3DM-CX5-GNSS/INS
User Manual
30
5.4
Magnetometer Manual Calibration
Although the 3DM-CX5-GNSS/INS magnetometers are calibrated at the factory to remove any internal
magnetic influences in the device, measurements are still subject to influence from external magnetic
anomalies when the sensor is installed. These anomalies are divided into two classes: hard iron offsets
and soft iron distortions. Hard iron offsets are created by objects that produce a magnetic field. Soft iron
distortions are considered deflections or alterations in the existing magnetic field. Ideally, these
influences are mitigated by installing the sensor away from magnetic sources, such as coils, magnets,
and ferrous metal structures and mounting hardware. However, often these sources are hard to avoid
or are hidden.
To mitigate this effect when using the 3DM-CX5-GNSS/INS magnetometer to aid in heading estimations,
a field calibration of the magnetometer after final installation is highly recommended. This can be
accomplished using LORD Sensing MIP Hard and Soft Iron Calibration software. The following are
instructions for field calibrating the magnetometers:
1.
Connect and power on the sensor as normal, and open the MIP Hard and Soft Iron
Calibration software.
2.
Enter the Local Magnetic Field information for the sensor to account for magnetic
influences inherent to the sensor's geographic location on the Earth. As needed, use the
WMM on Web button to access a World Magnetic Model calculator on the British
Geographic Survey website. This site, and similar sites, generate Local Magnitude F
values based on latitude and longitude entries. In the calculator solution, these values
will be found in row MF, column F.
Figure 26. Sensor Menu
