Thales Avionics

Comments and Tradeoffs for NexSAT

Prepared by Alan Schuster Bruce - Presented by Andy Lovett

Eurocontrol NexSAT Steering Group

Brussels, 20 May 2003

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Thales Avionics Satcom Activities

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

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Thales Assessment for Eurocontrol of NexSAT

What are the key issues?

What are the tradeoffs?

Recommendations?

Are there any show stoppers?

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Services, Coverage Area and Channel Types

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

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Link Budgets

Comprehensive link budgets must be produced The heart of any satellite system design

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Channel type

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 1/2 400

Total 5600

RF Channel SR for QPSK

2800

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HPA Issues

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

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Key recommendations

1. No showstoppers but:2. Define services and their coverage (spot/global beams) - clarify

need for simultaneous voice and data3. Provide 2 or 3 services each with an associated channel type

(global/spot/existing Inmarsat a/c)4. Produce comprehensive link budgets and define channel

types 5. Lower rate vocoders (2400bps) should be investigated6. HPA should be cooled for most aircraft7. Use a low gain antenna to keep cost low and fit on small a/c

Thales Avionics

Comments and questions to:Alan.Schuster-Bruce@uk.thalesgroup.com

+44 20 971 5407

Thank you for your attention

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