Magnet Position Tracking with Magnetic Disturbance Identification
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Solution Overview
Problem
Existing magnet tracking systems face challenges in accurately estimating the position of a magnet relative to a network of magnetometers due to magnetic disturbances, which can lead to deterioration in tracking precision and algorithm convergence issues.
Innovation Solution
A method that identifies and accounts for magnetic disruptors by calculating an indicator parameter from the difference between estimated and measured magnetic fields, using a Bayesian recursive estimation algorithm or optimization algorithm to update the magnet's state vector, and optionally filtering the indicator to minimize the impact of dynamic movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a network of magnetometers is used to track the magnet position, then the tracking capability is provided, but magnetic disturbances in the vicinity cause degradation of tracking precision
Solution Approach 1:
The patent segments the magnetic field analysis into two distinct components: the useful magnetic field generated by the tracked magnet and the parasitic magnetic field from disturbances. By calculating the gradient of the magnetic field and identifying directions with maximum variation, the system separates the signal of interest from background interference, allowing precise position estimation even in disturbed environments.
Solution Approach 2:
The patent converts the harmful effect of magnetic disturbances into a beneficial detection mechanism. By analyzing deviations between measured and expected magnetic field gradients, the system not only maintains tracking accuracy but also identifies the presence and location of magnetic disturbers. The disturbance signature becomes a detectable anomaly that can be filtered or compensated for in the tracking algorithm.
2Measurement precision
If magnetic disturbance identification is added to the tracking system, then tracking precision is improved, but system complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the measured magnetic field is continuously compared with the expected field based on the current position estimate. The deviation between measured and expected gradients provides feedback about both position errors and disturbance presence. This feedback loop allows the system to iteratively refine position estimates while detecting anomalies, achieving enhanced precision without requiring completely separate detection systems.
Solution Approach 2:
The patent makes the tracking algorithm multi-functional by enabling it to simultaneously perform position estimation and disturbance detection using the same magnetometer network and computational framework. The gradient analysis and deviation calculations serve dual purposes: refining position estimates and identifying magnetic disturbers. This universal approach avoids adding separate hardware or algorithms, managing complexity while providing multiple functions.
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
This approach enhances the accuracy of magnet position estimation by differentiating magnetic disruptor effects from model errors, improving tracking precision and ensuring algorithm stability even in the presence of disturbances.
Implementation Method 1
a network of magnetometers capable of measuring a magnetic field
Data Source
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AI summary
The invention relates to a method for estimating the position of a magnet (2) using a tracking device comprising an array of magnetometers, the method comprising phases of determining an initial state vector associated with the magnet, of measuring a useful magnetic field, of estimating a magnetic field, of calculating a bias beween the measured magnetic field and the estimated magnetic field, and of updating the state vector on the basis of the bias. It also comprises an identifying phase comprising a step of identifying a magnetic disturbance on the basis of an indicator calculated depending on an estimated magnetic field and a measured magnetic field.