Research On Localization Of Center-free Dynamic Cluster Network Nodes

With the rapid development of wireless communication technology and electronic components,integrated chips gradually present the characteristics of miniaturization and micromation,and the dynamic cluster network developed with it has gradually attracted widespread attention from scholars and application markets.Dynamic cluster network can achieve better performance than single network node through multiple nodes cooperation,it has many advantages,such as large coverage area,high reliability,strong anti-interference ability,multi-target monitoring and information collection at the same time,and can execute multi-task simultaneous.Dynamic cluster network has been applied in regional target monitoring,information collection,target search and tracking,military operations,intelligent management and other fields,so the research on the positioning of dynamic cluster network nodes has important scientific research and commercial market value.Compared with the static network scenario,the positioning of dynamic cluster network nodes needs to consider more problems,mainly including: 1)Dynamic positioning algorithm needs to obtain the position information of the mobile node continuously changing.2)Compared with the static node,the constraint of energy,communication and other resources of the mobile node is more strict,so the positioning algorithm must consider the positioning cost while focusing on the positioning accuracy.3)The dynamic network environment is complex,and the positioning algorithm needs to have certain exception handling capability.In view of these problems,in absence of external auxiliary positioning equipment such as satellite navigation and inertial navigation,this thesis proposes two dynamic cluster network positioning schemes:The first one is an improved combined trilateral positioning algorithm based on the simple and efficient triangulation algorithm,The strategy of combining the neighbor anchor nodes multiple positioning to obtain candidate points set is adopted to control the positioning error of each round at a low level,which alleviates the error propagation and accumulation problem of trilateration localization in multi-hop network.Furthermore,the selection of the anchor nodes and the filtering operation of the candidate points set improve the positioning accuracy,and meanwhile ensure the algorithm can deal with some abnormal distance measurement data existing in the localization process.Finally,simulation experiments show that the combined trilateral positioning algorithm improves the positioning accuracy by 50.44%,19.85% and 68.66% respectively,compared with the minimum condition number trilateral localization algorithm,multilateral localization algorithm and classical MDS algorithm.And compared with some other algorithms based on triangulation with fault-tolerant processing ability,the algorithm in this thesis also shows better fault-tolerant performance.The other one is a node energy constraint clustering-based MDS localization algorithm,which is proposed because of the classical MDS algorithm with high complexity and the large error of the shortest path distance replacing the actual distance between nodes.The cluster-based MDS first divides the overall network into smaller local sub-networks,by clustering,the time complexity of the algorithm and the overall communication cost of the network can be greatly reduced,At the same time,it can better deal with the topological variability caused by the movement of dynamic network nodes,and it does not need to construct the global network distance matrix,energy constraint clustering also ensure network load balance.Then use the SMACOF iterative refinement algorithm in each cluster for relative positioning.Finally,the coordinate representation based on homogeneous coordinates is used to fuse each cluster,thus get the global network composition.Simulation experiments show that the MDS algorithm based on energy constraint clustering has better performance in terms of computational complexity and communication cost,and compared with the other three cluster-based MDS algorithm,CMDS,MDS-MAP(D)and MDS-MAP(P),the positioning accuracy can be improved by more than 50%.