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

[Uwe Klein]

David Woolley wrote:

Jason wrote:


So, what would be a characteristic symptom or tell-tale of jamming?

Simple jamming, as used to defeat vehicle tracking, would result in the 
loss of all satellites.  Sophisticated jamming, to produce a false time, 
would, for its target, produce a slow drift in the time, with no alarms, 
although the signal strength would be higher than usual.  Receivers at 
the limits of jammer range might not be able to get consistent solutions 
across different satellite combinations, so might alarm for that, and 
otherwise might behave as for a simple jammer.


What kind of deviations (type, magnitude) can I introduce via
spoofing WAAS or EGNOS transmissions ?

uwe

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

[David Woolley]

Jason wrote:


So, what would be a characteristic symptom or tell-tale of jamming?

Simple jamming, as used to defeat vehicle tracking, would result in the 
loss of all satellites.  Sophisticated jamming, to produce a false time, 
would, for its target, produce a slow drift in the time, with no alarms, 
although the signal strength would be higher than usual.  Receivers at 
the limits of jammer range might not be able to get consistent solutions 
across different satellite combinations, so might alarm for that, and 
otherwise might behave as for a simple jammer.


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

[Jason]

On 22-Feb-12 17:28, Chris Albertson wrote:

Should be easy to build a hand held jammer detector with a directional
antenna that the user can sweep around.Or they can put the
detector at the car ferry toll both.In theory jammer detectors
could be cheaper to build than GPS receivers.

Could you make one at home.  I think all that is needed is a long
directional antenna.  Maybe a helix type, an RF amplifier, filter and
a RF power meter.

My guess is these jammers are not very sophisticated and simply blast
RF hash all over L1 and adjacent bands.   A sophisticated jammer would
know exactly when to transmit over one bit or two bits, and in a
narrow band just enough to corrupt the GPS data and would have a very
lower average power output.  That would be hard to detect

I'd bet these jammers are the simplest type that can still work.



On Wed, Feb 22, 2012 at 2:16 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.

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.

http://www.bbc.co.uk/news/technology-17119768

The Metro mentions a risk to car ferries from the denial of navigation data.

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So, what would be a characteristic symptom or tell-tale of jamming?

Consider a receiver that is connected to an NTP server, which receives 
the NMEA strings and PPS from the receiver? Would the server report loss 
of NMEA strings and/or loss of PPS? I know that would be dependent on 
the particular manufacturer, but would you expect that behavior as being 
a reasonable implementation, or something else?


Consider the hypothetical case of the delivery driver that is jamming 
the GPS receiver in his van to block his company from tracking the 
vehicle, 'cause he's napping along the way and blaming the delay on 
"traffic jam".


Would you expect two (or more?) similar but from different manufacturer 
devices/servers, located, say, in one large building, or adjacent 
buildings, to experience similar loss of signal at the same (or nearly 
so) time?


In another scenario, consider sequential deliveries by the same tired 
delivery driver: If the delivery truck (with a jammer to block vehicle 
tracking) visiting two adjacent buildings, would you expect one receiver 
to get wonky (highly technical term)(presumably the closest to the 
source) and recover after a few minutes , followed within a minute or so 
later, by the receiver in the next building going wonky? This might be a 
scenario where a delivery truck is stopping at building one's dock, 
making a delivery, then moving to the next building's dock and doing the 
same.


With a pattern of disruptions, and by correlation of time of disruption 
with delivery logs, I would expect that you'd be able to ascertain if, 
indeed, there is a delivery van with a jammer.


But, what if the times are more random, and or outside what would be 
'normal' delivery times. Or of very short duration (such as the jammer 
driving by on the street outside the building).


Further, if two servers lost NMEA and PPS from two different antenna and 
receivers, nearly instantaneously. Would you consider that evidence of 
purposeful jamming? Would it be unintentional if it were very short (the 
nefarious tired delivery driver just driving by on his route).


What else might convince you that your receivers were being jammed?

Jason.

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

[Dave Hart]

On Fri, Feb 24, 2012 at 00:23, John Hasler  wrote:
> Dave Hart writes:
>> Given the dwinding number of such clocks and relatively arcane grid
>> operational reasons, there's been some movement to abandon the
>> corrections, which seems to be stalled at the moment.
>
> I thought that they had already decided to go ahead with it.

The original AP article which brought the proposed "toss the time
error corrections to frequency" experiment to light referred to it
only as a proposal.  Given the level of bureaucracy involved in
coordinating power grids, I can't imagine how you read that as a done
deal.

