Definition
The complete network of GPS satellites in orbit around the Earth that broadcast the signals used by GPS receivers to determine position, velocity, and time. The constellation is arranged so that, from any point on Earth, a sufficient number of satellites are above the horizon at all times to allow accurate position fixing.
Plain English
The full group of GPS satellites circling the Earth. They are spaced out so that, wherever you are, enough of them are overhead at any moment to give your receiver a reliable position.
Context Anchor
Seen in satellite navigation, instrument approaches, and Local Area Augmentation System discussions, where the system depends on usable GPS satellites being in view.
Derivation
Constellation comes from the Latin 'con-' (together) and 'stella' (star). Astronomers use it for a group of stars that form a pattern in the sky. Engineers borrowed the word for groups of satellites arranged in a deliberate pattern around the Earth.
Why Pilots Care
Pilots need enough satellites from the constellation visible to obtain a reliable three-dimensional position fix for navigation and instrument approaches.
Intuition Check
Do not read “constellation” here as a star pattern in the sky. In GPS, it means the group of navigation satellites your receiver can use.
Example Sentence 1
The GPS constellation provides global coverage, so a properly equipped aircraft can navigate by satellite anywhere in the world.
Example Sentence 2
Before an RNAV approach the pilot confirms that the GPS constellation provides adequate coverage along the route.