Multiple GNSS receivers and mag issue

PX4 Autopilot
1

Hello,

I use Holybro UM982 and CUAV Neo3 with my CUAV X7+ Flight Controller.

Whichever of the two GPS/Mags is connected at GPS2/UART4 (6-pin) port is detected as having an orientation of Roll=180, Yaw=90, for its magnetometer, even if the other reveiver is not connected at all! It seems that proper orientation is read only if I use GPS1 port (10-pin)!

I ‘d love to hear your insights.

I don’t care as much as for the mag as I am worried about the second GPS not working properly (haven’t tested yet).

P.S - Running 1.15.4

2

When you do the mag calibration, doesn’t it guess the orientation but allow you to set it manually if it’s wrong?

3

It does so. Setting the correct orientation gives “compass inconsistency” and keeping the automatic one, gives fluctuating readings.

I contacted Holybro and I got an answer which I am not sure I can compehend:

Make sure to calibrate the compass when adding an external magnetometer to the flight controller. If you are still experiencing a compass issue, try using a demagnetizer on the GPS with a built-in magnetometer.

4

I would have to individually figure out the orientation of all the mags involved to know for sure what orientation they are in. And then I’d need to see the airframe to check for any disturbances. It’s hard to say what’s wrong without seeing the airframe (make sure to avoid buzzers close to mags as they can be magnetic). And also, I assume you are calibrating outside away from magnetic interference such as concrete with rebar.

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5

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