## Using GPSD as Stratum 0/1 time source
## Requires GPS USB Dongle
## Can be used on Raspberry Pi OS or any Debian derivitive
## Tested with Debian 10/11 & RaspberryPiOS Buster & Bullseye
## Tested as of 17 Dec 2021
## Issues: KD9EFV at gmail dot com


sudo apt update && sudo apt upgrade -y

sudo apt install chrony gpsd gpsd-clients -y
sudo nano /etc/default/gpsd
- - - - -
DEVICES="/dev/ttyACM0"  ## Use your GPS Dongle device here
GPSD_OPTIONS="-n -G"
USBAUTO="false"
START_DAEMON="true"
- - - - - 
[ctrl]x y [enter]

sudo sed -i.bak 's/pool/#pool/g' /etc/chrony/chrony.conf
echo "refclock SHM 0 offset 0.5 delay 0.2 refid NMEA" |sudo tee -a "/etc/chrony/chrony.conf"
sudo systemctl restart chrony
chronyc sources -v
Should list the NMEA (GPS Data strings) as a source. I tmay take a few minutes to properly sync up

This setup can be used as a Network Time Server for the local network, too, with a couple of minor
changes in this server setup, and adding the server to the clients. I do so for both home and field operations, Ethernet & WiFi. You can also enable GPS location sharing (gridsquare) for BAP machines
to use.

Kevin -- KD9EFV