Hybrid SAR/ISAR imaging of ship targets based on parameter estimation

摘要

Typical Synthetic Aperture Radar (SAR) imaging deals with static targets. This means that moving targets appear blurred in SAR images. Difficulties in imaging are especially noticeable for moving ship targets at sea due to sea waves and each targets individual movement characteristics. Presently, there are no satisfactory results for hybrid SAR and Inverse Synthetic Aperture Radar (ISAR) imaging of multiple ship targets. Focussing on this problem, this letter proposes an improved airborne hybrid SAR/ISAR imaging algorithm based on parameter estimation. In this algorithm, Doppler parameters are estimated by using Radon-Wigner transform (RWT) at first. Then, we improve the traditional data extraction method, in which multi-objective problems are solved through data pre-processing and original characteristics of the data are preserved to the maximum extent. Three representative types of the ship data are selected in this letter and we extract them. Finally, effective ISAR motion compensation methods are adopted for the purpose of gaining focus results. The final images verify a strong feasibility of the proposed algorithm and it provides a good idea for moving ship targets imaging.