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[] WSJ 24.09.02: U.S. Military's GPS Reliance Makes A Cheap, Easy Target,

Wall Street Journal September 24, 2002

U.S. Military's GPS Reliance Makes A Cheap, Easy Target

By Anne Marie Squeo, Staff Reporter of The Wall Street Journal

The hugely successful satellite-based technology that has enabled a growing 
number of U.S. bombs to hit their targets may be vulnerable to a kind of 
jammer available through the Internet for $39.99.

That could mean potential problems in any invasion of Iraq. In recent 
months, the Pentagon has stepped up orders for precision-guided bombs that 
use Global Positioning System satellites to hit targets with pinpoint 
accuracy, and is expected to rely on them for surgical strikes on Saddam 
Hussein's military infrastructure.

Bombs that use GPS-guidance systems were employed heavily in the U.S. 
campaign in Afghanistan. Air Force officials estimate 95% of Boeing's Joint 
Direct Attack Munitions landed within 10 to 30 feet of their targets, well 
above performance thresholds originally set for the weapons.

But with Iraq expected to force the U.S. to fight in the tight spaces of 
Baghdad -- as opposed to the expansive desert where most clashes took place 
during the Gulf War -- highly accurate weapons could mean the difference 
between hitting a hospital and a military building. But the more reliant 
the U.S. has become on GPS over the past decade, for both military and 
civilian use, the more people have developed systems that can misdirect or 
even stymie the technology.

GPS "jammers," now available via the Internet for as little as $39.99, can 
easily interrupt the signal coming from the satellite system in a local 
area. At the Paris Air Show in 1999, a Russian company called Aviaconversia 
demonstrated a 4-watt GPS jammer, weighing about 19 pounds, capable of 
denying GPS reception for more than 100 miles. (By comparison, most hair 
dryers today have at least 18 watts of power.)

That has caught the attention of military officials and politicians alike. 
"We believe Saddam Hussein has GPS-jamming capability and that he will use 
it," says Rep. Joseph Pitts (R., Penn.).

He is co-chairman of the Electronic Warfare Working Group, whose members 
include 25 congressmen who have been studying GPS vulnerability, among 
other issues. "While we do not know the extent of our vulnerability, there 
is evidence to suggest that GPS jamming can significantly inhibit precision 
targeting," Mr. Pitts added. One congressional staffer noted it is also 
possible to "spoof" the system, or provide incorrect satellite readings 
that could misdirect a weapon.

Conceived by the military in the late 1970s, GPS is a constellation of 24 
satellites that circle the globe twice a day, continuously beaming radio 
signals that provide timing and other information to anyone with a 
receiver. Air Force Col. Douglas Loverro, who oversees the program, likens 
it to "rainwater." But the signals travel 11,000 miles from satellite to 
Earth's surface, making them so weak by the time they arrive that a single 
Christmas tree light is about 1,000 times as bright.

The current GPS satellites emit two signals -- one dedicated to the 
military and another that has been made available to commercial users 
around the world, including as a timing device for big computerized 
networks such as telecommunications and transportation systems.

The military signal is configured so it is more difficult to interrupt. But 
the problem is that the military uses the commercial signal, which is more 
readily available, to "find" the military one. And while some efforts are 
under way to develop technology that enables aircraft to access the 
military signal directly, an Air Force spokesman said that isn't being done 

"It turns out that intentional jamming is far more of a problem for the 
military than civilian users," says Col. Loverro.

Military officials refuse to say whether GPS signals have been jammed in 
battle and what specific fixes are being put in place, citing the 
classified nature of such information. They admit that concerns about the 
system's vulnerability are taking on increased prominence, especially as 
they relate to Iraq.

"Everyone knows how successful these [JDAM] weapons are so we know that 
they are going to try to take them away from us," says Richard Walley, 
chief of program development for the Pentagon's JDAM program office. Both 
the Navy and Air Force use JDAMs.

The only bona fide fix is strengthening signal power. Such efforts are 
under way, with the Air Force planning three stages of upgraded satellites 
over the next 10 to 15 years. The launch of these spacecraft has been 
delayed in part because the current fleet has lasted longer than expected. 
Technical challenges and budgetary decisions have also played a role in the 

-- Greg Jaffe contributed to this article.

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