If you’ve ever used mapping applications, or other similar navigation applications, you’ve used GPS!
Global Positioning System (GPS) is one of a few Global Navigation Satellite Systems (GNSS) that provide positioning, navigation, and timing services.
With at least four satellites, we can obtain the exact position of a receiver at any given time.
How does GPS work?
- Satellite sends signals from space to the receiver and measures the distance between them.
- In a process called trilateration, three satellites are used to obtain the coordinates of the user.
- To sync the coordinates, there is one last unknown: time. As GPS receiver clocks are not as precise as the atomic clocks on the satellite, this clock bias needs to be solved. With at least four satellites, all four unknowns are solved.
Aside from GPS, which is run by the United States government, other GNSS include Russia’s GLObal NAvigation Satellite System (GLONASS), Europe’s Galileo, China’s Beidou, Japan’s Quasi-Zenith Satellite System (QZSS), and the Indian Regional Navigation Satellite System (IRNSS).
Beyond positioning, GPS can be used to obtain other measurements, such as sea-level.
To learn more about GPS, visit our FAQ: What are the uses of GPS?