Improved Frequency Division Algorithm for Residual Aperture-variant Phase Errors in Synthetic Aperture Radar

In high-resolution synthetic aperture radar, the impacts of complicated motion errors on azimuth phase should be eliminated to obtain well-focused images. To this end, an improved frequency-division has been developed based on the precise angle-frequency relation. The proposed method takes into account both the cross-track and along-track motion errors and could completely compensate the residual aperture-variant motion. Moreover, this fashion could be integrated into the traditional image formation algorithms with no changes. After imaging, a paired-echo suppression method based on phase gradient autofocus with integrated notch filter, is presented. Both the simulated data and real airborne data have been applied to validate this method.