关键词: 无线传感器网络, 节点自定位, 周期定位机制, 最小二乘估计

Abstract: Nodes self-localization algorithm is an important part of a wireless sensor network system.It is also the basis on which all the applications of such a system can be implemented.A self-adaptive periodic localization algorithm based on least square estimation uses a periodic localization mechanism to control node locations in a network.Range acquisition technique based on the strength of received signals is used to acquire the distance between nodes.Localization period is activated till localization is finished.For unknown nodes，the primitive location is acquired through the maximum likelihood estimation，while the final location is determined by least square estimation.Emulational tests show that such an algorithm can significantly improve the localization rates of unknown nodes in a network，thus effectively inhibiting the spread of range acquisition errors.Accuracy of nodes localization also increases in the process.

Key words: wireless sensor networks, nodes self-localization, periodic localization mechanism, least square estimation