Definition
A satellite-based precision approach and landing system that uses GPS signals, augmented by a ground-based station at the airport, to guide an aircraft along a precise lateral and vertical path to the runway. The ground station broadcasts correction data and approach path information to the aircraft via VHF data link, allowing the aircraft's onboard equipment to fly an approach comparable in accuracy to an Instrument Landing System (ILS).
Plain English
A landing system that uses GPS, made more accurate by signals from a small ground station at the airport, to guide an aircraft down to the runway in poor visibility.
Context Anchor
You may see GLS listed as an available instrument approach for a runway, or hear it discussed when comparing satellite-based landing guidance with older runway-based systems.
Derivation
‘Global’ refers to the use of the Global Positioning System (GPS) satellites that cover the whole earth. ‘Landing system’ signals that it serves the same role as older systems like ILS — guiding the aircraft to a safe touchdown.
Why Pilots Care
It enables reliable precision landings at more airports without traditional ground-based ILS equipment, increasing safety and operational flexibility.
Intuition Check
Global does not mean every airport has this landing system. In this context, it means the system is based on satellite navigation, with local corrections needed for the specific runway approach.
Example Sentence 1
The crew briefed the GLS approach to runway 27, noting the decision altitude and the required avionics setup.
Example Sentence 2
GLS guidance allowed the flight to continue the approach when the ILS was out of service.