In 2014 a small geostationary orbit satellite could be launched to help modernise air traffic management in Europe. The satellite would begin deployment of a constellation that will deliver ATM communications for the European Civil Aviation Conference area that spans from Iceland to Azerbaijan.

Industry has until 4 May to submit tenders for phase B of Iris, the European Space Agency's air traffic management via satellite project. While aircraft satellite communications have been used for many years they have mostly addressed non-safety-critical communications such as passenger telephone calls and internet connectivity.

By 2020 global air travel is expected to double, resulting in increasing congestion in the air and on the ground and a new requirement for an independent safety-critical air-to-ground link.

Satellite 
© ESA
A small GEO spacecraft like this ESA concept for such a satellite could be used for Iris

With the support of the European space industry and Eurocontrol, air navigation service providers and national space agencies, ESA, through Iris, is studying satellite communications in its collaboration with the European Union's Single European Sky (SESAR) programme.

The European Commission has already set targets for such a satellite system. ATM must be 50% less expensive than current services, it must be able to handle a threefold increase in communication capacity, help improve safety by a factor of 10 and reduce the environmental cost by at least 10%. "When coupled with navigation systems like [the European Union's] Galileo, satellite communication can even contribute to optimising aircraft trajectories," says ESA. For safety and cost ESA says that future avionics could be integrated and standardised with Iris.

What is Iris?

Iris, named after the mythological personification of the rainbow and messenger of the Greek gods, is the European Space Agency's programme for air traffic management via satellite.

It is an ESA telecommunications department project under its Advanced Research in Telecommunications Systems (ARTES) programme and is known as ARTES 10.

The Iris programme is divided into three phases. The first phase led up to the 2008 ESA member states' ministerial council meeting. Headed by Thales Alenia Space and EADS Astrium, it examined Iris's requirements and what is needed to bridge the gap between existing standards for satellite and aviation telecommunications.

The second phase will start in mid-2009 and include system development. Industry has until 4 May to submit bids for this phase.

Phase three is planned to start in 2012 and, if approved by the 2011 ministerial council, will support in-orbit verification and certification of the pre-operational system and technical support for deployment of the full system.

Iris's phase one saw two trade studies, one led by Thales Alenia Space, and the other by EADS Astrium. Issued to ESA in the first quarter, Thales's preliminary definition begins with the 2014 small GEO satellite deployment for technology demonstration purposes. It is to be followed by 2020 by at least two larger geostationary orbit spacecraft, for redundancy and to deliver the service. Astrium had a similar system that employed GEO spacecraft with on-orbit spares. Iris's GEO spacecraft would provide L-band mobile communications between the satellites and aircraft and Ku-band fixed links between the spacecraft and ground stations.

Iris's phase B is to start by July this year. It will investigate L-band antenna designs, beam forming networks and scheduling co-operation with SESAR.

"Our role is only to provide what aviation wants. By 2011 we [Iris] will have a defined system. Then we can move on to phase C and D [to design the spacecraft]," says ESA's Iris programme head, Nathalie Ricard. She says that the challenge for air traffic satellite telecomms is that ATM datalinks have entirely different requirements to the telephony and internet connectivity that has previously characterised air-to-ground via space aviation communication.

Funded with €35 million ($45.4 million) up to 2011, the final cost of Iris will not be known until the number of satellites and their capability is decided.

Whatever is decided, Ricard says, a satellite will be needed in orbit by 2014 at the latest to enable airlines' aircraft-based Iris terminals to be certificated and for the companies to roll out the technology across their fleets to ensure the system is fully operational in 2020.

Ricard presented the project's results to date at a conference in March that included 80 countries, including Japan, as well as the International Air Transport Association, the US Federal Aviation Administration and the International Civil Aviation Organisation.

Ricard's team is already talking to Canada and Russia about possible compatibility between Iris's satellites and those countries' spacecraft that would be in highly elliptical orbits, which would be capable of providing the same service to aircraft in extreme northern latitudes. Because Iris spacecraft are in GEO, they are very close to the horizon for the purposes of serving aircraft flying over, say, northern Sweden.

Whether this satellite-enabled ATM service will be public or private is, says Ricard, "a matter of debate". She points out that as most European countries' air traffic control are public services, it would be deemed safety critical, it would be a monopoly and the operator would have to be certificated, which is a liability issue Ricard thinks may be an obstacle for private companies.

Source: Flight International