[time-nuts] "The GPS navigation is the weakest point,"

Reeves Paul Paul.Reeves at uk.thalesgroup.com
Fri Dec 16 03:32:43 EST 2011

 I seem to remember a recent 'jamming' trial off the east coast of England
that didn't kill the GPS but did shift the position of the ships involved -
certainly enough to get them aground or to hit something if they weren't
paying attention. I think one showed up inland - which should have been
suspicious! Sorry, cannot remember the reference but was mentioned in GPS
World, I think.

Paul Reeves         G8GJA

-----Original Message-----
From: gary [mailto:lists at lazygranch.com] 
Sent: 15 December 2011 23:45
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] "The GPS navigation is the weakest point,"

I've talked to the GPS jammers at Nellis and have seen their gear. They
don't spoof but just jam. The gear is totally COTS. Some Marconi signal
generator that can generate white noise at the two GPS frequencies. They
have omni or directional antennas. They have an old Russian jammer on hand,
but the Marconi works a lot better.

I've been jammed by them. It is interesting in that the GPS just suddenly
dies. That is, it seems to track given some noise, but you hit a point where
it suddenly gives up. It is the only time I've seen no satellites shown on
the display.

It wouldn't surprise me if a Growler could spoof a GPS, but I have no hard
evidence that it can.

I'm in agreement with they just jammed everything and the thing ran out of
fuel. I have a FOIA somewhere on a Predator crash. With LOS, it just orbits.
In the case of this Predator, it orbited into a mountain near Creech AFB.

On 12/15/2011 3:18 PM, Chris Albertson wrote:
> I bet this drone contains no technology that is not exportable.  Of 
> course they had to think about a crash.
> I also bet it had an inertial nav system as backup to the GPS.   But
> and this is the key to all backups.  You have to know the primary is
> failed.   When you jam GPS the smart way is not to over power it with
> white noise but to first transmit an IDENTICAL signal.  Then very 
> slowly move your stronger signal away from "truth" until it is sending
> a false signal.   This way the receiver does not know it is being
> jammed.  No I did not just think of this, it's what "everyone" does.
>   But why then if the INS and GPS disagree was there not an alarm?   It
> was likely a low-cost INS that needed periodic updates from a GPS
> I would not rule out that they simply made the drone fly into a big 
> fishing net and dropped it with a parachute in a kind of controlled
> mid air collision.   Heck the US used to capture film cam falling from
> space with big nets
> Chris Albertson
> Redondo Beach, California
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