EGL: Efficient Geometry-based Localization in Wireless Sensor Networks

Abstract

Localisation of sensor nodes deployed randomly is one of the most challenging issues in wireless sensor networks. Position information of nodes helps in effective coverage, routing, data collection, target tracking, and event detection. This paper describes a localisation scheme where an unmanned aerial vehicle (UAV) equipped with a global positioning system (GPS) unit scans the sensing field while periodically broadcasting its current position. The sensor nodes estimate three boundary points on its communication circle and then, using simple geometry rules, estimate their location. The scheme neither requires extra hardware nor any interaction for ordinary sensor nodes with their neighbours. Several enhancements, including detection and correction of boundary points errors, are explained. This scheme is accurate and efficient enough to tolerate obstacles in the sensing field. Simulation results show that localisation accuracy can be adjusted by properly selecting UAV speed and beacon interval along with the UAV scan pattern.