A STRATEGY FOR
ACTIVE REMOTE SENSING
AMID INCREASED DEMAND
FOR RADIO SPECTRUM
Committee on a Survey of the Active Sensing
Uses of the Radio Spectrum
Board on Physics and Astronomy
THE NATIONAL ACADEMIES PRESS
Washington, DC
THE NATIONAL ACADEMIES PRESS 500 Fifth Street, NW Washington, DC 20001
This study was supported by the National Aeronautics and Space Administration under Contract NNH10CD04B, TO#6. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the organizations or agencies that provided support for the project.
International Standard Book Number-13: 978-0-309-37305-0
International Standard Book Number-10: 0-309-37305-0
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Suggested citation: National Academies of Sciences, Engineering, and Medicine. 2015. A Strategy for Active Remote Sensing Amid Increased Demand for Radio Spectrum. Washington, DC: The National Academies Press.
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COMMITTEE ON A SURVEY OF THE ACTIVE SENSING USES OF THE RADIO SPECTRUM
FAWWAZ ULABY, University of Michigan, Chair
SUSAN AVERY, Woods Hole Oceanographic Institute
COLEMAN BAZELON, The Brattle Group
WILLIAM BRISTOW, University of Alaska, Fairbanks
DONALD B. CAMPBELL, Cornell University
MARIE COLTON, NOAA Great Lakes Environmental Research Laboratory (retired)
SANDRA CRUZ-POL, University of Puerto Rico-Mayaguez (resigned August 2014)
LENNARD FISK, University of Michigan
ALBIN GASIEWSKI, University of Colorado, Boulder
JEFFREY HERD, MIT Lincoln Laboratory
LINWOOD JONES, University of Central Florida
PAUL KOLODZY, Kolodzy Consulting
ROBERT PALMER, University of Oklahoma
DEAN PASCHEN, First RF Co.
MICHAEL SPENCER, Jet Propulsion Laboratory, California Institute of Technology
DAVID LONG, Brigham Young University, consultant to the committee
Staff
DAVID B. LANG, Senior Program Officer, Study Director
JAMES C. LANCASTER, Director, Board on Physics and Astronomy
LINDA WALKER, Program Coordinator
BETH DOLAN, Financial Associate
BOARD ON PHYSICS AND ASTRONOMY
MICHAEL S. WITHERELL, University of California, Santa Barbara, Chair
CHARLES L. BENNETT, Johns Hopkins University, Vice Chair
RICCARDO BETTI, University of Rochester
TODD DITMIRE, University of Texas, Austin
NATHANIEL J. FISCH, Princeton University
PAUL FLEURY, Yale University
GERALD GABRIELSE, Harvard University
JACQUELINE N. HEWITT, Massachusetts Institute of Technology
BARBARA V. JACAK, Stony Brook University
BARBARA JONES, IBM Almaden Research Center
HERBERT LEVINE, Rice University
ABRAHAM (AVI) LOEB, Harvard University
MONICA OLVERA DE LA CRUZ, Northwestern University
PAUL SCHECHTER, Massachusetts Institute of Technology
Staff
JAMES C. LANCASTER, Director
DAVID B. LANG, Senior Program Officer
LINDA WALKER, Program Coordinator
BETH DOLAN, Financial Associate
Preface
To support the presidential initiative for Spectrum Management for the 21st Century, a review of current and future needs of scientific users of the spectrum is in order. In recent years, the explosion of new wireless technologies has significantly increased the demand for access to the radio spectrum. The increased demand has led to discussions in both government and industry about new ways of thinking about spectrum allocation and use.
Scientific users of the radio spectrum (such as radio astronomers and Earth scientists using remotely sensed data) have an important stake in the policies which will result from this activity. A survey of the scientific uses of the spectrum up to 3 THz by passive (receive-only) means was conducted by the National Research Council (NRC), resulting in “Spectrum Management for Science in the 21st Century” (SMS). Identifying the potentially dire interference situation posed to NASA’s in-orbit and planned passive remote sensing observatories and to the National Science Foundation’s ground-based radio astronomy observatories, the report had a significant amount of impact in the Administration and Congress.
NASA requested that the NRC immediately embark on a similar study to explore the current and planned scientific use of the spectrum by active means and the current and potential vulnerabilities and problem areas therein. This information will assist spectrum management decision makers in balancing the requirements of the scientific users of the spectrum with other interests.
With funding from NASA, the NRC convened the Committee on a Survey of the Active Scientific Use of the Radio Spectrum to conduct this study and issue a report. The committee first met in Washington, D.C. on August 15-16, 2013, at
which it heard from government policymakers. The subsequent 3 meetings over the following year featured discussions with experts and stakeholders from academia, government labs, industry, and foreign interests. In particular, the committee organized a one-day workshop to gather information on radiofrequency interference experiences by operating spaceborne active remote sensing platforms. This workshop was held at the Jet Propulsion Laboratory on November 8, 2013, and an account of the meeting is provided in the appendix to this report.
