REPORT OF THE ICAO NSP SSG

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                                 International Civil Aviation Organization

                                 INFORMATION PAPER




            AERONAUTICAL COMMUNICATIONS PANEL (ACP)

                  21st MEETING OF THE WORKING GROUP/F

                          Bangkok, Thailand, 8 – 18 December 2009


Agenda Item 7: Any other business


                           REPORT
                           OF THE
          ICAO NSP SPECTRUM SUB-GROUP (SSG) MEETING
                  16th to 18th Nov. 2009, IATA Head Office, Montreal, Canada

                           (Presented by SSG rapporteur Felix Butsch)



                                         SUMMARY
          This information paper presents the report of the ICAO NSP Spectrum
          Subgroup (SSG), which took place from 16th to 18th November 2009 in
          Montreal, Canada.

          The following topics discussed by SSG may be the most relevant for WG/F:
           “Use of the band 112 – 117.975 MHz by VDL Mode 4
              - Updated results of tests and frequency assignment planning criteria”
              (WP8 of the SSG meeting)
           “GBAS in the frequency band 118 to 137 MHz”
              (WP42 of the SSG meeting)
           “Comments on WP4 MLS & AMS(R)S coexistence studies”
              (Flimsy9, rev.1 of the SSG meeting
I. Introduction

The meeting of the ICAO NSP Spectrum Sub-group (SSG) was held at the premises of the IATA
Head Office, Montreal, Canada from 16th to 18th November 2009. Mr. Felix Butsch, the rapporteur of
the SSG, chaired the meeting. The spectrum sub-group expressed its appreciation to the IATA for
hosting the meeting.

Attachment A of this report contains a list of action items and actionees. Attachment B provides a list
of participants. The following table contains an overview of agenda items with corresponding working
and information papers, which were discussed by the Spectrum Sub-group:
 WP/IP       Title                                                                     Presented to NSP by
 No.                                                                                   (Presented to SSG by)
 Agenda Item 6a): Signal and compatibility issues in the in the band 108 to 117.975 MHz
 WP8         Use of the band 112 – 117.975 MHz by VDL Mode 4 –                         ICAO secretariat
             Updated results of tests and frequency assignment planning criteria       (Larry Johnson and
                                                                                       Robert Witzen)
 WP44        Comments on WP8                                                           Tim Murphy
 Flimsy4     Recommended changes to the conclusions of NSP Nov09 WGW/WP8               (Andreas Lipp)
             “Use of the band 112 – 117.975 MHz by VDL Mode 4 - Updated
             results of tests and frequency assignment planning criteria
 Flimsy10    Comments on WP8                                                           (Joachim Wollweber)
 WP16        RFI Testing of Navigation Monitors (VOR and ILS)                          P. Salabert
                                                                                       (Gerhard Berz)
 WP38        Interference into ILS or VOR monitors                                     ICAO secretariat
                                                                                       (Robert Witzen)
 Flimsy18    Wideband ILS Monitor design                                               Jules Hermens
 WP13        Additional experimental data on VHF COM – VOR/ILS transmitter-to-         Vladimir Korchagin
             receiver isolation in the 108 – 137 MHz band for medium-sized aircraft    (Mikhail Markelov)
 WP42        GBAS frequency run using VHF communications criteria for in the           Ken Ashton
             frequency band 117.975 – 137 MHz                                          (Steve Mitchell)

 Agenda Item 6b): Signal and compatibility issues in the band 960 to 1215 MHz
 WP27        Way towards a Manual on characteristics of terrestrial navigation aids”   Stefan Naerlich
             - Attachment 1: Manual on characteristics of currently used terrestrial   (Joachim Wollweber)
             navigation aids - Chapter DVOR, VOR and VOT
             - Attachment 2: Manual on characteristics of currently used terrestrial
             navigation aids: - Chapter DME, DME/N, DME/P and TACAN
 WP39        Impact to GNSS from 1 GHz AM(R)S Unwanted RFI Emissions                   Leo Eldridge
                                                                                       (Robert Frazier,
                                                                                       Robert Erlandson)

 Agenda Item 6c): Signal and compatibility issues in the band 5000 to 5150 MHz
 WP4         MLS & AMS(R)S coexistence studies                                         ICAO secretariat
             - Attachment: MLS & AMS(R)S coexistence studies,
             (French input to CPG11/PTC-5, Geneva, September 2009)
 Flimsy9     Comments on WP4 MLS & AMS(R)S coexistence studies                         Jules Hermens

 Flimsy9,    Comments on WP4 MLS & AMS(R)S coexistence studies, reviewed               SSG rapporteur
 rev.1       by the SSG.




                                                 Page 2/18
Agenda Item 6d): GNSS signal and interference issues
WP3         Pseudolite implementation issues                                        Michel Calvet
                                                                                    (Olivier Outtier, Eric
                                                                                    Allaix, Benoît
                                                                                    Roturier)
WP6,        “ICAO Activities related to use of the Radionavigation-Satellite        ICAO secretariat
rev.1       Service for aeronautical radionavigation purposes”
            -Attachment: Note to the ICAO on “ICAO activities related to the use
            of Radionavigation Satellite Service for aeronautical Radionavigation
            Purposes”, Chairman, ITU-R Study Group 4”
Flimsy 13   Material supporting WP6                                                 Nikolay Shienok
Flimsy 14   Proposed ICAO response to questions raised by ITU SG4 chairman on       Robert Frazier
            RNSS usage in aviation, raised in WP6
Flimsy 14   Proposed ICAO response to questions raised by ITU SG4 chairman on       SSG rapporteur
rev.1       RNSS usage in aviation, raised in WP6,reviewed by the SSG

WP47        Impact of the proposed changes to GNSS antenna gain requirements on     Eric Chatre
            GALILEO                                                                 (Frederic Bastide and
                                                                                    Eric Chatre)

Agenda Item 6e): Open actions for the SSG from the ICAO NSP Working Group 1 meetings
            Note: No dedicated WPs or IPs have been presented under this agenda
            item.

