[ntp:questions] need help installing gps with ntp on Linux
Ron Frazier (NTP)
timekeepingntplist at c3energy.com
Sat Feb 11 21:09:03 UTC 2012
On 02/11/2012 06:09 AM, Uwe Klein wrote:
> Ron Frazier (NTP) wrote:
>> Hi all,
>> I have recently been posting messages about my experience trying to
>> install a USB GPS and wring out the maximum performance in Windows.
>> Now I need help doing the same thing in Linux. I want to install the
>> GPS using only NTPD if possible, without GPSD, to make my install
>> configuration as close as possible to the way it's set up in Windows.
>> Please let me know if I'm on track or not and why my GPS is not
>> working, if possible.
>> I'm running Ubuntu 11.04 and had already installed NTP version
>> 126.96.36.199.p2 from the Ubuntu Natty repositories. That runs fine,
>> polling from the internet.
>> I plugged in the USB GPS and it appeared as /dev/ttyUSB0. I used the
>> following configuration line to set up the port:
>> From: http://www.satsignal.eu/ntp/Sure-GPS.htm
>> I used: stty -F /dev/ttyUSB0 57600 igncr clocal -echo -ixon
>> Then, I used the following command to set up a symlink to the port:
>> ln -T /dev/ttyUSB0 /dev/gps1 (Actually, I tried gps5 first.)
>> Then, I did cat /dev/gps1 and got the following:
>> ron at asus-k52f-1:/etc$ cat /dev/gps1
>> So, I know the port is working and I know the GPS is putting out data.
>> Before editing the ntp.conf file, I stopped the service using:
>> sudo /etc/init.d/ntp stop
>> These are the GPS lines in /etc/ntp.conf:
>> server 127.127.20.1 prefer minpoll 3 maxpoll 3 mode 72
>> fudge 127.127.20.1 time2 0.3000 refid GPS1
> last year I played around with the Sure Board.
> see http://wiki.tcl.tk/28358
> for me the mode keyword did not work the way it was supposed.(
> baudrate wise )
> check what the baudrate is after ntp has started.
> Look in the log : /var/log/messages or /var/log/ntp/* for errors.
> I am running on SuSE, log destination tend to vary over distributions.
Thanks for the note. I've spent most of the day troubleshooting this.
Your suggestion to check the error logs helped me find a solution. I
found an error by apparmor in the syslog. I'll post the complete
procedure to get it working once I've had a chance to write it up.
Basically, though, I had to edit the apparmor tunable profile for ntpd
to allow ntpd to access /dev/gps1 or /dev/gps5, then restart apparmor,
then restart ntpd. Once I did that, the dominos started falling into
place. I'm now on my way to having a functional system.
(PS - If you email me and don't get a quick response, don't be concerned.
I get about 300 emails per day from alternate energy mailing lists and
such. I don't always see new messages very quickly. If you need a
reply and have not heard from me in 1 - 2 weeks, send your message again.)
timekeepingdude AT c3energy.com
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