Improved Position Estimation Using Hybrid TW-TOA and TDOA in Cooperative Networks
Journal article, 2012

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.

Cooperative positioning

maximum-likelihood estimator (MLE)

time-of-arrival (TOA)

linear estimator

time-difference-of-arrival (TDOA)

two-way time-of-arrival (TW-TOA)

Cramer-Rao lower bound (CRLB)

wireless sensor network

Author

Mohammad Reza Gholami

Chalmers, Signals and Systems, Communication and Antenna Systems, Communication Systems

Sinan Gezici

Bilkent Universitesi

Erik Ström

Chalmers, Signals and Systems, Communication and Antenna Systems, Communication Systems

IEEE Transactions on Signal Processing

1053-587X (ISSN)

Vol. 60 7 3770-3785 6183529

Areas of Advance

Information and Communication Technology

Subject Categories

Telecommunications

Signal Processing

DOI

10.1109/TSP.2012.2194705

More information

Created

10/6/2017