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 (1) advanced receiver technology with extreme sensitivity and (2) 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—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 from 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 discussions in preparation for the next World Radiocommunication Conference (WRC), which will be held in January and February 2012 in Geneva, Switzerland. At the request of the National Science Foundation and NASA, a committee of the U.S. National Research Council was convened to provide guidance to U.S. spectrum managers and policy makers as they prepare for the WRC in order to protect the scientific exploration of Earth and the universe using the radio spectrum (see Appendix A 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 relevant to radio astronomers and Earth remote-sensing researchers and that could impact them. It does not discuss the numerous other agenda items.

The committee’s consensus on the potential impact and relevance of certain agenda items at issue at the WRC in 2012 is presented in the main body of this report. Its conclusions and recommendations are addressed to Administrations1 preparing for WRC are listed in Table ES.1.

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1 Defined by the ITU as “[a]ny governmental department or service responsible for discharging the obligations undertaken in the Constitution of the International Telecommunication Union, in the Convention of the International Telecommunication Union and in the Administrative Regulations.” From http://www.itu.int/net/about/basic-texts/constitution/annex.aspx, accessed September 22, 2011.



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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 (1) advanced receiver technology with extreme sensitivity and (2) 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—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 from 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 discussions in preparation for the next World Radiocommunication Conference (WRC), which will be held in January and February 2012 in Geneva, Switzerland. At the request of the National Science Foundation and NASA, a committee of the U.S. National Research Council was convened to provide guidance to U.S. spectrum managers and policy makers as they prepare for the WRC in order to protect the scientific exploration of Earth and the universe using the radio spectrum (see Appendix A 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 relevant to radio astronomers and Earth remote-sensing researchers and that could impact them. It does not discuss the numerous other agenda items. The committee’s consensus on the potential impact and relevance of certain agenda items at issue at the WRC in 2012 is presented in the main body of this report. Its conclusions and recommendations are addressed to Administrations 1 preparing for WRC are listed in Table ES.1. 1 Defined by the ITU as “[a]ny governmental department or service responsible for discharging the obligations undertaken in the Constitution of the International Telecommunication Union, in the Convention of the International Telecommunication Union and in the Administrative Regulations.” From http://www.itu.int/net/about/basic- texts/constitution/annex.aspx, accessed September 22, 2011. 1

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TABLE ES.1 WRC-12 Agenda Items of Relevance and Potential Impact to RAS and EESS and the Associated Conclusions and Recommendations of the Committee Agenda Conclusion and/or Recommendation of the Item Text of Agenda Item Committee 1.3 To consider spectrum requirements and possible Recommendation: Transmissions in support of regulatory actions, including allocations, in order unmanned aircraft in the 5030-5150 MHz band to support the safe operation of unmanned aircraft should have a sufficiently low level of unwanted systems (UAS), based on the results of ITU-R emissions to avoid interference in the adjacent studies, in accordance with Resolution 421 (WRC Radio Astronomy Service bands in accord with 07). Recommendation ITU-R RA.769. 1.4 To consider, based on the results of ITU R studies, Recommendation: Transmitters providing surface any further regulatory measures to facilitate applications at airports in the 5000-5030 MHz introduction of new aeronautical mobile (R) band should have sufficient suppression of out-of- service (AM(R)S) systems in the bands 112- band emissions to avoid interference in the 117.975 MHz, 960-1 164 MHz and 5 000-5 030 adjacent 5 GHz Radio Astronomy Service band in MHz in accordance with Resolutions 413 accord with Recommendation ITU-R RA.769. (Rev.WRC 07), 417 (WRC 07) and 420 (WRC 07). 1.6 To review No. 5.565 of the Radio Regulations in Recommendation: Administrations should protect order to update the spectrum use by the passive the bands given in Tables 2.1 and 2.2 from services between 275 GHz and 3 000 GHz, in harmful interference so they may be used by the accordance with Resolution 950 (Rev.WRC 07), Radio Astronomy Service and Earth Exploration- and to consider possible procedures for free-space Satellite Service, respectively. optical-links, taking into account the results of ITU R studies, in accordance with Resolution 955 (WRC 07). 1.7 To consider the results of ITU R studies in Recommendation: AM(R)S transmissions in the accordance with Resolution 222 (Rev.WRC 07) in overlapping and adjacent bands should have out- order to ensure long-term spectrum availability of-band emissions below –237 dBW/(m2Hz) at and access to spectrum necessary to meet registered Radio Astronomy Service sites, in requirements for the aeronautical mobile-satellite accordance with Recommendation ITU-R RA.769 (R) service, and to take appropriate action on this for spectroscopic observations. 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. 1.8 To consider the progress of ITU R studies Recommendation: Administrations are urged to concerning the technical and regulatory issues protect the passive services from harmful relative to the fixed service in the bands between interference in 71-238 GHz. Per Tables 2.4 and 71 GHz and 238 GHz, taking into account 2.5, this band is extremely important for a wide Resolutions 731 (WRC 2000) and 732 (WRC range of scientific problems, both for Radio 2000)” Astronomy Service and Earth Exploration-Satellite Service. continues 2

