Fast Realization of Maximum Likelihood Angle Estimation With Small Adaptive Uniform Linear Array

A maximum likelihood (ML) angle estimator can obtain optimal angle estimation performance. A fast implementation of ML angle estimation is developed with small adaptive uniform linear arrays (ULA). The presented method obtains the extreme points of the ML function employing real polynomial rooting, and then determines the ML solution by searching for the maximum among the local maximum values of the ML function. It can obtain the global optimal solution of the ML estimator with low computational complexity.