基于子孔径处理的大斜视SAR点目标仿真  

Point Target Simulation of Large Squint SAR Based on Subaperture Processing

作　　者：吴佳晔 顾丹丹 刘鹏 WU Jiaye;GU Dandan;LIU Peng(Key Laboratory of Electromagnetic Waves Information(MoE),School of Information Science and Technology,Fudan University,Shanghai 200433,China;Key Laboratory of Electromagnetic Scattering,Shanghai Academy of Space Technology,Shanghai 200438,China)

机构地区：[1]复旦大学信息科学与工程学院电磁波信息科学教育部重点实验室,上海200433 [2]上海航天技术研究院电磁散射重点实验室,上海200438

出　　处：《上海航天（中英文）》2021年第5期120-130,共11页Aerospace Shanghai（Chinese&English）

基　　金：国家自然科学基金(61771142,61901269);上海航天科技创新基金(SAST2019-072)。

摘　　要：机载合成孔径雷达(SAR)平台无法在长合成孔径时间内保持理想匀速直线运动,运动参数变化较大。利用全孔径算法进行成像处理,难以高效地生成聚焦良好的图像。针对这些问题,本文通过在回波信号方位向划分子孔径,分段处理,从而得到聚焦良好的图像。为增强适用性,子孔径处理时采用大斜视角下的距离多普勒(RD)算法,同时与传统正侧视及小斜视RD算法比较。经仿真验证:无论在大斜视情况下还是在有运动误差的情况下,本文算法都能使点目标良好聚焦,点散布函数的分布显示旁瓣均低于-20 dB,满足工程使用要求,说明了算法的有效性。The non-ideal motion of the airborne synthetic aperture radar(SAR)platform usually alters the regular phase history,resulting in a degraded image quality.Besides,the difficulties of motion compensation and full-aperture processing are increased with the increasing synthetic aperture time.In order to solve these problems,in this paper,the subapertures are divided in the azimuth direction of the echo signal and processed in sections,by which well-focused images are obtained.Furthermore,in order to enhance the applicability,the Range-Doppler(RD)algorithm under highly squint angle is used in the subaperture processing.The results are compared with those obtained with the traditional RD algorithm for side looking or small squint looking.It is shown that the proposed algorithm can make the point target focus well in both cases of large squint angle and large motion error.The distribution of the point dispersion function shows that all side lobes are lower than-20 dB,which meets the requirements of engineering application and validates the effectiveness of the algorithm.

关 键 词：合成孔径雷达(SAR) 子孔径 大斜视 运动误差 点目标仿真 

分 类 号：TN957.52[电子电信—信号与信息处理]