso e terraço fluvial. As imagens TM/Landsat possibilitaram o reconhecimento das classes drenagem atual, cordão litorâneo/spit, planície interdistributária e flúvio-estuarino/lagunar/marinho raso. O mapa geomorfológico contribuiu na caracterização mais

  6. Tomographic Techniques for Radar Ice Sounding

    DEFF Research Database (Denmark)

    Nielsen, Ulrik

    AbstractLow frequency radars, also known as sounders, can be used for subsurfacemeasurements of Earth’s massive ice sheets. Radar data are essential toimproving ice sheet models for better prediction of the response of theseice sheets to global climate change. While airborne sounders are neededfor...... challenge. This dissertation deals with tomographic techniques based on multiphase-center radars that represent state-of-the-art technology within thefield of ice sounding. The use of advanced tomographic processing forclutter suppression is investigated, which up to this point has beenlargely unexplored...... acquired withthe POLarimetric Airborne Radar Ice Sounder (POLARIS), single-passtomographic surface clutter suppression capabilities are demonstratedfor the system. Using repeat-pass POLARIS data, a method based ondata-driven DOA estimation is used to show an along-track variation ofthe effective scattering...

  7. Radar Subsurface Imaging by Phase Shift Migration Algorithm

    OpenAIRE

    Zhang, Hui; Benedix, Wolf-Stefan; Plettemeier, Dirk; Ciarletti, Valérie

    2013-01-01

    In this paper the phase shift migration based Syn- thetic Aperture Radar (SAR) is described and applied on radar imaging for dual polarized ground penetrating radar system (GPR). Conventional techniques for SAR imaging focusing use the matched filter concept and convolve the measurement data with a filter impulse response (convolution kernel) which is modified by the range. In fact, conventional techniques for SAR imaging technique can be considered as ray-tracing based SAR imaging technique....

  8. Radar reconnaissance of near-Earth asteroids

    Science.gov (United States)

    Ostro, Steven J.; Giorgini, Jon D.; Benner, Lance A. M.

    2007-05-01

    Radar is a uniquely powerful source of information about near-Earth asteroid (NEA) physical properties and orbits. Measurements of the distribution of echo power in time delay (range) and Doppler frequency (radial velocity) constitute two-dimensional images that can provide spatial resolution finer than a decameter. The best radar images reveal geologic details, including craters and blocks. Radar wavelengths (13 cm at Arecibo, 3.5 cm at Goldstone) are sensitive to the bulk density (a joint function of mineralogy and porosity) and the degree of decimeter-scale structural complexity of the uppermost meter or so of the surface. Radar can determine the masses of binary NEAs via Kepler's third law and of solitary NEAs via measurement of the Yarkovsky acceleration. With adequate orientational coverage, a sequence of images can be used to construct a three-dimensional model, to define the rotation state, to determine the distribution of radar surface properties, and to constrain the internal density distribution. As of mid 2006, radar has detected echoes from 193 NEAs, of which 107 are designated Potentially Hazardous Asteroids. Radar has revealed both stony and metallic objects, principal-axis and non-principal-axis rotators, smooth and extremely rough surfaces, objects that appear to be monolithic fragments and objects likely to be nearly strengthless gravitational aggregates, spheroids and highly elongated shapes, contact-binary shapes, and binary systems. Radar can add centuries to the interval over which close Earth approaches can accurately be predicted, significantly refining collision probability estimates compared to those based on optical astrometry alone. If a small body is on course for a collision with Earth in this century, delay-Doppler radar echoes could almost immediately let us recognize this by distinguishing between an impact trajectory and a near miss, and would dramatically reduce the difficulty and cost of any effort to prevent the collision.

  9. Pigmentantes naturais em rações à base de sorgo para codornas japonesas em postura Natural pigments on sorghum-based rations for laying Japanese quails

    Directory of Open Access Journals (Sweden)

    Adolpho Marlon Antoniol de Moura

    2011-11-01

    Full Text Available Esta pesquisa foi realizada para avaliar os efeitos do uso de pigmentantes naturais e extratos de marigold e páprica em rações à base de sorgo para codornas japonesas. Foram utilizadas 180 codornas japonesas (Coturnix japonica, com 98 dias de idade, distribuídas em delineamento inteiramente casualizado em esquema de parcelas subdivididas, composto por cinco tratamentos e seis repetições com seis aves cada. O experimento foi dividido em seis períodos de quatro dias, totalizando 24 dias. Foram analisados o desempenho produtivo e a qualidade dos ovos das codornas. A cor da gema foi avaliada a cada quatro dias durante 24 dias pelo método do escore colorimétrico DSM. Não houve efeito dos tratamentos sobre o desempenho e a qualidade dos ovos das codornas, à exceção da cor da gema. O extrato de marigold proporcionou escore colorimétrico da gema equivalente ao das aves alimentadas com milho. A suplementação associada dos extratos de marigold e páprica proporcionou maior escore colorimétrico e em menor tempo. A utilização de pigmentantes naturais deve ser analisada considerando o escore colorimétrico que se deseja obter e o custo da suplementação de cada fonte comercial.The objective was to evaluate the effects of natural pigments from marigold extract and paprika to Japanese quails fed sorghum-based diets. One hundred and eight Japanese quails (Coturnix japonica, with 98 days of age were distributed in a complete randomized design in a split plot arrangement, with five treatments and six replicates of six birds each. The experiment was divided into six periods of four days each, totaling 24 days. Parameters productive performance and quail egg quality were evaluated. Yolk color was evaluated every 4 days for 24 days by the DSM colorimetric score method. There was no effect of experimental diets on performance or quality of quail egg, except for egg yolk color. The extract of marigold promoted yolk color scores equivalent to those

  10. Aspects of Radar Polarimetry

    OpenAIRE

    Lüneburg, Ernst

    2002-01-01

    This contribution is a tutorial introduction to the phenomenological theory of radar polarimetry for the coherent scatter case emphasizing monostatic backscattering and forward scattering (transmission). Characteristic similarities and differences between radar polarimetry and optical polarimetry and the role of linear and antilinear operators (time-reversal) are pointed out and typical polarimetric invariants are identified.

  11. Determination of radar MTF

    Energy Technology Data Exchange (ETDEWEB)

    Chambers, D. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    The ultimate goal of the Current Meter Array (CMA) is to be able to compare the current patterns detected with the array with radar images of the water surface. The internal wave current patterns modulate the waves on the water surface giving a detectable modulation of the radar cross-section (RCS). The function relating the RCS modulations to the current patterns is the Modulation Transfer Function (MTF). By comparing radar images directly with co-located CMA measurements the MTF can be determined. In this talk radar images and CMA measurements from a recent experiment at Loch Linnhe, Scotland, will be used to make the first direct determination of MTF for an X and S band radar at low grazing angles. The technical problems associated with comparing radar images to CMA data will be explained and the solution method discussed. The results suggest the both current and strain rate contribute equally to the radar modulation for X band. For S band, the strain rate contributes more than the current. The magnitude of the MTF and the RCS modulations are consistent with previous estimates when the wind is blowing perpendicular to the radar look direction.

  12. Java Radar Analysis Tool

    Science.gov (United States)

    Zaczek, Mariusz P.

