快速分解后向投影SAR成像的自聚焦算法研究  

Study of Autofocus Method for SAR Imagery Created by Fast Factorized Backprojection

作　　者：李浩林[1] 陈露露[1] 张磊[1] 邢孟道[1] 保铮[1] 

机构地区：[1]西安电子科技大学雷达信号处理重点实验室,西安710071

出　　处：《电子与信息学报》2014年第4期938-945,共8页Journal of Electronics & Information Technology

基　　金：国家"十二五"预研项目(51307030102)资助课题

摘　　要：SAR图像的自聚焦处理依赖图像域与距离压缩相位历程域之间的傅里叶变换对(Fourier Transform Pairs,FTP)关系。与频域算法不同,时域算法下的这种FTP关系不仅复杂,且难以获取。为了兼顾图像快速重建和自聚焦处理,该文首先对快速分解后向投影(Fast Factorized Back-Projection,FFBP)算法进行必要的改进和适当的优化处理,提出了IFFBP(Improved FFBP,IFFBP)算法,为自聚焦算法的使用奠定了基础。其次,针对数据处理的实际需求,该文提出了一种结合中等精度惯导粗补偿、嵌套相位梯度自聚焦(Phase Gradient Autofocus,PGA)精补偿的IFFBP算法处理流程。最后,通过仿真实验和实测数据处理验证该文方法的有效性。The Fourier Transform Pairs （FTP） between the image domain and its corresponding range-compressed phase history domain is critical for autofocus. Different from the frequency-domain algorithms, this requirement of FTP is both complicated and difficult to be met in the time-domain algorithms. For a swift and effective reconstruction and autofocus processing of imagery created by the time-domain algorithm, the necessary improvement and optimization in the Fast Factorized Back-Projection （FFBP） is performed, presenting an Improved FFBP （IFFBP） algorithm further. Through the pseudo-polar coordinate system, the IFFBP is able to pave the way for autofocus application. Also, in view of the practical requirements for data processing, the IFFBP uses a moderate-accuracy Inertial Measurement Unit （IMU） to achieve a coarse compensation,and combines with the Phase Gradient Autofocus （PGA） to make a fine compensation. Finally, the simulation results and the collected data sets verify and validate the proposed approach.

关 键 词：合成孔径雷达 快速分解后向投影 虚拟极坐标系 相位梯度自聚焦 运动补偿 

分 类 号：TN957.52[电子电信—信号与信息处理]