A sector-based campus-wide indoor positioning system

The purpose of this paper is to describe a campus-wide indoor and outdoor positioning system developed at the School of Surveying and Spatial Information Systems at the University of New South Wales, Sydney, Australia. The system uses a Wi-Fi positioning technique known as `fingerprinting' to locate users indoors, and GPS to locate users outdoors. Fingerprinting first requires the building up of a database of signal strengths from different Wi-Fi access points taken at different points across the area of interest. Then, the user scans the signal strengths in the wireless network and sends the data to the database, which will find the closest match, and return the likeliest location of the user. Our work investigates different approaches to database generation and fingerprint matching, and their impact on system performance. We find that reducing the time for the survey phase by half does not impact significantly on the final accuracy of the system. The system is also tested outdoors to investigate whether Wi-Fi can challenge GPS for outdoor positioning, and we find that Wi-Fi can match, and sometimes outperform GPS in terms of accuracy.