In the course of its discussions the transmission of collected data arose (for example, NASA’s Deep Space Network) as a possible topic for the committee to include in its report. However, after discussion, the committee and sponsors concluded that, while crucial in its own right, that it is outside of the committee’s purview and expertise and thus should not be treated in this report. Both the sponsor and committee agreed that an in-depth look at data transmission could indeed be a separate and valuable study following this one.
In writing its report the committee presents the scientific and technical bases for the multiple applications of active remote sensing in separate chapters: the atmosphere; the oceans; the land surfaces; space physics; and radar astronomy. These chapters (Chapters 2-6) also summarize the spectrum usage for each remote sensing and radiofrequency interference environment for each application. A later chapter (Chapter 8) discusses in greater detail radiofrequency interference issues for active sensing instruments. Finally, Chapter 7 provides an overview of spectrum allocation policies and the frequency assignment process, and Chapter 9 knits the report together by recommending unilateral and cooperative strategies for enhanced usage of the spectrum by all parties, including commercial interests.
This report provides useful information and guidance to engineers who operate the current suite of spacecraft and those who will build future observatories; scientists who use the information gleaned by these spacecraft; policymakers who must balance multiple competing priorities; and the telecommunications industry which is facing ever-increasing demand. The forward-looking approach laid out in this report allows scientists to continue to provide the nation and world with an improving understanding of Earth and the local solar system while working cooperatively alongside other spectrum users in an era of ever-increasing demand for bandwidth.
Acknowledgment of Reviewers
This report has been reviewed in draft form by individuals chosen for their diverse perspectives and technical expertise, in accordance with procedures approved by the Report Review Committee of the National Academies of Sciences, Engineering, and Medicine. The purpose of this independent review is to provide candid and critical comments that will assist the institution in making its published report as sound as possible and to ensure that the report meets institutional standards for objectivity, evidence, and responsiveness to the study charge. The review comments and draft manuscript remain confidential to protect the integrity of the deliberative process. We wish to thank the following individuals for their review of this report:
William J. Blackwell, Massachusetts Institute of Technology,
V. Chandra Chandrasekar, Colorado State University,
Bryan Huneycutt, Jet Propulsion Laboratory,
David L. Hysell, Cornell University,
Kenneth Jezek, The Ohio State University,
Jean-Luc Margot, University of California, Los Angeles,
James J. Reis, Fugro EarthData,
Gregory Rosston, Stanford Institute for Economic Policy Research,
David T. Sandwell, Scripps Institute of Oceanography,
Robert J. Serafin, National Center for Atmospheric Research, and
Paul Siqueira, University of Massachusetts.
Although the reviewers listed above have provided many constructive comments and suggestions, they were not asked to endorse the conclusions or recommendations nor did they see the final draft of the report before its release. The review of this report was overseen by Ken Kellermann, National Radio Astronomy Observatory, who was responsible for making certain that an independent examination of this report was carried out in accordance with institutional procedures and that all review comments were carefully considered. Responsibility for the final content of this report rests entirely with the authoring committee and the institution.
Contents
Scientific Applications and Societal Benefits
Radio-Frequency Interference and Mitigation Opportunities
2 ACTIVE EARTH REMOTE SENSING FOR ATMOSPHERIC APPLICATIONS
Layers of the Atmosphere and Scientific Applications
Atmospheric Scattering/Reflection Mechanisms
Ground-Based Radar Systems Used to Observe the Atmosphere
Satellite-Based Radar Systems Used to Observe the Atmosphere
Spectrum Usage Requirements for Satellite-Based Sensing
Technical Basis for Airborne/Spaceborne Active Earth Remote Sensing of Oceans
4 ACTIVE EARTH REMOTE SENSING FOR LAND SURFACE APPLICATIONS
Science and Applications of Active Microwave Remote Sensing of Earth’s Surface
Spectrum Issues for Microwave Remote Sensing of the Land Surface
5 ACTIVE REMOTE SENSING FOR SPACE PHYSICS
Scientific and Other Applications
Current Radar Astronomy Systems
Future Science Drivers and Technical Requirements
Frequency Assignment Requirements
7 SPECTRUM ACCESS: ALLOCATION POLICIES AND THE ASSIGNMENT PROCESS
Spectrum Allocation and Assignment
Spectrum Allocation Issues for CubeSats
Estimating the Value of Active Sensing
8 RADIO-FREQUENCY INTERFERENCE ISSUES FOR ACTIVE SENSING INSTRUMENTS
Science Sensor Transmit Restrictions
Current Spectrum Issues by Frequency Band
9 TECHNOLOGY AND THE OPPORTUNITIES FOR INTERFERENCE MITIGATION
Unilateral Techniques and Strategies
Sharing Techniques and Strategies
Best Opportunities for Sharing
Limitations of Mitigation Techniques and Strategies
B Committee Meeting and Workshop Agendas
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