Re: [chrony-users] Not getting time from gpsd

[Chris Greenman <chris.m.greenman@xxxxxxxxx>]

No. We're just fine tuning the refclock line in chrony.conf.  I don't really experience huge jumps.  It might fall behind during a reboot because the pi doesn't have an RTC but rather it saves time on shutdown and restores on boot.

Really my only goal is to have somewhat accurate (less than a second) time whether I have internet or not.   We've already achieved this, now it's just a matter of making sure GPS doesn't clobber ntp and vice versa.

On Aug 14, 2016 7:24 PM, "Bill Unruh" <unruh@xxxxxxxxxxxxxx> wrote:

Is this supposed to be at a time when your system suddenly looses track of the
time and jumps by hours or days? I see nothing in the gps signal that
indicates anything like that.

If it is supposed to be at the begining of this sample, please give a sample
which spans across, not begins at, one of those weirdnesses.

Note also that probably a copy of the measurements and the refclock logs ove
onw of those times might be more illuminating. Statistics is rather processed
already.






William G. Unruh __| Canadian Institute for|____ Tel: +1(604)822-3273
Physics&Astronomy _|___ Advanced Research _|____ Fax: +1(604)822-5324
UBC, Vancouver,BC _|_ Program in Cosmology |____ unruh@xxxxxxxxxxxxxx
Canada V6T 1Z1 ____|____ and Gravity ______|_ www.theory.physics.ubc.ca/

On Sun, 14 Aug 2016, Chris Greenman wrote:

Ok  I grabbed a sample of the clock statistics.  


On Fri, Aug 12, 2016 at 2:53 PM, Bill Unruh <unruh@xxxxxxxxxxxxxx> wrote:
      On Fri, 12 Aug 2016, Chris Greenman wrote:

            it's a usb puck.  so no.  Actually I haven't actually looked but
            typical USB is +5v data+ data- and gnd.  As
            far as I know the only place the pps signal is available is inside the
            puck between the GPS module and the usb
            interface.  


      Well, usb serial immitatiors can also immitate the control lines from a serial
      line. Thus one of the usb packets can be a simlation of the PPS signalalong
      the appropriate serial line.  But those are likely to have far worse behaviour
      than the actual lines.
      It might however be better than the data phrases usually coming along the
      serial line.



             like I said I COULD crack it open and run a new cable that included
            the pps line.

            On Fri, Aug 12, 2016 at 2:24 PM, Bill Unruh <unruh@xxxxxxxxxxxxxx>
            wrote:


                  William G. Unruh __| Canadian Institute for|____ Tel:
            +1(604)822-3273
                  Physics&Astronomy _|___ Advanced Research _|____ Fax:
            +1(604)822-5324
                  UBC, Vancouver,BC _|_ Program in Cosmology |____
            unruh@xxxxxxxxxxxxxx
                  Canada V6T 1Z1 ____|____ and Gravity ______|_
            www.theory.physics.ubc.ca/

                  On Fri, 12 Aug 2016, Chris Greenman wrote:

                        I CAN hook it up for PPS but it will require cracking open
            the puck and it's not that
                        crucial for my use
                        anyway.  


                  Isn't there an output line from the puck which carries the PPS
            signal?