30
Document MT1600P.2019.A
© Xsens Technologies B.V.
MTi Family Reference Manual
using gravity (i.e. by using the accelerometers). In a homogeneous magnetic field, the gyroscope bias
around the z-axis can be successfully estimated as well by monitoring the direction of the magnetic field.
The magnetic field can be distorted by the presence of ferromagnetic materials, permanent magnets or
power lines with strong currents (several amperes) in the vicinity of the device. The distance to the object
and the amount of ferromagnetic material determines the magnitude of disturbance introduced. If the
local Earth magnetic field is temporarily disturbed, the on-board filters will initially track this disturbance
instead of incorrectly assuming that the device has rotated. However, in case of continuous magnetic
disturbances (>10 to 30 s, depending on the filter settings) the computed heading will slowly converge
to a new solution using the 'new' local magnetic north. Note that the magnetic field has no direct effect
on the inclination estimate.
In the special case that the MTi is rigidly strapped to an object containing ferromagnetic materials,
constant magnetic disturbances will be present. Using a so-called 'magnetic field mapping' (MFM, i.e. a
3D calibration for soft and hard iron effects), these magnetic disturbances can be completely calibrated
for, allowing the MTi to be used as if it would not be secured to the object containing ferromagnetic
materials.
For more information please review the
Magnetic Calibration Manual
14
.
14
Links to the latest available documentation can be found via the following link:
