Calibration method and device for carrying it out
AssigneeAmfitech ApS
InventorsJørn Eskildsen, Lau Kofoed Kierstein
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Abstract
Electromagnetic tracking systems and methods for automatically providing the required additional information needed to identify the orientation of a sensor are disclosed. The tracking systems are configured to carry out a digital modulation process to determine one or more parameters needed for calibration and to determine if the carrier wave and the modulated signal are in-phase or 180° out-of-phase at time T=0, thereby determining the operational sign of the carrier wave and thus the orientation of the one or more sensors. In some embodiments, at least one offset coil is arranged to generate an additional magnetic field, and the tracking system may be calibrated on the basis of the additional magnetic field.
Claims20
A three-dimensional alternating current electromagnetic field tracking system for determining the position and orientation of an object, wherein the tracking system comprises:
- an electromagnetic field transmitter comprising three coils configured to generate three magnetic fields;
- one or more electromagnetic field receivers (sensors) each comprising three measurement coils;
- and
- a control unit,
- wherein the tracking system is configured to carry out a digital modulation process to determine one or more parameters needed for calibration, wherein the digital modulation process is a phase-shift keying (PSK) modulation process modulating a phase of a constant frequency carrier wave, wherein the tracking system is configured to determine if the constant frequency carrier wave and the phase modulated signal are in-phase or 180° out-of-phase at time T=0, thereby determining an operational sign of the constant frequency carrier wave and thus the orientation of the one or more sensors.
A method for automatic calibration of a three-dimensional alternating current electromagnetic field tracking system comprising an electromagnetic field transmitter comprising three coils configured to generate three magnetic fields, one or more electromagnetic field receivers each comprising three measurement coils, and a control unit, the method comprising:
- carrying out a digital modulation process to determine one or more parameters needed for calibration, wherein the digital modulation process is a phase-shift keying (PSK) modulation process modulating a phase of a constant frequency carrier wave;
- and
- determining if the constant frequency carrier wave and the phase modulated signal are in-phase or 180° out-of-phase at time T=0, thereby determining an operational sign of the constant frequency carrier wave and thus the orientation of the one or more sensors.
Dependencies are inferred from the claim text.