Agenda Item 6 f): Spectrum – any other business
WP40        Proposed Amendments to Annex 10, Volume V                               Ken Ashton
            -Annex A: Proposed amendments as a results of provisions that have      (John Mettrop)
                      time expired
            -Annex B: Redundant text in Annex 10, Volume V
WP12        Problems with NDB Frequency Planning Criteria                           Stefan Naerlich
                                                                                    (Felix Butsch, Otto
                                                                                    Lindenau)
IP11,       IF-77 Conversion Process and Status                                     Leo Eldridge
rev.1                                                                               (John Tepper)




                                               Page 3/18
II. Results of the Discussions

Agenda Item 6a): Signal and compatibility issues in the in the band 108 to 117.975 MHz

WP8, “Use of the band 112 – 117.975 MHz by VDL Mode 4 –Updated results of tests and frequency
assignment planning criteria”
6a1) WP8 presented the results of testing of VDL Mode 4 with the view to establish frequency
     assignment planning criteria for the use of the band 112 – 117.975 MHz by VDL Mode 4 while
     protecting ILS, VOR and GBAS systems from harmful interference. The paper included results of
     testing performed in 2009. These tests included additional measurements of interference between
     VDL Mode 4 and VOR and GBAS as well as interference between VOR and GBAS. The paper
     also addresses comments made by the SSG at its last meeting. Finally preliminary frequency
     assignment planning criteria are proposed in section 7 of WP8.

Note: The discussion of WP8 is covered in this report after the description of the contents and
    discussion of all other papers dealing with VDL4-related issues.

WP44, “Comments on WP8”
6a2) WP44 made the SSG aware that ICCAIA circulated the working paper among avionics
     manufacturers asking for volunteers to review the paper and comment. Several engineers from
     Rockwell Collins International had reviewed the paper and documented comments which are
     contained in WP44.
 6a3) One of the main issues was the assumption on channel loading by VDL4 in WP8. The authors of
     WP8 clarified, that 2.7 % is a typical channel loading value for a single aircraft. However, also
     tests with 22 % and 50 % channel loading had been carried out. He pointed out, that background
     on assumed channel loading scenarios were already presented to ICAO ACP and could be made
     available to SSG.

Action SSG15/1: Robert Witzen to bring to the attention of SSG the channel loading scenarios were
    already presented to ICAO ACP

6a4) It was emphasized in WP44 that frequency planning criteria should not be based solely on
nominal observations of a few units under test. Units under test may perform better than MOPS
compliant units and have not been exercised under all relevant conditions. In WP44 it was pointed out,
that, while it is very good to conduct receiver susceptibility to interference testing, test results are not
sufficient to show the signal compatibility. Analytical models should be developed and exercised over
a wide range of conditions including the limiting cases that are usually not readily available during
testing. SSG members mentioned in this context that in general analytical are not a substitute for
testing.

6a5) Furthermore it was mentioned in WP44, that only a very limited cross-polarization could be
     expected between onboard VDL4 and ILS/VOR antennas. The author of WP8 clarified, that for
     the derivation of the proposed frequency planning criteria no cross-polarization isolation had been
     taken into account.

6a6) Another issue raised in WP44 was the out-of-channel spurious emissions of the VDL-4 test
     generator might be much lower, than that a minimally compliant VDL-4 transmitter, and VDL-4
     transmissions in the field might not be able to achieve the same results at some channel spacings.
     The authors of WP8 clarified that for the test a real VDL4 transmitter, not a clean signal generator
     had been used for the tests.

6a7) Moreover, it was questioned in WP44, whether 100 meters separation is actually a minimum
     separation between aircraft on the ground and aircraft on approach, multiple aircraft taxiing, and
     aircraft to the various ground stations. Several SSG members shared this concern during the
     discussion. It was mentioned in the discussion that, this can be addressed either through
     frequency planning or not allowing to use certain frequencies at an airport for VDL4.

                                                Page 4/18
6a8) Furthermore, the on-board compatibility of VDL-4 airborne transmissions was addressed in
     WP44. It was pointed out, that in particular for smaller airplanes, where antennas on the same
     side of the aircraft might see only 20 dB path loss (before polarization attenuation). Therefore
     such aircraft cannot be equipped with VDL4.

6a10) It was also pointed out in WP 44, that the ability for an aircraft to transmit VDL-M4 at a
    frequency in the traditional navigation band may cause the loss of integrity or continuity for
    receiving the desired navigation signal at the same frequency, should the transmitter inadvertently
    be tuned to a frequency that is being used for a navigation function. This concern was shared by
    all members of the SSG.

6a11) The SSG agreed that in particular the on-board compatibility issue and the issue of reduced
    continuity of navigations system which may be caused by a VDL4 transmitter inadvertently be
    tuned to a frequency that is being used for a navigation function should be further analyzed.

6a12) The SSG agreed, that requirements to implement mechanisms to prevent inadvertent tuning of
    VDL4 equipment to wrong frequencies should be introduced into the VDL4 SARPs. Such a
    mechanism need would need to have sufficient integrity to adequately protect the continuity
    requirements of ILS and VOR receivers, including receivers used by ILS/VOR monitors.

Actions SSG15/2: Robert Witzen to bring to SSG and ACP proposals how to change VDL4 SARPs to
    requirement to implement mechanisms to prevent inadvertent tuning of VDL4 equipment to
    wrong frequencies.

6a13) WP44 concluded that in general, the analysis of the data presented in WP8 appeared to be sound
    and valid to the extent that the assumptions are valid, and the equipment tested is representative"
    if not minimally compliant.

