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C-band, 4-8 GHz, inverse synthetic aperture radar (ISAR) experiments have been conducted to investigate the characteristics of a proposed synthetic aperture radar (SAR) system using circularly polarized antennas. The aluminum plat...
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C-band, 4-8 GHz, inverse synthetic aperture radar (ISAR) experiments have been conducted to investigate the characteristics of a proposed synthetic aperture radar (SAR) system using circularly polarized antennas. The aluminum plate and dihedral reflectors were selected as targets to analyze the difference of scattering between odd-numbered and even-numbered bounce. SAR measurements with linearly polarized antennas were also performed for comparison. The SAR images show clear differences between co-polarization and cross-polarization setup of the antenna, and is consistent with theory.
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摘要 :
C-band, 4-8 GHz, inverse synthetic aperture radar (ISAR) experiments have been conducted to investigate the characteristics of a proposed synthetic aperture radar (SAR) system using circularly polarized antennas. The aluminum plat...
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C-band, 4-8 GHz, inverse synthetic aperture radar (ISAR) experiments have been conducted to investigate the characteristics of a proposed synthetic aperture radar (SAR) system using circularly polarized antennas. The aluminum plate and dihedral reflectors were selected as targets to analyze the difference of scattering between odd-numbered and even-numbered bounce. SAR measurements with linearly polarized antennas were also performed for comparison. The SAR images show clear differences between co-polarization and cross-polarization setup of the antenna, and is consistent with theory.
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The traditional approach to inverse synthetic aperture radar translational motion compensation is to solve the problem in the two distinct parts of range alignment and autofocus. In this paper, we follow this practice and propose ...
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The traditional approach to inverse synthetic aperture radar translational motion compensation is to solve the problem in the two distinct parts of range alignment and autofocus. In this paper, we follow this practice and propose an approach based on the global range alignment and contrast optimization autofocus methods. The proposed range alignment procedure parametrizes the track as a spline polynomial and minimizes the loss function determined by the sum of the squared envelope differences. The necessary numerical global optimization is performed with the differential evolution algorithm. The solution of the autofocus problem is produced with first order numerical optimization, as we solve it by using an expression derived for the gradient of the loss function. In this paper, we consider the back-projection case but the proposed approach is easily extended to other reconstruction techniques. We use simulated inverse synthetic aperture radar data to demonstrate the proposed approach and to illustrate its computational efficiency.
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In this paper the authors present a concept of flexible system for conducting a wide variety of radar measurements at lower terahertz band (75???500 GHz) along with its laboratory implementation. The presented system comprises fou...
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In this paper the authors present a concept of flexible system for conducting a wide variety of radar measurements at lower terahertz band (75???500 GHz) along with its laboratory implementation. The presented system comprises four main parts: a motorized measurement table, a modular analogue intermediary block as well as recording and signal generation hardware and software. A design of the commercial-off-the-shelf (COTS)-based system built in the Radar Techniques Laboratory of the Warsaw University of Technology is presented. Preliminary results obtained using the designed system are also introduced.
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摘要 :
In this paper the authors present a concept of flexible system for conducting a wide variety of radar measurements at lower terahertz band (75???500 GHz) along with its laboratory implementation. The presented system comprises fou...
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In this paper the authors present a concept of flexible system for conducting a wide variety of radar measurements at lower terahertz band (75???500 GHz) along with its laboratory implementation. The presented system comprises four main parts: a motorized measurement table, a modular analogue intermediary block as well as recording and signal generation hardware and software. A design of the commercial-off-the-shelf (COTS)-based system built in the Radar Techniques Laboratory of the Warsaw University of Technology is presented. Preliminary results obtained using the designed system are also introduced.
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The principle of synthetic aperture radar (SAR) and synthetic aperture sonar (SAS) is the same, but there are fundamental differences due to differences in phase velocity, platform speed and imaging geometry. SAR has reached a ver...
