Newton-type method in spectrum estimaion-based AOA estimation

For numerical optimization of the cost function of the maximum likelihood (ML) algorithm for angle-of-arrival (AOA) estimation, Newton-type method has been widely employed. In this paper, we apply the Newton-type method to the optimization of cost function for spectrum estimation-based AOA estimation algorithm of the conventional beamforming, the Capon beamfomring and the MUSIC algorithm. Explicit expressions of the first derivatives and the second derivatives of the cost functions are presented. The expressions are used for the Newton iteration to improve the accuracy of the initial estimates. The performance improvement in terms of estimation accuracy and computational burden is demonstrated using the Monte-Carlo simulations.