Single-Snapshot DOA Estimation in MIMO Radar Using Fast Iterative Interpolated Beamforming

In this work we propose a computationally efficient beamforming based algorithm for direction of arrival (DOA) estimation of multiple sources in Multiple-Input-Multiple-Output radar. It has long been held that, in the case of multiple sources, subspace methods such as Root MUSIC and ESPRIT are necessary to separate close sources and deliver unbiased estimates. However, in addition to the heavy computational burden, these methods require spatial smoothing in the single snapshot case and are unable to extract correlated sources. In contrast, our proposed algorithm recruits the recently proposed and computationally efficient Fast Iterative Interpolated Beam-former (FIIB) to achieve accurate DOA estimation without the need for spatial smoothing. We show how the FIIB can be applied to the MIMO DOA problem both in the overlapped and non-overlapped virtual array cases. We also demonstrate that the proposed estimator outperforms the Root-MUSIC algorithm in both cases.