Reference : https://blog.networkprofile.org/gps-backed-local-ntp-server/https://austinsnerdythings.com/2021/04/19/microsecond-accurate-ntp-with-a-raspberry-pi-and-pps-gps/ Commande : sudo apt updatesudo apt upgrade -ysudo raspi-config ( serial port enabled ) sudo apt install gpsdsudo apt install gpsd-clientssudo apt install pps-toolssudo apt install chrony sudo bash -c « echo ‘# the next 3 lines are for GPS PPS signals’ >> /boot/config.txt »sudo bash -c « echo ‘dtoverlay=pps-gpio,gpiopin=18’ >> /boot/config.txt »sudo bash -c « echo…