[email protected] writes: >Hello,
>I'm using a Garmin 18 LVC connected using LinuxPPS with mostly good results. >I am curious about one thing though. The offset reported by the GPS18 >differ from the public NIST servers by around 1.7-1.9MS. as shown in the >offset numbers of ntpq below. > remote refid st t when poll reach delay offset jitter >============================================================================== >*GPS_NMEA(0) .GPS. 0 l 4 16 377 0.000 -0.448 0.189 >+bigben.cac.wash .USNO. 1 u 34 1024 377 11.134 0.283 2.645 >All of the server's internet peers are ahead by around that same value so >I'm guessing that when the GPS18 loses sync, ntpd would have to bring the >clock up by 2MS and reverse when signal is reacquired. Sorry, where is that 1.7-1.9ms? I see a difference of .7ms, which, given the 11 ms delay is pretty good. >Is there any way to know whether it's our internet link (ADSL) causing the >internet servers to appear off or does the GPS18 need a time1 fudge to bring >it in line with the others? That is, is there a 2MS lag in processing the >interrupt for PPS? If there is a 2ms delay is processing the interrupt, throw away your system and buy a new one. It is severely damaged. _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
