To address the need for an apparatus and method of economically synchronizing base sites (110-113) in wireless communication systems, the present invention provides a GPS-based solution for synchronizing slave sites (111-113) to a regional master site (110). In general, the master site reports to the slave sites information indicating the timing variance of GPS satellites (101-105). The slave sites then use this information in combination with information they collect from the same satellites to periodically resynchronize their clocks to the master clock.