I think I finally have my GPS NTP server tweaked. Average deviance yesterday was 0.33ms.
Just threw that last adjustment in, and we’ll see tomorrow how it aligns (eg, am I just -0.33 now, or am I close to 0.03 off?)
Without the time1 offset, it was getting silently ignored. Obscure.
Config is simple once you understand it, but for me, the understanding part was tough.
Quick-Reference:
apt update && apt install gpsd ntp ntpdate
ntpdate time.nist.gov
Plug in the VK* or uBlox style GPS receiver and put it in a window.
dmesg | grep tty
cat <<‘EOF’ >> /etc/default/gpsd
START_DAEMON=”true”
USBAUTO=”false”
DEVICES=”/dev/ttyACM0″
EOF
systemctl disable gpsd.socket
systemctl enable gpsd.service
systemctl restart gpsd.service
cat <<‘EOF’> /etc/ntp.conf
### Public servers and permissions
pool time.nist.gov burst minpoll 5 maxpoll 5
pool us.pool.ntp.org burst minpoll 5 maxpoll 5
pool pool.ntp.org burst minpoll 5 maxpoll 5
server ntp01.frontier.com burst minpoll 5 maxpoll 5
server ntp02.frontier.com burst minpoll 5 maxpoll 5
restrict source notrap nomodify noquery
restrict default kod limited nomodify notrap nopeer noquery
restrict -6 default kod limited nomodify notrap nopeer noquery
restrict 127.0.0.1
restrict -6 ::1
### Stats needed for accuracy
driftfile /var/lib/ntp/ntp.drift
leapfile /usr/share/zoneinfo/leap-seconds.list
statsdir /var/log/ntpstats/
statistics loopstats peerstats clockstats
filegen loopstats file loopstats type day enable
filegen peerstats file peerstats type day enable
filegen clockstats file clockstats type day enable
### GPS time service (PPS does not work on my device)
server 127.127.28.0 minpoll 3 maxpoll 4
fudge 127.127.28.0 time1 0.0445 refid GPS
server 127.127.28.1 prefer minpoll 3 maxpoll 4
fudge 127.127.28.1 refid PPS
broadcast 192.168.1.255 minpoll 4 maxpoll 4
EOF
systemctl enable ntp
systemctl restart ntp
