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MEETING REPORT Jim Cohen A
workshop on "Active Protection of Passive Radio Services:
towards a concerted strategy" was held in Cagliari,
Sardinia, Italy, on 28th and 29th October 2004.
The workshop was sponsored by the European Science Foundation,
with additional support from RadioNet.
The meeting addressed the threats to scientific use of passive
radio frequency bands from rapidly increasing use of the radio spectrum,
from growing levels of radio pollution, and from commercial pressures to
relax regulatory control. Deregulation
is used to increase competition in the market, but how can passive users
compete? The meeting
brought together for the first time the radio astronomical and remote
sensing communities, in a relaxed informal venue.
There were 26 delegates from 9 countries, who between them
represented 5 national and international space agencies, the meteorology
community, the aeronomy community, the geodetic community, and 6 major
radio astronomy observatories. The
meeting venue, the Hotel Panorama, was only 35 km from the site where
the Sardinia Radio Telescope (SRT) is under construction. Nichi D'Amico (INAF-OAC Director) welcomed participants and
gave a presentation on the SRT project.
The SRT will be a 64-m diameter dish with an active primary
mirror, enabling it to cover a very wide frequency range of 0.3-100.0
GHz, with fast switching between operating frequencies.
The
full workshop programme is given in the Appendix to this report.
The first day covered the scientific needs of the different
communities. Willem Baan
and Bernard Lazareff described major new radio astronomy facilities
under construction or planned for the twenty first century. These will have 100 times the sensitivity of current
instruments and will cover wide frequency bands in order to detect
spectral lines from distant galaxies that have been redshifted outside
the protected bands, because of the expansion of the Universe.
New techniques of interference mitigation are being developed to
enable successful observations to be made in these circumstances, as
described by Rob Millenaar. But
the need for globally coordinated VLBI observations and for single dish
surveys means that the protection of passive frequency bands will also
remain a top priority for the foreseeable future.
Hans
Richner and Guy Rochard described the frequency use for climate
monitoring, meteorology and environmental studies including monitoring
of greenhouse gases such as CO2, CH4, O3
and CH3Cl. The
work includes active and passive measurements from space, from the
ground and using radio sondes and other meteorological aids.
The developments in ultra-wide band (UWB) devices including those
for short range radar on cars have highlighted the need to make the
radio community aware of passive frequency uses and techniques, and to
make meteorologists more aware that the radio spectrum is not unlimited,
so that constructive dialogue can start.
We need to be ready to justify every single frequency allocation
and to explain what the true cost would be if the World Meteorological
Organization were to lose the use of different bands.
The UWB situation was discussed by Vincent Meens. Current studies specify assumed densities of devices, their location (indoor or outdoor) and level of activity, but in practice how can these parameters be controlled? Studies have raised the issue of apportionment of interference among different sources, which is being pursued within ITU-R, as described by Thomas vonDeak. The question of whether interference can be mitigated is being raised. However it is impossible to mitigate very low level interference either in passive sensing or radio astronomy. A passive sensor simply integrates the total power across the band, so if there is an interfering component this will result in wrong data being recorded and processed, and eventually in a wrong weather forecast. Robert Wolf explained the situation at 24 GHz, where car manufacturers want to use a frequency that breaks all the ITU rules, simply because a cheap chip is available right now. The expected interference to satellite sensors will affect measurements at many frequencies, since the 24-GHz measurements are used to calibrate other bands. Jerome
de la Noe described techniques for studying the middle atmosphere from
the ground using passive microwave radiometry to obtain vertical
profiles of atmospheric gases. The
Network for Detection of Stratospheric Change (NDSC) runs monitoring
stations that have no official status within the ITU, but which play an
important complementary role to satellite sensors, tracking time
evolution. Limb sounding
from space using the ODIN satellite at submm wavelengths was discussed
by Joachim Urban, while Dietrich Feist described stratospheric sounding
of water vapour from aircraft, and interference over certain regions.
Istvan
Fejes, a self-confessed cuckoo in the nest, described the use of global
navigation satellites for Earth science:
tectonics, Earth rotation and atmospheric sensing.
He reported on a GNSS interference programme carried out at the
Central European GPS Geodynamic Reference Network (CEGRN) sites.
The UN Office on Outer Space Affairs (NOOSA) is interested to set
up a global working group on Site quality, integrity and interference
monitoring. Among
many emerging issues, Titus Spoelstra spoke about powerline
communications, broad band multimedia from satellites and the concept of
interference temperature as a tool for squeezing more users into the
radio spectrum, while Ryszard Struzak described developments in
stratospheric radio using aircraft and balloon platforms to cover wide
service areas cheaply. The
scientific community needs observer status at the EC discussions and
elsewhere, to know what is coming.
