[aprssig] Terrestrial Threat to GPS Has Now Hit The Manstream Media

[Bernard Van Haecke]

This is a non issue unless the jammer is sitting on a sat or airplane.

If terrestrial and uses high power, he will be DF'ed in no time.

Otherwise, this story is a joke.

Bernard

Sent from my EVO android phone
On Apr 10, 2011 10:44 AM, "Alex Carver" <kf4lvz at yahoo.com> wrote:
>
>> From: "Rahn Abbott"
>>
>> Ummmm, you do know that that US Military GPS units and your
>> Garmin Etrex are
>> not listening to the same radio signals right? You do know
>> military and US
>> government GPS runs on a completely different system?
>
>
> No, the military listens to both L1 at 1.57542 GHz (the "civilian" GPS
signal) and L2 at 1.22760 GHz, the military-only GPS signal. They use both
signals in order to determine delays caused by the ionosphere which improves
the accuracy of the military GPS receivers. If interference is caused to the
L1 signal it will affect both civilian and military users.
>
> A military GPS receiver and a civilian GPS receiver both listen to L1 but
they each use a different chipping code (civilian uses unencrypted C/A and
military uses both unencrypted C/A and encrypted P). Only the military GPS
receiver listens to L2 at the same time.
>
> Later on there will be new codes (L1C and M) as new satellites are put in
orbit but they will still have both civilian and military codes sitting on
L1. In addition, civilians will soon have access to L2 in the form of a
civilian code on L2 (L2C) which will allow for some basic ionospheric
corrections to improve accuracy and reduce drift. It won't be as accurate as
the military receivers but better than the current L1-only receivers.
>
> _______________________________________________
> aprssig mailing list
> aprssig at tapr.org
> https://www.tapr.org/cgi-bin/mailman/listinfo/aprssig
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.tapr.org/pipermail/aprssig_lists.tapr.org/attachments/20110410/7033c1fe/attachment.html>