The Global Positioning System (GPS), the space network that helps aircraft, ships and explorers to navigate, can be jammed using cheap equipment bought from stores and knowledge acquired on the Internet, New Scientist says.
A US Air Force Team dubbed the Space Aggressor Squadron was set up to look for weak spots in satellite communications and navigation systems, the British scientific weekly says in next Saturday's issue.
Playing the part of a potential enemy, two rookie engineers were able to build a satellite jammer by downloading information from the Internet and purchasing equipment from home improvement stores and electronics "swap meets."
For only 7,500 dollars, they built a device using a UHF signal amplifier and noise generator, copper tubing which acted as an aerial, with desultory pieces of wood and plastic piping. A petrol-driven electricity generator provided the power.
Loaded into a pickup truck, the device was "an effective mobile jammer," capable of blocking satellite antennas or military UHF receivers, it says.
"Different components could be used to jam other frequencies, such as that of the Global Positioning System," it adds.
The GPS uses signals from several satellites in an orbiting constellation to triangulate a position, with accuracy down to a few meters.
It is so becoming so prevalent that there are now GPS systems being incorporated in top-of-the-range cars, as well as GPS wristwatches.
John Pike, director of space policy at the Federation of American Scientists, told the magazine that it was "simple" to jam the GPS, because the satellite signal is weak.
But he believed that the latest generation of global communications satellites would be immune to similar home-built equipment, as they are "heroically resistant to jamming." -- PARIS (AFP)
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