If a modern warhead should land within a 100 meters or 20 meters would
bake little difference for a man on ground zero.


On 19 April 2013 13:27, RussellMc <apptechnz@gmail.com> wrote:

> > This came up in a conversation related to solar tracking. Will the
> > military shut off
> > ALL of the GPS services, or just positioning, during a wartime footing?
> >
> > How about time/date services?
>
> First casualty is to change to "selective availability"
> Accuracy drops substantially.
> This was the mode the system ran in fr many years when first introduced.
> AFAIR this was done for 'Desert Storm'.
>
> I do not know if it is done, but you could shut it down regionally so
> that a portion of the globe was without service. How small and well
> defined you could do this would be "interesting".
> A very determined person could gain useful information from two
> satellites and possibly from one.
>
> Russia operates a GPS system (GLONASS*) that (memory says) uses polar
> elliptical orbit satellites as in that orbit shape they are in the
> high poleward part of their orbit for the  majority of the time.
> Usefulness diminishes as you go southward. If they transmit around the
> whole orbit you MAY get some use from low altitude satellites in the
> southern hemisphere.
>
>
>
>           Russia
>
> ___________________
>
> http://en.wikipedia.org/wiki/Satellite_navigation
>
> http://en.wikipedia.org/wiki/Global_Positioning_System
>
> Says:
>
>            Initially, the highest quality signal was reserved for
> military use, and the signal available for civilian use was
> intentionally degraded (Selective Availability). This changed with
> President Bill Clinton ordering Selective Availability to be turned
> off at midnight May 1, 2000, improving the precision of civilian GPS
> from 100 meters (330 ft) to 20 meters (66 ft). The executive order
> signed in 1996 to turn off Selective Availability in 2000 was proposed
> by the U.S. Secretary of Defense, William Perry, because of the
> widespread growth of differential GPS services to improve civilian
> accuracy and eliminate the U.S. military advantage. Moreover, the U.S.
> military was actively developing technologies to deny GPS service to
> potential adversaries on a regional basis.[18]
>
> __________________
>
> GLONASS
>
> http://en.wikipedia.org/wiki/GLONASS
>
>          iPhone 4S, iPad Mini and HTC provide GPS & GLONASS capability.
>
>          GPS and phone baseband chips from  ST-Ericsson, Broadcom and
> Qualcomm support GLONASS in combination with GPS.
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