A Novel Method for Refocusing Maritime Targets in SAR Images

Synthetic Aperture Radar (SAR) imaging of maritime targets is possible to be defocused or blurred due to targets' sailing movement and complex motions caused by sea wave. To refocus maritime moving targets, Inverse Synthetic Aperture Radar (ISAR) based sub-aperture technology is often used. However, the quality and resolution of refocused images decrement is likely to happen under this condition. To obtain high-resolution and high-quality images via short apertures, a novel ISAR-based method is proposed utilizing the joint optimization of all sub-aperture images. Two priors, the low rank property among all sub-aperture images as well as the target sparsity in one sub-aperture image, are introduced in this paper. The effectiveness of the proposed method is verified on Gaofeng-3 spotlight SAR images of maritime targets.