Aerodynamic Angle Estimation Without Aircraft-Specific Calibration

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Solution Overview

Problem

Existing methods for estimating aerodynamic angles on aircraft, such as angle of attack and sideslip, require complex calibration and are prone to inaccuracies due to wind conditions and reliance on specific aircraft data, making them impractical for real-time applications and flight simulations.

Innovation Solution

A method utilizing inertial measurements and airspeed derivatives to calculate aerodynamic angles without requiring aircraft-specific calibration, using explicit mathematical relationships between airspeed derivatives and coordinate accelerations, applicable to any flying body.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional sensor-based systems (flow angle vanes, pressure sensors) are used to measure aerodynamic angles, then measurement precision is improved, but device complexity and maintenance requirements increase

Engineering Contradiction:
Improveaerodynamic angle measurement precisionVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent creates a virtual copy of the aerodynamic angle measurement function through computational estimation. Instead of directly measuring angles with physical sensors, the system computes equivalent angle information from inertial and airspeed data using mathematical models, thereby eliminating the need for complex physical angle sensors while maintaining measurement capability

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces mechanical sensor systems (flow angle vanes, pressure sensors) with a computational system based on inertial measurements and airspeed derivatives. The mechanical measurement approach is substituted with mathematical estimation using equations that relate inertial accelerations and airspeed changes to aerodynamic angles

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If aircraft-specific calibration data are used to improve estimation accuracy, then measurement precision is improved, but adaptability to different aircraft types deteriorates

Engineering Contradiction:
Improveaerodynamic angle estimation accuracyVSAvoidapplicability to different aircraft types
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent develops a universal estimation method based on fundamental aerodynamic relationships between inertial accelerations, airspeed derivatives, and aerodynamic angles. The approach uses general principles that apply to all flying bodies regardless of specific aircraft type, configuration, or mass distribution, making the system universally applicable without requiring aircraft-specific calibration

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent transforms the estimation approach from using aircraft-specific static calibration parameters to using dynamic measurements of inertial accelerations and airspeed derivatives. By changing from static calibration data to dynamic measured parameters, the system achieves both accuracy and universal applicability across different flight conditions and aircraft types

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If complex calibration procedures are implemented to improve precision, then measurement precision is improved, but ease of operation deteriorates

Engineering Contradiction:
Improveaerodynamic angle estimation accuracyVSAvoidcalibration requirement
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The system performs self-calibration through continuous measurement of inertial accelerations and airspeed derivatives during normal flight operations. The estimation algorithm automatically adapts to current flight conditions without requiring external calibration procedures, making the system easy to operate and maintain while preserving accuracy

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4088121B1Method and system for estimating aerodynamic angles of a flying body
Publication Date: 2025.08.27 SELT SRL
  • EP4088121B1 patent drawingFigure 1
  • EP4088121B1 patent drawingFigure 2
  • EP4088121B1 patent drawingFigure 3

AI summary

A computer implemented method for estimating angles of attack (α) and / or sideslip (β) of a flying body comprises the steps of: Providing data or measurements representative of the time derivative of the module of a speed of the flying body with respect to the air (V); Providing data or measurements representative of the corresponding projections of the coordinate acceleration (ax, ay, az) on the Cartesian reference frame fixed to the flying body (body axes); Calculating the angles of attack (α) and / or sideslip (β) on the basis of an mathematical relationship of the angles of attack and sideslip with the coordinate accelerations and said time derivative of the module of a speed of the body with respect to the air.