Wideband DOA Estimation under Clutter using MIMO Radar with Sparse Array

Direction of arrival (DOA) estimation using multiple-input multiple-output (MIMO) radar with co-located antennas under clutter environment is investigated. Considering the case where the number of radar receive antennas is limited due to practical constraint, to improve the DOA estimation performance, the antenna array is often designed to be sparse. Sparse array has been shown to work well when the target scene is sparse in the observation space. However, the presence of clutter may destroy the sparsity and thus degrade the estimation performance. To address this problem, we employ wideband signals for the sparse array. A wideband DOA estimation method based on compressive sensing after beamforming is proposed. In order to improve the DOA estimation performance, an optimization problem is formulated to jointly optimizing the sparse array antenna positions and the beamforming weights. A simplifying algorithm is presented to solve the joint optimization problem. Numerical examples are provided to demonstrate the performance of the proposed method.