Magnetic Sensor Calibration Using Position Data
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Solution Overview
Problem
Existing electronic devices with magnetic sensors face calibration challenges due to magnetization from internal components, requiring users to perform burdensome operations to correct azimuth errors, which can result in significant calculation errors if not properly aligned.
Innovation Solution
An electronic device equipped with a magnetic sensor, position acquiring section, and processing unit that acquires specific position information and geomagnetic vectors to calculate an offset value, allowing for automatic calibration without the need for user-induced directional changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If statistical schemes are used to calculate offset values from magnetic data, then calibration accuracy can be improved, but the user burden increases significantly as they must perform specific motions to change the device direction
Solution Approach 1:
The magnetic sensor calibration is performed automatically using the device's own position information from GPS and magnetic field data, without requiring user intervention or specific motions. The processing unit self-calibrates by comparing acquired magnetic data with position information, making the system self-servicing.
Solution Approach 2:
The patent replaces the mechanical approach of manually rotating the device to collect magnetic data with an automatic information-based approach. Instead of requiring physical motion to change sensor orientation, the system uses position information and magnetic field measurements to calculate calibration parameters automatically.
2Ease of operation
If the device direction is kept constant during calibration, then ease of operation is improved, but measurement precision deteriorates as magnetic data concentrates in a specific plane
Solution Approach 1:
The patent introduces position information (GPS coordinates) as an intermediary to resolve the contradiction. Instead of relying on mechanical device orientation to diversify magnetic data collection, the system uses position information as a mediator to acquire and identify unique magnetic field characteristics at different locations, enabling calibration without manual rotation.
3Measurement precision
If manual calibration operations are required to correct azimuth errors, then measurement precision can be maintained, but productivity decreases due to time-consuming user actions
Solution Approach 1:
The system performs preliminary acquisition of position information and magnetic field data during normal device operation, storing this information for later calibration processing. This preliminary data collection enables rapid automatic calibration without requiring users to perform time-consuming manual operations at calibration 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
This solution reduces user burden and improves calibration accuracy by automatically determining the offset value, ensuring accurate azimuth calculations even when the device is not rotated or moved, thus minimizing errors associated with magnetization effects.
Implementation Method 1
a magnetic sensor which detects a magnetic field around the electronic device and outputs magnetic data in accordance with the magnetic field detected by the magnetic sensor
Implementation Method 2
the magnetic sensor mounted on the electronic device may be magnetized by receiving magnetism from an electronic component inside the electronic device and a magnetic field around the electronic device
Data Source
AI summary
An electronic device includes a magnetic sensor which detects a magnetic field around the electronic device and outputs magnetic data in accordance with the magnetic field detected by the magnetic sensor, a position acquiring section which acquires position information regarding a geographic position of the electronic device, and a processing unit. The processing unit acquires, from the position acquiring section, specific position information for a specific position of the electronic device when an output vector of the magnetic data is oriented to a magnetic pole direction of the earth, derives a geomagnetic vector at the specific position based on the specific position information, and acquires an offset value based on a comparison between the geomagnetic vector and the output vector.