Suggestion of good RPi GPIO-compatible GPS Receiver for NTP?

Hello! I’m looking for a good GPIO-compatible GPS receiver to set up a Stratum-1 server on premises here with an RPi. I’m finding threads from 2018 about good receivers, but looking for someone with recent experience with these cards on the ‘best options’ for cards. It’ll be connected to an RPi device - either an RPi 400 (which is here at my desk right now!) or with an RPi that’s going to be arriving in a few days (on order!)

So, looking for anyone’s suggestions for a GPIO RPi compatible GPS receiver.

(Solder-less solutions preferred!)

Just look for a GPSHAT.
Most of them will use a µBlox Chipset and those are fine (ex: Raspberry Pi GPS/RTC Expansion Board)

  • Just add the PPS DTB Overlay
  • configure GPSD
  • add the GPSD SHM driver to your ntp / chrony conifg

I think SatSignal is one of the best sites where you can read about that stuff :slight_smile:

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I used an Adafruit Ultimate GPS with the PPS signal on a GPIO port with a raspberry pi. You can get the breakout board or the hat. The same units are on Amazon if Adafruit is out of stock.

You can also get a stratum 1 ntp server using a Navisys GR701W. It’s a USB gps that is specially made (by Navisys only) so that the GPS Pulse Per Second (PPS) pin is brought through the USB cable and communicates directly with the linux kernel. Its the simplest aproach to getting a stratum 1 and requires no soldering and can be used with a desktop PC or raspberry pi.

I got tired of all the wires on my desk with the RPi and Adafruit Ultimate GPS so migrated to the Navisys unit. It’s running on my daily driver serving thousands of clients a day. Accuracy locally is closer to 10-20 microseconds rather than the 10-20 nanoseconds. It’s a solid stratum 1.

GPSD describes how to feed GPS time to Chrony or ntpd.