Magnetic Sensor Self-Calibration via Internal Field Generation
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Solution Overview
Problem
Existing magnetic sensor devices struggle to easily measure and correct for main- and cross-axis sensitivities in varying environments, requiring external input of linearly independent magnetic field vectors, which can be difficult to achieve post-shipment.
Innovation Solution
Integration of multiple magnetic sensors and field generators within the device, along with a correction processor, to generate additional magnetic fields and determine correction functions for signal correction, allowing for in-device measurement and adjustment of sensitivities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external magnetic field vectors are input for sensitivity measurement, then main-axis and cross-axis sensitivities can be measured, but the measurement process becomes difficult to perform after shipment in various environments
Solution Approach 1:
The magnetic sensor device performs sensitivity measurement using its own magnetic field generating coils instead of requiring external magnetic field input. The device generates additional magnetic fields internally and measures the detection signals to calculate main-axis and cross-axis sensitivities autonomously, eliminating the need for external equipment or complex setup procedures.
2Measurement precision
If multiple magnetic sensors are used to detect magnetic field components in multiple directions, then measurement capability is improved, but individual differences in main-axis sensitivity between sensors cause measurement errors
Solution Approach 1:
The device measures the actual main-axis sensitivity of each magnetic sensor using its own generated magnetic fields and uses this measurement feedback to correct detection signals. By calculating correction coefficients based on measured sensitivities and applying them to the detection signals, the system compensates for individual differences between sensors and improves measurement reliability.
3Measurement precision
If sensitivity correction is implemented to account for individual differences, then measurement accuracy improves, but the device requires complex correction processing
Solution Approach 1:
The magnetic sensor device autonomously performs sensitivity measurement and correction coefficient calculation using its own magnetic field generating coils and detection sensors. The correction processor automatically calculates correction coefficients based on measured detection signals and applies them to correct the detection signals, eliminating the need for external correction equipment or complex manual calibration procedures.
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
Enables easy measurement and correction of main- and cross-axis sensitivities within the device, regardless of the environment, without the need for external input of magnetic field vectors, improving accuracy and adaptability.
Implementation Method 1
An example of the magnetic detection element is a magnetoresistive element
Implementation Method 2
a first magnetic field generator capable of generating a first additional magnetic field; a second magnetic field generator capable of generating a second additional magnetic field
Data Source
AI summary
A magnetic sensor device includes three magnetic sensors for detecting components of an external magnetic field that are in three directions, a magnetic field generation section, and a correction processor. The magnetic field generation section generates additional magnetic field components in three directions used for measurements of main- and cross-axis sensitivities of the three magnetic sensors. The correction processor corrects respective detection signals of the three magnetic sensors on the basis of the measurement results of the main- and cross-axis sensitivities of the magnetic sensors.