[ntp:questions] Odd offset for PPS DCD w/ Garmin GPS 18x LVC
David J Taylor
david-taylor at blueyonder.co.uk.invalid
Tue Mar 22 17:21:31 UTC 2011
"lellis" <larry.ellis at gmail.com> wrote in message
news:efc6e755-c213-4a10-90f9-420384001da3 at s18g2000prg.googlegroups.com...
> On Win XP, I am seeing an odd positive offset of about 128ms on the
> Atom driver, relative to other sources:
> remote refid st t when poll reach delay
> offset jitter
> *GPS_NMEA(1) .GPS. 0 l 6 16 377 0.000
> 0.373 0.919
> xPPS(1) .PPS. 0 l 5 16 377 0.000
> 125.447 0.830
> -clock.team-cymr 172.16.65.22 2 u 39 64 77 12.989
> -41.044 44.960
> +ntp.okstate.edu .USNO. 1 u 42 64 77 28.906
> -18.762 25.784
> +navobs1.wustl.e .GPS. 1 u 38 64 77 19.133
> 1.819 19.599
> Normally, I just use NMEA with fudge, but that was also showing the
> odd offset so I removed fudge and added the Atom driver to help debug
> (Normally the status shows oPPS(1) but xPPS(1) is seen above for the
> obvious reason.
> ntpd is Dave Hart release 4.2.7p138; I have a serialpps-ppsapi-
> provider.dll dated 6/6/2009.
> Any ideas or recommendations.
You may want to revert to the 3.20 firmware for you GPS 18x LVC - see what
others have written:
and there is a somewhat flawed analysis here:
(flawed in that I was being helped by a UNIX person, and the Windows
driver does not work in exactly the same way as we had assumed).
More information about the questions