Refocusing of ship signatures and Azimuth speed estimation based on FRFT and SAR SLC imagery

This paper considers the impact of dynamical targets on SAR imagery, when processed with stationary based techniques. We propose to employ the Fractional Fourier Transform as a tool for estimating the residual Doppler rate corresponding to moving vessels. Hence, the defocusing effect can be corrected and the associated azimuthal velocity can be estimated. The capabilities of the proposed methodology are illustrated with moving vessels extracted from Radarsat-2 Multilook Fine images and AIS data flows as ground truth.