Adaptive localization algorithm in distributed asynchronous wireless sensor network

This paper presents a target tracking algorithm based on the synthesized information of signal's time-of-arrival (TOA) in an asynchronous distributed wireless sensor network (WSN). The proposed algorithm combines displacement estimate (DE) and position-displacement estimate (PDE) together, and the case of target's very slow motion is mainly focused on. Taking advantage of DE's efficiency and PDE's ability of eliminating accumulated error, the effect of tracking is fairly good and the validity of the algorithm is guaranteed as well. An adaptive threshold is introduced to switch from DE to PDE so as to eliminating the error accumulated in a series of consecutive DE estimates. And the error of estimating current target's position between these two methods is used to adjust threshold for activating the next switch. Simulations show the proposed method has quite good accuracy and availability in aimed cases as well as other situations.