Dual Magnetometer Calibration for Temperature Error Correction
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Solution Overview
Problem
Existing systems for tracking movable objects, such as shopping carts, face challenges in accuracy due to temperature variations and magnetic hysteresis, especially in environments with strong magnetic fields, which affect magnetometer readings and require costly and complex installations.
Innovation Solution
A dual magnetometer system comprising a low-power magneto-impedance magnetometer and a higher-power magneto-resistive magnetometer, where the latter corrects temperature-related errors in the former, allowing dynamic switching to optimize sample rates based on conditions and providing accurate heading data for improved position estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a single low-power magneto-impedance magnetometer is used for tracking, then power consumption is reduced, but measurement precision deteriorates due to temperature variations and magnetic hysteresis
Solution Approach 1:
The patent combines two different magnetometer technologies (magneto-impedance and magneto-resistive) into a single integrated system. The magneto-resistive magnetometer serves as a reference device to correct temperature and hysteresis errors in the magneto-impedance magnetometer, achieving high measurement precision while maintaining low average power consumption through dynamic switching.
2Measurement precision
If a dual magnetometer system with temperature correction is implemented, then measurement precision improves, but device complexity increases
Solution Approach 1:
The system dynamically switches between the two magnetometers based on operational requirements. The processor selectively activates the magneto-resistive magnetometer only when temperature correction is needed, rather than continuously operating both devices, thereby reducing overall system complexity while maintaining high measurement precision when required.
3Productivity
If dynamic switching between magnetometers is implemented, then productivity improves through optimized sample rates, but device complexity increases
Solution Approach 1:
The system implements dynamic switching between magnetometers based on real-time operational conditions and temperature stability requirements. This allows the system to optimize sample rates and processing efficiency by using the appropriate magnetometer for each measurement scenario, improving overall productivity while managing complexity through intelligent control.
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
Enhances the accuracy and reliability of position estimation for movable objects by compensating for temperature and hysteresis effects, enabling precise tracking in various environments without the need for extensive infrastructure, thereby reducing costs and improving system performance.
Implementation Method 1
a second higher-power-consumption magnetometer (e.g., a magneto-resistive magnetometer)
Implementation Method 2
compensation for various error sources involving the use of a magnetometer and accelerometer, and using vibration analysis to derive wheel rotation rates. Also disclosed are various techniques to utilize characteristics of the operating environment in conjunction with or in lieu of dead reckoning techniques
Implementation Method 3
a first, low-power-consumption magnetometer (e.g., a magneto-impedance magnetometer)
Data Source
AI summary
Examples of systems and methods for calibrating or operating a magnetic sensor for sensor temperature or operating conditions are provided. The magnetic sensor can comprise a dual magnetometer sensor that comprises a first, low-power-consumption magnetometer (e.g., a magneto-inductive magnetometer) and a second higher-power-consumption magnetometer (e.g., a magneto-resistive magnetometer). The second magnetometer can have a lower unit-to-unit variation in temperature calibration parameters and can be used to temperature-correct readings from the first magnetometer. The magnetic sensor can dynamically switch between usage of the first magnetometer and the second magnetometer in order to provide a dynamic sample rate that can depend on conditions within the sensor or external to the sensor.