Transportation · Vol. VII|GPS as a system|1995 (full operational capability)
GPS as a system
1995 (full operational capability)
A constellation of satellites broadcasts time. A receiver that hears four of them can solve for where it is. GPS reached full operational capability in 1995; selective availability for civilians was later turned off. The invention is not a chip. It is a public utility in the sky that shipping, phones, and tractors now treat as air.
U.S. Department of Defense teams; later civil use · Earth orbit / United States
How the mechanism is arranged
How it works
- Each satellite carries an atomic clock and a known orbit.
- The receiver compares time of flight from several satellites.
- The intersection of those ranges is a position on Earth.
Why it mattered
- Made precise location a free (to the user) commodity.
- Rewired logistics, farming, and everyday meeting-up.
- Created a dependency: jam the sky, and much of the ground slows.
Who turned the wheel
What it unlocked
For further study
- U.S. GPS.gov historical notes. Milestones.
- Parkinson et al. GPS papers. Architecture.
Check
Why does a GPS receiver need time as much as it needs space?