Pub Date : 2009-05-04DOI: 10.1109/RADAR.2009.4977141
H. Ghaemi, M. Viberg, M. Galletti, T. Boerner, F. Gekat
This paper addresses the non-iterative quality phase gradient autofocus (QPGA) technique which was originally proposed to remove one-dimensional phase errors in spotlight-mode synthetic aperture radar (SAR) imagery. By enriching the source pool, the method is modified in a way suitable for autofocus in stripmap-mode SAR system with the advantage of being independent of any priori assumptions. Unlike the QPGA the potential candidates, i.e., dominant scatterers located along azimuth in each specific range bin, are automatically selected by exploiting the one-dimensional RELAX algorithm. Furthermore, RELAX is capable of estimating the size of blur window which is, in fact, associated with the Doppler spread of signal spectrum. The corresponding model includes four parameters i.e., complex amplitude, delay, Doppler center and spectral width. The proposed method has been applied to data extracted by a ground-based rotating coherent Doppler radar operating in strip-mapping mode SAR, with the aim of high-resolution clutter detection.
{"title":"RELAX-based autofocus algorithm for high-resolution strip-map SAR","authors":"H. Ghaemi, M. Viberg, M. Galletti, T. Boerner, F. Gekat","doi":"10.1109/RADAR.2009.4977141","DOIUrl":"https://doi.org/10.1109/RADAR.2009.4977141","url":null,"abstract":"This paper addresses the non-iterative quality phase gradient autofocus (QPGA) technique which was originally proposed to remove one-dimensional phase errors in spotlight-mode synthetic aperture radar (SAR) imagery. By enriching the source pool, the method is modified in a way suitable for autofocus in stripmap-mode SAR system with the advantage of being independent of any priori assumptions. Unlike the QPGA the potential candidates, i.e., dominant scatterers located along azimuth in each specific range bin, are automatically selected by exploiting the one-dimensional RELAX algorithm. Furthermore, RELAX is capable of estimating the size of blur window which is, in fact, associated with the Doppler spread of signal spectrum. The corresponding model includes four parameters i.e., complex amplitude, delay, Doppler center and spectral width. The proposed method has been applied to data extracted by a ground-based rotating coherent Doppler radar operating in strip-mapping mode SAR, with the aim of high-resolution clutter detection.","PeriodicalId":346898,"journal":{"name":"2009 IEEE Radar Conference","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123937186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-05-04DOI: 10.1109/RADAR.2009.4976954
Ya-Nan Li, Yaowen Fu, Xiang Li, Lewei Li
When multiple radar targets are close to each other, the returned signals from these targets are overlapped in time. The translational motion can be viewed as a uniformly accelerated motion, therefore, the Doppler variation of echoes in the cross-range direction can be approximated by the first-order polynomial which is called linear frequency modulation signal. For different targets, the chirp rates are different from each other. In this paper, a new algorithm based on fractional Fourier technique is proposed to separate the signals from different targets in each cross-range cell. By the CLEAN technique, the number of targets need not be specified. We derive original algorithms to compensate the motion of each target signal, so the image of each target can be obtained. The simulation results are given to demonstrate the efficiency of the proposed algorithm for multiple moving targets imaging.
{"title":"An ISAR imaging method for multiple moving targets based on fractional Fourier transformation","authors":"Ya-Nan Li, Yaowen Fu, Xiang Li, Lewei Li","doi":"10.1109/RADAR.2009.4976954","DOIUrl":"https://doi.org/10.1109/RADAR.2009.4976954","url":null,"abstract":"When multiple radar targets are close to each other, the returned signals from these targets are overlapped in time. The translational motion can be viewed as a uniformly accelerated motion, therefore, the Doppler variation of echoes in the cross-range direction can be approximated by the first-order polynomial which is called linear frequency modulation signal. For different targets, the chirp rates are different from each other. In this paper, a new algorithm based on fractional Fourier technique is proposed to separate the signals from different targets in each cross-range cell. By the CLEAN technique, the number of targets need not be specified. We derive original algorithms to compensate the motion of each target signal, so the image of each target can be obtained. The simulation results are given to demonstrate the efficiency of the proposed algorithm for multiple moving targets imaging.","PeriodicalId":346898,"journal":{"name":"2009 IEEE Radar Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114864220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-05-04DOI: 10.1109/RADAR.2009.4977067
A. Kochhar, J. Rottier, A. Weaver, R. E. Trepkowski, R. Marshall
On 14 November 2007, the Johns Hopkins University Applied Physics Laboratory (JHU/APL) provided environmental characterization support for a US Navy radar test event, off the coast of Wallops Island, VA. Two environmental sensor systems were deployed: (1) the Automated Environmental Assessment System installed aboard the research vessel Chessie and (2) the Helicopter Atmospheric Profiler System. Chessie was located on the test range to collect near-surface environmental data in support of evaporation ducting assessments, as well as atmospheric soundings via rocketsondes to characterize upper-air refractivity conditions. Two types of helicopter flight profiles characterized evaporation and surface-based ducts. This paper summarizes the collected data, the propagation analysis, and highlights how a subtle change in meteorological conditions can significantly affect radar propagation. In addition, an analysis of the impact on radar system performance, due to the change in radar propagation conditions, is presented.