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TABLE ES.1 Continued Agenda Conclusion and/or Recommendation of the Item Text of Agenda Item Committee 1.11 To consider a primary allocation to the space Conclusion: The primary concern regarding a research service (Earth-to-space) within the band possible space research service (Earth-to-space) 22.55-23.15 GHz, taking into account the results uplink within the band 22.55-23.15 GHz is the of ITU R studies, in accordance with Resolution EESS primary allocation at 22.21-22.5 GHz. To 753 (WRC 07). 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 Conclusion: The primary concern is the continued GHz from interference resulting from aeronautical protection of the 36-37 GHz EESS (passive) mobile service operations, taking into account the allocation used by current and future microwave results of ITU R studies, in accordance with radiometers from the U.S. Air Force and the Navy, Resolution 754 (WRC 07). NOAA, and NASA, which have been making spaceborne observations near 37 GHz since the Scanning Multichannel Microwave Radiometer was launched 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 Recommendation: Satellite transmissions in the accordance with Resolution 551 (WRC 07) and 21.4-22.0 GHz band should have low enough out- decide on the spectrum usage of the 21.4-22 GHz of-band emissions to avoid interference in the band for the broadcasting-satellite service and the 22.21-22.5 GHz Radio Astronomy Service band associated feeder-link bands in Regions 1 and 3. based on Recommendation ITU-R RA.769. 1.14 To consider requirements for new applications in Recommendation: Additional radiolocation the radiolocation service and review allocations or service allocations in the 30-300 MHz band being regulatory provisions for implementation of the considered should avoid the 37.50-38.25 MHz, radiolocation service in the range 30-300 MHz, in 73.00-74.60 MHz, and 150.05-153.0 MHz passive accordance with Resolution 611 (WRC 07). bands and should provide suppression of unwanted emissions in these Radio Astronomy Service bands to meet Recommendation ITU-R RA.769. continues 3

