A Robust Node Localization Method to Address Flip Ambiguity in Wireless Networks

Node flip ambiguity is a key problem that needs to be addressed for the range-based node localization in wireless sensor networks. A Robust Node Localization Method (RNLM) is proposed in this paper. It is a two phase methods. In the first phase, the orthogonal projection detection method is adopted to detect the unknown nodes needed to be positioned. For the unknown nodes that will not occur flip ambiguity, the least squares method is adopted to locate them. In the second phase, for the unknown nodes that may occur flip ambiguity, based on the topological constraints of the networks, an objective function is generated and Particle Swarm Optimization is adopted to find the minimum value of the objective function. In this way, the estimated locations of those nodes are obtained. The simulation results demonstrate that RNLM can effectively deal with the problem of node flip ambiguity.