Magnetic Sensor Interference Detection for Reliable Orientation Fusion
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Solution Overview
Problem
Magnetic and/or electrical interference in the surrounding area of a magnetic sensor can lead to inaccurate orientation and movement information in sensor systems, which are equipped with both magnetic and inertial sensors.
Innovation Solution
An evaluation device that detects magnetic and/or electrical interference in the surrounding area of a magnetic sensor by comparing sensor signals with predefined deviations and correlation coefficients, allowing for reliable orientation and movement information determination without complex filtering or recalibration, using relatively simple and inexpensive electronics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic field strength distribution is determined to detect interference, then detection capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent introduces an intermediary mathematical model that predicts expected magnetic field strength based on sensor position and orientation. This model acts as a mediator between the magnetic sensor and interference detection, allowing weak interference to be detected by comparing actual measurements with predicted values without requiring complex field strength distribution mapping equipment.
Solution Approach 2:
The patent creates a virtual copy of the magnetic field environment through mathematical modeling. Instead of physically mapping the magnetic field strength distribution with complex equipment, the system generates predicted field values through algorithms that replicate expected field behavior, enabling interference detection with simpler electronics.
2Measurement precision
If complex filtering or recalibration is used to handle interference, then orientation accuracy is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent performs preliminary calibration by determining offset values for the magnetic sensor during a calibration phase. These offset values are stored and automatically applied during normal operation, eliminating the need for complex real-time filtering or frequent recalibration. This preliminary action simplifies the manufacturing process while maintaining orientation accuracy.
Solution Approach 2:
The patent implements a feedback mechanism where the measured magnetic field values are continuously compared with predicted values from the mathematical model. When deviations indicate interference, the system automatically adjusts or discounts the magnetic sensor data, providing continuous feedback-based correction without complex filtering algorithms or recalibration procedures.
3Device complexity
If magnetic sensor data is used without interference detection, then device simplicity is maintained, but reliability of orientation information deteriorates
Solution Approach 1:
The mathematical model serves as an intermediary that enables reliability improvement without increasing device complexity. By comparing actual sensor readings with model-predicted values, the system can detect interference and adjust its reliance on magnetic sensor data, maintaining simple electronics while enhancing orientation information reliability.
Solution Approach 2:
The patent dynamically changes the parameters used for orientation calculation based on detected interference levels. When interference is detected, the system adjusts the weighting or usage of magnetic sensor data versus other sensors (like accelerometers or gyroscopes), changing operational parameters to maintain reliability without adding complex hardware.
Data Source
AI summary
An evaluation device for a sensor system equipped with a magnetic sensor and at least one inertial sensor. The evaluation device includes an electronics device, using which a value of an orientation variable may be determined in view of at least one supplied inertial sensor signal and at least one supplied magnetic sensor signal. Using the electronics device, a comparison value for the at least one orientation variable is determined in view of the inertial sensor signal and in disregard of the magnetic sensor signal. In view of a deviation and/or a correlation coefficient between the value and the comparison value, an information item regarding a reliability of the magnetic sensor signal of the magnetic sensor and/or regarding an occurrence of magnetic and/or electrical interference in a surrounding area of the magnetic sensor, is determined.