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Satellite Coordination

Satellite Coordination. R. J. Cohen. 13th June 2002. Jodrell Bank Observatory University of Manchester. Outline of Presentation What is Coordination? Regulatory Requirements Satellite Downlinks MES Uplinks Paper Satellites WRC-03 Issues. What is Coordination?

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Satellite Coordination

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  1. Satellite Coordination R. J. Cohen 13th June 2002 Jodrell Bank Observatory University of Manchester

  2. Outline of Presentation • What is Coordination? • Regulatory Requirements • Satellite Downlinks • MES Uplinks • Paper Satellites • WRC-03 Issues

  3. What is Coordination? Before an administration allows an operator to commence operation of a new system, other administrations likely to be affected must be informed and agree to technical and operational parameters, perhaps with conditions. Once coordination is completed the system can be registered with the IFRB on the Master International Frequency Register. Systems so registered acquire protected status (even if not implemented) and incoming systems must coordinate with them. Coordination is critical for satellite systems.

  4. CHAPTER III of RR Coordination, notification and recording of frequency assignments and Plan modifications Article 7 Application of the procedures Article 8 Status of frequency assignments recorded in the Master International Frequency Register Article 9 Procedure for effecting coordination with or obtaining agreement of other administrations Article 11 Notification and recording of frequency assignments Article 12 Seasonal planning of the HF bands allocated to the broadcasting service between 5900 kHZ and 26 100 kHz

  5. CHAPTER III of RR (ctd.) Article 13 Instructions to the Bureau Section I - Assistance to administrations by the Bureau Section II – Maintenance of the Master Register and of World Plans by the Bureau Section III – Maintenance of the Rules of Procedure by the Bureau Section IV – Board documents Article 14 Procedure for the review of a finding or other decision of the Bureau However, if the administration which requested the review disagrees with the Board’s decision it may raise the matter at a world radiocommunication conference.

  6. Article 9 Procedure for effecting coordination with or obtaining agreement of other administrations Section I – Advance publication of information on satellite networks or satellite systems not earlier than five years and preferably not later than two years before the planned date of bringing into use characteristics to be provided are listed in Appendix 4 Section II – Procedure for effecting coordination administrations have four months to respond

  7. Article 9 ctd. Footnote 9.50.1 In the absence of specific provisions in these Regulations relating to the evaluation of interference, the calculation methods and the criteria should be based on the relevant ITU-R Recommendations agreed by the administrations concerned. In the event of disagreement on a Recommendation or in the absence of such a Recommendation, the methods and criteria shall be agreed between the administrations concerned. Such agreements shall be concluded without prejudice to other administrations. The administrations may agree to use Rec. RA.769-1

  8. Appendix 4 Consolidated list and table of characteristics for use in the application of the procedures of Chapter III Annex 1A: List of characteristics of stations in the terrestrial services Annex 1B: Table of characteristics to be submitted for stations in the terrestrial services Annex 2A: Characteristics of satellite networks or earth or radio astronomy stations Annex 2B: Table of characteristics to be submitted for space and radio astronomy services

  9. Appendix 4 ctd. Annex 2A: A.17 Compliance with aggregate power flux-density limits (a) NGSO satellites of RNSS in band 5010-5030 MHz, aggregate pfd into the bands 5030-5150 MHz and 4990-5000 MHz (5.553B) (b) NGSO FSS satellites in band 41.5-42.5 GHz into the band 42.5-43.5 GHz for >2% of time (5.551G) (c) RNSS in band 1164-1215 MHz (d) NGSO FSS satellites in band 15.34-15.63 GHz aggregate pfd into band 15.35-15.4 GHz (5.511A)

  10. Appendix 5 • Identification of administrations with which coordination is to be effected of agreement sought under the provisions of Article 9 • Table 5-1 Technical conditions for coordination • Lists thresholds or conditions (triggers), such as • bandwidth overlap • orbital position relative to existing system • epfd into certain frequency band • coordination area of earth station covers territory of another administration

