DOA estimation for closely spaced signals

High resolution direction of arrival (DOA) estimation algorithms based on the subspace decomposition received considerable attention while rarely used in the practical applications. One of the reasons is its difficulty to resolve closely spaced signals in low signal-to-noise ratio (SNR). For applications of closely spaced signals within a priori known angle range, we filter the spectrum in direction domain to improve the SNRs of signals on array sensors and reconstruct the covariance matrix with which MUSIC algorithm is applied. The improvement in the aspects of resolution and accuracy in low SNR is shown by Monte-Carlo simulations.