[ntp:questions] GPS Jammers in Use by Criminals - Warping Time for Fraud Suggested
david at ex.djwhome.demon.invalid
Thu Feb 23 08:05:50 UTC 2012
Chris Albertson wrote:
> That depends on the time scale. Over all it is wide because they have
> to allow for all the doppler shifts but at any one instant in time a
> spread spectrum is a narrow band radio.
It is direct sequence, not frequency hopping. I think the spread
spectrum is more to do with interference rejection and coding gains.
The significance of Doppler is that it rules out frequency division
multiplexing. For the L2 signal, it is also a question that the
chipping code is cryptographic. The chipping codes for L1 are
published, so a consumer GPS signal could be completely spoofed.
> My main point was that it should be easy to find an unsophisticated
> jammer. You might even place detectors where they can trigger
> existing red-light enforcement cameras
I think the news items originate from press releases about a study that
involved installing a network of jammer detectors and suggesting the
best places to put them (although only really in relation to stolen
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