Research On The System Of Positioning Based On Wireless Sensor Networks

As the development of the technology such as wireless communications,embedded computing,sensors and micro-electromechanical systems(MEMS),wireless sensor networks (W- SN)consisted of micro-sensors with sensing, computing and wireless network communication capabilities has aroused of great concern. As a new information acquisition and processing techniques,wireless sensor networks can achieve complex large-scale monitoring and tracking tasks within a wide range of application areas .Node localization is one of the key technologies of wireless sensor networks. The accuracy of position estimation directly impact on subsequent transmission and monitoring of WSN network .This paper mainly studied the positioning of wireless sensor network node, introduced the concepts and principles of wireless sensor network node localization,explained the self-position systems, the index of algorithms performance and the calculating process of node position,discussed the existing classification of localization algorithm,focused on the principles and characteristics of the representative algorithm in the field in recent years, and briefly described the existing problem of the node positioning algorithm,the improving direction and the latest development.Through analysis, the accuracy of positioning is the primary evaluation index of the positioning technology,directly impact on the efficiency of the network and accuracy of the information transmission.There are mainly two reasons can affect the positioning accuracy:First, ranging error;Second,the calculation error.An effective way to improve localization accuracy is improving the ranging accuracy, but the difficulty lies in that the realization of ranging was limited by the energy of the node and the complexity and the volume of the hardware,such conditions.And in practical applications, ranging accuracy can not be infinitely improved, so we needed to further improve the accuracy of localization in algorithms. In connection with the specific application-scenarios,BP localization algorithm applied to fixed-node sensor network and Localization Algorithm for Mobile Nodes in Wireless Sensor Networks Based on Signal Strength and Motion Vector called SSMV for short, were designed in this paper.Through generalization and summarization,BP algorithm is proposed based on the analysis and comparison of the existing location algorithms of wireless sensor networks in-depth.BP algorithm optimize the positioning using the method of BP neural network.Through experiments and comparation with the least-squares algorithm,the advantages of the measure in improving positioning accuracy was furtherly proved. SSMV algorithm which is a new location algorithm without ranging based on the mobile beacon node,is proposed through studying the issue of mobile beacon node applied to WSN node localization.Through simulation experiments and analyzing the performance of the algorithm,we know that the algorithm has higher positioning accuracy,requires fewer anchor nodes,and reduces costs and communication overhead.SSMV algorithm is superior than the Convex- Programming algorithm in the same environment.