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

Magnus Danielson magnus at rubidium.dyndns.org
Sat Oct 9 15:00:31 UTC 2010

On 10/09/2010 04:47 PM, Matthew Kaufman wrote:
> 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.

Hmm. Yes. Creative! Once demonstrated essentially all WAAS/EGNOS/SBAS 
sats need to develope some protective measure.

To pull it off, a standard GPS simulator and some minor frequency 
conversion is needed. Should not stop the handy man.

It would be an interesting legal aspect to attempt to charge the guilty...


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