On Mon, Jan 23, 2017 at 1:03 PM, Harlan Stenn <st...@ntp.org> wrote: > Lloyd Dizon writes: > > Hi. > > I've installed a GPS module on a Raspberry Pi and I'm getting 1000ms > > offsets between the GPS readings and network NTPs. > > > > lloyd@jadzia:~ $ ntpq -p > > remote refid st t when poll reach delay offset > > jitter > > ============================================================ > ================= > > = > > LOCAL(0) .LOCL. 10 l 447 64 100 0.000 0.000 > > 0.001 > > Why are you using the LOCAL refclock? >
I shouldn't. I removed it now. > xGPS_NMEA(0) .GPS. 0 l - 16 377 0.000 6.229 > > 142.320 > > Is your NMEA source identifying the wrong second? > > > *ntp0.as34288.ne 85.158.25.74 2 u 24 64 3 9.810 1004.83 > > 1.687 > > +246.11.25.212.f 162.23.41.10 2 u 19 64 3 10.636 1004.22 > > 1.376 > > +ch-ntp01.10g.ch 81.94.123.17 3 u 21 64 3 10.493 1001.79 > > 3.299 > > -khyber.madduck. 192.33.96.102 2 u 20 64 3 8.703 1001.72 > > 4.474 > > Your NMEA source is sending ntpd samples every 16 seconds. It's filling > the sample buffer, and the the other sources (are you using iburst on > these? You should be...) are taking a while to provide enough samples > to detect that your NMEA source is "off" by a second. > I changed the min and maxpoll to 6 to be consistent with the network servers. I'm still getting a 1000ms offset though. > Anybody has a clue what is going on? > > I think your NMEA signal is identifying the wrong second. > So my NMEA device is broken then. Is there a way to compensate manually if the device is systematically adding (or subtracting) 1000ms. Is is correct to compensate manually. I looked at the time1 argument to fudge but I only had 300ms removed from the offset. Before using "time1 1": Every 1.0s: ntpq -pn Mon Jan 23 15:27:46 2017 remote refid st t when poll reach delay offset jitter ============================================================================== x127.127.20.0 .GPS. 0 l 48 64 17 0.000 10.095 6.428 *178.209.53.202 166.171.80.13 3 u 31 64 37 11.298 1015.56 9.837 +81.94.123.16 85.158.25.74 2 u 30 64 37 9.788 1013.30 9.577 +212.51.144.44 .PPS. 1 u 28 64 37 9.864 1013.35 9.723 +82.197.188.130 195.186.1.100 3 u 32 64 37 9.832 1013.75 9.664 After using time1 1: Every 1.0s: ntpq -pn Mon Jan 23 15:28:27 2017 remote refid st t when poll reach delay offset jitter ============================================================================== 127.127.20.0 .GPS. 0 l 16 64 0 0.000 0.000 0.001 *192.33.96.102 .PPS. 1 u 4 64 1 13.617 721.727 0.112 +5.148.175.134 131.188.3.222 2 u 4 64 1 9.377 720.615 0.436 +81.94.123.17 85.158.25.74 2 u 3 64 1 9.659 720.234 0.552 -46.22.26.12 162.23.41.56 2 u 2 64 1 15.923 722.333 0.171 _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions