Indoor Positioning Systems for Different Mobile Terminal Devices

Indoor Positioning Systems for Different Mobile Terminal Devices

With the growing affordability of smartphones, increasing emphasis has been placed on smartphone location-based services (LBSs) aimed at providing users with information about their immediate environments. In addition to identifying user locations, LBSs can be extended to navigation systems and the provision of traffic information. However, the Global Positioning System, which is used extensively, requires an unobstructed line of sight between system satellites and mobile devices. Any obstruction between these components would result in positioning errors. Studies have adopted Wi-Fi access points (APs) in in a Wi-Fi environment for developing indoor systems. Although pattern matching (PM) is a relatively accurate positioning method in such systems, the PM method entails establishing multiple received signal strength indicators (RSSI) databases for different types of mobile devices during the offline phase. The proposed methods do not necessitate creating multiple radio maps for different smartphones, and can thereby reduce the labor and time costs of establishing multiple RSSI databases during the offline phase. Therefore, this study adopted signal differences among wireless APs to establish radio propagation models and mitigate the aforementioned positioning errors, with a maximal increase of 59.6% in positioning accuracy.