Research And Implementation Of Bluetooth RSSI Indoor Positioning Algorithm

With the enhancement of the breadth and depth of people's activities,and the higher demands of production and life,indoor positioning technology has increasingly realistic requirements.With the continuous development of wired and wireless communication technology,indoor positioning has become a hot spot in today's research.The low-power Bluetooth positioning technology has attracted the attention of researchers due to its low cost,low power consumption,and relatively easy implementation.This thesis analyzes and compares different indoor positioning technologies at home and abroad,and studies several typical positioning algorithms,including trilateral positioning method,triangulation method,TDOA,weighted centroid positioning method and received signal strength indicator(RSSI)ranging positioning method.Based on this,an improved weighted centroid Bluetooth RSSI positioning algorithm is proposed,and improvements are made in three aspects:the selection of reference nodes,the transformation of reference node positions,and the optimization of weights.The purpose of this algorithm is to play a smaller distance Influence,reducing the dominant advantage of larger distances,thereby further improving positioning accuracy.The overall implementation process of the positioning algorithm is that the reference node sends out its own information,and the target node receives the reference node information;the Kalman filter is used to process the RSSI signal value to reduce the impact of noise;the target node is estimated according to the RSSI ranging model The distance to the reference node;an improved weighted centroid positioning algorithm is used to calculate the position of the target node.Combined with the iBeacon base station and mobile phone wechat program,an improved Bluetooth indoor positioning system was designed and tested in a laboratory environment.The test environment is equipped with 8 reference nodes and multiple test points.When the terminal device enters the area covered by the iBeacon device,the RSSI values of different signals are obtained,and then the specific position coordinates are calculated through the positioning algorithm in the mobile phone wechat program.The simulation experiment results show that the average positioning error of the improved weighted centroid positioning algorithm is reduced by about 38%.The average positioning error calculated by the Bluetooth RSSI indoor positioning system designed in this thesis is 1.023 m.The simulation results of the algorithm and the actual positioning system are obtained.The result is relatively close,which can meet the indoor positioning needs of general personnel.