Research On 3D Positioning Technology In Wireless Sensor Network

Wireless sensor network is a comprehensive network that spans multiple fields in the21 st century,supported by many technologies.The node positioning technology is the key technology that determines the reliable and effective information received by the user terminal,which directly affects the positioning accuracy of the network.At present,research on node localization algorithms in three-dimensional(3D)space has become a development trend.The improvement of the existing 3D space node localization algorithms can effectively reduce the node localization error and improve the node localization accuracy.In this thesis,the node localization algorithms in 3D space is studied to improve the localization error and coplanarity of anchor nodes in the current algorithms.The main research contents and work results of the thesis are as follows:1)By studying the 3D-DV-Hop(three-Dimensional Distance Vector-Hop)positioning algorithm and on the basis of the related improved positioning algorithms,Based on the shortcomings of existing algorithms,two improved positioning algorithms are proposed:one is an improved positioning algorithm for static anchor nodes;the other is an improved positioning algorithm for mobile anchor nodes.2)Aiming at the positioning error generated by the node positioning algorithms in 3D space,an positioning algorithm based on weighted and least square curve fitting in 3D space is proposed.The algorithm first performed error weighting on the positioning error generated after the initial nodes positioning,then the centroid weighting factor optimization is performed on the processed unknown nodes coordinates,and finally the least-squares curve fitting is used to further correct the coordinates of unknown nodes.The simulation results show that compared with the 3D-DV-Hop positioning algorithm and the improved positioning algorithms proposed by other scholars,the positioning error of the algorithm is relatively low.3)In order to further reduce the positioning error generated by the node positioning algorithms in 3D space,aiming at the coplanarity of anchor nodes in the node localization algorithms,this thesis proposes a 3D space positioning algorithm based on the anchor node group moving along a prescribed path.First,the 3D deployment area is subjected to dimensionality reduction processing,and a set of mobile anchor node groups are deployed on each layer of the two-dimensional(2D)plane and allowed to move according to a certain moving path.Second,the minimum solid angle method is used to measure the coplanarity value of all virtual anchor node groups,and a threshold is set to filter out the virtual anchor node groups with poor quality.Finally,the virtual anchor node groups is used instead of the moving anchor node groups to solve the average hop distance,and the coplanarity value weighted distance is used to relocate the unknown nodes.The simulation results show thatthe algorithm can effectively reduce the positioning error caused by the coplanarity phenomenon of anchor nodes,and further reduce the positioning error of the network.