Exploitation of single-channel space-borne SAR data for ship targets imaging and motion parameters estimation

Nowadays, space-borne Synthetic Aperture Radar (SAR) systems can provide images with very high-resolution, representing a formidable tool for maritime surveillance applications. Nevertheless, ship targets usually appear defocused in level-1 SAR images, due to their motion. Ship target refocusing can be achieved via Inverse SAR (ISAR) techniques, and a number of autofocus approaches have been proposed and tested in the past. However, the estimation of the full ship’s dynamic (translation and rotation), is a strategic information, also providing the possibility to scale the images in the uniform range-cross-range plane. In this work, the effectiveness of suitable single-channel ISAR techniques at estimating the ship velocity and at correctly scaling the images is assessed by means of Cosmo-SkyMed (CSK) data exploiting the Automatic Identification System (AIS) information as the reference ground truth.