Quantitative comparison of indoor positioning on different densities of WiFi arrays in a single environment

Abstract

Location Based Services (LBS), which are supported by ubiquitous location finding and positioning information, have become increasingly popular. These services are integrated with various wireless technologies (i.e. cellular, WiFi, and Bluetooth) on mobile devices that establish necessary location information. While each of these technologies contributes to the integration, development and success of LBSs, WiFi has been the most widely employed as an alternative to the Global Positioning System (GPS). Several commercial WiFi-based positioning systems (WPS) are available to the public to extend positioning coverage to places where GPS is unreliable or unavailable; however, these commercial WPSs often fail to deliver GPS-like positioning. The coarse positioning accuracy of commercial WPSs may be caused by unreliable or unsecured databases, which contain the essential WiFi-array information to produce local positioning. Knowing this, the quality of WiFi-based positioning services can be enhanced by improving the quality of a database with well-surveyed and accurate information. The Saskatchewan Enhanced positioning System (SaskEPS) is designed to reduce common errors in WPS. SaskEPS's positioning accuracy and consistency is supported by a thoroughly validated Access Point (AP) database. It has been tested in several buildings at the University of Saskatchewan and successfully provides GPS-like positioning accuracy. Our tests have also begun to elucidate the role of WiFi density in ensuring GPS-like positioning accuracy in indoor spaces. In this paper, we investigate the quantitative relationship between WiFi density and SaskEPS's overall positioning accuracy.