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Range-free Localization Based on Adaptive Anchor Selection for Wireless Sensor Networks

In order to improve the localization accuracy in wireless sensor networks (WSNs), a range-free localization algorithm based on adaptive anchor selection RF-LAAS is proposed in this paper. The adaptive anchor selection performed at sensor nodes takes into account the distance estimation error and the geometric position distribution of each anchor node. Sensor nodes first sort anchor nodes in ascending order according to the distance estimation errors. Then, the geometric dilution of precision (GDOP) metric is used to adaptively select anchor nodes with good geometric position distribution, where the GDOP threshold is determined by the anchor nodes themselves. The selected anchor nodes in each localized node are used for the localization of unknown nodes. Simulations indicate that the proposed algorithm outperforms other algorithms of interest in terms of localization accuracy in both isotropic networks and anisotropic networks.