1. Presented by Philippe Renaud
Most Probable Satellite Communications Operating Concept for ECAC and other regions of the world
Presented by Philippe Renaud
Prepared by Phil Platt
ICAO AMCP WG-C
27-30 May 2002

2. European Civil Aviation Conference (ECAC) Member States

3. Communications Problems
In certain parts of the world (e.g. Europe) air traffic growth will outstrip communication resource in the VHF band.
New technologies are being considered in the timeframe of to complement VHF systems
Satellite communications could be a possibility but only with improved performance over current AMSS
A lower cost satellite communication system would benefit many other areas of the world too

4. Predicted Traffic growth in Europe
This diagram shows the predicted number of IFR flights per day in 6 by 10 miles boxes in the year 2020.

5. Worldwide air traffic
This map is based on the fuel used by aircraft as part of a NASA study (1992).
Note there is little traffic no traffic over the South Pole

6. Inmarsat Global beams

7. MTSAT - Japan

8. European spot beam

9. Limitation of current AMSS
Designed to meet full range of users leading to more complex system design
Shared use of spectrum between safety and non-safety services
Cost of aircraft installation and avionics
Large GESs leading limited options for communications service provision
Quality of communication service - transfer delays
Communication costs

10. A new satellite system ? Oh no not more technology !
Haven’t we got enough satellite communications systems e.g.
Inmarsat Aero systems H, H+, I, L, C, Mini-Aero, Swift64
MTSAT (Japan)
Boeing Connexion
Iridium
Globalstar
……….

11. Safety related communications
Yes there are many satellite technologies around but they are designed to support shared use
Some support AAC, APC - some may support AOC and ATSC (e.g. Aero H)
No system supports only AMS(R)S
Previous experience has shown that reliance on a shared business case can cause problems
Where safety and regularity of flight communications are to be carried by a communications system specific measures must be put in place to safeguard them

12. Requirements
High levels of availability, reliability and continuity required for safety and regularity of flight communication
ATS
Voice
Data
AOC
Ranked on priority basis

13. ATSC Voice ATSC voice is main form for executive control today
There will be increased use of data link in the future but voice will be required at least in the foreseeable future
ATSC use of data link requires new investment in ATS system on ground - voice is already there.
VHF RT is the main means of communications in higher density airspace where there is a ground infrastructure

14. ATS Data Link Services ATC Communications Management Service (ACM)
Departure Clearance Service (DCL)
ATC Clearances and Information Service (ACL)
Controller Access Parameters Service (CAP)
Downstream Clearances Service (DSC)
Pilot Preferences Downlink Service (PPD)
Flight Plan Consistency Service (FLIPCY)
Dynamic Route Availability Service (DYNAV)
Dynamic Route Availability Service (DYNAV)
Data Link Operational Terminal Information Service (D-OTIS)
Data Link Runway Visual Range (D-RVR)
Data Link Logon (DLL)
Common Trajectory Co- ordination (COTRAC)
Data Link SIGMET Service (D-SIGMET)
System Access Parameters Service (SAP)

15. AOC Applications Voice Data Link
assumed to be continued to be required although expected to decline
Data Link
Flight Operations - a few examples of safety and regularity of flight applications
Access to Flight Information services (Weather, NOTAM…)
Weight & Balance
Performance Data
Maintenance
Aircraft condition monitoring

16. New Satellite System (1/2)
Desirable Features
Those identified in NGSS SARPs including
Tailored requirements - safety and regularity traffic only i.e. priority 1 to 6 in Article 44
dedicated AMS(R)S spectrum
Replicate and improve on existing systems
Voice - VHF RT like with party-line and quick access
Data - point-to-point and broadcast
Optimised channels
tailored to meet the AMS(R)S requirement only until at least 2020 and possibly longer
Designed to provide required level of performance
use redundancy in critical communications path

17. New Satellite System (2/2)
Desirable Features
Ground Earth Station
able to reuse existing AMSS infrastructure wherever possible
allows possibility to use GESs with smaller antennas
greater flexiblity in deployment e.g. at ATCC or airline sites
Aircraft Earth Station
smaller due to limited design goal
low power, cheaper
Spectrum Efficiency
maximise frequency reuse
specific protocol to carry short frequent data
efficient mapping of user data to satellite physical link

18. Satellite Data Link System
SDLS is attempting to meet the desirable features
a tool-box of good ideas
can pick any or all of the tools to for a new system
ESA has sponsored a considerable amount of design effort to match technology with perceived requirements
a lot of work by satellite system manufacturers
contribution to the input to a possible open standard for aviation use
Development of a ‘ demonstrator ’ underway

19. Key features of SDLS (1/2)
Multiple Access Scheme
Synchronous CDMA in the fixed to mobile direction
Quasi Synchronous CDMA in the mobile to fixed direction
Aircraft Earth Stations
New CDMA modems being developed
Low cost solutions
Space Segment
MSS geostationary satellites at L-Band have already been deployed worldwide and hence are fundemental building block
Ground Earth Stations
Ku or C-Band depending on satellite feeder links

