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Richard,

Could you comment on the resurgence of Loran?

Thanks,

Fred

On Jun 8, 2005, at 3:52 PM, Richard Langley wrote:

> GPS IS monitored for integrity but by WAAS! The problem WAS detected
> by WAAS
> and the offending satellite was marked as "do not use." Consequently
> WAAS
> users were protected from this anomaly.
> -- Richard Langley
>    Professor of Geodesy and Precision Navigation
>    Fellow of The Institute of Navigation
>
> On Wed, 8 Jun 2005, Lu Abel wrote:
>
>> 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.
>>> ================================================================
>>>
>>>
>>
>
>
> =======================================================================
> ========
>  Richard B. Langley                            E-mail: lang@unb.ca
>  Geodetic Research Laboratory                  Web:
> http://www.unb.ca/GGE/
>  Dept. of Geodesy and Geomatics Engineering    Phone:    +1 506
> 453-5142
>  University of New Brunswick                   Fax:      +1 506
> 453-4943
>  Fredericton, N.B., Canada  E3B 5A3
>      Fredericton?  Where's that?  See:
> http://www.city.fredericton.nb.ca/
> =======================================================================
> ========
>

   

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