Study On Location Method Of Wireless Sensor Networks

Wireless Sensor Network(WSN)is widely used in many fields such as national defense,military and environmental monitoring,but the data collected from its monitoring can only be meaningful when combined with the location information of Sensor nodes.Therefore,node positioning with high accuracy is the basis and premise of WSN application.At present,most of WSN's node location algorithms are only applicable to some application environments and cannot solve all localization problems faced by sensor networks.Node location algorithms are still hot topics full of challenges.The background and significance of WSN node location and the domestic and international status of WSN is discussed in detail.At the end of first chapter concludes with the main research contents of the dissertation.The second chapter describes the architecture of WSN,the structure of sensor nodes and the characteristics and key technologies of WSN.The basic principle of node location and the calculation method of node position are expounded.The localization principle,advantages and disadvantages of several classical localization algorithms are analyzed.Finally,the performance evaluation index of the localization algorithm is described.The third chapter introduces the indoor secondary positioning method based on received signal strength and an improved weighted centroid localization algorithm.The indoor secondary positioning method based on received signal strength optimizes the processing RSSI value and corrects the path loss index according to the application environment,which effectively improves the positioning accuracy of the algorithm.An improved weighted centroid localization algorithm is appropriately increased within the allowable range of node energy consumption.The complexity of the algorithm reduces the dependence of the centroid localization algorithm on the network connectivity and extends the application range of the algorithm.The fourth chapter studies an iterative estimation method for WSN three-dimensional positioning.The existing WSN three-dimensional positioning algorithm is mostly based on the principle of two-dimensional positioning algorithm which is relatively mature and has good algorithm performance,and is extended to three-dimensional space to realize node positioning.Therefore,based on the principle of WSN two-dimensional localization algorithm based on centroid iterative estimation,an iterative estimation method for WSN three-dimensional positioning is proposed.The algorithm first obtains the RSSI from each beacon node,and calculates the centroid coordinates of the three-dimensional space formed by the current communication target node.Then,the centroid is used to replace the beacon node furthest away from the unknown node,so as to reduce the three-dimensional space enclosed by the connected anchor nodes and improve the localization accuracy of the algorithm.The experimental results show that the algorithm has lower power consumption and larger application range.In the fifth chapter,based on radar localization,the WSN node localization algorithm based on signal phase search is studied.Firstly,the signal subspace and the noise subspace separated by the Projection Approximation Subspace Tracking(PAST)technology in order to ensure that the node receives the signal phase information.Based on the principle of cosine similarity algorithm,the construct of the objective function according to the node receives the signal phase information and calculates the phase information of the pixel unit,and the entanglement problem of the signal phase information is overcame,thus the node location problem is transformed into the optimal solution of the search objective function.Based on the principle of centroid localization algorithm,the initial search pixel unit position is determined according to the position information of the communication target node.Finally,the gradient descent method is used to quickly search for the optimal solution of the objective function,and the time taken to locate the unknown node is reduced.The simulation results show that the algorithm has lower power consumption and can accurately locate unknown nodes.Chapter six summarizes the main research work of the dissertation,and forecasts the research of WSN node location.