Simultaneous multi-beam space-time-Doppler coherent integration for high-speed moving target detection in passive bistatic array radar

Abstract

High-speed moving targets (HSMTs) pose challenges for passive bistatic array radar (PBAR). When HSMTs deviate from the transmit-receive beam’s irradiation region, PBAR cannot effectively receive echo energy over an extended priod, failing to balance coherent accumulation time and goniometric accuracy. A solution is to use a satellite’s wide beam and multiple adjacent narrow receiving beams from a ground-based silent array radar. However, during long-time accumulation, HSMTs’ radial and tangential velocities cause range migration (RM), pitch beam migration (PBM), azimuth beam migration (ABM), and Doppler frequency migration (DFM). These scatter HSMT echo energy, degrading Long-Time Coherent Integration (LTCI) performance. This paper proposes a simultaneous multi-beam space-time-Doppler (STD) algorithm. First, it employs a joint beam migration correction mechanism combining phase correction and cancellation to focus multi-beam energy on the beam unit at the HSMT’s terminal moment, then utilizes the Frequency Domain Dechirp Fourier Transform (FDDFT) to handle RM and DFM, and tunes the echo Doppler and modulation frequencies to the same domain to complete coherent integration, and finally achieves detection and localization of HSMTs via the multi-beam joint centroid angle measurement. Simulations verify the superiority of the proposed STD algorithm in high-speed target detection and coherent integration.