Collaborative localization algorithm for wireless sensor networks using mobile anchors

Wireless sensor networks (WSNs) are a large ad hoc networks of distributed sensors that are equipped with low power supply modules. Location information is a basic requirement for many WSNs applications. Because localization accuracy is sufficient for many sensor network applications, range free localization schemes based on RSSI technique are being pursed as a cost effective and convenient alternative. In this paper, based on RSSI technique, we present a novel collaborative localization algorithm for wireless sensor networks using a group of mobile anchor nodes (GMAN). A sensor node estimates its location by receiving beacon messages from a GMAN. A GMAN is usually composed of three identical anchor nodes and their relative locations remain constant. The GMAN is equipped with a GPS and moves around in the sensor area and periodically broadcasts beacon messages. Sensor nodes take selected positions on the trajectory of the GMAN as beacon points. Simulation results show that our proposed localization scheme outperforms the other mobile-anchor-node based schemes in accuracy when irregular radio pattern and random node placement are considered.