Sensor Network Localization Based On Special Anchor Nodes

Wireless sensor network(WSN)localization problem with given or measured data between enough neighboring pairs is to find precisely an assignment of coordinates to all sensor nodes.Position-awareness is a prerequisite for almost all tasks,and node position information can also support diverse WSN protocols and algorithms.So WSN localization has been one of the hottest topics in WSN research in recent years.Despite a large number of approaches are developed for localization,there are still many unsolved problems in the area.The challenges to be addressed are both in high complexity of localization algorithms and lack of effective localization algorithms about special anchor layout.Therefore,this dissertation draws on WSN unique localization problems about special anchor layout for low complexity and high precision.The major work and innovative achievements can be divided into the following:1.Research has been done on special anchor layout.According to different power,anchor node can be divided into the anchor node with infinite power,the ordinary anchor node and the limited power anchor node.According to different type,anchor node can be divided into the anchor node with omnidirectional antenna and directional antenna.The layout of anchors is cross in the circular sensing field.Then,the localization precision of sensor node is improved and the time complexity is decreased through reasonable anchor node layout.2.Given distance measured,the node's position is estimated through the inter-node distances.We put forward the cross distance algorithm to locate the node for the anchor node with infinite power and the time complexity is decreased.Through taylor series one iterative algorithm,the errors reach the CRB(Cramer-Rao Bound)lower bounds and location precision becomes high in result.For ordinary anchor node and limited power anchor node,the adapted DV-Distance algorithm is proposed for deceasing distance estimation's error between node and anchor node.The location precision becomes high in result.3.Without distance measured,the node's position is estimated through the inter-node distance differences or hops.We put forward the cross distance difference algorithm to locate the node for the anchor node with infinite power and the time complexity is decreased,the inter-node time synchronization is avoided.Through taylor series one iterative algorithm,the errors reach the CRB lower bounds and location precision becomes high in result.For ordinary anchor node and limited power anchor node,the adapted DV-HOP algorithm is proposed for deceasing distance estimation's error between node and anchor node.So the location precision becomes high.4.Considering anchor node with directional antenna,the node's position is estimated through the angle of arrival of anchor node.We put forward the cross angle of arrival algorithm to locate the node and the node's configuration complexity is decreased,both the inter-node time synchronization and inter-anchor node time synchronization are avoided,the time complexity is decreased in result.Through taylor series one iterative algorithm,the errors reach the CRB lower bounds.5.Maximum likelihood estimation linearize algorithm on cellular network is put forward for the big error of the least squares algorithm and the high time complexity of maximum likelihood estimation.it is found that the time complexity is low and the errors reach the CRB lower bounds.6.An improved localization algorithm based on the mobile anchor node is given.Improved localization algorithm's aim is to avoid antenna redundancy,long traversal path and big error.The localization algorithm on sound sensor is proposed for reducing multipath interference.It's adaptability to the environment is increased.