Statistical analysis of subspace-based method for direction estimation without eigendecomposition

A computationally simple direction-of-arrival (DOA) estimation method with good statistical performance is attractive in many practical applications of array processing. This paper studies the statistical properties of a new computationally efficient subspace-based method without cigendecomposition (SUMWE) for estimating the directions of narrowband signals impinging on a uniform linear array (ULA), where he asymptotic mean-squared-error (MSE) expression of the estimation error is derived. The theoretical analysis is substantiated through numerical examples, and it is shown that the SUMWE can resolve closely spaced coherent signals better with a smaller number of snapshots and at lower signal-to-noise ratio (SNR).