Climb Dive Marker Elevation Calculation for High Roll Angles
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Solution Overview
Problem
Existing aircraft instrument displays face challenges in accurately representing the climb-dive marker (CDM) at high roll angles, leading to divergent issues and invalid indicators due to the typical equation used for CDM elevation, especially during high rolls and winds.
Innovation Solution
A more accurate formula for CDM elevation is introduced, incorporating Angle of Attack (AoA) data, and a blended CDM value is calculated using a combination of the AoA and the original equation, with shifting ratios to maintain visibility of the CDM even at roll angles approaching +/- 90 degrees.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the typical equation for CDM elevation is used, then the CDM can be displayed at normal operating conditions, but the CDM becomes inaccurate or invalid at high roll angles approaching +/- 90 degrees
Solution Approach 1:
The patent changes the calculation parameters by introducing a new equation that incorporates roll angle (φ) as an additional variable. The new equation CDM el = atan2(Vzb, sqrt(Vxb^2 + Vyb^2)) - φ modifies the traditional elevation calculation to account for roll effects, allowing accurate CDM display across the full roll angle range including extreme conditions near +/- 90 degrees
2Device complexity
If the CDM is fixed horizontally in the display's field of view, then the display layout remains simple, but the CDM moves to the top or bottom edge and becomes invalid at high roll angles
Solution Approach 1:
The patent applies dynamics by making the CDM horizontal position variable rather than fixed. The CDM horizontal position is dynamically adjusted based on the aircraft roll angle, allowing the marker to remain within the valid display area even during extreme roll maneuvers, thus maintaining reliability without significantly increasing display complexity
Data Source
Figure 1A~1B
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AI summary
A method of calculating a climb-dive marker (CDM) that is visibly present on a display even as the aircraft approaches a roll angle of +/- 90° is provided. An exemplary CDM method comprises obtaining, an X-axis velocity, a Y-axis velocity, and a Z-axis velocity in aircraft body coordinates of an aircraft; calculating a CDM elevation; and displaying, by the controller, the calculated CDM elevation. The method can further comprise obtaining an angle of attack (AoA) of the aircraft and a roll angle of the aircraft, wherein the AoA is set as the value of the CDM elevation when the roll angle is within a preset range. The CDM elevation may also be calculated using a combination of the AOA and the CDM formula when roll angle is within a second preset range.