Optical Icing Detector Using Polarized Light Sampling

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Solution Overview

Problem

Existing Optical Icing Conditions Detectors (OICD) require powerful computers and extensive computations to analyze complex light signals, resulting in voluminous and high-power-consuming system components, which are expensive and inefficient.

Innovation Solution

An OICD system using a reduced number of signal values, employing low-speed analog-to-digital converters and microprocessors, with a limited sampling of reflected light signals and three-channel detection, allowing for efficient calculation of cloud metrics using two-color illumination and specific polarization techniques.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If complex signal analyses of reflected light signals are performed to determine cloud metrics, then measurement precision of cloud metrics is improved, but device complexity and power consumption increase

Engineering Contradiction:
Improvecloud metrics measurement precisionVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the most essential signal characteristics (peak value and decay rate) from the reflected light signal, discarding redundant information. This selective extraction maintains measurement precision for cloud metrics while dramatically reducing computational complexity and system requirements

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of performing complete complex signal analysis, the patent applies partial action by analyzing only two specific parameters (peak and decay rate) of the reflected light signal. This partial analysis is sufficient to determine cloud metrics accurately without requiring full-spectrum complex computation

Inventive Principle:
Principle #16Partial or excessive action

2Measurement precision

If complex signal analyses are performed using powerful computers, then measurement precision is improved, but use of energy increases

Engineering Contradiction:
Improvecloud metrics measurement precisionVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent extracts only the essential features (peak and decay rate) from the reflected light signal, eliminating the need for powerful computers and extensive computations. This extraction approach maintains measurement precision while significantly reducing power consumption by using simple analog-to-digital converters and basic processing

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If extensive computations are performed to analyze light signals, then measurement precision is improved, but productivity decreases

Engineering Contradiction:
Improvecloud metrics measurement precisionVSAvoidsystem efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent extracts only the critical parameters (peak value and decay rate) from the reflected light signal, eliminating extensive computations. This approach maintains measurement precision while improving productivity by enabling faster, more efficient determination of cloud metrics with reduced computational burden

Inventive Principle:
Principle #2Taking out (Extraction)

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

This approach reduces system complexity and power consumption, enabling cost-effective and efficient determination of cloud metrics such as ice/liquid ratios and droplet size distributions, while maintaining accurate predictions of icing conditions on aircraft surfaces.

Implementation Method 1

measure a light signal reflected by the cloud formation

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

Each of the two analog channels includes a peak detector configured to generate a signal indicative of a peak of a light signal reflected by the cloud

Methodology Applied
Scientific EffectPhotoelectric detection: Photoelectric Effect

Implementation Method 3

Each of the two analog channels includes a post-peak slope detector configured to generate a signal indicative of a rate of decay of the light signal reflected by the cloud

Methodology Applied
Scientific EffectPhotoelectric detection: Photoelectric Effect

Data Source

PatentEP3222527B1Optically detecting cloud metrics using sampled analog measurements of light reflection
Publication Date: 2023.11.29 ROSEMOUNT AEROSPACE INC
  • EP3222527B1 patent drawingFigure 1
  • EP3222527B1 patent drawingFigure 2
  • EP3222527B1 patent drawingFigure 3

AI summary

Apparatus and associated methods relate to determining metrics of water particles in clouds by directing light pulses at a cloud and measuring a peak, a post-peak value and a high-frequency fluctuation of light signals reflected from the cloud. The light pulses include: a first pulse having circularly polarized light of a first wavelength; and a second pulse of a second wavelength. The reflected light signals include: a first reflected light signal having left-hand circular polarization of the first wavelength; a second reflected light signal having right-hand circular polarization of the first wavelength; and a third reflected light signal of the second wavelength. An extinction coefficient and a backscatter coefficient are determined based on the measured peak and post-peak slopes of the first and second reflected light signals. The measured high-frequency fluctuations of the three reflected light signals can be used to calculate cloud particle sizes.