The Research Of Node Localization Algorithm In Wireless Sensor Networks

Wireless sensor networks(WSNs)have perception,collecting data and wireless communication ability.And have great application value in military,industrial control,civil forest fires,urban traffic and so on.In WSNs,the location of nodes is important both in network operations and in most application layer tasks.Sensory data without spatial and temporal coordination is of very limited use.The process of determining the position of the sensor node deployed is called location.Location known sensor nodes are helpful to enhance the performance of routing protocols,target tracking techniques,and disaster response systems.Node location problem has received great attention,and for the correct system operation,improving the node positioning accuracy is very necessary.This paper firstly introduces the definition and characteristics of WSNs,and describes the concept of node location.Secondly,mobile anchor assisted localization research is summarized,where mobile assisted node positioning scheme and trajectory planning is introduced respectively.For the wireless sensor network positioning problem,we made the following two parts of the specific implementation:1)Three typical algorithms(Centroid algorithm,Bounding_Box algorithm and RSSI algorithm)are simulated in the following two circumstances: In the first case,once the blind node knows its own position,will own as an anchor node,and then locate the remaining blind nodes together with other anchor nodes;The second case,we use anchor nodes to locate the blind nodes,and if there are still blind nodes which cannot be located,we use anchor nodes and the nodes which have been located together to locate them.The experimental results show that the second case is better than the first case,and with the increase of the proportion of the anchor nodes,the positioning error is obviously decreased,and the number of un-located nodes is also decreased.The experiment provides the optimal solution about proportion of anchor nodes,and provides reliable basis for engineering practice.2)Propose two mobile anchor node location algorithm(RSSTB algorithm,DAB algorithm).WSNs initially contains a location-aware mobile anchor node and some static nodes which do not have location information.The position estimation of the unknown node can be obtained by the location information of the mobile anchor node,and can be positioned even in the presence of obstacles.Both algorithms use the received signal strength.The first algorithm controls the trajectory of the mobile anchor node and uses geometric properties to simplify the position estimation of the unknown node;and the second algorithm utilizes the direction information.The simulation results show that the two algorithms proposed in the paper are better in positioning accuracy than other RSS-based algorithms.Finally,the research contents is summarized.And we put forward the problems that can be explored in the future for the node location problem in WSNs.