An Effective Multipath Ghost Recognition Method for Sparse MIMO Radar

Ghost targets resulting from the reflection of electromagnetic waves by stationary objects are a long-standing issue. Currently, the majority of techniques for addressing multipath ghost targets involve either prior awareness of the environment or cooperation between multiple radars, which has its drawbacks. To address the problem with a single radar, this paper proposes a multipath ghost recognition method based on the difference between direction of departure (DOD) and direction of arrival (DOA) for sparse multiple input multiple output (MIMO) radar that does not require prior building information. This method first achieves DOD and DOA estimation of the signal through minimum variance distortionless response (MVDR). Then, a grating lobe suppression method for sparse MIMO radar in multipath environments is proposed based on the distribution characteristics of DOD-DOA spectral peaks of multipath signals. In that case, the recognition of 1-order multipath is completed by using the features of two types 1-order multipath DOD and DOA being unequal. After that, the recognition accuracy of 1-order and non-combined multipath signals is improved by accumulating multiple frames. On this basis, the linear relationship among the distances corresponding to 0-order multipath, 1-order multipath and 2-order multipath, is utilized to complete the recognition of 2-order multipath signal. Finally, several experiments are carried out to verify the effectiveness of the proposed method.