CRAF Newsletter 2000/2
CRAF Newsletter 2000/2
September 2000
The European Science Foundation is an association of its 67 member
research councils and academies in 23 countries. The ESF brings
European scientists together to work on topics of common concern, to
co-ordinate the use of expensive facilities, and to discover and
define new endeavors that will benefit from a co-operative approach
The scientific work sponsored by ESF includes basic research in
the natural sciences, the medical and biosciences, the humanities and
the social sciences.
The ESF links scholarship and research
supported by its members and adds value by cooperation across national
frontiers. Through its function as coordinator, and also by holding
workshops and conferences and by enabling researchers to visit and
study in laboratories throughout Europe, the ESF works for the
advancement of European science.
On behalf of European radio astronomers, the ESF
Committee on Radio Astronomy Frequencies, CRAF, coordinates activities
to keep the frequency bands used by radio astronomers free from interference.
Contents
Radio astronomers made major gains at WRC-2000. The
success was due largely to international coordination of the radio
astronomy position over several years prior to the conference.
The results are detailed in Section 3 of this Newsletter, but some
highlights will be mentioned here.
(i) Firstly under agenda item 1.16, new allocations above 71 GHz,
guaranteed access was secured to nearly all of the spectrum that is
observable from the ground through the atmospheric windows, in the
range 71-275 GHz. Radio astronomers have operated in this part of the
spectrum for many years, and it is good news for us to have official
primary status in the bands after so long.
(ii) Secondly under 1.2, unwanted emissions, limits were placed
on unwanted emissions from satellites. The actual limits fall
short of what is needed to guarantee protection for radio astronomy
in all frequency bands, particularly from high-powered transmitters.
However the possibility has been left open for
WRC-03 to set tighter regulatory limits in specific bands for specific
satellite services (either for spurious emissions or out-of-band
emissions).
(iii) Thirdly, concerning new allocations for satellite downlinks
(items 1.4, 1.14 and 1.15), radio astronomy had mixed
fortunes. Unfortunately for us
WRC-2000 made further allocations of satellite downlinks very
close to radio astronomy bands. However the affected
radio astronomy bands were given strong regulatory protection
from the relevant satellite downlinks via new footnotes
which state that the satellite systems shall protect
radio astronomy observatories to specified power flux-density levels
calculated by radio astronomers (Rec. ITU-R RA.769-1). I personally am very
glad to see some of our protection criteria appearing in the Radio Regulations
for the first time, but I wish the
circumstances were different.
Much hard work now lies ahead of us to prepare for WRC-03, which
contains twice as many agenda items as did WRC-2000. Items of most concern
to radio astronomy are listed in Section 4 of this Newsletter.
R. J. Cohen
Jodrell Bank Observatory
The 30th CRAF meeting was held on 11 August 2000 at the University of Manchester, during
the 24th General Assembly of the International Astronomical Union, IAU. The main items
discussed concerned an evaluation of the results of WRC-2000, the planning of work for WRC-03,
the update of the CRAF terms-of-reference and the coordination of aeronautical earth stations
at 1.6 GHz.
World Radiocommunication Conference 2000, WRC-2000:
the meeting reviewed the results of the WRC-2000 and noted their impact on radio
astronomy, i.e. the new allocations in the frequency range 71-275 GHz. The meeting made a
preliminary evaluation of CRAF's participation and preparation for WRC-2000 with the
perspective to future WRCs. The key point is that CRAF should critically evaluate its
activities and pro-actively seek any improvement.
Preparation of WRC-03:
CRAF identified the agenda items of the WRC-2003 which are relevant for
radio astronomy. CRAF manpower will be linked with each agenda item to improve the
preparation for this WRC. Within the CEPT, it is not yet certain which working group or project
team will address each agenda item, since the key CEPT groups have not met yet.
CRAF Terms-of-Reference:
a preliminary draft version of the updated CRAF Terms-of-Reference was presented to the
meeting. In autumn 2000 the final draft will be submitted to the European
Science Foundation.
