On 10/09/2010 09:47 PM, jimlux wrote:
Bob Camp wrote:
Hi
The Russians have been willing to sell GPS jammers for quite a while.
They aren't terribly expensive. Their export controls are a bit
different than the US's.
Bob
Simple GPS jammers are pretty easy, since consumer GPS is very
vulnerable to repeater jammers. Hmm I wonder if that would adversely
affect a GPSDO? Probably not, since the repeated signal is just as
stable as the original one.
Well, a real jammer will just prohibit the reception of signal while a
spoofing attempt would provide a false signal. There is no reason to
assume that a spoofed signal would be stable. Also, the spoofing attempt
we talked about through the WAAS bent-pipe does not necessarily make the
GPS receiver lock onto all the spoofed signals, but a shifting selection
of correct and spoofed signals. RAIM in receivers would help to some
degree, If it fully locks on to the spoofing signal, just to be thrown
away in time and that should upset most GPSDOs quite a bit.
jammers probably aren't subject to export controls, just local usage
regulations (e.g. illegal in US because of FCC rules prohibiting them).
the ITAR (which is the big deal in the export controls world, compared
to EAR) is the *International* Tariff, so everyone is a signatory, and
we're all in the same boat as to what is a munition and what is not.
Granted, enforcement and interpretation varies.
Someone seriously wanting to use one for some reason would not care
significantly and found ways around it. Someone with sufficient
knowledge would build one if needing to.
Cheers,
Magnus
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