1. European initiatives for a new generation of global satellite communication services
Phillipe Renaud and Nikos Fistas
Communications and Surveillance Management EUROCONTROL
This presentation gives an overview of activities underway in Europe to identify the potential of using satellite-based communication systems to complement the VHF systems.
This work is being undertaken by Eurocontrol through its NexSAT project.
Although the initiative is aimed at meeting European requirements, the work is being co-ordinated with other regions of the world directly and through ICAO. The intention is that any new system will be available for use anywhere in the world and will be compatible with ICAO Standards and Recommended Practices (SARPS).
This presentation and the notes was prepared by Phil Platt, Philippe Renaud and Nikos Fistas.

2. Outline of presentation
The potential of satellite communication services
Limitations with current satellite systems
Options for new satellite communication systems
Business and institutional aspects
Timescale
Summary - Conclusions
The presentation will cover the following main topics -
the need for a system outside the VHF band
the limitations of current satellite communications systems
a review of options for a satellite communication system
the business and institutional aspects
the timescale for use of future technologies, and
provide an overall summary of the presentation issues

3. Need for a complementary system
The Aeronautical Mobile Communication Infrastructure needs to evolve to:
Accommodate Traffic growth  Need for additional capacity outside the VHF band
saturation anticipated in Europe even with new VHF technologies
Accommodate new ATS functions increasing flight safety, security and efficiency. These data exchanges will increasingly complement voice communication, which will still be required for immediate emergency and non-routine exchanges.
Air traffic growth is predicted to grow which increases the pressure on communication systems to support Air Traffic Management (ATM). In Europe most communications are currently based on voice in the VHF band (usually based on one channel-per-sector basis). As air traffic grows, more sectors have to be implemented requiring more channels.
From predictions, in about ten years time the VHF spectrum in the core of Europe is going to be totally saturated, despite the implementation of new digital systems such as VDL Mode 2 which are currently being introduced.
Lack of VHF radio spectrum could limit the ability to manage air traffic, resulting in delays on the ground and more frustration for passengers.
Eurocontrol is looking at the potential of voice and data communication systems that operate outside the VHF band to see if they have the ability to complement the VHF systems and handle some of the communication traffic. The systems being considered include new terrestrial systems and satellite systems.

4. Satellite communication technology
Among the candidate systems, satellite-based technologies are being considered due to:
their ability to offer near-global coverage
they can be used where it is difficult or costly to implement a ground infrastructure
spot or regional beams can offer greater capacity where needed (e.g. in high density airspace)
they are suited to air-ground communications and broadcast applications
their capability to complement terrestrial systems (thus reducing pressure on the VHF spectrum)
Satellite communications have the capability to provide communications over wide areas of the world without needing to set up a complex ground network. With geostationary satellites, with an orbit of about 36,000 kms, approximately one third of the Earth’s surface is within covered by the radio beam. Other orbits can be used such as Medium Earth Orbits (MEO) or Low Earth Orbit (LEO). Each type of orbit has benefits and disadvantages.
Smaller beams called spot or regional beams can be used to concentrate power over a smaller area of the Earth’s surface and offer better signal strengths and high communications performance.
Satellite communications systems can support both voice and data communications to aircraft and are particularly suited to broadcast applications. In areas such as Europe, where there is already a terrestrial infrastructure, satellites may be able to complement this infrastructure using spectrum outside the VHF band.
The International Civil Aviation Organisation developed the standards for a satellite communication system which supported the expected needs of aviation from pilot to passenger. The Aeronautical Mobile Satellite Service – AMSS – was born and the specifications completed in 1995.
Satellite communication has now replaced poor quality High Frequency transmissions in some oceanic areas and also facilitated the development of new methods of operation. Applications that were difficult or impossible before satellite communications were available are now bringing benefits to aviation. For example, it is now possible to dynamically re-route aircraft flying over the South Pacific, allowing reductions in flight cost.

