A Novel Echo Separation Scheme for Space-Time Waveform-Encoding SAR Based on the Second-Order Cone Programming (SOCP) Beamformer

作     者：Han, Shuo Deng, Yunkai Wang, Wei Zhao, Qingchao Qiu, Jinsong Zhang, Yongwei Chen, Zhen 

作者机构：Univ Chinese Acad Sci Sch Elect Elect & Commun Engn Beijing 100190 Peoples R China Chinese Acad Sci Aerosp Informat Res Inst Dept Space Microwave Remote Sensing Syst Beijing 100190 Peoples R China 

出 版 物：《REMOTE SENSING》 (遥感)

年 卷 期：2022年第14卷第22期

页      面：5888-5888页

核心收录：

学科分类：0830[工学-环境科学与工程（可授工学、理学、农学学位）] 1002[医学-临床医学] 070801[理学-固体地球物理学] 07[理学] 08[工学] 0708[理学-地球物理学] 0816[工学-测绘科学与技术] 

基　　金：National Natural Science Foundation of China Youth Innovation Promotion Association, Chinese Academy of Sciences (CAS) 

主　　题：synthetic aperture radar high-resolution and wide-swath digital beamforming space-time waveform-encoding echo separation second-order cone programming 

摘      要：Space-time waveform-encoding (STWE)-synthetic aperture radar (SAR) is an effective way to accomplish high-resolution and wide-swath (HRWS) imaging. By designing the specific signal transmit mode, the echoes from several subswaths are received within a single receiving window and overlap each other in STWE-SAR. In order to separate the overlapped echoes, the linear-constrained minimum variance (LCMV) beamformer, a single-null beamformer, is typically used. However, the LCMV beamformer has a very narrow and unstable notch depth, which is not sufficient to accurately separate the overlapped echoes with large signal energy differences between subswaths. The issue of signal energy differences in STWE-SAR is first raised in this paper. Moreover, a novel echo separation scheme based on a second-order cone programming (SOCP) beamformer is proposed. The beam pattern generated by the SOCP beamformer allows flexible adjustment of the notch width and depth, which effectively improves the quality of separation results compared to the LCMV beamformer. The simulation results illustrate that the scheme can greatly enhance the performance of echo separation. Furthermore, the experimental results based on the X-band STWE-SAR airborne system not only demonstrate the scheme s effectiveness but also indicate that it holds great promise for future STWE-SAR missions.