{"title":"Surface-based ducting due to a shift in air masses off the coast of Wallops Island, Virginia","authors":"A. Kochhar, J. Rottier, A. Weaver, R. E. Trepkowski, R. Marshall","doi":"10.1109/RADAR.2009.4977067","DOIUrl":"https://doi.org/10.1109/RADAR.2009.4977067","url":null,"abstract":"On 14 November 2007, the Johns Hopkins University Applied Physics Laboratory (JHU/APL) provided environmental characterization support for a US Navy radar test event, off the coast of Wallops Island, VA. Two environmental sensor systems were deployed: (1) the Automated Environmental Assessment System installed aboard the research vessel Chessie and (2) the Helicopter Atmospheric Profiler System. Chessie was located on the test range to collect near-surface environmental data in support of evaporation ducting assessments, as well as atmospheric soundings via rocketsondes to characterize upper-air refractivity conditions. Two types of helicopter flight profiles characterized evaporation and surface-based ducts. This paper summarizes the collected data, the propagation analysis, and highlights how a subtle change in meteorological conditions can significantly affect radar propagation. In addition, an analysis of the impact on radar system performance, due to the change in radar propagation conditions, is presented.","PeriodicalId":346898,"journal":{"name":"2009 IEEE Radar Conference","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124434213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-05-04DOI: 10.1109/RADAR.2009.4977012
F. Lombardini, M. Pardini
Processing of multibaseline/multitemporal SAR data from complex urban or infrastructure areas is of increasing interest. In this framework, the detection of single and multiple layover scatterers is an important problem, for an extensive and accurate signal interpretation. Recently, an hybrid 3D adaptive tomography-complex data domain model fitting detection method has been proposed. In this work, the basic method is tested with simulated data corrupted by non-idealities, in particular residual atmospheric compensation errors. Afterwards, the analyzed effects specific of the presence of the data non-idealities are taken into account for a more robust design of a detection method based on the same principle. The effectiveness of the algorithm is experimented with real satellite C-band data.
{"title":"Detection of scatterer multiplicity in spaceborne SAR tomography with array errors","authors":"F. Lombardini, M. Pardini","doi":"10.1109/RADAR.2009.4977012","DOIUrl":"https://doi.org/10.1109/RADAR.2009.4977012","url":null,"abstract":"Processing of multibaseline/multitemporal SAR data from complex urban or infrastructure areas is of increasing interest. In this framework, the detection of single and multiple layover scatterers is an important problem, for an extensive and accurate signal interpretation. Recently, an hybrid 3D adaptive tomography-complex data domain model fitting detection method has been proposed. In this work, the basic method is tested with simulated data corrupted by non-idealities, in particular residual atmospheric compensation errors. Afterwards, the analyzed effects specific of the presence of the data non-idealities are taken into account for a more robust design of a detection method based on the same principle. The effectiveness of the algorithm is experimented with real satellite C-band data.","PeriodicalId":346898,"journal":{"name":"2009 IEEE Radar Conference","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126467518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-05-04DOI: 10.1109/RADAR.2009.4977015
J. Schuerger, D. Garmatyuk
The paper examines the performance of randomly generated OFDM waveforms in presence of deception jamming. The scenario of interest uses OFDM waveforms for synthetic aperture radar (SAR) imaging of a target area into which a digital radio frequency memory (DRFM) repeat jammer has been introduced. The jammer attempts to introduce false targets into the final image by replicating the radar transmitted waveform. SAR images are often constructed using a back projection algorithm requiring the presence of a false target to rely heavily on the matched filter (MF) output of the radar and jamming signals. Monte Carlo simulations are performed to determine probability density functions for maximum MF output for both cross-correlation and auto-correlation of the random OFDM waveforms containing WGN. A MF threshold is then chosen and probability of false alarm and probability of detection are simulated for varying SNRs.
