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George and list:

There's mention of this failure (due to the failure of the atomic clock
on one of the satellites) in
www.ion.org/sections/southcalifornia/ lavrakas_civil_gps_monitoring.ppt

I was rather surprised to learn that there is NOT continuous monitoring
of the GPS system for integrity of its positioning information, given
that there's a whole new generation of air traffic control that's going
to be based on GPS...

Lu Abel

George Huxtable wrote:
> I know that references to GPS are discouraged, if not forbidden, on this
> list. But I wonder if a note about GPS shortcomings would be more
> acceptable?
>
> I've just received a leaflet from the British Lighthouse authorities,
> pushing for use of the new Loran-C transmitter at Rugby, England.
>
> In which is the statement-
>
> "GNSS systems themselves also suffer occasionally from undetected failures;
> for example, a satellite clock error on 1 January 2004 gave rise to errors
> in measured positions of up to 45 kilometres in Western Europe for a period
> of some 3 hours, resulting in onboard navigational failures."
>
> I hadn't heard about that event, which sounds rather serious. Is it common
> knowledge? Can anyone offer further details?
>
> It wouldn't have affected me. I would have been by the fireside on that day.
>
> George.
>
> ================================================================
> contact George Huxtable by email at george@huxtable.u-net.com, by phone at
> 01865 820222 (from outside UK, +44 1865 820222), or by mail at 1 Sandy
> Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
> ================================================================
>
>

   

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