Abstract:

Rangebased localization schemes are sometimes not feasible due to hardware cost and resource restriction of sensor nodes. The geometric relationships and communication constraints among unknown node and anchor nodes are studied. A weighted centroid localization algorithm based on intersection of anchor circle is proposed. If there are anchor nodes within the communication range of an unknown node, the unknown node must be inside the triangle constituted by the intersection of the anchor circles. It is assumed that the location estimation of the unknown node is the triangle centroid. To increase the positioning accuracy an improved scheme is proposed. It uses RSSI as weight function and takes the weighted centroid of the triangle as the location estimation of the unknown node. This rangefree algorithm is based exclusively on connectivity of sensor networks. The communication and computational loads are small. Simulation results show that the relative localization error is 22.7% when 100 sensor nodes are randomly deployed in 100 m×100 m scenario with 30 m communication range, and the anchor density is 16%.

Key words: communication technology, wireless sensor networks, node location, centroid scheme, weighted, intersection of anchor circle