机载双站SAR成像区分块分析

Analysis on Imaging Region Blocking of Airborne Bistatic SAR

机载双站SAR的回波数据具有距离向空变性或距离-方位向二维空变性,需要对观测场景进行分块成像。本文从机载双站SAR的斜距历程出发,借助于载机轨迹解耦合公式,推导了观测场景中任一点目标的距离走动和距离弯曲公式。根据距离徙动校正后的残余距离徙动与二阶相位误差研究了机载双站SAR的成像区分块准则。基于分块准则仿真得到了各种构型机载双站SAR的成像区分块结果,分析了双站结构参数与系统参数对成像区的影响,为机载双站SAR宽场景成像时成像区分块提供了理论指导。

The echo data of airborne bistatic SAR has range space variance or range-azimuth space variance,so it is necessary to perform block imaging in airborne bistatic SAR focusing.Based on the slant range of airborne bistatic SAR,the range walk and range cure formulas of arbitrary point target in the observing scene are derived with the track decoupling formulas.After performing the range cell migration （RCM）correction,imaging region blocking rules are derived with the residual range cell migration and quadratic phase error （QPE）.Then imaging region blocking results of airborne bistatic SAR in various configuration are tested with the numerical simulations,moreover,influences of geometry parameters and system parameters on imaging region are also analyzed,and they provide theoretical guidance to imaging region blocking in airborne bistatic SAR wide scene focusing.