Ground Stations

The GPS control segment consists of several ground stations located around the world:
• a master control station at Schriever Air Force Base in Colorado
• five unstaffed monitor stations: Hawaii and Kwajalein in the Pacific Ocean; Diego Garcia in the
Indian Ocean; Ascension Island in the Atlantic Ocean; and Colorado Springs, Colorado
• four large ground-antenna stations that send commands and data up to the satellites and
collect telemetry back from them