Distributed Range Difference Based Target Localization in Sensor Network

Target localization is a key application in the sensor network context. Of the various conventional methods can be applied, and have been proposed, the range difference (RD) based method is attractive due to improved accuracy and ease of implementation it affords. While the basic concepts of the RD based method can be adapted to the case of sensor networks, the data acquisition and aggregation procedures need to be formulated and characterized subject to the energy constraint. The challenge is to design an efficient algorithm that is economical and still accurate. In this paper, based on range difference localization method, we propose a distributed algorithm which allows the time delay estimation to be carried out at each participating sensor. The acquired data is fused using a sequential least squares scheme which enables the appropriate sensor selection based on the current estimate. The results distributed localization produces smaller error and consumes less energy than the centralized method. The advantage of distributed localization in terms of the accuracy becomes more conspicuous when the number of participating sensors is small while the energy saving increases when the number of participating sensors to decreasing target signal energy and the instantaneous error from the sequence of estimates can be approximated and used to reconcile the cost and the system performance