Ship target velocity estimation with multi-transmitter GNSS-based passive radar exploiting long integration times

This work addresses the estimation of the velocity of ship targets using a passive radar system based on multiple GNSS transmitters of opportunity. The proposed approach exploits bistatic range, Doppler and Doppler-rate measurements obtained by multiple bistatic transmitter-receiver pairs. The presence of the Doppler-rate, usually neglected in conventional estimation methods, is due to the previous detection stages, which are based on Doppler rate-driven migration compensation procedures. The method is presented as a set of closed-form equations derived for a general case applicable to an arbitrary number of transmitters and it is compared to the conventional method that exploits only range and Doppler measurements. Simulated analysis verifies the effectiveness of the proposed approach and demonstrates its robustness against distributed targets. Preliminary experimental results are also provided.