Research On Localization Algorithms Based On Mobile Anchors In Wireless Sensor Networks

The development and amalgamation of wireless communications, micro-electro-mechanical technology and digital electronics supply favorable conditions for the naissance and development of wireless sensor networks. Wireless sensor networks have been applied widely in many fields. In most of the applications, to obtain the position of nodes is an important precondition, therefore the localization technology of sensor nodes is one of pivotal technologies of wireless sensor networks. The positions of nodes are immobile in the existing algorithms, so the topology of network restricts the localization precision of the algorithm. The method that removing the immobile anchors by mobile ones not only can improves the topology and enhances the localization precision, but also decreases the amount of immobile anchors and reduce the cost. Thereby, the localization algorithms based on mobile anchors turn to be a hotspot.This paper focus on the localization algorithms based on mobile anchors, mainly includes the following two parts:Firstly, the LMAP algorithm must assume that transmission range of a sensor node is a perfect circle, but it does not come into existence in practice, which affects the localization performance. To solve this problem, an improved algorithm named ELMAP is proposed which utilizes RSS as the gists of beacon messages selection. The ELMAP algorithm shakes off the dependence on the assumption, achieves the purpose of making the algorithm applied in practice. The simulation resluts indicate that the ELMAP algorithm could felicitously accommodates the environment and locates nodes much accurately, and the localization performance could come to an optimization by proper filtration of beacon messages.Secondly, the SBL algorithm could mistakenly judges the localization regions of nodes, and localization precision is much large when the environment is complicated. To solve this problem, a new localization algorithm applied in emergency network named MSBL is proposed in this paper, which joins a parameter RSSP in SBL algorithm and replaces the immobile anchors by mobile anchors. This algorithm could precisely locates the region of a node and is affected by the environment much insusceptibly. The simulaiton resluts indicate the parameter RSSP could reduces the wrong judgement ratio of localization regions, improves localization precision and enhances the environment adaptability.