RPi/install/NTP_server_using_GPS_receiver/README.md

In this project we shall setup NTP-server on Raspberry using GPS-receiver connected to serial port.

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2020 05 26 + init chrony@rpi /A

2022 03 19 + published on https://github.com/InstallAndUse/RPi /A

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getting time from gps

apt install gpsd gpsd-clients python-gps nano /etc/default/gpsd

DEVICES="/dev/ttyAMA0"
GPSD_OPTIONS="-n"

systemctl enable gpsd && systemctl restart gpsd systemctl status gpsd

add serial device (BT uses another one)

nano /boot/config.txt

dtoverlay=pi3-miniuart-bt
core_freq=250

shutdown -r now

test

cgps -s gpsmon -n

setting up NTP server

apt install chrony #? systemctl enable chronyd && systemctl restart chronyd systemctl status chronyd chronyc sources -v nano /etc/chrony/chrony.conf

# comment for setup, uncomment on finish (to keep for time comparison)
pool 2.fedora.pool.ntp.org iburst
pool 2.debian.pool.ntp.org iburst
# add NMEA source as time reference
refclock SHM 0 offset 0.5 delay 0.2 refid NMEA

systemctl restart chronyd chronyc sources -v

test

ntpshmmon

set up NTP server

nano /etc/chrony/chrony.conf

allow 192.168.0.0/16

systemctl restart chronyd

test

chronyc

clients
serverstats

clean and remove ntpdate

apt remove ntpdate

Remove ntp-servers from

nano /etc/dhcp/dhclient.conf

# remove "request ntp-servers"
# remove "option ntp_servers"

rm

/etc/dhcp/dhclient-exit-hooks.d/ntp
/lib/dhcpcd/dhcpcd-hooks/50-ntp.conf
/var/lib/ntp/ntp.conf.dhcp (might not exist)

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refs: https://gpsd.gitlab.io/gpsd/gpsd-time-service-howto.html#_feeding_chrony_from_gpsd

http://www.unixwiz.net/techtips/raspberry-pi3-gps-time.html

Books:

• Anton's bookshelf