1. Comments and Tradeoffs for NexSAT
Prepared by Alan Schuster Bruce - Presented by Andy Lovett
Eurocontrol NexSAT Steering Group
Brussels, 20 May 2003
Thales Avionics

2. Thales Avionics Satcom Activities
20 May 2003
Teamed With Honeywell In 1990 to:
Develop Arinc 741/Inmarsat/AMSS terminals
For airlines, business jets and military
Over 2500 systems produced.
Manufactured over 500 antennas for business jets
The leading aero satcom terminal provider in Europe
Thales Avionics

3. Thales Assessment for Eurocontrol of NexSAT
20 May 2003
What are the key issues?
What are the tradeoffs?
Recommendations?
Are there any show stoppers?
Thales Avionics

4. Services, Coverage Area and Channel Types
20 May 2003
Services
Thales believe these should be: simultaneous 1 voice & 1 data but needs confirming based on operational requirements
Investigate 2400 bps voice codecs
Determine data rate/confirm 1000 bps is acceptable
Coverage area
Spot beam services should be included to allow simpler terminal - especially for smaller aircraft
RF Channel types - Thales recommend
Those available on existing Inmarsat equipped aircraft
A type based on global beam
A type based on spot beams
Thales Avionics

5. Link Budgets Comprehensive link budgets must be produced
20 May 2003
Comprehensive link budgets must be produced
The heart of any satellite system design
Thales Avionics

6. Channel type
20 May 2003
Need to be optimised since link budget is always ‘under pressure’. Thales suggest:
Use turbocoding to improve link budget
User rate
Coding
Total
Voice
2400
3/4
3200
Data
1000
1/2
2000
Control (est)
200
400
5600
RF Channel SR for QPSK
2800
Thales Avionics

7. HPA Issues
20 May 2003
HPA efficiency (inclusive of PSU and controller) will rise from 30% to 40%
Aviation industry does not like uncooled boxes due to installation and reliability issues
100W electrical power is limit of uncooled technology which provides 40W RF power and 60W heat dissipation from
But would not be popular and a hence a barrier to uptake.
Only suitable on certain aircraft installations
Thales Avionics

8. Key recommendations No showstoppers but:
20 May 2003
No showstoppers but:
Define services and their coverage (spot/global beams) - clarify need for simultaneous voice and data
Provide 2 or 3 services each with an associated channel type (global/spot/existing Inmarsat a/c)
Produce comprehensive link budgets and define channel types
Lower rate vocoders (2400bps) should be investigated
HPA should be cooled for most aircraft
Use a low gain antenna to keep cost low and fit on small a/c
Thales Avionics

9. Thank you for your attention Question / Answer
Comments and questions to:
Thank you for your attention
Question / Answer
Thales Avionics