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Connecting Second Compass

Hi, I’ve added a GPS to the ROV that I am building, and I would like to incorporate the compass that comes with it, especially as the built-in compass seems to wander a good bit.

The GPS works fine, but the compass does not. How can I fix this?

What gps do you have?

What do you mean? How do you know?

Its the Here GNSS, I believe its based of a Ublox m8n. The gps connects and shows my position, but the compass does not.

  • What do you mean the compass does not show your position? The readings from both compasses will be fused into a single reading, the compass in QGC will look the same, but just more accurate.
  • What have you checked to determine whether or not the compass is working?
  • Have you done any additional configuration to let the autopilot know there is an external compass connected?

When looking at the vehicle configuration page it says the second and third compasses are not installed, nor have I had to do any additional calibration.

What sort of configuration should be done to have would need to be done to let the autopilot know that there is an external compass?

So I still haven’t made any progress. Nothing indicates that the second compass is being read. In QGroundcontrol, under the vehicle summary it reads that only the first compass is ready, and that compass 2 and 3 are not installed. Why is this the case?

The compass should be autodetected.

Can you send a parameter file to me and a picture of how everything is wired up?

Here you go:

vehicle.params (19.4 KB)

Please change COMPASS_USE2 parameter to ‘enabled’.

It still says that compass 2 and 3 are not installed.


I did that.

Ok, I’m not sure what the problem is. I’ve ordered a gps/compass to test.

Great, thank you so much!

I believe the compass inside this module does not have driver support in the stable ArduSub software. It will be available in the 3.6 release, which is not currently scheduled. Sorry for the inconvenience.

Got it. Do you know if it supported by Ardurover? The vehicle that I am building is a USV built on the vectored thruster configuration that is supported on Ardusub, and I am thinking of switching over to Ardurover to take greater advantage of the autonomous features supported.

yes rover has support.

Hi @jwalser,

I need to connect a second compass for solving heading drift problem at full throttle, due to magnetic interference caused by the large dc currents of ESC.

Could you please tell me, which compasses are supported with ArduSub v3.5.3?

I have tried GY-273 HMC5883L (module) with no success?

Best wishes.