双基PFA波前弯曲误差分析及校正  

Analysis and correction of the wavefront curvature error in bistatic PFA

作　　者：王昕[1] 朱岱寅[1] 毛新华[1] 朱兆达[1] 

机构地区：[1]南京航空航天大学信息科学与技术学院,南京210016

出　　处：《中国图象图形学报》2011年第7期1192-1198,共7页Journal of Image and Graphics

基　　金：航空科学基金项目(20080152004);中国博士后基金项目(20090461119);江苏省博士后科研资助计划项目(0902014C)

摘　　要：双基聚束模式合成孔径雷达(SAR)成像中的极坐标格式算法(PFA)是基于平面波前假设建立的。由于该平面波前假设在聚焦过程中引入了相位误差,双基PFA聚焦图像中会出现空变几何失真和散焦现象。因此,实际应用PFA时其有效场景聚焦范围通常受到严格限制。基于双基合成孔径雷达回波信号相位的泰勒展开式,推导双基PFA中波前弯曲误差的解析表达式。基于此表达式,分别应用1维空变滤波和插值来补偿、校正波前弯曲效应引入的散焦和几何失真现象,从而有效改善了双基PFA的聚焦范围。点目标仿真验证了该方法的有效性。The polar format algorithm （PFA） for the bistatic spotlight-mode synthetic aperture radar （SAR） imaging is based on the planar wavefront assumption. As the unrealistic planar wavefront assumption introduces phase error terms in the focusing process, there will be space-variant geometry distortion and defocusing effect in the image focused via bistatic PFA. Hence, the focused scene size when using bistatic PFA is usually restricted severely to avoid the defocusing effect. Based on the expansion of the received signal＇ s phase term in bistatic SAR, the analytical expression of the wavefront curvature error in bistatic PFA is derived in our study. Based on the expression, the space-variant filtering and interpolation operation are applied to compensate for the defocusing effect and correct the geometry distortion in the image, respectively, which extends the focused scene size of bistatic PFA effectively. Point target simulation validates the algorithm.

关 键 词：双基极坐标格式算法 波前弯曲补偿 空变滤波 

分 类 号：TN957[电子电信—信号与信息处理]