Angled Cloud Sensor Layout for Solar-Resistant Phase Detection

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Solution Overview

Problem

Existing optical sensors face challenges in detecting icing conditions from clouds while minimizing interference from ambient light, particularly requiring high-speed, sensitive electronics for short pulse width lasers.

Innovation Solution

The use of two independent detectors with complementary tilt angles and a quad detector photodiode masked by linear polarizers and opaque regions to avoid solar interference, allowing for cloud detection and phase discrimination without simultaneous solar interference, and enabling the use of lower-cost lasers and electronics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If short pulse width lasers are used to detect cloud reflection signals, then measurement precision for icing condition detection is improved, but high-speed, sensitive electronics are required which increases device complexity and cost

Engineering Contradiction:
Improvecloud detection precisionVSAvoidelectronics complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The detector is divided into multiple segments with different tilt angles, where each segment detects light from a specific angular range. This segmentation allows the system to use longer pulse width lasers without requiring high-speed electronics, as each segment processes a portion of the total signal independently, reducing the speed requirements for the electronics while maintaining detection precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces angular dimension by tilting detector segments at different angles relative to the laser beam path. This dimensional approach separates the detection of different spatial regions, allowing the use of lower-speed electronics since the angular separation provides spatial filtering that reduces the need for high temporal resolution in signal processing.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If ambient light filtering is increased to reduce solar interference, then measurement precision is improved, but the field of view and detection capability are restricted

Engineering Contradiction:
Improvesignal-to-noise ratioVSAvoiddetection coverage
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The detector is segmented into multiple sections with different tilt angles, where each segment is responsible for detecting light from a specific angular range. This segmentation allows the system to filter solar interference in certain angular directions while maintaining detection capability in other directions, thus preserving both signal-to-noise ratio and detection coverage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The multi-segment detector structure serves multiple functions simultaneously: it filters solar interference through angular selective detection, maintains broad detection coverage by covering multiple angular ranges, and enables cloud phase discrimination. This universal design achieves precision improvement without sacrificing adaptability.

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

3Reliability

If multiple angled detectors are used to avoid solar interference, then reliability of cloud detection is improved, but device complexity increases

Engineering Contradiction:
Improvecloud detection reliabilityVSAvoiddetector structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple detector segments with different tilt angles are combined into a single integrated detector assembly. This merging approach maintains the reliability benefits of multiple angled detection paths while reducing overall system complexity compared to using separate detector units, as the segments share common mounting, optics, and processing electronics.

Inventive Principle:
Principle #5Merging (Combining)

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 effectively detects clouds and discriminates cloud phases while reducing the need for high-speed electronics, using lower-cost components and avoiding solar interference, thus enhancing the reliability and efficiency of cloud detection systems.

Implementation Method 1

The first detector is oriented along a first detector path and has a first tilt angle and a first detector field of view. The first detector is configured to detect light reflected from an illumination volume and to generate a first detector signal that corresponds to a first intensity of detected light.

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

a quad detector photodiode masked by linear polarizers and opaque regions to avoid solar interference

Methodology Applied
Scientific EffectPolarization: Polarisation

Data Source

PatentEP4166997B1Multiple angled field-of-view cloud sensor
Publication Date: 2025.11.26 ROSEMOUNT AEROSPACE INC
  • EP4166997B1 patent drawingFigure 1
  • EP4166997B1 patent drawingFigure 2
  • EP4166997B1 patent drawingFigure 3

AI summary

An optical sensor (10) for an aircraft includes two detectors (14, 16), a light source (12), and a controller (100). The detectors (14, 16) are oriented along detector paths and have tilt angles and fields of view. The detectors (14, 16) are configured to detect light reflected from an illumination volume and to generate detector signals that correspond to intensities of detected light. The tilt angles are equal such that each detector (14, 16) is oriented in an opposite direction within a plane containing a light source path and the detector paths. The light source (12) is oriented along the light source path and is configured to illuminate the illumination volume which overlaps with the fields of view within a predetermined distance range. The controller (100) is configured to receive the detector signals, detect whether a cloud is present based upon the detector signals, determine a cloud phase, and calculate a density of the detected cloud.