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EXECUTIVE SUMMARY
The passive, receive‐only Radio Astronomy Service (RAS) and the Earth Exploration‐Satellite Service
(EESS) provide otherwise impossible scientific observations of the Universe and Earth through the use of
advanced receiver technology with extreme sensitivity and the employment of complex noise reduction
algorithms. Even with such technology, RAS and EESS are quite adversely affected by what most active
services would consider low noise levels.
The emissions that radio astronomers receive are extremely weak—a radio telescope receives only
about one‐billionth of one‐billionth of a watt (10‐18 W) from a typical cosmic object. Similarly, remote‐
sensing scientists observe the noise floor itself and extremely weak variations therein. Their
observations are also very vulnerable to interference from man‐made transmissions. Interference from
in‐band emissions, spurious, and out‐of‐band emissions from licensed and unlicensed users of
neighboring bands, and emissions that produce harmonic signals in the RAS and EESS bands, is quite
harmful to RAS and EESS observations. Even weak, distant in‐band man‐made emissions can preclude
use. Moving to other bands is not always an option: in order to fulfill their scientific missions, in many
cases radio astronomers and remote‐sensing scientists must observe at the specific frequencies
characteristic of elements or molecules that are established by the laws of physics and chemistry.
To ensure their ability to use the radio spectrum for scientific purposes, scientists must be party to the
discussion in the lead‐up to the World Radiocommunication Conference (WRC), which will next be held
in January and February 2012 in Geneva, Switzerland. By request of the National Science Foundation
and the National Aeronautics and Space Administration, a committee of the U.S. National Research
Council was convened to provide guidance to U.S. spectrum managers and policymakers as they prepare
for the WRC in order to protect the scientific exploration of the Earth and Universe using the radio
spectrum (see Appendix for the committee’s Statement of Task). While the resulting document is
targeted at U.S. agencies, representatives of foreign governments and foreign scientific users will find its
contents useful as they plan their own WRC positions.
This report identifies and discusses only those Agenda Items with relevance and potential impact to
radio astronomers and Earth remote sensing researchers. It does not discuss the numerous other
Agenda items.
The committee’s consensus opinion on the potential impact and relevance of certain Agenda Items at
issue at the WRC in 2012 are given in the main body of this report. The committee’s conclusions and
recommendations to Administrations preparing for WRC are listed in Table ES.1.
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Table ES.1 WRC‐12 Agenda Items of relevance and potential impact to RAS and EESS, and the
committee’s associated conclusions and recommendations given in the report, listed by Agenda Item.1
WRC‐12 Text of Agenda Item
Agenda Conclusion / Recommendation
Item
1.3 “to consider spectrum requirements and possible regulatory actions, including allocations,
in order to support the safe operation of unmanned aircraft systems (UAS), based on the
results of ITU R studies, in accordance with Resolution 421 (WRC 07);”
Recommendation: Transmissions in support of unmanned aircraft in the 5030‐5150 MHz
band should have sufficiently low level of unwanted emissions to avoid interference in the
adjacent RAS bands in accord with Recommendation ITU‐R RA.769.
1.4 “to consider, based on the results of ITU R studies, any further regulatory measures to
facilitate introduction of new aeronautical mobile (R) service (AM(R)S) systems in the bands
112‐117.975 MHz, 960‐1 164 MHz and 5 000‐5 030 MHz in accordance with Resolutions 413
(Rev.WRC 07), 417 (WRC 07) and 420 (WRC 07);”
Recommendation: Transmitters providing surface applications at airports in the 5000‐5030
MHz band should have sufficient suppression of out of band emissions to avoid interference
in the adjacent 5 GHz RAS band in accord with Recommendation ITU‐R RA.769.
1.6 “to review No. 5.565 of the Radio Regulations in order to update the spectrum use by the
passive services between 275 GHz and 3 000 GHz, in accordance with Resolution 950
(Rev.WRC 07), and to consider possible procedures for free‐space optical‐links, taking into
account the results of ITU R studies, in accordance with Resolution 955 (WRC 07);”
Recommendation: Administrations are urged to protect the bands given in Tables 1.6‐1 and
1.6‐3 from harmful interference for use by the RAS and EESS, respectively.
