TW-TOA BASED COOPERATIVE SENSOR NETWORK LOCALIZATION WITH UNKNOWN TURN-AROUND TIME

Paper in proceeding, 2013

This work aims to estimate multiple node positions in the presence of unknown turn-around times within the context of cooperative sensor network localization. In the adopted scheme, each target can communicate with a set of anchors (probably not in sufficient numbers) and a set of other targets. Two-Way Times-of-Arrival between them are measured, which includes unknown processing delays at both channel endpoints. Since finding the Maximum Likelihood Estimates (MLE) of the positions and turn-around times given those measurements poses a difficult nonconvex optimization problem, it is approximated by a Nonlinear Least Squares problem. Then, the positions and turn-around times of multipletargets are estimated jointly by solving an Euclidean Distance Matrix completion problem. Simulations show that the localization accuracy of the proposed method is good, providing an initial point that subsequently enables MLE to attain the Cram´er-Rao Lower Bound for all considered scenarios.