Questions about Stabilize and Compass

ArduCopter Copter 3.1
1

Hello, I have some questions that I didn’t found on documentation or in the forum:

  1. In the stabilize mode, the compass is used ? Is compass used on all modes ?

  2. Some people say that you can plug the battery to the ESCs and then use the BEC to power the APM while the APM is plugged on the USB, is that correct and it is possible ? I heard someone saying that it fried the APM. If this is possible, the JP1 jumper must removed or inserted ?

  3. My first flight was a disaster, the quadcopter (X) took off and then it started to fly towards some directions and it was very hard to control, could this be caused by interference on the compass ? Could this be caused by the unbalanced propellers ? I already checked that the motors are spinning right and also that it tries to stabilize when I hold it with my hands.

  4. Is any GPS instrumentation used in Stabilize mode ?

  5. In Stabilize mode, if I just level up the throttle it is supposed to stabilize it self and keep stable hovering ?

Thank you !

2
  1. I believe so, yes. Even in stabilize it helps with yaw.
  2. Why would you want to do that? If APM is plugged into USB, it is powered by USB.
  3. Hard to say. If you post a log, we might see something. Was it windy?
  4. Maybe. If you have geofence enabled, it will use that. Failsafes that go to RTL will need it. You may have a pre-arm check that needs GPS. You really should not fly without good GPS (unless indoors, of course)
  5. Stabilize in APM is not the same as Stabilize on a DJI. In APM it keeps the vehicle axes steady, wind will still push it around. Loiter is more like the DJI “stabilize”.
3

Thank you for the answer !
About the item 2: I want to have battery and USB because I don’t have telemetry and I want to run the compassmot and the motors will need to spin (need battery current). Does this makes sense to you !?

4

I ended using USB together with the battery with the JP1 removed, it worked well and I was able to run compassmot, after that I balanced the propellers and it is now flying well, except for Loiter which is crazy at times but I still have work to do on the magnetometer.

Thanks !