Applications in Low-Power Phased Array Weather Radars

204 Pages·2016·10.12 MB·English

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Doctoral Dissertations Dissertations and Theses
March 2016
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Robert A. Palumbo Jr
University of Massachusetts Amherst
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APPLICATIONS IN LOW-POWER PHASED ARRAY
WEATHER RADARS
A Dissertation Presented
by
ROBERT A. PALUMBO
Submitted to the Graduate School of the
University of Massachusetts Amherst in partial fulfillment
of the requirements for the degree of
DOCTOR OF PHILOSOPHY
February 2016
Electrical and Computer Engineering
© Copyright by Robert A. Palumbo 2016
All Rights Reserved
APPLICATIONS IN LOW-POWER PHASED ARRAY
WEATHER RADARS
A Dissertation Presented
by
ROBERT A. PALUMBO
Approved as to style and content by:
Stephen J. Frasier, Chair
Paul Siqueira, Member
Michael Zink, Member
Gopal Narayanan, Member
Christopher V. Hollot, Department Head
Electrical and Computer Engineering
DEDICATION
This is dedicated to my family, who has stuck by me for so long. And to Mikey, who
is one of the few friends who hasn’t given up on me.
Two roads diverged in a wood, and I took the one less traveled by,
and that has made all the difference
—Robert Frost
ACKNOWLEDGMENTS
First and foremost, I’d like to thank Raytheon for giving me the opportunity to
workwitharadarsystemforsolongasIhave. It’saluxurythat’snotoftenaffordedin
large companies, and I’m grateful to have been given the chance to prove myself. I’m
very thankful to both Paul Ferraro and Christopher McCarroll from Raytheon, who
got me started on my graduate career in Amherst and have done everything possible
to keep me going. I’d also like to thank Ilene Hill and everyone in SRSI/SVTAD at
Raytheon for being patient with me through my endeavors.
The radar system wouldn’t nearly be this capable if it weren’t for the efforts of
Ken Wood from Raytheon and Eric Knapp from the University of Massachusetts at
Amherst. Thanks for the long days we spent trying to build and calibrate the first
system and the months trying to commercialize and sell it internationally. I’d also
like to thank the rest of the staff and students at the Microwave Remote Sensing
Laboratory (MIRSL), who have provided a great learning environment with all the
lab equipment and tools needed to get the job done. And special thanks to my
advisor, Steve Frasier, for taking me on as a student and keeping me through the
sometimes long months without contact.
I appreciate all the support and effort from the engineers at FIRST RF Corpora-
tion (Boulder, CO), specifically Luke Sankey, who have built an extremely capable,
affordable, and commercialized phased array system.
Thanks to Professor Douglas Gray and Waddah Al-Ashwal from the University of
Adelaide (South Australia, AU), for the whirlwind of field experiments and trips we
made in such a short time in Australia. That was one of the culminating experiences
of my graduate career, and I’m grateful for all the help.
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Last, but not least, thanks to Richard Moro, Terry Kirn, and David Payne from
AT and SED in Raytheon, who have done a great job in educating me in the finer
points of radar program capture and marketing. It’s an often overlooked and under-
appreciated task, but I’m grateful to be a part of it (and look forward to more future
wins).
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ABSTRACT
APPLICATIONS IN LOW-POWER PHASED ARRAY
WEATHER RADARS
FEBRUARY 2016
ROBERT A. PALUMBO
B.Sc., RENSSELAER POLYTECHNIC INSTITUTE
M.Sc., UNIVERSITY OF MASSACHUSETTS AMHERST
Ph.D., UNIVERSITY OF MASSACHUSETTS AMHERST
Directed by: Professor Stephen J. Frasier
Low-cost X-band radars are an emerging technology that offer significant ad-
vantages over traditional systems for weather remote sensing applications. X-band
radars provide enhanced angular resolution at a fraction of the aperture size com-
pared to larger, lower frequency systems. Because of their low cost and small form
factor, these radars can now be integrated into more research and commercial ap-
plications. This work presents research and development activities using a low-cost,
X-band (9410MHz) Phase-Tilt Radar. The phase-tilt design is a novel phased ar-
ray architecture that allows for rapid electronic scanning in azimuth and mechanical
tilting in elevation, as a compromise between cost and performance.
This work focuses on field studies and experiments in three meteorological appli-
cations. The first stage of research focuses on the real-world application of phased
array radars in forest fire monitoring and observation. From April to May 2013, a
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phase-tilt radar was deployed to South Australia and underwent a field campaign to
make polarimetric observations of prescribed burns within and around the Adelaide
Hills region. Measurements show the real-time evolution of the smoke plume dynam-
ics at a spatial and temporal resolution that has never before been observed with an
X-band radar. This dissertation will perform data analysis on results from this field
campaign. Results are compared against existing work, theories, and approaches.
In the second stage of research, field experiments are performed to assess the data
quality of X-band phased array radars. Specifically, this research focuses on the mea-
surement of and techniques to improve the variance of weather product estimators
for dual-polarized systems. Variability in the radar products is a complicated rela-
tionship between the radar system specifications, scanning strategy, and the physics
governing precipitation. Here, the variance of the radar product estimators is mea-
sured using standard radar scanning strategies employed in traditional mechanical
antenna systems. Results are compared against adaptive scan strategies such as
beam multiplexing and frequency diversity. This work investigates the improvement
that complex scanning strategies offer in dual-polarized, X-band phased array radar
systems.
In the third stage of research, simulations and field experiments are conducted
to investigate the performance benefits of adaptive scanning to optimize the data
quality of radar returns. This research focuses on the development and implemen-
tation of a waveform agile and adaptive scanning strategy to improve the quality
of weather product estimators. Active phased array radars allow radar systems to
quickly vary both scan pointing angles and waveform parameters in response to real-
time observations of the atmosphere. As an evolution of the previous research effort,
this work develops techniques to adaptively change the scan pointing angles, trans-
mit and matched filter waveform parameters to achieve a desired level of data quality.
Strategies and techniques are developed to minimize the error between observed and
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