3-axis Magnetometer Array Calibration via Aggregate Parameter Determination
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Solution Overview
Problem
Calibrating arrays of 3-axis magnetometers in complex geometries and environments is challenging due to manufacturing variability, packaging errors, and environmental changes, which affects the accuracy and reproducibility of magnetic field measurements in ferromagnetic material analysis.
Innovation Solution
A system and method for calibrating arrays of 3-axis magnetometers that determine scale factor, bias, and orientation using a combination of uniform and non-uniform magnetic fields generated by Helmholtz coils and a dipole magnet, allowing for accurate positioning and compensation for irregular geometries and changes over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual magnetometers are calibrated separately, then each magnetometer can be optimized, but the calibration time and complexity increase significantly for large arrays
Solution Approach 1:
The patent combines multiple individual magnetometer calibrations into a single aggregate calibration process. By treating the array of magnetometers as a unified system with a shared coordinate system, the method determines scale factors, biases, and orientation parameters for all magnetometers simultaneously rather than calibrating each one separately, thereby reducing total calibration time while maintaining accuracy.
Solution Approach 2:
The patent implements a universal calibration approach where a single calibration procedure serves all magnetometers in the array. The method uses a common set of reference measurements and coordinate system transformations that can be applied uniformly across the entire array, making the calibration process scalable to any array size without proportionally increasing time or complexity.
2Adaptability or versatility
If magnetometers are positioned in arbitrary geometries, then the system can adapt to complex structures, but positioning and orientation determination becomes more difficult
Solution Approach 1:
The patent transforms the calibration problem from determining absolute positions and orientations to determining relative parameters within a shared coordinate system. By changing the reference frame and using relative position vectors between magnetometers, the method simplifies the mathematical complexity while maintaining the ability to handle arbitrary geometries and curved surfaces.
Solution Approach 2:
The patent introduces a shared coordinate system as an intermediary framework that connects all magnetometers in the array. This coordinate system acts as a mediator that simplifies the relationship between magnetometers in arbitrary positions, allowing the system to handle complex geometries without proportionally increasing calibration complexity.
3Ease of manufacture
If packaging errors and alignment variations occur, then manufacturing is easier, but measurement accuracy decreases
Solution Approach 1:
The patent applies preliminary anti-action by measuring and characterizing the actual positions and orientations of magnetometers during calibration, then using these measured parameters to compensate for packaging and alignment errors. Rather than trying to prevent errors during manufacturing, the system measures the errors and mathematically compensates for them in the calibration data.
Solution Approach 2:
The patent uses feedback by measuring the actual magnetic field responses from known reference sources and using these measurements to determine and correct position and orientation parameters. The system continuously refines the calibration parameters based on measured data, compensating for manufacturing variations through iterative optimization.
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 reproducibility and efficiency of calibration, enabling precise determination of magnetic field values and maintaining consistency over extended periods, critical for detecting gradual changes and anomalies in ferromagnetic materials.
Implementation Method 1
detecting a uniform magnetic field at each of the 3-axis magnetometers for different orientations of the array relative to the magnetic field
Implementation Method 2
The present method and system further utilize a source of non-uniform magnetic fields within or near the array to determine magnetometer position information
Data Source
AI summary
A system and method for calibrating rigid and non-rigid arrays of 3-axis magnetometers. Such arrays might be used to analyze structures containing ferromagnetic material. The calibration determines scale factor and bias parameters of each magnetometer in the array, and the relative orientation and position of each magnetometer in the array. Once the parameters are determined, the actual magnetic field value at the magnetometer location can be simply related to magnetometer measurements. The method and system can be used to calibrate an array of 3-axis magnetometers in aggregate as opposed to individual magnetometers. This is critical in large arrays to increasing reproducibility of the calibration procedure and decreasing time required to complete calibration procedure.