Wearable Compass Calibration with Azimuth Error Correction
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Solution Overview
Problem
Electronic devices experience errors in azimuth angle calculations due to geomagnetic disturbances, leading to inaccurate compass functions when moving between environments with and without magnetic interference, such as indoors and outdoors or in vehicles.
Innovation Solution
A wearable electronic device with geomagnetic sensors that perform geomagnetic calibration to acquire geomagnetic data, calculate offsets, determine reference azimuth angles, compensate for errors, and update the reference azimuth angle in memory to provide accurate compass information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If geomagnetic calibration is performed in environments with magnetic disturbances (indoors, in vehicles), then the device can acquire compass information, but the azimuth angle contains large errors (30-100 degrees) due to noisy magnetic data
Solution Approach 1:
The patent implements dynamic calibration mode switching between static and moving modes. The static calibration mode is used in stable environments (outdoors) to achieve high precision, while the moving calibration mode is used during transitions (indoors/outdoors, in vehicles) to maintain operational availability. This dynamic adaptation resolves the contradiction by selecting the appropriate calibration approach based on environmental conditions.
Solution Approach 2:
The patent changes calibration parameters including the number of samples collected, calibration duration, and weighting factors based on detected environmental conditions. When magnetic disturbances are detected (indicating indoor or vehicle environments), the system adjusts calibration parameters to prioritize operational continuity over precision, whereas in stable environments, it uses parameters optimized for accuracy.
2Adaptability or versatility
If the device performs calibration in magnetically disturbed environments, then it can provide compass information, but the reliability of the azimuth angle information decreases significantly
Solution Approach 1:
The patent performs preliminary calibration in stable outdoor environments before the device enters magnetically disturbed environments (indoors or vehicles). By completing calibration beforehand when magnetic conditions are good, the system stores reliable baseline data that can be used during subsequent disturbed periods, thus maintaining reliability while adapting to different environments.
Solution Approach 2:
The system continuously monitors magnetic field conditions and provides feedback to determine when calibration results are reliable. When disturbances are detected, the system adjusts its behavior based on this feedback, such as avoiding calibration or using alternative reference data, thereby maintaining reliability across varying environmental conditions.
3Duration of action of moving object
If the device uses gyro sensor for azimuth calculation, then it can provide direction information, but integration errors accumulate over time reducing accuracy
Solution Approach 1:
The patent merges gyro-based continuous tracking with periodic geomagnetic calibration. The gyro sensor provides continuous short-term direction changes with high response, while geomagnetic sensors provide periodic long-term reference updates. This combination allows the system to maintain both continuous operation capability and long-term precision by correcting gyro drift through occasional geomagnetic realignment.
Solution Approach 2:
The system maintains continuous azimuth tracking using gyro data while periodically refreshing the reference frame using geomagnetic calibration. This ensures uninterrupted direction information (continuity) while periodically correcting accumulated errors (precision), resolving the trade-off between continuous operation and measurement accuracy over time.
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
The device provides highly reliable magnetic information and accurate compass information by correcting azimuth angle errors in magnetically disturbed environments, ensuring precise navigation.
Implementation Method 1
a sensor that detects geomagnetism by measuring the voltage value induced by geomagnetism using a flux-gate
Implementation Method 2
a sensor that detects rotational angular velocity by measuring the Coriolis Force
Data Source
AI summary
A wearable electronic device is provided. The wearable electronic device includes a display, a sensor configured to detect geomagnetism and acquire geomagnetic data, memory storing one or more computer programs, and one or more processors communicatively coupled to the display, the sensor, and memory, wherein the one or more computer programs include computer-executable instructions that, when executed by the one or more processors individually or collectively, cause the wearable electronic device to acquire an azimuth angle on the based on geomagnetic data, acquire a plurality of offsets based on the geomagnetic data when geomagnetic calibration is executed, acquire a reference azimuth angle based on the plurality of offsets, acquire an azimuth angle error based on a uniformity of the plurality of offsets, acquire a new reference azimuth angle by compensating for the azimuth angle error with the reference azimuth angle, and update the new reference azimuth angle in the memory.