5. Eurocontrol NexSAT Project
Mission Statement: to review the capability of satellite systems to complement around the existing communications infrastructure
Main objectives
to review existing and emerging technologies and identify candidates
to work with industry to assist understanding the requirements and to offer appropriate solutions
to co-ordinate with other activities underway in other regions of the world through direct contact
to contribute to the ICAO work on future communication technologies
to meet with Stakeholders to ensure their views direct this work
In November 2002 Eurocontrol initiated its NexSAT project to review activity underway in industry to see if there were potential new satellite communications systems that could be used in Europe.
As mentioned earlier, the need for a complementary system is considered necessary around 2015; this date is based on predicted growth in the VHF band.
Eurocontrol is working with industry to enable them to consider options in possible new systems or enhancements of existing systems. Although the ATS requirements to meet future concepts in Europe - based on ICAO concepts - have been the main focus of work to date, the requirements in other parts of the world need to be considered too if a globally acceptable system is to be implemented. To ensure world-wide involvement the Eurocontrol work is being reported to, and co-ordinated with, activity underway in the ICAO Aeronautical Communications Panel (ACP) working groups particularly WG-C.
In addition to the ICAO activity, Eurocontrol holds regular meetings with Stakeholders through its NexSAT Project Steering Group. Views expressed at these meetings help direct the work and also enable a common understanding to be gained.
The SG meetings are open to anyone interested in the subject, with current participants from Japan, USA and Europe attending. The next meeting will take place in June 2004 in Brussels and everyone is welcome to attend - for more details of the previous meetings please see the project web site - see last slide.

6. From concept to implementation
Research and development
of new techniques
ID 1.1
Emerging or
existing systems
ID 1.2
Early trials/
demo
activity
ID 1.3
Assessment of satellite technologies
ID 1
Alternative
solutions
(if any)
ID 6
Establish commercial
arrangements
ID 8
Equipment development/
modification (Ground and
Aircraft)
ID 9
Consensus on
NexSAT(s)
ID 7
Pre-operational
Service
ID 13
Initial deployment
including flight trials
ID 10.1
Validation ID 10
Confirm Requirements
ID 2
Stakeholder
Requirements ID2.1
Mission
Requirements ID 2.2
Operational
Service
ID 14
Finalise institutional
arrangements
ID 11
Initial Business and Institutional reviews
ID 3
In-Service Support
ID 15
This diagram shows all the high level activity to put a new satellite service into operation.
Eurocontrol is not responsible for carrying out all the activities but the diagram gives an idea of what is required. Currently Eurocontrol is reviewing technologies and confirming the requirements.
Although the technological aspects are important, the business and institutional aspects are equally important,. There is no point in proposing the use of a technology that is unaffordable or if there is a clear indication that solving the up-front investment as well as identifying a beneficial service provision model is not feasible.
It is unlikely that the use of new technology can be made mandatory. The need for a new system (or modification of an existing one) will require a consensus by the Stakeholders - particularly the airlines. The benefits need to be clearly understood and accepted if the system is to be implemented.
Once a consensus on the need and benefits of a new system (or the modification of an existing one) has been reached, a new set of activities has to be completed before an operational service is available. These include safety assessments, commercial arrangements, completion of standards, pre-operational trails, etc.
Safety provisions
ID 12
Initial Safety considerations
ID 4
Standardisation Process
ID 5

7. Current AMSS The current AMSS meets its design goals by -
offering safety and non-safety services to a full range of users sharing the L-band spectrum
However, there is limited deployment due to -
The cost of aircraft installation and avionics
The need to use Large Ground Earth Stations (GES) leading to limited options for communications service provision
Therefore currently AMSS is being used only in low-density and oceanic type airspace
New generation satellite communication systems could offer a higher quality of communication service for use in both low and high density airspace
ICAO developed the standards for a satellite communication system which supported the expected needs of aviation from pilot to passenger. The current Aeronautical Mobile Satellite Service – AMSS specifications were completed in The system is based on the use of large Ground Earth Stations - the aircraft-to-satellite link operates in the L-band ( and – ) and the satellite-to-ground feeder link operates in the C-Band ( GHz). Due to the size of these GESs they are expensive and there are only a few of them around the world. This can lead to long ground connections to get access to the satellite service.
However the AMSS has now replaced poor quality High Frequency transmissions in some oceanic areas and also facilitated the development of new methods of operation through the use of the Boeing/Airbus FANS1/A capability installed in around 1200 long range aircraft e.g. B and A340. Applications that were difficult or impossible before satellite communications were available are now bringing benefits to airspace users and Air Traffic Service Providers in oceanic and low density areas of the world.
The current implementation of AMSS is not fully compliant (FANS and not ATN) with ICAO standards. The performance is not sufficient for use in higher density airspace. Also the installation cost to support both passenger and safety communication is high, due to the need for high gain antennas to offer multi-channel voice and data services. With new techniques or new satellite constellations it seems that a higher level of performance may enable satellite communications to be used in high density airspace, as well as giving benefits in low density airspace.

