> Paul Walbridge wrote:
>
> Hi all, this article appeared in saturdays Courier Mail in Queensland and
> could of some concern to fellow Atlassers.
> NAVIGATION DEVICE RISK
>
>
> " Hikers, fishermen and sailors who rely on electronic navigation could
> find themselves lost on August 21 because of a bug in the global position
> satellite system.
> The American-built satellite network calculates the date by counting the
> weeks since it was set up in January 1980.And when the counter hits 1024
> weeks, it is programmed to restart at zero.
> Warren Entsch, parliamentary secretary to the Minister for Science and
> Industry, yesterday warned that the zero date could cause some GPS
> recievers to look for satellites in the position they were nearly 20
> years ago."
>
> My concern is, is there any truth in this or is it just another one of
> those political beat-ups emanating from one of those paranoid American
> Congressmen or Senators.
The GPS End of Week (EOW) rollover "problem" occurs every 20 years or so
(1024 weeks), though this is the first time it has happened since GPS
came into existance. The GPS satellites will *not* be affected by this
or the Year 2000 (Y2K) problem.
It is possible that some receivers (particularly older models) may have
a problem and require a firmware upgrade or some other action to correct
it; in many cases, a "cold start" initialisation is all that is required.
Check with your manufacturer if you have any concerns.
Some links to GPS manufacturers' web pages on the subject:
Garmin: http://www.garmin.com/faqs/1.html
Magellan: http://www.magellangps.com/customer/y2k.htm
Eagle: http://www.eaglegps.com/egps/svc/y2k.htm
Lowrance: http://www.lowrance.com/service/y2k.htm
Trimble: http://www.trimble.com/y2kwnro/chart.htm
Unfortunately, there is so much hype about the Y2K problem at the moment
that the media go into a frenzy about any possible date problem without
doing their research. For example, "9/9/99" is a frequently quoted date.
The value "9999" was often used in COBOL programs to indicate end-of-data;
the date 9/9/99 is coming up, so the computer systems are going to break!
Wrong - if you consider other dates that have already passed, for example
1/11/98 and 11/1/98, you can see that storing them without zeroes would
be extremely foolish. 9/9/99 is no exception, and would be stored as
"090999" or "990909" - not "9999". I'm surprised we haven't heard more
about the "odometer rollover problem" and other modern day numerology.
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Paul Taylor Veni, vidi, tici -
I came, I saw, I ticked.
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