A Multiple Baseline Interferometric Radar for Multiple Target Angular Velocity Measurement

We present a novel technique for directly estimating the angular velocities of multiple targets using multi-baseline millimeter-wave interferometric radar to significantly reduce nonlinear signal distortion caused when multiple targets are present. We show that through the multiplication of the normalized instantaneous frequency measurements across different baselines, nonlinear intermodulation products resulting from dual-antenna interferometric angular velocity measurements can be mitigated, producing only the terms corresponding to the angular velocity of the targets in the scene. To validate this, simulations were performed demonstrating the close agreement between the proposed method and an ideal correlation (without intermodulation distortion). Near-field errors resulting from far-field approximations are analyzed. Finally, experimental results of a three-antenna, three-baseline 38-GHz interferometric radar are presented that demonstrate the recovery of the motion of two oscillating pendulums of differing angular frequencies.