Design And Implementation Of Indoor Passive Positioning System Based On BLE

With the rapid development of the Io T technology,more and more application scenarios need to use positioning technology,and indoor passive positioning system is often used in enterprise personnel management.In this thesis,the indoor passive positioning system based on BLE positioning technology is studied.BLE positioning technology has low cost and power consumption,and is easy to implement,however,the directivity of the antenna radiation will lead to a large difference in the RSSI values,once the orientation of the node changes,the RSSI value will change drastically,which will affect the positioning accuracy.Therefore,reducing the influence of the angle fluctuation of RSSI value on the positioning accuracy has become one of the keys to improve the positioning accuracy of the BLE positioning system.In order to reduce the influence of the angle fluctuation of RSSI value on the positioning accuracy,an indoor positioning system based on RSSI angle compensation is designed in this thesis.Firstly,the RSSI values received by nodes in different directions at the same distance are measured to verify the angle fluctuation of RSSI values,and found that the difference between the maximum and minimum RSSI values at a distance of 1m can reach 10d B.Then,the RSSI angle compensation scheme is proposed,which fully considers the relationship between the RSSI value and the angle.In the phase of establishing the ranging models,the ranging models under different angle ranges are established according to the relative angle.The relative angle is obtained through magnetometer,and then select the ranging model under the corresponding angle ranges through the relative angle to calculate the distance information.The ranging experiment shows that the scheme can effectively reduce the ranging error,which can further improve the positioning accuracy.Finally,the static positioning experiment proves that the positioning system designed in this thesis can achieve the positioning accuracy of 1.2671m with a beacon node density of 0.08/m~2,and the angle random positioning experiment proves that the fluctuation range of the positioning accuracy of the positioning system can reach less than 0.3m,which proves that the indoor positioning system based on RSSI angle compensation can not only effectively improve the positioning accuracy,but also can reduce the positioning accuracy fluctuation caused by the change of node orientation,and it can meet the expected index in function and performance.