Update of ICAO Position for WRC-15 to Support a Future Agenda Item for ADS-B Via Satellite

FSMP WG-F/32 WP19
/
International Civil Aviation Organization
WORKING PAPER / FSMP (ACP)-WG-F/32 WP19
2015-02-16

32ndMeetingof Working Group F

of the Frequency Spectrum Management Panel (FSMP)

(formerly of the Aeronautical Communications Panel)

(FSMP WG-F/32)

(Cairo, Egypt February18-24, 2015)

Agenda Item 7 / Development of potential updates to ICAO WRC-15 Position

Update of ICAO Position for WRC-15 to support a future agenda item for ADS-B via satellite to support air traffic services

(Presented by John Mettrop)

SUMMARY
This working paper discusses the potential benefits that could be accrued from the provision of an ADS-B service via satellite including cost savings due to improved flight profiles and track and trace in a search scenario.
ACTION
WG-F is invited to:-

Support the case for the inclusion of an agenda item at the next WRC to address ADS-B via satellite to support air traffic services
Adopt the proposed brief contained in the annex to this document as part of the ICAO Position to WRC-15

1.INTRODUCTION

1.1Since the development of the FANS 1A concept in 1988 the aviation industry has seen increasing implementation of satellite terminal equipment that is FANS 1A compliant on aircraft. That implementation is either through SARPs compliant Inmarsat or Iridium systems or, more recently, through a non ICAO standardised Globalstar system. All of these systems support both ADS-C and CPDLC with an airline choosing their preferred service provider based on aircraft routing, satellite coverage and cost.

1.2Aireon is in the process of launching an ADS-B payload on the next generation of Iridium satellite that will be capable of receiving and relaying to an appropriate ground station Mode S extended squitter (ES) information. Their intention is to offer a commercial service to air traffic service providers such as Nav Canada and NATS airlines in oceanic and remote regions that it is anticipated will enable improved traffic flow in those areas and to the airlines for track their aircraft. Additionally it is intended that the data will be made available to search and rescue agencies as a public service.

1.3Assuming no delays in the launch of the Iridium satellites then the complete constellation of .ADS-B receivers will be available by 2018.

2.discussion

2.1Currently time based procedural separation is used in oceanic and remote areas, where that separation standard is established based on the communication, navigation and surveillance capability of aircraft and the air traffic management system in that area. Generally this is defined by the update rate of the surveillance data that is derived from the position reports of the aircraft.

2.2For the Atlanticthe current standard, based on position reports every 30 minutes, equates to a 10 minute in-trail separation although for FANS equipped aircraft that is capable of supporting a 15 minute reporting interval trials of 5 minute in-trail separation are currently being undertaken.

2.3Since ADS-B is based on the reception of Mode S ES which broadcasts an unsolicited update every second, the update rate will be significantly higher than that currently available. Even allowing for the latency through the satellite system this should allow for further reductions in the separation standards in oceanic and remote areas.

2.4Additionally as all aircraft flying in oceanic and remote areas are already equipped with Mode S extended squitter and ADS-B via satellite requires no further equipment on-board an aircraft those advantages can be offered to all aircraft rather than those equipped. This simplifies the situation for air traffic controllers.

2.5Events such as the loss of Air France flight AF447 have highlighted the need for improved global flight tracking that can aid initially search and rescue teamsand subsequently recovery teams locate a missing aircraft. At the recent high level safety conference hosted by ICAO in Montreal recommended a number of actions which included the need for operators to determine the position of an aircraft at any time in any location. (note: what the requirements for non-commercial airliners will be, if any, has yet to be determined). ADS-B via satellite offers another alternative means by which operators could achieve this requirement.

2.6The introduction of ADS-B via satellite would therefore provide a significant benefit to aviation. However in order to achieve these improvements a change in the radio regulations is required in order to ensure that the service is in line with those regulations and hence that a safety of life service is protected from interference. That change is the need to introduce an aeronautical mobile satellite (route) service allocation in the frequency band 1088.7–1091.3 MHz.

2.7The agenda for WRC-15 has already been determined and that does not include an agenda item under which ADS-B via satellite can be discussed. However at the recent ITU plenipotentiary conference adopted Resolution 185 which instructed:-

“WRC‐15, pursuant to No. 119 of the ITU Convention, to include in its agenda, as a matter of urgency, the consideration of global flight tracking, including, if appropriate, and consistent with ITU practices, various aspects of the matter, taking into account ITU‐R studies”

2.8Therefore the issue of global flight tracking will be discussed even if it is not under a formal agenda item at the conference. However whilst the introduction of ADS-B via satellite would provide an additional source of information that does not necessarily require a safety service allocation and could even on an interim basis be operated under 4.4. Certainly routine reporting of an aircraft’s position on which no action is taken in my view does not necessarily require protectionalthough should be provided in the long term and when such reports are used to locate a missing aircraft we are then considering an emergency situation where any means available can be used.

2.9Work on-going in the Working Party 5B on a report on ADS-B via satellite still needs to be complete and I have included a list of some of the issues that still need to be addressed in those discussions in Annex 1 to this document. Additionally before an air traffic control service based on the ADS-B via satellite information could be provided there are a number of steps that need to be considered and if appropriate taken in both ICAO and with the national aviation regulatory authorities before benefits can be demonstrated. I include a list of those that I have been made aware of in Annex 2 to this document.

