I just built one of these. It's fun to have a little computer that can synchronize highly accurate time without an internet connection by listening to things in outer space!

I built an auto-install script that anyone here is welcome to use or reference[1]. If you know what you're doing, just change the GPIO pin to your PPS input and fire away.

Unlike the author I used Chrony instead of NTP. It's lighter-weight and much easier to configure with a PPS/GPS reference clock.

The GPS chip I used was an ATGM336H, which can be had for less than $8 on ebay. I'm able to lock consistently 11 satellites from my desk[2]

Keep in mind the Pi has no hw RTC. If you're doing this for fun spend a few more bucks and buy an rtc chip from ebay so you don't drift considerably between being powered off.

1. https://github.com/stephen-mw/raspberrypi/blob/master/roles/...

2. https://www.ebay.com/sch/i.html?_from=R40&_nkw=ATGM336H&_sac...