White House Wants Plans For GPS Shutdown

NATO AIR · Dec 16, 2004

never say our prez wasn't trying to be prepared for whatever

http://www.msnbc.msn.com/id/6720387/

White House wants plans for GPS shutdown
Global Positioning System
would be disabled during crisis
to keep enemies from using it

By Ted Bridis
Technology Writer
The Associated Press
Updated: 8:54 p.m. ET Dec. 15, 2004
WASHINGTON - President Bush has ordered plans for temporarily disabling the U.S. network of global positioning satellites during a national crisis to prevent terrorists from using the navigational technology, the White House said Wednesday.

Any shutdown of the network inside the United States would come under only the most remarkable circumstances, said a Bush administration official who spoke to a small group of reporters at the White House on condition of anonymity.

The GPS system is vital to commercial aviation and marine shipping.

The president also instructed the Defense Department to develop plans to disable, in certain areas, an enemys access to the U.S. navigational satellites and to similar systems operated by others. The European Union is developing a $4.8 billion satellite navigation program called Galileo.

'Clearly a big deal'
The military increasingly uses GPS technology to move troops across large areas and direct bombs and missiles. Any government-ordered shutdown or jamming of the GPS satellites would be done in ways to limit disruptions to navigation and related systems outside the affected area, the White House said.

This is not something you would do lightly, said James A. Lewis, director of technology policy for the Washington-based Center for Strategic and International Studies. Its clearly a big deal. You have to give them credit for being so open about what theyre going to do.

GPS is based on a constellation of 24 solar-powered orbital satellites about 12,000 miles above the Earth. A GPS receiver on the ground seeks tracking signals from at least three satellites, then interpolates the data to establish latitude and longitude. If a device can pick up four or more signals, it can also determine a user's altitude.

The U.S. military originally built NAVSTAR, as they called it. The first satellite was launched in 1978 and the system was fully operational by the early 1990s. Originally, the military programmed the system for "selective availability," which gave the military 10-meter precision and civilians 100-meter precision. Selective availability was eliminated in 2000.

Users can get accurate location information across the globe, and most equipment can interpret it to provide speed, distance to a destination and even exact local sunrise and sunset times. Devices are installed in most large ships and aircraft, and the FAA has incorporated GPS as a key part of instrument flight. Many cars use it, and transit companies use it to track trucks and buses. Handheld devices are used by everyone from hikers to land surveyors. The military has adapted bombs with GPS receivers that can guide the weapons to targets.

With the military controls removed, GPS users can now get a precise latitude and longitude to within 10 to 15 meters. Advanced systems known as differential GPS and the Wide Area Augmentation System incorporate the use of stationary ground stations to interpolate signals, and can offer accuracy of 1 to 3 meters or better. The satellites have diagnostic systems and stop sending position data if they're malfunctioning.

The U.S. Department of Defense continues to run the system, though other federal agencies such as the Department of Transportation have taken a role in upgrading and maintaining it. The Coast Guard helps maintain the civilian portions of the system, and private satellite operators provide signals for some advanced interpolation services. The government's Interagency GPS Executive Board coordinates efforts.

President Clinton abandoned the practice in May 2000 of deliberately degrading the accuracy of civilian navigation signals, a technique known as selective availability.

The White House said it will not reinstate that practice, but said the president could decide to disable parts of the network for national security purposes.

Part of space policy
The directives to the Defense Department and the Homeland Security Department were part of a space policy that Bush signed this month. It designates the GPS network as a critical infrastructure for the U.S. government. Part of the new policy is classified; other parts were disclosed Wednesday.

The White House said the policies were aimed at improving the stability and performance of the U.S. navigation system, which Bush pledged will continue to be made available for free.

The U.S. network comprises more than two dozen satellites that act as beacons, sending location-specific radio signals that are recognized by devices popular with motorists, hikers, pilots and sailors.

Bush also said the government will make the network signals more resistant to deliberate or inadvertent jamming.

© 2004 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
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White House Wants Plans For GPS Shutdown

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