https://docs.emlid.com/reach/ardupilot-integration/
Since ReachView version 0.3.0 Reach supports RTK-enhanced coordinates output to Navio2, Edge, and Pixhawk autopilots. To make this possible, we implemented a custom GPS protocol ERB (Emlid Reach Binary protocol).
The new product is https://emlid.com/reach/
Here is a demo video with our results: