GPS at Schriever SFB

The Global Positioning System (GPS) is the world's only global utility.
Operated by the dedicated men and women of the 2d Space Operations Squadron (2 SOPS) assigned to PNT Delta Provisional and headquartered at Schriever Space Force Base, Colorado. GPS is also the Department of Defense’s largest military satellite constellation. 2 SOPS performs the command and control mission for the Global Positioning System satellite constellation. Uses of GPS include precise timing for financial transactions, the electrical grid, search and rescue, water systems, petroleum, communications, farming, recreation, and both military and commercial aviation.

GPS Master Control Station
The Global Positioning System Master Control Station (MCS) provides a single center of excellence for user support and GPS constellation operations. The GPS MCS, located at Schriever Space Force Base, Colorado, provides  the U.S. government, allied, and partner GPS users worldwide with anomaly reports and other information 24 hours a day, seven days a week. 2 SOPS also owns and can operate from the Alternate Master Control Station, located at Vandenberg SFB, CA.

The Global Positioning System is a constellation of orbiting satellites that provides positioning, navigation, and timing (PNT) data to military and civilian users globally. GPS provides nuclear detonation detection information to the Air Force Technical Application Center and is the Department of Defense’s designated representative in the interagency Crucible Process to identify and respond to GPS interference in the United States and its territories. The system is operated and controlled by PNT Delta Provisional, located at Schriever Space Force Base, CO.

GPS satellites orbit the earth every 12 hours, emitting continuous navigation signals. With the proper equipment, users can receive at least four satellite signals to calculate time, location, and velocity. The signals are so accurate, time can be figured to within a billionth of a second, velocity within a fraction of a mile per hour and location to within 100 feet. Receivers have been developed for use in spacecraft, aircraft, maritime vessels, land vehicles, and precision-guided munitions, as well as for hand carrying.

GPS provides 24/7/365 navigation services including:

  • Extremely accurate, three-dimensional location information (latitude, longitude, and altitude), velocity (speed and direction), and precise time
  • A worldwide common grid that is easily converted to any local grid system
  • Passive all-weather operations
  • Continuous real-time information
  • Support to an unlimited number of users and areas

The GPS constellation is nominally designed and operated, consists of six orbital planes, with a minimum of four satellites per plane.

GPS satellites are launched from Cape Canaveral Space Force Station, FL., into nearly circular 11,000-mile altitude orbits. While circling the earth, the systems transmit signals on two different L-band frequencies. The design life of a GPS satellite ranges between 12 and 15 years. 

The GPS Master Control Station (MCS), operated by PNT Delta Provisional at Schriever SFB, CO, is responsible for monitoring and controlling the GPS satellite constellation. The GPS-dedicated ground system consists of six U.S. Space Force dedicated monitor stations (MS) and four ground antennas (GA) located around the world as subordinate units to 2 SOPS. The MSs use GPS receivers to passively track the navigation signals on all satellites. In 2007, GPS added 10 more shared monitor stations (part of the National Geospatial-Intelligence Agency (NGA) network of monitor stations) increasing the overall accuracy of the system to all users. Information from the MSs is processed at the MCS to update the satellites’ navigation messages to include commanding (telemetry). In 2023, NGA added an 11th station, yielding 17 total NGA and Space Force MSs.

The PNT Delta Provisional is working to enhance many of the capabilities provided by the current satellites and user equipment. In April 2014, the pre-operational broadcast of navigation messages began for additional civil signals (L1C, L2C and L5). Additionally, the next generation of satellites will provide increased signal accuracy and reliability to operate through a contested environment and interoperability with other navigation constellations such as the European Union’s Galileo. Applications such as mapping, aerial refueling and rendezvous, geodetic surveys, and search and rescue operations will benefit from these enhancements.

GPS capabilities were put to the test during the U.S. involvement in Operations Desert Shield and Desert Storm. Allied troops relied heavily on GPS to navigate the featureless Arabian Desert. During operations Enduring Freedom, Noble Eagle, and Iraqi Freedom, GPS contributions increased significantly. During Operation Iraqi Freedom, the GPS satellite constellation allowed the delivery of 5,500 GPS-guided Joint Direct Attack Munitions with pinpoint precision that reduced collateral damage. This was almost one-fourth of the total bombs and missiles coalition forces released against Iraqi targets. GPS continues to fill a crucial role in air, ground and sea operations guiding countless service members and equipment to ensure they are on time and on target.

The U.S. Space Force’s Space Systems Command at Los Angeles SFB, CA., acts as the executive agent for the Department of Defense for acquiring GPS satellites and user equipment.

General Characteristics
Primary Function: Positioning, navigation, timing, and velocity information worldwide
Weight: Block IIR/M, 4,480 pounds (2,217 kilograms); Block IIF, 3,758 pounds (1,705 kilograms); Block III vehicles 1-10, 5,003 pounds (2,269 kilograms)
Date of First Launch: 1978
Date Constellation Operational: April 1995 (at Full Operational Capacity (FOC))