Definition
A satellite-based radio navigation system that provides aircraft with highly accurate position, velocity, and time information anywhere on or near the Earth. The system uses a constellation of satellites broadcasting precise timing signals, which a GPS receiver in the aircraft uses to calculate its three-dimensional position by measuring the time it takes signals to arrive from multiple satellites at once.
Plain English
A navigation system that uses signals from satellites in space to tell the aircraft exactly where it is, how fast it is going, and what time it is.
Context Anchor
Seen on cockpit navigation displays, flight plans, instrument procedures, and air traffic control communications involving navigation.
Derivation
From 'Global' (worldwide), 'Positioning' (finding location), and 'System' (the network of satellites, ground stations, and receivers working together). The name describes exactly what it does: it figures out your position anywhere on the globe.
Why Pilots Care
It enables precise point-to-point navigation, supports modern instrument procedures, and reduces dependence on ground-based navigation aids.
Intuition Check
GPS does not mean the airplane is automatically allowed to fly every GPS-based route or procedure. The installed equipment and the planned use still have to be approved and working properly.
Example Sentence 1
The pilot loaded the destination airport into the GPS and selected the published approach.
Example Sentence 2
During the approach, the GPS provided lateral and vertical guidance to the runway threshold.