前视成像中Keystone变换残余距离走动的频域补偿

Frequency domain compensation of the residual range walk after Keystone transform in forward-looking imaging

空载平台采用扫描模式进行前视成像时,平台运动会导致目标积累时间内出现距离走动和多普勒模糊.Keystone变换可以补偿前视扫描时间内目标的跨距离单元走动,但是在发生多普勒模糊的情况下,Keystone校正的模糊数补偿可能引入速度残差,导致目标定位误差.针对此,本文研究了空载平台前视成像的Keystone校正方法,提出一种在频域补偿Keystone变换残余距离走动的方法,即基于速度残差进行距离走动校正降低残余包络误差,实现目标的聚焦与准确定位.基于单脉冲前视成像的理论分析与仿真实验验证了所提出算法的有效性.

For the forward-looking imaging of airborne platform,the platform motion will lead to range walk and Doppler ambiguity during the accumulation time.The Keystone transform can compensate the cross-range unit walk of the target during the forward-looking scanning time in the radar,however,in the case of Doppler ambiguity,the ambiguity number compensation of Keystone correction may introduce residual velocity and lead to target localization errors.We study the Keystone correction method for the forward-looking imaging of airborne platform and propose a method to compensate the residual range walk introduced by the Keystone transform,so as to improve the focus and accurate positioning of the target.The theoretical analysis and simulation experiments verify the effectiveness of the proposed algorithm.