Multi-transmitter ship target detection technique with GNSS-based passive radar

The exploitation of the Global Navigation Satellite Systems (GNSS) as transmitters of opportunity in passive radar systems for maritime surveillance is particularly attractive because of the main advantages consisting in a global coverage (even in open sea) and in the availability of multiple sources (different satellites and constellations). The main drawback stays in the restricted power budget provided by navigation satellites. This characteristic makes necessary to conceive, define and develop detection techniques able to overcome such limitation. To this aim this work proposes a range-Doppler domain processing technique able to integrate over long time intervals the returns from a moving target illuminated by multiple GNSS transmitters. Several examples are shown to demonstrate the effectiveness of the proposed approach.