Moving Target Imaging via TR-SOKT for SAR With Maneuvering Trajectory

Abstract

Maneuvers not only provide flexibility for synthetic aperture radar ground moving target imaging (SAR-GMTIm), but also means more complex echo characteristics, especially in high-resolution situations. This letter systematically analyzes and establishes an imaging model for SAR-GMTIm with maneuvering trajectory, revealing the high-order range cell migration, Doppler centroid ambiguity, and other issues. Based on above issues, an imaging method based on time reversal-second-order keystone transform (TR-SOKT) is proposed, which first corrects range walk migration (RWM) through time reversal (TR), then range curve migration (RCM) is corrected by SOKT, and azimuth residual phase is estimated and compensated by high-order ambiguity function (HAF). The proposed method is not affected by Doppler centroid ambiguity, making it suitable for target with various velocities. Additionally, parameter search is not performed during migration correction, resulting in low computational burden. The performance of the proposed method is verified by simulation and real data experiments.