Report GPS/Compass in DIY Posted November 7, 2019 I am not sure about those parms as I have never had to change them. What is important though for the compass is the calibration. http://ardupilot.org/copter/docs/common-compass-calibration-in-mission-planner.html I found this to be easier if you place the drone on an office chair that can be rotated. Place it in a box when its upside down. Its also better to do this with the radio telemetry and not using the USB cable.