    2005-01-01

    Java Radar Analysis Tool (JRAT) is a computer program for analyzing two-dimensional (2D) scatter plots derived from radar returns showing pieces of the disintegrating Space Shuttle Columbia. JRAT can also be applied to similar plots representing radar returns showing aviation accidents, and to scatter plots in general. The 2D scatter plots include overhead map views and side altitude views. The superposition of points in these views makes searching difficult. JRAT enables three-dimensional (3D) viewing: by use of a mouse and keyboard, the user can rotate to any desired viewing angle. The 3D view can include overlaid trajectories and search footprints to enhance situational awareness in searching for pieces. JRAT also enables playback: time-tagged radar-return data can be displayed in time order and an animated 3D model can be moved through the scene to show the locations of the Columbia (or other vehicle) at the times of the corresponding radar events. The combination of overlays and playback enables the user to correlate a radar return with a position of the vehicle to determine whether the return is valid. JRAT can optionally filter single radar returns, enabling the user to selectively hide or highlight a desired radar return.

  13. Research on Registration Methods Based on SRUKF between 3D Radar and 2D Radar%基于SRUKF的3D雷达与2D雷达的误差配准方法

    Institute of Scientific and Technical Information of China (English)

    刘德浩; 王国宏; 陈垒; 关成斌

    2012-01-01

    系统误差配准技术是雷达组网数据处理系统中必不可少的基础和关键技术,其目的是准确估计及消除组网雷达的系统误差.采用ECEF坐标系作为公共参考坐标系,推导了使用3D雷达配准2D雷达的3种方法,并采用均方根不敏卡尔曼滤波(SRUKF)对组网雷达系统误差进行实时估计.仿真结果表明,该算法可以有效地实现3D雷达与2D雷达之间距离和方位角的系统误差配准.%Registration is a necessary and prerequisite process for the data fusion in radar networking system to estimate and correct systematic errors accurately. Earth-centered-Earth-fixed (ECEF ) coordinates are taken as the common reference coordinates, three registration methods between 3D radar and 2D radar are deduced. SRUKF (Square Root Unscented Kalman Filter) is used to estimate the systematic errors. The result indicates that the algorithm could fulfill registration of slant and azimuth between 3D and 2D radars effectively.

  14. Micropower impulse radar imaging

    Energy Technology Data Exchange (ETDEWEB)

    Hall, M.S.

    1995-11-01

    From designs developed at the Lawrence Livermore National Laboratory (LLNL) in radar and imaging technologies, there exists the potential for a variety of applications in both public and private sectors. Presently tests are being conducted for the detection of buried mines and the analysis of civil structures. These new systems use a patented ultra-wide band (impulse) radar technology known as Micropower Impulse Radar (GPR) imaging systems. LLNL has also developed signal processing software capable of producing 2-D and 3-D images of objects embedded in materials such as soil, wood and concrete. My assignment while at LLNL has focused on the testing of different radar configurations and applications, as well as assisting in the creation of computer algorithms which enable the radar to scan target areas of different geometeries.

  15. <em>Pseudo-nitzschia seriataem> f. <em>obtusa> (Bacillariophyceae) raised in rank based onmorphological, phylogenetic and distributional data

    DEFF Research Database (Denmark)

    Hasle, Grethe Rytter; Lundholm, N.

    2005-01-01

    Pseudo-nitzschia seriata f. obtusa (Hasle) Hasle is raised in rank to P. obtusa (Hasle) Hasle & Lundholm, based on morphological, phylogenetic and distributional features. The most prominent distinctive morphological feature is the shape of the valve ends, which in girdle view are truncate in P...

  16. Wall Clutter Mitigation in Through-the-Wall Imaging Radar with Sparse Array Antenna Based on Independent Component Analysis

    Directory of Open Access Journals (Sweden)

    Zhang Chi

    2014-10-01

    Full Text Available For Through-the-Wall Imaging Radar (TWIR, wall clutter is critical for detecting target signals behind a wall. For a system with a sparse antenna array, the lack of observation channels makes it more difficult to separate the target signals and wall clutter. On the basis of fluctuation of the range profile in real transmit/receive channels, this paper proposes to use Independent Component Analysis (ICA on multiple down-range observations of each transmit/receive channel to remove the wall clutter. The simulation and experimental results show that the proposed method effectively separate target and clutter components, even though the signal-to-clutter ratio is only -30 dB.

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

    Science.gov (United States)

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

    2016-05-01

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

  18. Principles of modern radar radar applications

    CERN Document Server

    Scheer, James A

    2013-01-01

    Principles of Modern Radar: Radar Applications is the third of the three-volume seriesof what was originally designed to be accomplished in one volume. As the final volumeof the set, it finishes the original vision of a complete yet bounded reference for radartechnology. This volume describes fifteen different system applications or class ofapplications in more detail than can be found in Volumes I or II.As different as the applications described, there is a difference in how these topicsare treated by the authors. Whereas in Volumes I and II there is strict adherence tochapter format and leve

  19. IONOTOMO: A new approach for ionospheric tomography using OTH radar

    Science.gov (United States)

    Roy, Corinna; Occhipinti, Giovanni; Boschi, Lapo; Moliné, Jean-Philippe

    2013-04-01

    Most of the recent methods in ionospheric tomography are based on the inversion of the Total Electron Content (TEC) measured by ground-based GPS receivers [e.g., Garcia et al. 2008]. As a consequence of the high frequency of the GPS, the electron density structure is principally well reconstructed at the F2 region, where the ionosphere reaches the maximum of ionization, neglecting the lower ionosphere. Here, we develop a new 3D ionospheric tomography method based on the full analysis of over-the-horizon (OTH) radar data. Previous studies in ionospheric tomography by OTH radar (Fridman and Fridman, 1994; Ruelle and Landeau, 1994; Landeau et al., 1997; Fridman, 1998) are all based on the inversion of the leading edge echo curve, consequently an important amount of valuable information present in the data is necessarily neglected. To overcome this limit, we set up a new method, based on the ray-tracing tool TDR [Occhipinti, 2006], to invert the propagation time of electromagnetic waves emitted by monostatic OTH radars. The major advance of our methodology is taking into account, numerically and jointly, not only the speed variation of EM wave induced by the electron density variation (solved analytically with a linear inversion) but also the perturbation in the raypath (nonlinear numerical method). As the present problem is an ill posed problem we calculate the matrix inversion numerically, using a regularisation method (Tikhonov, 1963). We determine the best regularisation parameter using the Lcurve method (Hansen, 2000). We present here the originality and the advantage of our method with a full set of synthetic benchmark highlighting the sensitivity of our tomography to the plasma heterogeneities. Some preliminary test on real data will be presented with a full coverage over Europe. Indeed, the ionospheric tomography by OTH radar, jointly with GPS, could open new exciting perspective in the plasma density estimation with a good resolution to the entire ionosphere

  20. Method of Monitoring Radar Running State Based on Mobile Phone Mailbox%基于手机邮箱监控天气雷达运行状态的方法

    Institute of Scientific and Technical Information of China (English)

    吴少峰; 罗森波; 胡东明; 张羽

    2012-01-01

    Based on China mobile E-mail monitor the radar station, was introduced, the basis of comparison of advantages and more methods could be used for other radar business, a new message-alarm method, which could also and the principle of the method was described in detail. On disadvantages between these two methods, it is hoped that stations in designing radar state monitoring system.%介绍了一种新的短信报警方法,通过巧妙应用中国移动的139邮箱业务,同样能完成对雷达状态的监控,并详细阐述了该方法的原理,最后对两种方法的优劣势进行了对比分析,为台站在设计监控软件时能有多种选择。

  1. Prevalência de transtornos ansiosos e algumas comorbidades em idosos: um estudo de base populacional

    Directory of Open Access Journals (Sweden)

