The Research On Localization Algorithm Of Wireless Sensor Networks

The based on the range-free positioning algorithm is one of the research focuses in the node localization algorithm of the wireless sensor network. There mainly have two problems in the theory and practical research of the range-free DV-Hop algorithm at present. Many scholars at home and abroad have been proposed some related improved algorithms, but from the whole consideration those algorithms are not very satisfactory. The improvements of the DV-Hop algorithms are in two-dimensional space basically, but the real applications are concentrated in three-dimensional space. So in order to make the applications of the DV-Hop algorithm and its improvement algorithms is more extensive, not only improve these algorithms performance constantly, but also need extend these two-dimensional algorithms to three-dimensional space, and then apply it to real life.On the basis of reading a lot of reference, this paper using a variety of positioning optimization methods and the judgmental methods of the beacon nodes'validity, focus on how to improve the positioning accuracy and coverage of the node localization algorithm, the main studies of this paper are as follows.Firstly, start from the positioning technology of the wireless sensor network, analyzing the advantages, disadvantages and adaptation of the technology for the distance between nodes and the position calculation methods, and summed up the performance evaluation criteria of the node positioning algorithm, made a preparation in the positioning algorithm's accuracy improving and performance evaluating.Secondly, studying the positioning process, the network survival, the positioning accuracy of the DV-Hop algorithm, and the performance indicators in the anisotropic sparse network, analyzing the degree of the DV-Hop improved algorithms' pros and cons in theoretical, introducing the limited number of the hops, collinearity judgments, normalized weighting, total least squares and other methods to improving and optimizing the various stages of positioning, proposed an improving DV-Hop algorithm in two-dimensional, and through the simulation experiments to verify the correctness and efficiency of this algorithm.Lastly,extending the DV-Hop algorithm to three-dimensional space, proposed a new three-dimensional DV-Hop algorithm based mobile beacon. In order to reduce the network traffic, introducing the mobile agent technology to calculate the minimum hops of the beacon node. Using the translation coordinate method, draw circle method, and total least squares to locate the unknown nodes' coordinates according to the number of the beacon nodes, to improve the coverage. And verified the effectiveness and practicality of this algorithm by the simulation experiments.