GPS

[Shawn Mamros]

>Interesting news that says the White House is keeping open the option of 
>being able to shut down GPS over the U.S. in the event of a major crisis 
>so as to prevent the GPS to be used against us.  I was unaware that the 
>GPS system is so neatly linked that it could be brought off-line.  Would 
>the entire set of birds be shut down?  If so, what else shares those 
>birds and would be similarly affected, broadcast, financial links, 
>weather, other critical services?

IIRC, GPS was originally developed by and for the U.S. military, and
they still use it.  In fact, they have access to a greater degree of
pinpoint accuracy than what they allow to be available for civilian
use.  So they likely wouldn't shut down GPS altogether, but instead
lock out civilian access, while they still would use it themselves.

And I'm pretty certain GPS uses its own set of satellites, rather
than shared space on civilian communications satellites, for the
very same reason.  But even if they didn't, I would think satellites
these days would provide control over individual transponders, such
that you could turn one or more off while keeping others on.

-Shawn Mamros
E-mail to: mamros -at- mit dot edu