USB GPS receiver as reference clock

[Bo Granlund]

Hello,

Nikolay Denev [niki at totalterror.net] wrote:
> Bo Granlund wrote:
> >Hi,
> >
> >I have in my posession a Globalsat BU-353 GPS receiver that I would like to
> >use as a NMEA time reference with Freebsd ntpd. The device identifies with
> >freebsd as:
> >
> >ugen0: Prolific Technology Inc. USB-Serial Controller, rev 1.10/3.00, addr 
> >2
> >
> >I'm running 6.2-RC1. I have tried to search with google for hints howto
> >configure this device with ntpd. I have the following /etc/ntp.conf:
> >
> >------8<--------8<--------8<--------8<
> >enable stats monitor pps
> >server 127.127.20.1
> >driftfile /etc/ntp/ntp.drift
> >logconfig +clockall
> >------8<--------8<--------8<--------8<
> >
> >As far as I understand this 127.127.20.1 uses nmea and tries to open
> >/dev/gps1 device for NMEA output. What device file should I link /dev/gps1
> >to, and if it doesn't exist, how do I create it?
> >
> >Any hints will be greatly appreciated. I hope this is not simply a matter 
> >of
> >RTFM since I have searched the net quite extensively for any hints. :)
> >
> >kind regards,
> >Bo Granlund
> 
> Try to load the uplcom(4) module. Probably this will get your USB GPS 
> receiver identified as USB Serial port /dev/cuaU[0-9]

I loaded the uplcom module and reattached the gps receiver. And then I
linked /dev/cuaU0 to /dev/gps1. Cat'ing /dev/gps1 returns NMEA data, but
when I try start ntpd this comes to the logs:

Nov 25 10:58:24 battleangel ntpd[798]: refclock_nmea: time_pps_create
failed: Inappropriate ioctl for device

Do you have any clue as to why it complains about an inappropriate ioctl?

Thanks for the uplcom pointer, now I got somewhat forward in my attempts to
make ntpd work with my usb receiver.

kind regards,
Bo Granlund