Super Resolution DOA Based on Relative Motion for FMCW Automotive Radar
Wei Zhang, Ping Wang, Ningyu He, Zishu He
Abstract
Frequency modulated continuous wave (FMCW) based millimeter wave (MMW) radar systems have found widespread applications in advanced driving assistant system recently. MMW radar has clear superiority in many aspects, such as excellent range resolution, adaptability to various environments and low cost. However, its fatal weakness is the poor angular resolution which is very important in automotive radar applications. This shortcoming can be overcome by using a physically large aperture. However, achieving moderate angular resolution requires an array that is too large to be practically integrated into a vehicle. In this paper, a high resolution direction of arrival (DOA) approach is proposed by utilizing the relative motion between radar and targets, and a very large virtual aperture can be created by combining the signal vectors from multiple consecutive coherent processing intervals (CPIs). It should be pointed out that, the proposed approach is applicable for both stationary and moving targets even without motion data of vehicles. Therefore, it is completely different from the synthetic aperture radar (SAR). The effectiveness is verified by both simulation results and the measurement data. It is demonstrated that the angular resolution can be superior to 1° by a linear array consisting of only 4 elements.