  11. Appendix 7 Methods for the determination of the coordination area around an earth station in frequency bands between 100 MHz and 105 GHz 96 pages: includes antenna gain, propagation model

  12. Article 21 Terrestrial and space services sharing frequency bands above 1 GHz Section V – Limits of power flux-density from space stations (Table 21-4). Higher pdf is allowed at higher elevation angles! Article 22 Space services Section II - Control of interference to geostationary-satellite systems (Tables 22-1 to 22-4 give epfd limits) Section V – Radio astronomy in the shielded zone of the Moon

  13. Reaching an Agreement • Interference issues may be resolved through e.g. • Technical conditions: • limiting transmitter power or power-flux density • limiting power in adjacent-band channels • limiting satellite coverage (e.g. beam shaping) • adding filters to transmitters • Operational conditions: • frequency planning of satellite network • restricting pointing directions of radio telescope • time sharing / coordination e.g. cloud radar 94 GHz

  14. Comments on Coordination • In general, coordination discussions start with pessimistic assumptiions about interference generation and reception, and gradually refine the assumptions based on actual parameters rather than envelope or generic parameters. • Radio astronomers need to defend each of their requirements robustly in such a discussion: • Do Rec.RA.769-1 assumptions apply to your station? (Tsys, integration time, resolution bandwidth, 0dBi) • Do other mitigation factors apply? (digitization loss, polarization discrimination, site shielding, etc.) • The process is one-way: no more protection than 769!

  15. PFD and EPFD Aggregate power flux density W m-2 Hz-1 from a constellation of satellites is averaged over all directions of arrival equally (0dBi). Equivalent power flux density (Article 22.5C1) from a constellation of satellites is a weighted average taking into account the off-axis discrimination of the transmitter and a reference antenna, each assumed to be pointing in its nominal direction. Epfd was developed for GSO (BSS and FSS) and NGSO sharing studies. It is now the favoured approach for radio telescopes, using a Monte Carlo method to simulate a range of observing situations.

  16. Monte Carlo Simulations The philosophy behind the Monte Carlo approach is that worst-case situations are rare. Most of the time the sharing requirements are relaxed. Hence this approach is now used for MES, AMSS, unwanted emissions, … (any moving interferer) A great many input parameters need to be agreed by all parties (emission masks, antenna patterns etc.); some parameters are commercially sensitive. Software to calculate epfd is expensive. Nobody has provided experimental data to confirm or deny the value of the Monte Carlo approach to sharing with radio astronomy.

  17. Res.125 (WRC-97) • Frequency sharing in the bands 1610.6-1613.8 MHz and 1660-1660.5 MHz between the Mobile-satellite service and the radio astronomy service • Rec. ITU-R M.1316 may be used to facilite coordination between mobile earth stations and radio astronomy stations in these bands • A future competent conference should evaluate frequency sharing in these bands based upon the experience gained with the used of M.1316 • invites ITU-R to submit a report to that future conference on the effectiveness of using M.1316 and other recommendations aimed at facilitating sharing

  18. Paper Satellites • Until the 1980s most satellite systems filed with ITU had been designed and would fly • In 1988 Tongasat began applying for GSO slots that it could not use in the foreseeable future (www.mendosa.com/tongasat.html) • Others got the same idea to stake claims cheaply • Nowadays there is massive overfiling – each filed system must be processed by ITU and coordinated by administrations • ITU backlog is increasing despite attempts to reform the process (e.g. “due diligence”)

  19. WRC-03 Issues • Res. 128 Protection of the radio astronomy service in the 42.5-43.5 GHz band • Provisional pfd limits of 5.551G to be reviewed • Mitigation techniques to be identified by ITU-R (including measures that may be implemented to reduce the susceptibility of RAS to interference) • Administrations urged to protect RAS against systems coordinated before 5.551G. • Res. 604 Studies on compatibility between RNSS in band 5010-5030 MHz and RAS in band 4990-5000 MHz • Review provisional pfd limits of 5.443B • Calculated aggregate pfd to be provided when filing

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