Ch 12. Ground‐Based Augmentation System

Introduction:

The Ground‐Based Augmentation System (GBAS) is a local area differential GNSS (DGNSS) architecture designed to provide navigation services for civil aircraft users during precision approach and landing. The GBAS ground component, illustrated in Figure 12.1, is composed of a number of key elements, including multiple spatially separated multipath‐limiting antennas, a comprehensive integrity monitoring system, and a VHF transmitter to broadcast differential corrections and integrity information to airborne users. The airborne component uses the differential corrections and integrity information to accurately estimate aircraft position (within about 1 m) and to perform the final quantitative assessment of navigation integrity.