Circulate shifted OFDM chirp waveform diversity design with digital beamforming for MIMO SAR

作     者：Shangwen LIU Zenghui ZHANG Wenxian YU 

作者机构：Shanghai Key Laboratory of Intelligent Sensing and Recognition Shanghai Jiao Tong University 

出 版 物：《Science China(Information Sciences)》 (中国科学:信息科学(英文版))

年 卷 期：2017年第60卷第10期

页      面：217-228页

核心收录：

学科分类：080904[工学-电磁场与微波技术] 0810[工学-信息与通信工程] 0808[工学-电气工程] 0809[工学-电子科学与技术（可授工学、理学学位）] 08[工学] 0812[工学-计算机科学与技术（可授工学、理学学位）] 

基　　金：supported in part by National Natural Science Foundation of China(Grant No.61331015) 

主　　题：MIMO SAR Gabor transform cyclic shift OFDM chirp waveform synthetic integral side lobe ratio(SISLR) 

摘      要：Waveform diversity design has always been the key to multiple-input multiple-output(MIMO)synthetic aperture radar(SAR) systems, and it is known that synthetic integral side lobe ratio(SISLR) is a more optimal indicator than the integral side lobe ratio(ISLR) to evaluate the orthogonality between different MIMO SAR waveforms. This paper presents proof that it is difficult to obtain the SISLR of an existing waveform such that it is sufficiently low to achieve high SNR for SAR imaging. Thus, it is necessary to find a way to separate these MIMO SAR waveforms in other domains, for example, a spatial domain by digital beamforming(DBF). Learning from Krieger’s idea of short-term shift-orthogonal waveforms and using joint time-frequency transforms(Gabor transform) to prove that for most existing SAR waveforms cyclic shift is a good operation with which to generate short-term shift-orthogonal waveforms. This paper presents the designs of four circulate shifted OFDM chirp waveforms, which have a much lower SISLR and retain all the advantages of the classical chirp waveform such as a large time-bandwidth product, constant amplitude, implementation simplicity, and good Doppler tolerance.