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TABLE ES.1 Continued Agenda Conclusion and/or Recommendation of the Item Text of Agenda Item Committee 1.15 To consider possible allocations in the range 3-50 Conclusion: Oceanographic radars operating in 3- MHz to the radiolocation service for 50 MHz do not adversely affect any other known oceanographic radar applications, taking into EESS bands and are thus not of concern for account the results of ITU R studies, in accordance EESS(passive), so long as out-of-band radio with Resolution 612 (WRC 07). frequency interference is maintained at levels compatible with Recommendation ITU-R RS.1029. Recommendation: Unwanted emissions due to new radar allocations in the 3-50 MHz range should be low enough to meet the levels of Recommendation ITU-R RA.769 in the Radio Astronomy Service 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 Recommendation: Second harmonic radiation secondary radiodetermination-satellite service emissions into the 4800-5000 MHz band should be (space-to-Earth) allocations in the band 2 483.5-2 kept below the level given in 500 MHz in order to make a global primary Recommendation ITU-R RA.769 as addressed in allocation, and to determine the necessary 5.402. regulatory provisions based upon the results of ITU R studies, in accordance with Resolution 613 (WRC 07). 1.19 To consider regulatory measures and their Recommendation: Any modification to existing relevance, in order to enable the introduction of methods for allocating or managing spectrum software-defined radio and cognitive radio should not result in higher levels or additional systems, based on the results of ITU R studies, in instances of harmful interference in spectrum accordance with Resolution 956 (WRC 07). already allocated for Radio Astronomy Service and Earth Exploration-Satellite Service. Recommendation: Great care should be taken prior to enactment of new regulations to ensure that new uses of spectrum—especially those in frequencies adjacent to or harmonically related to existing Radio Astronomy Service (RAS) or Earth Exploration-Satellite Service (EESS) allocations— do not result in increased levels of interference to RAS or EESS through unwanted emission. Recommendation: Representatives of the Radio Astronomy Service and Earth Exploration-Satellite Service 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. continues 4

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TABLE ES.1 Continued Agenda Conclusion and/or Recommendation of the Item Text of Agenda Item Committee 1.21 To consider a primary allocation to the Recommendation: Radar in the 15.4-15.7 GHz radiolocation service in the band 15.4-15.7 GHz, band should have a sufficiently low level of taking into account the results of ITU R studies, in unwanted emissions to avoid interference in the accordance with Resolution 614 (WRC 07). adjacent 15.35-15.40 GHz Radio Astronomy Service/ Earth Exploration-Satellite Service band in accordance with the limits specified in Recommendation ITU-R RA.769. 1.25 To consider possible additional allocations to the Recommendation: Satellite downlink mobile-satellite service, in accordance with transmissions should have low enough out-of-band Resolution 231 (WRC 07). 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: According to 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 Conclusion: Earth observation using Sector since WRC 07. radiocommunication frequencies has become a key means of understanding the effects of changes in both the natural and artificial environment, and of providing 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 mankind’s understanding of its environment even further. 8.2 To recommend to the Council items for inclusion Recommendation: A secondary allocation for in the agenda for the next WRC, and to give its Earth Exploration-Satellite Service (passive) views on the preliminary agenda for the between 6.425 and 7.250 GHz should be sought to subsequent conference and on possible agenda normalize the radio regulations with the current items for future conferences, taking into account and planned practical passive use of the spectrum Resolution 806 (WRC 07). for Earth observation. 5

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TABLE ES.1 Continued Agenda Conclusion and/or Recommendation of the Item Text of Agenda Item Committee 1.20 To consider the results of ITU R studies and Recommendation: Unwanted emissions should be spectrum identification for gateway links for high low enough to meet the levels of Recommendation altitude platform stations (HAPS) in the range 5 ITU-R RA.769 in Radio Astronomy Service 850-7 075 MHz in order to support operations in frequency allocations if HAPS platforms are the fixed and mobile services, in accordance with deployed within range of radio astronomy Resolution 734 (Rev.WRC 07). 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 ITU Footnote 5.458. NOTE: AM(R)S, Aeronautical Mobile (R) Service; EESS, Earth Exploration-satellite Service; HAPS, high altitude platform stations; ITU, International Telecommunications Union; ITU-R, International Telecommunications Union- Radiocommunication; NOAA, U.S. National Oceanic and Atmospheric Administration; NASA, U.S. National Aeronautics and Space Administration; RAS, Radio Astronomy Service; WRC, World Radiocommunication Conference. SOURCE: Agenda items from the International Telecommunications Union-Radiocommunication Sector website, available at http://www.itu.int/ITU-R/index.asp?category=study-groups&rlink=rcpm-wrc-12-studies&lang=en, accessed July 28, 2010. 6