USB GPS receiver as reference clock

[Bo Granlund]

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