DMU380SA Series
User’s Manual
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Doc# 7430-0026 Rev. 01
Page 16
Figure 9.
BIT Configuration
Mag Alignment Procedure
3.12
IMPORTANT
The following section only applies to DMU380SA Series products with magnetometers
(AHRS and INS380SA). If your particular model does not utilize magnetometers for
heading or performance you can disregard Section 3.12.
3.12.1
Hard Iron/Soft Iron Overview
The AHRS and INS380SA products use magnetic sensors to compute heading. Ideally,
the magnetic sensors would be measuring only earth's magnetic field to compute the
heading angle. In the real world, however, residual magnetism in your system adds to the
total magnetic field measured. This residual magnetism (called hard iron and soft iron)
will create errors in the heading measurement if it is not accounted for. In addition,
magnetic material can change the direction of the magnetic field as a function of the input
magnetic field. This dependence of the local magnetic field on input direction is called
the soft iron effect.
