Ground-Based Augmentation Systems Operation in Low Latitudes - Part 1: Challenges, Mitigations, and Future Prospects

Abstract

Ground-based augmentation systems (GBASs) were designed to support civil aviation precision approach and landing with safety and integrity. It has several advantages over traditional navigation aids, allowing airspace usage optimization and reduction of fuel consumption. However, in low-latitude regions such as Brazil, this technology is still not operational due to the strong influence of ionospheric variability. Considering the increased interest in deploying a GBAS station in Brazil along with efforts toward this goal over the last decade, this paper is the first of a two-part series that provides an overview of the key aspects of this technology and the challenges posed when using it in low-latitude regions. The context in which GBAS operates today in midlatitudes is presented along with its fundamental principles and methods of guaranteeing sufficient accuracy, continuity, and integrity for precision operations, particularly those dealing with threatening ionospheric conditions. Finally, the evolution of GBAS to include multiple Global Navigation Satellite System (GNSS) satellite constellations and signal frequencies are discussed with respect to their ability to mitigate ionospheric effects. The conclusion is that the use of these new elements of GBAS seem to be the most viable solution for operating GBAS in low latitudes with high availability.