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The fleet of satellites that makes up the Global Positioning System (GPS)
could be a tempting target for enemies of the US, says a Department of
Transportation report. While the military is aware of the risks, civilian
aircraft, ships and cars often are not. GPS could be damaged via physical attack
on its satellites or electronic jamming, so users need to have access to
anti-jamming technologies and back-ups for critical systems. 鈥淭he GPS system
cannot serve as the sole source for position location or precision timing for
certain critical applications,鈥� says the report.