Multi-weak targets detection and measurement from range-Doppler maps in GNSS-based passive bistatic radar

This paper explores the GNSS satellite system as illumination in passive radar for maneuvering target detection. The main difficulty of this technology is the limited arrival power from navigation satellites. To address this, a long-time integration algorithm for multi-weak targets detection is proposed. It begins with the segmented signal model to obtain the range-compressed data, followed by the second-keystone transform to correct the intra-frame quadratic range migration. Then, a multi-target motion parameter estimation method based on the modified variational Bayesian framework is employed on the azimuth signal. Lastly, a proper compensation strategy is applied to align the targets’ positions in all integrated maps. It estimates the multiple targets’ motion measurements from the bistatic range-Doppler maps accurately, and compensates for the complicated range and Doppler migrations to improve the detection capability. This technique is validated through theoretical analysis with simulations, as well as experiments. Both simulated and real-measured data experiments prove the remarkable multi-weak targets detection and measurement performance than the existing methods.