Satellite%20Coordination

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

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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.
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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
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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 Boards decision it may raise
the matter at a world radiocommunication
conference.
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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
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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
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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
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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 gt2 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)
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• 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

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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
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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
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• 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

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• 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!

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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.
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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.
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• 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

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• 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)

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• 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