Range-free node localization for mobile wireless sensor networks

Device localization or positioning is a fundamental research issue in sensor networks community. A small number of anchors that know their locations are used for supporting node localization. However, most localization schemes aimed at static sensor networks and can not be forthrightly applied to mobile sensor networks. This paper proposes a distributed range-free localization scheme which is extended from the MAP scheme (K. F. Ssu et al., 2005) for mobile sensors. In this scheme, each anchor broadcasts its location information as it moves within the sensing field. Each sensor node then estimates its own location by applying basic geometry principles to the location information. The scheme removes the requirement for specific ranging hardware, avoids the need for any interaction between the individual sensor nodes, and is independent of network densities. The scheme has been evaluated based on the network simulator ns-2. The simulation results demonstrate that the localization scheme significantly improves the MAP scheme.