Calibrate Your Accelerometers (optional)
You will be asked to place the plane so that the autopilot board is level, on its right side, left side, nose down, nose up and on its back, hitting any key when it has been repositioned each time. It is important that you hold the plane still when you hit the key each time. This can be hard to do with the size and shape of many planes, so is best done with the board before you mount it in the plane. [/quote]
The wiki says autopilot board but MP says plane. Wiki even suggests to do the calibration without the plane, eg. before mounting the board. Isn’t the plane orientation what counts here, since the APM might not be mounted completely level? Related to this: http://ardupilot.com/forum/viewtopic.php?f=98&t=10239
I’ve always calibrated so the plane/quad is level as it generates offsets in the parameters so the apm thinks it’s level when the craft is level.
Yeah, that’s what I was thinking as well. Do you know if the calibration is made every time when APM boots, so I should keep the plane level at that point? And the calibration option in Mission Planner is just to redo this process without having to cycle power?
The acceleromters are done once using the mandatory setup options in mission planner as described in the wiki. Should only need to do this once when you first put everything together but if you move the apm at all in the airframe then you should redo the calibration.
Every time you power up the apm it does a gyro calibration and it needs to be left perfectly still while this is going on, should only be a few seconds.
Thanks, that clears it up.