Method and apparatus for determining position location using reduced number of GPS satellites and synchronized and unsynchronized base stations

摘要

A method and apparatus for determining the position of a wireless communication device using global positioning system (GPS) satellites, base stations synchronized to GPS time and base stations that are unsynchronized with GPS time. The unsynchronized base stations are synchronized with one another. Time of arrival information is adjusted to take into account the fact that wireless communication devices that received GPS time information from a base station receive that information biased by the one-way delay that is encountered by the signal that communicates that information to the wireless communication device. In addition, time difference of arrival information for base stations that are not synchronized to GPS time allows the bias between these base stations GPS time to be eliminated.