When magnetometers are used as heading reference, a magnetic calibration is mandatory for normal sensor operation. Different calibration methods are provided, depending on accuracy or ease of use requirement.

Light Ship calibration (ASV, ROV, AUV)

As long as a vessel is light enough to be held by a few persons (especially unmanned vehicles), a 3D calibration, made on the ground is to be preferred. The basic procedure remains the same, and you should just rotate the system in as much orientations as possible.

Large ship calibration

In case the vessel is a heavy ship and it is not possible to move it by hand, it will be necessary to calibrate the magnetometers while cruising. The goal will be to collect data in every direction, so you will have to make a 360° with the ship (the turn radius and speed does not matter).

You should prefer a 3D calibration if your boat can heel, if not then a 2D calibration should be done.

The following procedure should be followed for good performance:

  1. Install the sensor as described in previous sections, and place the whole system away from external magnetic disturbances (buildings, other vessels , etc)

  2. Press “Start acquisition” button on sbgCenter calibration window

  3. Navigate in an 8 shape pattern, so you will be able to capture points in the Y-axis while heeling slightly on both sides. It doesn’t need to be a critical angle, 20° would be enough for instance, it has to be representative of the usual behavior of the ship.

  4. Check that the 3D method is used (in case of very large ship, or when the roll/pitch angles could not be changed significantly during calibration, a 2D method can be used). Press “ Calibrate ” and check calibration results. Press “ OK ” to finalize the calibration procedure.

  5. Power cycle the sensor if you need immediate operation after calibration.


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