The Research On 3-D Localization In Wireless Sensor Networks

The position of sensor node is very important to practical application in wireless sensor network, we should know the position of event when it happens in wireless sensor network, then we should know the position of every sensor node. Otherwise the application has no practical significance. So the localization technology of sensor node is a fundamental function in wireless sensor network and it is a supporting technology of practical applications in wireless sensor network.Current localization schemes can be divided into range-based localization schemes and range-free localization schemes according to whether measuring the distance between two sensor nodes or not. The distance or angle information between sensor nodes to be localized and anchor nodes will be measured in range-based localization schemes, and then use trilateration and other methods to calculate location, range-free localization schemes only calculate location based on connectivity of wireless sensor network while distance and angle information are not needed. There are some range-based localization schemes as follows: TOA, TDOA, AOA and RSSI. There are some range-free localization schemes as follows: DV-HOP, APIT and CENTROID.Some researches on three-dimensional localization technology in wireless sensor network are carried out in this thesis, and main contributions can be concluded as follows:(1)Introduce mid vertical plane into three-dimensional localization, two anchor nodes within the communication range of sensor node to be localized can determine a mid vertical plane, the distance between node to be localized and anchor nodes can be inferred based on signal strength received and then judge which side of the mid vertical plane it's at. Secondary segmentation to region is carried out and localization accuracy is improved.(2)Introduce bounding-box into three-dimensional localization to determine the region of node to be localized firstly, and then treat other sensor nodes to be localized within communication range as reference nodes; we propose a new localization scheme to reduce the region of node and localization accuracy is increased significantly. This scheme has low operation cost and can prolong lifetime of wireless sensor network.