Gholami, M.R.Gezici, SinanStröm, E.G.Rydström, M.2016-02-082016-02-082011http://hdl.handle.net/11693/28347Date of Conference: 26-29 June 2011This paper addresses the problem of single node positioning in cooperative network using hybrid two-way time-of-arrival and time-difference-of-arrival where, the turn-around time at the target node is unknown. Considering the turn-around time as a nuisance parameter, the derived maximum likelihood estimator (MLE) brings a difficult global optimization problem due to local minima in the cost function of the MLE. To avoid drawbacks in solving the MLE, we obtain a linear two-step estimator using non-linear pre-processing which is algebraic and closed-form in each step. To compare different methods, Cramér-Rao lower bound (CRLB) is derived. Simulation results confirm that the proposed linear estimator attains the CRLB for sufficiently high signal-to-noise ratios. © 2011 IEEE.EnglishCooperative positioningGlobal optimization problemsHigh signal-to-noise ratioLinear estimatorsLocal minimumsLower boundsMaximum likelihood estimatorNon-linearNuisance parameterPositioning algorithmsPre-processingSimulation resultTarget nodesTime-difference-of-arrivalTime-of-arrivalEstimationFading (radio)Global optimizationMaximum likelihood estimationSignal processingSignal to noise ratioWireless telecommunication systemsWireless sensor networksConference Paper10.1109/SPAWC.2011.5990386