Abstract: Range-free positioning technology in wireless sensor networks is a challenge. It is difficult to estimate the dislances between sensor nodes which are more than one hop away in anisotropic sensor networks with holes. We introduced a range-free localization approach in anisotropic wireless sensor networks with holes,which can estimate the ranges accurately between unknown node and reference nodes. First, the algorithm estimates different average distances of one hop along the shortest path between different anchor pairs. Then some unknown node picks up the anchor pairs,whose average distance of one hop along the shortest path is larger than some threshold and the shortest path passes corresponding unknown node,as reference nodes to estimate its position. The new algorithm can filter out the anchor nodes with higher errors of estimation distances as reference nodes. Simulation results show that the localization accuracy of new algorithm is higher than previous algorithms.

Key words: Wireless sensor networks,Localization,Dynamic hop distances