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The principle of synthetic aperture radar (SAR) and synthetic aperture sonar (SAS) is the same, but there are fundamental differences due to differences in phase velocity, platform speed and imaging geometry. SAR has reached a very high level of maturity, being available for decades, while SAS only recently has become commercially available. Interferometry uses phase difference between two (or more) SAS/SAR images to estimate the topography of the imaged scene (different sensor position) or the changes in the scene (different sensor time). SAR interferometry is today very sophisticated, using techniques such as repeat-pass image collections over years and multi-baselines for tomographic (or 3D) imaging. SAS interferometry has been demonstrated successfully at numerous occasions, but has yet to reveal its full potential. The Norwegian Defence Research Establishment (FFI) and Kongsberg Maritime have developed the HISAS 1030 interferometric SAS. In this paper, we compare this sensor with current state-of-the-art in spaceborne and airborne interferometric SAR. We have chosen the airborne STAR-4 which is used in commercial topographic mapping, the airborne PAMIR experimental high resolution multifunction SAR, the spaceborne Shuttle Radar Topography Mission (SRTM) X-band radar, and the TanDEM-X dual satellite high resolution SAR. We focus on design and performance measures and discuss subjects which separate the two technologies. HISAS 1030 has larger relative bandwidth and beamwidth than the SAR sensors. The imaging geometry, and range in particular, varies much more for SAS than SAR. This indicates that interferometric processing should be range dependent for SAS and potentially different from SAR.
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Back Projection imaging algorithm, whose low efficiency reduces its applications in practical projects, could work with highly nonuniform apertures. According to this reason, many scholars have presented some Fast Back Projection ...
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Back Projection imaging algorithm, whose low efficiency reduces its applications in practical projects, could work with highly nonuniform apertures. According to this reason, many scholars have presented some Fast Back Projection algorithms based on sub-aperture method. But how to compensate the motion error after sub-aperture dividing is awaited for further studying. The motion compensation method for FBP algorithm at different motion error levels is studied in this paper. Three situations denoting different motion error levels, which are only non-uniform in azimuth aperture, tracks of two-dimensional motion error and highly nonlinear even curvilinear flight tracks, are discussed here. Then it comes to a fast back projection imaging algorithm for arbitrary aperture, and this algorithm needs highly precise position information. Finally, an outside experiment is made to prove the algorithm's availability.
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摘要 :
Back Projection imaging algorithm, whose low efficiency reduces its applications in practical projects, could work with highly nonuniform apertures. According to this reason, many scholars have presented some Fast Back Projection ...
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Back Projection imaging algorithm, whose low efficiency reduces its applications in practical projects, could work with highly nonuniform apertures. According to this reason, many scholars have presented some Fast Back Projection algorithms based on sub-aperture method. But how to compensate the motion error after sub-aperture dividing is awaited for further studying. The motion compensation method for FBP algorithm at different motion error levels is studied in this paper. Three situations denoting different motion error levels, which are only non-uniform in azimuth aperture, tracks of two-dimensional motion error and highly nonlinear even curvilinear flight tracks, are discussed here. Then it comes to a fast back projection imaging algorithm for arbitrary aperture, and this algorithm needs highly precise position information. Finally, an outside experiment is made to prove the algorithm's availability.
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摘要 :
Back Projection imaging algorithm, whose low efficiency reduces its applications in practical projects, could work with highly nonuniform apertures. According to this reason, many scholars have presented some Fast Back Projection ...
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Back Projection imaging algorithm, whose low efficiency reduces its applications in practical projects, could work with highly nonuniform apertures. According to this reason, many scholars have presented some Fast Back Projection algorithms based on sub-aperture method. But how to compensate the motion error after sub-aperture dividing is awaited for further studying. The motion compensation method for FBP algorithm at different motion error levels is studied in this paper. Three situations denoting different motion error levels, which are only non-uniform in azimuth aperture, tracks of two-dimensional motion error and highly nonlinear even curvilinear flight tracks, are discussed here. Then it comes to a fast back projection imaging algorithm for arbitrary aperture, and this algorithm needs highly precise position information. Finally, an outside experiment is made to prove the algorithm's availability.
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摘要 :
Back Projection imaging algorithm, whose low efficiency reduces its applications in practical projects, could work with highly nonuniform apertures. According to this reason, many scholars have presented some Fast Back Projection ...
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Back Projection imaging algorithm, whose low efficiency reduces its applications in practical projects, could work with highly nonuniform apertures. According to this reason, many scholars have presented some Fast Back Projection algorithms based on sub-aperture method. But how to compensate the motion error after sub-aperture dividing is awaited for further studying. The motion compensation method for FBP algorithm at different motion error levels is studied in this paper. Three situations denoting different motion error levels, which are only non-uniform in azimuth aperture, tracks of two-dimensional motion error and highly nonlinear even curvilinear flight tracks, are discussed here. Then it comes to a fast back projection imaging algorithm for arbitrary aperture, and this algorithm needs highly precise position information. Finally, an outside experiment is made to prove the algorithm's availability.
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