On Thursday, November 28, 2013 6:15 AM Miroslav Lichvar wrote: >On Wed, Nov 27, 2013 at 04:06:58PM -0500, Battocchi, Scott L. wrote: >> I ran the GPS while connected to a handful of ntp servers and saw that my >> gps offset (originally 0.180) was too low, so I bumped it up to 0.530 for >> the next two tests. I've attached plots of the offset as recorded in the >> statistics.log file, if there are other metrics that would be useful I'm >> happy to graph them and send them out. >> ntp.png is with 5 pool servers and the GPS set to noselect (PPS is not >> locked to anything, but is selectable) gps.png is after the ntp test but >> back to just using the GPS and PPS, it looks like sometimes GPS gets >> selected as the source forcing the PPS signal to look like it is drifting >> relative to the system.
>That looks similar to what I see with with a Garmin 18x LVC. This is a capture >30 hours long I did some time ago (the NMEA source's offset value was set to >0.5): >http://mlichvar.fedorapeople.org/tmp/18x_nmea.png >Since gpsd has added support for kernel PPS, I think it's better to use the >SHM 1 or SOCK source instead of PPS. Let it handle the HW details and pair the >PPS and NMEA samples. I could not see how to get GPSD to associate a kernel PPS source (our /dev/pps1 is driven by the PPS-GPIO kernel module and does not come in through the serial port's DCD line) with a NMEA source. Without a PPS signal coming into GPSD I didn't seem to get any data into chrony through the SOCK interface even though GPSD did see and successfully connect to it according to the GPSD debug output. Thanks, Scott -- To unsubscribe email chrony-users-requ...@chrony.tuxfamily.org with "unsubscribe" in the subject. For help email chrony-users-requ...@chrony.tuxfamily.org with "help" in the subject. Trouble? Email listmas...@chrony.tuxfamily.org.