8. Required Communications Services
High levels of availability, reliability and continuity required for safety and regularity of flight communications
ATS Service
Voice - generally decreasing in use
Data - generally increasing in use
needs to support future ATM operational concepts from ICAO ATMCP in each type of airspace
AOC Service
Voice - meet continuing need for voice communications
Data - support increasing exchange of data messages
A new satellite communications system that supports ‘safety and regularity of flight’ communications (ITU term) services, i.e. ATS and Airline Operational Control (AOC) communications has to support voice and data services with an adequate performance.
The communication service must have a high level of availability, regularity and continuity for both voice and data messages.
In Europe it is predicted that through the greater use of air-ground exchanges voice communications will decline but they must still be available for unusual or emergency situations. The need to replicate the ‘party-line’ for ATS voice exchanges is still under consideration.
Although voice and data are considered as services to be supported by a new system, implementation of the service in different type of airspace will remain an implementation choice based on operational and business considerations.

9. Capacity Requirements
ATM concepts seem to need modest instantaneous throughputs - can be met by a medium rate highly reliable communication system (approx. ~1 kb/s* for data exchanges on average)
Flexibility to increase the communications capacity in specific high density areas through use of regional or spot beams
AOC voice requirements are still being considered but airlines foresee a large increase in data communications
Eurocontrol has carried out a study into the communication requirements needed to meet ATM concepts defined in Eurocontrol strategies around The study - nicknamed MACONDO - identified the communication requirements to support ATM in various types of airspace in Europe ranging from high-density TMAs in the core area to low density en route airspace. Although these were considered to be European scenarios, they are similar to airspace types in other regions of the world. Details of the study can be found at the web site
The study was technology-independent and, showed that some of the most demanding requirements arose in the high density TMAs. However the general requirement appears to be modest at around 1.2 kb/s average per aircraft for data exchanges although the requirements are expected to higher in high density areas.
As the system is expected to support all safety and regularity of flight communications this includes not only ATS requirements but also airline operational control (AOC) communications. The AOC requirements seem difficult to predict accurately - many airlines believe that in the future they will be using applications requiring wide bandwidth communications. AOC applications such as the Electronic Flight Bag are envisaged which will require large amounts of data exchange. However there does not seem to be a consensus on the requirements and each airline tends keep its plans for the future to itself.
IATA and Eurocontrol are trying to develop an overall AOC requirement over the next decade or so. Input from other sources would be welcome.
*Eurocontrol Report ‘Operating Concept for the future mobile communication infrastructure - D2’

10. Reuse and improve
A good infrastructure has been built up so let’s re-use it
GEO Satellites
GESs
Spectrum in L-band
Terrestrial networks
Institutional arrangements
but improve on it by overlaying it with a system with new features.
INMARSAT currently offers global coverage through their Inmarsat-3 satellites operating in the L-band (aircraft to satellite link). These provide coverage through very wide global beams supplemented by narrow regional beams. The INMARSAT service supports all types of aeronautical users. Communication service providers such as ARINC and SITA offer users connection to this satellite service. Many ATSPs use the Inmarsat system to offer ATS services to appropriately equipped aircraft with FANS1/A capability.
The service via the I-3 satellites will be moved to the more powerful I-4 satellites when they are launched next year. The I-4 satellites have multiple regional beams and up to 200 spot beams each. This will allow much faster data services to be provided in the spot beams.
New Generation Satellite Communications systems could make better use of this satellite infrastructure by the use of new techniques. Inmarsat has already enhanced its traditional Aero services to support high data rates - but not for safety-related communications.
This same infrastructure could potentially be used by satellite communication systems using different techniques than those defined by Inmarsat - subject to their agreement.

