Three Dimensional Velocity Measurement Using a Dual Axis Millimeter-Wave Interferometric Radar

Abstract: In this work, a method for directly measuring target velocity in three dimensions using a dual axis correlation interferometric radar is presented. Recent advances have shown that the measurement of a target's angular velocity is possible by correlating the signals measured at spatially diverse aperture locations. By utilizing multiple orthogonal baselines and using conventional Doppler velocity methods to obtain radial velocity, a full three-dimensional velocity vector can be obtained using only three receive antennas and a single transmitter, without the need for tracking. A $\text{41.8 GHz}$ dual axis interferometric radar with a $7.26\lambda$ antenna baseline is presented along with measurements of a target moving parallel to the plane of the radar array, and of a target moving with components of both radial and tangential velocity. These experiments achieved total velocity root-mean-square errors of $\text{41.01 mm}\cdot\text{s}^{-1}$ ($10.5\%$) for a target moving along a plane parallel to the array, and $\text{45.07 mm}\cdot\text{s}^{-1}$ ($13.5\%$) for a target moving with components of radial and tangential motion relative to the array; estimated trajectory angle RMSEs of $10.42^\circ$ and $5.11^\circ$ were achieved for each experiment respectively.