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

[Magnus Danielson]

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.

Indeed.

> 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...

Cheers,
Magnus