Synthetic Interferometry Exploiting Radar Motions

The instantaneous velocity of any moving object can be decomposed into two orthogonal components with reference to the observing radar, namely, radial velocity along the radar line of sight (LoS) and transversal velocity perpendicular to the LoS. It has been shown that the measurement of transversal velocity can significantly improve the performance of both radar target tracking and classification. Furthermore, the precision of transversal velocity estimation is proportional to the baseline length using static interferometry. However, the large baseline is impractical in applications, such as automotive radar with restrictions on the packaging size. This letter proposes synthetic interferometry exploiting radar motions. A large virtual baseline can be synthesized by moving the side-looking radar and synchronizing the received signals at two locations, thus improving the accuracy of transversal velocity measurement. We derive the conditions of time synchronization for successful interferometry in terms of the maximum moving distance and the maximum observation time. Both simulations and experiments have been conducted to validate the feasibility and effectiveness of the proposed synthetic interferometry.