A Novel Airborne SAR MOCO Algorithm Based on Optimal Weighting Doppler Frequency Modulation Rate Estimation

This letter proposes a novel airborne synthetic aperture radar (SAR) motion compensation (MOCO) method based on the optimal weighting Doppler frequency modulation rate estimation. According to the traditional map-drift (MD) algorithm, the Doppler frequency modulation rate corresponding to the range units can be estimated through azimuth sub-aperture signals. The utilization rate for range units and the contributions of the strong scattering units can be improved by using the proposed optimal weighting on the signal amplitude, increasing the estimation accuracy of the Doppler frequency modulation rate. The platform motion error can be effectively estimated through fitting the Doppler frequency modulation rate and each initial slant range based on least square processing. Real-measured high-resolution airborne SAR data validate the effectiveness and feasibility of the proposed algorithm.