GPS-free and Anchor-free Indoor Localization for Wireless Sensor Networks

In wireless sensor networks (WSNs), many applications require location awareness. GPS is generally not suitable to establish indoor locations. In this paper, we propose a GPS-free and Anchor-free (GFAF) indoor localization algorithm. GFAF algorithm uses a mobile node to move according to a special trajectory in deployment area and the mobile node calculates its real-time coordinate according to the start coordinate and move information, and then the mobile node broadcasts its current coordinate to unknown nodes within its transmission radius, and finally the unknown nodes can use these broadcasted coordinates and the observations between unknown nodes and mobile node to calculate their locations based on a posterior probability formula. In contrast to current up-to-date anchor-based localization methods, the proposed algorithm is fully distributed, where each unknown node only needs the information of real-time observation and mobile node coordinate, without cumbersome partitioning and merging process. The algorithm is highly scalable, with limited error propagation and linear computation and communication cost with respect to the size of the network. Extensive simulations and comparison with other methods under various representative network settings are carried out, showing superior performance of the proposed algorithm.