    Mayara B. Machado

    2016-03-01

    Full Text Available RESUMO Objetivo Avaliar a prevalência de transtornos ansiosos e fatores associados em uma amostra populacional de idosos do Sul de Santa Catarina. Métodos Estudo transversal com base em dados populacionais, que avaliou 1.021 indivíduos idosos entre 60 e 79 anos. Foram realizadas entrevistas domiciliares para aferição de variáveis sobre transtornos ansiosos, por meio do questionário MINI, dados sociodemográficos, hipertensão arterial sistêmica (HAS, infarto agudo do miocárdio (IAM e dosagem de colesterol. Resultados As prevalências entre os transtornos ansiosos foram de 22,0% para o transtorno de ansiedade generalizada (TAG; 14,8% para fobia social (FS; 10,5% para transtorno do pânico (TP; e 8,5% para o transtorno obsessivo-compulsivo (TOC. Além disso, 40,5% dos indivíduos apresentaram pelo menos um transtorno de ansiedade. A distribuição dos transtornos foi semelhante nos dois gêneros; TAG foi mais prevalente nos indivíduos de menor escolaridade; TOC foi mais presente em indivíduos casados ou em união estável. Em relação às variáveis clínicas, HAS foi associada à presença de TOC; FS foi associada com IAM; TOC e FS foram associados com HDL > 40 mg/dL. Conclusão Os dados demonstram que os quadros de ansiedade são muito frequentes em idosos da comunidade, se sobrepõem de forma significativa e estão associados a algumas variáveis clínicas cardiovasculares.

  2. Advanced Spacecraft EM Modelling Based on Geometric Simplification Process and Multi-Methods Simulation

    Science.gov (United States)

    Leman, Samuel; Hoeppe, Frederic

    2016-05-01

    This paper is about the first results of a new generation of ElectroMagnetic (EM) methodology applied to spacecraft systems modelling in the low frequency range (system's dimensions are of the same order of magnitude as the wavelength).This innovative approach aims at implementing appropriate simplifications of the real system based on the identification of the dominant electrical and geometrical parameters driving the global EM behaviour. One rigorous but expensive simulation is performed to quantify the error generated by the use of simpler multi-models. If both the speed up of the simulation time and the quality of the EM response are satisfied, uncertainty simulation could be performed based on the simple models library implementing in a flexible and robust Kron's network formalism.This methodology is expected to open up new perspectives concerning fast parametric analysis, and deep understanding of systems behaviour. It will ensure the identification of main radiated and conducted coupling paths and the sensitive EM parameters in order to optimize the protections and to control the disturbance sources in spacecraft design phases.

  3. SuperDARN scalar radar equations

    CERN Document Server

    Berngardt, O I; Potekhin, A P

    2016-01-01

    The quadratic scalar radar equations are obtained for SuperDARN radars that are suitable for the analysis and interpretation of experimental data. The paper is based on a unified approach to the obtaining radar equations for the monostatic and bistatic sounding with use of hamiltonian optics and ray representation of scalar Green's function and without taking into account the polarization effects. The radar equation obtained is the sum of several terms corresponding to the propagation and scattering over the different kinds of trajectories, depending on their smoothness and the possibility of reflection from the ionosphere. It is shown that the monostatic sounding in the media with significant refraction, unlike the case of refraction-free media, should be analyzed as a combination of monostatic and bistatic scattering. This leads to strong dependence of scattering amplitude on background ionospheric density due to focusing mechanism and appearance of new (bistatic) areas of effective scattering with signific...

  4. Radar Surface Target Echo Simulation Technology Based on Wideband DRFM%基于宽带DRFM的雷达面目标回波模拟技术

    Institute of Scientific and Technical Information of China (English)

    肖汉波; 张长青

    2015-01-01

    针对跳频雷达高度表大地面目标回波信号的模拟,提出了一种基于宽带数字射频存储(DRFM)技术的实现方案。首先介绍了1.2 GHz带宽、3 GHz采样的宽带DRFM组件硬件平台,然后重点叙述了基于DRFM技术的雷达高度表大地面目标回波模拟的算法设计方案,通过采用多路并行处理、多相滤波、正交调制等技术实现了数字下变频、目标回波特征调制、数字上变频等关键算法,最后给出了算法仿真和硬件调试结果,验证了算法的正确性和有效性。该方案已成功应用到某宽带跳频雷达高度表大地面目标回波模拟系统的设计中。%For the simulation of frequency hopping( FH) radar altimeter’s echo signal of ground surface,an implemented solution based on wideband Digital Radio Frequency Memory( DRFM) is presented. First,the DRFM hardware platform with the bandwidth of 1 . 2 GHz and the sampling rate of 3 GHz is briefly intro-duced. Second,the design of algorithm for the simulation of radar altimeter’s echo signal of ground surface based on DRFM is focused on,and digital down conversion,modulation for the echo signal’s characteris-tics,digital up conversion are implemented by multi-channel parallel processing,poly-phased filtering and orthogonal modulation. Finally, the algorithmic simulation and the results of hardware debugging are shown,which verifies the correctness and validity of the algorithm. This solution has been utilized in the design of the system of wideband FH radar altimeter’s echo signal of ground surface.

  5. Alpine radar conversion for LAWR

    Science.gov (United States)

    Savina, M.; Burlando, P.

    2012-04-01

    The Local Area Weather Radar (LAWR) is a ship-born weather radar system operating in X-band developed by the DHI Group to detect precipitation in urban areas. To date more than thirty units are installed in different settings around the world. A LAWR was also deployed in the Alps, at 3883 m a.s.l. on the Kl. Matterhorn (Valais, Switzerland). This was the highest LAWR of the world and it led to the development of an Alpine LAWR system that, besides featuring important technological improvements needed to withstand the severe Alpine conditions, required the development of a new Alpine Radar COnversion Model (ARCOM), which is the main focus of this contribution. The LAWR system is equipped with the original FURUNO fan-beam slotted antenna and the original logarithmic receiver, which limits the radar observations to the video signal (L) withour providing the reflectivity (Z). The beam is 0.95 deg wide and 20 deg high. It can detect precipitation to a max range of 60 km. In order to account for the limited availability of raw signal and information and the specific mountain set-up, the conversion model had to be developed differently from the state-of-the-art radar conversion technique used for this class of radars. In particular, the ARCOM is based on a model used to simulate a spatial dependent factor, hereafter called ACF, which is in turn function of parameters that take in account climatological conditions, also used in other conversion methods, but additionally accounting for local radar beam features and for orographic forcings such as the effective sampling power (sP), which is modelled by means of antenna pattern, geometric ground clutter and their interaction. The result is a conversion factor formulated to account for a range correction that is based on the increase of the sampling volume, partial beam blocking and local climatological conditions. The importance of the latter in this study is double with respect to the standard conversion technique for this

  6. Weather radar rainfall data in urban hydrology

    Science.gov (United States)

    Thorndahl, Søren; Einfalt, Thomas; Willems, Patrick; Ellerbæk Nielsen, Jesper; ten Veldhuis, Marie-Claire; Arnbjerg-Nielsen, Karsten; Rasmussen, Michael R.; Molnar, Peter

    2017-03-01

    Application of weather radar data in urban hydrological applications has evolved significantly during the past decade as an alternative to traditional rainfall observations with rain gauges. Advances in radar hardware, data processing, numerical models, and emerging fields within urban hydrology necessitate an updated review of the state of the art in such radar rainfall data and applications. Three key areas with significant advances over the past decade have been identified: (1) temporal and spatial resolution of rainfall data required for different types of hydrological applications, (2) rainfall estimation, radar data adjustment and data quality, and (3) nowcasting of radar rainfall and real-time applications. Based on these three fields of research, the paper provides recommendations based on an updated overview of shortcomings, gains, and novel developments in relation to urban hydrological applications. The paper also reviews how the focus in urban hydrology research has shifted over the last decade to fields such as climate change impacts, resilience of urban areas to hydrological extremes, and online prediction/warning systems. It is discussed how radar rainfall data can add value to the aforementioned emerging fields in current and future applications, but also to the analysis of integrated water systems.

