在对复杂运动目标进行逆合成孔径雷达成像时,由于转动矢量随时间而变化,回波信号中会引入一个与散射点位置有关的相位误差,无法用通常的相位补偿方法进行校正,应用距离-多普勒算法获得的ISAR(Inverse Synthetic Aperture Radar)像会变得模糊.本文分析了目标转动矢量变化使得ISAR像模糊的内在原因,给出了目标三维转动状态下的ISAR信号形式,并基于散射点信号的特点提出了一种复杂运动目标的ISAR成像算法.该算法不仅适用于转动矢量方向不变的非均匀转动目标,而且对于转动矢量方向缓慢变化的目标,算法仍然能够有效地提高ISAR成像的质量.仿真试验结果表明了该算法的有效性.

When inverse synthetic aperture radar (ISAR) imaging the target with complex motion,the time-varying rotation vector will induce phase errors depending on the scatter positions.Such errors can not be eliminated by traditional motion compensation algorithm,and the radar images obtained by the conventional range Doppler (RD) algorithm will smear.The intrinsic image-smearing reasons are analyzed when the rotation vector varies with time,and the radar received signal expression in presence of three dimension rotation is determined.An ISAR imaging algorithm based on the property of the scatter signals is proposed for the complex motion targets.This algorithm is effective for imaging the target which has constant rotation orientation but time-varying rotation velocity.Furthermore,when the rotation orientation varies slowly,the algorithm can also effectively improve the quality of ISAR images.Finally,several simulation results demonstrate the performance of the algorithm.