Inverse synthetic aperture radar imaging of targets with complex motion based on cubic Chirplet decomposition

High resolution inverse synthetic aperture radar (ISAR) imaging of targets with complex motion is a main topic in the radar imaging domain. In fact, the traditional range-Doppler algorithm is not appropriate to generate a focused ISAR images because of the time-varying Doppler shifts caused by the target´s complex motion. In this study, the azimuth received signal is modelled as multi-component amplitude-modulated and frequency-modulated (AM-FM) signal, and a novel algorithm for the cubic Chirplet decomposition based on generalised cubic phase function is proposed to investigate the AM-FM signal analytically. Then, the corresponding ISAR imaging algorithm associated with the range-instantaneous-Doppler technique is proposed. Results of simulated and real data demonstrate the effectiveness of the presented algorithm.