That same story also quoted the heads of both NIST and USNO
timekeeping saying there would be widespread effects.

I stand by my "seems to be stalled at the moment" assessment.

Cheers,
Dave Hart
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Re: [ntp:questions] GPS Jammers in Use by Criminals - Warping Time for Fraud Suggested

[David J Taylor]

"unruh"  wrote in message 
news:viy1r.9526$1i2.3...@newsfe08.iad...
On 2012-02-23, j...@specsol.spam.sux.com  
wrote:

Richard B. Gilbert  wrote:

[]
There are very few civilian systems where absolute time accuracy 
greater
than 1 second is an operational requirement and none that I can think 
of
where sub-microsecond absolute time accuracy is an operational 
requirement.


Long baseline radio astronomy? Timing neutrinos between Cern and Grand
Sasso? ...
Both are civilian, and both absolutely require nano second accuracy.


.. but both are "research" and not "operational".  On the other hand, GPS 
is both operational and sub-microsecond.


Cheers,
David 


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

[Charles Elliott]

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@lists.ntp.org
> [mailto:questions-bounces+elliott.ch=verizon@lists.ntp.org] On
> Behalf Of unruh
> Sent: Thursday, February 23, 2012 4:41 PM
> To: questions@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  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!
> >
> >
> 
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Re: [ntp:questions] GPS Jammers in Use by Criminals - Warping Time for Fraud Suggested

[John Hasler]

Dave Hart writes:
> Given the dwinding number of such clocks and relatively arcane grid
> operational reasons, there's been some movement to abandon the
> corrections, which seems to be stalled at the moment.

I thought that they had already decided to go ahead with it.

> 

Thus we see that a political blogger can turn even the most arcane
techical matter into an attack on the opposition.
-- 
John Hasler 
jhas...@newsguy.com
Dancing Horse Hill
Elmwood, WI USA

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

[John Hasler]

David Woolley writes:
> I believe that, in the UK, only the long term timing has ever been
> guaranteed.  The frequency goes down at peak load and is increased at
> other times, to compensate.

That was true in the USA as well, but with grids getting larger and the
number and types of sources increasing the compensation was getting
harder and harder to do while maintaining stbility.  Since the grid is
no longer an important source of time they relaxed the limit on
accummulated phase error.  Slashdot was full of cries of doom.
-- 
John Hasler 
jhas...@newsguy.com
Dancing Horse Hill
Elmwood, WI USA

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

[jimp]

Rick Jones  wrote:
> Richard B. Gilbert  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.
> 
> Wasn't there something about an experiment to relax the frequency
> requirements on the power grid in North America?  And the financial
> services types may not be at the nanosecond level, but they (think
> they) are at the microsecond level.
> 
> rick jones

The absolute frequency accuracy in the US has never been anywhere close to
the microsecond level.

What was guaranteed was the long term average would be 60 Hz so things
like clocks with synchronous motors would be within a few seconds over
day long periods.


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

[David Woolley]

Richard B. Gilbert wrote:




GPS is not the only source of time!



My impression is that the sort of organisation that has lots of money to 
spend, has management with arts degrees, and from which large amounts of 
money can be extracted by changing the apparent order of events, tend to 
prefer GPS.  Organisations with less money and significant timing 
requirements, will try to use over the wire NTP.


My understanding is the important thing in time based fraud is to be 
able re-arrange apparent cause and effect.


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

[David Woolley]

Rick Jones wrote:



Wasn't there something about an experiment to relax the frequency
requirements on the power grid in North America?  And the financial



I believe that, in the UK, only the long term timing has ever been 
guaranteed.  The frequency goes down at peak load and is increased at 
other times, to compensate.


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

[Rick Jones]

Richard B. Gilbert  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.

Wasn't there something about an experiment to relax the frequency
requirements on the power grid in North America?  And the financial
services types may not be at the nanosecond level, but they (think
they) are at the microsecond level.

rick jones
-- 
denial, anger, bargaining, depression, acceptance, rebirth...
 where do you want to be today?
these opinions are mine, all mine; HP might not want them anyway... :)
feel free to post, OR email to rick.jones2 in hp.com  but NOT BOTH...

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

[Dave Hart]

On Thu, Feb 23, 2012 at 21:40, unruh  wrote:
> On 2012-02-23, Richard B. Gilbert  wrote:
>> 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 sounds a bit oversimplified.  In the US, there are three
different grids, with some DC interconnections.

> 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.

