Integrity monitoring and thresholding-based WLAN indoor positioning algorithm for mobile devices

The Global Positioning System (GPS) works well in outdoor areas, but the satellite signals are not strong enough to penetrate inside most indoor environments. 802.11 wireless LANs (WLAN) signals have been explored for more accurate positioning indoors. Contemporary WLAN positioning maintains the database of location-associated signal fingerprints which is used to identify the most statistically likely match of incoming signal data with those preliminary surveyed and saved in the database. An issue with these systems, however, is the operation robustness. This paper investigates the issue of deploying WLAN positioning software on Android mobile platforms and studies an integrity monitoring technique to account for fading signal characteristics, which are often observed in WLAN networks. Integrity monitoring algorithms exploit redundancy of access points and isolate those with corrupted characteristics to improve system robustness.