20. Key features of SDLS (2/2)
Services
Voice service (point to point and “Party Line”) 
Data service including broadcast and polled
Network Architecture
Capability for decentralised satellite access
Satellite Diversity
Asumed to be required to meet availability requirements
Equipment Redundancy
For both airborne and ground is part of the design
Communication Resource Management
Fixed and demand assignment, handling of priority levels

21. Ground Earth Stations Two main types of feeder links C-band
currently used by Inmarsat GESs on global and spot beams. Requires large antennas but the infrastructure is there and will be for the foreseeable future to support maritime services
Ku-band
allows the use of smaller (cheaper) GESs. Could be deployed at or near ATC centres or airline operational control centre
Ku-band is more subject to atmospheric disturbance than C-band - has to be taken into account in design
Only Ku-Band VSATs practically allow highly decentralised access

22. CDMA channel structure
Up to 255 CDMA channels per subband

23. Satellite Protocols Reuse features of AMSS e.g.
Reliable Link- type service
AMSS strategy for priority, reference number…
Data rate determined by type of satellite beam size
Minimum data rate in global beam
Basic channel rate is 6.8kbps - in global beam (determined by vocoder)
Short message data throughput is 1.35kbps
Long message data throughput is 2.4kbps
Spot beams increases rate at least 4 times.
Broadcast capability - ground to air

24. Voice service Vocoder rate of 4.8kbps - may be the same as AMSS
Full duplex circuit mode service for ‘normal’ use
suitable for AOC and some ATS applications
Special feature to emulate ATS RT
‘party-line’ feature - allows rebroadcast of messages to other aircraft
requires dedicated channel per sector
synchronous CDMA - no signal acquisition time

25. Satellite diversity Satellite diversity could be required due to -
shielding of the aircraft antenna by the structure of the aircraft
failure of the satellite system
This requires on the ground -
one antenna for each satellite in view by the GES,
one spare GES antenna to ensure the reliability
Pre-assigned spectrum for each satellites

26. Satellite diversity

27. Aircraft Earth Stations
Simple and cheap
isotropic antenna
low RF power - no forced air cooling requirements
single transmit channel per AES
need 2 AESs per aircraft to achieve redundancy requirements
Direct data inputs for Polling Services e.g. A429
Interfaces to CMU/ATSU and voice distribution system

28. Aircraft Installation

29. Initial Deployment in ECAC

30. Ground architecture

31. Other deployment options
Whilst a solution based on global beams is a practical early solution (maybe preferred in ECAC area), other options are possible
Incremental flexible deployment can be provided through the use of spot beams where required
This could be an attractive first step in some areas of the world e.g. where there is not a well developed terrestrial infrastructure

32. Later deployment in ECAC

33. Ground Architecture

34. SDLS Demonstration Programme
SDLS Programme Phases
Key system performance demonstrator with AESs on ground (on-going with targeted completion third quarter 2002)
2 AESs
2 GESs - Ku band
ATS/AOC application emulation
EMS satellite
Evaluation with airborne avionics and the participation of ATSPs and airlines is in the planning stage

35. Institutional aspects
Standardisation
new satellite systems capability needs to be standardised for worldwide operation
confirm that NGSS SARPS are appropriate - seem so at initial review
Access control to space segment - who, how ?
Use of AMS(R)S spectrum with many service providers
GES operators
detailed technical standards
co-ordination between them e.g. use of codes, hand-overs, etc

36. Business Issues
Technically SDLS looks possible but there is a need to clarify business drivers
Targeted at AMS(R)S therefore has to be paid by ATSPs and airlines only e.g. no APC traffic
However it is not vulnerable to market failure
Benefits must come from cost saving
‘do nothing’ cases must be considered
compare technology solutions
Cost must be minimised

37. Issues for further consideration
Data rate
Lowest rate assumed acceptable - need to confirm (e.g. AOC)
Use of Polling Service
How is it used in practice ? Who controls the service and shares the data ?
Efficient use of satellite physical link
need optimise the mapping of user data onto RF link
ATSC voice service
design of human interface for access
party line acceptance

38. Conclusions (1/3)
Satellite based communication system have advantages for aviation
wide coverage capability
could overcome need for terrestrial infrastructure development in some areas of the world
traditionally thought of as oceanic and remote areas only but with improved performance and lower cost can be considered for higher density airspace
Advanced design concepts seem to show that higher service quality levels than AMSS are achievable with proven technology
can draw on AMSS experience and institutional arrangements
ability to enable new service provision possibilities

39. Conclusions (2/3)
Technical design concepts are well advanced in SDLS but still open to refinement
Finalisation of design in consultation with aviation community
Institutional arrangements
standards development - SARPS, MASPS, MOPS, etc
can draw on NGSS work already undertaken
Business case
costs should be lower due to specific AMS(R)S goal
better define the benefits including ‘do nothing ’ option

40. Conclusions (3/3) Recommendation on next steps in WG-C
Contribute to the production of a global operating concept to augment the ECAC Operational Concept
Contribute to the development of a design definition document
To liaise with AMCP WG-F to ensure the availability of adequate AMS(R)S spectrum
Address in due time the development of a Manual