[time-nuts] GPS Spoofing

Bob Camp lists at rtty.us
Sun Jul 28 13:12:35 EDT 2013


Hi

I'm not talking about taking out Loran-C over the entire North Atlantic. The target is a harbor sized area. For that, you certainly do not need a 600' antenna or megawatts of power. You only need to generate a near field signal, not set up something that will propagate beyond line of sight. There are a couple of ways that the antenna could be done. 

Long term, Loran-C is reasonably stable *if* the propagation is over water. If it's over land (as with most of the US chains) it's not as stable. A bit of drift from time to time was indeed very much expected. Great for getting back to last month's fishing spot, not quite so great for getting back to one from many years ago. 

Bob

On Jul 28, 2013, at 1:00 PM, "Poul-Henning Kamp" <phk at phk.freebsd.dk> wrote:

> In message <26BB6F2A-69AC-4587-8057-BA18A03E8A6B at rtty.us>, Bob Camp writes:
> 
>> Bumping it a bit this way or that is not an impossibility. A little
>> bit of  added phase this way or that is all it would take. You would have 
>> to get the rep rate and timing right, but that's just the sort of thing a
>> Time Nut knows how to do on the cheap. 
> 
> Only its not actually possible in practice.
> 
> The problem with GNSS is that the kit to jam/spoof is sub-suitcase-sized.
> 
> To jam/spoof LORAN-C or any other VLF system, you need several
> trucks: One for the generator, one for the antenna -- at least.
> 
> That's the reason why LORSTA's have 600' antenna towers to begin with.
> 
> LORAN-C may not be as precise, but it is very stable, which means
> that your dual-source nav-kit will tell you that GPS and LORAN-C
> diverges in ways that looks odd...
> 
> The reason why we still have LORAN-C in europe, is that UK and
> France don't trust DoD to not play with GPS.
> 
> -- 
> Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
> phk at FreeBSD.ORG         | TCP/IP since RFC 956
> FreeBSD committer       | BSD since 4.3-tahoe    
> Never attribute to malice what can adequately be explained by incompetence.



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