Solar Bursts Threaten GPS, Communications
Pastor Dale Morgan
Apr 4, 5:09 PM EDT
*Solar Bursts Threaten GPS, Communications *
By RANDOLPH E. SCHMID
AP Science Writer
WASHINGTON (AP) -- The Global Positioning System, relied on for
everything from navigating cars and airplanes to transferring money
between banks, may be threatened by powerful solar flares, a panel of
scientists warned Wednesday.
"Our increasingly technologically dependent society is becoming
increasingly vulnerable to space weather," David L. Johnson, director of
the National Weather Service, said at a briefing.
GPS receivers have become widely used in recent years, using satellite
signals in navigating airplanes, ships and automobiles, and in using
cell phones, mining, surveying and many other commercial uses.
Indeed, banks use the system to synchronize money transfers, "so space
weather can affect all of us, right down to our wallet," said Anthea J.
Coster, an atmospheric scientist at the Haystack Observatory of the
Massachusetts Institute of Technology.
The cause for their concern, Johnson said, was an unexpected solar radio
burst on Dec. 6 that affected virtually every GPS receiver on the
lighted half of Earth. Some receivers had a reduction in accuracy while
others completely lost the ability to determine position, he said.
Solar activity rises and falls in 11-year cycles, with the next peak
expected in 2011.
If that increasing level of activity produces more such radio bursts the
GPS system could be seriously affected, the researchers said.
And protecting the system is no simple task, added Paul M. Kintner Jr.,
a professor of electrical engineering at Cornell University, who
monitored the December event.
There are two possible ways to shield the system, he said, both very
expensive. Either alter all GPS antennas to screen out solar signals or
replace all of the GPS satellites with ones that broadcast a stronger
signal.
That's why it's essential to learn more about the sun's behavior quickly
in an effort to find ways to predict such events, the researchers said.
In addition to the GPS system, the December solar flare affected
satellites and induced unexpected currents in the electrical grid,
Johnson said.
"The effects were more profound than we expected and more widespread
than we expected," added Kintner.
Dale E. Gary, chairman of the physics department of the New Jersey
Institute of Technology, said the burst produced 10 times more radio
noise than any burst previously recorded.
The difference between that burst and normal solar radio emissions "was
like the difference between the noise level of a normal conversation and
the noise level in the front row of a rock concert," he said.
"This is a wake-up call" to improve technology, commented Anthony J.
Mannucci, group supervisor at NASA's Jet Propulsion Laboratory.
Patricia H. Doherty, co-director of the Institute for Scientific
Research at Boston College, said the burst affected but did not shut
down the Federal Aviation Administration's Wide Area Augmentation
System, which uses GPS signals to assist in navigation.
Most of the WAAS ground stations were able to maintain contact with
enough satellites to continue working, though their accuracy was
somewhat affected, she said.
The stations have to maintain contact with at least four satellites to
work, but usually monitor at least 10 to increase their accuracy, she
said. Most were able to meet the minimum, she said.
The briefing came at a Space Weather Enterprise Forum convened by the
National Oceanic and Atmospheric Administration to discuss the effects
of solar activity. Because of its increasing importance, Johnson said,
the Weather Service's Space Environment Center was converted from a
mainly research center in 2005 to an operational center reporting on
solar activity and its impacts.
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On the Net
National Oceanic and Atmospheric Administration: http://www.noaa.gov
National Weather Service: http://www.nws.noaa.gov
Space Environment Center: http://www.sec.noaa.gov