Snapdragon calibration: external GPS/MAG still required?


I’m wondering if it’s still true that I need to have both an external GPS and Magnetometer with Snapdragon. There were some posts on the px4users Google group a couple months ago regarding this and how QGroundControl would fail to calibrate the sensors without the external hardware. I’m currently having the same problem.

I’ve got an external GPS (only) and made it through the Compass and Gyro calibration steps but I’m getting stuck on the Accelerometer. When I try to calibrate the accelerometer, I’m getting errors from the mini-dm such as

“error: unable to communicate with the hmc5883 mag sensor”

and px4> says things like

  • “WARN [navigator] navigator: global position timeout”
  • and then “Fatal error on the ADSP!”
  • and "ADSP subsystem failure reason: " (with no text for the reason),
  • and finally, “ERROR [muorb] ERROR: Getting Bulk data from fastRPC link”.

The QGroundcontrol screen stays in the first orientation (yellow, “hold still”) for the accelerometer and never progresses past that.


You won’t need an external magnetometer because the internal mag in the MPU9250 is now working, however it is generally recommended to use an external mag that can be separated from motor currents, etc.

Right now, you will need an external GPS if you want do fly anything autonomous or in POSCTL.

I can reproduce the crash, this seems to be a bug. And it also happens with external GPS/mag.
Thanks for reporting this, I created an issue to track it:

Thanks, I’ll keep my eye on that issue for updates.