11. Example regional beam coverage
ARTEMIS
In addition to a global system, regional satellite systems could provide coverage in high traffic load areas of the world. Such regional systems could be used to supplement the communication capacity in high density airspace.
An example regional beam is the European Space Agency’s (ESA) Artemis satellite. Artemis carries three payloads to support navigational, mobile communication and data relay missions over the next 10 years such as -
The provision of voice and data communications between mobile terminals, mainly for trucks, trains or boats in remote areas of Europe and North Africa, as well as on the Atlantic.
Performing a key role within Europe's EGNOS satellite Navigation System by broadcasting enhanced GPS and Glonass signals for use by civilian 'safety critical' transport and navigational services.
The provision of inter-orbit satellite links using advanced S and Ka band frequencies and laser technology.
Other regional systems are available and are expected to continue to be so in the long term. However they have to operate in the appropriate radio spectrum to support AMS(R)S.

12. New Generation Satellite System
Some possible new features -
Low cost avionics
Use of advanced access and modulation techniques
Option to use Ku-band feeder links enabling small GESs
Design in high levels of availability, reliability and continuity required for safety and regularity of flight communications
These features are being investigated in the ESA Satellite Data Link System (SDLS), a project demonstrating the capabilities of satellite com system and investigating issues
If a new satellite communication system is to be developed these are some key areas that could offer improvements -
the cost of the avionics needs to be reduced to achieve a higher equipage rate. A high proportion of aircraft needs to be equipped in Europe if the system is to be successful in relieving pressure on the VHF spectrum
more modern techniques than are used in the current AMSS should help to improvement performance, reduce costs and utilise the spectrum more efficiently
the use of Ku band feeder links will allow smaller GESs to be deployed. However care has to be taken to ensure they operate satisfactorily in heavy rain.
for safety-related communications the system must have measures built in to ensure high quality of service. These measures could include satellite diversity, dual GESs, etc
R&D work underway in Europe is investigating how some of these measures can be implemented in a new system

13. ESA Satellite Data Link System
The ESA SDLS project has been underway for several years
Key features of SDLS include
design to meet to safety and regularity of flight communications
Code Division Multiple Access e.g. to allow multiple access and increase overall efficiency
Ku feeder link
Party-line voice service
support for repetitive short messages
A demonstrator has been developed by Alcatel Space in Toulouse
The ESA SDLS project is investigating the potential of a new satellite system, which should meet many of the requirements for civil aviation safety related communications. The system is tailored to specifically meet these requirements, reducing the complexity of the system design which could reduce the size and cost of the avionics. Specifically, CDMA-based spread spectrum techniques are being explored which can allow a de-centralised control infrastructure unlike current systems based on FDMA. CDMA is the technique used in cellular phone systems and allows multiple signals to exist in the same channel - typically spread over 500kHz to 1MHz. CDMA allows many GESs to co-exist to share a common satellite resource operating in the AMS(R)S L-Band. Feeder links operated at higher frequencies such as Ku-Band open the way to cheaper small aperture antennas - VSATs. Combining both CDMA and Ku band feeder links could enable many more low cost GES to be deployed allowing the capability for users to have a GES at or near their location.
Other features are being developed such as party-line voice. This is a facility to rebroadcast voice messages over a common channel to recreate the situational information available with VHF R/T.
Under ESA funding Alcatel Space is leading a consortium that has built a prototype to demonstrate the capability of a possible new satellite communication system.

14. Other technologies
Existing AMSS (i.e. Aero H and I) are being used today for safety and regularity of communication applications (ATS and AOC) and also for non-safety airline administrative (AAC) and passenger communications (AAC and APC)
Other satellite communication systems that are also being used or are planned include:
Inmarsat aeronautical systems - Swift64, BGAN
Connexion by Boeing
Iridium
Eurocontrol is also reviewing the potential of other satellite communications technologies to see if they could offer the required service.
The existing AMSS is a multi-user system supporting all types of communications. However in today’s world with ever expanding information exchange requirements, modification of existing systems has been undertaken to offer higher data rates e.g. Swift64, BGAN.
Another wide bandwidth system being deployed by Boeing primarily for passenger use could be a candidate but it has not been designed to support safety communications.
The Iridium system has been reborn after financial difficulties a few years ago. At one time it was the main candidate under discussion in ICAO as the Next Generation Satellite service (NGSS).
The next few slides describe these systems in greater detail.

