Use a compass GPS instead internal compass

Dear all,
My name is Stéphane, I m working on GPS. I have created a new gps very accurate and knows his attitude, heading, velocity and its MOTION. However I would totally disable the internal compass of Navio and use only those calculated by our GPS (use the value of a frame gps (reserve) and allocated to the compass value) but I difficult to get my bearings in the code of navio. Can you steer me? or tell me find a document assembling the various calls. I have the same problem for the altitude, I would disable the barometer and user the GPS altitude whitout altitude error.
thank you in advance for your help

I’m assuming you’re running the default APM build when I say this, but if you open mission planner and click initial setup, there is a tab that says “Compass”. There you set up your compasses and their offsets. Simply disable the internal and enable your own, then perform the calibration. For the barometer, you’ll have to look at the full parameter list in mission planner. I think there is a setting to use GPS only, but I’m not positive.

There is the compass setting. I didn’t see the barometer setting, but I may have overlooked it.

Thank you a lot for your answer but I try this procedure before and I have a strong reaction.
I saw in Mission Planner than the compass move around always.
Do you know this reaction.
I think i must to do a new build. What do you mean ?Best regards