基于空变运动补偿的斜视SAR成像技术

Image Formation for Squint Synthetic ApertureRadar Based on Space-variant Compensation

摘要:

机载和弹载合成孔径雷达(synthetic aperture radar,SAR)成像时,因运动误差的空变性(距离、方位、孔径)导致修正成像补偿函数非常困难。针对该问题,在不影响标准处理的基础上,以统一运动补偿和成像处理为出发点,首先在距离向进行基于线性变标的距离包络校正处理,实现对线性运动误差空变分量的补偿;其次引入基于精确多普勒-斜视角的频域分割算法,通过精确计算多普勒-瞬时斜视角的解析式,完成孔径空变分量的补偿;最后通过回波数据仿真证明了所提算法的有效性。该方法在原始回波域进行补偿,传统成像方法不需要修改就能与之结合,提高了算法泛化性。

Abstract:

During the image formation process of airborne and missile-borne syntheticaperture radar (SAR), it is difficult to revise the phase-compensating function for the spacevariant characteristics (i.e. range, aztimuth and aperture) of motion errros. As for thisproblem, the starting point is to incorporate the motion compensation and image formationunder no changes of standard procedures. First, the range envelope correction with chirpscaling is performed in order to remove the linear components in motion errors.Second, theprecise frequency division (PFD) based on precise azimuth time-Doppler mapping is appliedto correct the aperture-avriant components. Third, the simulation experiments are carriedout to validate the effectiveness. The proposed method finishes all procedures in raw-echodomain, helps to combine it with the traditional imaging algorithms without any changes andimproves its generalization performance.