15. Inmarsat systems Aero H,I and L Swift64 BGAN
these are being used to offer ATS (and other services) in several regions of the world
Swift64
introduced to make better use of Aero H infrastructure for non-safety applications e.g. passenger services
BGAN
high data rates (up to 432kb/s) but not designed for safety services
All systems operate in AMSS L-band
Global infrastructure in place now and will continue
INMARSAT in the 1990s defined a range of systems that can support safety-related communications - these are often called the Classical Aero products.
Aero H, H+, I and L are compatible with the ICAO AMSS SARPs. Aero H /H+ and I offer voice and data services. Aero L is a data only system. Aero H/H+ antennas are already installed on 76% of modern, long haul, wide-bodied aircraft, and hundreds of General Aviation and Government/Military aircraft.
Swift64 has been introduced by INMARSAT last year and reuses existing Aero H avionics to support higher speed data (64 kbps) for non-safety passenger use.
Broadband Global Area Network (BGAN) will carry voice and broadband data services (up to 430 kbps) and will be available via the I-4 satellite next year. It is not clear whether this service will support safety communications.

16. Connexion by Boeing
Service was designed to offer a high-speed Internet in the sky
Only targeted at non-safety communications I.e. passenger (APC) and non-safety related airline use (AAC)
Does not operate in ‘protected’ frequency band
obtained a global allocation at WRC03 on a secondary basis
Trials/service underway by several airlines e.g. Lufthansa, British Airways, SAS, All-Nippon Airways,……
Connexion by Boeing (CBB) operates in the Ku band using existing transponders. Forward link data will be up-linked to GEO satellites using the 14 GHz band and then down-linked from the satellite to the AES in the 10/11/12 GHz band. On the return link data will be up-linked from the AES to the satellite using the 14 GHz band and then down-linked from the satellite back to the LES using the 10/11/12 GHz band. This frequency band is designated for use on a secondary basis (agreed at WRC03) and does not have special provisions for safety related communications.
Each forward link carries data from the ground earth station, via satellite, to the airborne terminal at a nominal data rate of approximately 10 Mbps. Multiple airborne terminals share a forward link transponder signal, and each airborne terminal may receive signals from multiple forward links on the same satellite. The return link carries data from the airborne terminal to the ground earth station, via satellite, and may use transponders that are separate from the forward link. Each airborne terminal may transmit at a data rate between 16 kbps and Mbps. Return link transponders will be shared by multiple airborne terminals.
The system was conceived to support passenger and other non-safety applications. However some airlines are considering using the service for some AOC related applications. CBB starts commercial service on regularly scheduled commercial flights in the first quarter of The service will begin on some trans-oceanic and trans-continental flights offered by Lufthansa, BA, Scandinavian Airline System (SAS), Japan Airlines (JAL), and All Nippon Airways (ANA). Full global coverage is anticipated in 2006.

17. Iridium
Iridium offers a truly global coverage with 66 Low Earth Orbiting (LEO) satellites
Iridium is being used by aviation mainly for non-safety applications e.g. AAC and APC
However the FAA is planning to use Iridium to augment its terrestrial UAT network in its Capstone project in Alaska
Iridium offers a voice and data service
The Iridium Satellite System offers complete global coverage of the Earth (including the Polar regions). It achieves this through a constellation of 66 low-earth orbiting (LEO) satellites operated by Boeing. Iridium produces communications services to and from remote areas where terrestrial communications are not available. Iridium currently provides services to the United States Department of Defense and launched commercial service in March 2001.
Iridium was one of the possible so-called Next Generation Satellite Systems (NGSSs) that was being considered by ICAO. Iridium was compatible with the NGSS Standards and Recommended Practices which were adopted by ICAO. When the original Iridium company became bankrupt the NGSS SARPS were not published as there were no candidate systems. When the Iridium company was relaunched in 2001, it offered a non-safety service to all users from the general public to military users. Aviation is using Iridium but mainly for non-safety services. However the US FAA is considering using Iridium to complement the coverage available with their ground-based UAT system. Iridium can provide communications, voice or data, where it is difficult or expensive with a terrestrial system.
General Dynamics is developing a system to allow aviation to make better use of the Iridium communication service but multiplexing many aircraft on one channel.

