Ground-Based Augmentation System (GBAS)

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What is the Definition of Ground-Based Augmentation System (GBAS)?

A Ground-Based Augmentation System (GBAS) is a navigation technology that enhances the accuracy, integrity, and reliability of Global Navigation Satellite System (GNSS) signals. It uses a network of ground stations to correct satellite signal errors and transmit precise guidance information to aircraft during approach and landing.

Unlike traditional Instrument Landing Systems (ILS), GBAS supports multiple runway approaches from a single installation and offers flexibility for curved and segmented flight paths. GBAS is critical for precision landings, improved airport efficiency, and enhanced safety, particularly in challenging weather or high-traffic environments.

Key Components of Ground-Based Augmentation System (GBAS)

  • Reference Receivers – Fixed ground stations that continuously monitor GNSS satellite signals to detect errors and variations.
  • Ground Facility – The central processing unit that collects data from reference receivers, generates correction messages, and manages system integrity.
  • VHF Data Broadcast (VDB) Transmitter – Broadcasts correction and integrity information from the ground facility directly to aircraft via VHF radio signals.
  • Aircraft GBAS Receiver – Onboard equipment that receives correction data and refines GNSS signals for accurate positioning during approach and landing.
  • Correction Algorithms – Processes used to compute precise corrections for satellite clock errors, atmospheric delays, and other inaccuracies.
  • Integrity Monitoring – Real-time monitoring systems that ensure the safety, reliability, and trustworthiness of the corrected GNSS signals.
  • Service Area – The geographical coverage zone where GBAS corrections are valid, typically encompassing several runways at an airport.
  • CAT I, II, III Capability – Classification of GBAS precision, allowing different levels of landing approach minimums (e.g., in low-visibility conditions).
  • Power Supply and Redundancy Systems – Ensures continuous and reliable operation of the GBAS ground facility, even in case of outages.
  • Integration with Air Traffic Management (ATM) – Supports seamless communication and coordination between GBAS-equipped aircraft and ground-based air traffic control systems.

What are the Applications of Ground-Based Augmentation System (GBAS)?