Fast Single-Snapshot DOA Estimation of Coherent Sources for Distributed mmWave Radar System

This brief considers the Direction of Arrival (DOA) estimation for Distributed mmWave Radar System (DmmWRS) in the presence of coherent sources and a single snapshot. To this end, the large virtual aperture is firstly derived assuming that DmmWRS works in time-sharing mode. Then, a Fast Local Iterative Search Algorithm (FLISA) resorting to Iterative Adaptive Approach (IAA) and prior DOA information obtained by a single radar, is developed to accurately estimate DOA within a small azimuth region of interest. Finally, numerical simulations and actual measurements show the superiority of the proposed approach than some counterparts providing better angle measurement performance, more importantly, FLISA has lower computational complexity and faster convergence than IAA.