System Clock Synchronization

THIS METHOD IS NO LONGER USED

The following process should be used to synchronize the system clock.

1. Ensure that the following are installed:

• gpsd
• gpsd-clients
• chrony

2. Ensure that the following pins for PC Side RS232 (Male) are wired as such:

• Pin 5 (Ground pin) gets ground
• Pin 2 (RX pin) gets TX signal
• Pin 1 (DCD pin) gets PPS signal

3. In the chrony.conf file from the wave lab, change the reference clock lines to match their github instructions. Additionally:

• copy chrony.conf into /etc/chrony/chrony.conf.
• ttySX should be changed to be the correct port.
• refclock SHM 0 refid GPS poll 3 filter 100 offset 0.088 noselect
• refclock SOCK /var/run/chrony.ttySX.sock refid PPS poll 3 trust

4. Terminal commands for syncing (run all as sudo, change ttySX to correct port)

• killall -9 chronyd gpsd ldattach
• chronyd -f /etc/chrony/chrony.conf
• sleep 2
• gpsd -n /dev/ttySX
• sleep 2
• ldattach 18 /dev/ttySX

5. For debugging, you can run sudo gpsmon in terminal to check that GPRMC NMEA string & PPS are both being registered

Author: Nick Charron

Last Edited: 18 Feb 2019