一种适用于编队目标的ISAR成像处理实现方法

An Implementation Method of ISAR Imaging for Multiple Targets in Formation

在对编队目标的ISAR成像中,由于目标之间的间距很小,各目标回波常常在距离域和多普勒域都有重叠,难以进行多目标回波分离和分别成像.本文提出一种适用于编队目标的ISAR成像实现方法.对多目标回波统一进行径向加速度补偿和Keystone变换,完成多目标的距离对齐.在横向作多普勒分辨时,考虑各目标散射点子回波可近似为线性调频信号,引入修正离散Chirp-Fourier变换,并结合CLEAN技术,同时得到多目标的距离-多普勒像.仿真实验结果证明了该方法的有效性.

When multiple targets in formation are in the observation region, the return signals from these targets may be overlapped both in the range and Doppler domain. Thus, it is difficult to separate these targets from each other, and each individual target cannot be clearly.imaged. A new implementation method of ISAR imaging is proposed for multiple targets in formation. After radial acceleration compensation and Keystone transformation are performed, range alignment is accomplished for all moving targets. When multiple targets are moving smoothly, the Doppler variation of subechoes from scatterers can be approximated as a first-order polynomial. Therefore, the modified Chirp-Fourier transform combined with the CLEAN technique is applied to each range cell to obtain the cross-range profiles of multiple targets simultaneously. The imaging results obtained by using simulated data show the effectiveness of the proposed method.