GPS 2-26, also known as USA 126, is a member of the American constellation of GPS spacecraft and was launched from Cape Canaveral by a Delta-2 rocket. It replaced an aging member of the constellation. Initial orbital parameters were period 723.6 min, apogee 20,365 km, perigee 20,272 km, and inclination 55.03 deg.
The Global Positioning System (GPS) was developed by the US 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. GPS employs 24 spacecraft in 20,200 km circular orbits inclined at 55 degrees. These vehicles are placed in 6 orbit planes with four operational satellites in each plane. There are also four additional satellites orbiting as reserves.
GPS Block 2 was the operational system, following the demonstration system comprised of Block 1 (Navstar 1 - 11) spacecraft. These spacecraft are 3-axis stabilized, nadir pointing using reaction wheels. Dual solar arrays supplied 710 watts of power. They used S-band (SGLS) communications for control and telemetry and UHF cross-link between spacecraft. The payload consisted of two L-band navigation signals at 1575.42 MHz (L1) and 1227.60 MHz (L2). Each spacecraft carried 2 rubidium and 2 cesium clocks and nuclear detonation detection sensors. Built by Rockwell Space Systems for the US Air Force, the spacecraft measured 5.3 m across with solar panels deployed and had a design life of 7.5 years.
GPS navigational location had originally been at 100-meter accuracy for civilian use signals, and at 20-meter accuracy for military use signals. As of 2000 May 01, the DOD voided the intentional degradation of the accuracy for civilian use, and made it on a par with the military accuracy. But it retained the prerogative to degrade the accuracy at selected locations when necessary.
Alternate Names
Navstar 2A-17
USA 126
Facts in Brief
Launch Date: 1996-07-16
Launch Vehicle: Delta II
Launch Site: Cape Canaveral, United States
Mass: 840.0 kg
Nominal Power: 710.0 W