Research On Distributed Cooperative Localization Algorithms For Wireless Sensor Networks

In recent years,wireless sensor networks have been widely used in various fields,and have made great contributions to human production and life.Among related technologies,the localization of sensor nodes plays an essential role in the effective application of wireless sensor networks,and it is also a research focus in wireless sensor networks.As a newly arisen positioning method,cooperative localization has drawn extensive attention from scholars in related fields due to its obvious advantages.This paper studies the distributed cooperative location problem of wireless sensor networks.The main work of this paper is listed as follows:The first chapter introduces the research background and significance of the cooperative location of wireless sensor networks,and analyzes the current research status in the field at home and abroad.Then,the motivation and derivation of main work is presented.The second chapter investigates the localization problem based on hybrid measurements in two-dimensional space.Suppose that there are three types of nodes distributed on the plane and each type of node can obtain only one type of information,namely distance,bearing or relative position.Besides,each node has its own local coordinate system without common orientation.Then,according to the different combinations of measurement types between nodes,schemes for calculating the barycentric coordinates are given.Next,based on the obtained barycentric matrix,a distributed cooperative location algorithm is designed not only for the exact measurement but also for the noisy measurement,which enables unknown nodes achieve distributed localization cooperatively only use the information from neighbors.Furthermore,some necessary and sufficient conditions are given for the global convergence of the algorithm.Finally,the effectiveness of the algorithm is verified by numerical simulation examples.The third chapter studies the localization problem based on mixed measurements in three-dimensional space.Compared with the localization in the two-dimensional plane,the localization in three-dimensional space is more suitable for some complex spatial application scenarios.Therefore,this chapter considers wireless sensor networks in three-dimensional space.It is assumed that the sensor nodes distribute in three-dimensional space,and each node is capable of measuring only one type of information to near-by nodes,such as distance,bearing or relative position.Additionally,the local coordinate system of each node is aligned to the global coordinate system.Then,the measurement type combinations that can obtain the barycentric coordinates of nodes are analyzed in detail.Next,a distributed cooperative location algorithm is proposed using the Laplacian matrix.Furthermore,some sufficient and necessary conditions are given for the convergence of the algorithm with not only exact hybrid measurements but also noisy hybrid measurements,it is proved that the convergence of the algorithm does not rely on the selection of the initial positions.Finally,simulations are provided to illustrate the performance and effectiveness of the proposed distributed cooperative localization scheme.The fourth chapter summarizes the main results of this thesis and forecasts the research direc-tions in the future.