Microscopic Imager for Aircraft Cloud Detection

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Solution Overview

Problem

Aircrafts face challenges in detecting and quantifying supercooled large water droplets (SLDs) in clouds due to their rapid ice accumulation, which can lead to engine issues and increased drag, as existing technologies struggle with accurate detection and interference fringes in images.

Innovation Solution

A microscopic imager system using a short pulse laser emitter, a fluorescent filter to increase spectral content, and optics to direct and receive reflected light, allowing for accurate imaging and classification of cloud particles, including SLDs, while maintaining short pulse duration to avoid interference fringes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a continuous laser beam is used for cloud particle detection, then the spectral content is sufficient for particle classification, but interference fringes appear in the images reducing measurement precision

Engineering Contradiction:
Improveparticle detection accuracyVSAvoidinterference fringes
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent applies periodic action by using pulsed laser illumination instead of continuous laser beam. The short pulse duration (nanosecond to microsecond range) creates periodic illumination that freezes the motion of cloud particles and eliminates the temporal coherence effects that cause interference fringes, while maintaining sufficient spectral content for particle classification through the broadband nature of the pulsed laser

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent changes the temporal parameter of the laser beam from continuous to pulsed, and adjusts the pulse duration to a specific range (nanosecond to microsecond). This parameter change reduces the coherence length of the light, thereby eliminating interference fringes while preserving the spectral characteristics needed for accurate particle detection and classification

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If a short pulse laser beam is used to avoid interference fringes, then measurement precision improves, but the spectral content is limited reducing particle classification accuracy

Engineering Contradiction:
Improveparticle detection accuracyVSAvoidspectral content
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent simultaneously optimizes multiple parameters of the pulsed laser system: pulse duration (temporal parameter) is set to nanosecond-microsecond range to eliminate fringes, while pulse energy and spectral bandwidth are adjusted to ensure sufficient spectral content remains for particle classification. The broadband nature of the pulsed laser maintains the spectral information needed for distinguishing different particle types

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If existing detection technologies are used for SLD detection, then the system complexity is low, but the detection accuracy and quantification capability are insufficient

Engineering Contradiction:
ImproveSLD detection accuracyVSAvoiddetection system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary imaging system that captures spatial distribution information of cloud particles. This imaging component acts as a mediator between the pulsed laser illumination and the detection system, providing visual confirmation and spatial context that enhances SLD detection accuracy without requiring complex additional sensors or processing systems

Inventive Principle:
Principle #24Intermediary (Mediator)

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 system effectively detects and classifies cloud particles, including SLDs, reducing interference fringes and enabling timely prevention of ice accumulation on aircraft surfaces, ensuring safe flight operations.

Implementation Method 1

The fluorescent filter is configured to convert the short pulse, limited band, laser beam into a short pulse, wide band, light beam such that the spectral content of the short pulse light beam is greater than the spectral content of the short pulse laser beam

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Implementation Method 2

The optics are configured to direct the short pulse, wide band, light beam to the cloud, receive a reflected portion of the short pulse light beam from the cloud

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3467538B1Microscopic imager for aircraft cloud condition detection
Publication Date: 2020.04.22 ROSEMOUNT AEROSPACE INC
  • EP3467538B1 patent drawingFigure 1
  • EP3467538B1 patent drawingFigure 2A
  • EP3467538B1 patent drawingFigure 2B

AI summary

An aircraft system is configured to detect conditions of a cloud (18). The aircraft system includes a laser emitter (20), a fluorescent filter (22), optics (30a-30d), and an imager (24). The laser emitter (20) generates a short pulse laser beam. The fluorescent filter (22) is configured to convert the short pulse laser beam into a short pulse light beam such that the spectral content of the short pulse light beam is greater than the spectral content of the short pulse laser beam. The optics (30a-30d) are configured to direct the short pulse light beam through a window (16) of the aircraft into the cloud (18). The imager (24) is configured to receive a reflected portion of the short pulse light beam from the cloud (18), and process the images to detect the cloud particles of interest.