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

[Magnus Danielson]

On 12/15/2011 11:06 PM, Jim Palfreyman wrote:
> Fascinating.
>
> I can picture setting up a bunch of transmitters in the hills to send out
> strong GPS-like signals to mimic the real thing. I suppose you could
> control those signals to fool the device it is somewhere else. That bit is
> very clever - you'd have to adjust the signals taking into account current
> positions of all current satellites. Smart bit of work there.
>
> But it would also need incredible timing. Even a few ns out and it wouldn't
> work. So how do you set up fantastic timing at different locations of
> transmitters throughout a country. Well you've blocked the GPS - so that's
> no good.
>
> It would require local atomic clocks (good ones) at each location.
>
> Do they have access to such things? Maybe I'm being naive.

To transmit a GPS cluster signal you need a GPS simulator to generate 
the cluster so even a single transmitter can do this, the relative 
timing and not the different positions of the transmitters is what the 
receiver sees.

When over-powering the real birds you just needs to be close enough in 
timing, and it is the location of the target which is of interest.

If this scenario is true... then they have not done their home-work. I 
would ask a number of critical questions already from my civilian 
background.

Cheers,
Magnus