Approach for high-resolution inverse synthetic aperture radar imaging of ship target with complex motion

High-resolution inverse synthetic aperture radar (ISAR) imaging of ship target has attracted the attention of many scholars all around the world. For the complex motion of the ship, the Doppler frequency shifts of the scatterers are actually time-varying, and the received signals in a range bin can be characterised as multi-component amplitude-modulated and frequency-modulated (AM-FM) signals. In this study, the AM-FM signals are approximated as a weighted sum of multiple Chirplets, and a novel approach for high-resolution ISAR imaging of ship target based on the product cubic phase function (PCPF) for Chirplet decomposition is proposed. The PCPF algorithm can reduce the cross-terms between different Chirplet components, and combined with the range-instantaneous-Doppler technique, the high-resolution instantaneous ISAR images can be obtained. Results of simulated and real data demonstrate the effectiveness of the method proposed.