Advanced high-order nonlinear chirp scaling algorithm for high-resolution wide-swath spaceborne SAR  

作　　者：Zhirong MEN Pengbo WANG Jie CHEN Chunsheng LI Wei LIU Wei YANG 

机构地区：[1]School of Electronic and Information Engineering,Beihang University,Bejing 100083,China [2]Electronic and Electronic Engineering Department,Univrsity of Shefeld,Sheffield S13JD,UK

出　　处：《Chinese Journal of Aeronautics》2021年第2期563-575,共13页中国航空学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (No. 61861136008)。

摘　　要：Spaceborne Synthetic Aperture Radar(SAR) is a well-established and powerful imaging technology that can provide high-resolution images of the Earth’s surface on a global scale. For future SAR systems, one of the key capabilities is to acquire images with both high-resolution and wide-swath. In parallel to the evolution of SAR sensors, more precise range models, and effective imaging algorithms are required. Due to the significant azimuth-variance of the echo signal in High-Resolution Wide-Swath(HRWS) SAR, two challenges have been faced in conventional imaging algorithms. The first challenge is constructing a precise range model of the whole scene and the second one is to develop an effective imaging algorithm since existing ones fail to process highresolution and wide azimuth swath SAR data effectively. In this paper, an Advanced High-order Nonlinear Chirp Scaling(A-HNLCS) algorithm for HRWS SAR is proposed. First, a novel Second-Order Equivalent Squint Range Model(SOESRM) is developed to describe the range history of the whole scene, by introducing a quadratic curve to fit the deviation of the azimuth FM rate. Second, a corresponding algorithm is derived, where the azimuth-variance of the echo signal is solved by azimuth equalizing processing and accurate focusing is achieved through a high-order nonlinear chirp scaling algorithm. As a result, the whole scene can be accurately focused through one single imaging processing. Simulations are provided to validate the proposed range model and imaging algorithm.

关 键 词：High-Resolution WideSwath(HRWS) Imaging method Second-Order Equivalent Squint Range Model(SOESRM) Signal processing Synthetic Aperture Radar(SAR) 

分 类 号：V443.5[航空宇航科学与技术—飞行器设计]