  7. Radar-based observatiions of variable thickness debris cover on martian ice masses: evidence of debris transfer by flowing ice on Mars

    Science.gov (United States)

    Souness, Colin; Brough, Stephen; Woodward, John; Hubbard, Bryn; Davis, Joel; Grindrod, Peter

    2016-04-01

    The mid-latitudes of Mars host a wide range of ice-based landforms, many of which display surface morphologies indicative of viscous flow of that ice. Despite being shrouded beneath a layer of rocky debris, these viscous flow features (VFFs) are thought to have similarities with terrestrial glaciers. Until recently most studies that focussed on the origin, structure and role of these martian VFFs were restricted to observations made from satellite imagery. Little data have been available to gain a clearer picture of VFF internal structure, which has impeded our collective ability to infer many particulars of VFF growth and flow, including the extent to which these ice flows have interacted with, and potentially helped shape, the martian landscape. However, the Shallow Radar (SHARAD) system mounted on the Mars Reconnaissance Orbiter (MRO) can, in some cases, provide a valuable insight into what lies beneath the surface of these ice masses. We present a SHARAD-based study of glacial systems on Mars which reveals pronounced heterogeneity in the thickness of their observed superficial debris covers. The surface debris layers in question appear to thicken in a down-slope direction. Radar data indicates that in the lower reaches of each studied glacial catchment, ice surface debris cover exceeds 10 m in thickness. The observed flow-parallel a-symmetry in debris thickness atop these martian glaciers is similar to that recorded on many terrestrial glaciers, indicating that cumulative down-flow debris mass transfer such as occurs within glacierised catchments on Earth may also currently operate, or have operated, on Mars. This suggests that glaciers on Mars have played a substantial role in redistributing lithic material from mountainous catchments to lower-lying areas, potentially throughout the glacial regions of Mars' mid-latitudes, thus making an important processual contribution to the evolution of Mars' contemporary landscape.

  8. Texture-based seismic damage assessment on radar data: a preliminary comparison between COSMO/SkyMed and TerraSAR-X datasets

    Science.gov (United States)

    Harb, Mostapha; Dell'Acqua, Fabio

    2013-04-01

    This study focuses on remote sensing technology as a disaster monitoring tool. It emphasizes on Synthetic-aperture radar (SAR) applications to extract geo-information relevant to damage assessment on the block level from single post disaster imagery. The procedure undertaken was previously developed by our group, based on discovered correlations between texture measures on radar images and the extent of seismic damage in any given urban block. Ground truthing was based on a "Damaged Area Ratio" (DAR) damage indicator, computed as the area ratio of the damaged buildings to the block area. The damaged buildings were detected using data from high-resolution airborne sensors, thus only high levels of damage, mainly with ceiling partial or complete collapse, were considered due to the limitation of the space borne technology in detecting slight to moderate damages as well as the sandwich damages. The urban areas in the studied cities were allocated into a number of blocks, where DAR was calculated for each block. After that, damage categorization was applied using thresholds on the DAR values of the selected blocks. This work continues the investigation on the linear correlation between the textural features and the calculated damage indicator DAR. For that purpose, data acquisitions were analysed from two different SAR satellite sensors, TerraSAR-X and COSMO/Sky-Med. As test cases, damages from two earthquakes were analysed with different geometric resolutions: L'Aquila 2009 using High Resolution Spotlight images and Haiti 2010 using Strip Map images. The data were analysed with similar techniques for the sake of an objective comparison on the variations on the linear correlations. The funding and support of the Italian Department of Civil Protection through the "Progetto Esecutivo 2012-13", as well as the support from the German Aerospace Agency through the LAN 1240 project are gratefully acknowledged.

  9. Train speed measurement system based on the scanning laser radar%基于扫描激光雷达的列车速度测量系统

    Institute of Scientific and Technical Information of China (English)

    刘常杰; 刘洪伟; 郭寅; 刘邈; 张宾; 叶声华

    2015-01-01

    Concerning the difficulties such as small measuring range and complicated operation in traditional train speed measure device, a new speed measuring system for dynamic clearance limit measurement of high-speed train is designed based on scanning laser radar. The scanning laser radar fixed in the position of 10 meters from the train. According to the principle of pulsed time-of-flight laser ranging, after the train enters the scan range the scanning laser radar scans the train point by point along the direction of train obtains the body contours. Process measurement data of cars with least square method to obtain the track and direction of the train. The travel distance of the train during two adjacent measurement cycle can be measured through piecewise linear interpolation. Complete the train speed measurement through the above work. Field experiments show that the system is easy to operate with capacity of 600 km/h and the system measurement error is less than 1.2% meets the demand of high-speed train velocity measurement.%针对传统列车速度测量装置存在量程小、调试复杂等问题,基于扫描激光雷达技术,设计了一套适用于高速列车动态限界测量的列车速度测量系统。将扫描激光雷达固定在距列车10 m左右的位置上,根据激光脉冲飞行时间测距原理,沿列车行驶方向对进入扫描范围内的列车车身逐点扫描,获得由测量点组成的车身轮廓信息;通过最小二乘拟合车厢测量点,得到列车行驶轨迹,确定列车行驶方向;采用分段线性差值确定相邻两次测量周期内列车行驶的距离,完成列车速度的测量。结果表明:该测速系统操作方便,量程可达600 km/h,测速误差控制在±1.2%以内,可以满足高速列车速度测量需求。

  10. SIRE: A MIMO Radar for Landmine/IED Detection

    Science.gov (United States)

    2013-04-30

    www.globalissues.org/article/79/ landmines (Nov. 2009). [2] Montoya, T. and Smith, G., “Land mine detection using a ground - penetrating radar based on...Park, NC 27709-2211 15. SUBJECT TERMS ground penetrating radar , image reconstruction, RFI Ode Ojowui Jr, Jian Li Howard University 2400 6th Street...used by these radars provide the necessary ground penetration capabilities for detection and the wide bandwidth signals used are necessary for range

  11. MIMO Radar Using Compressive Sampling

    CERN Document Server

    Yu, Yao; Poor, H Vincent

    2009-01-01

    A MIMO radar system is proposed for obtaining angle and Doppler information on potential targets. Transmitters and receivers are nodes of a small scale wireless network and are assumed to be randomly scattered on a disk. The transmit nodes transmit uncorrelated waveforms. Each receive node applies compressive sampling to the received signal to obtain a small number of samples, which the node subsequently forwards to a fusion center. Assuming that the targets are sparsely located in the angle- Doppler space, based on the samples forwarded by the receive nodes the fusion center formulates an l1-optimization problem, the solution of which yields target angle and Doppler information. The proposed approach achieves the superior resolution of MIMO radar with far fewer samples than required by other approaches. This implies power savings during the communication phase between the receive nodes and the fusion center. Performance in the presence of a jammer is analyzed for the case of slowly moving targets. Issues rel...

