Joint estimation of Doppler centroid and rate for SAR with large range migration

For synthetic aperture radar (SAR) with large range migration, the estimation accuracy of Doppler rate may be poor without range migration correction (RMC), while inversely the correct RMC needs the accurate knowledge of Doppler parameters. By exploiting the statistical property of SAR range-Doppler domain signal, a novel Doppler parameter estimation method is proposed to solve the above dilemma. Free of a priori knowledge of platform motion including antenna beam pointing direction and flying velocity, the proposed method can realise pulse repetition frequency-ambiguity resolving, clutter-locking and auto-focusing both accurately and jointly. It is also robust to scene contrast. Experimental results based on real RADARSAT data are provided to demonstrate the effectiveness of the proposed method.