Direction-of-arrival estimation in partially calibrated subarray-based MIMO radar

The problem of direction-of-arrival (DOA) estimation in partially calibrated multi-input multi-output (MIMO) radar composed of multiple subarrays is studied. We assume that each subarray is calibrated well, so that the steering vectors of all subarrays are exactly known. However, the intersubarray parameters are completely/partly unknown. The proposed method first obtains a set of initial DOA results by employing a rotational invariance property between two sets of received data associated with the two calibrated antennas within the first subarray, and then more accurate DOA estimation is obtained by using the rank reduced estimator (RARE) through a local searching algorithm. We also derive the corresponding stochastic CramérRao bound (CRB) to which we compare the performance of the proposed estimator.