Magnetic Sensor Array with Error Selection for Weak Field Detection
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Solution Overview
Problem
Current magnetic field measurement technologies face challenges in accurately detecting very weak magnetic fields due to high costs, complex installation requirements, and poor linearity in input/output characteristics, particularly with SQUID sensors and current sensors using the magnetoresistance effect element.
Innovation Solution
A measurement apparatus comprising a three-dimensionally arranged magnetic sensor array capable of detecting magnetic fields in three axial directions, which includes error calculation and selection processes to exclude measurement values with high detection errors, and employs feedback magnetic fields to improve linearity and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a SQUID sensor is used to detect very weak magnetic fields, then magnetic sensitivity is improved, but device complexity and cost increase due to requirements for liquid helium and large-scale magnetic shield rooms
Solution Approach 1:
The patent replaces expensive, complex SQUID sensors with cheaper magnetoresistance effect element sensors that do not require liquid helium or large magnetic shield rooms. While individual magnetoresistance sensors have limitations, the system uses multiple sensors arranged in an array to achieve the required measurement precision without the high cost and complexity of SQUID technology
Solution Approach 2:
The patent divides the measurement function across multiple magnetoresistance effect element sensors arranged in an array, with each sensor detecting magnetic fields in specific directions. By segmenting the measurement task across multiple simpler sensors rather than using a single complex SQUID sensor, the system achieves comparable measurement capability with reduced complexity and cost
2Device complexity
If a current sensor using the magnetoresistance effect element is used, then device complexity is reduced and magnetic sensitivity is improved, but measurement precision deteriorates due to poor linearity of input/output characteristics
Solution Approach 1:
The patent introduces feedback coils that generate feedback magnetic fields to cancel out environmental magnetic fields and stabilize the operating point of the magnetoresistance effect elements. This feedback mechanism linearizes the input/output characteristics by compensating for non-linear effects and drift, thereby improving measurement precision while maintaining the simplicity of the magnetoresistance sensor approach
Solution Approach 2:
The feedback coils serve multiple functions: they cancel environmental magnetic fields, stabilize the operating point of the sensors, and improve linearity. This multi-functionality allows the system to achieve high measurement precision using simple magnetoresistance sensors without requiring complex additional components
3Measurement precision
If multiple measurement values are collected from a magnetic sensor array, then measurement precision can be improved, but device complexity increases due to the need for error calculation and data selection processes
Solution Approach 1:
The patent implements self-service through automated error calculation and measurement value selection processes. The system automatically calculates detection errors for each measurement value, compares them against predetermined thresholds, and selects appropriate values without requiring complex external processing or manual intervention. This automation reduces processing complexity while maintaining high measurement precision
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 apparatus effectively detects weak magnetic fields with improved linearity and accuracy, reducing costs and complexity by using a magnetoresistance effect element with feedback magnetic fields to enhance sensor performance.
Implementation Method 1
a current sensor using the magnetoresistance effect element
Implementation Method 2
the effect of an environmental magnetic field is cancelled out using a feedback coil
Data Source
AI summary
A measurement apparatus is provided, which includes a magnetic sensor array formed by three-dimensionally arranging a plurality of magnetic sensor cells each including a magnetic sensor, and capable of detecting an input magnetic field in three axial directions; a measurement data acquiring section that acquires a plurality of measurement values based on the input magnetic field detected by the magnetic sensor array; a magnetic field calculating section that calculates the input magnetic field based on the measurement values; an error calculating section that calculates a detection error of the input magnetic field, based on the plurality of measurement values and a calculation result obtained by calculating the input magnetic field; and a measurement data selecting section that selects a plurality of measurement values to be used for calculating the input magnetic field by the magnetic field calculating section, from among the plurality of measurement values, based on the detection error.