Study On Node Location In Complicated Three Dimensional Environment

As a new generation of intelligent networks, WSN is characterized with wide coverage, strong self-adaptability, self-organization and self-healing, extensively used in the field of health care, the environment, military, etc. Location technology is one of the key technologies in WSN.The paper describes the key technologies and features of WSN, the research status of node location, and analyzes the location algorithms of WSN and the performance indicators systematically, and also studys the three-dimensional node location algorithms in depth.The existing three-dimensional location algorithms utilize static beacon nodes to achieve three-dimensional location of nodes, positioning accuracy depends highly on the number of the beacon nodes, while increasing the number of beacon nodes, the cost and the energy consumption of the network will increase.To solve these problems, we introduce an assistant equipment in the paper, advertising mobile beacon message to achieve three-dimensional location of the nodes, and we deduce the fundamental theory of three-dimensional node location, as well as plan the trajectory of assistan equipment. In the first stage of the prorposed algorithm the ordinary nodes passively receive beacon message, obtaining the distance to the beacon message by RSSI ranging, calculating their position by three-dimensional multilateration method. Considering that in the practical environment some of the ordinary nodes can not receive the beacon message satisfied with the conditions, thus on the basis of passive location of the first stage, we propose the second stage of active positioning process, improving the location rate of the ordinary nodes greatly.In addition, we also design the location process of the nodes and the format of the data packet involved in the node location process, and we also analyze the factors affecting the node location error and how the factors influence the location estimation of unknown nodes,and we also analyze the energy consupmtion of ordinary nodes invlolved in various stages.Finally, we simulate the algorithm and compare with three-dimensional DV-Hop algorithm.The simulation results show that the proposed algorithm has high location rate and the nodes have small energy consumption, the algorithm has stable performance and the algorithm performs better than DV-Hop algorithm in average location error, location rate, and average energy consumption.