Calibrating the compass on your HoverflyGPS
1. You should start with your HoverflyPRO connected to your HoverflyGPS and your multirotor ready to fly, with the main battery plugged in and ready to arm.
2. The LED on your HoverflyPRO should be blinking green (disarmed) and your HoverflyGPS should not be blinking purple.
3. The calibration should be performed outdoors and at least 10 feet away from buildings, cars, power lines, etc. - anything that could interfere with a magnetic reading. A grass field is best.
4. Your HoverflyPro and HoverFlyGPS should not be connected to your computer
To start the calibration:
1. Move your throttle to its maximum setting and your rudder to its farthest right setting
Your HoverflyPRO will begin to beep and the LED will blink red. This indicates the calibration has been started.
2. With the front of your HoverflyPRO facing north, slowly rotate your multirotor along the pitch axis end over end a few times (more than 360 degrees of rotation)
3. With the front of your HoverflyPRO facing west, slowly rotate your multirotor along the roll axis end over end a few times (more than 360 degrees of rotation)
4. To finish the calibration, move your throttle to its lowest setting.
Your HoverflyPRO will beep again to indicate that the compass calibration is completed.
5. Verify your calibration!!!
It is critical to verify that your calibration was successful by looking for the checkbox as shown below.
6. Check the quality of your calibration.
With the HoverflyGPS connected to the setup client, verify that each cardinal direction is indicated when the multirotor is facing that direction. Confirm that when the multirotor faces north the compass indicates north. Repeat this for south, east, and west. The compass indicator indicates magnetic heading and should match a map compass closely.
If your compass is not indicating the correct direction, repeat the calibration, paying close attention to the instructions and making sure you are away from anything that could cause a magnetic disturbance.
Another common cause for an incorrect compass heading are ferrous materials in your multirotor. This includes steel screws and other hardware - anything that sticks to a magnet. Motor magnets will not cause a disturbance, but your multirotor should not include steel parts.
Sometimes, proximity to ESCs and other equipment can cause the compass to indicate a good heading while on the ground, but an incorrect heading while in the air. To avoid this problem ensure the magnetometer (whether onboard or external) is at least 5 inches from your electronic speed controllers.