Amazon.com: SparkFun GPS-RTK Dead Reckoning pHAT Compatible with Raspberry Pi-Concurrent Reception of GPS GLONASS Galileo BeiDou High Precision GPS - Receives L1C/A & L2C Bands Voltage:5V or 3.3V Logic:3.3V : Electronics
GPS-RTK Hookup Guide - SparkFun Learn
Don't Be Ripped Off Buying RTK GPS - Discussions - diydrones
GPS-RTK Hookup Guide - SparkFun Learn
Precise GPS GNSS positioning with a Raspberry Pi and the RTKLIB #piday #raspberrypi @Raspberry_Pi « Adafruit Industries – Makers, hackers, artists, designers and engineers!