The Research on RIC-ISAR Image of Ship Target Based on High-Order Match-Phase Transform

Due to the constantly changing motion of a ship target, high order phase terms which cannot be neglected and results in bad azimuth focusing are generated. In this condition the RD algorithm is not a very effective way for ISAR imaging. In fact, the azimuth position of target scattering point can also be illustrated by the instantaneous chirp rate of received signal not just by the Doppler frequency. In this paper, a new approach is proposed, which is based on Product High-Order Matched-Phase Transform (PHMT) to estimate the value of the changing rate of chirp rate, chirp rate, central frequency and amplitude, thus the high quality range-instantaneous chirp rate (RIC) ISAR image of the object can be obtained. At last, the simulation results prove the effectiveness of the method proposed.