18. Business Aspects
A ‘new’ Satellite communications system could bring benefits to aviation but it has to be at an ‘acceptable cost’
Need ‘buy-in’ from a range of Stakeholders
airspace users
ATS providers
Communications Service providers
Satellite Service providers
Manufacturing Industry
Although getting the technological aspects of a new satellite communication system correct is important, it is not sufficient to ensure that it is implemented. Equally important are the business aspects. In the design of a new system (or modification of an existing one) there is likely to be a trade-off of better performance and cost. Some design choices could have a major impact on the operating cost - the crucial determining factor for a satellite system being the link budget. These will determine the operating costs including the ‘cost per bit’. The current AMSS is perceived by many to be expensive hence the development of HF data link as an alternative. It is hoped that future satellite communication systems will have much lower cost per bit.
Potential users of a new satellite service have to see the benefits such as improved communications coverage at lower cost leading to better business opportunities. In Europe the business benefit from the ATM point of view is the availability of new communications channels to continue to increase airspace capacity.
For investment to develop a new system (or even modification of a existing system) the commitment of a range of ‘stakeholders’ is required. In particular the airlines will need to be convinced as they will have to make the largest investment; many aircraft will need to be equipped with new avionics and there are associated installation costs. In fact the entire chain from user to service provider has to be motivated to invest.

19. Cost and benefits
Traditional C-B analysis will be needed to give indicative figures but may not be sufficient
Need to identify additional business drivers e.g. benefits of early equipage, better operational control, marketing benefits, etc
A range of business options
Single or Multiple ATSPs contract directly with SSP
Airlines contract directly with SSP
ATSPs and Airlines contract directly with CSP
CSP contract directly with SSP and offer service primarily to support airline operation
As part of the commercial viability the stakeholders need to understand the business benefits to them - one way to do this is via a cost-benefit analysis. The costs involved in implementing a new system have to be weighed against the benefits resulting from that expenditure. Eurocontrol recommends a methodology which many ATSPs follow as part of the investment decision.
From an airline point of view the CBA may not offer sufficient justification to invest. An airline may choose to install equipment to give passengers better facilities than its competitor. Under these circumstances it may be difficult to analyse the business benefits fully. However safety-related communications may be able to be carried over the same system, increasing the business case.
In some circumstances it may also be necessary to encourage airlines to equip with a particular technology to achieve sufficient equipage rates. Measures such as reduced ATS charges or preferential routing for equipped aircraft may be considered. As a last resort mandatory carriage requirements may need to be introduced.
Other business options to be considered include the arrangements between the user of a satellite communication service and its provider. This could be via a communication service provider such as ARINC, or SITA or direct arrangements with the satellite service provider may also be possible.

20. Institutional Aspects
A number of issues have been identified including -
standardisation - ICAO, EUROCAE/RTCA, AEEC, etc
AMS(R)S spectrum availability - guaranteed amount of spectrum needed at the right time
Service level agreements with providers of satellite and communication services
Arrangement between satellite service providers needed if provided by several providers e.g. global and regional spots
Certification and approval
In addition to the business aspects there are a number of institutional ones that also need to be considered.
For a system to be used globally for ATM, standardisation through ICAO is required. In addition Minimum Operational Performance Standards (MOPS) must be developed through organisations such as EUROCAE ( and RTCA ( The MOPS enable manufacturers to test equipment and demonstrate that it meets ICAO requirements. For airline installation a further set of equipment form, fit and function characteristics are usually developed enabling airlines to have the same basic installation (e.g. racking) and to choose from competing equipment suppliers.
Some form of guarantee will be required from the provider to supply the appropriate level of communication service. This is particularly important for safety related communications and this could be reflected in an increase in costs over their ‘standard’ service. Also if several satellite service providers (e/g a global provider and a regional provider) are to be used arrangements to co-ordinate spectrum usage, hand-overs, etc need to be put in place.
The certification of the avionics and approval of the end-to-end service must be considered. Safety regulators will need to be convinced that adequate measures are in place to meet the requirements.

