分布式星载SAR波束同步误差对合成双程天线方向图的影响分析

摘要

The antenna pattern error is the main error of effecting target radiometric properties. Distributed spa-cebome SAR operates with the transmitter and receiver is spatially separated. The synthesis antenna pattern is multiplied by the receiver and transmitter antenna pattern. Therefore, the distributed spacebome SAR beam synchronization error will inevitably affect the synthetic attenna pattern. Based on distributed SAR beam synchronization, the receiver beam scanning error and beam pointing synchronization error influence on the antenna pattern are analyzed, and showed that the former has smaller effect on the antenna pattern while the later has greater. It's necessary for calibration on beam synchronization to improve the synthetic antenna pattern precision.%天线方向图不确定性是影响SAR图像辐射特性的主要误差源之一,在SAR辐射定标处理中必须对其进行校正.由于分布武星载SAR系统的收发分置,其双程天线方向图是主星发射天线和辅星接收天线方向图的合成.因此,分布武星载SAR波束同步误差不可避免地会影响合成天线方向图.以分布式星载SAR波束同步原理出发,分析了其影响机理,并定量分析了辅星波束扫描和主辅星波束指向误差对合成天线方向图的影响程度.通过分析表明前者对合成天线方向图的影响较小,而后者的影响较大;并由此指出分布式SAR辐射定标需要对波束指向进行定标来提高合成天线方向图精度.