Flimsy4, “Recommended changes to the conclusions of NSP Nov09 WGW/WP8 “Use of the band 112
           – 117.975 MHz by VDL Mode 4 - Updated results of tests and frequency assignment
           planning criteria
6a14) In the context of the discussion of Flimsy4 the meeting noted, that the ITU Radio Regulations
    stipulate that the Aeronautical Radionavigation Service shall have priority over the Aeronautical
    Mobile Route Service in band 112 – 117.975 MHz.

6a15) In Flimsy4 it was emphasized that various elements in the recommendations of WP8 containing
    guidance to states introducing VDL4 conflict with the prerogatives cited from the ITU regulation
    and Resolution 413. For this reason changes to these recommendations were proposed in
    Flimsy4. As paragraphs 6a10) to 6a12) of this report state the concerns voice in Flimsy4 have
    captured in an action (below paragraph 6a12). Therefore, the proposed changes to
    recommendations in WP8 contained in Flimsy4 are obsolete.

Flimsy10, “Comments on WP8”
    6a15) Flimsy10 questioned some of the assumptions made for the tests mentioned in WP8. It was
    mentioned in Flimsy 10, that e.g. receiver selectivity and signal processing may differ between
    receiver types and consequently result in different interference behavior, It further recommended
    to limit the absolute EIRP of VDL4.

6a16) Flimsy 10 was presented without adequate time for discussion. Therefore, it was recommended
    by the SSG to re-submit the contents at a further meeting.




                                               Page 5/18
6a17) Some members of the SSG informed the group, that the material contained in Flimsy10 did not
    contain sufficiently material supporting the recommendations in Flimsy10. The ICAO secretary
    suggested that the material to be re-submitted to the SSG be vetted by the author for relevance to
    the work of the group and contains specific proposals on how address any issues highlighted.
    Furthermore, the materials should be submitted in time to allow adequate review before the
    meeting.

WP16, “RFI Testing of Navigation Monitors (VOR and ILS)”
6a18) From the presentation of WP16, the SSG noted that one concern raised in the discussion around
    the introduction of planning criteria for VDL Mode 4 service in the navigation band focused on
    potential interference problems caused by aircraft transmitters when operating (taxiing) near VOR
    and ILS ground facilities (WP5 of the March 2009 WGW meeting in France). This papers reports
    on some preliminary interference tests that have been conducted recently, including a discussion
    of issues relating to the introduction of VDL-4 in the VHF NAV band in general.

6a19) WP16 concluded that initial tests show that compatibility between VOR and ILS ground facility
    monitors and VDL-4 would need to be investigated further in detail, as even intermittent levels of
    -25dBm at the monitor antennas could have an impact clear across the entire band. It had also
    been shown that tuning failures, which would produce in-band RFI, can significantly affect the
    DDM of ILS signals received by the monitor, as well as the azimuth decoding of the VOR signal
    by the monitor.

6a20) During the discussion of WP16, all SSG members agreed, that the protection of ILS/VOR
    monitors against interference by VDL4 transmission is of utmost importance. Some members of
    the SSG pointed out, that it would be desirable. If ILS/VOR monitors contained narrow band
    filters this could help to prevent interference not only by VDL4, but also by other signals, like
    FM broadcast and aeronautical radiocommunication in the adjacent band. This would also allow
    to prevent interference by other sources, like FM broadcast or adjacent band aeronautical
    radiocommunication.


WP38, “Interference into ILS or VOR monitors”
6a21) WP38 contained a preliminary assessment of separation distances that may be necessary to
    protect these broadband monitors from such interference by VDL4 transmitters. It concluded that
    aircraft in flight (at least 1000 ft separated) would not cause harmful interference to ILS or VOR
    monitors, with the possible exception of VORs and ILSs directly overflown in proximity.
    However, aircraft on the airport surface could be causing interference to monitors with their
    VDL4 transmission at distances between 150 and 200 m.

6a22) In the discussion various members of the SSG were of the opinion that protection of ILS/VOR
    monitors should not be part of the frequency coordination for VDL4. It would rather be a task for
    national authorities authorizing VDL4 operation to establish regulations ensuring the necessary
    protection of ILS/VOR monitors.

Action SSG15/3: ICAO secretary to bring the identified interference susceptibility of broadband
    ILS/VOR monitors to the attention of CN&TSG.

Action SSG15/4: SSG members to contribute to the further analysis of the interference susceptibility
    of broadband ILS/VOR monitors.




                                              Page 6/18
Flimsy18, “Wideband ILS Monitor design”
6a23) Flimsy18 was just presented for information of the group. Due to lack of time, it could not be
    discussed. However, its author was encouraged to re-submit it to the next meeting.

Note: The following paragraphs summarize the discussion of WP8, WP44, Flimsy4, Flimsy10, WP16
and WP38 as announced above:

6a24) After the presentations of WP8, WP44, Flimsy4, Flimsy10, WP16 and WP38 a general
    discussion on the preliminary frequency planning criteria contained in WP8 took place.
      The SSG agreed that the following major issues need to be further analyzed:
       The on-board compatibility issue.
       The issue of reduced continuity of navigations system which may be caused by a VDL4
        transmitter inadvertently be tuned to a frequency causing interference to a navigation function
       The compatibility between VDL4 and ILS/VOR monitors.

6a25) However, the SSG was of the opinion, that these open issued should not prevent the SSG to
    endorse adoption of the preliminary frequency planning criteria contained in WP8.

6a26) It was agreed that SSG encourages approval of these preliminary frequency planning criteria by
    ICAO ACP, only under the condition that the aforementioned open issues are adequately
    addressed.

