I do have that as well, but haven't done a write up on it yet. It was a $70 GPSDO from eBay (BH3SAP variant running Fredzo firmware with some changes to enable flywheel (generating pulse in absence of GPS PPS)). I have verified it can feed the Pi for NTP. Believe the STM32 driving the GPSDO can as well but it has no ethernet capability as-is