[sgtnoodle]

Two receivers in the same general location tend to see the same atmospheric distortion, so a naive solution for demonstration purposes can still work well assuming the receivers mostly use the same satellites. No need to make an experiment for fun more complicated than you want to, although filters can be fun!

As others have mentioned, There's much better you can do if you're going for optimal and you have the raw satellite timing information from both receivers.

You can go to the extreme and build a full blown IMU that's tolerant to GPS outages. If it's sensitive enough, you can even measure the rotation of the planet. Big expensive ships presumably have that. The boats on a tracker that glitch their orientation when stopped seemingly don't have that, or at least don't have it integrated with that tracking system.