Passive radar imagery of ship targets by using navigation satellites transmitters of opportunity

This paper considers the possibility to extract features of vessels at sea with a GNSS-based passive radar system. To this purpose, a passive imaging mode has been defined to form bistatic ISAR images of the detected ship. Then, proper range and cross-range scaling factors have been derived, so that relevant features of the target such as its length can be obtained, potentially enabling target recognition procedures. Experimental results obtained with Galileo satellites demonstrate the effective possibility of the proposed approach to extract relevant features of ship targets of interest, thus providing advanced capabilities to the GNSS-based radar for maritime surveillance applications.