Load skews frequency, and each grid's frequency runs a bit slow during
peak load times.  The generators do not sync to 60 Hz, they sync to a
nearby value that is the grid frequency at any instant.

> But the requirement is phase coherence not time accuracy and
> the latter will be jettisoned in favour of the former.

Yes but only to a limited extent, so far.  Because of the prevalence
of clocks that do rely on the grid for timekeeping, each day the
frequency is intentionally boosted on each of the 3 US grids during
non-peak periods to compensate for the missing cycles from the
load-induced slowdown.  At the end of the day the total number of
cycles should be near nominal, insulating such clocks from
accumulating offsets day to day due to the interaction of AC generator
load and frequency.  Given the dwinding number of such clocks and
relatively arcane grid operational reasons, there's been some movement
to abandon the corrections, which seems to be stalled at the moment.

http://www.treehugger.com/corporate-responsibility/clocks-may-drift-while-us-power-grid-adapts-to-increased-use-of-renewable-energy.html

Cheers,
Dave Hart
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Re: [ntp:questions] GPS Jammers in Use by Criminals - Warping Time for Fraud Suggested

[unruh]

On 2012-02-23, Richard B. Gilbert  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!
>
>

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

[unruh]

On 2012-02-23, j...@specsol.spam.sux.com  wrote:
> Richard B. Gilbert  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.
>
> There are very few civilian systems where absolute time accuracy greater
> than 1 second is an operational requirement and none that I can think of
> where sub-microsecond absolute time accuracy is an operational requirement.

Long baseline radio astronomy? Timing neutrinos between Cern and Grand
Sasso? ...
Both are civilian, and both absolutely require nano second accuracy. 

>
>>> 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!
>
> In this case what is being jammed is position, not time, and this is so
> smarter car thieves can defeat systems like LoJack.
>
> This is a much easier case as all that has to be jammed is the GPS in the
> car being stolen.
>
>

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

[unruh]

On 2012-02-23, Richard B. Gilbert  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.
>
>> 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!

If you are a policeman who has installed a gps tracker on a criminal or
terrorists car, that jamming is a problem. If you are company owner
whose truck drivers are suspected of abandoning their trucks for an hour
or so to visit some well known ladies, that could be a problem. If you
put a gps tracker on you car to recover it if it gets stolen, that could
be a problem. If your car has something like OnStar, and you get into an
accident from which you would like help to be rescued, that jamming
could be a problem. 

>
>

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

[jimp]

E-Mail Sent to this address will be added to the BlackLists 
 wrote:
> j...@specsol.spam.sux.com wrote:
>> In this case what is being jammed is position, not time,
>>  and this is so smarter car thieves can defeat systems like LoJack.
>>
>> This is a much easier case as all that has to be jammed
>>  is the GPS in the car being stolen.
> 
> LoJack is a radio beacon, it transmits a ID#,
> but no location information.
> 

Well, I did say "systems LIKE LoJack", but if you want to be anal about it,
how about "systems like OnStar" which do send location information?


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

[Chris Albertson]

On Thu, Feb 23, 2012 at 11:31 AM, Richard B. Gilbert
 wrote:

>>
> GPS is not the only source of time!
>
> In the U.S. 60 cycle Alternating Current is the standard and the source of 
> time.

No.  It is not the "standard"  It is at best a "commonalty used
frequency source".   Absolute time is not transmitted on the power
lines.  But in recent years I wonder even about "commonalty used"
most cheap clocks use crystals now.

The US standard is at NIST.


Chris Albertson
Redondo Beach, California
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Re: [ntp:questions] GPS Jammers in Use by Criminals - Warping Time for Fraud Suggested

[E-Mail Sent to this address will be added to the BlackLists]

j...@specsol.spam.sux.com wrote:
> In this case what is being jammed is position, not time,
>  and this is so smarter car thieves can defeat systems like LoJack.
>
> This is a much easier case as all that has to be jammed
>  is the GPS in the car being stolen.

LoJack is a radio beacon, it transmits a ID#,
 but no location information.

-- 
E-Mail Sent to this address 
  will be added to the BlackLists.

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

[Chuck Swiger]

On Feb 23, 2012, at 11:30 AM, Richard B. Gilbert 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!

Certainly true.  ACTS phone dialup, NIST WWB/WWVB broadcasts in the USA, DCF77 
in Europe, etc are other sources 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.


