ISAR imaging of multiple targets based on FrFT-CLEAN

Inverse synthetic aperture radar (ISAR) imaging of multiple warhead targets in the same antenna beam is a big challenge when they are overlapping in the same range bin. Existing methods are usually based on single target motion compensation and they can´t get clear ISAR image of multiple targets. This paper presents a new algorithm for ISAR imaging of multiple targets based on Fractional Fourier Transform (FrFT) CLEAN method to separate signals of different targets. Firstly, signal model of multiple targets is given. Then analyzed each target has different Doppler history, the signals of a certain target in a range bin correspond to a batch of multicomponent liner frequency modulation (LFM) signals. Theoretical analysis and computer simulations show the proposed method can generate the images from multiple target echoes effectively.