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[aprssig] PCSAT-3 opportunity?

Curt, WE7U archer at eskimo.com
Tue Jun 26 16:11:31 UTC 2007


On Tue, 26 Jun 2007, Daron J. Wilson wrote:

> Have a GPS in mind?  I believe most of them stop reporting at a particular
> altitude (100,000 feet or so), I understood it may be a software 'feature'.

I know that GPS'es are flown on spacecraft.  The original specs from
the DOD? required that a GPS cease to function above a certain speed
and/or above a certain altitude.  The way the specs were worded it
was fuzzy whether it was an _AND_ relationship or an _OR_
relationship between the altitude and the speed.  Some GPS
manufacturers took it one way, some the other.  That's why you can
find GPS'es that work above that altitude for low-speed applications
like high-altitude ballooning.

For a satellite you'd not be able to find a commercial GPS that
would work for you as both the altitude and the speed would be above
the limits.  It'd have to be a military GPS or a commercial one with
special firmware that was somehow ok'ed by our government for the
project.

--
Curt, WE7U.   APRS Client Comparisons: http://www.eskimo.com/~archer
"Lotto:    A tax on people who are bad at math." -- unknown
"Windows:  Microsoft's tax on computer illiterates." -- WE7U
"The world DOES revolve around me:  I picked the coordinate system!"




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