Gholami, M.R.Gezici, SinanStröm, E.G.Rydström, M.2016-02-082016-02-0820110536-1486http://hdl.handle.net/11693/28355Date of Conference: 5-9 June 2011The problem of positioning an unknown target is studied for a cooperative wireless sensor network using hybrid two-way time-of-arrival and time-difference-of-arrival measurements. A maximum likelihood estimator (MLE) can be employed to solve the problem. Due to the non-linear nature of the cost function in the MLE, a numerical method, e.g., an iterative search algorithm with a good initial point, should be taken to accurately estimate the target. To avoid drawbacks in a numerical method, we instead linearize the measurements and obtain a new two-step estimator that has a closed-form solution in each step. Simulation results confirm that the proposed linear estimator can attain Cramer-Rao lower bound for sufficiently high SNR. © 2011 IEEE.EnglishCooperative positioninglinear estimatorwireless sensor networksClosed form solutionsCooperative positioningCooperative wireless networksCramer Rao lower boundHigh SNRInitial pointLinear estimatorsMaximum likelihood estimatorNon-linearPositioning algorithmsSearch AlgorithmsSimulation resultTime-difference-of-arrivalTime-of-arrivalWireless sensorAlgorithmsCramer-Rao boundsEstimationMaximum likelihood estimationNumerical methodsSensorsWireless sensor networksConference Paper10.1109/icc.2011.5962647