Design And Implementation Of Assets Positioning System In Building Based On WiFi And Bluetooth Signal Fusion

With the development of information and digitization,the demand for location-based services has shown a significant growth trend.Indoors are the places where people stay most,and the storage of all kinds of assets is also mainly located in the indoor environment.The traditional asset positioning management method has the shortcomings of missing information records,cumbersome process,and lagging information.Especially in schools,companies,hospitals,stations,airports and other scenes,it has the characteristics of a large number of types of assets,a large number of room floors,and frequent flow of personnel and assets.Indoor positioning technology creates conditions for asset positioning.If the location of each asset is recorded in real time,it will help to improve the intelligence,informatization,digitalization and convenience of building asset positioning management.At present,the exploration and application of asset positioning using electronic tags have been carried out,but most of them locate assets in local areas,and the positioning effect is poor.In order to improve the speed and accuracy of building asset positioning,this thesis proposes a fusion positioning method based on WiFi and Bluetooth,and uses coarse positioning and fine positioning to achieve asset positioning.The coarse positioning is realized by Bluetooth RSSI ranging positioning algorithm,and the floors and key sub-regions where the assets are located are determined.The precise positioning uses the fingerprint fusion of WiFi and Bluetooth for the location fingerprint method.The fingerprint to be located only matches the positioning fingerprint of the key sub-regions,thus reducing the positioning time and improving the positioning accuracy.The hardware and software positioning platform is designed and built to realize the accurate positioning of building assets.The main contents are as follows:1.This thesis introduces the indoor positioning algorithm based on WiFi and Bluetooth,expounds the principles and problems of different positioning algorithms,and analyzes the feasibility of each method for asset positioning.Considering the hardware cost and positioning accuracy,it is determined to adopt the method of combining RSSI ranging positioning and location fingerprint positioning for building asset positioning.2.According to the characteristics of location fingerprint method and RSSI-based ranging and positioning algorithm,the overall scheme of the building asset positioning system is designed.Completed the hardware equipment selection,design and construction and embedded data acquisition software development,including signal acquisition equipment,positioning terminal equipment,Bluetooth positioning base station and server wireless receiving equipment,realized the positioning data acquisition.3.The positioning algorithm is designed and optimized.Asset positioning is divided into coarse positioning and fine positioning.Before positioning,Kalman filter is used to preprocess the original signal to reduce the influence of signal fluctuation on positioning accuracy.The coarse positioning uses the positioning method based on Bluetooth RSSI ranging.The asset floor judgment algorithm is designed to judge the floor where the asset is located.The location base station selection method based on confidence is designed to determine the base station for each coarse positioning.The purpose is to obtain the floor and key sub-regions where the asset is located.The fine positioning uses the fingerprint of WiFi and Bluetooth fusion to locate the position fingerprint.The positioning fingerprint data in the key sub-regions are selected in the fingerprint database.The generalized regression neural network(GRNN)based on genetic algorithm optimization is used for fingerprint matching to determine the specific location of the assets.In the actual building experiment,the fused fingerprint is better than the single fingerprint,and the average absolute error of positioning is82.93 cm.The positioning effect is good,which is suitable for the positioning of building assets.4.The development of the building asset positioning platform is completed.Based on the Py Charm programming environment,the platform uses Python language,selects the Py Qt5 plug-in for graphical interface editing,and the server-side database uses the relational database MYSQL 5.7.The platform consists of positioning service and functional modules.The positioning service introduces the positioning process of assets,and the functional modules realize the functions of positioning,searching,warehousing and outbound,and historical position view of each asset in the building.