21. Spectrum availability (1/2)
The currently AMS(R)S operates in the L-band (1.5 / 1.6 GHz) where aviation is a privileged user
Radio Regulations give AMS(R)S priority in use of spectrum
The amount of AMS(R)S spectrum needed is dependent on applications (ATS - Voice & Data; AOC Voice & Data)
The L-band is attractive for all mobile communication
propagation characteristics
The currently AMSS support safety and regularity of flights communications (AMS(R)S) in the MSS L-band (1.5 / 1.6 GHz). In this band, which is available globally via the Inmarsat satellites, AMS(R)S has priority in use of spectrum under the Radio Regulations through a Footnote. Currently no other band has provisions to support AMS(R)S although MSS, of which AMSS is a subset, is allowed in other bands.
The L-band is an attractive band for mobile communications as it is not affected by weather conditions like higher frequency bands.

22. Spectrum availability (2/2)
Important considerations
more non-safety related communications could put pressure on safety users
obtaining a world-wide AMS(R)S allocation and deploying systems globally may take some time
important for aviation to use the spectrum
The L-band is an attractive band for mobile communications as it is not affected by weather conditions like higher frequency bands. Consequently more and more non-aviation e.g. land and maritime users are being introduced. This will continue to put pressure on this band. An agenda item at the WRC in 2010 is expected to address this issue by which time it may be too late.
The amount of AMS(R)S spectrum needed is dependent on applications (ATS - Voice & Data; AOC Voice & Data). Initial studies in Europe have shown that the maximum spectrum may be around 4 MHz to support all envisaged ATM applications. This study needs to be refined.
Aviation needs to plan the use of the L-band spectrum into the future so that an expansion in its use can be accommodated. ICAO has work underway to review the spectrum needs of aviation including satellite communications via ICAO ACP WG-F.

23. Next steps
We are finalising the Mission Requirements for the NexSAT service
take into account European AND other region requirements
contributing to the ICAO activity through the Aeronautical Communications Panel
we need inputs from all ICAO regions on
future ATS requirements
future airline operational control communications requirements
input is invited from this region - see Eurocontrol NexSAT web page for contact details
One of the important objectives of the NexSAT project is to get agreement on the mission requirements for the satellite-based communications system. The development of a ‘Mission Requirements’ document is under way. A copy of the document can be found on the Eurocontrol NexSAT project web site - see last slide. Your input is very welcome particularly on AOC requirements which could dominate the design of the system.
In parallel with finalising the requirements, Eurocontrol is working with industry to help them offer cost-effective solutions to meet the requirements not only in Europe but anywhere in the world.
Eurocontrol is also contributing to the ICAO activities on future technologies through the ICAO ACP Working Groups

24. Summary
Satellite communication systems are already providing benefits to airspace users and ATSPs in several areas of the world - usually low density oceanic
New satellite systems could have better performance which may be used to support ATM in higher density airspace such as Europe and in other regions of the world
Spectrum to support new safety-related applications of satellite communications must be protected
EUROCONTROL is refining the requirements and will match these to emerging technologies
Co-ordination and involvement with all regions of the world is vital to achieve a globally harmonised system
The existing AMSS is supporting ATM applications in many areas of the world including the Pacific area, Asia and the North Atlantic. Applications are already providing benefits to airspace users and ATSPs in several areas of the world - usually low density oceanic.
New satellite communication systems or enhancements to existing ones could have better performance which may be used to support ATM in higher density airspace such as Europe and in other regions of the world.
Eurocontrol is refining the requirements and will match these to emerging technologies.
Co-ordination and involvement with all regions of the world is vital to achieve a globally harmonised system.
Spectrum to support new safety-related applications of satellite communications must be protected.

25. Useful websites
This is a list of some relevant web sites on which information relating to satellite communications can be found.
For more information on the EUROCONTROL activities please contact:
Ph. Renaud, tel.: , or
N. Fistas, tel.: ,