Sensor Parasitic Loop Compensation in Magnetic Tracking
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Solution Overview
Problem
Existing Electromagnetic Tracking (EMT) systems face challenges in accurately determining the position of tracked devices due to distortions in the magnetic signal caused by metallic objects in the environment.
Innovation Solution
The proposed magnetic tracking system includes a sensor configured to generate a sensor electromotive force (EMF) that measures a magnetic field, with a mechanism to select between two operating modes to compensate for signal distortions. This system uses a processing device to compare measurements from both modes, allowing it to determine an approximate value of the sensor EMF and thereby improve positioning accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor is used to measure magnetic field for position tracking, then position information can be obtained, but parasitic EMF generated by interconnecting circuits causes measurement errors and reduces accuracy
Solution Approach 1:
The patent extracts and separates the parasitic EMF component from the total measured signal. By using a measurement circuit that can distinguish between sensor EMF and parasitic EMF, the harmful parasitic component is isolated and can be compensated for separately, thereby improving measurement precision without requiring physical removal of the interconnecting circuits
Solution Approach 2:
The patent implements a feedback mechanism where the measured parasitic EMF is fed back into the position calculation process. The system continuously monitors the parasitic EMF generated by interconnecting circuits and uses this information to correct the position measurement in real-time, maintaining accuracy despite the presence of harmful electromagnetic interference
2Measurement precision
If visual markers are placed around the environment to establish a reference frame for compensating magnetic distortions, then compensation for metallic objects can be achieved, but system complexity and cost increase
Solution Approach 1:
The patent enables the magnetic tracking system to self-correct for distortions by having the sensor device itself measure and compensate for parasitic EMF. Instead of requiring external visual markers or environmental reference frames, the system uses its own measurement capabilities to identify and correct errors, thereby maintaining precision without increasing system complexity
Solution Approach 2:
The patent changes the measurement parameters by selectively measuring EMF under different conditions (with and without parasitic influence). By varying the measurement state and comparing results, the system can extract accurate position information while compensating for distortions, avoiding the need for additional physical markers or complex environmental setup
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively compensates for magnetic signal distortions, leading to more accurate determination of the position of tracked devices, even in environments with metallic objects.
Implementation Method 1
a sensor configured to generate a sensor electromotive force (EMF) that measures a magnetic field that is generated by a magnetic field transmitter
Implementation Method 2
an interconnecting circuit configured generate a parasitic EMF in each of the first operating mode and the second operating mode when receiving the magnetic field
Data Source
AI summary
A magnetic tracking device includes a sensor configured to generate a sensor electromotive force (EMF). The device includes a mechanism configured to select between a first operating mode in which the sensor generates the sensor EMF when receiving the magnetic field and a second operating mode in which the sensor generates a reduced amount of the sensor EMF when receiving the magnetic field. An interconnecting circuit generates a parasitic EMF in each of the first operating mode and the second operating mode. The interconnecting circuit connects to a processing device which receives a first measurement for the first operating mode, the first measurement representing the sensor EMF and the parasitic EMF, receives a second measurement for the second operating mode, the second measurement representing the parasitic EMF, compares the first measurement and the second measurement, and determines an approximate value of the sensor EMF.