[ntp:questions] Bought a GPS receiver--What next?

W. D. NewsGroups at US-Webmasters.com
Mon Nov 1 19:20:41 UTC 2004

Hi Brad,

Thanks for your reply.  More...

Brad Knowles wrote:
> At 4:11 AM -0600 2004-11-01, W. D. wrote:
> >  He says that you need to rebuild the kernel, but others
> >  say that it's possible to get better accuracy if you don't.
> >  What's the real, full story?
>         For FreeBSD, you do not need to rebuild your kernel, if you want
> refclock support in your NTP server.  The kernel should already have
> everything you need in this respect.

OK, how do I implement this?  What should I put in /etc/ntp.conf
to activate this?

> >  Somewhere I read that you need to load the following
> >  driver:
> >
> >     /usr/src/contrib/ntp/ntpd/refclock_oncore.c
>         Right, this would be a natural part of building "ntpd", the NTP
> daemon.  It will need to be built with refclock support for the
> Oncore, which the default standard ntpd provided by FreeBSD may not
> be configured to do.

OK, what is the procedure to build-in Oncore support?  How is 
refclock_oncore.c integrated into the NTP executable programs?

>         Unfortunately, building the version of ntpd in the ports
> subsystem probably won't be configured for refclock support, either.
>         You'll need to download the latest version from
> <http://ntp.isc.org/bin/view/Main/SoftwareDownloads>.  

I am running:

  version="ntpd 4.2.0 at 1.1161-r Tue Oct  5 23:55:53 CDT 2004 (2)"

that's the most recent version, yes?  If it's not configured
for refclock support, how do I do this?

>The tarball
> you download should give you the information you need to build and
> install your own version of ntpd that is properly built to
> incorporate refclock support for your Oncore device.

OK.  I understand that it 'should'.  I am wondering where that it
*DOES*.  I an currently looking at the HTML docs that came
with that version.  Here are some analogous pages on the Web:

Pulse-per-second (PPS) Signal Interfacing

Motorola Oncore GPS receiver

PPS Clock Discipline

Debugging Reference Clock Drivers

Kernel Model for Precision Timekeeping

Also, it is suggested that I need the configuration file:


What is the format of the file--what are the appropriate
commands and settings?  I don't see this documented 
fully anywhere.

Twiki pages are also inscrutable:

I guess if I can't get satisfactory answers to these
questions, I'll just try to slog through Art Neilson's


Again, does anyone know how talk to this unit to find out my 
latitude, longitude and elevation?  How many satellites
it sees?

> --
> Brad Knowles, <brad at stop.mail-abuse.org>
> "Those who would give up essential Liberty, to purchase a little
> temporary Safety, deserve neither Liberty nor Safety."
>      -- Benjamin Franklin (1706-1790), reply of the Pennsylvania
>      Assembly to the Governor, November 11, 1755
>    SAGE member since 1995.  See <http://www.sage.org/> for more info.

Start Here to Find It Fast!™ ->
$8.77 Domain Names -> http://domains.us-webmasters.com/

More information about the questions mailing list