Focus High-Resolution Highly Squint SAR Data Using Azimuth-Variant Residual RCMC and Extended Nonlinear Chirp Scaling Based on a New Circle Model

Zhong, Hua; Zhang, Yanjun; Chang, Yuliang; Liu, Erxiao; Tang, Xianghong; Zhang, Jianwu

doi:10.1109/lgrs.2018.2800105

Cited by 26 publications

(15 citation statements)

References 7 publications

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“…As analysed in [ 40 ], the targets in different range bin—with the same

—will be relocated into the same range gate after LRCMC, which introduce azimuth-variance with respect to Doppler parameters. For the purpose of evaluating the azimuth variance of the Doppler parameters, the relationship between coordinates x and y in a certain range bin is given by

where

is the slant range for the given range bin.…”

Section: Motion Modelling and Optimisationmentioning

confidence: 99%

Squinted Airborne Synthetic Aperture Radar Imaging with Unknown Curved Trajectory

Huang

et al. 2020

Sensors

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The imagery of airborne highly squinted synthetic aperture radar (SAR) with curved trajectory is a challenging task due to the translational-variant range cell migration (RCM) and azimuth modulation. However, in most cases of practical application, the curved trajectory cannot be accurately known, which brings greater difficulties to the imaging problem. To accommodate these issues, we propose a novel motion modelling and optimisation based imaging algorithm for the highly squinted SAR with unknown curved trajectory. First, to correct the translational-variant RCM, a coarse-to-fine RCM correction scheme as well as a range perturbation approach is applied. Afterwards, an optimisation model of motion information under the criterion of minimum entropy is built during the azimuth processing by nonlinear chirp scaling (NLCS). Correspondingly, a differential evolution (DE) optimisation strategy is proposed to estimate the motion information in an iterative manner. We empirically compare the proposed algorithms with several state-of-the-art highly squinted curved SAR imaging algorithms. Numerical results show the effectiveness of the proposed method in the case without any prior information of the curved trajectory.

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“…As analysed in [ 40 ], the targets in different range bin—with the same

where

is the slant range for the given range bin.…”

Section: Motion Modelling and Optimisationmentioning

confidence: 99%

Squinted Airborne Synthetic Aperture Radar Imaging with Unknown Curved Trajectory

Huang

et al. 2020

Sensors

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“…For high-resolution squinted synthetic aperture radar (SAR) imaging, various algorithms have been proposed in recent years, including range-Doppler (RD) algorithm [12][13][14], chirp scaling (CS) algorithm [15][16][17][18][19][20][21], omega-K algorithm [22,23], and backprojection (BP) algorithm [24,25]. Because of the high efficiency and precise error compensation, CS algorithm has been widely applied to process the squinted SAR data compared with other algorithms.…”

Section: Imaging Algorithmmentioning

confidence: 99%

“…Wu et al [16] and Sun et al [17] eliminated the RCM with the keystone transform (KT) in the bistatic and monostatic SAR, respectively. Zhong et al [18] utilized the linear range walk correction (LRWC) and bulk RCM correction (BRCMC) to remove the RCM. In the azimuth focusing, [19][20][21] proposed the nonlinear CS (NLCS) algorithm to equalize the azimuthdependent frequency modulation (FM) rate.…”

Section: Imaging Algorithmmentioning

confidence: 99%

Longwall Retreat and Creep Measurement Based on UWB Radar Imaging Method

Shijia

Wang

Liu

2020

Mathematical Problems in Engineering

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The measurement of longwall retreat and creep displacements is of great significance for the safety production of a coal mine. In order to reliably and accurately obtain the longwall retreat and creep displacements, this paper proposes an ultrawideband (UWB) radar imaging method. The bolt plates fixed in the roadway coal wall are imaged as the target points. First, a signal model is built, and a modified nonlinear chirp scaling (NLCS) imaging algorithm is designed to obtain the high-resolution image. Then, the retreat and creep displacements are estimated based on the imaging results. Finally, simulation and experiment are performed. The simulation results show that the radar imaging method is theoretically feasible to measure the retreat and creep displacements. The measurement errors in the experiment are 0.058 m and 0.040 m, respectively. In the experiment, the radar velocity fluctuation and signal attenuation cause the target azimuth and range errors in the imaging results, which makes the measurement errors in the experiment larger than that in the simulation. This method requires no additional roadway information except for the bolt plates fixed in the coal wall. In addition, the signal propagation of UWB radar is rarely affected by the dust and moisture in the harsh environment.

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“…The efficient CZT uses the scaling Fourier transform (SCFT), instead of the Fourier transform, to solve the non-uniform sampling problem [21][22][23][24]. The compression factor is…”

Section: Azimuth Processingmentioning

confidence: 99%

A Fast High-Resolution Imaging Algorithm for Helicopter-Borne Rotating Array SAR Based on 2-D Chirp-Z Transform

et al. 2019

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In view of the azimuth resolution of the helicopter-borne rotating array synthetic aperture radar (RoASAR) depending on the azimuth reconstruction angle and the sector distortion caused by the azimuth Deramp processing, this paper proposes an efficient helicopter-borne RoASAR high-resolution imaging algorithm based on two-dimensional (2-D) chirp-z transform (CZT). First, the high-order Taylor series expansion is performed on the slant range, and the accurate 2-D spectral expression of the point target is obtained by using the method of series reversion (MSR). Based on that, the space-variant characteristics of the range cell migration (RCM) terms are analyzed. After that, the space-variant RCM and the sector distortion effect caused by the azimuth Deramp processing are removed by using efficient 2-D CZT, thereby increasing the azimuth reconstruction angle and improving the azimuth resolution. The proposed algorithm is efficient without the interpolation operation, and it is easy to implement in real-time. Finally, the simulations are provided to verify the effectiveness of the proposed algorithm.

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Focus High-Resolution Highly Squint SAR Data Using Azimuth-Variant Residual RCMC and Extended Nonlinear Chirp Scaling Based on a New Circle Model

Cited by 26 publications

References 7 publications

Squinted Airborne Synthetic Aperture Radar Imaging with Unknown Curved Trajectory

Squinted Airborne Synthetic Aperture Radar Imaging with Unknown Curved Trajectory

Longwall Retreat and Creep Measurement Based on UWB Radar Imaging Method

A Fast High-Resolution Imaging Algorithm for Helicopter-Borne Rotating Array SAR Based on 2-D Chirp-Z Transform

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