Retro-reflector Tracking for Atmospheric Differential Absorption

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Solution Overview

Problem

Current methods for measuring atmospheric species remotely are limited in accuracy and flexibility, failing to effectively track differential absorptions over long paths and in dynamic environments.

Innovation Solution

A system utilizing a collocated source and detector with a retro-reflector on a vehicle, employing a long path differential absorption technique that transmits and receives laser beams of multiple wavelengths to measure atmospheric species concentrations, allowing for accurate tracking of species even when the retro-reflector is in motion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If current remote measurement methods are used, then measurement capability is provided, but measurement precision and accuracy are limited

Engineering Contradiction:

Improvemeasurement accuracyVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system segments the measurement function by separating the source and detector into different locations - the source is collocated with the retro-reflector on the moving platform, while the detector remains stationary. This segmentation allows the measurement path to be extended without increasing the complexity of the detection system at the remote location.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A retro-reflector is introduced as an intermediary element that enables the laser beam to be reflected back to the stationary detector. This intermediary allows the system to achieve long-path differential absorption measurements without requiring a complex moving detector system, thereby improving measurement precision while controlling device complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the retro-reflector is mounted on a moving vehicle, then flexibility and adaptability are improved, but measurement errors from platform motion increase

Engineering Contradiction:

Improvemeasurement flexibilityVSAvoidmeasurement accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system replaces complex mechanical tracking mechanisms with a passive retro-reflector mounted on the moving vehicle. The retro-reflector automatically returns the laser beam to the source regardless of the vehicle's motion, eliminating the need for active mechanical compensation systems and reducing measurement errors from platform motion.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The source and retro-reflector are collocated on the same moving platform, merging their functions. This combination allows the system to maintain adaptability for measuring atmospheric species along dynamic paths while the stationary detector eliminates errors from platform motion, achieving both flexibility and precision.

Inventive Principle:

Principle #5Merging (Combining)

3Length of stationary object

If a long path differential absorption technique is used, then measurement of atmospheric species over extended paths is enabled, but the system complexity increases

Engineering Contradiction:

Improveabsorption path lengthVSAvoidsystem complexity

Core Design Contradiction:

Length of stationary objectVSDevice complexity

Solution Approach 1:

Instead of moving the detector to follow the retro-reflector on the moving platform (which would increase complexity), the system inverts the approach by keeping the detector stationary and using the retro-reflector to return the beam. This inversion achieves long path lengths through the atmosphere without requiring a complex moving detection system.

Inventive Principle:

Principle #13The other way round (Inversion)

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 enables precise and flexible remote measurement of atmospheric species concentrations, reducing errors from atmospheric turbulence and platform motion, and allowing for real-time monitoring of species distributions over extended paths.

Implementation Method 1

a retro-reflector is mounted on a vehicle... transmitted to one or more retro-reflectors and reflected towards the detector as an incoming laser beam

Methodology Applied

Scientific EffectRetro-reflection: Retroreflector

Implementation Method 2

long path differential absorption technique... measuring concentrations of atmospheric species... tracking atmospheric differential absorptions

Methodology Applied

Scientific EffectDifferential absorption: Absorption (EM radiation)

Data Source

PatentUS8823938B2System, apparatus, and method for tracking atmospheric differential absorption

Publication Date: 2014.09.02 AEROSPACE CORP

AI summary

A system, apparatus, and method is provided to remotely measure atmospheric species using a long path differential absorption technique. In one embodiment, a source and a detector are collocated and at the far end of the absorption path a retro-reflector is mounted on a vehicle. The source generates an outgoing laser beam that is transmitted to the retro-reflector and reflected towards the detector as an incoming laser beam, and the detector receives the incoming laser beam that was reflected by the retro-reflector.