[ntp:questions] Multiple PPS Lines

Matt Corallo ntp-lists at mattcorallo.com
Tue Sep 15 17:00:17 UTC 2020

Also, while I'm on the subject, what about multiple "prefer" peers? I've seen several folks indicate that they have "two 
GPS receivers" or the like, but there doesn't seem to be a good way to configure ntpd for that use-case.


On 9/15/20 12:26 PM, Matt Corallo wrote:
> Is there any interest in a patch to select across multiple PPS lines (maybe median of the available lines, or maybe 
> using clock_combine) instead of just blindly taking the first one? This would also allow us to take the second available 
> PPS line if the first one fails the "within 400ms" requirement.
> Also, would it make sense to add a flag for "PPS, but with known time" which could be used in eg GPSD_JSON(N+128) 
> refclocks, indicating that while this is a PPS input, it is *also* a clock that knows what time it is.
> Finally, how maintained is GPSD_JSON? There's some pretty big show-stoppers I filed at 
> https://bugs.ntp.org/buglist.cgi?product=ntp&component=refclock%20-%20gpsdjson&resolution=---&list_id=15257 (that now 
> have patches attached).
> Matt

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