[gpsd-users] Strange 14s offset with GPS 18x LVC

[Miroslav Lichvar]

Hi,

I've noticed some strange messages in syslog on a system synchronized by
gpsd (3.1) and chrony via SOCK. It seems the time reported by gpsd was off for
few minutes by exactly 14 seconds. The GPS unit is Garmin 18x LVC (3.70) in
NMEA mode, the enabled messages are RMC, GGA, GSA, GSV, RME.

>From the chrony refclocks.log:

===============================================================================
   Date (UTC) Time         Refid  DP L P  Raw offset   Cooked offset      Disp.
===============================================================================
2011-10-16 01:52:32.999998 SOC1   12 N 0  1.539000e-06  1.527000e-06  4.974e-07
2011-10-16 01:52:33.999999 SOC1   13 N 0  9.980000e-07  9.860000e-07  4.974e-07
2011-10-16 01:52:34.999999 SOC1   14 N 0  7.370000e-07  7.260000e-07  4.964e-07
2011-10-16 01:52:35.999999 SOC1   15 N 0  1.204000e-06  1.194000e-06  4.964e-07
2011-10-16 01:52:27.800001 SOC1    - N -       -        1.961000e-07  1.513e-07
2011-10-16 01:52:37.000000 SOC1    0 N 0  7.700000e-08  2.600000e-08  4.923e-07
2011-10-16 01:52:38.000000 SOC1    1 N 0  2.300000e-08 -2.500000e-08  4.923e-07
2011-10-16 01:52:38.999999 SOC1    2 N 0  5.610000e-07  5.160000e-07  4.923e-07
2011-10-16 01:52:39.999999 SOC1    3 N 0  8.060000e-07  7.640000e-07  4.923e-07
2011-10-16 01:52:41.000000 SOC1    4 N 0  1.400000e+01  1.400000e+01  4.923e-07
2011-10-16 01:52:42.000000 SOC1    5 N 0  1.400000e+01  1.400000e+01  4.913e-07
2011-10-16 01:52:43.000000 SOC1    6 N 0  1.400000e+01  1.400000e+01  4.903e-07
2011-10-16 01:52:44.000000 SOC1    7 N 0  1.400000e+01  1.400000e+01  4.903e-07
2011-10-16 01:52:45.000000 SOC1    8 N 0  1.400000e+01  1.400000e+01  4.893e-07
2011-10-16 01:52:46.000000 SOC1    9 N 0  1.400000e+01  1.400000e+01  4.883e-07

Any explanation what could be wrong or has anyone else seen this?

Thanks,

-- 
Miroslav Lichvar