基于运动补偿的机载MIMO-SAR高分辨成像算法

机载多发多收合成孔径雷达(MIMO-SAR)可以实现高分辨成像,但不可避免的存在运动误差补偿的问题。对多子带并发的机载MIMO-SAR系统进行研究,首先建立并分析了MIMO-SAR运动误差模型;然后提出了一种扩展的MIMO-SAR运动补偿距离徙动算法(RMA),通过改进的Stolt映射将距离徙动校正与方位向聚焦分开,并结合两步运动补偿技术对MIMO-SAR回波数据的运动误差进行校正,消除了运动误差带来的影响;最后在空频域对各子带信号进行带宽合成实现了距离向高分辨。用该算法对散射点目标和面目标进行了成像仿真,验证了其在处理带有运动误差的MIMO-SAR回波数据中的有效性。

An Imaging Algorithm of High Resolution Airborne MIMO-SAR Based on Motion Compensation

Airborne Multiple-Input Multiple-out (MIMO) SAR system can be used for achieving the image with high resolution, but the inevitable problem of motion compensation must be solved. The MIMO-SAR system with several sub-bands is studied here. Firstly, a model of motion error for MIMO-SAR system is established and a detailed analysis of it is presented. Then an extended MIMO-SAR Range Migration Algorithm (RMA) integrating with motion compensation is proposed. Range Cell Migration Correction (RCMC) and azimuth focus are separated by improved Stolt-mapping, and the motion error is corrected through two steps of compensation. Finally, sub-bands are combined into a whole band in spatial-frequency domain to obtain a high range resolution. Imaging simulations for point-targets and plane-targets with this algorithm are performed to verify the validity of such algorithm.