1.7 “to consider the results of ITU R studies in accordance with Resolution 222 (Rev.WRC 07) in
order to ensure long‐term spectrum availability and access to spectrum necessary to meet
requirements for the aeronautical mobile‐satellite (R) service, and to take appropriate
action on this subject, while retaining unchanged the generic allocation to the mobile‐
satellite service in the bands 1 525 1 559 MHz and 1 626.5‐1 660.5 MHz;”
Recommendation: Aeronautical mobile‐satellite (R) service transmissions in the overlapping
and adjacent bands should have out‐of band emissions below ‐237 dBW/(m2Hz) at
registered RAS sites, in accordance with Recommendation ITU‐R RA.769 for spectroscopic
observations.
1.8 “to consider the progress of ITU R studies concerning the technical and regulatory issues
1
From the International Telecommunications Union‐Radiocommunication Sector web site, as given at URL
http://www.itu.int/ITU‐R/index.asp?category=study‐groups&rlink=rcpm‐wrc‐12‐studies&lang=en, accessed July
28, 2010.
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relative to the fixed service in the bands between 71 GHz and 238 GHz, taking into account
Resolutions 731 (WRC 2000) and 732 (WRC 2000);”
Recommendation: Administrations are urged to protect the passive services from harmful
interference in 71‐238 GHz. Per Tables 1.8‐1 and 1.8‐2, this band is extremely important for
a wide range of scientific problems, both for RAS and EESS.
1.11 “to consider a primary allocation to the space research service (Earth‐to‐space) within the
band 22.55‐23.15 GHz, taking into account the results of ITU R studies, in accordance with
Resolution 753 (WRC 07);”
Conclusion: The primary concern regarding a possible space research service (Earth‐to‐
space) uplink within the band 22.55‐23.15 GHz is the EESS primary allocation at 22.21‐22.5
GHz. To protect EESS satellite observations from interference, ITU‐R RS.1029 recommends a
maximum interference level in the 22.21‐22.5 GHz band of ‐249 dBW/Hz, with this
interference level not to be exceeded for more than 0.1% of the sensor viewing area or
measurement time.
1.12 “to protect the primary services in the band 37‐38 GHz from interference resulting from
aeronautical mobile service operations, taking into account the results of ITU R studies, in
accordance with Resolution 754 (WRC 07);”
Conclusion: The primary concern is the continued protection of the 36‐37 GHz EESS
(passive) allocation used by current and future microwave radiometers from the U.S. Air
Force, Navy, NOAA, and NASA, which have been making space‐borne observations near 37
GHz since Scanning Multichannel Microwave Radiometer was launch in 1978. Based upon
scientific requirements expected to be achieved in 2008‐2013, to protect EESS satellite
observations from interference, ITU‐R RS.1029 (2003) recommended a maximum
interference level in the 36.0‐37.0 GHz band of ‐246 dBW/Hz, with this interference level
not to be exceeded for more than 0.1% of the sensor viewing area or measurement time.
1.13 “to consider the results of ITU R studies in accordance with Resolution 551 (WRC 07) and
decide on the spectrum usage of the 21.4‐22 GHz band for the broadcasting‐satellite service
and the associated feeder‐link bands in Regions 1 and 3;”
Recommendation: Satellite transmissions in the 21.4‐22.0 GHz band should have low
enough out of band emissions to avoid interference in the 22.21‐22.5 GHz RAS band based
on Recommendation ITU‐R RA.769.
1.14 “to consider requirements for new applications in the radiolocation service and review
allocations or regulatory provisions for implementation of the radiolocation service in the
range 30 300 MHz, in accordance with Resolution 611 (WRC 07);”
Recommendation: Additional radiolocation service allocations in the 30‐300 MHz band
being considered should avoid the 37.50‐38.25 MHz, 73.00‐74.60 MHz and 150.05‐153.0
MHz passive bands, and should provide suppression of unwanted emissions in these RAS
bands to meet Recommendation ITU‐R RA Rec.769.
1.15 “to consider possible allocations in the range 3‐50 MHz to the radiolocation service for
oceanographic radar applications, taking into account the results of ITU R studies, in
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accordance with Resolution 612 (WRC 07);”
Conclusion: Oceanographic radars operating in 3‐50 MHz do not adversely affect any other
known EESS bands and are thus not of concern for EESS(passive), so long as out‐of‐band RFI
is maintained at levels compatible with Recommendation ITU‐R RS.1029.
