[TriEmbed] that recent 14usec GPS error wrt UTC

jonjwolfe at anibit.com jonjwolfe at anibit.com
Thu Jan 28 10:51:10 CST 2016


I should have added smiley to indicate I was being facetious.

;)

On 2016-01-28 09:44, Jon Wolfe wrote:
> Being in the middle of re-reading "a brief history of time" (I
> received an illustrated edition for xmas, it's awesome), I can't help
> but wonder, gravity waves?
> <br><br>-------- Original message --------<br>From: Pete Soper via
> TriEmbed <triembed at triembed.org> <br>Date: 1/28/2016  11:39 AM
> (GMT-05:00) <br>To: Triangle Embedded Interest Group
> <TriEmbed at TriEmbed.org> <br>Subject: [TriEmbed] that recent
> 14usec GPS error wrt UTC <br><br>
> 
> Recently the time info from the GPS satellite system experienced a
> hiccup and its reckoning of UTC time was momentarily off by about 14
> microseconds. This got a lot of people's attention, because they're of
> course used to this stuff being very precise and there's a lot of
> heavy duty dependence. Paul Boven figured this out and his explanation
> was put on today's time-nuts list digest:
> 
> "We were able to track this down today at Meinberg.
> 
> The problem was that some satellites were sending invalid UTC
> correction
> parameters. The UTC correction parameter set not only contains current
> leap second information but also coefficients (A0, A1, WNt, tot) for a
> polynomial used to compensate the fractional difference between GPS
> time
> and UTC(USNO).
> 
> Today the faulty satellites sent about 13.7 microseconds for A0, and
> WNt
> as well as tot were both 0. So when the GPS receiver updated its UTC
> correction parameters from a faulty satellite the UTC correction
> jumped
> from close to 0 to about 13.7 microseconds, which let the UTC time
> step,
> and when the GPS receiver received the UTC parameter set from a
> healthy
> satellite the UTC time stepped back."
> 
> -Pete
> 
> _______________________________________________
> Triangle, NC Embedded Computing mailing list
> TriEmbed at triembed.org
> http://mail.triembed.org/mailman/listinfo/triembed_triembed.org
> TriEmbed web site: http://TriEmbed.org
> 
> Recently the time info from the GPS satellite system experienced a
> hiccup and its reckoning of UTC time was momentarily off by about 14
> microseconds. This got a lot of people's attention, because they're of
> course used to this stuff being very precise and there's a lot of
> heavy duty dependence. Paul Boven figured this out and his explanation
> was put on today's time-nuts list digest:
> 
> "We were able to track this down today at Meinberg.
> 
> The problem was that some satellites were sending invalid UTC 
> correction
> parameters. The UTC correction parameter set not only contains current
> leap second information but also coefficients (A0, A1, WNt, tot) for a
> polynomial used to compensate the fractional difference between GPS 
> time
> and UTC(USNO).
> 
> Today the faulty satellites sent about 13.7 microseconds for A0, and 
> WNt
> as well as tot were both 0. So when the GPS receiver updated its UTC
> correction parameters from a faulty satellite the UTC correction jumped
> from close to 0 to about 13.7 microseconds, which let the UTC time 
> step,
> and when the GPS receiver received the UTC parameter set from a healthy
> satellite the UTC time stepped back."
> 
> -Pete
> 
> 
> _______________________________________________
> Triangle, NC Embedded Computing mailing list
> TriEmbed at triembed.org
> http://mail.triembed.org/mailman/listinfo/triembed_triembed.org
> TriEmbed web site: http://TriEmbed.org





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