Maximum Likelihood 3-D Near-Field Source Localization Using the EM Algorithm

In this paper, maximum likelihood estimator is proposed for passive localization of narrowband sources in the spherical coordinates (azimuth, elevation, and range). We adapt Expectation/Maximization iterative method to solve the complicated multi-parameter optimization problem appearing on the 3-D localization problem. The proposed algorithm is based on maximum likelihood criterion which employs the source signals recorded by 2-D array under near-field assumption. Expectation/Maximization algorithm decomposes the observed data into its components and then estimates the parameters of each signal component separately providing computationally efficient solution to the resulting optimization problem. Finally, the applicability and effectiveness of the proposed algorithm is illustrated by some numerical simulations.