| Node localization technology is one main technology of wireless sensor network. The correct localization of node itself is a basic premise which guarantees the validity of monitoring information provided by node. The monitoring information which doesn't combine with the node position is meaningless. Node localization problem is a problem that according to a few known position nodes with certain positioning mechanism to seek unknown nodes. Wireless sensor network (WSN) is composed by a wireless sensor network structure. Limited to wireless sensor itself of structure and working principle, its signal propagation distance is limited, only in effective communication radius sensor communication can proceed. Generally,a node in the network only can connect a small amount of nodes. In range-based location algorithm,it locates unknown nodes depending on the distance information of multiple hops ranging nodes and known node location information,using some geometric method like trilateration and triangulation.In the process of the localization, certainty is very important question. It does not guarantee the determined position of the node with knowing the multiple hops ranging distance between nodes. There may be many different network topology with different node positions can meet the requirements of the ranging information. Now appears uncertain. As previously mentioned, the emergence of uncertainty will lead to inaccuracy localization of nodes, thus affecting the accuracy of the node gathering information. Therefore,how to guarantee the certainty is the key to the localization problem.Moreover,the researchers work on the main ideas of how to improve the node localization accuracy and put forward a lot of localization algorithm,focused mostly on two-dimensional space,but often ignoring the 3D and 2D space differences. One core problem of localization is ranging the distances between multiple hops nodes. With the distance between the nodes,we can use trilateration method to locate the nodes. In three-dimensional space compared with two-dimensional space, its calculation case more diverse, more complicated. How to conduct multiple hops involves multiple calculation result of the calculation of the state of a detailed analysis of the situation. Therefore,it is necessary to combine the multiple hops ranging of three dimensional space as a research to make a smooth transition into the three-dimensional space from two-dimensional space and to improve localization algorithm versatile.This paper mainly made two parts work. The first part proposed a localization algorithm which uses communication radius as a limitation in three-dimensional space. The second part is the development of 3D topology software tools.This paper proposed a localization method which uses communication radius as a limitation in three-dimensional space between nodes to limit the network shape so as to solve certainty and complete network node localization problem. And provided a iterative determination method to determine whether the network topology meets the conditions of the algorithm of this paper. The topology which meets the determination method can use the calculation model proposed after to calculate. Then puts forward to key mathematical model,focusing on how to solve the model and how to use it to calculate all unknown nodes to complete localization problem.In order to simulate the three-dimensional space node distribution situation, this part of work produced an three-dimensional node topology simulation generation software. The software is divided into two views, one is 2D view,the other is 3D view corresponding to 2D view which adopts bevel 2 measure projection. It can set section communication radius length,can add,delete,move,edit and display nodes. And it can export simulated node location information to file. Then combine with Matlab for research and analysis. |
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