Magnetometer Calibration Using Theoretical Magnetic Field Data
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for calibrating heading reference systems on vehicles, such as aircraft and ships, are complex and inaccurate due to the lack of utilization of theoretical magnetic field properties of the Earth, requiring multiple repositioning and not accounting for hard iron disturbances effectively.
Innovation Solution
The method involves using actual magnetometer readings and theoretical magnetic components of the Earth's magnetic field, obtained from websites, to calculate calibration values for magnetometers at specific headings, providing a universal average gain and offset for the heading system, which can be filtered to reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple repositioning methods are used for calibration, then measurement accuracy is improved, but device complexity and time consumption increase
Solution Approach 1:
The patent changes the calibration approach from spatial repositioning to temporal parameter comparison. Instead of moving the vehicle to multiple positions, the method compares actual magnetometer readings with theoretical magnetic field values at a single position, using parameter differences to determine calibration values. This resolves the contradiction by maintaining accuracy through theoretical comparison while eliminating the complexity of multiple repositioning operations.
Solution Approach 2:
The patent introduces theoretical magnetic field values as an intermediary reference standard. These theoretical values, obtained from external sources, serve as a mediator between the actual magnetometer readings and the calibration process. This intermediary enables accurate calibration without requiring physical repositioning, thus reducing procedural complexity while maintaining measurement precision.
2Measurement precision
If multiple repositioning methods are used for calibration, then measurement accuracy is improved, but time consumption increases
Solution Approach 1:
The method transforms the calibration process from a spatial procedure requiring multiple positions to a temporal comparison of magnetic field parameters. By comparing actual readings with theoretical values at a single position, the calibration can be completed quickly without the time-consuming process of moving the vehicle through multiple orientations, thus resolving the time-accuracy tradeoff.
Solution Approach 2:
The patent uses pre-calculated theoretical magnetic field values that have been determined in advance for various locations. This preliminary preparation of reference data eliminates the need for time-consuming field measurements at multiple positions during the actual calibration process, significantly reducing calibration time while maintaining accuracy through comparison with pre-established theoretical standards.
3Measurement precision
If theoretical magnetic field properties are utilized, then calibration accuracy is improved, but dependency on external data sources increases
Solution Approach 1:
The patent employs theoretical magnetic field values from external sources as an intermediary reference. These pre-computed values from organizations like NOAA serve as a reliable mediator that provides accurate reference data without requiring complex on-site measurement equipment or procedures. The external data source acts as a trusted intermediary that simplifies the overall system while improving calibration accuracy.
Solution Approach 2:
The method uses copied or replicated theoretical magnetic field data from external authoritative sources rather than generating original measurement data. By copying established theoretical values for horizontal and vertical magnetic field intensities at the vehicle's location, the system achieves accurate calibration without needing complex local measurement infrastructure, thus improving accuracy while keeping data acquisition relatively simple.
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 simplifies the calibration process, enhances accuracy, and allows for calibration at a single position, reducing the complexity and increasing the precision of heading system measurements by accounting for hard iron errors.
Implementation Method 1
a magnetometer in such systems is calibrated using actual and theoretical readings at various magnetic headings of the vehicle
Data Source
AI summary
A method of calibrating a vehicle's heading system, such as the attitude heading and reference system of an aircraft or the heading system of a ship, positioned along the Earth's surface involves obtaining both actual and theoretical readings for the magnetometer of the heading system, and comparing these values to obtain calibration values for the heading system which are then averaged to obtain a universal average gain and offset for the magnetometer. The vehicle may be repositioned, such as to North, South, East, and west magnetic headings, with the procedure repeated at each of these headings, and the calibration values averaged, further increasing the accuracy.