Aircraft Magnetometer Vertical Magnetic Defect Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for determining the CAP of an aircraft using magnetic measurements are prone to errors due to vertical magnetic defects, which are not adequately identified or compensated for, especially when the aircraft's longitudinal inclination is not horizontal.
Innovation Solution
A process and device for compensating vertical magnetic defects in an aircraft's magnetometer, involving the acquisition of magnetic field vector values and attitude angles, calculation of magnetic CAP, recursive estimation of slope coefficients, and application of a vertical bias estimator to refine compensation coefficients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ground-based harmonization methods are used to compensate magnetic defects, then horizontal geometric harmonization values are obtained with good precision, but vertical magnetic faults cannot be identified or compensated for
Solution Approach 1:
The patent transitions from two-dimensional ground-based horizontal plane measurements to three-dimensional in-flight measurements by incorporating aircraft attitude angles (pitch, roll, yaw) and operating in non-horizontal flight conditions. This dimensional expansion enables the magnetometer to observe and compensate vertical magnetic faults that are geometrically observable only when moving away from the horizontal plane.
Solution Approach 2:
The patent changes the operational parameters from ground-based horizontal conditions to in-flight three-dimensional attitudes. By acquiring magnetic field measurements at various aircraft attitudes (pitch angles greater than 5 degrees, roll angles greater than 15 degrees), the system enables estimation of vertical magnetic defect compensation coefficients that were previously unobservable.
2Reliability
If complete 3-dimensional models of magnetic disturbances are used for compensation, then compensation values can be estimated, but the method is complex and sensitive to measurement noise
Solution Approach 1:
The patent segments the magnetic compensation problem into two distinct parts: horizontal geometric harmonization (handled by conventional ground-based methods) and vertical magnetic defect compensation (handled by the new in-flight estimation method). This segmentation allows each sub-problem to be solved with appropriately simplified models, reducing overall system complexity while maintaining accuracy.
Solution Approach 2:
The patent extracts the vertical magnetic defect compensation coefficients from the complete 3-dimensional compensation model. By isolating and estimating only the vertical bias coefficients during flight, the system avoids the complexity of full 3-D modeling while still achieving accurate vertical defect compensation.
3Reliability
If complete 3-dimensional models are used for compensation, then compensation values can be obtained, but specific prescribed maneuvers are required which are expensive and undesirable
Solution Approach 1:
The patent applies partial action by implementing only the necessary portion of the complete 3-D compensation model - specifically, the vertical magnetic defect compensation during flight. Rather than requiring full prescribed maneuvers for complete model estimation, the system performs a targeted estimation of vertical bias coefficients using simplified flight conditions, reducing operational burden while maintaining compensation accuracy.
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
The proposed solution enables precise compensation for vertical magnetic defects, improving the accuracy of CAP determination and ensuring the magnetometer's performance meets expected flight service standards without requiring complex three-dimensional models or specific maneuvers.
Implementation Method 1
an acquisition of a plurality of values of magnetic field vectors measured by the magnetometer in flight
Data Source
Figure 1
Figure 2
Figure 3
AI summary
This method includes a first step (41) of obtaining initial values of magnetic defect compensation coefficients of the magnetometer, and a second in-flight refinement step comprising: - a) an acquisition (42) of a plurality of values of magnetic field vectors and associated aircraft attitude angle values, - b) a calculation (50) of a magnetic heading as a function of the initial values of compensation coefficients and magnetic field vector values, - c) a recursive calculation (54) of a slope coefficient, as a function of a heading difference between the calculated magnetic heading and a reference magnetic heading, and aircraft attitude angle values, - d) a calculation (56) of a value of vertical magnetic defect compensation coefficient using a vertical bias estimator as a function of the slope coefficient, the aircraft attitude angle values and the local Earth magnetic field.