Just a word to the wise,
How to prevent dangerous, easy GPS jamming
WASHINGTON -- It took engineers at Newark airport two months to figure out why a new navigation aid went on the blink twice a day. They eventually discovered the cause: a passing truck driver using a cheap GPS jammer to cheat tolls on the New Jersey Turnpike.
That was in 2009.
Two years earlier, the U.S. Navy jammed GPS reception as part of a military readiness exercise off the Southern California coast.
NewScientist.com describes the chaotic two hour disruption to air traffic controllers' monitors, failure of doctors' emergency pagers, ATMs refusing to dispense cash, confused maritime traffic management and a cell phone blackout.
GPS systems do more than tell us where to turn. That's why jamming them is so dangerous.
GPS signals are easy to jam because they are so weak. Satellites send the low-power, line-of-sight signals from more than 12,000 miles away. NASA calls them "equivalent to a Los Angeles user receiving the light from a 60 watt light bulb in New York."
NASA prepared a white paper last November, laying out its assessment of the threat along with recommendations for coping with it.
They include:
•A recommendation that the president formally declare GPS "critical infrastructure," and assign its management to the Department of Homeland Security.
•A national network for alerting and pinpointing interference.
•Congressional legislation addressing GPS interference "that provides substantial fines and jail time for both possession and use of GPS jammers."
•Hardening GPS receivers and antennas.
•Funding a back-up system capable that will "insure continuity" of GPS operations.
A back-up system does - or did - exist and was used before GPS became standard.
Before satellite navigation existed, e-Loran, a less fragile ground-based radio-navigation, was used extensively and successfully.
The cost of maintaining a ground-based system would be around $20 million a year, according to an Institute for Defense Analysis study.
Although the general public has had little awareness of GPS jamming, federal security agencies have been thinking about it long and hard.
The Defense Advanced Research Projects Agency has floated a plausible fix to the puzzle of how jammers could be located.
DARPA proposes creating free smart phone apps that can detect GPS jammers, and that the public be asked to download them and always leave them on, The Economist reports.
Widespread use of the app would create a high-density detection network that could pinpoint jammers quickly.
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