摘要 :
A simple ISAR Range-Doppler algorithm is applicable to for steadily small flying target. But for maneuvering target the assumption is not satisfied, as the Doppler frequency is time variation. Actually to obtain the cross-range re...
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A simple ISAR Range-Doppler algorithm is applicable to for steadily small flying target. But for maneuvering target the assumption is not satisfied, as the Doppler frequency is time variation. Actually to obtain the cross-range resolution of dozens of centimeters for the large-scale or medium targets especial for S or L wave band, which wave length is not shorter, the migration through resolution cell (MTRC) would be occurred on the both fringe of the ISAR imaging. In this paper it discuss the reason that caused migration through resolution cell, and a compensating algorithm is proposed. Simulate data and real data prove that this method is effective.
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摘要 :
A simple ISAR Range-Doppler algorithm is applicable to for steadily small flying target. But for maneuvering target the assumption is not satisfied, as the Doppler frequency is time variation. Actually to obtain the cross-range re...
展开
A simple ISAR Range-Doppler algorithm is applicable to for steadily small flying target. But for maneuvering target the assumption is not satisfied, as the Doppler frequency is time variation. Actually to obtain the cross-range resolution of dozens of centimeters for the large-scale or medium targets especial for S or L wave band, which wave length is not shorter, the migration through resolution cell (MTRC) would be occurred on the both fringe of the ISAR imaging. In this paper it discuss the reason that caused migration through resolution cell, and a compensating algorithm is proposed. Simulate data and real data prove that this method is effective.
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摘要 :
Usually inverse synthetic aperture radar (ISAR) imaging is for small aircraft, with long range, moreover the coherent integration angle is small, that is the target's wavenumber spectrum support region can be regard as a rectangle...
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Usually inverse synthetic aperture radar (ISAR) imaging is for small aircraft, with long range, moreover the coherent integration angle is small, that is the target's wavenumber spectrum support region can be regard as a rectangle, Range-Doppler(RD) algorithm or Range-Instantaneous-Doppler (RID) algorithm are employed for image reconstruction after translational motion compensation (TMC), which includes envelope alignment (such as envelope correlation algorithm, minimum entropy algorithm) and autofocus (such as single PPP algorithm, multiple PPP algorithm, PGA, weighted least square algorithm). But migration through resolution cell (MTRC) is not considered after TMC, in fact, the scatterers around the target usually take place MTRC if the size of target is large. In the paper, we first align and focus the high resolution radar target echoes according target center, then we do time scale transform in target's wavenumber domain, that is Soumekh proposed "keystone" interpolation to compensate MTRC (which can also be realized rapidly by DFT-IFFT or SFT-IFFT in azimuth direction), after range compression (range IFFT), for steadily flying target, target image can be obtained only after azimuth compression (that is FFT in azimuth direction), for maneuvering target, time-frequency analysis must be taken for every range cell, and the existing instantaneous imaging algorithms (such as joint time-frequency distribution algorithm, Radon-Wigner algorithm) are also effective to obtain RID images. This paper gives the ISAR imaging algorithm flow diagram to obtain images from raw data of steadily flying and maneuvering big targets, and simulate data and real data prove that algorithm flow is effective.
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摘要 :
Usually inverse synthetic aperture radar (ISAR) imaging is for small aircraft, with long range, moreover the coherent integration angle is small, that is the target's wavenumber spectrum support region can be regard as a rectangle...
展开
Usually inverse synthetic aperture radar (ISAR) imaging is for small aircraft, with long range, moreover the coherent integration angle is small, that is the target's wavenumber spectrum support region can be regard as a rectangle, Range-Doppler(RD) algorithm or Range-Instantaneous-Doppler (RID) algorithm are employed for image reconstruction after translational motion compensation (TMC), which includes envelope alignment (such as envelope correlation algorithm, minimum entropy algorithm) and autofocus (such as single PPP algorithm, multiple PPP algorithm, PGA, weighted least square algorithm). But migration through resolution cell (MTRC) is not considered after TMC, in fact, the scatterers around the target usually take place MTRC if the size of target is large. In the paper, we first align and focus the high resolution radar target echoes according target center, then we do time scale transform in target's wavenumber domain, that is Soumekh proposed 'keystone' interpolation to compensate MTRC (which can also be realized rapidly by DFT-IFFT or SFT-IFFT in azimuth direction), after range compression (range IFFT), for steadily flying target, target image can be obtained only after azimuth compression (that is FFT in azimuth direction), for maneuvering target, time-frequency analysis must be taken for every range cell, and the existing instantaneous imaging algorithms (such as joint time-frequency distribution algorithm, Radon-Wigner algorithm) are also effective to obtain RID images. This paper gives the ISAR imaging algorithm flow diagram to obtain images from raw data of steadily flying and maneuvering big targets, and simulate data and real data prove that algorithm flow is effective.
