Continuous Magnetometer Calibration for Heading Accuracy
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Solution Overview
Problem
Conventional magnetometer calibration procedures in mobile devices require user intervention and are not continuous, leading to inaccuracies due to environmental magnetic interference and the need for repeated manual calibration.
Innovation Solution
A system and method for continuous magnetometer calibration using a processor circuit that continually performs measurements, determines the device state, and updates a calibration model based on accuracy evaluations, employing algorithms like linear and nonlinear least squares fits to correct for hard and soft iron distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional manual magnetometer calibration procedures are used, then calibration can be performed, but user involvement is required and calibration is not continuous leading to inaccuracies
Solution Approach 1:
The system performs self-calibration by automatically detecting device states and updating calibration models without user intervention. The processor continuously monitors magnetometer data and autonomously determines when calibration is needed, eliminating the need for users to manually initiate calibration procedures.
Solution Approach 2:
The calibration process transitions from discrete manual operations to continuous automatic updates. The system continuously evaluates magnetometer measurements against the calibration model and performs incremental updates whenever accuracy thresholds are breached, ensuring uninterrupted calibration effectiveness.
2Reliability
If conventional manual magnetometer calibration procedures are used, then calibration can be performed, but repeated manual calibration is required when error exceeds threshold
Solution Approach 1:
The system implements continuous feedback by monitoring magnetometer measurement accuracy against the calibration model. When measurements deviate beyond predefined thresholds, the system automatically triggers recalibration, creating a closed-loop system that maintains consistent accuracy without user awareness of the process.
Solution Approach 2:
The system performs preliminary calibration actions by continuously updating the calibration model in the background before accuracy degradation becomes apparent to the user. This proactive approach prevents navigation errors rather than reacting to them after they occur.
3Measurement precision
If manual calibration is performed in locations with significant error sources, then calibration can be completed, but accuracy is compromised due to environmental interference
Solution Approach 1:
The calibration system dynamically adapts to environmental conditions by continuously monitoring measurement quality and adjusting calibration updates in real-time. Rather than requiring static, controlled calibration environments, the system learns to compensate for varying magnetic interference through ongoing operational data.
Solution Approach 2:
The system converts environmental magnetic interference, which traditionally degrades calibration accuracy, into useful information for continuous model refinement. By continuously exposing the calibration model to varied environmental conditions and automatically adapting, the system learns to distinguish between genuine navigation signals and environmental noise.
Data Source
AI summary
A method for performing continuous calibration of a magnetometer in a device includes during operation of a device, continually performing magnetometer measurements; continuously determining a state of the device; determining a magnetometer calibration model based on the magnetometer measurements and the state of the device; continually evaluating an accuracy of the magnetometer calibration model based the magnetometer measurements and the state of the device; and updating the magnetometer calibration model based on the evaluation of the accuracy magnetometer calibration model, the magnetometer measurements, and the state of the device.