In the US, the electric grid is supposed to be kept to within 10 seconds:

  
http://en.wikipedia.org/wiki/Utility_frequency#Long-term_stability_and_clock_synchronization

There are maps and tables showing the frequency corrections world-wide and for 
the US here (although some of the tables claim to be using sample data and not 
realtime measurements):

  http://fnetpublic.utk.edu/index.html

Regards,
-- 
-Chuck

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

[jimp]

Richard B. Gilbert  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.

There are very few civilian systems where absolute time accuracy greater
than 1 second is an operational requirement and none that I can think of
where sub-microsecond absolute time accuracy is an operational requirement.

>> 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!

In this case what is being jammed is position, not time, and this is so
smarter car thieves can defeat systems like LoJack.

This is a much easier case as all that has to be jammed is the GPS in the
car being stolen.


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

[Richard B. Gilbert]

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.



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!




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

[Richard B. Gilbert]

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.



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!




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

[David Woolley]

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 
vehicles).


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

[Chris Albertson]

On Wed, Feb 22, 2012 at 6:01 PM, John Hasler  wrote:
> Chris writes:
>> A sophisticated jammer would know exactly when to transmit over one
>> bit or two bits, and in a narrow band just enough to corrupt the GPS
>> data and would have a very lower average power output.
>
> That would be a very sophisticated jammer indeed.  GPS is not narrow
> band.  It's spread-spectrum.

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.

You are correct that spoofing is harder.  But there is an example of a
really excellent GPS spoof in Iran.

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

> Spoofing it is much, much harder than
> jamming it (though not impossible for simple consumer-grade receivers).
>
> BTW jamming won't do a bit of good for the "time warping" fraud
> suggested.
> --
> John Hasler
> jhas...@newsguy.com
> Dancing Horse Hill
> Elmwood, WI USA
>
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-- 

Chris Albertson
Redondo Beach, California
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Re: [ntp:questions] GPS Jammers in Use by Criminals - Warping Time for Fraud Suggested

[John Hasler]

Chris writes:
> A sophisticated jammer would know exactly when to transmit over one
> bit or two bits, and in a narrow band just enough to corrupt the GPS
> data and would have a very lower average power output.

That would be a very sophisticated jammer indeed.  GPS is not narrow
band.  It's spread-spectrum.  Spoofing it is much, much harder than
jamming it (though not impossible for simple consumer-grade receivers).

BTW jamming won't do a bit of good for the "time warping" fraud
suggested.
-- 
John Hasler 
jhas...@newsguy.com
Dancing Horse Hill
Elmwood, WI USA

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

[Joe Wulf]

Methinks you'll see more observations, impacts and new/media reporting of such 
instances as the criminals continue to criminally exploit and adversely affect 
our world.

I'm glad to see you use the proper term 'criminal' for such miscreants, vice 
the good name of 'hacker'.   





>
> From: David Woolley 
>To: questions@lists.ntp.org 
>Sent: Wednesday, February 22, 2012 5:16 PM
>Subject: [ntp:questions] GPS Jammers in Use by Criminals - Warping Time for 
>Fraud Suggested
> 
>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.
>
>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.
>
>http://www.bbc.co.uk/news/technology-17119768
>
>The Metro mentions a risk to car ferries from the denial of navigation data.
>
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Re: [ntp:questions] GPS Jammers in Use by Criminals - Warping Time for Fraud Suggested

[Chris Albertson]

Should be easy to build a hand held jammer detector with a directional
antenna that the user can sweep around.Or they can put the
detector at the car ferry toll both.In theory jammer detectors
could be cheaper to build than GPS receivers.

Could you make one at home.  I think all that is needed is a long
directional antenna.  Maybe a helix type, an RF amplifier, filter and
a RF power meter.

My guess is these jammers are not very sophisticated and simply blast
RF hash all over L1 and adjacent bands.   A sophisticated jammer would
know exactly when to transmit over one bit or two bits, and in a
narrow band just enough to corrupt the GPS data and would have a very
lower average power output.  That would be hard to detect

I'd bet these jammers are the simplest type that can still work.



On Wed, Feb 22, 2012 at 2:16 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.
>
> 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.
>
> http://www.bbc.co.uk/news/technology-17119768
>
> The Metro mentions a risk to car ferries from the denial of navigation data.
>
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> questions mailing list
> questions@lists.ntp.org
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-- 

Chris Albertson
Redondo Beach, California
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[ntp:questions] GPS Jammers in Use by Criminals - Warping Time for Fraud Suggested

[David Woolley]

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.


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.


http://www.bbc.co.uk/news/technology-17119768

The Metro mentions a risk to car ferries from the denial of navigation data.

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