Heading Reference System Calibration Using Theoretical Magnetic Field
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Solution Overview
Problem
Existing methods for calibrating heading reference systems on vehicles, such as aircraft and ships, are time-consuming and inaccurate due to reliance on multiple repositioning and lack of utilization of theoretical magnetic field properties, leading to errors from hard iron disturbances and misalignment.
Innovation Solution
A method that uses actual and theoretical magnetometer readings at various headings to calculate calibration values, incorporating Earth's magnetic field properties, allowing for efficient and accurate calibration of heading systems by subtracting hard iron offsets and misalignment corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple repositioning methods are used for calibration, then calibration accuracy is improved, but calibration time and complexity increase
Solution Approach 1:
The patent replaces the mechanical repositioning system with a computational approach. Instead of physically moving the vehicle to multiple positions, the system uses magnetometer readings taken at a single position and applies mathematical algorithms to calculate calibration values that compensate for hard iron disturbances and misalignment errors.
Solution Approach 2:
The patent introduces theoretical magnetic field properties as an intermediary between the magnetometer readings and the calibration values. By comparing actual readings with theoretically calculated values based on Earth's magnetic field properties, the system can determine calibration parameters without requiring multiple physical positions.
2Measurement precision
If multiple repositioning methods are used for calibration, then calibration accuracy is improved, but procedure complexity increases
Solution Approach 1:
The patent replaces the mechanical repositioning system with a computational approach. Instead of physically moving the vehicle to multiple positions, the system uses magnetometer readings taken at a single position and applies mathematical algorithms to calculate calibration values that compensate for hard iron disturbances and misalignment errors.
Solution Approach 2:
The system performs self-calibration by using its own magnetometer readings combined with theoretical magnetic field calculations. The calibration process is automated through computational algorithms that automatically determine calibration parameters without requiring external intervention or complex manual procedures.
3Measurement precision
If theoretical magnetic field properties are utilized, then calibration accuracy is improved, but data processing requirements increase
Solution Approach 1:
The patent performs preliminary calculations of the theoretical magnetic field properties before the calibration process. By pre-calculating what the magnetometer readings should be based on Earth's magnetic field properties and the vehicle's known orientation, the system simplifies the actual calibration computation to a comparison and adjustment process.
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 reduces the complexity of calibrating heading systems, ensuring reliable navigation by accounting for hard iron disturbances and misalignment errors.
Implementation Method 1
a magnetometer configured to measure strength of a local magnetic field along each of the three independent axes
Data Source
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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.