Locating Remote Nodes in Anchor-free Wireless Sensor Network

In wireless sensor network, it is always important to obtain accurate relative positions of each sensor node, especially when there is no anchor node in the network to provide an absolute coordinate system. In this paper, this problem was first addressed by building a local coordinate system to express relative locations. Then the Cramer-Rao lower bound (CRLB) in an anchor-free network is analyzed, and used to find the optimal path for locating a remote node through vector addition. Some geometric problems in the path setup process are also addressed. Through simulation, the authors showed that the proposed method could give better accuracy than previous similar approach, and even in certain case could outperform some other approach which has higher computational cost.