Magnetic Calibration Manual
Xsens MTi User Manual Repository
Magnetic Calibration Manual
Copyright © 2021 Xsens Page 29
XDA Start and Stop RepMo mode
using startRepresentativeMotion and stopRepresentativeMotion.
Store the ICC results using storeIccResults. Refer to the XDA
library for more information:
C:Program FilesXsensMT Software Suite x.xDocumentationMT
SDK
During the RepMo mode, the RepMo status bit in the Status Word will be 1. After stopping
RepMo mode, an info dialog will come up (in MT Manager) or a feedback message will be sent
by the filter (low-level communication and XDA), informing you about the results. It will tell
you whether a 2D or 3D calibration was performed. For some applications, such as Ground
Vehicles, a planar 2D calibration suffices. In addition, a score of the "Estimated distortion
level" or 'ddt value' is returned. This value indicates how homogenous the magnetic
environment was during the calibration. The closer the score is to 1, the better. Try
performing multiple calibrations at different locations to see whether your results can be
improved.
Although RepMo is designed to be used without a PC, we will demonstrate the use of RepMo
using MT Manager in the following example.
The results of an MTi 1-series attached to a battery are shown in the figure below. It is
important to note that the magnetic norm (black line in the middle graph) should be constant
if the sensor is properly calibrated and it is moving in a magnetically
homogeneous environment. This is clearly not the case for the first part of the magnetometer
signal. After the initial period of 13 seconds, Representation Motion is switched on for ~25
seconds. This is indicated by the (violet) status bit flag. The user then clicks the "Store In-
Run Compass Calibration results" button in MT Manager to write the calibration results to the
device's memory. Once the results are written to the non-volatile memory, the magnetic
calibration is applied and the magnetic field norm is nearly constant, showing a meaningful
calibration done (for sensor-fixed distortions).
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