Dual RTK and Corrected Heading

Hi all!

So curious question.

We fly some pretty intense terrain following and long missions so we have our altitude as GPS altitude with RTK from a base rover module always connected with RTK fixed.

We usually have two RTK units on board, which is fine because I just use the “use best” parameter to select the best data in case of drop outs or failures.

I want to move to GPS heading using a RTK unit with dual antennas like the Holybro dual antenna UM982 or the CUAV RTK 2HP. Both of these use dual antennas spaced min 30cm to derive heading.

If I use one of these modules and my standard RTK unit together, I can foresee an issue where the GPS without dial heading antennas will show RTK Fixed as it is corrected from the ground rover. But also the Heading GPS will also show RTK Fixed as it’s using its other antenna to correct it for heading. But that is a bit misleading as I’m used to RTK fixed being corrected from the ground unit and good for GPS altitude.

So if I move to this setup, I can’t really use the Use best option as it will see RTK Fixed on the dual antenna and think it’s corrected and thus high quality, won’t it?

So my idea of having back up GPS doesn’t really work in this situation. The back up GPS would never be corrected using the ground station and if the autopilot used it our altitude could be out.

Thoughts? I wonder if it’s worth changing the corrected heading status of RTK Fixed to something like RTK heading? Although I’m unsure the system could tell the difference!