[ntp:questions] UTC Time from NMEA receiver one second behind DCF?

Harald Brinkmann hb7267 at gmx.de
Tue Aug 12 21:09:31 UTC 2008


Hal Murray wrote:

A long time ago I wrote:
>>Last Saturday (2008-08-02) I noticed for the first time that the time off
>>the GPS unit was one second behind the DCF time, which I monitor on a
>>separate radio clock. A reboot of the system did not help. On Sunday
>>(2008-08-03) everything was back to normal. I noticed the same effect
>>again on Friday evening (2008-08-08) and through yesterday (2008-08-09),
>>but everything seems fine today (2008-08-10).
> 
> [big snip]
> 
>>My question is, has anyone else observed this and how can I fix this?
> 
> I've seen similar quirks from GPS units using the SiRF chip set.
>   http://www.megapathdsl.net/~hmurray/ntp/leap-gps3.gif
> 
> It started about the time the leap second was announced.  (Otherwise,
> they work, but not very well.  They have a 100 ms jitter/drift.)
> 
> It looks like a weekly pattern.  It will be interesting to see what
> happens during the next week.

Yes, that fits my observations well, including the weekly pattern...so far.
I suppose you don't know of any workaround for ntp purposes?

Cheers

Harald




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