Subject: [NEXTEL-1] Homemade GPS jammers raise concerns

From: Marcel <[email-masked]>
Date: Fri, 28 Mar 2003 14:54:26 -0500

Homemade GPS jammers raise concerns

By Bob Brewin
JANUARY 17, 2003

Government officials and
communications experts are assessing
the public safety and security
implications of a newly posted online
article that provides directions for
making cheap devices that can jam
Global Positioning System (GPS)
signals.

Information in the article that appears in
the current issue of the online hacker
magazine Phrack potentially puts at risk
GPS devices used for commercial
navigation and military operations,
authorities said.

The Phrack article provides a detailed
guide to building a low-cost, portable
GPS jammer out of components that
can be easily obtained from electronics
supply houses. According to the article, the "onslaught of cheap GPS-based navigation (or
hidden
tracking devices) has made it necessary for the average citizen to take up the fine art of
electronic
warfare." Electronics and GPS experts who read the article this week called it technically
competent
and said amateurs with a certain amount of technical skill could build a GPS jammer from
the plans.

Although the article said the jammer is designed to work only against civil-use GPS
signals broadcast
on the frequency of 1575.42 MHz and not the military frequency of 1227.6 MHz, James Hasik,
an
Atlanta-based consultant and author of the book The Precision Revolution: GPS and the
Future of
Aerial Warfare, disagreed.

Hasik said that while the Phrack jammer is targeted at civil GPS signals, known as the C/A
code, it
could also threaten military systems, since "almost all military GPS receivers must first
acquire the
C/A signal" before locking onto the military signal, known as the P(Y) code.

Hasik said that GPS receivers are especially vulnerable to jamming because of low signal
strength
after traveling through space from GPS satellites orbiting 12,000 miles above the earth.

The U.S. Department of Defense, which faces the possibility of having its GPS-guided
weapons come
up against Russian-made GPS jammers in Iraq, has antijamming technology at its disposal.
Still,
Defense officials viewed the Phrack article with concern.

Air Force Lt. Col. Ken. McClellan, a Pentagon spokesman, said the implications of homemade

jammers described in the article are "somewhat serious" because the use of such jammers
"could
disrupt commercial operations."

McClellan said GPS experts at the Pentagon do not "at the moment" view homemade jammers as
a
hazard to flight safety for commercial aircraft or ship operations, "but rather a
nuisance."

The Federal Aviation Administration is developing a nationwide GPS-based precision landing
system.
And the Coast Guard operates a GPS-based maritime navigation system on both coasts, the
Great
Lakes, inland waterways and Hawaii. Bill Mosley, a spokesman for the Department of
Transportation,
the parent agency of the FAA and the Coast Guard, said his department is well aware of the
threat
posed by GPS jammers.

The DOT's John A. Volpe Transportation Systems Center, in Cambridge, Mass., prepared a
report in
August 2001 that said, "Some jamming devices/techniques are available on the Internet and
proliferation will continue, because a single device that could disrupt military and civil
operations
worldwide would be attractive to malicious governments and groups."

As a result of that study, Mosley said, Transportation Secretary Norman Mineta last March
ordered an
"action plan" to protect civilian GPS signals and users by, among other things, "the
transfer of
appropriate antijam technology from the military to civil use." Mosley was unable say
whether that
technology transfer has occurred.

What do you think about GPS jamming? Post your opinions and see what others have to say in
our
discussion forum.

Richard Langley, a GPS expert and professor of geodesy at the University of New Brunswick
in
Fredericton, New Brunswick, called the implications of home-brew GPS jammers "scary." But
he
expressed doubt that the Phrack jammer would be very effective against aircraft when used
from the
ground. However, Langley noted that if a terrorist used the jammer from on board an
aircraft, it would
extend the range and "hence the effectiveness of the jammer."

James Miller, program manager for GPS at United Air Lines Inc., said the loss of a GPS
signal in a
commercial aircraft wouldn't "cause a catastrophic event," because airliners operate with
multiple
navigation systems. But loss of a GPS signal by general aviation aircraft flying solely on
GPS could
be "quite challenging," he said.

Warren Morningstar, a spokesman for the Aircraft Owners and Pilots Association in
Frederick, Md.,
said general aviation pilots don't use GPS as their sole navigation source and called the
potential of
jamming a "nuisance" rather than a safety hazard.

"You need to take it seriously anytime there is publicity about things that could disrupt
the critical
infrastructure," said Mike Swiek, executive director of the U.S. GPS Industry Council in
Washington.
But, Swiek said, "there is no need for panic. All the GPS systems are monitored for any
type of
interference." Swiek noted that while "any garden-variety radio engineer" has the
knowledge to build a
GPS jammer, there have been few reports of any attacks against GPS systems.

Gabe Neville, a spokesman for Rep. Joseph Pitts, (R-Penn.), co-chairman of the House
Electronic
Warfare Working Group, said news of the Phrack story about jamming indicates that GPS
jamming
technology is "easily available" and that the Pentagon needs to beef up its electronic
warfare research
and development budget. But Neville said he doubts a homemade jammer could cause as much
damage or disruption as systems acquired and operated by foreign governments.

http://www.computerworld.com/industrytopics/defense/story/0,10801,77702,00.html

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