Page 24 - ITU-T Focus Group on Aviation Applications of Cloud Computing for Flight Data Monitoring - Avionics and Aviation Communications Systems

ITU-T Focus Group on Aviation Applications of Cloud Computing for Flight Data Monitoring
Avionics and Aviation Communications Systems

provides much larger data volumes to aircraft servers and some QAR units that also function as IP data routers
transmitting flight data post flight. These routers if they are connected with and/or integrated with ACMS are
well placed to provide flight data for inflight streaming. ACMS can support triggering and sending anything
from small amounts of data up to full black box data or more and because it is classified as user modifiable
software (UMS), ACMS can be easily changed and deployed on in-service aircraft without need for costly
aircraft re-certification.

All the other on-board information systems listed can send data via ACARS but they cannot support flight data
streaming. They are not easily connected to satellite communication (SatCom) data links and it is not easy to
change triggering or data content sent on all these systems. ACARS AOC has a UMS reprogrammable capability
but it has very limited access to aircraft flight data parameters compared to ACMS.

10.2 On-board aircraft surveillance and tracking infrastructure

10.2.1 Introduction
Aircraft surveillance is considered an air traffic control function. Primary radar was and is used to track
aircraft and it does not require any avionics equipment on the aircraft. Secondary surveillance radar (SSR)
was introduced to expand surveillance to provide additional information related to the aircraft. SSR technology
requires ATC transponders (transmitter/responders) avionics on board the aircraft. Initially Mode A and Mode
C was used for commercial transport, but today aircraft utilize Mode S which is an enhanced SSR mode with
selective interrogation capabilities. ATC or Mode S transponders ignore interrogations not addressed with
their unique identity code, reducing channel congestion. SSR is now being phased out in favour of automatic
dependent surveillance-broadcast (ADS-B) but avionic-wise is an extension of ATC Mode S transponders.

For surveillance needs over oceanic and remote regions which are beyond the reach of terrestrial SSR, very
high frequency (VHF) and ADS-B technologies, there are two main approaches. The first approach is ADS-C.
This is the position report (and other avionics data) which is obtained by the ATC flight data processing (FDP)
system setting up a 'contract' for information from its peer aircraft avionics ADS-C function (this can be in the
FMS on a Boeing aircraft or the air traffic service unit (ATSU) on an Airbus aircraft). This utilizes the ACARS data
link system for communication. ADS-C is the only solution available to ATC today. The second approach, which
will be available in the near future, is space-based ADS-B which is enabled by new ADS-B payloads deployed on
satellite constellations 'listening' to ADS-B 'broadcast' positional data and then relay to the ground. The same
Mode S transponders that are used in terrestrial ADS-B are planned to be used to support space-based ADS-B.

10.2.2 ADS-B

ADS-B is a well-established cooperative surveillance technology and data broadcast standard which has been
used for surveillance for more than ten years primarily overland masses. Space-based ADS-B will enable
global surveillance, including oceanic flight operations, when it becomes operational in 2018. Appendix 2
summarizes the existing or planned ADS-B equipage mandates which will enable maximum operational benefit
to be obtained.
The projected performance of space-based ADS-B is consistent with that of terrestrial ADS-B and fully supports
the flight tracking recommendations made by the IATA Aircraft Tracking Task Force (ATTF) in December 2014
and ICAO's GADSS.

10.2.3 Future air navigation systems (FANS)

The FANS messages are sent over the ACARS data links and networks. FANS applications include:

• ADS-C: Automatic dependent surveillance-contract (ADS-C) is an existing technology with regulatory
approval globally and already provides a two-way communication function between ATC ground systems
and aircraft which can be transmitted automatically without pilot action. This is important as it maximizes

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