{"title":"Performance of random OFDM radar signals in deception jamming scenarios","authors":"J. Schuerger, D. Garmatyuk","doi":"10.1109/RADAR.2009.4977015","DOIUrl":"https://doi.org/10.1109/RADAR.2009.4977015","url":null,"abstract":"The paper examines the performance of randomly generated OFDM waveforms in presence of deception jamming. The scenario of interest uses OFDM waveforms for synthetic aperture radar (SAR) imaging of a target area into which a digital radio frequency memory (DRFM) repeat jammer has been introduced. The jammer attempts to introduce false targets into the final image by replicating the radar transmitted waveform. SAR images are often constructed using a back projection algorithm requiring the presence of a false target to rely heavily on the matched filter (MF) output of the radar and jamming signals. Monte Carlo simulations are performed to determine probability density functions for maximum MF output for both cross-correlation and auto-correlation of the random OFDM waveforms containing WGN. A MF threshold is then chosen and probability of false alarm and probability of detection are simulated for varying SNRs.","PeriodicalId":346898,"journal":{"name":"2009 IEEE Radar Conference","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126560422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-05-04DOI: 10.1109/RADAR.2009.4977119
W. Johnson, P. Rosen, S. Hensley, A. Freeman
The interferometric radar (InSAR) design has undergone several iterations in the years that this mission has been under consideration. In the most recent proposal the InSAR is combined with a Lidar and the mission is called Deformation, Ecosystem Structure, and Dynamics of Ice (DESDynI). This spacecraft would be in a near-polar orbit around the Earth and repeatedly collect data to monitor changes in the solid Earth, vegetation, and ice. The radar is a repeat pass interferometric SAR with dual and quad polarization capability. This paper examines the state of the configuration of the radar including a “SweepSAR” method that has been incorporated as the present baseline.
{"title":"Radar designs for the DESDynI mission","authors":"W. Johnson, P. Rosen, S. Hensley, A. Freeman","doi":"10.1109/RADAR.2009.4977119","DOIUrl":"https://doi.org/10.1109/RADAR.2009.4977119","url":null,"abstract":"The interferometric radar (InSAR) design has undergone several iterations in the years that this mission has been under consideration. In the most recent proposal the InSAR is combined with a Lidar and the mission is called Deformation, Ecosystem Structure, and Dynamics of Ice (DESDynI). This spacecraft would be in a near-polar orbit around the Earth and repeatedly collect data to monitor changes in the solid Earth, vegetation, and ice. The radar is a repeat pass interferometric SAR with dual and quad polarization capability. This paper examines the state of the configuration of the radar including a “SweepSAR” method that has been incorporated as the present baseline.","PeriodicalId":346898,"journal":{"name":"2009 IEEE Radar Conference","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132509656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-05-04DOI: 10.1109/RADAR.2009.4976964
K. Chetty, G. Smith, Hui Guo, K. Woodbridge
The rapid rollout of wireless local area networks (WLANs) has provided a ubiquitous source of signal transmissions that may be exploited for surveillance applications using passive bistatic radar (PBR) and passive multistatic radar (PMR) systems. In this study, a series of experiments were conducted to examine the feasibility of using IEEE 802.11 wireless fidelity (WiFi) transmissions for detecting uncooperative targets in high clutter indoor environments. The range and Doppler characteristics of the system were also assessed theoretically from an ambiguity function analysis on WiFi signals having similar transmission parameters. Through-wall detections of personnel targets moving at differing velocities within an indoor environment are presented for the first time. The work demonstrates the feasibility for developing a low cost surveillance device that utilises WiFi networks as transmitters of opportunity.
