Safer and more sustainable airport operations, come rain or shine
As air traffic continues to increase, airports must find new ways to increase capacity and prevent delays, even in the face of adverse conditions such as rain, fog and snow. “When weather reduces visibility, pilots require reliable guidance to help them land,” says Javier de Andrés-Díaz, project coordinator at ENAIRE(opens in new window), Spain’s air navigation service provider. For over half a century, that has been provided by the instrument landing system(opens in new window) (ILS), a radio signal broadcast from the runway to guide aircraft in descent. However, this signal can be distorted while aircraft on the ground pass close to the beacon, meaning that, in poor weather conditions, the operational capacity of the airport is reduced. A ground-based augmentation system (GBAS) offers an alternative. “Whereas ILS creates a single straight 3D path, GBAS allows for greater operational flexibility by serving multiple procedures and runways and even enabling advanced operations – all with a single system,” adds Andrés-Díaz. With the support of the EDGAR(opens in new window) project, ENAIRE is helping develop an improved GBAS – one that provides safety, availability and robustness in all operating conditions and for visibility conditions (known as Category I, II and III Approaches)(opens in new window).
Leveraging dual-frequency signals from multiple GNSS constellations
GBAS augments existing global navigation satellite system(opens in new window) (GNSS) signals by providing precise corrections and integrity data to aircraft in the vicinity of an airport. This ensures accurate and reliable navigation during such critical phases of flight as approach, landing and take-off. The EDGAR project builds on this concept by increasing the number of satellite signals used to calculate an aircraft’s position and flight path, drawing from both Global Positioning System (GPS) and Galileo constellations, known as dual-frequency multi-constellation (DFMC) GNSS. “The result is greater accuracy, higher signal availability and improved robustness against interference and ionospheric anomalous conditions(opens in new window),” explains Andrés-Díaz. Future evolutions of satellite-based augmentation systems(opens in new window) (SBASs), including the European Geostationary Navigation Overlay Service(opens in new window) (EGNOS), will also augment dual-frequency signals from multiple constellations to enhance GNSS navigation across Europe.
Fewer delays and lower emissions
By conducting a wide range of research and validation activities, the EDGAR team helped advance the DFMC GBAS solution. These activities included validating the solution’s performance using GNSS data collected at Tenerife Norte and Ishigaki airports under challenging ionospheric conditions caused by solar flares, which disrupt the normal propagation of GNSS navigation signals. Researchers further analysed the use of Galileo in DFMC GBAS functioning and its benefits, and tested various fallback modes that operate using just single-frequency signals. They also advanced the development of a GBAS system capable of providing Category II service to current GBAS Category I airborne users. With standardisation essential for civil aviation, the project also presented their work to relevant standardisation bodies. By contributing to the technical development of a navigation system that can prevent flight delays, cancellations, diversions and holding times caused by low-visibility conditions, the project is reducing noise levels, fuel consumption and carbon emissions. Furthermore, the project’s use of Galileo supports the development and competitiveness of EU space technology.
