High Resolution Time Difference of Arrival Using Timestamps for Localization in 802.11b/g Wireless Networks

Localization of mobile devices is an area of much interest in both the commercial, and government sectors. One particular method of localization uses time-difference of arrival (TDoA) measurements from multiple receivers. This can be done using shared timestamps indicating the time of arrival (ToA) among distributed receivers. High resolution timestamps are particularly important to ensure reasonable spatial resolution of the localization method. This paper presents a method to obtain high-resolution time-of-arrival stamps for 802.11b frames based on matched filtering and time-averaged power. This method can be extended to the higher data rates used by 802.11g.