{"title":"Target detection in high clutter using passive bistatic WiFi radar","authors":"K. Chetty, G. Smith, Hui Guo, K. Woodbridge","doi":"10.1109/RADAR.2009.4976964","DOIUrl":"https://doi.org/10.1109/RADAR.2009.4976964","url":null,"abstract":"The rapid rollout of wireless local area networks (WLANs) has provided a ubiquitous source of signal transmissions that may be exploited for surveillance applications using passive bistatic radar (PBR) and passive multistatic radar (PMR) systems. In this study, a series of experiments were conducted to examine the feasibility of using IEEE 802.11 wireless fidelity (WiFi) transmissions for detecting uncooperative targets in high clutter indoor environments. The range and Doppler characteristics of the system were also assessed theoretically from an ambiguity function analysis on WiFi signals having similar transmission parameters. Through-wall detections of personnel targets moving at differing velocities within an indoor environment are presented for the first time. The work demonstrates the feasibility for developing a low cost surveillance device that utilises WiFi networks as transmitters of opportunity.","PeriodicalId":346898,"journal":{"name":"2009 IEEE Radar Conference","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134355443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-05-04DOI: 10.1109/RADAR.2009.4977041
M. Leifer
It is well known that the area of a synthetic aperture radar (SAR) antenna must exceed a minimum value to avoid image ambiguities. The classic minimum ambiguity-free area criterion was derived for rectangular antennas that are aligned with the direction of travel and are rolled to the look angle. This paper derives an analogous criterion that is valid for nadir-facing, yawed, and non-rectangular antenna geometries. The resulting maximum beam area criterion (MAXBAC) includes the classic result as a special case for rectangular antennas of conventional orientation. It is shown theoretically, and verified numerically for representative examples, that using an unconventional antenna geometry does not improve main beam ambiguity performance.
{"title":"SAR ambiguities in skewed antenna arrays","authors":"M. Leifer","doi":"10.1109/RADAR.2009.4977041","DOIUrl":"https://doi.org/10.1109/RADAR.2009.4977041","url":null,"abstract":"It is well known that the area of a synthetic aperture radar (SAR) antenna must exceed a minimum value to avoid image ambiguities. The classic minimum ambiguity-free area criterion was derived for rectangular antennas that are aligned with the direction of travel and are rolled to the look angle. This paper derives an analogous criterion that is valid for nadir-facing, yawed, and non-rectangular antenna geometries. The resulting maximum beam area criterion (MAXBAC) includes the classic result as a special case for rectangular antennas of conventional orientation. It is shown theoretically, and verified numerically for representative examples, that using an unconventional antenna geometry does not improve main beam ambiguity performance.","PeriodicalId":346898,"journal":{"name":"2009 IEEE Radar Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130906113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-05-04DOI: 10.1109/RADAR.2009.4977010
K. Yu
This paper describes several digital beamforming radar techniques for improving target detection and determination of the angular location of a target using multiple simultaneous received beams. These techniques improve target search and angle estimation performance over the conventional monopulse processing in the elimination of beam-shape loss.
{"title":"Digital beamforming of multiple simultaneous beams for improved target search","authors":"K. Yu","doi":"10.1109/RADAR.2009.4977010","DOIUrl":"https://doi.org/10.1109/RADAR.2009.4977010","url":null,"abstract":"This paper describes several digital beamforming radar techniques for improving target detection and determination of the angular location of a target using multiple simultaneous received beams. These techniques improve target search and angle estimation performance over the conventional monopulse processing in the elimination of beam-shape loss.","PeriodicalId":346898,"journal":{"name":"2009 IEEE Radar Conference","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133209267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-05-04DOI: 10.1109/RADAR.2009.4976988
Rui Min, Xiaobo Yang, Zhiqin Zhao
In this paper, a method of polarimetric SAR image classification based on polarimetric decomposition and AdaBoost algorithm is proposed. The proposed method improves classification accuracy and speed. AdaBoost algorithm, as a robust learner with high accuracy, can fully utilize the polarimetric features to achieve image classification. In simulated tests, the proposed method is observed to produce improved classification accuracy and speed, compared with H /α̅ classification algorithm.
{"title":"Application of AdaBoost in polarimetric SAR image classification","authors":"Rui Min, Xiaobo Yang, Zhiqin Zhao","doi":"10.1109/RADAR.2009.4976988","DOIUrl":"https://doi.org/10.1109/RADAR.2009.4976988","url":null,"abstract":"In this paper, a method of polarimetric SAR image classification based on polarimetric decomposition and AdaBoost algorithm is proposed. The proposed method improves classification accuracy and speed. AdaBoost algorithm, as a robust learner with high accuracy, can fully utilize the polarimetric features to achieve image classification. In simulated tests, the proposed method is observed to produce improved classification accuracy and speed, compared with H /α̅ classification algorithm.","PeriodicalId":346898,"journal":{"name":"2009 IEEE Radar Conference","volume":"150 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134464337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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