New Closed-Form Estimators for the Angle of Arrival and the Angular Spread of a Locally Scattered Source

We estimate the angular spread (AS) and the nominal angle of arrival (AoA) of a locally scattered source using a uniform linear array (ULA) of sensors. First, we use Taylor series expansions to transform this problem into the localization of two point sources as it has been proposed in the literature. Based on the resulting approximate form of the covariance matrix, we directly retrieve analytical expressions for the AS and the nominal AoA. Compared with earlier works, the proposed method does not require the knowledge of the angular distribution of the scattered source. Furthermore, it accurately determines the required parameters in a computationally very simple manner as illustrated by simulations.