Austin writes hands-on tutorials about precise timekeeping with Raspberry Pi, GPS, NTP and PTP, plus home lab and flight simulator projects.
HN commenters recommend his GPS-disciplined NTP write-up for home time servers and point to his Python X-Plane autopilot series.
It is certainly not to the same levels of accuracy as the capabilities provided by the board presented here, but I recently put together a stratum 1 NTP server (there are lots of various instructions online for setting up something like this [0][1]) on my LAN using a Raspberry Pi 4 and a GPS module with PPS output [2]. The setup took a bit of fiddling and experimentation to get working reasonably well (and it still has some glitches when trying to initially sync the time after a reboot), but once it's synced it does track time from GPS very reliably.
For anyone who might be looking for a reliable, accurate NTP time server but isn't interested in the hassle of setting up and configuring the hardware/software themselves, there's also this little appliance [3] I am also using that does something very similar at a great price point (no affiliation here; just a very happy customer). I have both my RPi setup and the NTP200 appliance tracking each other on the same LAN, and they generally agree on the time to within single-digit microseconds, which I think is about as good as one can get with any NTP setup on an Ethernet LAN, at least without resorting to more exotic things like OCXOs, hardware timestamping, etc.
[0] https://austinsnerdythings.com/2021/04/19/microsecond-accurate-ntp-with-a-raspberry-pi-and-pps-gps/
[1] https://www.jacobdeane.com/iot/2020/building-a-gps-based-time-server/
[2] https://www.adafruit.com/product/746
[3] https://centerclick.com/ntp/
I've got a small Raspberry Pi clone set up with a GSP module running chronyd[2], advertised via DHCP as mentioned by GP. Didn't take much time or effort.
I also added a RTC module so it could hold reasonable time during power-loss but I haven't had a chance to verify that it works as expected.
[1]: https://www.aliexpress.com/item/1005001623104119.html The 7M and M8N are both much better than the 6M, regardless get a module with PPS output pin, not all have it. And grab an active antenna, you'll probably need it.
[2]: https://austinsnerdythings.com/2021/04/19/microsecond-accurate-ntp-with-a-raspberry-pi-and-pps-gps/
Sigh Yep. Dunning-Kruger effect specimens hammer out puff pieces to get their participation awards.
Meanwhile, here's some other articles:
NTP: https://austinsnerdythings.com/2025/02/14/revisiting-microsecond-accurate-ntp-for-raspberry-pi-with-gps-pps-in-2025/
PTP: https://austinsnerdythings.com/2025/02/18/nanosecond-accurate-ptp-server-grandmaster-and-client-tutorial-for-raspberry-pi/
https://www.jeffgeerling.com/blog/2025/diy-ptp-grandmaster-clock-raspberry-pi
If you're looking to setup a GPS-disciplined time-server at home, I highly recommend this writeup: https://austinsnerdythings.com/2025/02/14/revisiting-microsecond-accurate-ntp-for-raspberry-pi-with-gps-pps-in-2025/
In the author's latest post he also sets up a pi as PTP grandmaster: https://austinsnerdythings.com/2025/02/18/nanosecond-accurate-ptp-server-grandmaster-and-client-tutorial-for-raspberry-pi/
And I wrote one in Python to climb/turn as well! And to navigate to any of the built-in X-Plane navaids -
https://austinsnerdythings.com/2024/04/06/adding-track-following-direct-to-with-cross-track-error-to-the-python-x-plane-autopilot/
and the first post in the series -
https://austinsnerdythings.com/2021/10/15/creating-an-autopilot-in-x-plane-using-python-part-1/
I think the most interesting thing on this page is the blog post at the bottom of how it was deployed on a VPS using docker compose (https://austinsnerdythings.com/2023/11/01/using-github-actions-to-deploy-a-flask-nginx-cloudflared-tunnel-docker-compose-stack/)