  12. Screening and Analysis of the Potential Bioactive Components in Rabbit Plasma after Oral Administration of Hot-Water Extracts from Leaves of <em>B>ambusa em>>textilis em>McClure

    Directory of Open Access Journals (Sweden)

    Jia Sun

    2012-07-01

    Full Text Available <em>Bambusa textilisem> McClure is a traditional Chinese medicinal plant belonging to the Bambusoideae subfamily and used to treat chronic fever and infectious diseases. To investigate the bioactive compounds absorbed in the rabbit blood after oral administration of hot-<em>water extractem>>s from em>>the leaves of em>>B. textilisem> McClure, a validated chromatographic fingerprint method was established using LC-Q-TOF-MS. Twenty compounds in bamboo leaves and three potential bioactive compounds in rabbit plasma were detected. Of the twenty detected compounds <em>in vitroem>, fifteen of which were tentatively identified either by comparing the retention time and mass spectrometry data with that of reference compounds or by reviewing the literature. Three potential bioactive compounds, including (<em>E-p>-coumaric acid, (<em>Z-p>-coumaric acid, and apigenin-8-<em>C>-β-D-(2"-<em>O>-α-L-rhamnosyl-gluco-pyranoside, were detected in both <em>the leaves of em>>B. textilis em>McClure and rabbit plasma. Of the three compounds, apigenin-8-<em>C>-β-D-(2"-<em>O>-α-L-rhamnosylglucopyranoside was identified based on its UV, MS, and NMR spectra. This study provides helpful chemical information for further pharmacology and active mechanism research on <em>B. textilisem> McClure.

  13. Variabilidade genética em batata-doce com base em marcadores isoenzimáticos

    Directory of Open Access Journals (Sweden)

    Oliveira Antonio Carlos B. de

    2002-01-01

    Full Text Available A variabilidade genética de 55 clones de batata-doce, compreendendo cultivares comerciais e acessos obtidos de coletas, foi avaliada por meio de padrões isoenzimáticos, utilizando-se técnicas de análise multivariada. Cultivou-se uma planta por vaso, com 2 litros de capacidade, preenchido com terra, esterco e areia lavada na proporção de 3:2:1, com três repetições. As coletas das folhas e raízes novas para análises iniciaram-se aos 45 dias após o plantio. Foram utilizados, para folhas, os sistemas enzimáticos: GOT, alfaEST, betaEST, PGI, PGM e IDH e, para as raízes: PRX, alfaEST, betaEST, PGI, PGM e IDH. A combinação dos diferentes padrões enzimáticos e tecidos analisados possibilitou a discriminação individual de 32 dos 55 clones analisados. Os 23 clones restantes foram incluídos em sete grupos distintos, com base nos fenótipos isoenzimáticos exibidos. Os clones, dentro de cada um desses grupos, foram considerados materiais de mesmo genótipo, devido, também, às suas características morfológicas semelhantes. A aEST de raízes foi o sistema que apresentou maior número de bandas polimórficas, proporcionando a discriminação individual de 32 clones. O método de agrupamento de Tocher reuniu os 39 clones em nove grupos e, a análise pelo método das médias das distâncias, revelou a formação de onze grupos de similaridade. O clone 46 formou um grupo individual pelo método de Tocher e foi o mais divergente pelo método das médias das distâncias. Por apresentar boas características comerciais e produtivas, seria um dos clones eleitos para se iniciar programas de cruzamentos.

  14. Radar cross section

    CERN Document Server

    Knott, Gene; Tuley, Michael

    2004-01-01

    This is the second edition of the first and foremost book on this subject for self-study, training, and course work. Radar cross section (RCS) is a comparison of two radar signal strengths. One is the strength of the radar beam sweeping over a target, the other is the strength of the reflected echo sensed by the receiver. This book shows how the RCS ?gauge? can be predicted for theoretical objects and how it can be measured for real targets. Predicting RCS is not easy, even for simple objects like spheres or cylinders, but this book explains the two ?exact? forms of theory so well that even a

  15. Radar and electronic navigation

    CERN Document Server

    Sonnenberg, G J

    2013-01-01

    Radar and Electronic Navigation, Sixth Edition discusses radar in marine navigation, underwater navigational aids, direction finding, the Decca navigator system, and the Omega system. The book also describes the Loran system for position fixing, the navy navigation satellite system, and the global positioning system (GPS). It reviews the principles, operation, presentations, specifications, and uses of radar. It also describes GPS, a real time position-fixing system in three dimensions (longitude, latitude, altitude), plus velocity information with Universal Time Coordinated (UTC). It is accur

  16. To See the Unseen: A History of Planetary Radar Astronomy

    Science.gov (United States)

    Butrica, Andrew J.

    1996-01-01

    This book relates the history of planetary radar astronomy from its origins in radar to the present day and secondarily to bring to light that history as a case of 'Big Equipment but not Big Science'. Chapter One sketches the emergence of radar astronomy as an ongoing scientific activity at Jodrell Bank, where radar research revealed that meteors were part of the solar system. The chief Big Science driving early radar astronomy experiments was ionospheric research. Chapter Two links the Cold War and the Space Race to the first radar experiments attempted on planetary targets, while recounting the initial achievements of planetary radar, namely, the refinement of the astronomical unit and the rotational rate and direction of Venus. Chapter Three discusses early attempts to organize radar astronomy and the efforts at MIT's Lincoln Laboratory, in conjunction with Harvard radio astronomers, to acquire antenna time unfettered by military priorities. Here, the chief Big Science influencing the development of planetary radar astronomy was radio astronomy. Chapter Four spotlights the evolution of planetary radar astronomy at the Jet Propulsion Laboratory, a NASA facility, at Cornell University's Arecibo Observatory, and at Jodrell Bank. A congeries of funding from the military, the National Science Foundation, and finally NASA marked that evolution, which culminated in planetary radar astronomy finding a single Big Science patron, NASA. Chapter Five analyzes planetary radar astronomy as a science using the theoretical framework provided by philosopher of science Thomas Kuhn. Chapter Six explores the shift in planetary radar astronomy beginning in the 1970s that resulted from its financial and institutional relationship with NASA Big Science. Chapter Seven addresses the Magellan mission and its relation to the evolution of planetary radar astronomy from a ground-based to a space-based activity. Chapters Eight and Nine discuss the research carried out at ground-based

  17. The Southern Argentine Agile Meteor Radar (SAAMER)

    Science.gov (United States)

    Janches, Diego

    2014-11-01

    The Southern Argentina Agile Meteor Radar (SAAMER) is a new generation system deployed in Rio Grande, Tierra del Fuego, Argentina (53 S) in May 2008. SAAMER transmits 10 times more power than regular meteor radars, and uses a newly developed transmitting array, which focuses power upward instead of the traditional single-antenna-all-sky configuration. The system is configured such that the transmitter array can also be utilized as a receiver. The new design greatly increases the sensitivity of the radar enabling the detection of large number of particles at low zenith angles. The more concentrated transmitted power enables additional meteor studies besides those typical of these systems based on the detection of specular reflections, such as routine detections of head echoes and non-specular trails, previously only possible with High Power and Large Aperture radars. In August 2010, SAAMER was upgraded to a system capable to determine meteoroid orbital parameters. This was achieved by adding two remote receiving stations approximately 10 km away from the main site in near perpendicular directions. The upgrade significantly expands the science that is achieved with this new radar enabling us to study the orbital properties of the interplanetary dust environment. Because of the unique geographical location, SAAMER allows for additional inter-hemispheric comparison with measurements from Canadian Meteor Orbit Radar, which is geographically conjugate. Initial surveys show, for example, that SAAMER observes a very strong contribution of the South Toroidal Sporadic meteor source, of which limited observational data is available. In addition, SAAMER offers similar unique capabilities for meteor showers and streams studies given the range of ecliptic latitudes that the system enables detailed study of showers at high southern latitudes (e.g July Phoenicids or Puppids complex). Finally, SAAMER is ideal for the deployment of complementary instrumentation in both, permanent

  18. Comparative study of <em>Gymnodinium mikimotoiem> and <em>Gymnodinium aureolum em>comb. nov. (= <em>Gyrodinium aureolumem>) based on morphology, pigment composition, and molecular data

    DEFF Research Database (Denmark)

    Hansen, Gert; Daugbjerg, Niels; Henriksen, Peter

    2000-01-01

    were nearly identical in all isolates, and molecular analyses using maximum likelihood, parsimony, and neighbor joining showed the geographical isolates as an unresolved clade. Based on the available data it is concluded that the European isolates, formerly identified as Gyrodinium aureolum, Gyrodinium...... cf. aureolum, or Gymnodinium cf. nagasakiense, are conspecific with the Japanese Gymnodinium mikimotoi. An isolate from the Pettaquamscutt River, USA, is suggested to represent what Hulburt (1957) described as Gyrodinium aureolum. The LSU rDNA sequence data and ultrastructural characters...

