The European Geostationary Navigation Overlay Service (EGNOS) provides clear benefits to the business aviation sector. With many business aircraft not specifically catered to by current air traffic management systems, more often than not they find themselves shut out of many key airports.
This is particularly true as Europe’s skies continue to become more and more crowded. As air traffic continues to grow, smaller airports must make themselves accessible at all times–something that cannot be done when relying solely on nonprecision approaches.
EGNOS improves accuracy of position measurements by sending out signals that correct GPS data and provide information on reliability. Via its network of nearly 40 reference stations located in more than 20 countries, the system picks up signals from GPS satellites that are then processed in master control centers to determine the accuracy of the original signals based on such factors as electrical disturbances in the atmosphere. The data is incorporated into EGNOS signals and sent to its geostationary satellites, which then relay the signals back to EGNOS-enabled receivers.
“In business aviation, EGNOS is increasing accessibility to smaller airports and enhancing safety via increased situational awareness,” said Carlo des Dorides, executive director for the European GNSS Agency (GSA). “Fostering further GNSS adaptation is a key focus of the GSA; in particular, creating tools and methods to enable LPV [localizer performance with vertical guidance] implementation to small airports.”
Cleared for Landing
Business aircraft depend on access to small and medium-sized airports. According to recent Eurocontrol data, 66 percent of business flights occur between city pairs that lack daily commercial service. However, depending on the airport, landing at one often comes with new challenges such as approach trajectories. For example, many of these airports are located in demanding environments like mountainous areas that require complex approach trajectories.
More so, airports located near or within major cities are obligated to develop complex approaches aimed at avoiding heavily populated areas. On top of this, many of these airports lack the high-tech equipment found in commercial airports. For example, ILS navigation aids are often limited or simply nonexistent, increasing the risk of a flight diversion.
Because APV [approach procedures based on vertical guidance] using SBAS, or LPV approaches, do not require ground equipment, they have the potential to enable near-precision approaches for all airports–greatly increasing their attractiveness for business aviation.
“When you talk about safe access to regional airports without the need for expensive ground instruments, then satellite navigation systems become a very compelling option for business aviation,” said Fabio Gamba, CEO of the European Business Aviation Association. “We have EGNOS, so let’s use it in the best possible way.”
To illustrate some of the advantages, consider that LPV approaches are designed in Europe with a 250-foot decision height, although this figure could decrease to 200 feet in the near future. By comparison, the average decision height for nonprecision approaches in the U.S is 470 feet.
In addition, as the final approach segment of a LPV approach is entirely virtual and not linked to a ground-based guidance system, using different approaches on the same runway end for different aircraft categories is a real possibility.
Better Access in Europe
Today, GNSS penetration in the global aviation market is more than 80 percent, and shipments of EGNOS-enabled devices are expected to dominate the market. Last year, the penetration of SBAS-enabled units in equipped aircraft reached 30 percent in the regional, business and IFR general aviation sectors, and it is expected to increase in the coming years with new ICAO recommendations.
In Europe, ICAO recommends deploying APV approaches on all runways by 2016, and EGNOS (Booth 6222) is included in the regional performance-based navigation plan. In fact, EGNOS-enabled receivers are widely available thanks to its compatibility with the proven U.S. WAAS system, with more than 55,000 aviation receivers already in use. EGNOS signal may be used for approaches employing a certified receiver, flight management system and SBAS procedure. Certified since 2011, the EGNOS signal is also free to use.
This compatibility with other SBAS is a significant advantage. “The compatibility and interoperability between SBAS and neighboring systems is necessary to ensure proper service delivery to end users and to maximize the benefits of SBAS technology,” said Jean-Marc Pieplu, head of the EGNOS exploitation program. “It impacts not only the design of system evolution toward multi-frequency and multi-constellation service provision, but also day-to-day operations.”
SBAS are delivering regional signals and services over coverage areas that are mutually complementary or overlapping. For example, EGNOS and its Russian partners are addressing the compatibility between the EGNOS signal transmitted by Inmarsat 3F2 and the new signals transmitted by Luch 5B. “Cooperation between SBAS service providers is thus a key enabler for all SBAS and a clear objective for EGNOS as it is in the best interest of users,” added Pieplu.
Overall, EGNOS is a success, yet it has not reached its full potential. This is due in part to long equipment cycles in avionics and barriers to market adoption caused by fragmented regulations at the national level.
Yet every day EGNOS is delivering the services it was designed for with a remarkable level of stability and performance. Today more than 100 airports are already benefiting from EGNOS and more than 400 runways plan to use EGNOS-enabled approaches by 2018. Future activity will focus on supporting countries in identifying the airports that can most benefit from EGNOS, map them in the national PBN plan and assist LPV operational implementation.