Aeronautical Earth Station coordination:
Following an action item from SE28, Inmarsat and CRAF studied the coordination of AESs and
radio astronomy stations in the band 1660-1670 MHz. The conclusions from this study are used
in the new ETSI standard for AESs. SE8 informed CEPT/ERC WG SE which wrote a liaison statement
on the issue to ETSI TC-SES. Following correspondence between TC-SES and WG SE a liaison
statement from WG SE was sent to TC SES suggesting preliminary standard values for the band
1610.6-1613.8 MHz. WG SE sent CRAF a copy with a request for comments. CRAF will react before
the next WG SE meeting which is held early October 2000. (see also section
6 of this Newsletter.)
ESA/IAU initiative:
The International Astronomical Union, IAU, asked CRAF for participation on scientific and
technical criteria on protective criteria for radio astronomy in the context of an ESA/IAU
initiative. The IAU supports work on protective measures for radio astronomy but has no clear
action plan for this. CRAF agreed to support the initiative wherever possible and formed a
little 'think-tank' to develop ideas supporting the initiative.
T.A.Th.Spoelstra
Dwingeloo Observatory
The WRC-2000 agenda (Istanbul, 8 May - 2 June, 2000) included
several items which where of great importance
for radio astronomy. The results on these issues were as follows:
item 1.2 - spurious emissions:
The Appendix S3 to the ITU-R Radio Regulations and Recommendation 66 were revised and
to complete the work on Recommendation 66, an agenda item dealing with unwanted emissions
for WRC-03 was proposed. This will allow the results of the work on boundary between
spurious and
out-of-band emissions to be transferred to the Radio Regulations
and the necessary regulatory measures to protect passive services to be defined.
Appendix S3 (spurious emissions) was revised in accordance with the CEPT positions except for
the splitting of the space services by categories. Recommendation 66 was amended to take into
account the progress made on space services; it now includes a noting in line with the
conclusion of TG 1-5 on out-of-band limits (no inclusion of out-of-band limits in the Radio
Regulations before WRC-2000). To Recommendation 66 a new recommends 7 was added which reads:
" Study the matter of reference bandwidth in the space services and the option of modifying
Appendix S3, Table II by separately identifying individual space services."
item 1.4 - high density fixed service and fixed-satellite service: this agenda item dealt
with a number of resolutions from WRC-97 and a number of frequency bands. The most important for
radio astronomy are Resolution 128 and the 42.5-43.5 GHz band, allocated to radio
astronomy, threatened by an allocation to the Fixed-Satellite Service (space-to-
Earth) in the band 41.5-42.5 GHz in ITU-Regions 2 and 3;
the WRC-2000 allocated the whole frequency range 40.5-42.5 GHz to the Fixed-Satellite Service
(space-to-Earth). With the aim of protecting radio astronomy, the band 42-42.5 GHz has
been allocated to GSO systems in the Broadcasting-Satellite and Fixed-Satellite Services. This
allocation is given as a guard band to protect radio astronomy in the band 42.5-43.5 GHz. In
addition footnote S5.551G is given with additional criteria to
protect radio astronomy in this band. Following the revised Resolution 128, the WRC-03
will reconsider the criteria given in this footnote.
item 1.14 - feasibility of MSS feeder links at 15.43 - 15.63 GHz in accordance with
Resolution 123:
For the band 15.43-15.63 GHz, WRC-2000 agreed to limit the use to systems
for which advance publication was received prior to 2 June 2000. WRC-2000
also modified footnote
S5.511A which includes provisional power flux density limits to
protect the radio astronomy service in the band 15.3-15.4 GHz. which now states that this band
is also allocated to the fixed-satellite service (space-to-Earth) on a primary basis.
item 1.15.1 - new allocations to the Radionavigation-Satellite Service required to
support developments in the range from 1 to 6 GHz:
The WRC agreed new allocations for the Radionavigation-Satellite Service in the following
frequency bands: 1215 - 1300 MHz, 1559 - 1610 MHz and 5010 - 5030 MHz for the (space-to-Earth)
and (space-to-space) directions, and 1300 - 1350 MHz and 5000 - 5010 MHz for the (Earth-to-space)
direction. This allocation was made to satisfy the requirements of the European GALILEO
system which is developed as a civil RNSS facility.
