Sensor Node Location Algorithm Based On Mobile Beacon And Interference Of Waves

The wireless sensor network is a self-organizing network system composed of a large number of sensor nodes in the monitoring area through wireless and multi-hop communication.Since most of the sensor nodes are randomly placed in the monitoring environment,it is impossible to directly confirm their positions during deployment,and the position information of the node is an important part of the monitoring information,so the sensor node must be located after deployment to accurately position the sensor node.The position information is essential for monitoring activities.The technical challenges facing the positioning of wireless sensor nodes are:1.In real applications,the deployment of sensor nodes is often in large quantities,which requires the hardware cost of the nodes to be as low as possible,which limits the device scale and the size of the sensor nodes;2.Sensor nodes are often unable to supplement energy after deployment,so the node power consumption should be as low as possible,and it is not suitable to perform high-complexity calculations.In order to solve the technical challenges of low cost and low power consumption of sensor node positioning hardware,this paper proposes a sensor node angle measurement method based on mobile beacons and the interference phenomenon of waves,using the phase difference when the beacon moves and interference of waves,which produces the law of constructive interference and destructive interference at unknown nodes.Then the relative angle information is calculated.Based on the angle information,a method of node position estimation based on probability lines is proposed.The main work of this paper includes:1.Propose a sensor node angle measurement method based on mobile beacon and the phenomenon of wave interference.Configure two ultrasonic wave sources at the beacon node to emit waves of the same amplitude and frequency,and one mobile transmitter revolves around the other fixed transmitter.The revolution radius is much larger than the wavelength and is an integer multiple of the wavelength.During the movement of the transmitter,enhanced interference and destructive interference will be continuously observed at unknown nodes.When the mobile transmitter moves to a three-point line with the fixed transmitter and the unknown node,the moving direction of the mobile transmitter is perpendicular to the line connecting the fixed node and the unknown node,so the unknown node will observe the longest time interval of destructive interference,according to the time of constructive interference of the unknown node in this time interval,the initial time and initial angle of the movement of the mobile transmitter,the angle information of the unknown node relative to the beacon node can be calculated.2.A maximum likelihood estimation positioning algorithm based on probability lines is proposed.In this algorithm,the unknown node only needs to know the angle information of two or more beacon nodes and the coordinate information of the beacon nodes to directly calculate the unknown node coordinates.To verify the feasibility of the positioning algorithm,the simulation was carried out;On this basis,the maximum likelihood estimation positioning algorithm based on the probability line is optimized.When the measured angle reaches the correction threshold,the position relationship equation between the unknown node and the beacon node is corrected to suppress error amplification.The effectiveness of suppressing error amplification was verified through simulation experiments.