  19. Airborne Radar Interferometric Repeat-Pass Processing

    Science.gov (United States)

    Hensley, Scott; Michel, Thierry R.; Jones, Cathleen E.; Muellerschoen, Ronald J.; Chapman, Bruce D.; Fore, Alexander; Simard, Marc; Zebker, Howard A.

    2011-01-01

    Earth science research often requires crustal deformation measurements at a variety of time scales, from seconds to decades. Although satellites have been used for repeat-track interferometric (RTI) synthetic-aperture-radar (SAR) mapping for close to 20 years, RTI is much more difficult to implement from an airborne platform owing to the irregular trajectory of the aircraft compared with microwave imaging radar wavelengths. Two basic requirements for robust airborne repeat-pass radar interferometry include the ability to fly the platform to a desired trajectory within a narrow tube and the ability to have the radar beam pointed in a desired direction to a fraction of a beam width. Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) is equipped with a precision auto pilot developed by NASA Dryden that allows the platform, a Gulfstream III, to nominally fly within a 5 m diameter tube and with an electronically scanned antenna to position the radar beam to a fraction of a beam width based on INU (inertial navigation unit) attitude angle measurements.

  20. 基于MSCOMM的雷情实时处理软件的设计%Design of radar information real-time process software based on the MSCOMM

    Institute of Scientific and Technical Information of China (English)

    祁春; 毛小玲; 房瑾

    2015-01-01

    Facing to finite telemetry resources, The radar information is an effective way to meet the needs of ground real-time monitoring. The functional components and communication realization method base on MSCOMM was introduced. Some key technologies, like multithreading, data frames processing method and admixture programming with VC and Matlab were emphasized, which can not only improve the software performance but also can ease the programming burden, and shorten the period of developing. The software can analyze radar information correctly and meet the requirement of multiple planes real-time monitoring that relieve the need stress of telemetry resource.%面对日益紧张的遥测资源,雷情数据是解决资源紧张的一种有效实现途径。本文介绍了基于MSCOMM控件的雷情数据实时处理软件的功能组成及通信实现方法,并着重阐述了多线程及雷情数据帧接收与处理、VC与Matlab混合编程等关键技术,在提高软件运行性能的同时减轻了拟合及插值算法的编程负担,加快了软件研制进度。实际应用表明:雷情数据解析正确,满足多目标试飞实时监控任务要求,缓解了遥测资源压力。

  1. Control algorithm of radar simulation engine based on message driven%基于消息驱动的雷达仿真引擎控制算法

    Institute of Scientific and Technical Information of China (English)

    王磊; 陈明燕; 张伟; 卢显良

    2012-01-01

    The distributed simulation becomes a better solution for the large-scale complicated system, and the key technique is the design of the distributed engine mechanism. Firstly a radar simulation system model is expounded and then a distributed scheduling control structure based on message service center and runtime monitor center is proposed. This engine could detach higher user interface service from lower message passing service and enhance the flexibility and usability of radar simulation software. Under this mechanism, the message passing algorithm (MPA) is put forward. System experimental results demonstrate that the control structure and MPA are fit for both central structure and distributed structure, and also realize the interconnection and communication between logical processes.%分布式仿真可以很好地解决大规模复杂系统仿真困难等问题,其关键技术在于分布式引擎机制的设计.首先阐述雷达系统仿真模型,然后提出基于消息服务中心和运控中心的分布式调度控制结构,将上层用户接口和底层消息传递服务解耦,灵活性和易操作性更强.接着提出消息驱动控制算法(message passing algorithm,MPA).系统测试结果表明,引擎结构和MPA适用于集中式和分布式结构,可以实现进程间的消息传递控制.

  2. 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.

  3. On paleodrainage evolution in mid-late Epipleistocene based on radar remote sensing in northeastern Ejin Banner, Inner Mongolia

    Institute of Scientific and Technical Information of China (English)

    WANGXinyuan; GUOHuadong; CHANGYueming; ZHALiangsong

    2004-01-01

    Radar remote sensing can acquire information of sub-surface covered by sand in arid area,detect surface roughness and vegetation coronet's layer and linear feature such as linear structure and channel sensitively. With sediment facies analysis, this paper studies the features of environmental evolution in mid-late Epipleistocene (60 ka BP-20 ka BP) in northeastem Ejin Banner. The conclusions are listed as follows: (1) The evolution of the three lakes, i.e. Gaxunnur, Sugunur and Tian'e lakes, are dominated by faults and regional climate. (2) By analyzing sedimentary section of old Juyanze Lake,the three lakes used to be a large outflow lake before 50 ka BP in northeastem Ejin Banner, and at 50 ka BP, temperature declined rapidly in northwestem China. The event caused the lake's shrinkage. (3)By fault activity uplift in the northem part of old Juyan Lake and depression in the southem part, the lake's water followed fi'om north to south at around 35 ka BP, old Juyanze fluvial fan was formed. At the same time, Juyan lake separated fi'om Sugunur Lake and Wentugunr old channel was abandoned.(4) In recent 2000 years, Ruoshui River is a wandering river, sometimes it flows into Juyan lake and sometimes Sugunur and Gaxunnur lakes. Due to human activities and over exploitation, the oasis ecosystem is rapidly degenerated in 15 years (1986-2000).

  4. Base eletronica de dados clinicos e cirurgicos em isquemia cronica de membros inferiores

    Directory of Open Access Journals (Sweden)

    Carlos Seme Nejm Junior

    2013-09-01

    Full Text Available CONTEXTO: Um sistema eletrônico de protocolo seria capaz de armazenar dados clínicos e possibilitar futuras pesquisas, visando a rapidez, eficiência de cruzamentos e análise de tais dados. OBJETIVO: a criar uma base de dados clínicos cirúrgicos em doenças vasculares e, a partir desta, uma base em Isquemia Crônica de Membros Inferiores; b informatizar essa base sob forma de um protocolo eletrônico; c incorporar ao SINPE(c (Sistema Integrado de Protocolos Eletrônicos; d realizar um projeto piloto. MÉTODOS: Criou-se uma base teórica de dados clínicos sobre as doenças vasculares. O protocolo específico foi criado considerando-se as características individuais das doenças causadoras de Isquemia Crônica de Membros Inferiores. Após seu término, essa base eletrônica e informatizada seria incorporada ao SINPE(c. RESULTADOS: O usuário, previamente cadastrado, realizará o cadastro do paciente e selecionará, dentro do protocolo mestre, o protocolo específico em Isquemia Crônica de Membros Inferiores, para acesso aos seus respectivos dados clínicos. Orientado pelas alternativas diretas de preenchimento, o usuário seleciona apenas os dados pertencentes ao seu paciente. Estes podem ser resgatados para pesquisa, mostrando o número de coletas que satisfazem os parâmetros escolhidos e informações estatísticas sobre a mesma. CONCLUSÃO: a a criação da base teórica de dados clínicos e cirúrgicos em doenças vasculares e, a partir desta, em Isquemia Crônica de Membros Inferiores, foi factível; b a informatização da base teórica sob forma de protocolo eletrônico foi exequível; c o protocolo eletrônico mestre e específico poderá ser incorporado ao SINPE(c, d o projeto piloto foi criado com sucesso e testado através do módulo analisador do SINPE(c.

