Wi-Fi based indoor positioning system using smartphone

Abstract

With the rapid development of smartphone industry, various positioning-enabled sensors such as GPS receivers, accelerometers, gyroscopes, digital compasses, cameras, Wi-Fi and Bluetooth have been built in smartphones for communication, entertainment and location-based services. Smartphone users can get their locations fixed according to the function of GPS receiver. This is the primary reason why the huge demand for real-time location information of mobile users has been unprecedented in recent years. However, the GPS receiver is often not effective in indoor environments due to the signal attenuation and multipath effects, although it as the major positioning devices have a powerful accuracy for outdoor positioning. This research investigates other built-in sensors and develops methods for improving the accuracy of indoor positioning. Combination with the wireless network, it can be a viable alternative solution for the indoor positioning purposes of the smartphone users. The main advantage of this solution is that it can be deployed with a minimal cost, as no specialized hardware is necessary for setting up the system. However, challenges remain for this solution due to complex indoor environment involved and extensive calibration data overhead. In this thesis, fingerprinting based indoor positioning methods are studied and developed. Field experiments using smartphones and a commercial indoor positioning system (i.e. Ekahau) are carried out in the newly established RMIT indoor positioning laboratory. Then a new indoor positioning system using matching algorithms is designed, developed and tested. Results show that the RMS accuracy achieved using the new system is 2m when 2m spacing resolution is used. The accuracy achieved of the commercial system (i.e. Ekahau RTLS) under an exactly identical environment is 2.79m. The advantages of our system in comparison with the off-the-shelf commercial system are its expendability in further development and easy modification/upgrading of the software system.