Fluxgate Magnetometer Offset Elimination via Analog Switching
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Solution Overview
Problem
Fluxgate magnetometers used in space missions face significant offset issues due to time, temperature, mechanical stress, and electromagnetic environment changes, which affect data accuracy and reliability, especially in interplanetary missions where manual calibration is not feasible.
Innovation Solution
A method and device that utilize analog switches to change switch direction combinations and acquire magnetic field data, allowing for the calculation of offset data based on influence factors such as residual magnetism and signal imbalances, without requiring specific external conditions or additional instruments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual calibration is used to eliminate offset, then measurement precision is improved, but ease of operation deteriorates in interplanetary missions
Solution Approach 1:
The fluxgate magnetometer performs self-calibration by automatically switching between different winding configurations (direct winding, reverse winding, auxiliary winding) and computing offset corrections using measured data from multiple states. This eliminates the need for manual intervention, making the system self-sufficient for offset elimination in interplanetary missions where manual calibration is impossible.
Solution Approach 2:
The calibration process periodically switches between different winding states and measurement configurations to gather data needed for offset computation. By periodically alternating between direct and reverse winding modes, the system accumulates sufficient measurement data to calculate and apply offset corrections automatically.
2Measurement precision
If satellite rotation method is used to eliminate offset, then measurement precision is improved, but adaptability deteriorates due to specific external conditions
Solution Approach 1:
The patent replaces the mechanical rotation method with an electrical/winding-based calibration approach. Instead of physically rotating the satellite to change orientation relative to magnetic field sources, the system electrically switches between different winding configurations (direct, reverse, auxiliary) to achieve the same calibration objective, thereby eliminating dependence on satellite rotation capability.
Solution Approach 2:
The calibration method uses the fluxgate magnetometer's own windings for multiple purposes: both for normal magnetic field measurement and for offset calibration. By utilizing the existing direct and reverse windings (and optionally auxiliary windings) for dual functions, the system eliminates the need for external calibration conditions or additional instruments.
3Measurement precision
If additional magnetic field measuring instruments are carried for calibration, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The fluxgate magnetometer's windings serve dual purposes: normal measurement function and calibration function. The direct winding, reverse winding, and auxiliary winding are used both for measuring magnetic fields and for performing offset calibration, eliminating the need for separate calibration instruments and reducing overall system complexity.
Solution Approach 2:
The calibration functionality is merged with the measurement functionality by using the same sensor elements (windings) for both purposes. The system combines offset elimination and magnetic field measurement into a single integrated operation, avoiding the need for separate calibration instruments.
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 approach effectively eliminates offset in fluxgate magnetometers with minimal hardware modification and low cost, suitable for various environments, enhancing data accuracy and reliability for interplanetary equipment.
Implementation Method 1
Fluxgate magnetometer is the main instrument of satellite in-orbit magnetic field measurement, which can measure three-component space vector magnetic field
Implementation Method 2
controlling the first analog switch, the second analog switch and the third analog switch to change directions within a preset period to obtain eight switch direction combinations
Data Source
AI summary
An offset data acquisition method and device of a fluxgate magnetometer are provided by the present disclosure, wherein the offset data acquisition method of the fluxgate magnetometer comprises: controlling the first analog switch, the second analog switch and the third analog switch to change directions within a preset period to obtain eight switch direction combinations between the first analog switch, the second analog switch and the third analog switch; acquiring magnetic field measurement data corresponding to an each of the switch direction combinations; and the magnetic field measurement data comprises x-axis magnetic field measurement data, y-axis magnetic field measurement data and z-axis magnetic field measurement data; and acquiring the offset data based on influence factors of an offset and the magnetic field measurement data within the preset period.