  5. 基于贝叶斯网络的某机载雷达电磁损伤评估%Electromagnetic Damage Assessment of Airborne Radar Based on Bayesian Networks

    Institute of Scientific and Technical Information of China (English)

    金焱; 胡云安; 张瑾; 黄隽

    2012-01-01

    Aiming at the problem that airborne radar is facing more and more serious threats by electromagnetic pulse (EMP) weapon, the research on electromagnetic damage assessment of airborne radar is carried out in this paper. By analyzing and simplifying the radar's structure, the Bayesian network model is established to assess the electromagnetic damage of the radar, and the network parameters could be determined on the basis of repair time demand. The radar repairing scheme could also be decided based on the expected efficiency of repair. Simulation results show that, under the conditions of 100 m distance, 10 GW power and EMP beam center aiming at the radar, the middle damaged degree of airborne radar is made by high power microwave bomb MK84. Its repairing order is given as well. The electromagnetic damage assessment method proposed in the paper is of military application values for repair and enhancement of the radar suffering electromagnetic attack.%针对机载雷达面临越来越严重的电磁脉冲武器威胁的现实问题,开展了机载雷达的电磁损伤评估.通过对雷达结构的分析和简化以及由抢修时间来确定网络参数的方法,建立了雷达电磁损伤评估的贝叶斯网络模型;利用贝叶斯网络推理评定雷达的电磁损伤等级;在定义了期望抢修效率的基础上给出雷达抢修决策的方法.仿真结果显示:在距离100m,辐射功率10GW,波束中心对准机载雷达的条件下,高功率微波弹MK84将对某机载雷达造成中等损伤,给出了该条件下雷达的抢修顺序.该方法对于开展机载雷达电磁损伤抢修和电磁加固具有一定的军事应用价值.

  6. Ego-motion based on EM for bionic navigation

    Science.gov (United States)

    Yue, Xiaofeng; Wang, L. J.; Liu, J. G.

    2015-12-01

    Researches have proved that flying insects such as bees can achieve efficient and robust flight control, and biologists have explored some biomimetic principles regarding how they control flight. Based on those basic studies and principles acquired from the flying insects, this paper proposes a different solution of recovering ego-motion for low level navigation. Firstly, a new type of entropy flow is provided to calculate the motion parameters. Secondly, EKF, which has been used for navigation for some years to correct accumulated error, and estimation-Maximization, which is always used to estimate parameters, are put together to determine the ego-motion estimation of aerial vehicles. Numerical simulation on MATLAB has proved that this navigation system provides more accurate position and smaller mean absolute error than pure optical flow navigation. This paper has done pioneering work in bionic mechanism to space navigation.

  7. Radar Landmass Simulation Computer Programming (Interim Report).

    Science.gov (United States)

    RADAR SCANNING, TERRAIN), (*NAVAL TRAINING, RADAR OPERATORS), (*FLIGHT SIMULATORS, TERRAIN AVOIDANCE), (* COMPUTER PROGRAMMING , INSTRUCTION MANUALS), PLAN POSITION INDICATORS, REAL TIME, DISPLAY SYSTEMS, RADAR IMAGES, SIMULATION

  8. A Memory-Based Approach to Two-Player Texas Hold'em

    Science.gov (United States)

    Rubin, Jonathan; Watson, Ian

    A Case-Based Reasoning system, nicknamed SARTRE, that uses a memory-based approach to play two-player, limit Texas Hold'em is introduced. SARTRE records hand histories from strong players and attempts to re-use this information to handle novel situations. SARTRE'S case features and their representations are described, followed by the results obtained when challenging a world-class computerised opponent. Our experimental methodology attempts to address how well SARTRE'S performance can approximate the performance of the expert player, who SARTRE originally derived the experience-base from.

  9. Wind Profiling Radar

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Clutter present in radar return signals as used for wind profiling is substantially removed by carrying out a Daubechies wavelet transformation on a time series of...

  10. Imaging Radar Polarimetry

    Science.gov (United States)

    vanZyl, J. J.; Zebker, H. A.

    1993-01-01

    In this paper, we review the state of the art in imaging radar polarimetry, examine current developments in sensor technology and implementation for recording polarimetric measurements, and describe techniques and areas of application for the new remote sensing data.

  11. Downhole pulse radar

    Science.gov (United States)

    Chang, Hsi-Tien

    1987-09-28

    A borehole logging tool generates a fast rise-time, short duration, high peak-power radar pulse having broad energy distribution between 30 MHz and 300 MHz through a directional transmitting and receiving antennas having barium titanate in the electromagnetically active region to reduce the wavelength to within an order of magnitude of the diameter of the antenna. Radar returns from geological discontinuities are sampled for transmission uphole. 7 figs.

  12. Detecting and classifying low probability of intercept radar

    CERN Document Server

    Pace, Phillip E

    2003-01-01

    The drive is on to devise LPI radar systems that evade hostile detection as well as develop non-cooperative intercept devices that outsmart enemy LPI radar. Based on the author's own design experience, this comprehensive, hands-on book gives you the latest design and development techniques to innovate new LPI radar systems and discover new ways to intercept enemy LPI radar. and help you visually identify waveform parameters. Filled with more than 500 equations that provide rigorous mathematical detail, this book can be used by both entry-level and seasoned engineers. Besides thoroughly treatin

  13. Moving target detection for frequency agility radar by sparse reconstruction

    Science.gov (United States)

    Quan, Yinghui; Li, YaChao; Wu, Yaojun; Ran, Lei; Xing, Mengdao; Liu, Mengqi

    2016-09-01

    Frequency agility radar, with randomly varied carrier frequency from pulse to pulse, exhibits superior performance compared to the conventional fixed carrier frequency pulse-Doppler radar against the electromagnetic interference. A novel moving target detection (MTD) method is proposed for the estimation of the target's velocity of frequency agility radar based on pulses within a coherent processing interval by using sparse reconstruction. Hardware implementation of orthogonal matching pursuit algorithm is executed on Xilinx Virtex-7 Field Programmable Gata Array (FPGA) to perform sparse optimization. Finally, a series of experiments are performed to evaluate the performance of proposed MTD method for frequency agility radar systems.

  14. Orbit Determination Using a Decametric Line-of-Sight Radar

    Science.gov (United States)

    Frazer, G.; Meehan, D.; Rutten, M.; Gordon, N.

    2013-09-01

    The paper investigates the effectiveness of a ground-based bistatic decametric line-of-sight radar for orbit determination of low Earth orbit satellites. Radar observations of the Hubble Space Telescope are used to demonstrate our approach. We present methods for initial orbit determination and for the case of improving an a-priori established orbit descriptor. We discuss the suitability of this class of radar for wide-field space situational awareness and consider a SSA architecture that uses this class of radar to cue high-accuracy narrow field-of-view optical sensors as part of a wide-field high-accuracy system for SSA.

  15. Feasibility of mitigating the effects of windfarms on primary radar

    Energy Technology Data Exchange (ETDEWEB)

    Butler, M.M.; Johnson, D.A.

