IEEE Geoscience and Remote Sensing Magazine - March 2016 - 45

proceedings and meetings with decision makers. This
will build credibility for the science community to ensure a seat at the table for spectrum-related decision
making that impacts the science community.
◗ For the spectrum management process to be effective,
the science community, NASA, NOAA, the National
Science Foundation, and the DoD should also articulate the value of the science-based uses of the radio
frequency spectrum. Such values will include both
economic values, through enabling commerce or reducing the adverse economic impacts of natural phenomena, and noneconomic values that come from scientific research.
Actions by FederAl Agencies
The actions of federal agencies responsible for supporting
scientific uses of active remote sensing and for overseeing
spectrum allocations include the following:
◗ NASA should lead an effort to significantly improve characterization of the radio frequency interference environment
that affects active science measurements. This effort should
include the use of modeling, dedicated ground-based and
airborne characterization campaigns, and data mining of
currently operating scientific sensors. To the extent possible, this effort should be a collaborative one with other
space and science agencies of the world.
◗ NASA should lead a community effort to construct
a set of metrics that relates to the various radio frequency interference environments encountered and
the associated degradation in science performance for
each major class of instruments employed in active
remote sensing.
◗ Radar systems meeting specific criteria for pulse repetition rate, maximum pulse width, and duty cycle should
be permitted by the FCC or the NTIA to operate as secondary users in communication bands where minimal
interference to the communications operations would
be expected to occur.
◗ NASA should facilitate the possibility of time and frequency sharing between the ESA BIOMASS and the
DoD's Space Object Tracking Radar system.
Possible Actions by the
telecommunicAtions industry
◗ The 50-60-GHz millimeter-wave frequency band includes several subbands already allocated to mobile
communications. The use of millimeter-wave frequencies
for short-wave femtocell-sized communications would
significantly increase network capacity by an order of

MARCH 2016

ieee GeoSCienCe and reMote SenSinG MaGazine

magnitude, thereby reducing pressure on the spectrum
and, therefore, on the active remote sensing users as well.
◗ The wireless industry should consider pursuing the femtocell approach by developing towers, networks, and the
like to add the use of millimeter-wave frequencies for
communications in 5G and up.
For a complete set of findings and recommendations of the
NRC study, the reader is directed to the full NRC Active
Sensing Report.
In conclusion, it is important to point out that committees and institutions, such as the NRC Committee on
Radio Frequencies, the Space Frequency Coordination
Group, and the IEEE GRSS Frequency Allocations in Remote Sensing Committee, have been advocating for the
spectrum needs of the scientific community. With increasing pressure on available spectra, it is crucial for the
remote sensing community to support these efforts to address this challenge.
AUTHOR INFORMATION
Michael Spencer is with the Jet Propulsion Laboratory, California Institute of Technology, in Pasadena, California.
Fawwaz Ulaby is with the University of Michigan, Ann
Arbor.
REFERENCES
[1] National Academies of Sciences, Engineering, and Medicine,
Spectrum Management for Science in the 21st Century. Washington,
DC: National Academies Press, 2010.
[2] S. Misra and P. de Matthaeis, "Passive remote sensing and radio
frequency interference (RFI): An overview of spectrum allocations
and RFI management algorithms," IEEE Trans. Geosci. Remote Sensing, vol. 2, no. 2, pp. 68-73, June 2014.
[3] National Academies of Sciences, Engineering, and Medicine,
A Strategy for Active Remote Sensing Amid Increased Demand for
Radio Spectrum. Washington, DC: National Academies Press,
2015.
[4] F. Zhou, M. Tao, X. Bai, and J. Liu, "Narrow-band interference
suppression for SAR based on independent component analysis,"
IEEE Trans. Geosci. Remote Sensing, vol. 51, no. 10, pp. 4952-4960,
Oct. 2013.
[5] F. J. Meyer, J. B. Nicoll, and A. P. Doulgeris, "Correction and
characterization of radio frequency interference signatures
in L-band synthetic aperture radar data," IEEE Trans. Geosci.
Remote Sensing, vol. 51, no. 10, pp. 4961-4972, Oct. 2013.
[6] M. W. Spencer, C. W. Chen, H. Ghaemi, S. F. Chan, and J. E.
Belz, "RFI characterization and mitigation for the SMAP radar,"
IEEE Trans. Geosci. Remote Sensing, vol. 51, no. 10, pp. 4973-4982,
Oct. 2013.

Table of Contents for the Digital Edition of IEEE Geoscience and Remote Sensing Magazine - March 2016