Re: [chrony-users] Synchronize system clock to GPS time

On Fri, Mar 04, 2022 at 04:22:52AM +, Ryan Govostes (he/him) wrote: > Then I tried removing the offset 0. from the GPS ref clock — this was > recommended in some tutorial somewhere and obviously is not the correct value > to use, and when I removed it, the system clock updated right away.

Re: [chrony-users] Synchronize system clock to GPS time

The gps receivers deliver full UTC time (well GPS time but they are almost equivalent) Each appropriate sentence from GPS includes the time to the second. (it is randomly delayed because GPS sentences are delivered with low priority, and the characters coming over a serial port take about a a bit

Re: [chrony-users] Synchronize system clock to GPS time

On Fri, 4 Mar 2022, Adrian Murphy wrote: [CAUTION: Non-UBC Email] On 4 Mar 2022, at 2:52 pm, Ryan Govostes (he/him) wrote: Hi Adrian, Thanks for the pointers. asdf.xyz was indeed just a throwaway host instead of my real NTP server. I removed that server line but it did not seem to have

Re: [chrony-users] Synchronize system clock to GPS time

Does the PPS ref clock actually provide a time of day or anything, though? I thought it merely told us when to tick the second hand forward. Or is GPSD combining the two and sending a full timestamp over the socket? In which case, do I need the GPS refclock at all? Or if I need both, how does o

Re: [chrony-users] Synchronize system clock to GPS time

> On 4 Mar 2022, at 2:52 pm, Ryan Govostes (he/him) wrote: > > Hi Adrian, > > Thanks for the pointers. > > asdf.xyz was indeed just a throwaway host instead of my real NTP server. I > removed that server line but it did not seem to have an effect. > > Then I tried removing the offset 0.999

Re: [chrony-users] Synchronize system clock to GPS time

Teh two sources GPS and PPS have vastly different uncertainties. so the system would tend to choose the PPS and ignore the GPS. The GPS will also tend to be much more than a few standard deviations away from the PPS. So it will not combine the output of the GPS with the PPS. It is like if you had

Re: [chrony-users] Synchronize system clock to GPS time

Hi Adrian, Thanks for the pointers. asdf.xyz was indeed just a throwaway host instead of my real NTP server. I removed that server line but it did not seem to have an effect. Then I tried removing the offset 0. from the GPS ref clock — this was recommended in some tutorial

Re: [chrony-users] Synchronize system clock to GPS time

Hi Ryan, Can I ask: You have ‘prefer’ option added to the 'server asdf.xyz’ line. Could that be stopping chronyd from trusting the GPS? Also, asdf.xyz does resolve to an NTP server for me, but maybe you are hiding the real hostname. On Ubuntu Raspberry Pi4 I use: refclock SOCK /run/chr

[chrony-users] Synchronize system clock to GPS time

I have a GPS receiver with PPS connected to an embedded Linux system. GPSD feeds Chrony time updates from the GPS receiver over the Chrony socket. The system clock is behind by a few months, and Chrony does not want to update the clock to the time reported by GPSD. I have read the FAQ and a few