Design And Development Of WiFi Indoor Positioning System Based On Android

The rapid development of wireless networks,communication technologies,and the widespread use of intelligent terminals have made it possible to apply WiFi infrastructure to provide personal and commercial applications for Location-based Services(LBS).However,due to the complexity of the indoor env ironment,most positioning applications are often difficult to provide satisfactory accuracy.Therefore,designing an indoor positioning system that is easy to deploy,simple hardware and accurate positioning is a hotspots of current research.At present,there are various indoor location technologies: optical tracking and positioning technology,bluetooth positioning technology,ultrasonic positioning technology,and infrared positioning technology and so on.Because WiFi positioning technology has the advantages of wide coverage area,high speed information transmission and low implementation cost,this paper designs an indoor positioning system based on WiFi using Received Signal Strength(RSS),which can establish fingerprint database and complete user positioning function in a certain positioning area.Based on the location fingerprinting location method,this paper constructs an indoor positioning framework.The positioning system is divided into offline phase and online phase.In the offline phase the affine propagation algorithm is introduced to cluster the fingerprint data collected offline,which can effectively reduce the matching time in the positioning stage.In the online phase,a two-layer matching method is adopted.Firstly,the classical dete rministic algorithm is used to complete the coarse positioning process.And then the Compress ed Sensing(CS)theory is applied to the positioning in the precise positioning process,which effectively improves the positioning accuracy of the system.According to the indoor positioning framework,this paper completed the design of the indoor positioning system based on Android.Using the idea of functional modularization,two applications,offline acquisition APP and online positioning APP,were designed.The offline acquisition application completes the fingerprint data collection function,the data processing function,and the data storage function;the online positioning application completes the real-time location fingerprinting collection function,the location estimation function,and the map positioning display function.The SQLite database that comes with Android is used as a data transmission bridge for the two applications.In order to verify the positioning algorithm and the location performance of the indoor positioning system,this paper also carried out related experiments.When analyzing the performance of the compressed sensing algorithm,test experiments are carried out from the aspects of algorithm parameters,number of access points,data collection direction and the amount of fingerprint data.The commonly used weighted K nearest neighborhood(WKNN)algorithm is also compared.The results verify that the compressed sensing algorithm can effectively improve the positioning accuracy.In the test and analysis of the positioning system,it is verified that the two applications can correctly complete the corresponding functions.It also shows that the positioning system of this paper can help the user to complete the positioning more accurately when the amount of data collected offline is sufficient.