Aeronautical Mobile Communications Panel WP/WGF2/9 Working Group F : Second Meeting
Bangkok 5 to 14 May 1999
(Paper presented by Secretariat )
Agenda item5: Revisions to the ICAO R/F policy handbook: revisions to the policy statements in the light of the ICAO position for WRC/2000 (presented by the Secretariat)
1 Introduction
1.1 The Handbook on Radio Frequency Spectrum Requirements for Civil Aviation ICAO Doc.9718-AN/957, Edition 1, as approved by ICAO Council, was published and made available to States and others in mid 1998. The Handbook contains important factual material on the use of the Radio Frequency Spectrum arranged in the frequency bands used in civil aviation. Included against each frequency band is a statement of ICAO Policy for use by States and ICAO observers at meetings on spectrum related subjects, and particularly for meetings and Conferences of the ITU
1.2 A number of actions have taken place since publication, and some of the material now requires adjustment. Practically all of the changes which are proposed in this paper have resulted from meetings of ICAO Panels and States preparations for the ITU WRC2000. This paper addresses the changes which are now necessary to the statements of ICAO Policy, in order to align the Handbook with other ICAO documents, and in particular with the ICAO Position for WRC 2000. Following review by the Working Group, the material will be submitted for policy approval by the Air Navigation Commission and the Council. Following approval, an amendment sheet will be issued.
1.3 Changes to the narrative associated with these policy changes are presented in a companion paper.
2 Detail of Amendments
2.1 Radar Bands at 3GHz
The 3 Radionavigation and/or Radiolocation bands at 3 GHz ( 2.7 - 2.9 GHz ARNS, 2.9 - 3.1 GHz RN, 3.1 - 3.3 GHz RL ) are extensively used by 10 cm radar for airport and en route surveillance . There is also extensive maritime and national defence use. To locate new spectrum for the ITU IMT2000, the new global terrestrial/satellite multiple communications service, attention has been focussed on these bands with a view to sharing, or release of spectrum from the radar services. Sharing does not appear possible with a high probability of intolerable interference to both services, causing possible strobing on radar displays, and high power pulse interference to MSS. receivers.
On the question of a possible reduction in the spectrum available for radar services., the use of primary radar for surveillance, earlier expected to be phased out under the CNS/ATM concept, is taking longer due to the delay in the appearance of more modern surveillance means. Hence, any decision on reduction can only be taken after a comprehensive review of present and future use. An ongoing and more permanent requirement will probably continue at high density traffic airports for the foreseeable future.
The following amendment to the ICAO Policy is proposed::
Handbook Page 7-82
ADD new bullet point
· Ensure that any proposals for sharing, or reductions in these bands, are fully researched, validated and coordinated with other users
2.2 Proposals for GNSS Sharing with MSS in the Band 1559 to 1567 MHz
The studies under Resolution 220 of WRC97 on the feasibility of sharing of MSS with GNSS in this band are now completed. All of the work has concluded that sharing is not feasible due to the required protection to GPS, pseudolites and other GNSS augmentation systems. These conclusions will be presented to the CPM meeting at the end of 1999 for incorporation in the CPM Report to WRC2000.
The following amendment to the ICAO Policy is proposed::
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· Support the conclusions of ITU-R WP8D that sharing between the MSS and the GNSS I the band 1559 to 1567 MHz is not feasible.
· In any future discussions support the protection level of minus [ - - - ] as the maximum tolerable interfering signal level from non-aeronautical sources.
2.3 WRC Item 1.10 :Mobile Satellite Bands 1525-1559 MHz and 1626.5-1660.5 MHz
WRC-97 introduced a generic allocation to the mobile satellite service in these bands in which any frequency could be used by any element of the Mobile Satellite Service (i.e. land, maritime or aeronautical). A footnote was agreed addressing the 10 MHz bands previously allocated to the AMS(R)S, intended to provide for a priority in the coordination of spectrum for this service, and a dynamic priority for aeronautical communications in Categories 1 to 6 of Article S.44. over all other mobile satellite communications, if necessary. To meet aeronautical (and maritime) concerns Resolution 218 was adopted, calling for studies of the future spectrum need for AMS(R)S, and for methods of preemption within a network., and for studies of interoperability. In ITU a network is defined as one space segment and all of the associated ground stations.
