关键词: 无线传感器网络, Grid-Scan算法, 定位精度, 虚拟锚节点, 可定位阈值, 极大似然法

Abstract: Concerning the poor localization precision of Grid-Scan algorithm, an improved Grid-Scan localization algorithm based on virtual anchor nodes is proposed in Wireless Sensor Network （WSN）. Three related works of the improved algorithm are mentioned as follows：Firstly, setting the threshold of localizability for unknown node. The unknown node, the number of neighbor anchor node is greater than the threshold of localizability, is located by Grid-Scan, and the located unknown nodes are upgraded to virtual anchor nodes. Secondly, the number of neighbor anchor node which is greater than the threshold of localizability used the method of maximum likelihood to complete the localization, and the located unknown nodes are upgraded to virtual anchor nodes as well. Finally, anchor nodes and virtual anchor nodes participate in the localization of the remaining unknown nodes. Simulation results show that the improved algorithm, in difference of anchor node density, communication radius, grid size and irregular propagation models, has better localization precision.

Key words: Wireless Sensor Network（WSN）, Grid-Scan algorithm, localization precision, virtual anchor nodes, threshold of localizability, method of maximum likelihood