The San Diego Union-Tribune June 10, 2004
GPS signals jammed by military
Some worry about people getting lost
By James W. Crawley
The Pentagon is jamming GPS signals -- which are used by pilots, drivers and hikers to navigate -- in parts of Alaska during a military exercise this week, a move that has some pilots and backcountry tourism officials worried about people getting lost.
GPS, which stands for global-positioning system, uses satellites to pinpoint a person's location to within a few feet and has largely supplanted the compass. The military, which devised and operates the system, uses GPS to navigate planes and tanks and to drop bombs with unprecedented accuracy.
Worried that enemies can jam or interfere with those signals, the military has set up GPS jamming transmitters in Alaska to test anti-jamming equipment.
The tests are part of a larger annual military exercise that involves Navy and Marine Corps aircraft from San Diego, along with the aircraft carrier John C. Stennis and its escorts. The exercise, called Northern Edge 2004, ends June 16.
The Air Force will operate two jammers near Fairbanks through tomorrow, switching them on for short periods each day. The affected area covers hundreds of square miles, including recreational areas used by hikers and campers. Several civilian airstrips are nearby.
A military spokesman said the jamming exercise shouldn't worry pilots or hikers.
"As long as civilian fliers aren't in (exercise) range airspace, there should be little or no impact. There is little or no impact on people on the ground," said Air Force Maj. Brenda Campbell.
But a representative of a national pilots' group said GPS jamming and outages are worrisome because many pilots don't get adequate warning.
"It's a big issue to those affected by it. But it's not a big issue geographically," said Jeff Myers, executive vice president of the Aircraft Owners and Pilots Association.
GPS has become commonplace in cars, boats, planes and hikers' backpacks. Many new cell phones incorporate GPS chips that can instantly signal a caller's location to emergency dispatchers.
But since it uses faint radio signals from high-flying satellites, GPS can easily be disrupted and cause incorrect positions to be displayed.
The military is worried about jamming because so many of its high-tech weapons -- from stealth bombers to armored vehicles and satellite-guided bombs -- depend on GPS for navigation and accuracy. In last year's invasion of Iraq, there was some scattered jamming, but it had little impact on combat.
The Pentagon has spent millions on anti-jamming technology, said John Pike, a defense analyst.
"They have to test it in the field" to see that it works, said Pike, director of GlobalSecurity.org, an independent think tank in Virginia. "You can't rely on computer simulations."
However, with the ubiquitous nature of GPS receivers, Pike said any jamming might have unanticipated consequences for civilian users.
"Anybody relying on GPS shouldn't rely on it" while the military is jamming, he said. "If I was out hiking or flying in Alaska, I wouldn't want to be without GPS."
Ann Gore, who represents backcountry tourist guides and outfitters in Alaska, said her members were unaware the military would be jamming GPS signals.
"GPS is used frequently and is quite important in backcountry Alaska, particularly for backcountry pilots," said Gore, executive director of the Alaska Wilderness Recreation and Tourism Association.
In all, about 3,500 area Marines and sailors will participate in Northern Edge 2004.
Jets from the Stennis will fly overland bombing missions. The Stennis is accompanied by the San Diego-based cruiser Lake Champlain and destroyer Howard. The Stennis and its escorts left San Diego last month for a routine Western Pacific deployment. After Northern Edge, the carrier strike group will participate next month in the biennial Rim of the Pacific war game off Hawaii.
Also flying missions in Alaska this week is Marine Corps squadron VMFA-225 from Miramar Marine Corps Air Station. The unit has been deployed to Japan for several months.
© Copyright 2004, The San Diego Union-Tribune
