Wireless Sensor Network Positioning Technology Research

Advances in micro-electro-mechanical system technology, wireless communications technology and computer technology have enabled the development of low-power, low-cost, multifunctional micro-sensor nodes, and then promoting wireless sensor networks for rapid development. The basic task of wireless sensor networks is to obtain valuable information of the physical world accurately. However, there are many restrictions such as calculation, storage, reliability of wireless communications and network bandwidth in wireless sensor networks. It is very import to investigate the high efficiency of sensor nodes, locatiozation of low energy consumers of wireless sensor networks.The key technologies in wireless sensor networks include network communication protocol, core supporting technology, self-organization and management and application technology. Node localization is one of key technologies to support wireless sensor networks. The precise node location is the premise that not only determines the position of some events and targets in the net, but also deals with target recognition, monitoring, navigation, and so on in many applications. Moreover, it is the basis of numerous links such as node cover, routing protocols, network topology control. It is the prerequisites to wireless sensor networks working highly quality. The network seamless coordination and interaction with the physical world are realized by localization technology. Without it, everything else is pointless.In this paper, according to wireless sensor networks, there are many challenges of designing a feasible node localization scheme, such as complicated physical environment, the limited network resources and so on. In order to discuss the distributed localization scheme suitable to wireless sensor networks, the fundamental of the basic principle of localization algorithms for wireless sensor networks is expounded and typical localization algorithms are analyzed and compared. The characteristic of DV-Hop algorithm is dissected, a novel algorithm limited weighted DV-Hop is proposed in this thesis. The improved algorithm, which is based exclusively on connectivity, will gain higher localization precision and less energy resource without extra hardware, decrease cumulative errors and communications traffic resulted form DV-Hop algorithms.Simulation is one of the important means in the research and development in wireless sensor networks. The improved DV-Hop algorithm and DV-Hop with the proposed propagation methods is simulated in MATLAB. The simulation shows that our algorithm is less influenced by circumstances and 8% better in isotropic topology and 50% better in the "C" shape network than DV-Hop algorithm. The improved algorithm promises better position estimation.Based on the algorithm above, an approach is briefly introduced to deal with the rest nodes. It prolongs the life of nodes meanwhile ensuring more efficiency of network coverage. Therefore the improved algorithm will meet all kinds of localization needs in different circumstances and keep the required localization accuracy. In addition, ZigBee is a novel short distance, low power and high-redundant wireless communication technology, which meets the need of application in wireless sensor networks. Dangerous goods monitoring system design is proposed based on ZigBee agreement for adapting the practical application such as distant measuring and controlling, precautionary emergency, speed succor etc. The issue of dangerous goods monitoring in practical application is figured out successfully.