Definition
A worldwide position, velocity, and time determination system that uses signals from one or more satellite constellations, along with airborne receivers and, where required, augmentation systems, to provide navigation information to aircraft. GNSS encompasses the U.S. GPS, Russia's GLONASS, Europe's Galileo, China's BeiDou, and any approved augmentation such as WAAS, GBAS, or SBAS.
Plain English
A satellite-based navigation system that tells the aircraft exactly where it is, how fast it is moving, and the precise time, by receiving signals from satellites in orbit.
Context Anchor
You will see GNSS in discussions of aircraft navigation equipment, instrument procedures, moving maps, and satellite-based routes or approaches.
Derivation
From 'global' (worldwide), 'navigation' (finding your way), and 'satellite system' (a network of satellites). The name is generic on purpose -- it covers any satellite navigation network, not just the U.S. GPS.
Why Pilots Care
GNSS provides accurate navigation independent of ground-based aids, enabling direct routes, precision approaches, and reliable position data for ADS-B.
Intuition Check
GNSS does not mean only GPS. GPS is one GNSS; GNSS is the broader category that includes GPS and other satellite navigation systems.
Example Sentence 1
The approach plate listed GNSS as a required piece of equipment, so the pilot confirmed the receiver was operating before beginning the procedure.
Example Sentence 2
GNSS signals are required for the aircraft to broadcast its position through ADS-B Out.