    2003-07-01

    The objectives of the study were to investigate the feasibility of modifying civil and military radars to mitigate the effects from wind turbines, to provide costings for implementing changes to the radar and to produce guidelines for planning wind farms in the vicinity of radars. The effect of wind turbines on radar signals, assessed through computer modelling, is summarised. The key aspects of turbine design that can be modified to minimise these effects are described. A key issue is the fact that no two radar installations are alike, with settings being customised for local requirements. As a consequence, a detailed understanding of the design and features of each individual radar would be required in order to assess the impact of a wind farm proposal. The costs of a programme of modifications to the civil ATC (air traffic control) radar base will depend on many factors. An estimate of costs is provided, based on the assumption that only 30 of the UK radars would need modification and that a range of modifications from very simple to very complex will be required. A number of other approaches, outside of modification of the radar system, may require investigation during a windfarm planning application, such as layout and location of the wind farm or changing air traffic routes in the vicinity of the wind farm.

  16. Detection Performance Assessment of Ground-Based Phased Array Radar for Ballistic Targets%地基相控阵雷达对弹道目标的探测性能评估

    Institute of Scientific and Technical Information of China (English)

    李星星; 姚汉英; 孙文峰

    2014-01-01

    为解决地基相控阵雷达对弹道目标探测的最优部署问题,建立弹道中段目标轨道运动和进动模型,提出弹道中段多部地基相控阵雷达的弹道目标探测概率模型,以及平均检测概率、稳定跟踪时间和资源冗余时间3种组合的雷达探测性能评估指标。依据弹道目标RCS及探测距离随观测时间的变化情况,通过仿真实验对多种部署方式下地基雷达对弹道目标探测性能评估指标的分析,得出的结论为弹道导弹防御系统中地基雷达的部署方式提供了有效的参考依据。%In order to solve the optimal deployment problem of ground-based phased array radar in detecting ballistic targets,the orbit motion and precession motion models of ballistic targets were built up,and the detection probability model for ballistic targets by using several ground-based phased array radars was proposed.Three evaluation indexes of radars'detection performance were given: average detection probability,stable tracking time and resource redundancy time .According to the variation of RCS and detection range for ballistic targets in midcourse,detection performance evaluation indexes of several radar deployment schemes were analyzed through experiments .The conclusion in this paper may provide some reference for deploying the ground-based radar in ballistic missile defense (BMD) system for targets'optimal detection.

  17. Cultivo de orquídea em substratos à base de casca de café

    Directory of Open Access Journals (Sweden)

    Adriane Marinho de Assis

    2011-01-01

    Full Text Available A utilização de resíduos agrícolas como substrato é uma alternativa promissora no cultivo de orquídeas, reduzindo os custos e o acúmulo desses materiais no ambiente. O objetivo do trabalho foi avaliar o desenvolvimento de orquídea híbrida (C. forbesii x C. labiata x C. labiata em substratos à base de casca de café. O delineamento experimental utilizado foi o inteiramente casualizado, com seis tratamentos (xaxim desfibrado; casca de café; casca de café + coco em pó; casca de café + fibra de coco; casca de café + casca de pinus; casca de café + casca de arroz carbonizada e dez repetições. Após 24 meses avaliou-se a altura da parte aérea; número de brotos; número de flores; diâmetro do maior pseudobulbo; comprimento da maior raiz e a matéria seca de raízes. Foi efetuada avaliação química, pH, condutividade elétrica, densidade e capacidade de retenção de água dos substratos, exceto a composição química dos substratos à base de coco. Não houve diferença significativa quanto à altura da parte aérea, ao número de flores e à matéria seca de raízes, com 33,0 cm; 1,1 e 3,5g, em média, respectivamente. Com relação à casca de café e as suas misturas, não houve diferença quanto ao comprimento da maior raiz. Quanto ao número de brotos e diâmetro do maior pseudobulbo, a mistura de casca de café com coco em pó mostrou-se superior para essas duas variáveis e a mistura de casca de café com casca de arroz carbonizada propiciou o aumento no número de brotos. A casca de café pode ser utilizada como substrato no cultivo de orquídea híbrida (C. forbesii x C. labiata x C. labiata, especialmente em mistura com o coco em pó ou a casca de arroz carbonizada, não sendo indicada como substrato único.

  18. Identification of topographic elements composition based on landform boundaries from radar interferometry segmentation (preliminary study on digital landform mapping)

    Science.gov (United States)

    Widyatmanti, Wirastuti; Wicaksono, Ikhsan; Dinta Rahma Syam, Prima

    2016-06-01

    Dense vegetation that covers most landscapes in Indonesia becomes a common limitation in mapping the landforms in tropical region. This paper aims to examine the use of radar interferometry for landform mapping in tropical region; to examine the application of segmentation method to develop landform type boundaries; and to identify the topographic elements composition for each type of landform. Using Idrisi® and “eCognition ®” softwares, toposhape analysis, segmentation and multi-spectral classification were applied to identify the composition of topographic elements i.e. the types of land-cover from Landsat 8, elevation, slope, relief intensity and curvatures from SRTM (DEM). Visual interpretation on DEM and land-cover fusion imagery was conducted to derive basic control maps of landform and land-cover. The result shows that in segmentation method, shape and compactness levels are essential in obtaining land-cover, elevation, and slope class units to determine the most accurate class borders of each element. Despite a complex procedure applied in determining landform classification, the combination of topographic elements segmentation result presents a distinct border of each landform class. The comparison between landform maps derived from segmentation process and visual interpretation method demonstrates slight dissimilarities, meaning that multi-stage segmentation approach can improve and provide more effective digital landform mapping method in tropical region. Topographic elements on each type of landforms show distinctive composition key containing the percentage of each curvature elements per area unit. Supported by GIS programming and modeling in the future, this finding is significant in reducing effort in landform mapping using visual interpretation method for a very large coverage but in detail scale level.

  19. Research-Based Course Materials and Assessments for Upper-Division Electrodynamics (E&M II)

    CERN Document Server

    Baily, Charles; Pollock, Steven J

    2012-01-01

    Favorable outcomes from ongoing research at the University of Colorado Boulder on student learning in junior-level electrostatics (E&M I) have led us to extend this work to upper-division electrodynamics (E&M II). We describe here our development of a set of research-based instructional materials designed to actively engage students during lecture (including clicker questions and other in-class activities); and an instrument for assessing whether our faculty-consensus learning goals are being met. We also discuss preliminary results from several recent implementations of our transformed curriculum, plans for the dissemination and further refinement of these materials, and offer some insights into student difficulties in advanced undergraduate electromagnetism.

  20. Urban Flood Warning Systems using Radar Technologies

    Science.gov (United States)

    Fang, N.; Bedient, P. B.

    2013-12-01

    There have been an increasing number of urban areas that rely on weather radars to provide accurate precipitation information for flood warning purposes. As non-structural tools, radar-based flood warning systems can provide accurate and timely warnings to the public and private entities in urban areas that are prone to flash floods. The wider spatial and temporal coverage from radar increases flood warning lead-time when compared to rain and stream gages alone. The Third Generation Rice and Texas Medical Center (TMC) Flood Alert System (FAS3) has been delivering warning information with 2 to 3 hours of lead time and a R2 value of 93% to facility personnel in a readily understood format for more than 50 events in the past 15 years. The current FAS utilizes NEXRAD Level II radar rainfall data coupled with a real-time hydrologic model (RTHEC-1) to deliver warning information. The system has a user-friendly dashboard to provide rainfall maps, Google Maps based inundation maps, hydrologic predictions, and real-time monitoring at the bayou. This paper will evaluate its reliable performance during the recent events occurring in 2012 and 2013 and the development of a similar radar-based flood warning system for the City of Sugar Land, Texas. Having a significant role in the communication of flood information, FAS marks an important step towards the establishment of an operational and reliable flood warning system for flood-prone urban areas.