基于矩阵束方法的星载MEB SAR俯仰向DBF处理方法  

Matrix Pencil Method Based Processing Approach for Spaceborne MEB SAR with Digital Beamforming in Elevation

作　　者：叶恺[1,2] 禹卫东 王伟[1] YE Kai1,2, YU Weidonge1,2, WANG Wei1(1Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China ;2. University of Chinese Academy of Sciences, Beijing 100049, China)

机构地区：[1]中国科学院电子学研究所,北京100190 [2]中国科学院大学,北京100049

出　　处：《电子与信息学报》2018年第11期2659-2666,共8页Journal of Electronics & Information Technology

基　　金：国家重点研发计划(2017YFB0502700);国家自然科学基金(61701479)~~

摘　　要：俯仰向数字波束形成(DBF)处理是距离向多波束体制(MEB)星载合成孔径雷达(SAR)系统实现较高分辨率、超宽幅成像的关键。但是,由于存在卫星姿态误差等因素的影响,星载MEB SAR系统的DBF接收波束指向会出现偏差,这将导致在对具有强散射体的区域(如存在船舶的海面、港口等区域)进行成像时会出现鬼影目标。针对这一问题,该文提出一种基于矩阵束方法的俯仰向DBF处理方法。首先对俯仰向通道回波数据进行匹配滤波处理,并根据预设阈值寻找强散射体的峰值位置;然后利用矩阵束方法准确估计强散射体的波达角;最后利用这些信息调整俯仰向DBF加权矢量,确保DBF接收波束指向正确,从而消除鬼影目标的干扰。仿真实验验证了该方法的有效性。Digital BeamForming （DBF） in elevation plays a crucial role for spaceborne Multiple Elevation Beam （MEB） SAR realizing the High-Resolution Wide-Swath （HRWS） imaging mode. However, due to the influence of satellite attitude error, the deviation of the DBF receiving beam direction always arises in such system. This leads to ghost targets appearing in the SAR image, when mapping the scenes （such as the seaport areas） with strong scatterers. To address the problem, a matrix pencil method based DBF processing approach in elevation is presented. Firstly, according to the given threshold, the peak position of the strong scatterer is found from the range-compressed signals. Then, the direction of arrival angle of the strong scatterer is estimated using the matrix pencil method. Finally, based on the imaging geometry model, the DBF weighting vector is adjusted to ensure the receiving beam to precisely point to the signal sources. Thereby, the interferences of ghost targets in SAR image can be eliminated effectively. The theoretical analysis is derived in detail, then it is validated by simulation experiments.

关 键 词：合成孔径雷达 距离向多波束 数字波束形成 矩阵束方法 

分 类 号：TN959.74[电子电信—信号与信息处理]