[time-nuts] GPS backup for the stationary time and frequencyuser

Matthew Kaufman matthew at matthew.at
Sat Oct 9 14:47:37 UTC 2010


  On 10/8/2010 1:48 PM, Magnus Danielson wrote:
>
> I would not be supprised if they had not considered such a threat.
>
> This is a common threat for all bent-pipe birds. They have been jammed 
> before and we can expect them to be jammed again. However, I do not 
> think the WAAS or any similar is highest up on the target list as for 
> most uses it is a support-function rather than main function system.
> Birds which has been jammed is typically TV signal relays.
Threat model is different here. The end-user terminals for TV sats have 
narrow antennas looking at just that satellite, so it affects just that 
satellite/transponder.

The end-user terminals for GPS are looking at the entire hemisphere of 
sky, so if you can send spoofed signals from the WAAS transponder (same 
RF frequency that all the rest of the GPS satellites are using to talk 
to single-frequency receivers) and get the receivers to lock to these 
signals instead of the legitimate ones, you can interfere with *all* GPS 
reception, not just the WAAS signal, for the entire coverage area of WAAS.

Matthew Kaufman



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