Magnetometer Calibration via Theoretical Field Comparison
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Solution Overview
Problem
Existing heading reference systems in vehicles, such as aircraft and ships, face challenges in accurately calibrating magnetometers due to hard iron disturbances and misalignments, requiring time-consuming and complex procedures that affect accuracy.
Innovation Solution
The method involves using theoretical magnetic field properties of the Earth, obtained from sources like websites, to calibrate magnetometers by comparing them with actual readings at multiple headings, allowing for efficient and accurate adjustment of magnetometer deviations and misalignments, thereby providing universal average gain and offset for improved measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If prior art calibration methods are used requiring numerous repositioning of vehicles for eight or more different positions, then calibration can be performed, but the calibration process becomes time-consuming and complex
Solution Approach 1:
The patent extracts and utilizes only the essential theoretical magnetic field properties (horizontal and vertical intensity) from the Earth's magnetic field model, comparing them directly with actual magnetometer readings at the vehicle's current position. This eliminates the need for numerous repositioning operations while maintaining calibration accuracy by focusing on the core magnetic field characteristics rather than requiring multiple positional measurements.
Solution Approach 2:
The patent introduces theoretical magnetic field properties as an intermediary reference standard. By comparing actual magnetometer readings against these pre-calculated theoretical values at the current vehicle position, the system achieves calibration without requiring multiple physical repositioning operations, thus reducing calibration time while maintaining precision.
2Measurement precision
If prior art calibration methods are used without theoretical magnetic field comparison, then calibration can be performed, but the complexity of the calibration procedure increases
Solution Approach 1:
The patent extracts and utilizes only the essential theoretical magnetic field properties (horizontal and vertical intensity) from the Earth's magnetic field model, comparing them directly with actual magnetometer readings at the vehicle's current position. This eliminates the need for numerous repositioning operations while maintaining calibration accuracy by focusing on the core magnetic field characteristics rather than requiring multiple positional measurements.
Solution Approach 2:
The patent introduces theoretical magnetic field properties as an intermediary reference standard. By comparing actual magnetometer readings against these pre-calculated theoretical values at the current vehicle position, the system achieves calibration without requiring multiple physical repositioning operations, thus reducing calibration time while maintaining precision.
3Ease of operation
If magnetometers are calibrated without accounting for hard iron disturbances and misalignment, then calibration is simpler, but measurement accuracy decreases
Solution Approach 1:
The patent employs a feedback mechanism where actual magnetometer readings are continuously compared against theoretical magnetic field properties at the vehicle's current position. This comparison provides feedback information that enables the system to detect and correct deviations caused by hard iron disturbances and misalignment, thereby maintaining measurement accuracy without requiring complex manual calibration procedures.
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 reliable heading information by accounting for hard iron disturbances and misalignments, reducing the need for multiple repositioning and increasing the efficiency of navigation systems.
Implementation Method 1
obtaining actual readings from the magnetometer at one or more headings for the vehicle
Data Source
AI summary
Systems and methods of calibrating and adjusting for deviations in 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 involve calibrating magnetometers for hard iron and misalignment errors using single heading measurements. This can be accomplished by 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. 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.