Galileo and EGNOS at the Heart of Future European Air Traffic Management System

The European GNSS Agency (GSA) talks with Aerodays 2015 delegates on how the launch of LPV 200 brings precision landing to even more European airports and helipads and helps air traffic management.

Global navigation satellite systems (GNSS), combined with the precision and robustness offered by the European Geostationary Navigation Overlay Service (EGNOS), will play a key role in the implementation of a European air traffic management (ATM) system. And the development of a harmonised European ATM is the central focus of the European Commission’s SESAR joint undertaking, which is now entering its deployment phase, as showcased at the Aerodays 2015 conference on innovation and research in aviation, held in London from 20-23 October.

“EGNOS and Galileo are involved in all three domains of ATM: communication, navigation and surveillance,” explained GSA Executive Director Carlo des Dorides, speaking at the conference, which is held once during every EU Framework Research programme. “The very accurate time measurement of Galileo will help to synchronise telecom networks, for example. In terms of navigation, Galileo will be central to the multi-constellation concept, which will greatly increase the availability, continuity and robustness of the signal. More so, SBAS (EGNOS) can also be used for surveillance as a positioning source for ADS-B, giving the same level of performance as for secondary radar, with 99.9 % availability.”

Precision Instrument Landing at Low Cost

EGNOS enables localiser performance with vertical guidance (LPV) approaches without the need for costly ground-based infrastructure (e.g. ILS CAT I), usually mandatory for precision instrument landing systems. Since the end of September, the GSA has deployed its EGNOS LPV 200 service, which offers aircraft approaches that are operationally equivalent to ILS CAT I, providing vertical and lateral guidance and with a decision height for a missed approach of just 200 feet. 

“This is particularly interesting for smaller and more remote airports,” explained GSA Market Development Officer Carmen Aguilera. “Normally these airports don’t have enough traffic to justify the investment in ground-based infrastructure. With EGNOS and LPV 200, they can have the same performance, but at much lower cost, enabling them to remain open during bad weather and poor visibility conditions.” 

At present, 202 EGNOS approaches are operational serving 120 airports in 18 countries. The goal is to have 440 procedures operational by 2018.

Continuous Descent Approaches

EGNOS and LPV 200 make curved and continuous descent final approaches possible, which are also core features of a deployed European ATM.  Curved approaches mean that aircraft can avoid built-up areas during landing, reducing noise nuisance, while continuous descent saves fuel – and reduces CO2 emissions - as aircraft are less likely to need to stagger their approach. The expanded trajectory capabilities from take-off to landing offered by SESAR and underpinned by EGNOS will mean more efficient traffic management and flight predictability, with savings in terms of flight time and cost. 

According to Olivia Nunez, ATM expert at SESAR, the AMBER demonstration project at Riga airport showed that, by optimising the flight path, 15 nautical miles can be shaved off the flight path, saving 145 kg of CO2 emissions, as well as reducing noise levels.
The latest EGNOS services are also of great interest to the rotorcraft industry, making helipads more accessible, more of the time. Special Point in Space (PINS) have been developed especially for rotorcraft, interleaving visual segments and instrument segments in departures and approaches. With LPV 200, these can now be implemented down to 200 feet with EGNOS-enabled instruments.

While most modern aircraft are now built to include satellite-based augmentation systems (SBAS) such as EGNOS, the GSA is working with the aviation industry to support the development of cost-effective avionics, to upgrade existing aircraft and perform LPV approaches. In June this year, the GSA launched its second EGNOS adoption avionics call for proposals, with a EUR 6 million budget. “So far it has been very well received,” said Aguilera. “We received applications that amounted to double the budget available and had to turn down some very high quality proposals.”

Towards a Multi-Constellation Environment

“The next EGNOS milestone, scheduled for the end of the decade, will be EGNOS version 3”, explained des Dorides. “This will offer two frequencies – L1 and L5 – meaning that it will be even more robust. It will also overlay not only GPS, as does the current version, but also Galileo, making the multi-constellation concept a reality.” The International Civil Aviation organization (ICAO) in its Global Air Navigation Plan, has recognised the advantages of multi-constellation, multi-frequency GNSS, both technically and in offering significant operational benefits.

One of the additional operational benefits for aviation that Galileo offers is the return link message service in aircraft emergency locator transmitters (ELTs), which confirms receipt of a distress message and greatly facilitates search and rescue operations.

Preparations for EGNOS v3 are now underway, not just in terms of infrastructure, but also the receivers. “At the moment there are no receivers able to process this future version of EGNOS,” explained Aguilera. “We recently launched a call for tenders to develop the prototype receivers that will work with this version, so we are supporting industry to get ready.”

Looking towards the future, beyond the next decade, des Dorides believes that transport will become increasingly intermodal and coordinated: “There will be a paradigm shift,” he said. “Mobility will be a service that is independent of the means - plane, boat or car etc. And here again, GNSS will have an important role to play.”

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