Improvement in multiple nodes positioning accuracy for wireless sensor networks based on unknown transmitted powers

摘要

In wireless sensor networks, node position is always localised by using received signal strength measurements, which owns the advantage of low cost in engineering implementations. The improvement of multiple nodes localisation accuracy is required when the transmitted powers of anchor nodes are not known. In this paper, we propose a novel localisation refinement method to improve the positioning accuracy for wireless sensor nodes. In the proposed method, we employ linear estimator to estimate the source positions along with the transmitted powers, and then use an addition of source position to improve the nodes positioning accuracy. Furthermore, we obtain the corresponding Cramer-Rao lower bound of the problem. Finally, we simulate the proposed method and testify performance improvement. The simulation result demonstrates that, under sufficiently small noise conditions, the localisation accuracy performance of the proposed method can reach to the approximate accuracy of Cramer-Rao lower bound. It is also shown that, the mean square error decreases as path loss exponent value increases with the proposed method, which is obtained by using perfect knowledge of the path loss exponent.