acp wgf26 wp17

							                                                                                       ACP/WGF 26/WP 17
                      International Civil Aviation Organization

                      WORKING PAPER




                    AERONAUTICAL COMMUNICATIONS PANEL (ACP)

                         26TH MEETING OF THE WORKING GROUP F

                              Montreal, Canada, 21 – 30 March 2012


Agenda Item 4 : Review, update and development of the ICAO Frequency Spectrum Handbook


                        Proposal for a Policy Statement on Spectrum Usage

                                    (Presented by the John Mettrop)




                                             SUMMARY
           This paper proposes that ICAO make a clear statement about what spectrum
           can be used to provide civil safety of life aeronautical services and under what
           conditions.
                                               ACTION
           The meeting is invited to consider the need for a policy statement on spectrum
           that may be used for safety of life aeronautical systems usage and the
           adoption of the proposed draft text for such a statement.



INTRODUCTION

ICAO has traditionally designed and SARPed radiocommunication systems (communication,
navigation and surveillance) to operate in bands either allocated to or identified for what are generally
regarded as “safety of life services” (AM(R)S, AMS(R)S, ARNS, ARNSS) in the Radio Regulations
The ICAO Frequency Spectrum Handbook identifies these services as appropriate for use by
aeronautical systems but also identifies a number of other radiodetermination service designation
which by inference may be used.


DISCUSSION

Recently this practice has been questions in studies such as those on unmanned aircraft where there
have been proposals to use frequency bands allocated to services other that AM(R)S, AMS(R)S,
ARNS, ARNSS for the provision of safety of life applications.
The use of frequency bands allocated to “safety of life services” for safety critical aeronautical
applications brings a number of benefits not just to aviation. Some of these benefits are:-

    1)            Clearly identified frequency bands where aeronautical safety systems are operating
    2)            Knowledge that any assignment operating in those frequency bands has been planned
          in accordance with known planning rules that have been accepted by ICAO as safe.
    3)            Knowledge that any assignment operating in those frequency bands has been co-
          ordinated with all of the requisite authorities and been approved by those authorities and that
          any caveats placed on approval of that assignment have been addressed and resolved.
    4)             That all assignments are registered appropriately whether that be in the master
          international frequency register or the relevant regional or global ICAO database and
          therefore taken into account in co-ordination of other assignments.
    5)             That all of those assignments operate in accordance with the radio regulations and the
          definitions contained therein and they can claim protection from other systems.
    6)            That interference to systems is reported in a transparent manner and addressed in the
          appropriate timescale.
    7)            That article 4.10 of the Radio Regulations is applied to the relevant frequency band
    8)            A safety margin as well as realistic worst case conditions can be applied during
          sharing studies.
    9)            A consistent policy across all systems and frequency bands
    10)           That the frequency bands where provisions such as a safety margin and worst case
          conditions are kept to a minimum and thus do not unduly affect the capacity of other systems.

There are two examples, listed below, where ICAO standardised systems operate in an allocation to a
non-safety:-

                  Feeder links to satellites providing AMS(R)S
                  Satellite navigation

However for each of these systems there are mitigating circumstances, for AMS(R)S it is backed up
by an alternative radio link that in a safety frequency band and for satellite navigation the frequency
bands of operation are also allocated to a safety service. It should be noted that VSAT’s and Primary
Radar are operated in bands not allocated to safety services, however these systems are not
standardised by ICAO and use of such systems is based on local agreements.

The current arrangements serve aviation well in the protection of its systems and whilst it may be
possible to envisage an alternative arrangement, such an arrangement will need to be able to stand
scrutiny for any scenario and be acceptable by aviation for other non-safety services. As such
alternative arrangements have yet to be agreed it is proposed that ICAO make a clear policy statement
as to the types of radiocommunication services that it is prepared to accept as appropriate for the
development of SARPs. A proposed draft for such a statement is contained below:-

“That spectrum to support global aeronautical radiocommunication systems must be appropriately
allocated on a global basis in the ITU Radio Regulations to a relevant safety service (AM(R)S,
AMS(R)S, ARNS or ARNSS)”.

It is noted that additional text will be required to cover the two exceptions listed above

ACTION BY THE MEETING
The ACP WGF is invited to consider the need for such a statement and whether the proposed draft
statement can be used as a basis for such a statement.