The problem of target localization in WSN (wireless sensor network) has received much\nattention in recent years. However, the performance of traditional localization algorithms will\ndrastically degrade in the non-line of sight (NLOS) environment. Moreover, variable methods have\nbeen presented to address this issue, such as the optimization-based method and the NLOS modeling\nmethod. The former produces a higher complexity and the latter is sensitive to the propagating\nenvironment. Therefore, this paper puts forward a simple NLOS identification and localization\nalgorithm based on the residual analysis, where at least two line-of-sight (LOS) propagating anchor\nnodes (AN) are required. First, all ANs are grouped into several subgroups, and each subgroup can\nget intermediate position estimates of target node through traditional localization algorithms. Then,\nthe AN with an NLOS propagation, namely NLOS-AN, can be identified by the threshold based\nhypothesis test, where the test variable, i.e., the localization residual, is computed according to the\nintermediate position estimations. Finally, the position of target node can be estimated by only using\nANs under line of sight (LOS) propagations. Simulation results show that the proposed algorithm\ncan successfully identify the NLOS-AN, by which the following localization produces high accuracy\nso long as there are no less than two LOS-ANs.
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