2.10Working Group F has discussed at length the need for aviation to re-establish its credibility and integrity in the ITU. Pressing for an allocation to the aeronautical mobile satellite (R) service, on the basis of:-

Plenipotentiary Resolution 185 which does not call for an allocation to be considered,
Global fight tracking that does not necessarily require in the short term an allocation,
Studies that have not yet been completed and,
No evidence demonstrating that the system will be implemented and delivering benefits in terms of separation standards over and above those already available or being trialed by the next WRC

will not help aviation’s credibility. I would therefore hope that the meeting can agree

2.11Therefore it is proposed that an agenda item should be sought for the next WRC. This would not preclude the benefits that ADS-B via satellite can offer for global flight tracking, Aireon offering the data derived on a commercial basis to airlines or proving trials for an air traffic controlservice.

3.0ACTION BY THE MEETING

Support the case for the inclusion of an agenda item at the next WRC to address ADS-B via satellite for air traffic control purposes.
Adopt the proposed brief contained in Annex 3to this document as part of the ICAO Position to WRC-15

Annex 1

Issues to be Addressed in the ITU Studies

1)The current studies provide little or no information on the technical characteristics of the proposed ADS-B satellite receiver. In principle sufficient information should be provided in order to allow studies to be undertaken by those who wish. It is therefore suggested that the following information needs to be made available as a minimum:-

Either the sensitivity of the satellite receiver or the realistic receivers noise temperature
The frequency response of the receiver and the antenna.
What is the receive antenna pattern including the roll-off and how does it roll-off with angular offset
The maximum number of signals, with justification, that can be handled in an idea situation and in the presence of various fruit levels

2)Currently the link budget is based on free space path loss with no variation to account for variations in the propagation characteristics of the radio path. ITU Study Group 3 recommend for aeronautical telecommunications links from earth to space the use of Recommendation P.618 with input parameters defined in Recommendation P.682. The link budget therefore should be recalculated based on P.618 for an agreed availability requirement.

3)Mode S and TCAS top antenna can be directional with the radiation pattern being optimised for an angle of between 5 and 30 degrees above the ground plane. What antenna pattern was assumed in the link budget provided to the ITU and does this need revising taking into account the actual pattern of the aircraft antenna.

4)Taking all of this into account can the current design of ADS-B satellite receiver still provide global coverage and if not where are the gaps in coverage and does this leave any holes when ground based surveillance is taken into account.

5)How would the link budget look if you were to take into account aircraft other than commercial transport aircraft?

Annex 2

Issues to be Addressed related to aviation regulation

Any service will have to provide evidence through the safety management system process that it can meet the operational requirement. Evidence will have to provided that demonstrates that ADS-B via satellite will meet at least the following criteria:-

1)That relevant ICAO SARPs/handbook material, where necessary, has been produced

2)That the availability, continuity and reliability appropriate for the intended level of service can be met, where necessary through trials work

ANNEX 3

AGENDA ITEM 10 – FUTURE AGENDA ITEMS

AUTOMATIC DEPENDENT SURVEILLANCE -BROADCAST

The standard terrestrial secondary surveillance radar (SSR) operates in the frequency band 1030–1090MHz, the ground station interrogations are centred on 1 030 MHz, the aircraft replies are centred on 1090 MHz. Aircraft automatic dependent surveillance – broadcast (ADS-B) transmissions are centred on 1090 MHz only, the airborne system operates autonomously without any requirement for ground station interrogations. The ADS-B air to ground and air to air systems operate under a global allocation to the aeronautical radionavigation service as modified by footnote 5.328 but is also covered by an allocation to the aeronautical mobile (route) service. They are compliant with ICAO Standards and are compatible with other systems operating in the frequency band and have been in use for many years.

Terrestrial ADS-B has its limitations especially when used as part of a air traffic management system and whilst the provision of ADS-C via satellite does address some of those issues a satellite ADS-B system is desirable. This would, for the first time in many cases, allow air traffic service providers to have a real time accurate and comprehensive picture of airspace in certain remote areas where it has either been impractical or not cost effective before (e.g. oceanic areas out of sight of land). However there is an issue with the radio regulatory provisions surrounding the use of ADS-B via satellite.

Currently the Radio Regulations only contain provisions that address terrestrial service and hence terrestrial systems. In order to introduce a satellite ADS-B service an allocation would be required to the aeronautical mobile satellite (route) service (Earth to space) in the frequency band 1088.7–1091.3 MHz. An agenda item for the next world radiocommunication conference is sought to address this issue and through the associated studies ensure compatibility with the systems already operating in the frequency band.

The provision of a satellite ADS-B system would also have the advantage of improving aircraft track and trace facilities for incidents where the Mode S transponder had not been switched off. For instance it would be reasonable to assume that in 2009 the availability of such a system would have reduced the time taken to locate the Air France flight AF447 that unfortunately crashed in the Atlantic.

Given that track and trace is not regarded as a safety service and hence does not necessarily need to operate under an allocation to a safety service the early provision of a satellite constellation with the capability to receive the Mode S signal would be useful.

ICAO Position:

Support the inclusion of an item on the agenda of a future World Radiocommunication Conference to address the need for an AMS(R)S allocation in the Earth-to-space direction in the frequency band 1 088.7 – 1 091.3 MHz for the satellite reception of existing aircraft ADS-B signals operating in accordance with recognised international aeronautical standards.

Support recognition in the Resolution associated with the agenda item called for above recognition of the value to the early provision of the satellite constellation for track and trace