[ntp:questions] Re: ntpd/GPS on Sun: newbie questions

Allen McIntosh mcintosh at nospam.com
Wed Dec 31 23:06:55 UTC 2003


In article <_bednQmjsfyZr26iXTWc-g at speakeasy.net>,
Jonathan <jonathanNOFISH at sprintmail.com> wrote:
>1)  Can the xntpd from Solaris 8+patch 109667-05 (v3-5.93e) support NMEA GPS
>receivers?  It did not seem to work at all when I tried it; only 4.1.1a
>worked.

If the Solaris xntpd contains the string "NMEA GPS Clock", then yes.
If not, then probably not.  (strings xntpd | grep "NMEA")

>2)  What NMEA strings are required/supported in (x)ntpd?  The Sony chipset
>supports $GPRMC, $GPGGA, $GPGLL, and $GPZDA, which I think some or all are
>supported by (x)ntpd?

It's in the comment at the start of refclock_nmea.c.

>3)  Does (x)ntpd rely purely on NMEA data for accurate timekeeping?  I saw
>some posts related to people using PPS with GPS units but I'm not sure I
>understand the connection yet.

As I understand it, the timing on NMEA sentences is significantly sloppier
than the PPS signal.

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