Research And Simulation Of The Self-Localization Algorithm In Wireless Sensor Networks

WSN(Wireless Sensor Network) refers to the self-organizing multi-hop networks, in which the monitoring area is composed of many micro-sensor nodes and are formed by wireless communication, aiming to collaboratively perceive, collect and dispose the information from the perceived objects in the network overlay area, and then send to the observer. This network has the advantages of remote monitoring and real-time monitoring, and it can work in bad and special conditions and so on, so WSN can be widely applied to manufacturing, traffic management, environment monitoring, medicine and health, national defense military, anti-terrorist anti-disaster fields.So recently, WSN is a entirely new technology, many key technology need to be researched. Location is one of the key technology. The location technology is the basement of the most application, especially military application. The location scheme and algorithm of WSN is consisted of two part:Self-Location and External-Location. The former is the basement of latter. The research about Self-Location is the hot point.The node Self-Location algorithm in WSN is classified to two types:Location algorithm which need not to measure distance and is based on measuring distance. The location algorithm which needs not to measure distance was considered as an effective strategy. DV-Hop(Distance Vector-Hop) algorithm is easy realized node Self-Location algorithm. In this algorithm the node need not to measure distance, the requirement for anchor node ratio is fewer, and location accuracy is higher. So it has been a classic strategy.But there is many disadvantages in this algorithm, such as existing node which is unable to location, existing unavoidable error, receiving redundancy information for every anchor node.According to the disadvantage above, a modified algorithm is proposed in this thesis. In the modified algorithm, two schemes are introduced, the one is removing the node unable to locate and setting life period for transmit information, which reduce the communication between nodes and average location error. The other is change the nodes located to anchor nodes. Using the anchor nodes to locate iteratively, the range of nodes located extents to whole network. So coverage of nodes has been increased effectively. Based on algorithm proposed, the experiment platform on Matlab has been built, and many experiments have been processed. The experimental results indicate that the modified DV-Hop algorithm is higher than conditional DV-Hop algorithm at communication cost, average location error, and coverage of nodes located.