Need help with NMEA + PPS refclock

[Brandon Applegate]

Hello all,

So previously - I had Debian 11 or 12 (?) and ntp.org ntpd built from
source (NOT ntpsec).  I was running refclock type 20 here - and using
"integrated" PPS (i.e. I only had one source/refclock).  This worked like a
charm for years.  Very steady, single digit usec offsets etc.

I just reinstalled this machine with Debian 13 and I am trying to use the
Debian ntpsec package(s) and am having a lot of trouble.

It seems like the two refclocks I need to use (well maybe just one of them
?) are nmea and pps.  Reading the docs it seems that I can do what I used
to have and "integrate" PPS into nmea and just have one source ? (Bonus
question: If that is true, and I were to do that, is there an ntpq command
that would verify that PPS is being used properly ?  Or would the source be
prefixed with an 'o' in the billboard ?)

It also seems that I can have an nmea + PPS source and these will work in
concert.

I currently have:

refclock pps unit 2 minpoll 4 maxpoll 4 ppspath /dev/pps2
refclock nmea prefer minpoll 4 maxpoll 4 mode 1 baud 4800 path /dev/gps0
flag4 1

Which gets me:

root at jetway:/etc/ntpsec# ntpq -pn
     remote                                   refid      st t when poll
reach   delay   offset   jitter
=======================================================================================================
xPPS(2)                                  .PPS.            0 l    9   16
 377   0.0000 158.7602   0.0340
xNMEA(0)                                 .GPS.            0 l   12   16
 377   0.0000   0.3310   0.0525

Again, my hardware is solid.  My NMEA output is good, as well as PPS (GPS
location sanitized):

root at jetway:/etc/ntpsec# cat < /dev/gps0
$GPRMC,224921.000,A,0.0,N,0.0,W,000.2,328.9,120825,05.2,W*53

$GPRMC,224922.000,A,0.0,N,0.0,W,000.2,328.9,120825,05.2,W*58

$GPRMC,224923.000,A,0.0,N,0.0,W,000.2,328.9,120825,05.2,W*53

root at jetway:/etc/ntpsec# ppswatch /dev/pps2
trying PPS source "/dev/pps2"
found PPS source "/dev/pps2"
timestamp: 1755038482, sequence: 1859, offset: -57088441
timestamp: 1755039046, sequence: 1860, offset: -58500396
timestamp: 1755039046, sequence: 1860, offset: -58500396
timestamp: 1755039047, sequence: 1861, offset: -58614668
timestamp: 1755039047, sequence: 1861, offset: -58614668
timestamp: 1755039048, sequence: 1862, offset: -58567599
timestamp: 1755039048, sequence: 1862, offset: -58567599

Can someone point me in the right direction here ?  I figured I'd have some
bumps getting this to work with ntpsec, but I didn't think it would be this
hard.

Thanks.
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