Recommendation: Unwanted emissions due to new radar allocations the 3‐50 MHz range
should be low enough to meet the levels of Recommendation ITU‐R RA.769 in the RAS
bands at 13.36‐13.41, 25.56‐25.67 and 37.50‐38.25 MHz.
1.18 “to consider extending the existing primary and secondary radiodetermination‐satellite
service (space‐to‐Earth) allocations in the band 2 483.5‐2 500 MHz in order to make a global
primary allocation, and to determine the necessary regulatory provisions based upon the
results of ITU R studies, in accordance with Resolution 613 (WRC 07);”
Recommendation: Second harmonic radiation emissions into the 4800‐5000 MHz band
should be kept below the level given in Recommendation ITU‐R RA.769 as addressed in
5.402.
1.19 “to consider regulatory measures and their relevance, in order to enable the introduction of
software‐defined radio and cognitive radio systems, based on the results of ITU R studies, in
accordance with Resolution 956 (WRC 07);”
Recommendation: Any modification to existing methods of allocating or managing
spectrum should not result in higher levels or additional instances of harmful interference in
spectrum already allocated for RAS and EESS.
Recommendation: Great care should be taken prior to enactment of new regulations in
order to ensure that new uses of spectrum—especially those in frequencies adjacent to or
harmonically‐related to existing RAS or EESS allocations—do not result in increased levels of
interference to RAS or EESS through unwanted emission.
Recommendation: Representatives of the RAS and EESS spectrum management
communities should be included in deliberations that might lead to the establishment of
universal “beacon” or “pilot” channels, “dynamic databases,” and other technologies
intended to facilitate “dynamic spectrum access” or dynamic changes in other emission
characteristics including modulation type, bandwidth, and power levels.
1.20 “to consider the results of ITU R studies and spectrum identification for gateway links for
high altitude platform stations (HAPS) in the range 5 850‐7 075 MHz in order to support
operations in the fixed and mobile services, in accordance with Resolution 734 (Rev.WRC
07);”
Recommendation: Unwanted emissions should be low enough to meet the levels of
Recommendation ITU‐R RA.769 in RAS frequency allocations if HAPS platforms are deployed
within range of radio astronomy observatories.
Recommendation: Spectrum selected for HAPS gateway links should avoid frequencies used
for Earth observation by current and planned remote sensing satellites in accordance with
Footnote 5.458.
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1.21 “to consider a primary allocation to the radiolocation service in the band 15.4‐15.7 GHz,
taking into account the results of ITU R studies, in accordance with Resolution 614 (WRC
07);”
Recommendation: Radar in the 15.4‐15.7 GHz band should have a sufficiently low level of
unwanted emissions to avoid interference in the adjacent 15.35‐15.40 GHz RAS/EESS band in
accordance with the limits specified in Recommendation ITU‐R RA.769.
1.25 “to consider possible additional allocations to the mobile‐satellite service, in accordance
with Resolution 231 (WRC 07);”
Recommendation: Satellite downlink transmissions should have low enough out of band
emissions to minimize interference with radio astronomy based on Recommendation ITU‐R
RA.769. This applies to uplinks as well, though if well separated from observatory sites,
uplinks are unlikely to cause interference.
Recommendation: Per International Footnote 5.458, “Administrations [are urged to] bear in
mind the needs of the Earth exploration‐satellite (passive) and space research (passive)
services in their future planning” of this frequency range to protect current and future
spaceborne observatories.
8.1.1 “on the activities of the Radiocommunication Sector since WRC 07;”
Conclusion: Earth observation using radiocommunication frequencies has become a key
means to understand the effects of changes in both the natural and artificial environment,
and to provide information for effective decision‐making and resource management in
many areas of society and life. In addition, Earth science and observation technology have
economic benefits, both in job creation and in early warning of potentially disastrous and
disruptive situations. These benefits will continue, and increase as technology pushes
humankind’s understanding of its environment even further.
8.2 “to recommend to the Council items for inclusion in the agenda for the next WRC, and to
give its views on the preliminary agenda for the subsequent conference and on possible
agenda items for future conferences, taking into account Resolution 806 (WRC 07),”
8.2 Recommendation: A secondary allocation for EESS (passive) between 6.425 and 7.250 GHz
should be sought to normalize the radio regulations with the current and planned practical
passive use of the spectrum for Earth observation.
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