ISAR motion compensation based on a new Doppler parameters estimation procedure

The work addresses the problem of compensating the distortion effects induced by the translational motion of moving targets in Inverse Synthetic Aperture Radar (ISAR) imaging systems. The ISAR motion compensation is the most crucial step in the Autofocusing ISAR technique; this task is typically solved by implementing exhaustive search algorithms by adopting proper functionals based f.i. on image entropy or image contrast. In this work, we discuss an innovative and fast motion compensation procedure that is based on the estimation of two Doppler key Parameters: the Doppler Centroid and the Doppler Rate, which are related to the target motion parameters. The effectiveness of the proposed method is tested on real data acquired by a static Frequency Modulated Continuous Wave radar with an azimuth wide beamwidth; the radar is installed near the inner harbor of La Spezia (Italy) and it owned to the Centre for Maritime Research and Experimentation of the North Atlantic Treaty Organization (CMRE-NATO).