An Accurate GPS-Based Localization in Wireless Sensor Networks: A GM-WLS Method

For wireless sensor networks, localization is crucial due to the dynamic nature of deployment. In absolute localization, a few nodes (called beacon nodes or anchors) need to know their absolute positions, and all the other nodes are absolutely localized in the coordinate system of the beacon nodes. Most of GPS-based localizations belong to absolute localization, and localization systems enable nodes to fix their positions in a global coordinate system using a relatively small number of beacon nodes that know their position through external measurement (e.g., GPS). Considering inevitable errors from unreliable GPS observations, the localization result will not be accurate. In this paper, we propose a Weighted Least Square (WLS) method for GPS-based localization to get more accurate position of sensor nodes that are not equipped with GPSreceivers. Following the description of the WLS algorithm as well as the localization system based on it, simulation analysis and real world experiments demonstrate the effectiveness of the proposed approach.