What capability does the Ground Based Augmentation System (GBAS) provide?

The Ground Based Augmentation System (GBAS) is designed to enhance the accuracy and integrity of Global Navigation Satellite System (GNSS) signals used for precision approaches in aviation. Specifically, GBAS enables Category II (Cat II) and Category III (Cat III) instrument landing system (ILS) approaches, which allow aircraft to land in lower visibility conditions compared to standard procedures. This capability significantly improves the safety and efficiency of aircraft operations at airports, especially in adverse weather conditions.

Cat II and Cat III approaches involve more stringent requirements for precision and reliability, which GBAS fulfills by providing differential corrections and integrity monitoring to the GNSS signals. This allows for approaches with decision heights as low as zero feet, facilitating safer landings even when traditional ILS systems might not operate effectively.

Understanding the unique role of GBAS is essential for recognizing advancements in aviation navigation systems and their impact on flight operations. Other options refer to ILS categories not supported by GBAS or outdated navigation systems like VOR and DME, which do not benefit from the augmentation that GBAS provides.