ACP WGC6/WP7
AERONAUTICAL COMMUNICATIONS PANEL (ACP)
Working Group C – 6th meeting
Toulouse, France
20 – 24 October 2003
Agenda items 6: Evaluation of potential technologies
Status and review of the emerging satellite communication technologies
Presented by Philippe Renaud
Prepared by Phil Platt
SUMMARY
This working paper provides an overview of satellite communication technologies that
are being used to support communication with aircraft or are under development. The
information in the paper is based on the best available information available to the
author – comments and corrections are welcome.
1.
Background
Some airlines have invested heavily in the current Aeronautical Mobile Satellite Service
(AMSS) and it is being used on a proportion of these aircraft for ATC purposes. However, other
satellite systems are being fitted to aircraft for a range of purposes.
This paper gives a high level overview of the all satellite systems, their status and planned usage,
and gives a subjective appraisal of their potential use to support safety communications. The
information in the paper is based on the best available information available to the author –
comments and corrections are welcome.
2.
Satellite Systems
2.1
Inmarsat Systems
The current ICAO AMSS is compatible with the ‘classical’ Inmarsat systems namely Aero H,
H+, I and L and these contain specific provisions to support safety (AMS(R)S) and non-safety
communications. They operate in the L-Band and are currently the only systems that are
recognised to carry aeronautical safety communications.
Initial deployment was based on the Aero H/H+ high gain antenna systems for voice and data
services. Later the Aero I intermediate gain systems were introduced with a cheaper antenna for
service in spot beam, and also the data only low cost Aero L ( the most notable use is for
helicopter safety in the Norway area of the North Sea).
The deployment of AMSS has never reached the levels originally predicted with around 3000
aircraft equipped today; these are mainly long haul aircraft. Around 1200 of these are FANS1/A
equipped for ATM use in various regions of the world - mainly remote or oceanic – where the
applications and associated benefits are met by the end-to-end performance of the implemented
system. FANS1/A is based on ACARS messaging techniques and consequently the performance
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is largely determined by the efficiency of the end-to-end network of which the satellite link is
only a part.
In 2002 Inmarsat introduced a new aeronautical communication system called Swift64 which
reuses the existing Aero H installation on an aircraft and offers high-speed data service – 64
kbps - for non-safety use. Swift64 shares some of the components of an existing Aero H
installation e.g. the HPA and antenna to provide the new ISDN or data packet data services.
In the future another product BGAN (Broadband Global Area Network) can offer high data rates
(432kb/s) in spot beams. Again this service is believed to be aimed at non-safety uses.
Regional BGAN (RBGAN) is an initial implementation of the BGAN service and uses the
existing Thuraya satellite network which provides a high speed data service covering large parts
of west and eastern Europe, Africa and the Middle East. This service does not appear to be used
by aviation.
2.2
Connexion by Boeing®
Connexion by Boeing provides high-speed, two-way Internet-based connectivity to aircraft in
flight and is designed to support two market segments: commercial aircraft operators and their
passengers as well as executive aircraft, including operators of private and government executive
jets. Connexion was one of the main candidate systems as for a Next Generation Satellite
System (NGSS) under discussion in AMCP WG-A. However it is believed that there has been
no further consideration of Connexion to support safety communications.
WRC 03 agreed to extend the secondary mobile satellite service allocation in the 14-14.5 GHz
band to include the aeronautical mobile satellite service allowing Connexion by Boeing and
other satellite-based services into the global communications market for non-safety
communications.
The Connexion by Boeing system comprises 
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Airborne system: airborne antennas, airborne servers, routers, and associated
wiring. Boeing has developed a proprietary solid-state phased array receive
and transmit antenna.
Ground system: network operations centre, associated satellite uplink and
downlink equipment, and business operation centre.
Space system: leased satellite transponders. Arrangements have been made
with a number of satellite service providers including Intelsat, Eutelsat, etc.
Connexion by Boeing is obtaining relevant authorisations from the national regulatory agencies
in those countries where the system operates including the civil aviation authorities responsible
for aircraft offering the service.
Lufthansa, British Airways, SAS and All-Nippon Airways, have equipped, or are going to equip
with Connexion by Boeing.
2.3
Iridium
The Iridium system was another of the main candidate systems to be considered as an NGSS
under discussion in WG-A.
The original Iridium company went bankrupt and an organisation with less ambitious goals is
now offering a commercial service. Iridium currently provides services to the United States
Department of Defense and launched commercial services worldwide in March 2001.
The Iridium Satellite System is the only provider of truly global voice and data capability with
complete coverage of the Earth (including oceans, airways and Polar regions). The Iridium
constellation comprises 66 low-earth orbiting (LEO) satellites operated by Boeing. Iridium
suggests that its service ‘is ideally suited for industrial applications such as heavy construction,
defense/military, emergency services, maritime, mining, forestry, oil and gas and aviation’.
The FAA is using Iridium to complement the UAT coverage system in Alaska CAPSTONE
ADS-B project. It is believed that avionics manufacturers are developing products to support
ATS applications.
2.4
Globalstar
The Globalstar constellation consists of 48 Low-Earth Orbiting (LEO) satellites providing
coverage of over 80% of the Earth's surface, (excluding the extreme Polar Regions and some
mid-ocean regions). The satellites are placed in eight orbital planes of six satellites each,
inclined at 52 degrees to provide service on Earth from 70 degrees North latitude to 70 degrees
South latitude.
The satellites utilise "bent pipe" architecture and a user’s signal will be received by several
satellites and retransmitted via CDMA to a satellite dish at the appropriate ground Gateway
where the call is then routed locally through the terrestrial telecommunications infrastructure.
This system appears to be targeted mainly at General Aviation however it should be noted that
avionics is available that complies with the RTCA NGSS MOPS. ARNAVSystem Inc has
developed a fully qualified (FAA and FCC) voice and data capable aviation product the RCOM100, which is capable of providing either circuit switched data or packet data at 9.6 kbps
throughput.
3.
Safety versus Non-safety usage
Other than the Inmarsat Aero H, H+, I and L systems, none of the above systems was
specifically designed to carry safety-related communications nor are they currently defined in
ICAO SARPs.
The original Iridium company was committed to put in place the extra provisions in their
network to achieve the required level of service to carry safety communications. Initial technical
provisions were being considered in AMCP WG-A. This work was halted when the company
became bankrupt.
Connexion by Boeing was also being considered as an NGSS by WG-A and some initial
material for a Technical Manual was being developed.
Now several years later, it is understood that none of the proponents of these non-safety systems
is intending to offer the systems for safety communications however the need to support safety
communications may become more attractive given the right economic environment.
So what would it take to make these systems suitable for safety communications ? The following
issues need to be considered 
Appropriate RF band – is the system operating in a designated AMS(R)S
band?
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Priority – do safety communications get priority over non-safety traffic ?
Certification to correct level – are the avionics certified to the appropriate
level, typically Level C software? Is the Ground Earth Station software
developed to the appropriate standards ?
Provisions to offer correct QoS – are the satellite service providers willing to
offer an appropriate guaranteed level of service ? Have they put in place
appropriate network monitoring and control facilities ? Have they carried out
an appropriate safety case analysis ?
Are the appropriate international standards in place ?
If no specific provisions to handle safety communications have been put in place does this mean
that it cannot support safety communications ? It is suggested that the answer may not
automatically be no and has to considered on a case-by-case basis. For example, suitable
mitigation measures may be able to be put in place to overcome any risks or it may be possible
to modify the existing systems to better meet safety requirements.
4.
Conclusions
The Working Group is requested to the note the information in this paper.
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