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    Re: GPS "spoofing"
    From: Frank Reed
    Date: 2013 Jul 27, 08:58 -0700

    Geoffrey, you wrote:
    "A couple of years ago, I was at a defense exhibition in London and was one of a party being shown around a large British warship. I asked about the vulnerability of the GPS navigation system to 'spoofing'. The reply was unusually candid. Just a few months previously, the ship has been subjected to an intense effort to jam or spoof the GPS navigation system in order to test the vulnerability of such systems to such attacks. The worst these attacks did was to move the ship (virtually) eight feet....."

    It has been my understanding that it is much harder to spoof military GPS systems. They have clever redundancies and consistency checks. But a standard non-redundant civilian system should be pretty easy to spoof, just as the article says. Of course, this has been known for quite a few years. The difference now is that we have media coverage of an actual test case.

    There are some details worth knowing regarding this test case:
    --Where was the spoofing system located? On the vessel? How far away can it be and still be effective?
    --Did the vessel have any other GNSS systems on-board? Were handheld GPS systems affected, too, or just the main navigation system? Did they have GLONASS capability, too? Was that also spoofed?
    --Would a system capable of of both GPS and GLONASS positioning have issued any kind of warning? Or would it just fall back to the strongest signals (probably the spoofed signals) and ignore the discrepancy?

    The article mentioned hijacking scenarios, and I do expect that some criminal organization will attempt this within the next few years. I would imagine it's on the "Somali Pirates" shopping list right now. This sort of thing is right up there in "James Bond" diabolic scheme territory. You could electronically hijack an empty oil tanker. Drive it onto a beach. Alert the media. Then call up the "Leaders of the Free World" (got that on speed dial?) and demand $100 million dollars or you will repeat the trick with a fully-loaded oil tanker aimed right at a colony of very cute baby birds!!! You could explain that you would also accept a fully-functional ship motion simulator in lieu of cash. :)

    In the longer term, there will be renewed calls for a dramatically improved eLoran. This would essentially be a ground-based GPS capable of fully duplicating the continuous, all-weather, highly accurate position-finding capability of GNSS systems. It might not work in the middle of nowhere given frequency constraints (and satellites signals would cover such places), but it could be a much stronger signal and therefore far more difficult to jam. The GPS signals are notoriously low energy. In addition, you can expect calls for access to military-class "spoof-proof" systems for high-value targets, and that should creep down to any potential targets soon after.

    As for celestial navigation, it won't help much unless you're taking continuous, high-accuracy sights. An automated system, such as has been discussed by various people on and off for years here on NavList, would probably be the only viable option. Of course you're still out of luck on cloudy days. The nice side of this is that the hardware to do this is radically simpler than it was thirty years ago. It should be possible to equip aircraft with a self-contained automated celestial navigation package for as little as a few thousand dollars (or a few hundred if the market is big enough). It could never replace the accuracy and continuity of GPS or a future eLoran, but it would detect any obvious discrepancies.


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