A high-resolution ground moving target imaging method based on motion compensation

Imaging and parameter estimation of moving targets in airborne single-antenna high-resolution synthetic aperture radar (SAR) system is affected by motion errors, which cause defocusing and dislocation of moving targets. Motion errors derive from platform flight deviation and unknown target velocity and estimating all motion errors once is difficult because both aspects influence each other, especially in unmanned aerial vehicle (UAV) systems. We find that the platform flight deviation has the same effect on stationary targets and moving ones. Exploiting this similarity, we propose a novel ground moving target motion compensation method. Platform flight errors are extracted from stationary targets by autofocus algorithms and compensated for moving targets. And then Hough transform (HT) and Map-Drift (MD) technique is used to estimate the radial velocity and the along-track velocity, and range cell migration correction (RCMC) is completed by estimated velocities. Furthermore, PGA technique is adopted to estimate and correct residual phase errors. The effectiveness of the proposed algorithm is validated by the real data.