Multi-Magnetometer Fusion for Heading Estimation Accuracy
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Solution Overview
Problem
Existing magnetometer calibration techniques struggle to accurately account for non-stationary magnetic interferences and component re-magnetization, leading to poor heading estimation in electronic devices.
Innovation Solution
The use of multiple magnetometers and multi-magnetometer fusion techniques to evaluate calibration quality, estimate and eliminate non-stationary disturbances, and perform targeted recalibrations, thereby improving heading estimation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional single magnetometer calibration is used, then device complexity is low, but heading estimation accuracy deteriorates due to non-stationary magnetic interferences and component re-magnetization
Solution Approach 1:
The patent divides the magnetic field measurement function into multiple independent magnetometers within the device. Each magnetometer provides separate measurements that are later combined through fusion algorithms, allowing the system to distinguish between external field changes and internal disturbances, thereby improving heading estimation accuracy while managing complexity through modular architecture
Solution Approach 2:
The patent combines measurements from multiple magnetometers using fusion techniques to produce a single reliable heading estimate. By merging data from multiple sensors and comparing their outputs, the system can identify and reject measurements corrupted by non-stationary interferences or component re-magnetization, achieving higher accuracy than a single magnetometer could provide
2Reliability
If always-on field monitoring is implemented to detect component re-magnetization, then calibration quality control improves, but power consumption increases significantly
Solution Approach 1:
The patent implements periodic calibration quality checks using multiple magnetometers at predetermined intervals rather than continuous monitoring. The system compares measurements from multiple magnetometers at these intervals to detect component re-magnetization events and triggers recalibration only when necessary, maintaining reliability while dramatically reducing power consumption compared to always-on monitoring
Solution Approach 2:
The patent uses feedback from multiple magnetometer comparisons to intelligently control calibration timing. By continuously comparing measurements from multiple magnetometers and detecting deviations that indicate re-magnetization, the system provides feedback that triggers recalibration only when quality degradation is detected, avoiding unnecessary continuous calibration operations and reducing power consumption
3Measurement precision
If multiple magnetometers are used with continuous monitoring, then heading estimation accuracy improves, but power consumption increases due to frequent recalibration requests
Solution Approach 1:
The patent employs periodic measurement comparisons at predetermined intervals rather than continuous monitoring, reducing the frequency of recalibration requests while maintaining the ability to detect and correct calibration quality degradation, thus lowering power consumption while preserving heading estimation accuracy
Solution Approach 2:
The system uses feedback from multi-magnetometer comparisons to trigger recalibration only when quality degradation is detected, rather than performing continuous recalibration. This selective feedback-based approach maintains high accuracy by correcting issues when they arise while significantly reducing power consumption by avoiding unnecessary recalibration operations
4Measurement precision
If traditional calibration procedures are used, then stationary magnetic interferences can be compensated, but non-stationary magnetic interferences cannot be addressed
Solution Approach 1:
The patent transitions from static calibration procedures to dynamic calibration quality control by continuously comparing measurements from multiple magnetometers. This dynamic approach allows the system to adapt to changing conditions including non-stationary magnetic interferences and component re-magnetization events, maintaining calibration accuracy in varying operational environments
Solution Approach 2:
The patent implements feedback-based calibration quality monitoring that detects when non-stationary interferences affect measurements by comparing multiple magnetometer outputs. When deviations indicate non-stationary interference or re-magnetization, the system triggers recalibration to restore accuracy, providing adaptability to interference types that traditional static calibration cannot handle
Data Source
AI summary
Methods, systems, and apparatus, for calibration quality control using multiple magnetometers. One of the methods includes: receiving measurements by two or more magnetic field sensors of a device over a period of time, wherein each measurement measures a magnetic field at each magnetic field sensor, wherein each measurement at each time point over the period of time includes a vector in one or more spatial axes of a three-dimensional space; computing a difference between the measurements over the period of time, wherein the difference at each time point over the period of time is a result of computing a difference based on one or more pairs of the vectors at the time point; determining that the difference does not remain within a predetermined range over the period of time; and in response, classifying calibration quality of the device as unsuitable for computing a heading of the device.