[ntp:questions] need help installing gps with ntp on Linux

Uwe Klein uwe at klein-habertwedt.de
Sat Feb 11 11:09:41 UTC 2012


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 
> 1.4.2.6.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
> $GPZDA,011724.000,11,02,2012,,*54
> $GPZDA,011725.000,11,02,2012,,*55
> $GPZDA,011726.000,11,02,2012,,*56
> $GPZDA,011727.000,11,02,2012,,*57
> $GPZDA,011728.000,11,02,2012,,*58
> $GPZDA,011729.000,11,02,2012,,*59
> $GPZDA,011730.000,11,02,2012,,*51
> $GPZDA,011731.000,11,02,2012,,*50
> 
> 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.


uwe



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