[time-nuts] GPS Spoofing

[Brian Alsop]

If you know your LORAN has a 1/4 mile accuracy then you stay 1/2 mile 
away from bad things.

The trouble with GPS is that it is so good, people don't use common 
sense and give obstacles a wide berth.

Brian

On 7/27/2013 04:21, Jim Lux wrote:
> On 7/26/13 8:45 PM, J. Forster wrote:
>> I gather from the article, the GPS position was spoofed and the
>> autopilot,
>> in bringing it back to where it was supposed to be, actually took it off
>> course.
>>
>> There are places where a few hundred feet makes a big difference, viz.
>> the
>> Costa Concordia.
>>
>> IMO, this is a very convincing reason for something like LORAN.
>
> I think it's a convincing argument for a captain who pays attention to
> the other navigation instruments and doesn't blindly follow the GPS.
>
> It's also a convincing argument that shipboard
> automation/autopilot/autocontrol vendors need to make more sophisticated
> software (which I suspect they do, particularly on 200+ foot ships.. I
> would imagine that there are some aspects of this demo that are
> contrived.)  The ship making and driving business is pretty unregulated.
> It's all about what the owner of the ship is willing to pay (or what he
> needs to get liability insurance, if he wants).  There's nothing even
> remotely like DO-178 for shipboard stuff.
>
> The folks doing stabilized oil rigs probably have sophisticated systems,
> but they're also using IMUs and other stuff. Ditto for high value things
> (oil tankers, warships).  Molasses tankers? They're probably lucky to
> have a functioning compass and some old charts.
>
>
> I'm not sure, though, that looking at the big picture, whether your tax
> dollars are better spent on LORAN, or on some other precision navigation
> method or on making jam resistant GPS receivers (which do, in fact
> exist, and make use of things like direction of arrival of the signal..)
>
> Note that a GPS system with 3 antennas (as is common in systems that use
> GPS to derive attitude/orientation) would be extremely difficult to
> spoof, and would be VERY inexpensive to implement.  Either the carrier
> phases and code phases are consistent for all the received signals or
> they're not.  A jamming signal coming from the wrong direction will not
> have the right direction of arrival relative to the platform
> orientation.  One wrong signal might be tolerable (multipath, etc.) but
> with a multi satellite fix, I suspect it would be hard to do it.
>
> Sure, one could throw up N pseudolites on a bunch of UAVs, etc., but
> that's getting to be a bit noticeable.
>
>
> For what it's worth, I don't know that LORAN has the performance to
> avoid a Costa Concordia type foul up (assuming they were crazy enough to
> do the near pass in the fog, so visual navigation didn't work)
>
> I seem to recall that LORAN had 1/4 nmi kinds of accuracy.  it would get
> you to the channel or mouth of the harbor, but not get you into your
> berth. You might be familiar with the local propagation anomalies and
> get better accuracy with experience in your local waters.
>
>
>
>
>
>
>>
>> -John
>>
>> =================
>>
>>
>>
>>> I boat?  The backup is a competent captain.  He'd see the compass
>>> heading
>>> move and quickly disengage the autopilot.   I had a boat for years  I'd
>>> notice a 5 degree change.  Mine was a sailboat so I'd be more
>>> sensitive to
>>> heading changes than a power boater but still the human is the backup.
>>>
>>> Most autopilots don't directly follow GPS, they use GPS to determine a
>>> heading, follow it then use GPS to detect drift and re-compute the
>>> heading.
>>>   the heading would be held by a compass sensor in a low-cost setup
>>> or in a
>>> larger setup a lazer ring gyro backed up by a compass.     So a spoofed
>>> GPS
>>> would cause the autopilot to "think" there was a bigger crooswnd or
>>> current
>>> and make a bigger heading change.
>>>
>>> I bet you could hijack a drone not a manned vehicle the pilot is trained
>>> to
>>> monitor the automation and he'd very quickly turn it off thinking it was
>>> broken.
>>>
>>>
>>>
>>>
>>>
>>>
>>> On Fri, Jul 26, 2013 at 8:41 AM, J. Forster <jfor at quikus.com> wrote:
>>>
>>>> Prof. Humphry from Texas just reported being able to spoof GPS in the
>>>> Med
>>>> and take over the nav system of a luxury yacht. He's done this before
>>>> with
>>>> a drone in the US.
>>>>
>>>> LORAN as a backup, at least?
>>>>
>>>> -John
>>>>
>>>> ==============
>>>>
>>>>
>>>>
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>>>
>>>
>>>
>>> --
>>>
>>> Chris Albertson
>>> Redondo Beach, California
>>>
>>
>>
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