[time-nuts] Ships fooled in GPS spoofing attack suggest Russian cyberweapon

jimlux jimlux at earthlink.net
Mon Aug 14 15:07:48 EDT 2017

On 8/14/17 10:24 AM, Magnus Danielson wrote:
> Hi Jim,
> On 08/14/2017 06:03 PM, jimlux wrote:
>> And GPS users who care about spoofing tend to use antenna systems that
>> will reject signals coming from the "wrong" direction.  It's pretty
>> easy to set up 3 antenna separated by 30 cm or so and tell what
>> direction the signal from each S/V is coming from.
>> I would expect that as spoofing/jamming becomes more of a problem
>> (e.g. all those Amazon delivery drones operating in a RF dense
>> environment) this will become sort of standard practice.
>> So now your spoofing becomes much more complex, because the sources
>> have to appear to come from the right place in the sky.  (fleets of
>> UAVs?)
> You gain maybe 10 to 20 dB, but not much more.
> A real protection scheme needs much more tolerance to handle severe
> problems.

I think it is more about are looking for "spoof detection" or "spoof 
immunity"..  Spoof detection is a easier bar.

> There is an overbeliefe in such approaches, rather than trying to look
> at the system analysis, since when you loose the GPS signal, what do you
> do. I get blank stares all too often when I ask that trick question.

Most successful schemes rely on "side information" of one sort or 
another - whether from an IMU or from other sources.  Acquisition is 
always more vulnerable than track.

I don't do much, if any, of this stuff these days - that was more my 
thing in the mid-80s when I would killed to have the cheap processing 
power and fast data converters available today.

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