[time-nuts] Using digital broadcast TV for timing?

[Magnus Danielson]

On 02/10/2012 06:56 PM, Bob Camp wrote:
> Hi
>
> I suspect that if you went into the GPS jamming business that the mob of
> lawyers would be even more scary than the stuff being dropped on your
> antennas...

Not even the US military could be that evil!!!

If you attempts that "total" jamming approach then you are probably a 
state. There are a few states which actually do such jammings to telecom 
sats. I think they would not care what the lawyers says. I also think 
the US air force would care about their strategic assets being under 
continuous attack.

Cheers,
Magnus

> Bob
>
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Magnus Danielson
> Sent: Thursday, February 09, 2012 4:17 PM
> To: time-nuts at febo.com
> Subject: Re: [time-nuts] Using digital broadcast TV for timing?
>
> On 02/09/2012 07:21 PM, Chris Albertson wrote:
>> On Wed, Feb 8, 2012 at 11:02 PM, Hal Murray<hmurray at megapathdsl.net>
> wrote:
>>>
>>>> Other than LightSquared, an event that made GPS go away would most
> likely
>>>> eliminate most interest in ultra accuracy time keeping.
>>>
>>
>> By "went away", I meant locally,  as be being jammed or spoofed.
>> Possibly a car drives into a tunnel and then from the car's point of
>> view GPS "goes away".
>>
>>   From a military point of view all it takes to knock out GPS is to
>> suicide truck-bomb both ground control stations or simply jam the GPS
>> uplinks so the stations are unable to send commands.   But The
>> question was more theoretical then practical.
>
> Let's assume that the physical safety of the ground control center is
> there, and just have a look at the jamming of up-links. Jamming the
> up-links would be a bit of a difficult task, since there is not one but
> several up-links, also you would need to high-energy jam all the birds
> as you would not know when they would get their commands. Add their
> capability of cross-link communication and ability to uphold a decent
> situation in autonav for ground station outage of up to 180 days. Oh,
> both uplink and cross-link is encrypted and fairly jam-resistant.
> Cross-link has nulls towards earth and only a half-decent gain in
> certain angles.
>
> All that comes out of public sources. It would take a bit of resources
> to do a global GPS outage, and to maintain it you would expose yourself
> over a long time such that you would be found and well, let's assume
> that your antennas will not take kindly to the things being dropped at it.
>
> Regional outages is much easier.
>
> Cheers,
> Magnus
>
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