To protect the radio astronomy services in the band, footnote S5.443B has been added
which states inter alia that in order not to cause harmful interference to the radio astronomy
service in the band 4990 - 5000 MHz, the aggregate power flux-density produced in the
4990 - 5000 MHz band by all the space stations within any RNSS
(space-to-Earth) system operating in the 5010 - 5030 MHz band shall not exceed the provisional
value of -171 dB(W/m2) in a 10 MHz band at any radio astronomy observatory site
for more than 2% of the time.
item 1.16 - allocation of frequency bands above 71 GHz to the EES (passive) and
RAS, taking into account Resolution 723:
WRC-2000 has allocated to science services (i.e. radio astronomy, remote sensing and space research)
all the frequencies between 71 and 275 GHz in such a way that the allocations are optimized
for the propagation conditions through the terrestrial atmosphere. For radio astronomy this
means that the frequency windows for which the atmosphere is transparent have formally
been allocated to radio astronomy, apart from their very edges.
The WRC also moved most of the frequencies allocated to satellite downlinks within the
71-275 GHz range to frequencies not used for scientific research. Since no
satellites yet operate at these high frequencies, no equipment needs to be
altered.
In addition the footnote regulating the scientific interest in radio frequencies between
275 GHz and 1 THz has also been adjusted in such a way that those frequency windows
for which the atmosphere is transparent have been noted for use by radio astronomy and
remote sensing applications. The issue of formal allocations between 275 and 1000 GHz
is on
the Agenda of the Conference that is now planned for 2006.
Other agenda items of which the results require radio astronomy attention are:
item 1.5 - consider regulatory provisions and possible additional frequency allocations for
services using HAPs taking into account the results of Resolution 122:
Resolution 122 was modified: the time frame of the 47 GHz sharing studies was extended
and this topic will be resolved by WRC-03. Also the ITU-R requested a feasibility study of additional spectrum
for HAPs within the fixed service in the 18 - 32GHz range with a focus on 27.5 - 28.35 GHz and
31 - 31.3 GHz bands. The latter band is adjacent to the radio astronomy band 31.3 - 31.8 GHz.
item 1.6.1 - review the spectrum requirements for the operation of terrestrial IMT-2000 with
the view to identify future expansion bands and adjustments to the Table of Allocations:
WRC-2000 agreed on several IMT-2000 assignments in addition to the already identified
bands 1885-2025 MHz and 2110-2200 MHz. One of them is the 2670 - 2690 MHz
band for which radio astronomy has a secondary allocation, adjacent to
the primary passive radio astronomy band 2690 - 2700 MHz.
item 1.9 - take into account the results of ITU-R studies in evaluating the feasibility of an
allocation in the space-to-Earth direction to the MSS in a portion of the 1559 - 1567 MHz
frequency range, in response to Resolutions 213 and 220:
WRC-2000 adopted the resolutions COM5/29 and COM5/30, which would call for
ITU studies of the feasibility of allocating this band to MSS, respectively for the downlink
band (with an emphasis on the band 1518-1525 MHz) and the uplink band (with an emphasis on
the band 1683-1690 MHz). The next WRC should then deal with MSS allocations not only in this
band but also other bands, which have not been negated such as 1559-1567 MHz. Furthermore,
Resolutions 220 and 213 were suppressed.
item 1.10 - to consider the results of ITU-R studies in accordance with Resolution 218
(Use of the bands 1525 - 1559 MHz and 1626.5 - 1660.5 MHz by the MSS):
The generic allocation for MSS has been preserved with unchanged S5.353A and S5.357A. The
new Resolution COM5/22 answers some concerns of the civil aviation and GMDSS communities
while not prejudging the outcome of studies on inter-system prioritization and pre-emption.
item 1.11 - consider constraints on existing allocations and to consider additional allocations
on a worldwide basis for the non-GSO/MSS below 1 GHz, taking into account Resolutions
214 (Rev WRC-97) and 219:
WRC-2000 did not adopt further allocations to MSS below 1 GHz. As part of the compromise,
such additional allocations will be re-examined in WRC-2003 under agenda item 1.20, in
accordance with Resolution 214.
item 1.13 - on the basis of the results of the studies in accordance with Resolution 130
on the "Use of NGSO systems in the FSS in certain frequency bands":
WRC-2000 adopted power fluxed density (pfd) limits and equivalent power flux density (epfd)
limits for inclusion in Articles S21 and S22 of the ITU-R Radio Regulations.
item 1.17 - to consider possible worldwide allocations for the EES (passive) and SR (passive)
services in the band 18.6 - 18.8 GHz taking into account the results of the ITU-R studies:
WRC-2000 upgraded the allocation of the band 18.6-18.8 GHz from secondary to primary status
on a world-wide basis.
