Study On Wifi Indoor Location Techniques Based On Android

With the demand for location based service (LBS) is growing day by day, and the rapid development of wireless communication technology, the wireless positioning technology has become a hot research point. At present, people usually can use the matured GPS and A-GPS positioning systems when they are in outdoor environment. However, the indoor positioning accuracy of these systems is too low to meet the positioning requirement of indoor LBS. WIFI network has become very popular in indoor environment with its features of high-speed communication and convenient deployment. Android system has continued to take more and more market share in the smart phone operating system domain since it is released several years ago, nowadays it’s the most widely used smart phone operating system and the android terminal itself own WIFI connect function also. Fingerprint localization algorithm can reduce the dependence on the signal propagation model which is difficult to define accurately, so it has become a hot research topic among localization technology. Therefore, this thesis focuses on the study and improvement of fingerprint positioning algorithm, designs and implements the WIFI indoor positioning system based on android platform.Firstly, the present research status of the indoor fingerprint positioning technology based on WIFI at home and abroad is analyzed and compared based on lots of related literatures’ reading. Then the principles and characteristics of the relevant technology are introduced and analyzed, including WIFI wireless communication technology, indoor wireless localization technology and fingerprint positioning technology. The factors to influence the localization performance are analyzed based on the characteristics of WIFI indoor fingerprint positioning technology.Secondly, considering the aforementioned key factors to the localization performance, the corresponding solutions are presented. Then the typical DCM algorithms are analyzed, including NN、KNN and WKNN, and an improved method is proposed, then the simulation analysis to these algorithms is done in a MALAB virtual environment, in order to find the optimized parameters and test the performance differences of these algorithms. According to the simulation results, the improved algorithm based on the strongest AP method is selected and adopted in our indoor positioning system.Then, based on the demand analysis on the WIFI indoor positioning system based on Android, the system design scheme is proposed, and the software development environment of the localization system is introduced, the overall architecture and each functional modules of the system is designed. After the design of the system architecture, all the functions of the positioning system are implemented by the programming language JAVA.Finally, an experimental environment for the WIFI indoor positioning system based on Android is constructed, the system test is done with the completed system and the corresponding hardware resources in the experimental environment, including the offline database creation and the online positioning test. The positioning results presented on the localization client can be recorded to make performance analysis to the positioning system.