WP13, “Additional experimental data on VHF COM – VOR/ILS transmitter-to-receiver isolation in
       the 108 – 137 MHz band for medium-sized aircraft”

6a27) WP13 presented additional experimental data on the isolation between onboard VHF COM
    transmitters and VOR/ILS receivers collected on medium-sized Antonov family aircraft. It
    concluded that it is reasonably safe to suggest that minimal value of transmitter-to-receiver
    isolation for typical antenna locations on medium-sized aircraft is in the order of 40 dB. It was
    also mentioned that the Russian airworthiness authority requires 35 dB isolation between
    antennas onboard aircraft.

6a28) The SSG deemed it desirable to obtain additional information related to minimum isolation
    between antennas onboard medium-sized and small aircraft to be able to take these data into
    account for further compatibility analyses. SSG members mentioned that related information is
    already contained in WP44. Furthermore one SSG member mentioned that ARINC 716 may also
    contain relevant isolation data.

Action SSG15/5: To provide information on airworthy requirements in their states requiring minimum
    isolation between aircraft antennas


WP42, “GBAS in the frequency band 118 to 137 MHz”

6a29) In response to Action SSG14/9 from last SSG meeting WP42 presented results of a simulation
    of the attainable GBAS frequencies in the band 118 to 137 MHz. For this purpose, the operational
    coverage area of GBAS was modeled as a circular aeronautical communications broadcast service
    with a range of 25 NM and 10000 ft ceiling. The European MANIF frequency planning tool with
    a VHF communications database (117.975-137 MHz) dated 28 October 2009 was used applying
    frequency coordination criteria for VHF COM systems as documented in the European ICAO
    Frequency Management Manual (Doc 011). Planning runs were undertaken for GBAS both as a
    Ground-Air (GA) and an Air-Ground-Air (AGA) service for each of the airports identified. The
    AGA planning run was only to illustrate the reduced constraints, when frequencies for ground
    transmissions only are searched.



                                               Page 7/18
6a30) It was pointed out that, although the VHF communications frequency band in European “core”
    area is near capacity for Air-Ground-Air purposes there are still opportunities for broadcast type
    services (Ground-Air). This is due to the limiting factor being the air to ground element and not
    the ground to air element. For major European airports like Heathrow, Frankfurt, Paris, where
    almost no new Air-Ground-Air frequency could be assigned, it turned out, that between 4 and 25
    frequencies for a broadcast service like GBAS could be found.

6a31) Although the presented results were quite plausible, members of the SSG emphasized that fewer
    usable frequencies for GBAS would have been found, if during the planning exercise a frequency
    would have been assigned to an individual location, before a search for a new location would
    have been started. Other SSG members pointed out, that the possibility of simultaneous on-board
    operation of a VHF communication transmitter and a GBAS receiver in the same band has not yet
    been analyzed in detail.

6a32) The SSG agreed to encourage further analysis of the benefits of using the VHF communication
    band for GBAS taking into account the actual planning criteria specification for GBAS according
    to the ICAO SARPs. Furthermore, SSG agreed do carry out further work to analyze on-board
    compatibility issues of GBAS.

Actions SSG15/6: Steve Mitchell to further analyze of the benefits of using the VHF communication
    band for GBAS taking into account the actual planning criteria specification for GBAS according
    to the European ICAO Frequency Management Manual (Doc 011).

Actions SSG15/7: Tim Murphy to present available data on isolation between on-board VHF
    radiocommunication and VHF navigation antennas.

Agenda Item 6b): Signal and compatibility issues in the band 960 to 1215 MHz

WP27, “Way towards a Manual on characteristics of terrestrial navigation aids”
      - Attachment 1: Manual on characteristics of currently used terrestrial navigation aids
                      - Chapter DVOR, VOR and VOT
      - Attachment 2: Manual on characteristics of currently used terrestrial navigation aids
                      - Chapter DME, DME/N, DME/P and TACAN

6b1) The SSG noted from the presentation of WP27 that the aim of this document is to further pursue
    the task to develop a “manual-like” ICAO document containing the information of system
    characteristics of the currently used DME, TACAN, VOR and DVOR systems. The SSG was
    reminded that it agreed at its March 2007 meeting in Delhi that the material prepared by the “Ad
    Hoc Group on DME and VOR coverage”, shall be further evolved.

6b2) After a short presentation of the attachments of WP27 containing drafts of chapters for a manual
    on characteristics of currently used terrestrial navigation aids a discussion took place. The group
    agreed, that the presented material was very valuable and the goal to develop a manual on
    characteristics of terrestrial navigation aids is desirable.

6b3) The ICAO secretary pointed out, that the panel had not been tasked to do this work. Furthermore,
    various ways for collaboration by correspondence on the development of such a manual were
    discussed. In this context the chairman of ICAO EANPG FMG offered that the FMG study group
    could dedicate some time and effort to this goal. The ICAO secretary welcomed this offer and
    suggested that the result of the FMG development in due course should be brought to the
    attention of the NSP.




                                               Page 8/18
WP39, “Impact to GNSS from 1 GHz AM(R)S Unwanted RFI Emissions”

6b4) WP39 made the SSG aware, that ITU-R Working Party 5B (WP 5B) produced an interim draft
    RFI analysis report summarizing its work to date on assessing 960-1164 MHz frequency band
    sharing feasibility for aeronautical mobile (Route) service (AM(R)S). ITU-R WP4C reviewed the
    section of that report on impact from AM(R)S unwanted emissions on GNSS receiver operation
    above 1164 MHz and raised concerns about several aspects. Building on the WP 4C formal
    comments, this working paper proposes specific changes in the WP 5B report analysis method
    and provides revised analyses for two specific cases based on AM(R)S technical characteristics
    listed in the WP 5B interim draft report.

6b5) The NSP SSG reviewed the findings presented in WP39 and encouraged to forward the content
    of WP39 to ICAO ACP and to ITU-R WP 5B.

