.
Agenda Item xx
Comments and proposed modifications to the paper:
proposed revision of dme sarps as a consequence of uat standardization
(Developed by ACP WGC UAT Subgroup)
(Presented by Mike Biggs)
(Prepared by Joachim Wollweber)
(Presented by Felix Butsch)
Summary
The use of “DME” in ANNEX 10 includes whenever not specifically stated otherwise DMEN, DME-P and ICAO compliant use TACAN (Tactical Air Navigation). In addition to standalone use frequency pairing of DME with VOR, ILS and MLS is defined in Annex 10, Table A DME channeling and pairing.
A footnote in Table A for 108.00 MHz and 17x has not been changed to reflect the actual use since 1959 (Doc7973-COR1, III23) and also lacks definition and guidance for the so called “emergency service”. Regions that have a frequency congested area, e.g. like Europe, have used 108.00 for VOT or VOR and channel 17x for operational DME and TACAN well before 1974 as can be shown in the first available Paris office COM List No 2 from October 1974.
Note: To highlight the requirements of frequency congested regions as well as those that seek to implement GBAS, the following changes are proposed and highlighted in Bold Arial, while the original in the original paper remains in the original format in Times New Roman.proposed revision of dme sarps as a consequence of uat standardization
(Developed by ACP WGC UAT Subgroup)
(Presented by Mike Biggs)
Summary
Compatibility between distance measuring equipment (DME), ICAO compliant use of TACAN (Tactical Air Navigation)and the Universal Access Transceiver (UAT), and the resultant frequency planning criteria, have been developed and agreed by the Aeronautical Communications Panel and the Navigation Systems Panel (NSP). To highlight the resultant spectrum sharing between DME and UAT, two modifications to the existing DME Standards are proposed.
1.0Introduction
1.1International Civil Aviation Organization (ICAO) Standards and Recommended Practices (SARPs) for the Universal Access Transceiver (UAT) are currently under development by Working Group C of the Aeronautical Communications Panel (ACP). Since the UAT operating frequency, 978 MHz, is currently part of the channel plan of ICAO-standard UHS Distance Measuring Equipment (DME)and ICAO compliant use of TACAN (Tactical Air Navigation), compatibility with DME and the resultant channel planning criteria have been developed and agreed in coordination with the Navigation Systems Panel (NSP). To highlight the resultant spectrum sharing between DME and UAT, two modifications to the existing DME SARPs are proposed.
2.0Proposed Change Number 1
2.1The DME channel plan is outlined in Table A:DME/MLS angle, DME/VOR DME/ILS/MLS channeling(DME includes DME-N and DME-P as well as the use of ICAO compliant operation of TACAN) and pairing of Section 3.5 of Annex 10, Volume I, Radio Navigation Aids. In particular, the following note currently exists at the end of Table A:
108.0 MHz is not scheduled for assignment to ILS service. The associated DME operating channel No. 17X may be assigned for emergency use.
108.0 MHz is scheduled for assignment to VOR and VOT (Test VOR) service, but not for ILS service. The to 108.00 MHz associated DME operating channel No. 17X may in addition to operational use be assigned for emergency use.
2.2In order to bring attention to the use of 978 MHz by the UAT, the following modification is proposed:
108.0 MHz is not scheduled for assignment to ILS service. The associated DME operating channel No. 17X may be assigned for emergency use. The reply frequency of channel No. 17X (i.e., 978 MHz) is also utilized for the operation of the Universal Access Transceiver (UAT). Standards and Recommended Practices for UAT are found in Volume yy, Chapter xx.
Regions may choose to exempt 17X from operational use for operational assignments e.g. by reserving it for emergency use
or for utilizing the transponder reply frequency 978 MHz for the operation of the Universal Access Transceiver (UAT). Standards and Recommended Practices for UAT are found in Volume yy, Chapter xx.
3.0Proposed Change Number 2
3.1As shown below, channel planning criteria for the DME are referenced in Annex 10, Volume I, Chapter 3, but largely contained in Chapter 7 of that document.
Annex 10, Volume I, Radio Navigation Aids
CHAPTER 3. SPECIFICATIONS FOR RADIO NAVIGATION AIDS
3.5 Specification for UHF Distance Measuring Equipment
…
3.5.3.3 Channelling
…
3.5.3.3.4 Area channel assignment
3.5.3.3.4.1 In a particular area, the number of DME operating channels to be used shall be decided regionally.
Note.— Standards and Recommended Practices on the utilization of the DME frequency band 960-1 215 MHz are found in Volume V, Chapter 4.
Annex 10, Volume V, Aeronautical Radio Frequency Spectrum Utilization
CHAPTER 4. UTILIZATION OF FREQUENCIES ABOVE 30 MHz
4.3 Utilization in the band 960 – 1 215 MHz for DME
Note.— Guidance on the frequency planning of channels for DME systems is given in Volume I, Attachment C, Section 7.
