The global positioning system (GPS) we use in our car and smartphones is operated and maintained by the US Air Force.
Currently, the US Navstar GPS satellite constellation includes a network of 24 primary satellites providing free navigational services to citizens located anywhere on the planet.
Navstar was first proposed as a global positioning satellite system by the Pentagon in 1973. Its first GPS I satellite was launched in 1978.
GPS II satellites were sent into Earth-orbit beginning in 1989, with the last in 2016.
This year, those satellites are in the process of being replaced by GPS III satellites.
The first set of GPS III satellites is named Block IIIA; the following set is called Block IIIF.
GPS III is the future generation Earth-orbiting US GPS navigational satellites.
The first of 10 GPS Block IIIA satellites was launched Dec. 23, 2018, using a SpaceX Falcon 9 rocket. It currently orbits the Earth twice every 24 hours at an altitude of 12,550 miles. and will be undergoing testing for the next 12 months.
The second GPS Block IIIA satellite is slated to be launched in July.
Block IIIA satellites will provide three times better accuracy than current GPS II satellites.
All 10 Block IIIA satellites are expected to be operational by 2022.
Looking ahead, the first of 22 planned GPS Block IIIF satellites is scheduled to launch in 2026, and the last in 2034. Their operating life is yet to be determined.
It’s not publicized much, but since 1980, GPS satellites have been equipped with thermonuclear detonation sensors for detecting nuclear explosions anywhere on the planet. It is called The GPS Nuclear Detonation Detection System.
This information is not classified; but, for the most part, not generally known by the public.
If a nuclear explosion did occur, the data from all satellites observing it would be transmitted to ground stations for immediate processing.
Atomic clocks are recognized as the most accurate time and frequency standard.
Each Block IIIA satellite has a built-in rubidium atomic clock, which is synchronized with the other satellites’ clocks.
There are three GPS segments: space, control, and user.
The US Air Force manages, performs upgrades, and maintains the space and control segments of the GPS.
The space segment is made up of the actively-operating GPS satellites transmitting to Earth their orbiting position and other operating data.
The control segment is comprised of 16 global monitoring stations geographically located around the world. It also includes 11 command and control antennas.
The master control station is located and operated by the 2nd Space Operations Squadron at Schriever Air Force Base in Colorado Springs, CO.
The personnel there ensures the GPS satellites stay in their proper orbit and maintain clocking for correct timing. They also upload navigational data to the spacecraft.
The master control station is backed up by a fully-functioning alternate master control station located at Vandenberg Air force Base in California.
Updates, including software to protect against cybersecurity threats, are regularly made to the control segments of the GPS.
The user segment is the GPS receiver equipment (in our car or on our smart device) we use to acquire data signals from GPS satellites.
The streets and highway information presented on our GPS receiver screen are the output from “moving mapping software,” which is decoding the triangulated satellite signals, calculating, and then displaying our geographical position and travel destination route.
The operating lifespan for the new GPS Block IIIA satellites is 15 years, which is 25 percent longer than prior GPS satellites.
In July, the second GPS Block IIIA satellite, named “Magellan” in honor of Ferdinand Magellan, the Portuguese explorer, will be launched from Cape Canaveral Air Force Station in Florida.
The BeiDou Navigation Satellite System (BDS) is China’s version of our GPS.
April 20, China launched the 44th BDS satellite from the Xichang Satellite Launch Center. The BDS website is http://en.beidou.gov.cn.
Russia’s navigational satellite system is the Global Navigation Satellite System (GLONASS). It has 26 (24 operational) Earth-orbiting satellites providing worldwide coverage. Its website is https://www.glonass-iac.ru/en.
The US government’s official GPS website is https://www.gps.gov.
Dated July 27, 1983. the US Department of Energy Office of Scientific and Technical Information’s 13-page paper, “The Nuclear Detonation Detection System on the GPS Satellites,” can be viewed at https://bit.ly/2Vji5hm.
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