Airservices is a government-owned corporation providing safe, secure, efficient and environmentally responsible services to the aviation industry. We manage air traffic operations for around 75 million passengers on more than three million flights every year.

How it works

GBAS corrects GPS errors and provides vertical and horizontal guidance to suitably equipped aircraft for precision approach and landings, initially to Category I (CAT-I) and eventually to Category III (CAT-III) standards.

The GBAS ground station is installed at an airport and consists of:

  • four reference receivers which collect navigation data from GPS satellites.
  • a processor which provides corrections for GPS errors, GBAS-specific information as well as final approach path points
  • a VHF data broadcast unit to transmit digital data to aircraft.

The GBAS transmitted data is received by the aircraft GNSS Landing System (GLS) to improve the accuracy of aircraft positioning and provide guidance for precision approach and landings. The GLS interfaces with cockpit displays and aircraft systems, such as autopilot or flight director. The GBAS guidance information is displayed to the pilot as it would be using an ILS. Pilot actions for GLS approaches also mimic ILS. This simplifies pilot training.