The
second day covered political and structural issues, and the forward
look. Massimo Martinelli
explained the role of the ESF, its aims and its instruments, including
workshops such as this one. As
a recognized non-governmental body covering more countries than the EC,
the ESF might be able to help us in our negotiations at European level.
Klaus
Ruf described the development of the concept of passive radio services
within the ITU, and the protection afforded to the passive frequency
bands. However UWB is not a
service, and indications are that our protection will depend on our own
skills in defending our interests within TG1/8 and elsewhere.
Titus Spoelstra emphasised the need for all passive services to
present a coherent agreed position within the ITU, CEPT, national
administrations and the general public, and to improve our visibility to
all these groups. The
organization and role of IUCAF was explained by the Chairman, Wim van
Driel. ICSU in its recent
review recommended that IUCAF becomes truly interdisciplinary to take
care of all passive services. The
meeting was strongly in favour of adding lectures on remote sensing to
the second IUCAF Summer School in Spectrum Management, to be held in
June 2005. Edoardo Marelli,
Chairman of the SFCG, described the structure and objectives of SFCG.
Although passive sensing is only one aspect of SFGC activity, it
is one of the most important. Participation
of radio astronomers as observers has proved very useful and perhaps the
presence of other passive users could also be useful.
SFCG helped to broker the agreement on coordinating future cloud
radar missions at 94 GHz with radio astronomy operations. Forthcoming
WRC agenda items of interest to the passive services were introduced in
a series of talks by Jim Cohen, Manfred Otter and Bjorn Rommen, the
details of which can be found in their presentations.
The
heart of the workshop was the subsequent Open Discussion chaired by
Edoardo Marelli, which covered the following topics: 1.
Organizational Situation.
Much can be achieved by a pragmatic small steps approach. The need for personal representation of the two groups on
each others' committees was reiterated.
Good liaison will ensure that early alarms are raised. Better coordination and exchange of information can help us
all. It was agreed that an
internet-based forum (such as a wiki) would facilitate this.
Willem Baan and Ignazio Porceddu agreed to investigate the
possibilities for setting this up on the Astron or Cagliari web sites.
It was felt that the CRAF-IUCAF Summer School 2005 will be of
interest to the passive sensing community, and should include some
lectures on those issues. In
the longer term a more formal structural solution could come through
enlarging the mandate and constitution of IUCAF.
2.
Political Aspect.
The discussions were primarily concerned with influencing
European policy, since most participants were from European
organizations. We need to target the decision makers in frequency management
at national level, so they can support us better internationally.
We need to stress the economic value of keeping passive frequency
bands empty not just with qualitative arguments but by providing real
figures. We also need to
improve our high level contacts so that our case is known at political
level. One aim in Europe is
to get observer status for the ESF at the RSPG (Radio Spectrum Policy
Group) as a general (neutral) representative of the science community. Roberto
Ambrosini will investigate. 3.
Regulatory Situation. Within
Europe, very few of the 45 CEPT national authorities are sufficiently
aware of the need to protect passive services.
Also at EC level our needs are not understood.
We need to increase this awareness, to avoid the situation where
individual national administrations take (uniformed) unilateral actions
to our detriment. We need
to lobby for pre-launch tests of unwanted emissions from satellites, for
improved monitoring of frequency usage, and for respect of the ITU
rules. In the long term we need a definition of the ground-based
passive atmospheric sensors as a service, perhaps via meteorological
aids. 4.
WRC-07 Specific Issues.
We already have good coordination and common positions on
unwanted emission and 1.4 GHz. For
the WRC-10 agenda we need good coordination on the agenda item for
frequencies above 275 GHz, to ensure that we have a compelling case
before the WRC-10 agenda is decided at WRC-07.
It was decided that our 3 contact points for the three areas
should be Wim van Driel (radio), Guy Rochard (passive sensing from
satellites) and Jerome de la Noe (passive sensing from the ground).
The contact persons are to gather data, perhaps via the new wiki,
and we will try to make a workshop to merge the 3 cases.
In the long term we need to develop a position on the question of
regulation of optical and infrared frequencies.
Summary
Action
Items. (a)
Establish an internet forum
(wiki) - Willem Baan and Ignazio Porceddu; (b)
Try to get ESF observer status on RSPG - Roberto Ambrosini to
investigate; (c)
Establish contact group on
above 275 GHz issues – Wim van Driel, Guy Rochard and Jerome de la Noe
to gather information from their respective communities; (d)
Meeting report - action Jim Cohen; (e)
Update presentations and send them to Ignazio Porceddu – action
all speakers; (f)
publish the report and
presentations on the web - action Leonardo Mureddu;
(g)
produce policy statement
suitable to use in contacts with officials, administrations, the EC,
etc. - action on the
organizing committee; (h)
Include passive sensing
lectures in the 2005 Summer School - action IUCAF and CRAF. (i) Organize
future workshop, probably in 2006, to focus on >275 GHz issues –
action all. |