[ntp:questions] NTP rejecting SHM for NMEA GPS and PPS
David Taylor
david-taylor at blueyonder.co.uk.invalid
Sat Aug 11 15:08:38 UTC 2018
On 10/08/2018 23:16, natal at datacloud.com wrote:
> I forgot to mention that I am using Ubuntu 16.04 and the GPS receiver is connected via USB
USB is not the best to get good results. You need to connect the PPS
signal directly to a port on the device - typically the CD (carrier
detect) line on a _true_ serial port is used. Likely the
serial-over-USB is rejected because of excessive jitter.
I don't know whether you may have your "prefer" in the wrong place
without looking in detail. You need the "prefer" against a server which
will provide the coarse seconds (i.e. a clock) otherwise the PPS edge
will not be recognised (as NTP needs both coarse time and the exact
second). You may, or may not, be correct.
--
Cheers,
David
Web: http://www.satsignal.eu
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