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摘要 :
In conventional ISAR system, when the requested resolution of radar is high, while the size of target is large, it will cause the Migration Through Resolution Cell(MTRC), it will also exist the same problems in Bistatic ISAR syste...
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In conventional ISAR system, when the requested resolution of radar is high, while the size of target is large, it will cause the Migration Through Resolution Cell(MTRC), it will also exist the same problems in Bistatic ISAR systems. This paper analyzes and discusses the reason of causing MTRC particularly in the module of Bistatic ISAR, and compares it with the situation in Mono ISAR systems. And then a correction algorithm based on Keystone transformation is presented in the paper, which eliminates the MTRC in the targer imaging, Finally, some simulation results are given to validate the validity of the algorithm.
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摘要 :
In conventional ISAR system, when the requested resolution of radar is high, while the size of target is large, it will cause the Migration Through Resolution Cell(MTRC), it will also exist the same problems in Bistatic ISAR syste...
展开
In conventional ISAR system, when the requested resolution of radar is high, while the size of target is large, it will cause the Migration Through Resolution Cell(MTRC), it will also exist the same problems in Bistatic ISAR systems. This paper analyzes and discusses the reason of causing MTRC particularly in the module of Bistatic ISAR, and compares it with the situation in Mono ISAR systems. And then a correction algorithm based on Keystone transformation is presented in the paper, which eliminates the MTRC in the targer imaging, Finally, some simulation results are given to validate the validity of the algorithm.
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摘要 :
In conventional ISAR system,when the requested resolution of radar is high,while the size of target is large,it will cause the Migration Through Resolution Cell(MTRC),it will also exist the same problems in Bistatic ISAR syste...
展开
In conventional ISAR system,when the requested resolution of radar is high,while the size of target is large,it will cause the Migration Through Resolution Cell(MTRC),it will also exist the same problems in Bistatic ISAR systems. This paper analyzes and discusses the reason of causing MTRC particularly in the module of Bistatic ISAR,and compares it with the situation in Mono ISAR systems. And then a correction algorithm based on Keystone transformation is presented in the paper,which eliminates the MTRC in the targer imaging,Finally,some simulation results are given to validate the validity of the algorithm.
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摘要 :
Range-Doppler (RD) method is the most common used method in ISAR imaging. To obtain radar image of a target, certain rotation angle of the target with respect to Radar Line Of Sight during the coherent integration interval is requ...
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Range-Doppler (RD) method is the most common used method in ISAR imaging. To obtain radar image of a target, certain rotation angle of the target with respect to Radar Line Of Sight during the coherent integration interval is required. In such case, there will exist scatterers' migration. Actually, scatterers' Migration Through Resolution Cells (MTRC) will happen inevitably in high resolution radar image, which will result in the point-spread function broadening and image resolution decreasing. The scatterers' migration is discussed in this paper, and a simple and an efficient method is proposed to correct MTRC. Compensation results of the simulated data and the real data collected in a microwave anechoic chamber show that the resolution of the final radar image is improved.
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摘要 :
With the improvement of resolution in the inverse synthetic aperture radar (ISAR) imaging, the effect of the rotational motion of the target is much larger than ever before. In this letter, we propose a novel subimage fusion metho...
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With the improvement of resolution in the inverse synthetic aperture radar (ISAR) imaging, the effect of the rotational motion of the target is much larger than ever before. In this letter, we propose a novel subimage fusion method to compensate for the large rotational motion in high-resolution ISAR imaging. By dividing the large rotational motion into several small ones, the subimage formation can be realized easily with current ISAR imaging algorithms. At the same time, with the increasing of the number of the subimages, the change of the aspect angle during the coherent processing interval can be very large, and high resolution can be achieved. Moreover, because the whole processing is achieved with Fast Fourier Transforms and vector-multiplication operations, the proposed approach is computationally efficient and has no interpolation operation. Numerical examples are provided to demonstrate the performance of the proposed approach.
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摘要 :
With the improvement of resolution in the inverse synthetic aperture radar (ISAR) imaging, the effect of the rotational motion of the target is much larger than ever before. In this letter, we propose a novel subimage fusion metho...
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With the improvement of resolution in the inverse synthetic aperture radar (ISAR) imaging, the effect of the rotational motion of the target is much larger than ever before. In this letter, we propose a novel subimage fusion method to compensate for the large rotational motion in high-resolution ISAR imaging. By dividing the large rotational motion into several small ones, the subimage formation can be realized easily with current ISAR imaging algorithms. At the same time, with the increasing of the number of the subimages, the change of the aspect angle during the coherent processing interval can be very large, and high resolution can be achieved. Moreover, because the whole processing is achieved with Fast Fourier Transforms and vector-multiplication operations, the proposed approach is computationally efficient and has no interpolation operation. Numerical examples are provided to demonstrate the performance of the proposed approach.
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