Chrony and gpsd

Based on:

• https://gpsd.gitlab.io/gpsd/gpsd-time-service-howto.html
• https://wiki.alpinelinux.org/wiki/Chrony_and_GPSD
• https://learn.adafruit.com/adafruit-ultimate-gps-hat-for-raspberry-pi/use-gpsd
• https://forums.adafruit.com/viewtopic.php?f=50&t=70133&start=60#p359668

Attempt to build a Stratum 1 server using chrony with gpsd and a GPS module.

• Raspberry Pi 2
• Adafruit Ultimate GPS Hat
• u.FL to SMA adapter
• SMA GPS antenna 5m cable
• Debian 11 for Raspberry from https://raspi.debian.net/
• chrony
• gpsd

Installation

Set timezone

timedatectl set-timezone Europe/Berlin

Disable serial console

systemctl mask serial-getty@ttyAMA0.service

Install base packages

apt install gpsd gpsd-clients python3-gps chrony pps-tools

The serial interface needs to be configured. I haven't figured out yet how to make this persist across reboots:

stty -F /dev/ttyAMA0 raw 9600 cs8 clocal -cstopb

gpsd configuration at /etc/default/gpsd

Devices gpsd should collect to at boot time. # They need to be read/writeable, either by user gpsd or the group dialout. DEVICES="/dev/ttyAMA0" # Other options you want to pass to gpsd GPSD_OPTIONS="-n -D1 -s 9600" # Automatically hot add/remove USB GPS devices via gpsdctl USBAUTO="false"