Action SSG15/8: ICAO secretary to bring SSG15/WP39 to the attention of ICAO ACP WG/F


Agenda Item 6c): Signal and compatibility issues in the band 5000 to 5150 MHz

WP4, “MLS & AMS(R)S coexistence studies”
     - Attachment: MLS & AMS(R)S coexistence studies, (French input to CPG11/PTC-5, Geneva,
     September 2009)

6c1) WP4 informed the SSG, that the attached paper was presented to a recent CEPT meeting (CEPT
     CPG PT C). It addresses the possible use of the band 5 030 – 5 091 MHz jointly by the
     Microwave Landing System (MLS) and the Aeronautical Mobile Satellite (Route) Service
     (AMS(R)S). It provides background information as well as on the methodology and the scenarios
     to be used to determine, how this band can be used jointly by MLS and the proposed AMS(R)S
     systems.

6c2) One member of the group reviewed the attachment of WP4. He presented his comments and
     change proposals to the SSG as Flimsy 9. Flimsy 9 was then discussed and slightly modified by
     the SSG. The agreed version is contained in rev.1 of Flimsy 9.

6c3) Members of the SSG mentioned, that an input paper presenting similar material as the
     aforementioned PT-C document had been announced for the upcoming ITU WP5B meeting. It
     was pointed out, that the deadline of submissions for this meeting had already been passed.
     However, other members of the SSG pointed out that the comments and change proposals
     contained in Flimsy 9 could a least support verbal comments of ICAO representatives attending
     ITU 5B. It may also be useful as input to other meetings e.g. of ICAO ACP WG/F and CEPT
     PT-C dealing with the same subject.

Action SSG15/9: ICAO secretary to use SSG14/Flimsy 9, rev.1 as a basis to comment inputs to ITU
    WP5B on MLS & AMS(R)S coexistence studies

Agenda Item 6d): GNSS signal and interference issues

WP3, “Pseudolite implementation issues”
6d1) WP3 pointed out, that it has been proposed recently by a French company to develop Pseudolites
     for indoor localization, which would transmit signals in the GPS L1 frequency band using PRN
     Codes of existing GPS satellites, which are below the horizon. The expected market would be
     large shopping centres, railway stations, exposition centres or airport terminals. WP3 raised
     concerns about the interference risks toward aeronautical GNSS receivers. WP3 also questioned
     that the compatibility criteria for Pseudolites stipulated in the recently adopted ECC report 128
     were sufficient to protect aeronautical GNSS receivers.


                                              Page 9/18
6d2) The members of the SSG emphasized, that it is very important to ensure adequate protection of
     aeronautical receivers against interference by such Pseudolites. Therefore, it agreed with the
     recommendations in WP3 that is would be desirable:
    To share information on Pseudolites project potentially leading to proliferation of ground
        transmitting RNSS sources in their country or region,
    To share information on the regulatory framework applicable to their country or region,
    To provide in suitable time feedback on the proposed European regulation.

6d3) Furthermore, the SSG pointed out, that it would be desirable for SSG members to contribute the
     aviation point of view to the ongoing work in the CEPT working groups SE40 (dealing with the
     compatibility studies of such Pseudolites) and FM44 (developing the new EU regulations for the
     frequency usage by such Pseudolites). Steve Mitchell (NATS) volunteered to act as a focal point
     to provide information from dedicated CEPT working groups SE40 and FM44 to ICAO NSP.

Action SSG15/9: SSG members to contribute to the work of CEPT working groups dealing with the
     frequency compatibility of Pseudolites and to exchange information on the regulations for
     Pseudolites
Action SSG15/10: Steve Mitchell to act as a focal point to provide information from dedicated CEPT
     working groups SE40 and FM44 to ICAO NSP.


WP6, rev.1, “ICAO Activities related to use of the Radionavigation-Satellite Service for aeronautical
            radionavigation purposes”
            -Attachment: Note to the ICAO on “ICAO activities related to the use of Radionavigation
            Satellite Service for aeronautical Radionavigation Purposes”, Chairman, ITU-R Study
            Group 4”, ITU-R, Document 4/ICAO-E, 26 October 2009

6d4) WP6 presented a note which ICAO received from the Chairman of ITU-R Study Group 4. In the
note it was pointed out, there were questions raised about the use of RNSS for aeronautical
radionavigation applications and the need for an extra 6-dB protection margin. It addresses to ICAO a
number of questions related to the use of GNSS by aviation.

6d5) The SSG discussed the questions by Chairman of ITU-R Study Group 4. One member of the
group drafted potential answers of ICAO to these questions, which are contained in Flimsy 14. Then
the SSG reviewed and modified slightly the proposed answers. The agreed version is contained in
rev.1 of flimsy 14. The ICAO secretary informed the SSG that rev.1 of Flimsy 14 was in the meantime
further reviewed by the GSSG. The output of GSSG is contained in rev.2 of Flimsy14. This version
will be forwarded to ICAO ACP WG/F for further discussion with the final goal to have it submitted
to ITU SG4.

Flimsy 13, “Material supporting WP6”
6d6) Flimsy 13 contains various excerpts of ITU WP4C documents addressing background and
current situation with Draft New ITU-R Recommendations related to RNSS. This material was only
presented for information to NSP members. I was not discussed by the SSG.


WP47, “Impact of the proposed changes to GNSS antenna gain requirements on GALILEO”
6d7) WP47 was discussed by a joint session of the GSSG and SSG. WP47 reminded the meeting that
WP56 (Montreal, 2006) proposed a change to GNSS antenna gain requirements (Annex 10, Volume 1,
Appendix B, Table B-87) to accommodate the new RTCA DO-301 active GNSS antenna standard
within the ICAO SARPs. The main change concerns the minimum antenna gain at 5 degrees elevation
angle which is proposed to be reduced from -4.5 dB to -5.5 dB.




