High-Resolution Forward-Looking Multichannel SAR Imagery With Array Deviation Angle Calibration

Lu, Jingyue; Zhang, Lei; Huang, Yan; Cao, Yunhe

doi:10.1109/tgrs.2020.2977731

Cited by 30 publications

(9 citation statements)

References 32 publications

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“…The occurrence of phase errors during the DBF process can lead to undesirable effects such as spectrum folding and mismatch, which, in turn, result in significant ambiguities in the acquired SAR images. The inclusion of these errors will result in a degradation of the azimuth ambiguity-to-signal ratio (AASR) [ 13 ] in the high-resolution wide-swath (HRWS) imagery.…”

Section: Introductionmentioning

confidence: 99%

Range-Dependent Channel Calibration for High-Resolution Wide-Swath Synthetic Aperture Radar Imagery

Zhang,

Meng,

Wang

et al. 2024

Sensors

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High-resolution and wide-swath (HRWS) synthetic aperture radar (SAR) imaging with azimuth multi-channel always suffers from channel phase and amplitude errors. Compared with spatial-invariant error, the range-dependent channel phase error is intractable due to its spatial dependency characteristic. This paper proposes a novel parameterized channel equalization approach to reconstruct the unambiguous SAR imagery. First, a linear model is established for the range-dependent channel phase error, and the sharpness of the reconstructed Doppler spectrum is used to measure the unambiguity quality. Furthermore, the intrinsic relationship between the channel phase errors and the sharpness is revealed, which allows us to estimate the optimal parameters by maximizing the sharpness of the reconstructed Doppler spectrum. Finally, the results from real-measured data show that the suggested method performs exceptionally for ambiguity suppression in HRWS SAR imaging.

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Section: Introductionmentioning

confidence: 99%

Range-Dependent Channel Calibration for High-Resolution Wide-Swath Synthetic Aperture Radar Imagery

Zhang,

Meng,

Wang

et al. 2024

Sensors

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“…Multichannel radar can also be used to obtain a highresolution image of forward-looking area at the cost of increased system complexity [8]- [11], and its azimuth resolution is limited due to the restriction of platform size [12] [13]. Besides, multichannel forward-looking SAR imaging schemes have been developed in [14] [15], the azimuth resolution can be improved for the area deviated far from the flight direction, but the azimuth resolution in the vicinity of the flight direction is still poor due to the small angle variation.…”

Section: Introductionmentioning

confidence: 99%

LRSD-ADMM-NET: Simultaneous Super- Resolution Imaging and Target Detection for Forward-Looking Scanning Radar

Li,

Zhang,

et al. 2024

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

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Forward-looking imaging and target detection are highly desirable in many military and civilian fields, such as search and rescue, sea surface surveillance, airport surveillance, and guidance. However, during the processing procedure, imaging and target detection are usually regarded as two independent parts, which means that the imaging result will directly affect the detection performance. In this paper, the LRSD-ADMM-net is proposed to achieve simultaneous super-resolution imaging and target detection for forward-looking scanning radar. Firstly, lowrank and sparse constraints as regularization norms are incorporated to establish objective function, and the alternating direction multiplier method (ADMM) is used to solve simultaneous superresolution and target detection problems. Then, the solving process is expanded into a neural network, where the weight parameters of each level are obtained through adaptive learning. At last, experiments are conducted to verify the effectiveness of the proposed method.

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“…When the array error is large enough, the adaptive array processing methods significantly outperform the digital beamforming methods [10]. In order to solve the problem that beamforming‐based methods is sensitive to array error, a maximum likelihood estimation of array deviation angle is performed to eliminate the mismatch between azimuth angle and Doppler frequency in forward‐looking imaging [6], where ambiguous images of each channel are focussed by Doppler beam sharpening (DBS) method. However, although forward‐looking scenes on the left and right can be distinguished by adopting the above methods, the cross‐range resolution of forward‐looking area is still limited by azimuth real aperture.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, there exists the same cone angle on the left and right sides of flight direction. Therefore, scenes on the left and right sides cannot be distinguished in a single-channel SAR system, that is, left-right Doppler is ambiguous [6]. Due to the above two problems, the traditional single-channel SAR system cannot be directly applied in forward-looking imaging.…”

Section: Introductionmentioning

confidence: 99%

Super‐resolution forward‐looking imaging method for manoeuvering platform with optimised dictionary and extended sparsity adaptive matching pursuit

Zhang

Liang

Chen³

et al. 2022

IET Radar Sonar & Navi

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In forward‐looking imaging, left‐right Doppler is ambiguous and cross‐range resolution is limited by real aperture, which result in traditional synthetic aperture radar imaging methods no longer applicable. Besides, the impact of three‐dimensional acceleration on an over‐complete dictionary matrix and sparse reconstruction kernel is not considered in conventional super‐resolution forward‐looking imaging methods. To solve these problems, a super‐resolution forward‐looking imaging method for manoeuvering platforms is proposed. First, the range walk caused by forward‐looking geometry and higher‐order phase introduced by three‐dimensional acceleration are eliminated by compensating a pre‐processing function. Subsequently, according to beam steering‐based geometry and linear regression model, the over‐complete dictionary matrix is optimised to more accurately describe the complicated forward‐looking geometry with curved trajectory. Finally, sparsity adaptive matching pursuit kernel with an improved halting condition is adopted to reconstruct the forward‐looking scene. The proposed method is supported by point target simulation and surface target simulation.

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High-Resolution Forward-Looking Multichannel SAR Imagery With Array Deviation Angle Calibration

Cited by 30 publications

References 32 publications

Range-Dependent Channel Calibration for High-Resolution Wide-Swath Synthetic Aperture Radar Imagery

Range-Dependent Channel Calibration for High-Resolution Wide-Swath Synthetic Aperture Radar Imagery

LRSD-ADMM-NET: Simultaneous Super- Resolution Imaging and Target Detection for Forward-Looking Scanning Radar

Super‐resolution forward‐looking imaging method for manoeuvering platform with optimised dictionary and extended sparsity adaptive matching pursuit

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