Three Times a Winner
Electrical Engineering Professor
at Cal State Fullerton Chosen
Among 50 Worldwide to Watch in Field of Satellite
Navigation
May 30, 2007 :: No. 222
It’s a little like winning the office pool on the
Stanley Cup Finals, then going home to find you got an unexpected
tax rebate, too. And both of those just a few months after
winning a trophy.
Mohinder Grewal, professor of electrical engineering, was
just posted online in the May issue of GPS World as
one of the “50+ Leaders to Watch” in 2007 and
2008 for advancements in space-based positioning, navigation
and timing systems. Those leaders are chosen from among the
many thousands worldwide in scientific and engineering disciplines
involved in global positioning and navigation.
“As the year continues to unfold, look for these individuals,
as well as their companies and organizations, to bring further
innovation to an already dynamic field,” states GPS
World in the introduction
to “50+ Leaders to Watch.”
An energetic Grewal was very pleased: “I feel very
good about this. It is an exclusive group, and they are from
around the world. I know most of them and am aware of the
work of all of them.”
The professor said he expects
to see most of them Sept. 25-28 in Fort Worth, Texas, during
the Institute of Navigation Conference on Global Navigation
Satellite Systems (GNSS). “I
will be giving a tutorial on WAAS — that is Wide Area
Augmentation System — at the conference.”
WAAS
is another of the three “wins” Grewal has
had lately. In April, he was informed by Robin R. Loporchio
of Raytheon Co.’s Waltham, Mass., office that Raytheon
has submitted to the U.S. Patent Office Grewal’s mathematical
algorithm to improve navigation via WAAS. The full
title is “Method and Apparatus for Wide Area Augmentation
System Having Geo Uplink Subsystem With Enhanced Clock Steering.”
Grewal
said that although the process is still under way, he expects
to get the patent. He speaks from experience, since he acquired
a patent for similar work on satellite navigation systems.
That one refined and improved calculating time differentials
between when the satellite sees a moving object, such as
an aircraft, and when the data gets back to the aircraft
to tell it exactly where it is.
The new algorithm now in the U.S. Patent office does something
similar: “It corrects the signal being sent. There
can be errors in the data given by the Global Positioning
Satellites. They orbit the Earth and, therefore, are in motion,
which can introduce errors, as can the time difference between
when the data is sent and when it gets back to the target.
Atmospheric interference and ionization from the sun’s
radiation can introduce errors, too, that need to be corrected,” Grewal
said.
“That data gets sent to a ground station
for calculations, then is sent back up to a geostationary
satellite — which
does not orbit, but stays over the same part of the Earth
all the time — then back to the aircraft,
or automobile or ship. The new algorithm further refines correcting for those
errors, including the time differential, which is called steering the clock.
The clock is steered to within a nanosecond.
“You just can’t have
a 10-meter error when an airplane is landing,” Grewal
said.
In January, the first of Grewal’s “wins” was
the second edition of his book on global positioning and
inertial navigation systems, “Global Positioning Systems,
Inertial Navigation and Integration,” published by
Wiley & Sons. Co-authors are Lawrence R. Weill, CSUF
emeritus professor of mathematics, and Angus P. Andrews,
retired senior scientist for Rockwell.
The book is
a guide to Global Navigation Satellite Systems and Inertial
Navigation Systems and the integration of the two. The book
includes a CD and offers solutions to real-world Global Positioning
Systems (GPS) problems. GPS is used in everyday life. Besides
aircraft and automobile navigation, it is used in cell phones,
national security, commercial fishing and geocaching, even
golf.
The first edition of Grewal’s book was published in
2001 and used worldwide. A number of reviewers have called
the book a landmark.
But that was not Grewal’s first
book. In 1993, the first edition of “Kalman Filtering:
Theory and Practice Using MATLAB” was published, also
by John Wiley & Sons.
The second edition was published in 2001, and the professor
is working on the third edition now, with an anticipated
release date in early 2008.
Kalman
filtering is an integral part of GPS technology, so his books
are complementary, he said.
The professor also has authored
and co-authored dozens of articles and papers on navigation
and global positioning and has given many presentations,
lectures and seminars.
Grewal earned his Ph.D. at USC and
joined the Cal State Fullerton faculty in 1975.
Media Contacts: |
Mohinder Grewal, Electrical Engineering, 657-278-3874
or
mgrewal@fullerton.edu
Russ
L. Hudson, Public Affairs, 657-278-4007 or rhudson@fullerton.edu |
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