1. Alan Schuster Bruce, Thales Avionics, 31 May 2005
NexSAT Steering Group - 31 May 2005 AeroBGAN Feasibility Study WP3: Airborne Architectures for SwiftBroadband Services
Alan Schuster Bruce, Thales Avionics, 31 May 2005

2. Contents Todays Satcom Architectures Key Questions on Architecture
NexSat Steering Group, AeroBGAN Study, WP3 - Airborne Architectures,
Alan Schuster Bruce- 31 May 2005
Todays Satcom Architectures
Key Questions on Architecture
Key Performance Metric
Packaging
Locations
Interfaces
Conclusions

3. Today’s Arinc 741 Satcom Architecture (Plus changes introduced by Arinc 781)
NexSat Steering Group, AeroBGAN Study, WP3 - Airborne Architectures,
Alan Schuster Bruce- 31 May 2005

4. Airborne Architecture Questions
NexSat Steering Group, AeroBGAN Study, WP3 - Airborne Architectures,
Alan Schuster Bruce- 31 May 2005
What performance is needed?
What are satcom functions?
How could they be packaged?
Where would they be placed on aircraft?
What are satcom cockpit user interfaces?
Same functional interfaces will be needed

5. Performance Key metrics are G/T and EIRP. Inmarsat SDM figures are:
NexSat Steering Group, AeroBGAN Study, WP3 - Airborne Architectures,
Alan Schuster Bruce- 31 May 2005
Key metrics are G/T and EIRP. Inmarsat SDM figures are:
An LGA will be required on smaller aircraft and hence this is the dimensioning service.
Will the LGA system deliver the required service?
Will depend on required data rate and QoS, and these will depend on end-user applications. Being considered in WP1
LGA G/T implies 0dBic antenna and state of the art DLNA, and <0.3dB cable loss.

6. HPA Power vs EIRP
Inmarsat SDM sets EIRP for a LGA Terminal as provisionally 11dBW
Figure shows required HPA power to meet this
Between 16 and 22W of RF power at HPA output will be required
NexSat Steering Group, AeroBGAN Study, WP3 - Airborne Architectures,
Alan Schuster Bruce- 31 May 2005

7. Arinc 781 Satcom Architectures (with and without external HPA)
NexSat Steering Group, AeroBGAN Study, WP3 - Airborne Architectures,
Alan Schuster Bruce- 31 May 2005

8. Architecture Packaging Question
NexSat Steering Group, AeroBGAN Study, WP3 - Airborne Architectures,
Alan Schuster Bruce- 31 May 2005
Basic functions are:
SDU function - Modem and interface to aircraft
HPA function - power amplification
DLNA function - diplexer to combine Tx and Rx, plus receiver low noise amplifier
Antenna function
How can they be packaged?

9. Possible Satcom Packaging
NexSat Steering Group, AeroBGAN Study, WP3 - Airborne Architectures,
Alan Schuster Bruce- 31 May 2005
Same colour indicates functions combined into one LRU

10. Arinc 741 and 781
NexSat Steering Group, AeroBGAN Study, WP3 - Airborne Architectures,
Alan Schuster Bruce- 31 May 2005
Arinc 781
Specification activity considers future ATS over SwiftBroadband, although issues not currently being worked.
Certification level may rise to Level C
Reasonable to assume that safety services will be supported by Arinc 781 equipments (but not from all manufacturers).
Arinc 741 Equipment could be upgraded to support safety services - time will tell if this happens not least since basic designs are ‘old’, and will be ‘very old’ when the new system is rolled out.

11. Satcom Architecture Locations-1
NexSat Steering Group, AeroBGAN Study, WP3 - Airborne Architectures,
Alan Schuster Bruce- 31 May 2005

12. Satcom Architecture Locations-2
NexSat Steering Group, AeroBGAN Study, WP3 - Airborne Architectures,
Alan Schuster Bruce- 31 May 2005

13. Satcom Architecture Locations-3
NexSat Steering Group, AeroBGAN Study, WP3 - Airborne Architectures,
Alan Schuster Bruce- 31 May 2005

14. Satcom Architecture Locations-4
NexSat Steering Group, AeroBGAN Study, WP3 - Airborne Architectures,
Alan Schuster Bruce- 31 May 2005

15. Interfaces To Cockpit-Voice
NexSat Steering Group, AeroBGAN Study, WP3 - Airborne Architectures,
Alan Schuster Bruce- 31 May 2005
Expected that both current interfaces and new digital interfaces (eg AFDX) will be required in future.
New digital interfaces may be on single or multiple physical connections

16. Voice over SwiftBroadband PS
NexSat Steering Group, AeroBGAN Study, WP3 - Airborne Architectures,
Alan Schuster Bruce- 31 May 2005
SwiftBroadband can support voice by circuit or packet services. If the latter - where will the function (e.g. VOIP, multicast) reside to convert to circuit user services be provided:
In SDU?
In another unit?
Industry will need to consider this issue

17. Interfaces To Cockpit-Data
NexSat Steering Group, AeroBGAN Study, WP3 - Airborne Architectures,
Alan Schuster Bruce- 31 May 2005
Current interface is
Data2/Williamsburg/Arinc 429 (FANS 1/A)
Data3/Williamsburg/Arinc 429 (ATN compatible)
Key question is how this will migrate to the IP environment supported by SwiftBroadband
Tunnel existing Data2/3 over IP
Migrate to pure IP environment
ICAO ACP is considering accommodating IP
Where will this function reside
In SDU?
In another unit?
Industry will need to consider this

18. Interfaces To Cockpit-Control and Maintenance
NexSat Steering Group, AeroBGAN Study, WP3 - Airborne Architectures,
Alan Schuster Bruce- 31 May 2005
Todays Interfaces
Control of satcom e.g. logging on, GES preferences etc although these are typically automatic (uses MCDU)
Display of BITE (uses CFDS)
Upload of software/configuration data (uses ADL/PDL)
The above interfaces are expected to also be required for any future service.
These interfaces are not fundamentally dependent on whether the satcom uses classic or SwiftBroadband.
The current interfaces could be duplicated or a new generation of interfaces (e.g. AFDX) could be developed – the latter will depend on general trends in avionics.
It is expected that both existing Arinc 429 type interfaces and newer interfaces will be required for different aircraft

19. Conclusions LGA is expected to meet some ATS requirements
NexSat Steering Group, AeroBGAN Study, WP3 - Airborne Architectures,
Alan Schuster Bruce- 31 May 2005
LGA is expected to meet some ATS requirements
Various packaging options are possible
Different options expected for different market segments
Arinc 781 equipment should support safety services
Arinc 741 could be upgraded to support new services but equipment design is ageing.
Installation locations reviewed
Voice interfaces will have similar functions but may migrate to digital
How will IP be handled? VOIP/multicast in SDU or external unit