适用于任意雷达航迹的双基PFA波前弯曲误差补偿  

Wavefront Curvature Compensation in Bistatic Polar Format Algorithm Under Arbitrary Flight Path

作　　者：何成宇[1] 毛新华[1] 

机构地区：[1]南京航空航天大学电子信息工程学院,南京210016

出　　处：《数据采集与处理》2013年第4期485-490,共6页Journal of Data Acquisition and Processing

基　　金：江苏高校优势学科建设工程(苏政办发2011 6号)资助项目;国家自然科学基金(61071165)资助项目;教育部博士点基金(20070280753)资助项目;中央高校基本科研业务费(NS2012097)资助项目

摘　　要：双基极坐标格式算法(Polar format algorithm,PFA)由于算法简洁、且能适用于任意双基配置,但跟单基PFA类似,双基PFA算法受波前弯曲误差影响,其有效成像场景范围受到一定限制。采用图像域的空变后滤波处理可以有效补偿波前弯曲误差,但该方法基于雷达平台线性运动假设,无法满足任意航迹条件下的波前弯曲误差补偿要求。本文提出了一种改进的空变后滤波处理方法,通过对相位历史域的波前弯曲误差函数作与双基PFA成像相同的极坐标格式转换处理,得到波前弯曲误差在两维空间频域的精确表示,从而构造了空变后滤波处理所需的滤波器。仿真结果表明该算法能够精确补偿雷达任意航迹条件下双基PFA波前弯曲误差,显著提高了双基PFA有效成像场景范围。本文算法在双基合成孔径雷达(Synthetic aperture radar,SAR)大场景超高分辨率成像时具有很大的应用前景。Bistatic polar format algorithm （PFA） is simple and can be applied to any bistatic configuration. But as the monostatic polar format algorithm, the space-variant defocus effect introduced by wavefront curvature in bistatic polar format algorithm imagery limits its maximal focused scene size. The method of space-variant post processing in image domain can compen- sate wavefront curvature error effectively. However this approach is based on the assumption that radar platform follows an expected linear trajectory. It still cannot meet the required preci- sion when imaging is under arbitrary radar flight path. An improved space-variant post pro- cessing method for wavefront curvature compensation is proposed. The method computes wavefront curvature error in original phase history domain and transforms it into two dimen- sional spatial frequency domain by bistatic polar format transformation used in image forma- tion. Thus, a filter needed in space-variant post processing is acquired. Simulation experiments show that the new algorithm can accurately compensate the wavefront curvature effect under arbitrary radar flight path and improve focused scene size. The method has a good application prospect in the bistatic SAR ultra high resolution imaging signal processing in large scene.

关 键 词：双基合成孔径雷达 极坐标格式算法 波前弯曲补偿 任意航迹 

分 类 号：TN953[电子电信—信号与信息处理]