子场景处理的弹载前斜视SAR时域成像算法

摘要

后向投影(back-projection,BPA)算法能有效应对弹载前斜视合成孔径雷达(synthetic aperture radar,SAR)成像的两维空变问题,且无需几何投影操作,而其庞大的计算量阻碍其实时应用.针对该问题,提出一种快速时域算法,该算法通过划分场景和孔径,利用短孔径小场景内距离徙动空变可忽略的特性进行统一的波束形成,提升运算效率.分析了该算法的计算量并与快速后投影(fast back-projection,FBP)算法进行了对比,同时研究了远场假设造成的误差引入.最后通过弹载前斜视SAR成像仿真实验验证了所提算法的效率优势.%The back-projection (BP) algorithm can effectively handle the two-dimensional space-variation in missile-borne forward squint synthetic aperture radar (SAR) imaging without image projection.However,the heavy computation is an obstacle for real-time application.A fast time-domain imaging algorithm is proposed.Under the assumption that the range migration variation can be omitted in a small piece of the scene,the image scene and synthetic aperture are divided.By this procedure,the beam formation is carried out uniformly in the sub-scene,which can improve the efficiency.Meanwhile,the errors introduced by the far field assumption are also discussed.Compared with fast back-projection (FBP) algorithm,the computation load of the proposed algorithm is analysed in detail.Finally,the efficiency of the proposed method is validated by simulation results.