Working Group B
Working Group B held two meetings in 2004, WG-B/16 in Tokyo, Japan in January/February, and B/17 in October in Montreal, Canada. WG-B/16 noted the results of the 11th Air Navigation Conference and, in particular, the increased involvement of ICAO in various interference issues, including on-board integration of new (and possibly existing) systems. This would require a greater involvement of ICAO, and in particular WG-B, since on-board integration issues may require frequency assignment planning considerations. WG-B/17 was partly combined with WG-M/9 and addressed issues relevant to the on-board integration of VDL, an issue that is being addressed by both WG-B and WG-M. WG-B/17 completed the frequency assignment planning material, including relevant guidance material, for VHF digital link (VDL) Modes 2. Further consideration was given to frequency planning material and the on-board integration of VDL Mode 3 and Mode 4. In summary, VDL Mode 3 could operate on the fourth adjacent 25 kHz channel from a DSB-AM assignment and on the second adjacent 25 kHz channel from a VDL Mode 3 assignment. Test planning for VDL Mode 4, including the need for an assignment in the 112 - 117.975 MHz band is on-going. WG-B/17 collected material for the development of ICAO guidance material on radio frequency interference for publication by ICAO to assist Contracting States to control radio frequency interference to aeronautical CNS systems operating within their airspace.
Working Group C
Working Group C held two meetings, WG-C/7 in April in Montreal, Canada, and WG-C/8 in September in Munich, Germany. Various meetings of the UAT subgroup were held during 2004 to progress the work on UAT SARPs and guidance material. Work on the use of new technologies for use in air-ground communication systems is still in a conceptual stage. The likely driving force for introducing a new air-ground communication system is the frequency congestion that is expected in particular in Europe around 2015 with in the VHF band (8.33 kHz channel spacing) and in the United States. Eurocontrol and the United States have agreed on a memorandum of cooperation on the development of a future air-ground communication system; one of the main objectives of this activity is to support the work of ACP Working Group C. High level system requirements are being discussed, and operational requirements to satisfy new applications derived from the new operational concept are under development. With regard to the development of SARPs and guidance material for the universal access transceiver (UAT), the progress of the work is on track for completion by mid-2005. In coordination with SCRSP, on-board compatibility between UAT and SSR and ACAS systems was assessed, and with regard to the compatibility with DME it was noted that utilization of the DME at the first adjacent channel from the UAT frequency would be possible.
Working Group F
Working Group F held two meetings, WG-/11 in February in Nairobi, Kenya, and WG-F/12 in August in Montreal, Canada. The meetings addressed the development of the draft ICAO position for the ITU WRC-2007. Significant amendments, as recommended by the NSP, included the removal from the ICAO position of an allocation to the aeronautical mobile (R) service in the bands used for ILS-Localizer/VOR, ILS-Glide Path and DME/SSR/RNSS. WG-F also extensively coordinated the ICAO submissions to the ITU Study Groups 8B, 8D and Task Group 1/8. Issues addressed were interference from ultra wide-band systems into aeronautical frequency bands and compatibility between GBAS and VDL mode 4 with FM broadcasting. WG-F also reviewed amendments to the Handbook on Radio Frequency Spectrum Requirements for Civil Aviation including Statement of Approved ICAO Policies (Doc 9718), necessary as a result of amendments to the ITU Radio Regulation as agreed at the ITU WRC-2003. Proposals for amending the ICAO radio frequency policy statements in the handbook were also developed. Work on a second volume of this Handbook addressing frequency assignment planning criteria and interference was started. Issues addressed were interference from broadband communication systems of power lines, use by passengers of mobile (cellular) telephones on board aircraft, use of personal electronic devices on board aircraft, and use of cellular base stations in the vicinity of aeronautical receivers (mainly on board an aircraft).
Working Group M
Working Group M held one meeting, WG-M/9, in October/November, partly in combination with WG-B. The progress achieved at the combined meeting with WG-B has been reported under the summary of activities for WG-B. WG-M further progressed the work on revising the AMSS SARPs, while incorporating the material developed at AMCP/7 for next-generation satellite systems. As a result, draft AMSS SARPs have been developed which contain only high level and regulatory material. Almost all of the current AMSS SARPs in Annex 10, Volume III (Chapter 4) has been proposed for incorporation in a manual. Similar manuals can be developed for other AMS(R)S systems, as and when necessary. WG-M also reviewed proposed amendments to the Manual on VHF Digital Link (VDL) Mode 3 (Doc 9805) and the Manual on VHF Digital Link (VDL) Mode 4 (Doc 9816).
Working Group N
Working Group N held two meetings, WG-N/3 in May in Montreal, Canada, and WG-N/4 in November in New Orleans, Louisiana, United States. In conjunction with these meetings, subgroup meetings were organized. The meetings addressed the ongoing implementation in different regions of TCP/IP rather than the standard ISO/OSI protocol suite, for ground-ground communication systems in the ATN, in particular for AMHS. An important factor is the industry moving away from OSI-based commercial products in favor of the worldwide acceptance of the Internet Protocol (IP). Ongoing implementation of air-ground ATN over VDL Mode 2, however, is based on the OSI protocols, as specified in the ICAO SARPs and guidance material. Working Group N is in the process of completing its report on the introduction of TCP/IP protocols in Annex 10 and related guidance material, as required, for review by a meeting of the ACP Working Group of the Whole in June/July 2005. The main goal of this activity would be to develop a recommendation to the ANC on the need for ACP to undertake further work in this area. Working Group N progressed work on PM-CPDLC material and reviewed the need for introducing an application level (end-to-end) checksum to the ICAO CPDLC messages with the view to provide for an end-to-end security mechanism operating completely separate from the VDL Mode 2 system. This measure would reduce the risks of undetected corrupted messages or their mis delivery. The work on AMHS profiles, with the goal of supporting binary data exchanges such as MET messages in BUFR format was further progressed. These activities are expected to be completed in 2005. Ongoing work in EUROCAE on the use of Voice over Internet Protocol (VoIP) is being monitored by Working Group N.