                                             Page 10/18
6d8) It was demonstrated in WP47, that decreasing the minimum required user antenna gain at 5
degrees from -4.5 dB to -5.5 dB would cause a negative link-budget margins for Galileo E1 and
E5a/E5b. During the discussion, it was assured to the meeting by the author of WP47, that it could be
also demonstrated, that it would be possible to manufacture a two-frequency antenna for Galileo
which would provide the desired gain of -4.5 dB at 5 degrees elevation for all azimuth angles.

6d9) The meeting agreed, that based on the information contained in WP47existing ICAO GNSS
antenna gain requirements shall not be changed. The meeting recommend to bring the new available
material on the feasibility of a two-frequency GNSS antenna achieving the gain of -4.5 dB required by
ICAO to the attention of EUROCAE WG62 and RTCA SC159 to discuss the impact on the GNSS
receivers MOPS.

Action SSG15/11: Eric Chatre to bring the new available material on the feasibility of a two-
frequency GNSS antenna achieving the gain of -4.5 dB required by ICAO to the attention of
EUROCAE WG62 and RTCA SC159 to discuss the impact on the GNSS receivers MOPS.


Agenda Item 6e): Open actions for SSG from the ICAO NSP Working Group 1 meetings

Note: No dedicated WPs or IPs have been presented under this agenda item.


Agenda Item 6f): Spectrum – any other business

WP40, “Proposed Amendments to Annex 10, Volume V”
      -Annex A: Proposed amendments as a results of provisions that have time expired
      -Annex B: Redundant text in Annex 10, Volume V

6f1) This paper proposed a number of editorial amendments to Annex 10 Volume V to take into
     account recent developments. While Annex A of WP40 contained proposed amendments as
     results of provisions that have time expired, Annex B proposed deletion of redundant text.

6f2) The SSG agreed with the proposed changes. However, it was recommended, that before the
     changes of section 4.2.4 and bullet C) of section 4.2.3.1, dealing with 100 kHz channel spacing of
     VOR, are adopted by ICAO NSP, other NSP groups like CN&TSG should assess the impact.
     Furthermore ICAO secretary should bring the proposed changes to the attention of various ICAO
     regions, which may still VOR receivers with 100 kHz channel spacing.

Action SSG15/12: ICAO secretary to make CN&TSG aware of the proposed changes to Annex 10,
    Volume V contained in SSG15/WP40

Action SSG15/13: ICAO secretary to make ICAO regions, where still 100 kHz channels spacing may
    be used for VOR, aware of the proposed changes to Annex 10, Volume V contained in
    SSG15/WP40


WP12, “Problems with NDB Frequency Planning Criteria”
6f3) WP12 reported that in Germany, several cases of interference by undesired NDB signals occurred
     in recent years. Each time the identification of NDBs operating on adjacent channels were heard
     clearly and lead to confusion of the pilots. Investigations lead to the conclusion that although a
     considerable number of “old” ADF receivers with broad selectivity characteristics are still in use,
     while the frequency coordination procedures are already based on a narrow ADF receiver
     selectivity curve, which is typical for “modern” ADF receivers.




                                              Page 11/18
6f4) The SSG members were convinced by the presented evidence that frequency coordination criteria
     based on the new ADF receiver selectivity curves in section 3 of ICAO Annex 10, Vol. V, Att. B
     is not sufficient to protect old ADF receivers. Therefore, the SSG agreed to recommend to ICAO
     regions that NDB frequency coordination criteria should be based on the “old” ADF receiver
     selectivity curves, where “old” ADF receivers are still in use.

IP11, rev.1, “IF-77 Conversion Process and Status”
6f5) IP11 presented new information about FAA activities in the context of converting the FORTRAN
      implementation of the IF-77 propagation model to an ANSI C version, which can be operated on
      a personal computer using a Windows operating system. Moreover, this document discussed the
      motivation behind the effort, the steps taken to perform the conversion, information about the
      model, and operation of the new version.
      The SSG noticed that future efforts will focus on the completion, testing of the all variables on
      the “environment” tab as well as to incorporate more contour curves from FAA’s Spectrum
      Management Regulations and procedures Manual (Order 6050.32B) for comparison and
      verification. A future version of the software would also allow to include user-defined aircraft
      antenna patterns.

6f6) SSG members were invited to test a trial version of the program and to provide feedback to FAA
     (john.tepper@faa.gov).

Action SSG15/14: SSG members to test the latest trial version of FAA’s new implementation of the
IF-77 propagation model and to provide feedback to FAA.

III     Administrative maters
An updated action item list of the SSG can be found as Attachment B of this report. The next meeting
of the Spectrum Sub-group is expected to take place in conjunction with the next ICAO NSP meeting
in Mai 2010.

ATTACHMENT A: ACTION ITEM LIST
 Action       Action                                 Actionees           Status
 number
 Actions from the Montreal meeting October 2005 (SSG8):
 SSG8/2       Present results of FMG on improved     DFS                 Ongoing
              coordination criteria for conventional                     (see SSG/10, IP2)
              nav aids to SSG.
 SSG8/5       Prepare text for the RF handbook on    Secretary           Discarded
              potential interference to GNSS by
              commercial broadcast

 Actions from the Brussels meeting May 2006 (SSG9):
 SSG9/15      To undertake measurements to          SSG members          Open
              investigate the impact of noise-like
              signals (AMT, FSS, RNSS) on the
              performance of MLS receivers.

 Actions from the Montreal meeting October 2006 (SSG10):
 SSG10/1      Robert Frazier (US) to further clarify the US              Ongoing
              reason for “discontinuities” in the DME
              propagation curves.
 SSG10/8      To provide results of GBAS vs. ILS         Christophe      Open
              bench tests carried out by STNA in         Dehaynain
              2004.                                      (France)
 SSG10/9       To present bench test results to          SSG             Open
              determine the interference threshold of
              VHF COM and ILS against GBAS
              signals.



