FMCW Radar for 3-D Tracking Based on MLBI Interferometer and MDS Estimation

This article presents the implementation of a C-band frequency-modulated continuous wave (FMCW) radar system, utilizing software-defined radio (SDR) hardware and integrated with a five-element multilong-baseline interferometer (MLBI) receiver, for the detection and 3-D tracking of passive moving targets. A key aspect is the generation of a low jitter, high signal-to-noise-and-distortion ratio (SINAD) signal, which significantly enhances the radar’s performance for angle of arrival (AoA) detection and micro-Doppler signature (MDS) estimation. The high signal quality achieved enables the detection and 3-D tracking of low radar cross-sectional (RCS) targets, such as small drones, at distances up to 800 m without requiring high radar power. In addition, this work demonstrates the effectiveness of a simple phase line assignment algorithm to mitigate errors in the AoA measurement of passive moving targets even when the MLBI geometry deviates from its optimal configuration. The performance of the radar system was evaluated in an open-field test using a DJI Mavic 3, and the results highlight the significant potential of this radar concept for medium-cost 3-D tracking and MDS identification applications.