Stick calibration and IMU calibration would be no different in the field. No need to do it anywhere but at home in front of the PC.
In fact it's best to do the IMU calibration at home because it needs to be perfectly level and that's hard to do outdoors.
The IMU calibration has nothing to do with the compass and is not affected by electronics or magnetic fields. It's only about the inertial sensors, the accelerometers and gyroscopes.
It's very important the unit be perfectly level and perfectly still, no movements or big vibrations.