                                               Page 12/18
SSG10/10    To develop more detailed frequency         SSG               Open
            coordination criteria between GBAS and
            VHF-COM as well as GBAS and ILS
            for publication by ICAO.
SSG10/11    To explore impact of change of             Joachim           Open
            propagation model in the guidance          Wollweber
            material for the frequency co-ordination   (Germany)
            of GBAS (section 7.2.1.3.3 of
            Attachment D to Volume 1 of ICAO
            Annex 10, and Tables D3 and D4.) and
            to draft a proposed revised version.

SSG10/12    To review the GBAS SARPS changes in        SSG               Open
            WP23 (GBAS Positioning Service), in
            order to investigate the need of
            necessary changes of the guidance
            material, taking also in to account
            potential decisions of CSG on WP23.

Actions from the Delhi meeting March 2007 (SSG11):

SSG11/x     To present a proposal of detailed          DME/VOR           Discarded
            guidance material on DME coverage          coverage ad-hoc
            volume to be included in a new volume      group
            of the ICAO RF-handbook, ICAO DOC
            9718.
SSG11/2     To present a proposal of detailed          DME/VOR           Discarded
            guidance material on VOR coverage          coverage ad-hoc
            volume to be included in a new volume      group
            of the ICAO RF-handbook, ICAO DOC
            9718.

Actions from the Montreal meeting March 2008 (SSG12):

SSG12/a     To support adequate protection of          SSG members       Completed
            GLONASS within an RTCA Special
            Committee which works on RTCA DO-
            210D.
SSG12/4     To present the information contained in    France            Ongoing
            WP12 to future ICAO ACP WG/F
            meetings and or ACP WGW meetings,
            to point out the need to develop an I/N
            protection ratio for the FRS for the
            discussion of the compatibility between
            the Future Radio System and UMTS
            within CEPT regional radio regulatory
            organisations.
SSG12/6     To carry out measurements of the           SSG members       Open
            susceptibility of aeronautical receivers                     Partly fulfilled by IP9 of SSG13.
            working in the band 108 and 137 MHz
            (ILS, VOR, GBAS, AM) to interference
            by new VHF broadcast signals, with as
            many aeronautical receiver types as
            possible.
SSG12/7     To keep SSG informed about the latest      SSG members       Open
            results of discussions of the com-
            patibility between digital broadcast and
            aeronautical systems in the VHF band.




                                              Page 13/18
Actions from the Montreal meeting October 2008 (SSG13):
SSG13/1      To present a paper on “Joint use of the   ICCAIA          Open
             band 5030 to 5150 by the Microwave
             Landing System (MLS) and the
             Aeronautical Mobile Satellite (en Route)
             Service (AMS(R)S)” to future ICAO
             ACP WGW and WG/F meetings.
SSG13/3      To present a revised version of the WP    Robert Witzen   Open, Partially fulfilled by WP5
             “Use of the band 112 to 117.975 MHz                       to SSG/14,
             by VDL Mode 4 - Results of tests and                      Partially fulfilled by WP8 to
             frequency assignment planning criteria”                   SSG/15
             taking into account comments by
             SSG/13 and information on the
             Eurocontrol VDL Mode 4 avionics
             architecture study contained in
             SSG13/IP24.
SSG13/5      To provide measurement results of DME SSG members         Open
             spurious emissions in the RNSS bands
             (GPS L5, Galileo E5, Glonass L3 band)
             to establish the need for a change of
             DME MOPS.
SSG13/8      To present at a future NSP meeting an     SSG members     Accomplished by WP47 of
             analysis of the impact of the change of                   SSG/15
             GNSS antenna specification for the link-
             budget.
SSG13/9      To propose a short additional text for    Germany         Open
             ICAO Annex 10, Vol. I, Attachment C,
             recommending that in frequency-
             congested areas more refined calculation
             of the required separation distance for
             ILS based on additional parameters like
             transmitter power, antenna gain, antenna
             directivity and antenna orientation is
             recommended.
Actions from the Bretigny meeting March 2009 (SSG14):
SSG14/5      To provide measurement results on         SSG members     Open
             transmitter-to-receiver isolation
             achievable on medium, small and light
             aircraft for VDL Mode 4 compatibility
             studies.
SSG14/6      To ask CSG to provide the reference       Andreas Lipp    Overtaken by events
             document containing the derivation of
             the allowable GBAS VDB message error
             rate requirement.
SSG14/7      To provide further test results of VDL4   Robert Witzen   Fulfilled by SSG15/WP8
             compatibility studies
SSG14/8      To present a WP to a future SSG           Gerhard Berz    Closed by SSG15/WP16
             meeting addressing the interference
             threat between VDL-4 and VOR as well
             as ILS monitors.
SSG14/9      To carry out a simulation of the          UK              Closed by SSG15/WP42
             attainable GBAS frequencies in the band
             118 to 137 MHz using the MANIF
             software and modeling GBAS as a
             circular broadcast service with a range
             of 23 NM.
SSG14/10     To provide the Oct. 2009 meeting of       Eric Chatre     Closed by SSG15/WP47
             SSG material solution of the issue of the
             proposed revision of the GNSS antenna
             specification in ICAO Annex 10.

