[ntp:questions] why does ntp refuse my pps source
folkert
folkert at vanheusden.com
Sun Jul 14 18:40:25 UTC 2013
Hi,
I have a raspberry pi with a adafruit gps module.
This RPI runs linux with a kernel adapted for PPS.
This is time4:
remote refid st t when poll reach delay offset jitter
==============================================================================
*time1.intranet. .PPS. 1 u 475 1024 377 0.539 0.336 0.282
+time3.intranet. .PPS. 1 u 1014 1024 377 0.961 0.198 0.195
+time2.intranet. 192.168.64.2 2 u 452 1024 377 1.726 0.037 0.198
-auth1.xs4all.nl 134.221.205.12 2 u 779 1024 377 18.207 -2.128 0.191
xSHM(0) .NMEA. 0 l 9 16 377 0.000 -348.89 12.214
xPPS(0) .PPS. 0 l 10 16 377 0.000 0.354 0.002
ind assid status conf reach auth condition last_event cnt
===========================================================
1 29160 961a yes yes none sys.peer sys_peer 1
2 29161 941a yes yes none candidate sys_peer 1
3 29162 9414 yes yes none candidate reachable 1
4 29163 9314 yes yes none outlyer reachable 1
5 29164 911a yes yes none falsetick sys_peer 1
6 29165 9114 yes yes none falsetick reachable 1
associd=29165 status=9114 conf, reach, sel_falsetick, 1 event, reachable,
srcadr=PPS(0), srcport=123, dstadr=127.0.0.1, dstport=123, leap=00,
stratum=0, precision=-20, rootdelay=0.000, rootdisp=0.000, refid=PPS,
reftime=d58d6c66.ffe7320f Sun, Jul 14 2013 20:28:54.999,
rec=d58d6c67.8bdeabe2 Sun, Jul 14 2013 20:28:55.546, reach=377,
unreach=0, hmode=3, pmode=4, hpoll=4, ppoll=4, headway=0, flash=00 ok,
keyid=0, offset=0.378, delay=0.000, dispersion=0.233, jitter=0.010,
filtdelay= 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00,
filtoffset= 0.38 0.38 0.38 0.37 0.37 0.36 0.36 0.36,
filtdisp= 0.00 0.24 0.48 0.72 0.96 1.20 1.44 1.68
I find this rather strange.
Time1 is a regular pc with a garmin 18x lvc, time3 is an rpi with pps.
Time2 is also an rpi with a adafruit gps with pps but using a userspace
pps implementation instead (which might explain why it chooses a remote
time source over its local pps).
Any ideas?
Folkert van Heusden
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