On Sun, May 21, 2000 at 01:07:11PM -0700, Phil Karn wrote:
Sounds like some interested parties should take some GPS gear and some
radio receiving and test gear to one of the spots where the millatree
is warning airmen that "for the next two weeks, GPS doesn't work
here", and see just what
This makes it quite possible to detect this kind of simple
spoofing by using two or more GPS antennas located a known distance from
each other and checking to see that the positions computed from the
signal out of each one differ by the known distances.
Sounds like some interested
Thanks to all for the very interesting info. For people interested, here's
a summary of answers and ideas:
The generally (not-US military) available C/A signal is not protected as
far as people know; in fact it seems it may be jammed rather easily,
where jamming may even mean spoofing
If I were worried about integrity of timing signals, I'd use a
GPS-disciplined rubidium oscillator. I think most of the available
devices like this are not quite as concerned with integrity as phase
noise reduction in the normal case, so some tweaking of the
These are actually quite common in
To decrease the jamming power required (this -is- spread spectrum,
after all), it's helpful to have your jammer hop the same way your
receiver will be hopping. This is pretty easy to do, since your
jammer can trivially figure out the hops by observing the satellites
you can see. Note also that
Date: Thu, 11 May 2000 11:01:08 -0700
From: Phil Karn [EMAIL PROTECTED]
[ . . . ] No need to observe the satellites you're jamming.
Yes. I was careless with my phrasing. What I meant was, "the
satellites that you care to impersonate, which are presumably the ones
that the victim
Date: Thu, 11 May 2000 11:01:08 -0700
From: Phil Karn [EMAIL PROTECTED]
In many ways, a GPS spoofer is a much simpler device than a GPS
receiver.
Very much agreed. It's also the case that some receivers manage to
jam others near them; it's especially common w/cheapo receivers
At 12:43 PM +0300 5/11/2000, [EMAIL PROTECTED] wrote:
Thanks to all for the very interesting info. For people interested, here's
a summary of answers and ideas:
You left out my direction finding approach :( I think it has merit.
Electronically steerable antennas are quite practical at L band
A company called Certified Time offers secure NIST-based time data and has
many unkind things to say about the integrity of GPS time signals. You
might find some useful references among the documents they have posted at
http://www.certifiedtime.com/site/repository/index.html
At 09:24 AM 5/8/00
Lenny Foner [EMAIL PROTECTED] writes:
As for corrupting the signal, I think that would require a bit more
work, but I personally think it could be done. I don't think there is
any kind of cryptographic integrity protection of GPS signals.
Not correct. (And finally relevant to
) and suspect it doesn't exist anymore. In any case, based on
what I've read in Denning's article, I think SmartLocator does not claim to
secure GPS integrity. SmartLocator claims to provide a `location signature`
using GPS, that is, a way to prove that the sender of a message has a GPS
receiver
to
Denning's note) and suspect it doesn't exist anymore. In any case, based on
what I've read in Denning's article, I think SmartLocator does not claim to
secure GPS integrity. SmartLocator claims to provide a `location signature`
using GPS, that is, a way to prove that the sender of a message has a GPS
Dorothy Denning wrote an interesting paper on authenticating location using
GPS signals... I think it's reachable from her home page as well as the
following citation:
D. E. Denning and P. F. MacDoran, "Location-Based Authentication: Grounding
Cyberspace for Better Security," Computer Fraud and
ound 1996; I haven't found any more info about it (further to
Denning's note) and suspect it doesn't exist anymore. In any case, based on
what I've read in Denning's article, I think SmartLocator does not claim to
secure GPS integrity. SmartLocator claims to provide a `location signature`
using GPS, tha
Dorothy Denning wrote an interesting paper on authenticating location using
GPS signals... I think it's reachable from her home page as well as the
following citation:
D. E. Denning and P. F. MacDoran, "Location-Based Authentication: Grounding
Cyberspace for Better Security," Computer Fraud
I presume the paper in question is
http://www.cs.georgetown.edu/~denning/infosec/Grounding.txt
Ian BROWN writes:
Dorothy Denning wrote an interesting paper on authenticating location using
GPS signals... I think it's reachable from her home page as well as the
following citation:
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