[ntp:questions] GPS Jammers in Use by Criminals - Warping Time for Fraud Suggested

Charles Elliott elliott.ch at verizon.net
Fri Feb 24 03:51:57 UTC 2012


The reason electric generators join the system at the proper frequency
is because the system will rip a generator out of its moorings if it is
rotating 
too fast or too slow.  There is much more energy in the system as conveyed
by a high 
power transmission line than there is in a single generator.
Frequency synchronization is a defensive measure. It is all done with meters
at
the tie-line point or with readings telemetered to a central control center.

Charles Elliott

> -----Original Message-----
> From: questions-bounces+elliott.ch=verizon.net at lists.ntp.org
> [mailto:questions-bounces+elliott.ch=verizon.net at lists.ntp.org] On
> Behalf Of unruh
> Sent: Thursday, February 23, 2012 4:41 PM
> To: questions at lists.ntp.org
> Subject: Re: [ntp:questions] GPS Jammers in Use by Criminals - Warping
> Time for Fraud Suggested
> 
> On 2012-02-23, Richard B. Gilbert <rgilbert88 at comcast.net> wrote:
> > On 2/22/2012 5:16 PM, David Woolley wrote:
> >> An article in the Metro, the free morning paper on the London
> >> commuter transport network, suggests that criminals may be using GPS
> >> jamming equipment to warp the time on financial systems to allow the
> >> commission of fraud.
> >>
> > GPS is not the only source of time!
> >
> > In the U.S. 60 cycle Alternating Current is the standard and the
> > source of time.  It's not going to give you the nanoseconds but very
> > few people could even explain what a nanosecond is let alone needing
> > nanosecond resolution.
> 
> It is neither a standard nor is it a "source of time". The requirement
> is that the phase of the 60Hz be the same across the country, so
> electricity can be traded between generation facilities without one
> source shorting out the other. That does not require frequency
> accuracy, just that the frequency of all the generators be the same and
> the phase difference be less than  a ms or so.
> 
> Because the easiest way to ensure phase coherence is to demand
> frequency coherence and use a standard, like UTC, as a reference, they
> do tend to be close. But the requirement is phase coherence not time
> accuracy and the latter will be jettisoned in favour of the former.
> 
> >
> >> Although I can't find the source of that article, the BBC has an
> >> article, presumably from the same underlying source, addressing
> >> another point in that that article, that GPS jammers are
> increasingly
> >> being used to defeat GPS based car tracking systems.
> >
> > If anyone wants to track my car's location, you're welcome.  And I
> > hope that no one dies of boredom!
> >
> ><snip>
> 
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