%0 Journal Article %T Anchor-Free Localization Method for Mobile Targets in Coal Mine Wireless Sensor Networks %A Zhongmin Pei %A Zhidong Deng %A Shuo Xu %A Xiao Xu %J Sensors %D 2009 %I MDPI AG %R 10.3390/s90402836 %X Severe natural conditions and complex terrain make it difficult to apply precise localization in underground mines. In this paper, an anchor-free localization method for mobile targets is proposed based on non-metric multi-dimensional scaling (Multi-dimensional Scaling: MDS) and rank sequence. Firstly, a coal mine wireless sensor network is constructed in underground mines based on the ZigBee technology. Then a non-metric MDS algorithm is imported to estimate the reference nodesĄŻ location. Finally, an improved sequence-based localization algorithm is presented to complete precise localization for mobile targets. The proposed method is tested through simulations with 100 nodes, outdoor experiments with 15 ZigBee physical nodes, and the experiments in the mine gas explosion laboratory with 12 ZigBee nodes. Experimental results show that our method has better localization accuracy and is more robust in underground mines. %K Wireless sensor networks %K Multi-dimensional scaling %K Received signal strength %K Rank sequence %U http://www.mdpi.com/1424-8220/9/4/2836