Multi-Magnetometer Platform Self-Calibration for Heading Accuracy
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Solution Overview
Problem
Conventional magnetometers are significantly influenced by man-made magnetic perturbations in indoor environments, leading to inaccurate heading calculations, as they are not effectively self-calibrated and require physical movement or user assistance.
Innovation Solution
A self-calibrated multi-magnetometer platform with at least two magnetometer triads aligned along the z-axis, which are physically rotated in the xy-plane to measure the Earth's magnetic field, allowing for automatic calibration and perturbation mitigation without user assistance or magnetometer movement, using a combination of host processor, calibration unit, and magnetic heading filter to remove hard-iron and soft-iron components from magnetic field measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional magnetometers are used in indoor environments, then they can provide magnetic field measurements, but the measurements are significantly influenced by man-made magnetic perturbations leading to inaccurate heading calculations
Solution Approach 1:
The system divides the magnetic field measurement task into multiple magnetometer triads (at least two) that are physically rotated relative to each other in the xy-plane. Each triad measures the magnetic field from its specific orientation, and the host processor combines these segmented measurements to compute rotation measurements and detect perturbations, thereby improving heading accuracy in perturbed environments.
Solution Approach 2:
The system implements a feedback mechanism where the host processor continuously monitors magnetic field measurements from multiple rotated triads, detects the presence of magnetic perturbations, and automatically initiates calibration processes. This feedback loop enables the system to adapt to changing magnetic environments and maintain accurate heading calculations despite perturbations.
2Extent of automation
If magnetometers require physical movement or user assistance for calibration, then calibration can be performed, but the system becomes more complex and requires user intervention
Solution Approach 1:
The magnetometer triads are pre-configured in physically rotated positions during manufacturing, establishing the geometric relationships needed for self-calibration. This preliminary arrangement of components enables the system to perform automatic calibration algorithms without requiring user-assisted physical movement during operation, reducing operational complexity while maintaining automation.
Solution Approach 2:
The system implements self-service calibration where the host processor automatically processes measurements from multiple rotated triads to generate rotation measurements, detect perturbations, and calibrate the magnetometers without external user assistance. The calibration unit and magnetic heading filter work autonomously to maintain accurate measurements, eliminating the need for user intervention in the calibration process.
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
Enables accurate and reliable magnetic heading calculations in both clean and perturbed environments by automatically detecting and mitigating magnetic perturbations, providing perturbation-free magnetic field measurements for precise heading determination.
Implementation Method 1
Magnetometers are instruments used for measuring the strength and direction of various magnetic fields such as the earth's magnetic field
Implementation Method 2
The combined magnetic field measurements may be utilized to compute the magnetic heading for the multi-magnetometer device if no magnetic perturbations are detected
Data Source
AI summary
A multi-magnetometer device comprises at least two z-axis aligned and physically rotated magnetometer triads utilized for measuring corresponding earth's magnetic field. The magnetic field measurements are utilized to measure rotation measurements of a single orthogonal axis along the 360 degrees of the complete circle without user's assistance and/or magnetometer movement for magnetometer calibration. The multi-magnetometer device may compute its magnetic heading utilizing the magnetic field measurements if no magnetic perturbations are detected. When magnetic perturbations are detected, a perturbation mitigation process may be performed. The rotation measurements may be generated by selectively combining the magnetic field measurements. Hard-iron components are determined utilizing the rotation measurements, and are removed from the magnetic field measurements. Soft-iron components are determined utilizing the hard-iron free magnetic field measurements, and are removed from the hard-iron free magnetic field measurements. The resulting perturbation free magnetic field measurements are utilized to compute magnetic heading.