[ntp:questions] fudge time1 for gps-18x-LVC?

David J Taylor david-taylor at blueyonder.delete-this-bit.and-this-part.co.uk.invalid
Sat Feb 6 12:10:14 UTC 2010


"David Lord" <snews at lordynet.org> wrote in message 
news:7t53vhFb3mU1 at mid.individual.net...
[]
> A few us isn't bad from PPS unless I'm supposed to use the -350 ms
> from nmea via RxD.
>
> Note that the PPS via serial and parallel are both converging to
> same < 10us and it's only when serial DCD is disconnected that
> GPS_NMEA shoots off by -350us. PPS via parallel is well within
> spread of the servers on network
>
> ! after 10 hours
> !    remote    refid   st t  reach offset jitter
> ! +GPS_NMEA(0) .GPS.    0 l   377  29.189 21.691
> ! oPPS(0)      .PPS.    0 1   377  -0.009  0.004
> !  serv1       serv2    2 u   377   1.144  0.526
> !  serv2       .INIT.  16 u     0   0.000  0.000
> !  serv3       serv2    2 u   377  -0.018  1.740
[]
> David

OK, I mis-read the table.  If the 9 microseconds is the true offset, 
that's fine (well, it would be for me, anyway).  Do the figures say that 
with PPS on the parallel port, using the ATOM driver, the GPS is then just 
working with serial, and it shows a 29 millisecond offset?

Just to clarify, though, when above you say "disconnecting the DCD" you 
mean leaving the system with no PPS signal, and that's when you see a 
350us offset?

Cheers,
David 




More information about the questions mailing list