Distributed localization of a non-cooperative RF target in NLOS environments

We propose a novel distributed generalized expectation maximization (EM) method for non-cooperative target localization using a wireless sensor network. We consider the scenario where few or no sensors receive line-of-sight signals from the target. Each sensor is able to measure the time difference of arrival of the target´s signal with respect to a reference node, as well as the angle of arrival of the target´s signal. We show that our distributed algorithm converges, and simulation results suggest that our method achieves an accuracy close to the centralized EM algorithm. We apply the distributed EM algorithm to a set of experimental measurements, which confirm that the algorithm is able to localize a RF target in a realistic non-line-of-sight scenario.