www.aena.es

The GBAS, Ground Based Augmentation System, will support the precision approach and terminal area RNAV operations stages through the localised deployment of ground stations around the airport.

Thus, unlike current precision approach systems, the GBAS will cover all types of terminal area operations, covering all runways approaches with the installation of a single ground station. As well as providing precision approach capacity for runways currently without it, this will also allow for prevision RNAV operations throughou the terminal area and guided to apron operations.

The GBAS is based on the application of the Differential GNSS Concept, i.e. when a station of reference is installed in a known position on ground, it is able to compare its position with that received through the signals in space from the current GNSS constellations. This relative difference in positions, known as differential corrections, is transmitted to all users operating in a localised area around the station so that they may update their position according to this relative error.

The following can be highlighted as operational benefits expected from GBAS systems:

• To provide precision approach capacity in CAT I in an initial stage and in CAT II/III in the medium-term future to all runway ends of an airport or airports in a nearby area through the use of a single ground facility, which will simplify infrastructure and maintenance tasks and will contribute towards reducing operating costs.
• Provide area navigation (RNAV) capacity, instrumental departures, missed approach guiding and surface movement to operations in the terminal area.
• To carry out new advanced instrumental procedures to allow for a more flexible use of the air space.
• To allow for future 4D navigation, including a precise time reference to add to current 3D navigation.