The Hill May 20, 2003
Military eyes next-generation GPS technology
By Sarah Lesher
In the 12 years since Desert Storm, global positioning systems (GPS) have gone from being an exotic concept to a system even ATMs use for clock signals.
Precision guided munitions performed spectacularly in Iraq, but the system is not infallible. When Pfc. Jessica Lynch was captured, Americans learned of forward mechanized units that apparently went astray.
Civilian casualties may have been kept down by sophisticated guidance systems, but friendly fire accounted for as much as a quarter of our casualties, up from a few percent in earlier wars.
GPS has a graphic interface in passenger vehicles here at home, but most military units still give a text readout.
Still, GPS has gone far in those 12 years, from one unit per company - roughly 200 troops - to one per 10 and often one per person.
"A decade ago it was almost too big to carry. Now the issue is making it big enough so you don't lose it," said John Pike, a military analyst and director of Globalsecurity.org in Alexandria, Va.
That wasn't yet true in Iraq. Most ground forces were issued "Pluggers," slang for Precision Lightweight GPS Receivers (PLGR), 1994 vintage design, that weigh in at almost three pounds and give only text display of coordinates, time and velocity.
Most of what makes GPS perform smoothly happens behind the scenes at the Air Force Space Command (AFSPC) in Colorado Springs, invisible to both civilian and military users.
"It's really difficult to embed the media" to show them what goes on 24/7 to keep the satellite signals accurate and available, said Col. Edward Rios, Chief Current Operations Division, Air Force Space Command.
"One soldier, when asked what he needed from space, said 'Nothing. I only need my M16 and my GPS,'" said Rios.
But adversaries aren't so naive. There were Iraqi attempts to block GPS signals using Russian jammers.
"If jamming is a problem, this was a good test case. Iraq understood the dependence of the U.S. on GPS, and if there ever was a country that knew we were going to blow them away, it was Iraq," said Pike.
Rios said Iraq's attempts were easily deflected.
"These jammers forget that they transmit a signal. Ironically, when they jammed us, we hit them with JDAM [Joint Direct-Attack Munitions]," said Rios.
Missiles have ballistic guidance systems as backup for when GPS is jammed or fails, and there are multiple redundancies within GPS itself.
"Spoofing" is a more subtle tactic than jamming, changing the signal just enough to give deceptive coordinates, something that could deflect a missile from a military to a civilian target, with serious diplomatic and public relations consequences.
Rios said it would be difficult for terrorists to spoof since it would require changing the signals from satellites, which are uploaded with new instructions every pass. To explore other potential vulnerabilities, AFSPC runs war games where those playing the adversary role try to take out the system.
Systems are under development by NAVSTAR, the GPS Joint Program office at Los Angeles Air Force Base that will offer protection against jamming and spoofing. A new handheld GPS receiver, called a "dagger" (for Defense Advanced GPS Receiver, or DAGR), will be available next year, including a system called SAASM (Selective Availability Anti-Spoofing Module), according to Matthew Brandt, project manager for GPS for the Marines.
One unit, the 4th Mechanized Infantry Division, had vehicles with FBCB2, an advanced graphical GPS system that can display locations of both friendly and hostile units.
But even they did not have GPS in all of their vehicles, and many vehicles with GPS lacked a user interface.
Graphics may become part of new military systems, but Pike pointed out that "it's a lot easier to do guidance in a mass produced commercial environment where if it doesn't work, you can take it to the garage and the worst that happens is that you miss your exit."
Just days ago Lockheed Martin and Spectrum Astro announced a partnership agreement to pursue the development of GPS III, the next generation.
"GPS III brings into the GPS program enhanced accuracy, enhanced availability, enhanced on-orbit integrity in signal and increased power, which will give better anti-jam capability," said Ron Graves, director of Defense Systems at Spectrum Astro in Gilbert, Ariz.
Graves explained that "on-orbit integrity" means having the satellite monitoring its own signal so that it can determine very quickly if it bad, before it leads users astray.
"I think that we have seen the future, and this is what it looks like," Pike said.
"It used to be a slogan in the military: if it moves, salute it. If it doesn't move, paint it. They're still painting things that don't move, but if it moves, it's got GPS," Pike said.
Copyright © 2003, Capitol Hill Publishing Corp.
