A method and system for synchronizing location finding measurements in a wireless
local area network (WLAN) provides a low cost mechanism for correcting location
measurements within a WLAN location finding system. Multiple location receivers
compute the time-of-arrival (TOA) of a reference transmitter signal, which is generally
a beacon signal. The TOAs are collected and reported to a master unit that contains
stored predetermined position information for the location receivers. The master
unit computes the time-differences-of-arrival (TDOA) between multiple receivers
and computes differences between the measured TDOAs and theoretical TDOAs computed
in conformity with the predetermined position of each location receiver. The deviations
between theoretical and measured TDOAs are collected in a statistical sample set
and Kalman filters are used to produce a model of location receiver timebase offset
and drift over multiple received beacon signals. The filter outputs are used to
then either correct subsequent TDOA measurements for each location receiver, improving
the accuracy of subsequent and/or prior TDOA measurements, or commands are sent
to the location receivers to calibrate the timebases within the location receivers
in order to improve the accuracy of subsequent TOA measurements.