Sensor Calibration Independent of airframe

Hello,

I’m working on building a very large cumbersome drone airframe, and was planning to mount the Pixhawk, GPS and many other electronics on a removable “tray” of sorts. The tray will not have the telemetry radios on it (they are located far from the Pixhawk and GPS), nor ESCs or motors. Would it be possible to calibrate the pixhawk sensors on this small tray independent of the vehicle airframe, and then bolt the tray onto the vehicle afterward? Calibrating the whole vehicle and spinning it around for the compass calibration is very difficult with a vehicle of this size.

I just want to verify, as I found this regarding ardupilot:

http://ardupilot.org/copter/docs/common-magnetic-interference.html

And if those distances are true for the Pixhawk 2 and PX4 I would guess that doing the calibration independently may not end so well.

Thoughts? Has anyone done this before?