[ntp:questions] NTPD+GPS+PPS

Mikel Jimenez mikel at irontec.com
Wed Jun 17 08:42:28 UTC 2009


Hi

I'm trying to configure ntp for use a usb GPS receiver as time source.

This is the exact model:
http://www.haicom.com.tw/gps204III_USB.aspx

I am new in GPS world, but momentary I do the following:

I have patched a vanilla 2.6.26 kernel with PPS support. I also mark the 
PPS debuging option in the "make menuconfig" and after compiling and 
booting y look this.

miki-iron:/home/miki# tail -f /var/log/syslog
Jun 17 10:39:30 miki-iron kernel: [ 2131.940530] capture assert seq 
#1895 for source 0
Jun 17 10:39:31 miki-iron kernel: [ 2132.996779] PPS event at 400899
Jun 17 10:39:31 miki-iron kernel: [ 2132.996784] PPS event on source 0 
at 1245227971.121624496
Jun 17 10:39:31 miki-iron kernel: [ 2132.996786] capture assert seq 
#1896 for source 0
Jun 17 10:39:32 miki-iron kernel: [ 2134.126201] PPS event at 401149
Jun 17 10:39:32 miki-iron kernel: [ 2134.126205] PPS event on source 0 
at 1245227972.121624683

On the other hand, I have installed the GPSD package and i look that :

miki-iron:/home/miki# gpspipe -r
GPSD,R=1
$GPGGA,084021,4318.8293,N,00258.9451,W,1,07,1.40,-17.35,M,,,*37
$GPRMC,084021,A,4318.8293,N,00258.9451,W,0.0583,210.440,170609,,*3C
$GPGSA,A,3,08,04,07,02,25,10,13,,,,,,0.0,1.4,0.0*3A
$PGRME,0.74,M,0.70,M,0.00,M*1A
$GPGGA,084022,4318.8294,N,00258.9451,W,1,07,1.40,-17.05,M,,,*30
$GPRMC,084022,A,4318.8294,N,00258.9451,W,0.1361,25.760,170609,,*06
$GPGSA,A,3,08,04,07,02,25,10,13,,,,,,0.0,1.4,0.0*3A
$PGRME,0.74,M,0.70,M,0.00,M*1A

I have patched ntpd for PPS support but I am not be able to make ntpd 
integrate with the GPS.

Some ntp.conf examples?
Some ideas?

I have to use NMEA or PPS?
Thanks!!

-- 
Mikel Jimenez Fernandez
Irontec, Internet y Sistemas sobre GNU/LinuX - http://www.irontec.com
+34 94.404.81.82





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