TIME DIFFERENCE OF ARRIVAL BASED ESTIMATION OF DIRECTION OF TRAVEL IN A WLAN POSITIONING SYSTEM

摘要

Methods of estimating the bearing of a WLAN-enabled device are provided. A method of estimating a bearing of a WLAN-enabled device includes estimating a speed and geographic location of the device and receiving signals transmitted by an access point, including a first message and a second message. The method further includes accessing a database to determine the geographic location of the access point, determining an actual time of arrival value of the second message, and determining a time difference of arrival value for the second message based on the actual time of arrival of the second message and an expected time of arrival of the second message, which is based on an actual arrival time of the first message. Estimating the bearing of the device is based on the estimated speed and location of the device, the time difference of arrival value, and the location of the access point.