一种基于FrFT的ISAR多目标成像方法

针对逆合成孔径雷达（IsAR）同一波束内多个运动目标在距离上重叠时的成像问题，提出了一种基于分数阶傅里叶变换（FrFT）的ISAR多目标成像新算法．首先建立多目标回波模型，通过分析各目标平动多普勒历程差异，得出各目标回波在同一距离门内均可近似为一组线性调频信号的结论．然后结合FrFT和Clean思想（FrFT-Clean）对多目标回波信号中各个目标的回波分量进行分离，最后用常规算法对各个单目标分别进行成像．仿真结果验证了该方法的有效性．

A Method of ISAR Imaging of Multiple Targets Based on FrFT

Concerning for the ISAR imaging problems of multiple moving targets within the same antenna beam being overlapping over the range, a new algorithm of ISAR imaging of multiple targets was proposed, based on fractional Fourier transform （FrFT）. First, a model of multi-target echoes was established, and it was concluded that the various echoes with the same range gate could be approximated as a batch of LFM signals, through analyzing the Doppler course diversity of each target in translation. Next, the echo component of each target in multiple target echo signals could be separated by combining FrFT and Clean idea. Finally, the imaging for each single target was done by using the traditional algorithm oflSAR imaging. By simulation results the effectiveness of the proposed method was verified.