Cognitive Target Tracking via Angle-Range-Doppler Estimation With Transmit Subaperturing FDA Radar

Cognitive radar is an intelligent active sensing technique, which can learn the interactions between radar and its surrounding environment and adaptively adjust the transmit waveforms or parameters for improved performance. In this paper, we propose a cognitive target tracking scheme via angle-range-Doppler estimation with transmit subaperturing frequency diverse array (TS-FDA) radar. FDA is an emerging array technique that employs a small frequency increment across its array elements to produce a range-angle-dependent beampattern, which provides promising applications for joint angle-range-Doppler estimation of targets. In order to jointly enjoy the advantages of FDA localization in angle-range dimension and phased-array in coherent gain, we divide the FDA elements into multiple subarrays and propose two optimization criteria, respectively, based on signal-to-noise ratio and Cramér-Rao bound, to adaptively design the transmit weight matrix according to the prior knowledge extracted from the cognitive observation data at each transmission updating for improved tracking performance. All proposed approaches are verified by numerical results.