The WRC-2000 adopted 35 agenda items for conclusion at the WRC-03. Those particularly
relevant for radio astronomy are:
agenda item 1.8: to consider issues related to unwanted emissions:
agenda item 1.8.1: consideration of the results of studies regarding the boundary
between spurious and out-of-band emissions, with a view to including the boundary in Appendix
S3;
agenda item 1.8.2: consideration of the results of studies, and proposal of any
regulatory measures regarding the protection of passive services from unwanted emissions,
in particular from space service transmissions, in response to recommends 5 and 6 of
Recommendation 66 (Rev.WRC-2000);
agenda item 1.11: to consider possible extension of the allocation to the
mobile-satellite service (Earth-to-space) on a secondary basis in the band
14-14.5 GHz to permit operation of the aeronautical mobile-satellite service as
stipulated in Resolution 216 (Rev.WRC-2000);
agenda item 1.13: to consider regulatory provisions and possible identification of
existing frequency allocations for services which may be used by high altitude platform
stations, taking into account No. S5.543A and the results of the ITU-R studies conducted
in accordance with Resolutions 122 (Rev.WRC-2000) and 734 (WRC-2000);
agenda item 1.15: to review the results of studies concerning the
radionavigation-satellite service in accordance with Resolutions 604 (WRC-2000),
605 (WRC-2000) and 606 (WRC-2000);
agenda item 1.16: to consider allocations on a worldwide basis for feeder links in
bands around 1.4 GHz to the non-GSO MSS with service links operating below 1 GHz, taking
into account the results of ITU-R studies conducted in response to Resolution 127
(Rev.WRC-2000), provided that due recognition is given to the passive services,
taking into account No. S5.340;
agenda item 1.20: to consider additional allocations on a worldwide basis for the
non-GSO MSS with service links operating below 1 GHz, in accordance with Resolution 214
(Rev.WRC-2000);
agenda item 1.32: to consider technical and regulatory provisions concerning the band
37.5-43.5 GHz, in accordance with Resolutions 128 (Rev.WRC-2000) and 84
(WRC-2000);
In addition, CRAF is monitoring the developments on:
agenda item 1.31: to consider the additional allocations to the mobile-satellite service
in the 1-3 GHz band, in accordance with Resolutions 226 (WRC-2000) and
227 (WRC-2000);
agenda item 1.33: to review and revise technical, operational and regulatory provisions,
including provisional limits in relation to the operation of high altitude platform stations
within IMT-2000 in the bands referred to in No. S5.388A, in response to Resolution
221 (WRC-2000);
In its meeting of 12-13 July 1999, the project team SE28 of the ERC Working Group SE identified an
action item on CRAF and Inmarsat to study the protection of the Radio Astronomy Service in the
band 1660-1670 MHz from harmful interference from AESs operating the
band 1626.5-1660.5 MHz.
The study was carried out in the period September to December 1999 and CRAF and Inmarsat presented the
results to the meeting of SE28 on January 27-28, 2000. During the study, both
CRAF and Inmarsat informed each other in detail on the various operational and technical
parameters relevant for the study. CRAF and Inmarsat evaluated this information and adopted the
parameters on which the final results were based.
The results of this work have been liaised with WG SE and ETSI/TC-SES. CRAF
notes that the liaison statement from WG SE to ETSI/TC-SES contained the
text "In the band 1660-1670 MHz, CRAF and Inmarsat have agreed unwanted emission values..."
and "... WG SE does not wish to undermine the agreement between
CRAF and Inmarsat and is therefore accepting the proposed limits".
This wording gave rise to the assumption that an agreement exists between CRAF and
Inmarsat, similar to the agreements between the ESF and Iridium
LLC. To clear the situation, CRAF declares that no agreement between CRAF and Inmarsat
exists in the sense of a written and signed document and that the wording of the liaison statement
from SE28 to ETSI/TC-SES reflects the situation correctly.
The reason that no formal agreement exists between CRAF and Inmarsat is that
experience of the negotiations and the agreements with Iridium LLC taught CRAF that
agreements between a scientific and non-scientific entity are not appropriate, because the
characteristics of the two entities are too different.
