FlagLoc: Localization Using a Flag for Mobile Wireless Sensor Networks with Measurement Errors

Indoor, underground, or underwater threedimensional (3D) localization provides fundamental support to the applications of mobile wireless sensor networks (WSNs). In these applications, a single robot cannot work, as there are no GPS signals and few references for the robot to loalizae itself in the large in-door spaces. Existing in-door localization approaches usually rely on the projection of the 3D topology graph onto a horizontal plane. Such projection is infeasible in a narrow vertical space, either, since it requires three location-known nodes, called anchors, as reference nodes on a large horizontal plane. In this paper, we propose a new distributed 3D localization protocol, FlagLoc, for the mobile WSNs. FlagLoc uses a flag that is composed of three anchor nodes on a plane of any angle to start the localization and to lead the network motion of a mobile WSN. Furthermore, FlagLoc compensates for distance and motion measurement errors. The evaluation shows that FlagLoc significantly outperforms the existing state-of-the-art schemes in terms of accuracy.