On 28/12/2013 20:40, Adrian P wrote:
Hi,
How do I know that my NTP server is actually using the PPS signal from
my Garmin GPS 18x LVC?
I have the following NMEA driver configured in /etc/ntp.conf:
server 127.127.20.0 mode 1 minpoll 4 maxpoll 4 prefer
fudge 127.127.20.0 flag1 1 flag2 0 flag3 1 refid PPS
The below output shows me that NTP is using the NMEA GPS clock,
however I cannot find anywhere a command that tells me that PPS signal
is used as well...
root@debian:~# ntpq -c clockvar
associd=0 status=00f1 , 15 events, clk_no_reply,
device="NMEA GPS Clock",
timecode="$GPRMC,202549,A,xxxx.2257,N,xxxxx.2075,E,000.0,195.2,281213,004.8,E,A*1D",
poll=13, noreply=36, badformat=0, baddata=0, fudgetime1=0.000, stratum=0,
refid=PPS, flags=5
root@debian:~#
Many thanks,
Adrian
Adrian,
My understanding is that a "o" as the tally code in the output from ntpq
-pn indicates PPS sync. On the two systems here fed from a GPS 18 LVC,
with some line omitted:
FreeBSD PC Pixie:
server 127.127.20.1 mode 0 minpoll 4 maxpoll 4 prefer
fudge 127.127.20.1 flag1 1 flag3 1 refid PPS
C:\Users\David>ntpq -crv -pn pixie
associd=0 status=041f leap_none, sync_uhf_radio, 1 event,
stale_leapsecond_values,
version="ntpd [email protected] Sat Dec 28 16:28:47 UTC 2013 (1)",
processor="i386", system="FreeBSD/8.2-RELEASE-p6", leap=00, stratum=1,
precision=-19, rootdelay=0.000, rootdisp=1.000, refid=PPS,
reftime=d66a36ed.19d84794 Sun, Dec 29 2013 5:51:41.100,
clock=d66a36ed.b372d389 Sun, Dec 29 2013 5:51:41.700, peer=32026, tc=4,
mintc=3, offset=0.007628, frequency=28.823, sys_jitter=0.001907,
clk_jitter=0.003, clk_wander=0.007, tai=35, leapsec=201207010000,
expire=201312010000
remote refid st t when poll reach delay offset
jitter
==============================================================================
o127.127.20.1 .PPS. 0 l - 16 377 0.000 0.008
0.002
_____________________________________
Windows 2000 PC Bacchus:
server 127.127.22.1 minpoll 4 # atom PPS driver
server 127.127.20.1 minpoll 4 # NMEA serial Garmin GPS 18LVC
fudge 127.127.20.1 refid NMEA
C:\Users\David>ntpq -crv -pn bacchus
associd=0 status=01ff leap_none, sync_pps, 15 events,
stale_leapsecond_values,
version="ntpd [email protected] Jan 18 13:50:53 (UTC+01:00) 2013 (5)",
processor="x86", system="Windows", leap=00, stratum=1, precision=-18,
rootdelay=0.000, rootdisp=1.030, refid=PPS,
reftime=d66a370c.88361a9d Sun, Dec 29 2013 5:52:12.532,
clock=d66a370e.e893b45c Sun, Dec 29 2013 5:52:14.908, peer=34194, tc=4,
mintc=3, offset=0.001361, frequency=-5.945, sys_jitter=0.047802,
clk_jitter=0.054, clk_wander=0.001, tai=35, leapsec=201207010000,
expire=201212280000, ctr_frequency=4.19
remote refid st t when poll reach delay offset
jitter
==============================================================================
o127.127.22.1 .PPS. 0 l 3 16 377 0.000 0.001
0.048
+127.127.20.1 .NMEA. 0 l 1 16 377 0.000 -0.051
0.041
_____________________________________
and one fed from a GPS 18x LVC, Windows PC Stamsund:
server 127.127.22.1 minpoll 4 # PPS using serialpps.sys
fudge 127.127.22.1 refid PPS flag3 1
server 127.127.20.1 minpoll 4 mode 33 # 19200bps, NMEA serial port
fudge 127.127.20.1 refid NMEA
C:\Users\David>ntpq -crv -pn stamsund
associd=0 status=011f leap_none, sync_pps, 1 event, stale_leapsecond_values,
version="ntpd [email protected] Dec 28 16:04:29.64 (UTC-00:00) 2013 (1)",
processor="x86", system="Windows", leap=00, stratum=1, precision=-22,
rootdelay=0.000, rootdisp=1.225, refid=PPS,
reftime=d66a375c.3e52fa96 Sun, Dec 29 2013 5:53:32.243,
clock=d66a376b.d26fb21b Sun, Dec 29 2013 5:53:47.822, peer=46859, tc=4,
mintc=3, offset=0.088931, frequency=-6.839, sys_jitter=0.034536,
clk_jitter=0.026, clk_wander=0.001, tai=35, leapsec=201207010000,
expire=201312010000
remote refid st t when poll reach delay offset
jitter
==============================================================================
o127.127.22.1 .PPS. 0 l 15 16 377 0.000 0.089
0.035
+127.127.20.1 .NMEA. 0 l 14 16 377 0.000 0.021
0.018
_____________________________________
I hope that helps!
--
Cheers,
David
Web: http://www.satsignal.eu
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