Definition
A satellite-based radio navigation system operated by the United States that provides position, velocity, and precise time information to suitably equipped users anywhere on or near the Earth. It uses a constellation of satellites in medium Earth orbit transmitting timed signals; a receiver calculates its own three-dimensional position by measuring the time it takes signals to arrive from at least four satellites.
Plain English
A network of satellites that lets a receiver figure out exactly where it is, how fast it is moving, and the precise time, by listening to signals from several satellites at once.
Context Anchor
Pilots encounter this term when using panel-mounted GPS units, moving-map displays, route navigation, and some instrument procedures.
Derivation
Global means worldwide, Positioning means working out where something is, and System refers to the full setup of satellites, ground stations, and receivers working together. The name describes exactly what it does: a worldwide system for working out position.
Why Pilots Care
It supplies continuous, accurate position data that supports precise navigation, reduces pilot workload, and improves safety in both visual and instrument conditions.
Analogy
GPS works a little like finding your location by comparing your distance from several known landmarks at the same time. The receiver uses satellites as those known points.
Intuition Check
Do not assume GPS means every navigation display in the aircraft is automatically reliable or approved for every use. GPS is the satellite-based position source; how it may be used depends on the installed equipment, current data, and the operation being flown.
Example Sentence 1
The pilot loaded the approach into the GPS and confirmed the active waypoint before beginning the descent.
Example Sentence 2
During the approach the Global Positioning System provided real-time groundspeed and track information to the pilot.