Inertial Reference Unit Installation Using Laser Measurement

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Solution Overview

Problem

Current methods for installing inertial reference units in aircraft are laborious, cumbersome, and difficult to achieve precise heading, roll, and pitch adjustments, leading to cumulative errors and reduced precision in attitude and heading data.

Innovation Solution

A method that determines and records support installation angles representing angular errors of the reference unit support relative to a theoretical aircraft coordinate system, allowing for imprecise initial installation and subsequent data correction, eliminating the need for complex tools and shims, and using a reference coordinate system defined by targets on the aircraft structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If mechanical adjustment methods with complex tool kits are used to achieve precise heading alignment, then positioning precision is improved, but device complexity and installation time increase significantly

Engineering Contradiction:

Improveheading alignment precisionVSAvoidtool kit complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical adjustment tools with a laser-based measurement system. Instead of using cumbersome mechanical tool kits for heading alignment, the invention uses laser interferometry to measure and determine the precise orientation of the reference unit support, thereby simplifying the installation process while maintaining high precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates a virtual model of the reference unit support by measuring the spatial coordinates of multiple points on the support structure using laser. This digital copy allows for precise calculation of installation angles without requiring physical adjustment tools, reducing complexity while preserving measurement accuracy.

Inventive Principle:

Principle #26Copying

2Manufacturing precision

If mechanical adjustment with multiple shims is used to achieve precise roll and pitch angles, then positioning precision is improved, but installation time and operational complexity increase

Engineering Contradiction:

Improveroll and pitch angle precisionVSAvoidinstallation time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent replaces the mechanical shim adjustment process with optical laser measurement. Instead of iteratively adding and removing shims to achieve correct roll and pitch angles, the invention directly measures the support's orientation using laser interferometry, calculating the installation angles mathematically, which dramatically reduces installation time while maintaining precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent performs preliminary measurement of the support installation angles during the installation process itself, rather than requiring subsequent adjustment. By measuring the coordinates of points on the support and calculating angles in real-time, the system eliminates the need for time-consuming iterative adjustments with shims after initial mounting.

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If cumulative errors from multiple junctions are accepted in traditional assembly, then ease of assembly is improved, but measurement precision deteriorates

Engineering Contradiction:

Improveassembly easeVSAvoidheading measurement precision

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent creates a precise digital representation of the reference unit support by measuring the three-dimensional coordinates of multiple points on its structure. This virtual model allows for accurate calculation of installation angles that compensate for assembly tolerances and junction errors, maintaining high measurement precision while allowing easier mechanical assembly.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent implements a feedback mechanism where the measured coordinates of points on the reference unit support are used to calculate actual installation angles, which then inform correction values stored in memory. This closed-loop approach compensates for cumulative assembly errors by mathematically determining the precise orientation of the support relative to the aircraft coordinate system.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS8733700B2Method for installing an inertial reference unit in an aircraft, and aircraft equipped in this way

Publication Date: 2014.05.27 AIRBUS OPERATIONS (SAS)

AI summary

The invention relates to a method for installing an inertial reference unit in an aircraft, in which: a reference unit support (1) is fixed to a structural element of the aircraft; support installation angles—in heading, roll and pitch—representative of angular errors of positioning of the reference unit support relative to an aircraft coordinate system are determined, this determination being based on the measurement of coordinates of points of a previously defined reference coordinate system and of characteristic points of the reference unit support; the said support installation angles are recorded in memory means, for the purposes of subsequent correction of data measured by the inertial reference unit. Preferably the reference coordinate system used is defined by means of targets formed on the structure of a segment of the aircraft for the purposes of joining this segment with an adjacent segment.