Patent ID: 8185129
Filing Date: 2012-05-22
Classification: G01S,H04B,H04W

Abstract:
1. A device for estimating the position of itself in response to gathering wireless signal information from WLAN access points (APs), said device comprising: a WLAN radio module for receiving WLAN signals transmitted by WLAN APs in range of said device, wherein the WLAN APs are capable of transmitting on a set of WLAN channels; logic to cause the WLAN radio module to perform a scanning sequence in which the WLAN radio module receives WLAN signals transmitted by WLAN APs in range of said device, wherein the scanning sequence includes an active scanning phase and a passive scanning phase, each of the active and passive scanning phases ending after detecting a sufficient numbers of APs to locate the device; extraction logic for extracting information from said received WLAN signals to identify the WLAN APs; and logic to cooperate with a WLAN-based positioning system to estimate the position of the device based at least in part on the extracted information identifying the WLAN APs in the range of said device; wherein said WLAN radio module is configured to receive signals transmitted by WLAN APs on only a subset of said set of WLAN channels upon a start of the scanning sequence, wherein the subset consists only of WLAN channels that are most commonly used in at least one selected geographic region.