Transcript No Slide Title

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?
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.
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
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.
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
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
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
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 49905000 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)
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
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
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 geostationarysatellite systems (Tables 22-1 to 22-4 give epfd limits)
Section V – Radio astronomy in the shielded zone of the
Moon
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
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!
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.
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.
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
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”)
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