Accurate Wide Angle SAR Imaging Based on LS-CS-Residual.

Zhonghao Wei,Yirong Wu,Bingchen Zhang

doi:10.3390/s19030490

Abstract

Wide angle synthetic aperture radar (WASAR) receives data from a large angle, which causes the problem of aspect dependent scattering. regularization is a common compressed sensing (CS) model. The regularization based WASAR imaging method divides the whole aperture into subapertures and reconstructs the subaperture images individually. However, the aspect dependent scattering recovery of it is not accurate. The subaperture images of WASAR can be regarded as the SAR video. The support set among the different frames of SAR video are highly overlapped. Least squares on compressed sensing residuals (LS-CS-Residuals) can reconstruct the time sequences of sparse signals which change slowly with time. This is to replace CS on the observation by CS on the least squares (LS) residual computed using the prior estimate of the support. In this paper, we introduce LS-CS-Residual into WASAR imaging. In the iteration of LS-CS-Residual, the azimuth-range decoupled operators are used to avoid the huge memory cost. Real data processing results show that LS-CS-Residual can estimate the aspect dependent scatterings of the targets more accurately than CS based methods.

Highlights

Wide angle synthetic aperture radar (WASAR) receives echo data from a large angle
Least squares on compressed sensing residual (LS-CS-Residual) [17] is to replace CS on the observation by CS on the least squares (LS) residual computed using the prior estimate of the support
Since the structure information and LS estimate on the support set are adopted in the proposed method, it can recover the aspect dependent scattering more accurately than CS and debiased-CS

Summary

Introduction

Wide angle synthetic aperture radar (WASAR) receives echo data from a large angle. Advances in synthetic aperture radar (SAR) technology have enabled coherent sensing of WASAR. Traditional imaging methods are based on the isotropic assumption It means that the scattering is constant in the synthetic aperture angle, which is not valid in WASAR. Since the support sets of different aspect subaperture images are highly overlapped across the whole aperture [9], this information can be adopted in the subaperture image reconstruction to avoid it. The supports of the scattering centers overlap across the whole aperture This information can be adopted in WASAR imaging. We propose a novel subaperture imaging method based on LS-CS-Residual. Since the structure information and LS estimate on the support set are adopted in the proposed method, it can recover the aspect dependent scattering more accurately than CS and debiased-CS.

WASAR Subaperture Imaging Based on Compressed Sensing

WASAR Imaging Based on LS-CS-Residual

Turntable Data

Gotcha Volumetric SAR DATA

Conclusions