Experience Map Creation by Virtual WLAN Location Estimation

We propose a non-cumbersome automatic location estimation method based on an easily accessible infrastructure: the 802.11 LAN. The method consists of two phases: a map-preparation phase for virtual locations of access point (VLAP) and a target client location estimation phase using these VLAPs. Using the GPS location data of nomadic probe clients as a ground truth and its captured radio signal strengths from already deployed 802.11 access points, we can estimate VLAPs in urban areas. It may be shifted from the real location but could be more reliable since it reflects real radio characteristics. We then estimate the target client location based on the estimated VLAP map in the second phase. Five estimation methods were compared and we obtained a reasonable 23.8 meter mean accuracy using the RSSI and Density- Weighted Centroid method.