1. ICAO Seminar on the Implementation of Datalink and SATCOM Communications Bangkok, November VHF ACARS to ATN Akhil Sharma

2. Outline VDL Mode 2 Background ACARS over VDL AVLC – An Interim Step
SITA VGS
VDL Mode 2 – Drivers for Deployment
SITA/AENA Partnership Agreement
VDL Mode 2 Coverage
ATN Service Provision

3. VDL Mode 2 Background
Aircraft implementation of ACARS started in 1978 using VHF voice radios to limit the avionics cost.
Attempts were made in the 1980’s to implement a higher capacity VHF digital system but the business case could not be made.
An IATA recommendation, supported by SITA, to the ICAO conference in in 1990 led ICAO to launch the standardisation of VHF digital link.
ICAO specified that the VHF digital link would enable the exchange of both air traffic and aeronautical operation control messages.
ICAO in 1996 completed standards of for VDL Mode 2
VDL Mode 2 uses digital radios to provide aircraft with a data link to ground stations at a rate of 31.5 kbit/sec using a radio channel the same width as the legacy VHF analogue ACARS system uses to provide its capacity of 2.4 kbit/sec.

4. VDL Mode 2
One VDL Mode 2 channel provides at least 10 times more capacity increase over one ACARS channel
VDL Mode 2 is operational today using single 25 kHz channel shared between service providers
Selected by Eurocontrol and the FAA as the initial subnetwork technology to enable CPDLC
Consistent with IATA position

5. VDL Mode 2/AOA
AEEC defined in 1999 an interim architecture that serves as a step towards ATN referred to as “AOA”, “ACARS over VDL AVLC”
AOA allows existing ACARS applications to benefit from the higher bandwidth offered by VDL M2
Main benefit, in addition to capacity increase, is that no change required to the interface to airline or ATS ground systems
For aircraft, transition from AOA to ATN/VDL Mode 2 will require a software upgrade to the avionics
All ACARS avionics vendors now offer VDL AOA avionics
Several major AIRCOM customers planning AOA retrofits across the majority of their fleets
SITA evaluation of VDL AOA service with KLM (B737’s) has demonstrated that the service is working

6. VDL/AOA/ATN

7. SITA VGS Architecture SITA Ground Network ATN Router ACARS Processor
Wide band
Antenna
interface (8) - X1
Antenna Relay switches
Narrow band
Antenna
interface (8) - X2
interface (1) - X10
VHF Data Radios: Each VDR can be programmed to handle
VHF analog ACARS or VHF Digital Link Mode 2
GPS
source
Uninterruptible Power Supply
Power Supply
Dual Power Supply
VHF Ground Computer (VGC)
Laptop computer
for maintenance
VDL Subnetwork
Connections
SITA Ground Network
ATN Router
ACARS and VDL AOA Traffic
VGS Management
Interface
ACARS Processor
VDL Management
Entity Processor

8. VDL Mode 2 Deployment Drivers
SITA deployment of VDL Mode 2 coverage is being driven by two main factors:
Airline customer requirements for increased ACARS capacity in areas where the VHF analogue ACARS frequencies most heavily used and congestion is forecast
Air traffic service providers requiring their Controller Pilot Data Link Communications (CPDLC) to use ATN over VDL
Air traffic service providers have the choice to contract service provision or deploy their own VDL networks

9. SITA/AENA VDL Partnership
SITA signed an agreement with the Spanish Air Traffic Service provider, AENA, that will result in:
VDL 2 coverage over entire Spanish terrestrial airspace through 21 AENA owned SITA VGS’ by end 1Q 2004
AENA responsibility for housing, maintenance and management of the service
Seamless AOC service for SITA VHF AIRCOM customers
Platform for the introduction of CPDLC services over the ATN, planned for 2006
Initial concrete example of the CNS industry/public joint ventures foreseen by the European Commission’s Single European Sky initiative
Provides a pragmatic basis for European regional Air Traffic Service provider entity owned VDL network service

10. Non AENA ATS Host Computer
The Architecture
AENA VGS Network Service Boundary
AOC
VHF stations (VGS)
ATN CPDLC
AIRLINE Host Computer
Non AENA ATS Host Computer
AENA
Pre-FANS
ATIS/DCL
AENA G/G Network (REDAN)
SITA Network Service
SITA ACARS
Processor
MADRID
BARCELONA
AENA
FANS 1/A (CPDLC/ ADS)
Network Gateway R R

11. Non AENA ATS Host Computer
The Architecture
AENA VGS Network Service Boundary
FANS
VHF stations (VGS)
ATN CPDLC
AIRLINE Host Computer
Non AENA ATS Host Computer
AENA
Pre-FANS
ATIS/DCL
AENA G/G Network (REDAN)
SITA Network Service
SITA ACARS
Processor
MADRID
BARCELONA
AENA
FANS 1/A (CPDLC/ ADS)
Network Gateway R R

