Research On Localization Algorithm Based On Mobile Anchor Nodes In Wireless Sensor Networks

With advent of the era of networking,wireless sensor network technology has attracted more and more attention in intelligent medical,emergency rescue,intelligent transportation,military applications and other areas.Therefore,wireless sensor network localization technology is one of the key technologies to support the service system of wireless sensor networks.The existing localization algorithms for wireless sensor networks are mostly based on static anchor nodes.However,there are some problems in the localization algorithm with static anchor nodes,such as the positioning accuracy is heavily dependent on anchor node allocation density.Therefore,the cost will be significant and it is difficult to deploy on a large scale.Thus,mobile anchor nodes are used to replace the static anchor node during the moving process.The algorithm can not only reduce the cost of localization,but also improve the topology of the whole wireless sensor network.Therefore,research on WSN localization algorithm for mobile anchor node have gradually become a hot topic in the field of location aware.This thesis focuses on the mobile anchor node-based localization algorithm:(1)This thesis briefly introduces the key technologies,characteristics and application of Wireless Sensor Networks.Then,in the aspect of node localization technology,this thesis introduces some typical WSN positioning algorithms,compares and analyzes the typical range-based and range-free algorithms.This thesis focuses on the typical node localization algorithm based on mobile anchor node and the corresponding path planning method.(2)Facing to range-based algorithms,in order to solve the problem that the traditional location method is invalid due to the large error of GPS position information in the high speed moving of the anchor node.This thesis presents an algorithm based on the moving path of diameter-varying spiral line.In this algorithm,the high precision measurement method of time parameter is used to replace the GPS position information,and the inherent error of the device is solved.At the same time,the anchor node is equipped with directional antenna,which can effectively improve the coverage and practical value of localization.Simulation results show that the algorithm has good performance and high positioning accuracy.(3)As for range-free algorithms,this thesis proposes an improved DV-Hop localization algorithm for mobile anchor node based on range correction.The mobile anchor node moves within the location area according to the Scan moving path,and uses the virtual anchor node instead of the static anchor node.Meanwhile,RSSI is used to improve the selection of nearest neighbor anchor nodes and the calculation method of average hop distance.Finally,the algorithm need to establish the distance equations and calculate the coordinates of the nodes by using the least square method.The simulation results show that the improved algorithm is more stable than the original algorithm,and the positioning error is smaller.