                                             Page 14/18
SSG14/11     To carry out compatibility                  SSG members   Open
             measurements between digital sound-
             broadcasting in the band of about 87-108
             MHz and aeronautical services in the
             band 108-117.975 MHz and to
             contribute to the development of
             protection criteria.
SSG14/12     To seek clarification from WGW about        Secretary     Open
             the meaning of the task “To develop
             guidance material to assist States facing
             an environment with a high level of
             interference to SBAS GEO satellites
             operating at the minimum signal strength
             specified by SARPs.”
SSG14/13     SSG members to try-out the test-version     SSG members   Superseded by a new action
             of new IF77 software and provide feed-
             back to FAA
Actions from the Montreal meeting November 2009 (SSG15):
SSG15/1      To bring to the attention of SSG the     Robert Witzen
             channel loading scenarios were already
             presented to ICAO ACP
SSG15/2      To bring to SSG and ACP proposals        Robert Witzen
             how to change VDL4 SARPs to
             requirement to implement mechanisms
             to prevent inadvertent tuning of VDL4
             equipment to wrong frequencies.
SSG15/3      To bring the identified interference     ICAO secretary
             susceptibility of broadband ILS/VOR
             monitors to the attention of CN&TSG.
SSG15/4      To contribute to the further analysis of SSG members
             the interference susceptibility of
             broadband ILS/VOR monitors.
SSG15/5      To provide information on airworthy      SSG members
             requirements in their states requiring
             minimum isolation between aircraft
             antennas
SSG15/6      To further analyze of the benefits of    Steve Mitchell
             using the VHF communication band for
             GBAS taking into account the actual
             planning criteria specification for GBAS
             according to the European ICAO
             Frequency Management Manual (Doc
             011).
SSG15/7      To present available data on isolation   Tim Murphy
             between on-board VHF
             radiocommunication and VHF
             navigation antennas.
SSG15/8      To bring SSG15/WP39 to the attention     ICAO secretary
             of ICAO ACP WG/F
SSG15/9      To use SSG14/Flimsy 9, rev.1 as a basis ICAO secretary
             to comment inputs to ITU WP5B on
             MLS & AMS(R)S coexistence studies




                                               Page 15/18
SSG15/10   To contribute to the work of CEPT           SSG members
           working groups dealing with the
           frequency compatibility of Pseudolites
           and to exchange information on the
           regulations for Pseudolites
           Action SSG15/10: Steve Mitchell to act
           as a focal point to provide information
           from dedicated CEPT working groups
           SE40 and FM44 to ICAO NSP
SSG15/11   to bring the new available material on      Eric Chatre
           the feasibility of a two-frequency GNSS
           antenna achieving the gain of -4.5 dB
           required by ICAO to the attention of
           EUROCAE WG62 and RTCA SC159 to
           discuss the impact on the GNSS
           receivers MOPS.
SSG15/12   To make CN&TSG aware of the                 ICAO
           proposed changes to Annex 10, Volume
           V contained in SSG15/WP40
SSG15/13   To make ICAO regions, where still 100       ICAO secretary
           kHz channels spacing may be used for
           VOR, aware of the proposed changes to
           Annex 10, Volume V contained in
           SSG15/WP40
SSG15/14   To test the latest trial version of FAA’s   SSG members
           new implementation of the IF-77
           propagation model and to provide
           feedback to FAA.




                                             Page 16/18
ATTACHEMENT B: LIST OF PARTICIPANTS OF THE SSG
                      Atten-
Name                           Organisation            Telephone            Email
                      dance

Alessandro Capretti   P        ICAO Secretariat        +1-514-954-5847      acapretti@icao.int

                                                       +33 (0)1 6988
Andreas Lipp          F        EUROCONTROL                                  andreas.lipp@eurocontrol.int
                                                       7618/7307

                               DGAC/DSNA,
Benoit Roturier       P                                                     Benoit.roturier@aviation-civile.gouv.fr
                               France

                               ICCAIA / Airbus,
Dominique Pomies      P                                +33-561-938-675      Dominique.Pomies@Airbus.com
                               France

                               European
Eric Chatre           P                                +32-229-64-776       eric.chatre@ec.europa.eu
                               Commission

Felix Butsch          F        DFS, Germany            +49 6103-707-1533    Felix.Butsch@dfs.de


Gerhard E. Berz       P        EUROCONTROL             +32 2 729 3734       gerhard.berz@eurocontrol.int


Jason Burns           P        FAA, USA                +1-202-267-9403      Jason.Burns@FAA.gov


Joachim Wollweber     F        DFS, Germany            +49 6103-707-1531    Joachim.Wollweber@DFS.de


John Mettrop          P        CAA UK                  +44(0)20 7453 6531   John.Mettrop@caa.co.uk.


John Taylor           F        Transport Canada        +1-613-993-4061      John.Taylor@TC.gc.ca


John Tepper           F        FAA, USA                                     John.Tepper@faa.gov

                               Netherlands Civil
Jules Hermens         P                                +31 70 456 3268      Jules.Hermens@ivw.nl
                               Aviation Authority

Larry Johnson         F        LFV, Sweden             +46-708-151-381      Larry.Johnsson@LFV.se


Lofter Jonasson       P        ICAO                    +1-514-954-8219      LJonasson@ICAO.INT

                               Airnavigation
                               State Scientific &
Mikhail Markelov      F                                +7(495)-490-95-84    Markelov@atminst.ru
                               Research Institute,
                               Russia
                               Geyser Scientific
Nikolay Shienok       F        & Production Co.        +7(495) 784-63-30    Shienok@geyser.ru
                               Russia
                               European
Pauls Nisner          F                                +44-776-972-4864     Paul.Nisner@NATS.co.UK
                               Commission

Robert Frazier        F        FAA, USA                +1-202-267-9722      Robert.Frazier@FAA.GOV

                               ICAO Technical
Robert Witzen         F                                +1-514-4267654       r.witzen@videotron.ca
                               Advisor

Steve Mitchell        F        NATS, UK                +44-1489-444646      Steve.mitchell@nats.co.uk



                                                     Page 17/18
Tim Murphy              P        ICCAIA/Boeing     +1-425-294-0038   tim.murphy@boeing.com


Note: P/F = Part time/Full time attendance




                                                 Page 18/18