Global Positioning System (GPS) was developed by the U.S. Department of Defense to provide all-weather round-the-clock navigation capabilities for military ground, sea, and air forces.
Since its implementation, GPS has also become an integral asset in numerous civilian applications and industries around the globe, including recreational used (e.g., boating, aircraft, hiking), corporate vehicle fleet tracking, and surveying.
They used S-band (SGLS) communications for control and telemetry and Ultra high frequency (UHF) cross-link between spacecraft.
Built by Rockwell Space Systems for the U.S. Air force, the spacecraft measured 5.3 m across with solar panels deployed and had a design life of 7.5 years.
[7] Following decommissioning, it was subsequently placed in a disposal orbit approximately 1000 km above the operational constellation on 21 September 2015.