Patent ID: 8369264

Claim:
In a Wi-Fi positioning system comprising a reference database of Wi-Fi access point information recorded in a computer-readable medium and containing information about Wi-Fi access points within a large target region, a method of selecting and providing, to at least one mobile client device equipped with Wi-Fi communication logic, a subset of Wi-Fi access point information from said reference database to be used by the client device to estimate its position, wherein the subset is tailored to include information about Wi-Fi access points in a subdivision of the large target region based on the proximity of the client device to the selected subdivision, the method comprising: providing a set of geographical regions, each geographical region being a subdivision of the large target region, and each geographical region containing a plurality of the Wi-Fi access points; selecting at least one relevant geographical region from the set of geographical regions based on the proximity of the mobile device to the relevant geographical region; selecting from the reference database a subset of Wi-Fi access points that are contained in the at least one relevant geographic region; and providing to the mobile client device information from said reference database about the subset of Wi-Fi access points that are located within the at least one relevant geographical region, the information including identifiers for corresponding Wi-Fi access points in the relevant geographical region and including estimated geographic locations of the corresponding Wi-Fi access points so the mobile client device may subsequently estimate its position using the estimated geographic location of at least one of the Wi-Fi access points in the relevant geographical region.