Magnetic Sensor Hard Iron Soft Iron Coefficient Auto-Update
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Magnetic sensors in electronic compassing and motion sensor fusion systems face challenges in accurately updating hard-iron and soft-iron coefficients due to frequent changes and external distortions, leading to inaccuracies and the need for continuous automated calibration.
Innovation Solution
A method that involves measuring magnetic fields during device rotations, determining the quality of new coefficients, and updating existing coefficients only if they provide better accuracy, using a criterion-based system that includes a coefficient estimator and a Kalman filter to track and correct for distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If automated calibration is implemented to continuously update coefficients, then accuracy is improved, but device complexity increases
Solution Approach 1:
The system performs self-calibration by automatically detecting hard-iron and soft-iron distortions during normal device operation. The calibration process occurs in the background without requiring user intervention or external calibration tools, allowing the device to maintain accurate magnetic field measurements while minimizing added complexity.
Solution Approach 2:
The system pre-computes correction coefficients for hard-iron and soft-iron distortions before they significantly degrade measurement accuracy. By continuously monitoring magnetic field data and updating coefficients proactively, the system prevents accuracy degradation rather than reacting to it, reducing the need for complex real-time correction mechanisms.
2Reliability
If continuous coefficient updating is performed, then reliability is improved, but loss of time increases
Solution Approach 1:
The system performs coefficient updates periodically based on detected changes in distortion patterns rather than continuously at fixed intervals. The calibration process is triggered when significant changes in hard-iron or soft-iron distortions are detected, optimizing the balance between maintaining reliability and minimizing processing time overhead.
Solution Approach 2:
The calibration process operates continuously in the background during normal device usage, utilizing otherwise idle processing cycles. By performing coefficient updates during regular device operation rather than requiring dedicated calibration sessions, the system maintains measurement reliability without causing noticeable interruptions or time loss to the user.
3Adaptability or versatility
If calibration is performed during normal usage, then adaptability is improved, but measurement precision deteriorates due to external distortions
Solution Approach 1:
The system extracts and separates the device's internal hard-iron and soft-iron distortion components from external magnetic field distortions during calibration. By identifying and isolating the device-specific distortion signatures, the calibration process can proceed during normal usage without being corrupted by external magnetic anomalies, maintaining both adaptability and precision.
Solution Approach 2:
The system uses intermediary reference measurements and mathematical models to distinguish between device-generated distortions and external environmental distortions. By introducing these intermediary elements in the calibration process, the system can accurately compute correction coefficients even when operating in magnetically complex environments, maintaining precision while adapting to various usage conditions.
Data Source
AI summary
Apparatuses, methods and systems apparatus for automatically updating hard iron and soft iron coefficients of a magnetic sensor of a device are disclosed. One method includes making measurements of a magnetic field by the magnetic sensor during rotations of the device, determining by at least a criterion whether to input the measurements of the magnetic field into a coefficient estimator, calculating, by the coefficient estimator, new hard iron and soft iron coefficients upon receiving the measurements of the magnetic field, determining a quality of the newly calculated hard iron and soft iron calculated coefficients, and updating existing hard iron and soft iron coefficients to the newly calculated hard iron and soft iron coefficients only if the quality of the newly calculated hard iron and soft iron coefficients.