GMTI for Squint Looking XTI-SAR with Rotatable Forward-Looking Array

Jing, Kai; Xu, Jia; Huang, Zuzhen; Yao, Di; Li, Teng

doi:10.3390/s16060873

Cited by 3 publications

(4 citation statements)

References 23 publications

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“…These scopes are considerably smaller than an aimless traversal. In accordance with Equations (17) and (18), the step-size values of µ 2 and µ 3 are all approximately 0.001. For µ 3 , this step-size is acceptable, and the traversal number (i.e., 61) will not cause complexity, but for µ 2 , the traversal burden (i.e., 2001) of this step-size is unbearable.…”

Section: Step-sizesupporting

confidence: 53%

“…However, the NS-HSV-SAR is preferred when working with a squint angle for flexible and comprehensive detection, to provide further information about the surface structure [15]. To the best of our knowledge, only parts of the methods have been proposed for traditional SAR/GMTI working with a squint angle [16][17][18][19]. Xu et al [16,17] focused on multi-channel GMTI, and Garren [18] mainly concentrated on two-dimensional (2-D) range migration signature analysis of a target.…”

Section: Introductionmentioning

confidence: 99%

“…To the best of our knowledge, only parts of the methods have been proposed for traditional SAR/GMTI working with a squint angle [16][17][18][19]. Xu et al [16,17] focused on multi-channel GMTI, and Garren [18] mainly concentrated on two-dimensional (2-D) range migration signature analysis of a target. In [19], the squint angle is only considered to bound the algorithm performance.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Ground Moving Target Imaging and Analysis for Near-Space Hypersonic Vehicle-Borne Synthetic Aperture Radar System with Squint Angle

et al. 2018

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Near space is the key to integrating “sky” and “space” into the future. A synthetic aperture radar (SAR) that works in this area would initiate a technological revolution for remote sensing applications. This study mainly focused on ground moving target imaging (GMTIm) for a near-space hypersonic vehicle-borne SAR (NS-HSV-SAR) with squint angle. The range history, parameter coupling, and Doppler ambiguity of the squint-looking NS-HSV-SAR are more complicated than traditional side-looking airborne or space-borne SARs. Thus, a precise range model is presented on the basis of phase error analyses. Then, all potential distributions of echo’s azimuth spectrum are derived, and a GMTIm method is proposed on the basis of a detailed analysis of the echo characteristics. The proposed method consists of three steps. Firstly, a prior information-based pre-processing function was created to decrease the Doppler ambiguity and range migration effects. Secondly, a blur matched keystone transform was developed to correct the residual range walk migration. Thirdly, a time-saving chirp Fourier transform was investigated for azimuth focusing. Implementation considerations, including the curvilinear trajectory of the NS-HSV-SAR, multiple moving target imaging, and applicability and limitation of the method, are discussed. Finally, simulation results are presented to validate the effectiveness of the proposed method.

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Section: Step-sizesupporting

confidence: 53%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Ground Moving Target Imaging and Analysis for Near-Space Hypersonic Vehicle-Borne Synthetic Aperture Radar System with Squint Angle

et al. 2018

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“…Characterized by high resolution, cloud penetration, and remote sensing capabilities, synthetic aperture radar (SAR) has been studied intensively in both civil and military applications in recent years [ 1 , 2 , 3 , 4 , 5 , 6 ]. Combined with ground moving targets indication (GMTI) techniques, SAR-GMTI has been developed to be an effective and convenient way to realize moving target localization and recognition in the well-focused image domain [ 7 , 8 , 9 , 10 , 11 , 12 ]. In this case, the accurate focusing of the moving target becomes the most important prerequisite.…”

Section: Introductionmentioning

confidence: 99%

Parameterized Pseudo-Localization for Accurate and Efficient Moving Targets Imaging in Synthetic Aperture Radar

Zhang

Liu

Zhang

2017

Sensors

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Accurate and efficient moving target imaging is an important challenge for targets recognition in current synthetic aperture radar (SAR) combined with a ground moving target indication (GMTI) system. As the key but unknown parameter, the Doppler rates are estimated conventionally by searching any possible values for moving targets imaging. However, this conventional estimation method suffers from low accuracy or low efficiency due to the searching procedure. Focusing on these, we present a method to efficiently image the moving targets without the Doppler rate by Doppler delayed interferometry, and the imaged localization, which is parameterized pseudo-localization, is used to estimate the Doppler rate. In order to improve the estimation accuracy, an improved method based on the Newton method of approximation is proposed by exploiting the unused amplitude information. Compared with the conventional methods, the proposed improved method capable of high accuracy and low computation complexity simultaneously can meet the accurate and efficient requirements in the practical applications. Comparison simulations and real data processing results demonstrate the effectiveness of the proposed methods.

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Ground Moving Target Imaging for Highly Squint SAR by Modified Minimum Entropy Algorithm and Spectrum Rotation

Xiong

Zhang

et al. 2021

Remote Sensing

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Ground moving target (GMT) is displaced and defocused in conventional synthetic aperture radar (SAR) image due to the residual phase error of non-cooperative GMT motion. In this study, a GMT imaging (GMTIm) method is proposed for highly squint SAR. As the squint angle become large, the displace and defocus effect of the GMT image become severe and the geometry distortion of the GMT image cannot be ignored. The proposed method first deduced the two-dimensional (2-D) frequency domain signal of the GMT and the bulk compression function of the Range Migration Algorithm (RMA) in highly squint SAR. Then GMT ROI data are extracted and a modified minimum entropy algorithm (MMEA) is proposed to refocus the GMT image. MMEA introduces the idea of bisection into the iteration process to converge more efficiently than the previous minimum entropy method. To overcome the geometry distortion of the GMT image, an equivalent squint angle spectrum rotation method is proposed. Finally, to suppress the GMT image sidelobe, the sparse characteristic of GMT is considered and a sparse enhancement method is adopted. The proposed method can realize GMTIm in highly squint SAR where the squint angle reaches to 75 degrees. The PSNR and ISLR of point target in highly squint SAR is close to that in side-looking SAR. The simulated point target data and ship data are used to validate the effectiveness of the proposed method.

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GMTI for Squint Looking XTI-SAR with Rotatable Forward-Looking Array

Cited by 3 publications

References 23 publications

Ground Moving Target Imaging and Analysis for Near-Space Hypersonic Vehicle-Borne Synthetic Aperture Radar System with Squint Angle

Ground Moving Target Imaging and Analysis for Near-Space Hypersonic Vehicle-Borne Synthetic Aperture Radar System with Squint Angle

Parameterized Pseudo-Localization for Accurate and Efficient Moving Targets Imaging in Synthetic Aperture Radar

Ground Moving Target Imaging for Highly Squint SAR by Modified Minimum Entropy Algorithm and Spectrum Rotation

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