Improving APS with anchor selection in anisotropic sensor networks

Sensor networks are useful for environmental monitoring, military applications, disaster management, etc. In many applications, sensors are supposed to know their geographic locations. Some localization methods of sensor networks have been developed. In these methods, nodes equipped with special hardware to obtain precise location information, namely the anchor nodes, are employed to derive the locations of other nodes. Most of the existing work focus on increasing the accuracy in position estimation by using different heuristic-based or mathematical techniques. In this paper we show that selection of anchor nodes is a significant factor to the problem. We first demonstrate that using all anchor nodes does not give the most precise position. We then identify criteria of selecting "good" anchor nodes to achieve more accurate position estimation in anisotropic sensor networks. We develop a simple heuristic based algorithm to select "good" anchor nodes and evaluate its performance using simulations.