High accuracy localisation scheme based on time‐of‐flight (TOF) and directional antenna in wireless sensor networks

Abstract

Node localisation technology is one of the most challenging and important issues in wireless sensor networks. This study puts forward a novel and high accuracy estimation method by combining distance-measuring with angle-measuring. An anchor node equipped with a directional antenna periodically sends beacons containing its position and antenna orientation to unknown nodes. By observing the variation of received signal strength indication values of beacons and the time of flight values, an unknown node can estimate the distance and orientation relative to the beacon node simultaneously. This study proposed an online modelling method to calibrate the shift of the estimated distance. Meanwhile, an angle estimation method is presented to avoid an ambiguous result, which is a new weighted curve fitting method based on least square principle. The experimental results show that the proposed ranging and angle measurement reaches a better localisation accuracy compared with the original ranging and angle method.