Patent ID: 8738043

Claim:
A method for constructing a wireless AP (Access Point) map at a server connected over a network with a user terminal, the method comprising: receiving wireless signal information collected from each of a plurality of user terminals, the wireless signal information including a signal strength of each of a plurality of wireless AP's received by each user terminal; estimating a distance of each of the plurality of wireless AP's by using the wireless signal information; and constructing a wireless AP map by using the estimated distances, wherein the estimating the distance of each of the plurality of wireless AP's includes: selecting a first wireless AP and a second wireless AP from among the plurality of wireless AP's; and selecting wireless signal information for estimating a distance between the selected first wireless AP and the second wireless AP from among the wireless signal information, and using the selected wireless signal information to estimate the distance between the first wireless AP and the second wireless AP, wherein the estimating of the distance between the first wireless AP and the second wireless AP includes: selecting wireless signal information for a first user terminal from among the plurality of user terminals, the first user terminal having a largest value of received signal strength from the first wireless AP or the second wireless AP, estimating a first distance between the first user terminal and the first wireless AP by using a signal strength from the first wireless AP included in wireless signal information of the first user terminal, estimating a second distance between the first user terminal and the second wireless AP by using a signal strength from the second wireless AP included in wireless signal information of the first user terminal, and estimating the distance between the first and second wireless AP's by using the first distance and the second distance, wherein the estimating of the first distance includes assuming that the first wireless AP is positioned on a first circle having the first distance as a radius and the first user terminal as a center to estimate the first distance, the estimating of the second distance includes assuming that the second wireless AP is positioned on a second circle having the second distance as a radius and the first user terminal as a center to estimate the second distance, wherein the estimating of the distance between the first and second wireless AP's includes: determining the estimated distance between the first and second wireless AP's to be an average of distances between the first and the second wireless AP's at all points at which the first and the second wireless AP can be positioned on the first and the second circles.