Research On 3D Localization Algorithm Of Wireless Sensor Network Based On Unmanned Aerial Vehicle

Wireless Sensor Networks(WSNs)has been widely applied in various fields such as military,medical treatment,industrial production and our daily lives.For example,when it is deployed in the air,it can detect the temperature and humidity of the air and the pollution level,and then the information detected by gathering node will be sent via satellite or Internet to the monitoring center.The application of wireless sensor network mainly depends on the environmental information it can detect,such as temperature,humidity,light intensity,pollution degree and so on.But no matter what kind of environment the wireless sensor network is deployed in,it is necessary to know the specific location information of the wireless sensor network node in order to make the detected information valuable.Therefore,the positioning of WSNs nodes has been a research hotspot of many experts and scholars.The field of wireless sensor network is relatively broad,so that many colleges and research institutes at home and abroad have conducted in-depth research and discussion on wireless sensor network.The main research contents are the design of WSNs node hardware,WSNs nodes positioning algorithm and so on.It is these experts and scholars' continuing efforts to improve the wireless sensor network that makes the application of wireless sensor networks more and more widely.At present,the positioning of most WSNs nodes is based on the location of beacon nodes with known location information in the network.The coordinates of other unknown sensor nodes are calculated by the algorithm.Large scale deployment of beacon nodes is required for larger applications.Therefore,besides the high cost,the maintenance of WSNs also becomes very difficult.In addition,the large-scale loading and positioning module also increases the energy consumption of the sensor node itself,therefore,the power consumption of the sensor node must also be considered.In this paper,Unmanned Aerial Vehicle(UAV)is introduced as an auxiliary tool.Equipped with the global positioning system,it is equivalent to the mobile beacon nodes in the air.In this way,a cooperative positioning model for UAVs and wireless sensor nodes is established.The UAV periodically broadcasts its own virtual beacon information through a preset trajectory,fixed height and speed,and then causes the unknown sensor node to receive the virtual beacon information sent by the UAV.The distance information between the virtual beacon broadcasted by the UAV and the unknown sensor node is acquired by the Received Signal Strength Indicator(RSSI)ranging system.Then,the initial positioning of the unknown sensor nodes is performed by Maximum Likelihood Estimation(MLE).Finally,Square Root Cubature Kalman Filter(SRCKF)is used to precisely locate the unknown sensor nodes.The simulation results show that,with the help of UAV,the accuracy of the node positioning by the SRCKF algorithm is improved,compared with the traditional node-node positioning.In order to make the data more effective,the hardware platform of UAV and sensor node was built,and relevant data acquisition was carried out.Firstly,the communication distance of sensor nodes was tested.Then,the corresponding RSSI values of UAV and sensor nodes at different distances were tested when the UAV was flying at a fixed altitude along a fixed trajectory.Finally,based on the information collected by the current hardware platform,the algorithm is used to test the positioning of unknown sensor nodes in simulation platform.The results show that the algorithm has a small positioning error to some extent.