Velocity Vector Estimation Method in a Single Frame Using SIMO FMCW Radar

Conventional radar systems estimate target velocity primarily based on the Doppler effect, which yields only a one-dimensional radial velocity estimate. This limitation restricts overall radar performance, as only partial information about target motion can be estimated. To overcome this limitation, estimating the lateral velocity in addition to the radial velocity enables the recovery of the two-dimensional velocity vector, thereby significantly enhancing radar sensing capability. To this end, a beat signal model for a single-input multiple-output frequency-modulated continuous wave radar is derived using a second-order approximation, and the phase terms associated with lateral velocity are identified. Based on this model, a lateral velocity estimation method is proposed, in which individual point target signals are extracted and the discrete polynomial-phase transform is applied to obtain a two-dimensional lateral velocity spectrum. Furthermore, an enhanced radial velocity estimation method is developed to mitigate undesirable phase terms induced by lateral motion. Simulation results demonstrate that the proposed velocity vector estimation method can successfully estimate the velocity vectors of multiple targets. Statistical performance analysis is presented to validate the effectiveness of the proposed method under various conditions.