CRAF considers that coordination between two radiocommunication services should be
dealt with by the proper national regulatory authorities, in view of the legal implications.
For additional clarification: CRAF as a committee of the European Science Foundation does not have the
legal mandate to sign a legally binding agreement with another private party. Only the
European Science Foundation has this authority which it may apply on behalf of CRAF whenever
necessary.
T.A.Th.Spoelstra
Dwingeloo Observatory
6.1. The issue
The European Telecommunication Standardization Institute, ETSI, requested CEPT project team
SE28 to study the power output levels for the development of a European Norm for
Aeronautical Earth Stations, AESs. The levels will be included in the draft norm, currently noted as
DEN/SES-00023 v.1.1.5, which must not be exceeded for
protection of radio astronomy in the band 1610.6-1613.8 MHz.
SE28 studied the frequency band 1610.6-1613.8 MHz and, after completion of the study, sent the
results in a liaison statement to ETSI/TC-SES.
6.2. SE28 studies
During the SE28 work process, Motorola proposed a power level for unwanted emissions in the band
1610.6-1613.8 MHz for the Iridium system of -80 dB(W/MHz) measured at antenna input or, in terms of
EIRP, -75 dB(W/MHz). The Motorola proposal was extensively discussed in SE28. In conclusion,
SE28 sent in April 1999 a liaison statement to ETSI/TC-SES proposing this value. This liaison
statement includes CRAFs concern based on the fact that the study leading to this value contained
many uncertainties. CRAF asked Motorola repeatedly, during the SE28 studies, to provide necessary
background and clarification, which were not provided to the satisfaction of CRAF and
therefore CRAF considered that the study was not complete. CRAF also noted that in the USA, Motorola
proposed a value of -90 dB(W/MHz) instead of the mentioned -80 dB(W/MHz): Motorola could not
explain this difference either.
Following the liaison statement from ETSI/TC-SES to SE28 of June 24th, 1999,
CRAF and Inmarsat studied the transmitter power output level for AESs in the
band 1660.0-1670 MHz. The results were liaised back to ETSI/TC-SES.
The liaison statement of WG SE to ETSI/TC-SES was followed by the request
of ETSI/TC-SES to speed up matters to complete the work for 1610.6-1613.8 MHz and in response
to this WG SE sent a liaison statement to ETSI/TC-SES proposing a
provisional value of -65 dBW per 20 kHz. It was also stated that this value is subject to change
when further studies within WG SE so require.
6.3 ETSI/TC-SES and CRAF
As noted, ETSI/TC-SES asked the CEPT WG SE project team SE28 for transmitter power output
levels for AESs. The results of the work of SE28 were liaised to ETSI. CRAF
worked within SE28 on the subject but has not the mandate to participate in the public enquiry
on the related draft EN/SES-00023 V1.1.5 because CRAF is not an ETSI member.
CRAF cooperates intensively with European national administrations and the CEPT and depends
fully on their position within ETSI concerning the protection of radio astronomy.
T.A.Th.Spoelstra
Dwingeloo Observatory
AES = Aeronautical Earth Station
BSS = Broadcasting-Satellite Service
CEPT = Conference of European Post and Telecommunication administrations
COM = Commission
CRAF = Committee on Radio Astronomy Frequencies (ESF)
DEN = Draft European Norm (ETSI)
EESS = Earth Exploration-Satellite Service
EIRP = Effective Isotropic Radiated Power
ERC = European Radiocommunications Committee (CEPT)
ESF = European Science Foundation
ETSI = European Telecommunication Standardization Institute
FSS = Fixe-Satellite Service
GSO = Geostationary Satellite Orbit
HAPS = High Altitude Platform Station
IMT-2000 = International Mobile Telecommunication System
ITU = International Telecommunication Union
ITU-R = International Telecommunication Union - Radiocommunication Sector
MSS = Mobile-Satellite Service
SE = Spectrum Engineering (CEPT)
TC-SES = Technical Committee on Satellite Earth Stations and Systems (ETSI)
MSS = Mobile-Satellite Service
NGSO = non-GSO
SR = Space Research Service
WG = Working Group
WRC = World Radiocommunication Conference (ITU-R)
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Last modified: February 26, 2001