Aircraft Trajectory Correction Using Estimated Ground Speed

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Solution Overview

Problem

Aircraft guidance systems struggle to accurately align with a predetermined direction due to wind deviations, leading to trajectory overshoot and inefficiencies in air traffic control.

Innovation Solution

A method for calculating a roll command during the alignment phase using current angular deviation and estimated ground speed, which accounts for wind presence by combining air speed and stored wind speed vectors, allowing for autonomous guidance without relying on real-time satellite data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional guidance systems use only air speed and magnetic heading data, then the system complexity remains low, but trajectory accuracy deteriorates due to wind-induced deviations

Engineering Contradiction:
Improvetrajectory alignment accuracyVSAvoidguidance system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary computational process that calculates estimated ground speed by combining air speed data with stored wind speed information. This intermediary calculation serves as a mediator between the simple input data (air speed, heading) and the improved output (accurate trajectory alignment), achieving better measurement precision without directly increasing device complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system performs preliminary action by pre-storing wind speed information before the alignment phase begins. This preliminary data preparation allows the guidance system to compensate for wind effects during alignment without requiring complex real-time wind measurement equipment, thus improving trajectory accuracy while maintaining relatively simple system architecture

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If the guidance system relies on real-time satellite data for wind correction, then trajectory correction accuracy improves, but system reliability deteriorates when satellite data is unavailable

Engineering Contradiction:
Improvewind speed measurement accuracyVSAvoidsystem autonomy
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system performs preliminary action by pre-storing wind speed information obtained from satellite data before the alignment phase begins. This allows the system to operate autonomously during alignment using the pre-stored data, maintaining reliability even when real-time satellite data is unavailable, while still achieving improved trajectory correction accuracy

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates a copy of wind speed information by storing it in memory for later use during the alignment phase. This copied data serves as a reliable backup that maintains system autonomy, eliminating the dependency on real-time satellite data connection while preserving the ability to perform accurate wind compensation

Inventive Principle:
Principle #26Copying

3Measurement precision

If the aircraft reduces the angle of interception to compensate for wind, then trajectory accuracy improves, but the alignment time increases

Engineering Contradiction:
Improvealignment accuracyVSAvoidalignment phase duration
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces the mechanical/pilot-based compensation method (reducing angle of interception) with a computational approach. The guidance computer automatically calculates corrected roll commands based on estimated ground speed, achieving accurate alignment without requiring the aircraft to adopt suboptimal flight paths, thus maintaining both accuracy and efficiency

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

4Productivity

If the guidance system uses conventional piloting laws without wind compensation, then the ease of operation is maintained, but productivity deteriorates due to trajectory overshoot

Engineering Contradiction:
Improvealignment efficiencyVSAvoidguidance system operation
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The guidance system performs self-service by automatically calculating and applying wind compensation without requiring pilot intervention. The system autonomously computes estimated ground speed, determines angular deviation, and generates corrected roll commands, improving alignment efficiency while maintaining ease of operation as the pilot simply follows the automated guidance

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2597544B1Steering method for correcting the trajectory of an aircraft
Publication Date: 2016.05.11 THALES SA
  • EP2597544B1 patent drawingFigure 1
  • EP2597544B1 patent drawingFigure 2~3
  • EP2597544B1 patent drawingFigure 4~5

AI summary

The invention relates to a method for guiding an aircraft to correct a trajectory deviation due to wind, comprising a step of calculating a roll control input for the aircraft during a phase of aligning the aircraft's trajectory along a prescribed alignment direction passing through a determined point. The roll control calculation is performed based on a current angular difference between a straight line passing through the determined point and the aircraft, on the one hand, and the alignment direction, on the other hand, and a current estimated ground speed of the aircraft relative to a ground-fixed reference frame. The current estimated ground speed is calculated from a current airspeed of the aircraft relative to the surrounding air and a stored wind speed.The stored wind speed is obtained from at least one wind speed calculated from a first value equal to the aircraft's speed relative to a ground-based reference frame from a satellite navigation system, and a second value equal to the airspeed relative to the surrounding air. The first and second values ​​are taken simultaneously at least one time before or at the same time as the aircraft begins the alignment phase.