Studies in ITU-R WP8D are now being finalied for submission to the CPM for the WRC-2000 which indicate that preemption within a network is practicable. However, it will add cost and complexity to satellite networks to all terminal. Aeronautical concern with the inadequacy of Footnote S5.357A intended to guarantee access to aviation to RF spectrum in the future now necessitates a change in its provisions.
The following amendment to the ICAO Policy is proposed::
Handbook Page 7-82
MOD
· Retain S5.357 S5.375, S5.376, S5.357A, S5.362A
ADD new bullet points
· Amend Footnote S5.357A to provide a positive guarantee that AMS(R)S spectrum requirements can be satisfied to meet a future expanding requirement with full protection for communications in Categories 1 to 6 of Article S44 of the ITU Radio Regulations.
2.4 New Allocations for the Radio Navigation Satellite Service
Under this heading there are the following elements
(i) A requirement for a second civil GPS frequency at the 1176.42 MHz has been stated. The channel width has been provisionally specified at 24 MHz. The selected frequeny is in the band used for DME which is heavily utilized for DME and TACAN and other national systems. The scope for sharing is currently being reviewede by the GNSS panel.
(ii) Proposals for second generation RNSS are beginning to appear using new technology. Typical of these are the European ENSS-1, and the L/MSATNAV both of which have registered frequencies in the existing RNSS band. In these designs aviation use is one of the target users. The band 1559 to 1610 MHz can support further systems provided it can be maintained free from other uses in the years ahead. It should be noted that the MSS service may still originate proposals for sharing if the frequencies in the 1559 to1567 MHz are not fully utilized.
(iii) In the search for free spectrum the RN Sat Service the 5000 to 5030 MHz section of the MLS band has also been examined. Use of this band, allocated to the aeronautical radionavigation service, has not been stated by ICAO. A proposal to use this band for RNSS Earth-to-satellite transmission will have limited effect on the planned MLS usage, provided the unwanted emission of the system can be kept low enough.
Page 7-53
The following amendment to the ICAO Policy is proposed::
MOD · Support a new allocation for RNSS in the band between 1164 - 1188 MHz for the second civil GPS frequncy, subject to the condition that the DME requirements for channel will not be affected.
Page 7-76
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· Support proposals for the utilizsation of the band 1559 to 1610 MHz for next generation satellite navigation systems insofar as they can be successfully integrated in this band
Page 7-89
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· Resist any use of the band at 5000 to 5030 for RNavSat allocations. For this purpose give support for proposals to use the section above 5090 MHz
25 WRC Item 1.14 : Band 15.4 - 15.7 MHz
WRC-95 added an allocation for the FSS to this band for feeder link use for NGSO Mobile Satellites, and requested studies. On the basis of these studies, WRC-97 established a sharing arrangement for the various different aeronautical radionavigation systems which are already using the band and the incoming FSS earth stations. At the same time the footnote prohibiting airborne use in the 15.45 to 15.65 MHz part of the band was removed. WRC-97 called for further studies, primarily with respect to the need to avoid interference to the Radio Astronomy Service in the band below.
The sharing to protect the aeronautical radioonavigation services, which includes ASDE radar and airborne radar altimeter, was found unduly restrictive to the FSS - for example very large dish sizes were necessary. Subsequently, evidence was acquired that the requirement to use this band for the fixed satellite service, which had only been a standby for operations in higher frequency bands, had been abandoned. Also a major company with a predominant interest in using this band ceased to exist. There would appear to be no need for the allocation to the FSS in the Table of Allocations, and the restrictions which it places on use by the ARNS would be removed by its deletion. Any minority use for FSS in particular countries should be accommodated by footnote.
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The following amendment to the ICAO Policy is proposed::
ADD
· Support proposals for the deletion of S5.511A as no longer required for world wide availability. Support the substitution by country footnote for any minority use.
3 Action proposed
3.1 The Working Group is requested to consider the above and to make Recommendations for further action.