12. Non AENA ATS Host Computer
The Architecture
AENA VGS Network Service Boundary
Pre-FANS
VHF stations (VGS)
ATN CPDLC
AIRLINE Host Computer
Non AENA ATS Host Computer
AENA
Pre-FANS
ATIS/DCL
AENA G/G Network (REDAN)
SITA Network Service
SITA ACARS
Processor
MADRID
BARCELONA
AENA
FANS 1/A (CPDLC/ ADS)
Network Gateway R R

13. Non AENA ATS Host Computer
The Architecture
AENA VGS Network Service Boundary
CPDLC/ATN
VHF stations (VGS)
ATN CPDLC
AIRLINE Host Computer
Non AENA ATS Host Computer
AENA
Pre-FANS
ATIS/DCL
AENA G/G Network (REDAN)
SITA Network Service
SITA ACARS
Processor
MADRID
BARCELONA
AENA
FANS 1/A (CPDLC/ ADS)
Network Gateway R R

14. Non AENA ATS Host Computer
The Architecture
AENA VGS Network Service Boundary
AOC/ATN
VHF stations (VGS)
ATN CPDLC
AIRLINE Host Computer
Non AENA ATS Host Computer
AENA
Pre-FANS
ATIS/DCL
AENA G/G Network (REDAN)
SITA Network Service
SITA ACARS
Processor
MADRID
BARCELONA
AENA
FANS 1/A (CPDLC/ ADS)
Network Gateway R R

15. AIRCOM VDL 2 Coverage

16. VDL in Japan and Brasil
With effect from 1st September 2003, AVICOM introduced VDL/AOA service at New Tokyo and Kansai International Airports
An additional 8 VDL/AOA sites across Japan scheduled for deployment by end 2004
DECEA (Brasil) plans to deploy VDL/AOA capability at Sao Paulo and Rio de Janeiro Airports by mid 2004
The SITA Internetworking Agreements with AVICOM and DECEA enables VHF AIRCOM customers to benefit from the availability of these services

17. Transition towards ICAO ATN
ICAO ATN and associated “subnetwork” standards are finally complete
VDL Modes 2, 3 and 4
Mode S Datalink
AMSS
Main ATN objective is to integrate various air/ground and ground/ground “subnetwork” technolgies into a seamless transparent “end-to-end” service
ICAO ATN Standards include definition of ADS, CPDLC and FIS applications

18. The ATN Concept

19. Link2000+ Programme
Co-ordinating the implementation of CPDLC services over ATN/VDL2 in Europe
Services are compatible with FAA CPDLC Build 1
Maastricht UACC will introduce the service in Dec. 2003
Maastricht FANS 1/A Service re-launched June 03
Two major airlines (SAS and LH) have committed to support the Link2000+ programme for ATN
Eurocontrol is funding upgrade from AOA to CPDLC/ATN/VDL2 for 100 “pioneer aircraft”
Eurocontrol now considering providing funding to States of upto $1M per ACC (max. 5)
ATS providers to pay for ATS data link messages

21. Link2000+ Airline and ATSP Statements
Airlines and ATS providers have stated that:
“Neither aircraft operators nor air traffic service providers shall be constrained in their choice of service provider or routing of ATS traffic exchange”.
“All service providers shall interconnect for the exchange of ATS traffic to provide a seamless connection between the airborne and ground domain”.
The LINK Programme is therefore acting to satisfy these requirements so that ARINC and SITA compete to offer both AOC and CPDLC services to their customers.

22. Initial ATN Architecture
Airline B C
VDL Mode 2
Air Traffic Service Provider
FDPS
ATN
ATN
G/G
A/G
Router
Router A
ACSP Network
ATN
ATN
G/G
G/G
Router
Router
Communications Service Provider

23. SITA ATN Service
SITA plans to launch ATN Service in support of the Link2000+ Pioneer Project by mid 2004
Lufthansa have committed 20 Airbus type aircraft with H/well CMU to be flying in mid 2004 and plan to use the SITA ATN Service
Existing VDL AIRCOM provides coverage over majority of Western Europe airspace
Deployment of ATN service requires integration of ground/ground and air/ground ATN Routers

24. Communications Flows ATN AOA ACARS VDL2 Link AVLC Link VGS RGS
ATN User Traffic
Data Communication Network
ATN Router
ACARS User Traffic
ACARS DSP
Airline ACARS
ATN System
Host

25. Conclusions VDL Mode 2 AIRCOM is operational today
Major airlines planning retrofitting their fleets to VDL/AOA
VDL Mode 2 coverage is driven by AOC and ATS requirements
VDL Mode 2 adopted by Link2000+ and the FAA CPDLC Programme as the initial subnetwork for CPDLC
SITA is open to develop further VDL Mode 2 partnership arrangements with ATS Providers
SITA’s ATN Service planned to be launched mid-2004 for Link2000+

26. Thank you for your attention
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