Research Of Wireless Sensor Networks Unknown Nodes Localization Algorithm

Wireless Sensor Networks(WSN) are built up by the nodes decorated artificially or mechanically in the Specific areas and the nodes form a network by self-organization. The purpose is to acquire information and sent to observers through the coordination of the nodes to perception, acquisition and processing. WSN has a prosperous future in military defense, environmental monitoring, remote control in hazardous areas, etc. As a key technology for WSN, localization technology determines the quality of WSN. Localization technology is also the main direction in the study of WSN.In the actual application process, the node of WSN should be placed in three-dimensional environment. Based on traditional DV-Hop algorithm and DV-Distance algorithm, this paper improved these two algorithms and applied in three-dimensional space. Main work includes:(1) For DV-hop algorithm, it is more reasonable for the average distance of each hop selected by calculating the average distance of each hop of the 8 anchor nodes distributed in the border of the network area instead the traditional method. After the initial position of the unknown nodes is determined, the correction method of position is applied to reduce the position error of unknown node in order to reduce the node location error.(2) For the problem of fold line distance instead line distance causes the distance estimation error is too large in DV-Distance algorithm, we selects 8 anchor nodes distributed in the border of the network and uses the ratio between actual distance and estimated distance of the selected nodes as the correction weight. The correction weight is used to correct the efficient distance between nodes. After the initial position of the unknown nodes determined the correction method of position is applied to reduce the positioning error of unknown node in order to reduce the node location error.Matlab software is used to simulate the improved algorithm. Compared with the traditional algorithms, the simulation results shows that improved algorithms have advantages in reducing the positioning errors. Some nodes energy can be saved since the internal anchor nodes not participate in the process of the average distance of each hop selection in DV-hop and the correction weight selection in DV-Distance.