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Improved Position Estimation Using Hybrid TW-TOA and TDOA in Cooperative Networks

Mohammad Reza Gholami (Institutionen för signaler och system, Kommunikationssystem) ; Gezici Sinan ; Erik G. Ström (Institutionen för signaler och system, Kommunikationssystem)
IEEE Transactions on Signal Processing (1053-587X). Vol. 60 (2012), 7, p. 3770-3785.
[Artikel, refereegranskad vetenskaplig]

This paper addresses the problem of positioning multiple target nodes in a cooperative wireless sensor network in the presence of unknown turn-around times. In this type of cooperative networks, two different reference sensors, namely, primary and secondary nodes, measure two-way time-of-arrival (TW-TOA) and time-difference-of-arrival (TDOA), respectively. Motivated by the role of secondary nodes, we extend the role of target nodes such that they can be considered as pseudo secondary nodes. By modeling turn-around times as nuisance parameters, we derive a maximum likelihood estimator (MLE) that poses a difficult global optimization problem due to its nonconvex objective function. To avoid drawbacks in solving the MLE, we linearize the measurements using two different techniques, namely, nonlinear processing and first-order Taylor series, and obtain linear models based on unknown parameters. The proposed linear estimator is implemented in three steps. In the first step, a coarse position estimate is obtained for each target node, and it is refined through steps two and three. To evaluate the performance of different methods, we derive the Cramer-Rao lower bound (CRLB). Simulation results show that the cooperation technique provides considerable improvements in positioning accuracy compared to the noncooperative scenario, especially for low signal-to-noise-ratios.

Nyckelord: Cooperative positioning, Cramer-Rao lower bound (CRLB), linear estimator, maximum-likelihood estimator (MLE), time-of-arrival (TOA), time-difference-of-arrival (TDOA), two-way time-of-arrival (TW-TOA), wireless sensor network

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Denna post skapades 2012-03-28. Senast ändrad 2012-08-14.
CPL Pubid: 156275


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Institutioner (Chalmers)

Institutionen för signaler och system, Kommunikationssystem (1900-2017)


Informations- och kommunikationsteknik

Chalmers infrastruktur

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Wireless Sensor Network Positioning Techniques