U.S. Satellite navigation systems, programs, and manufacturers
| Program | Owner | Years active | Key technology capabilities |
|---|---|---|---|
| Vanguard | U.S. Navy | 1955-1959 | Used solar cells to power radio transmitter, collected novel information about satellite orbits as well as geophysical characteristics of Earth |
| Transit | U.S. Navy | 1959-1996 | Established orbital patterns and predictions |
| System 621B | U.S. Air Force | 1963-1973 | Developed “pseudo-random noise” signal to resist jamming |
| Timation | U.S. Navy | 1964-1973 | Developed passive-ranging technique using high-stability clocks and time reference for positioning |
| NAVSTAR GPS | U.S. Air Force, JPO | 1973-present | Installed atomic clocks onboard GPS satellites; delivered civil and military signal; ground, control, and space segments maintain timing integrity |
| GPS Satellite | Launch | Key Technology | |
| Block | Manufacturer | Period | Capabilities/Improvements |
| I | Rockwell International (Boeing) | 1978-1985 | Design life of 5 years, two L-band navigation signals, served as concept testing series |
| II | Rockwell International (Boeing) | 1989-1990 | Nuclear detection sensors, designed to operate for 14 days without contact from control segment |
| IIA | Rockwell International (Boeing) | 1990-1997 | Durability improvements, designed to operate for 180 days without contact from control segment; 7.5-year design lifespan |
| IIR | Lockheed Martin | 1997-2004 | Replacement satellites for Block II, 7.5-year design lifespan |
| IIR-M | Lockheed Martin | 2005-2009 | Included military signal (M-code) and new civil signal (L2C), 7.5-year design lifespan |
| IIF | Boeing | 2010-2011 | Included third civil signal (L5), inertial navigation systems, 12-year design lifespan |
| IIIA | Lockheed Martin | 2014 onwards | Include a fourth civil signal (L1C), higher broadcasting power, navigation enhancements, improved interoperability, greater jamming resistance, 15-year design lifespan |
| Program | Owner | Years active | Key technology capabilities |
|---|---|---|---|
| Vanguard | U.S. Navy | 1955-1959 | Used solar cells to power radio transmitter, collected novel information about satellite orbits as well as geophysical characteristics of Earth |
| Transit | U.S. Navy | 1959-1996 | Established orbital patterns and predictions |
| System 621B | U.S. Air Force | 1963-1973 | Developed “pseudo-random noise” signal to resist jamming |
| Timation | U.S. Navy | 1964-1973 | Developed passive-ranging technique using high-stability clocks and time reference for positioning |
| NAVSTAR | U.S. Air Force, | 1973-present | Installed atomic clocks onboard |
| Launch | Key Technology | ||
| Block | Manufacturer | Period | Capabilities/Improvements |
| I | Rockwell International (Boeing) | 1978-1985 | Design life of 5 years, two L-band navigation signals, served as concept testing series |
| Rockwell International (Boeing) | 1989-1990 | Nuclear detection sensors, designed to operate for 14 days without contact from control segment | |
| Rockwell International (Boeing) | 1990-1997 | Durability improvements, designed to operate for 180 days without contact from control segment; 7.5-year design lifespan | |
| Lockheed Martin | 1997-2004 | Replacement satellites for Block II, 7.5-year design lifespan | |
| IIR-M | Lockheed Martin | 2005-2009 | Included military signal (M-code) and new civil signal (L2C), 7.5-year design lifespan |
| Boeing | 2010-2011 | Included third civil signal (L5), inertial navigation systems, 12-year design lifespan | |
| Lockheed Martin | 2014 onwards | Include a fourth civil signal (L1C), higher broadcasting power, navigation enhancements, improved interoperability, greater jamming resistance, 15-year design lifespan |
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