Annex 10, Volume I, Radio Navigation Aids
ATTACHMENT C. INFORMATION AND MATERIAL FOR GUIDANCE
IN THE APPLICATION OF THE STANDARDS AND RECOMMENDED PRACTICES FOR ILS, VOR, PAR, 75 MHz MARKER BEACONS (EN-ROUTE), NDB AND DME and ICAO compliant use of TACAN
7. Material concerning DME
7.1 Guidance material concerning both DME/N and DME/P
…
7.1.7 Geographical separation criteria
…
7.1.8 Desired to undesired (D/U) signal ratios at the airborne receiver
…
7.1.9 Special considerations for DME Y and Z channel assignments
…
7.1.10Special considerations for DME W or Z channel assignments
…
7.1.11Special considerations for makingpulse spectrum measurements
…
7.1.12Special considerations for DME/P associated with ILS
…
3.2In order to address DME/UAT frequency planning criteria, the following addition to Annex 10, Volume I, Chapter 7 is proposed (Note: see Appendix A of this document for UAT Implementation Manual text):
7.1.13 Considerations for the Universal Access Transceiver (UAT)
7.1.13.1 Frequency planning criteria to ensure compatibility between DME and the UAT are contained in Chapter 7 of the Implementation Manual for the Universal Access Transceiver (UAT)
4.0Conclusion and Recommendation
4.1Frequency planning criteria to ensure compatible operation of DME and UAT have been developed and agreed by NSP and ACP. In order to bring attention to those criteria, proposed insertions for existing DME SARPs have been developed.
4.1It is recommended that the NSP endorse the inclusion of those insertions, and propose the revision of Annex 10 accordingly.
Appendix A
Implementation Manual for the Universal Access Transceiver (UAT)
7.UAT Frequency Planning Criteria
As previously discussed, the UAT frequency channel is centered at 978 MHz with a nominal bandwidth of 1 MHz. UAT/DME frequency channel planning criteria to support future high-level UAT environments will specify that the closest assignable DME Ground Station transmitting frequencies relative to the UAT frequency of 978 MHz are the first adjacent DME channels.
7.1 Use of 978 MHz for DME/TACAN in Low-Level UAT Environments
Test, simulation and analysis have shown that UAT and co-frequency DME can be operated on a compatible basis when both the number of DME stations in view to the UAT is limited, and the density of UAT transmitters is low. As 978 MHz is only sparsely used for DME on a worldwide basis, the limiting factor is generally UAT density.
Except in frequency congested areas (e.g. Europe) 978 MHz and adjacent frequencies are only sparsely used for DME on a worldwide basis, the limiting factor is generally UAT density.
Therefore, while low density UAT and 978 MHz DME are compatible, for States intending to implement UAT on a large scale, it is recommended that 978 MHz DMEs have their frequencies reassigned.whenever possiblean alternative frequency is coordinated for DME if necessary with adjacent states for states.
It should be noted however that in regions where the alternative to operational DME use of 978 MHz is for DME ramp test equipment this can still be supported, as the characteristics of the operational interaction scenario for UAT-to-ramp tester serves to preclude interference.
7.2 DME/TACAN to UAT Ground Station Siting Criteria
Extensive testing has indicated no operationally significant impact to DME/TACAN in a high density UAT environment when DME/TACANs are receiving on the first upper adjacent DME channel (979 MHz) to the UAT frequency (978 MHz). A similar result can be inferred for DME reception at the lower first adjacent channel of 977 MHz. Analysis of an example approach/landing scenario in Core Europe 2015 has shown that first adjacent channel DME operation is also compatible with an environment that includes a nearby UAT ground station broadcasting at a high duty factor.
Any limitations on the siting of UAT ground stations vis-à-vis DME/TACANs are likely to result from the effects of DME/TACAN transmissions on UAT performance. This question has been studied by examining UAT performance with a first upper adjacent channel DME/TACAN ground station co-located with a UAT ground station receiver at a high density airport. Air-air, ground-air, air-ground, and surface-surface performance were studied. The result of the combined analysis of these cases is a recommendation that a sufficient level of isolation be provided between a DME/TACAN transmit antenna and a UAT receiver on the surface. This could be supplied through either separation by distance or some other means, and the amount of isolation required depends on the parameters of the DME/TACAN and the design of the UAT receive system. For example, a separation distance of around 1.2 km between a 10 kW DME/TACAN (specify ERP, EIRP or Transmitter output power?) transmitting at 979 MHz and a three-sector UAT ground receive antenna at a high density airport in the Core Europe 2015 scenario provides more than adequate isolation for UAT air-ground operation. A similar separation distance would be sufficient for UAT and a DME/TACAN operating at a power level of 1 kW (specify ERP, EIRP or Transmitter output power?) or less on the first lower adjacent channel of 977 MHz; further analysis on a case by case basis is required for a DME/TACAN operating at a power level above 1 kW (specify ERP, EIRP or Transmitter output power?)on this frequency.