Tunable Optical Filter Lidar System for Aircraft Sensing

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Solution Overview

Problem

Current laser-based sensor systems for aircraft face challenges in safely scanning wavelengths, particularly in the infrared and ultraviolet spectrum, due to limited selection of scanning laser systems and larger footprints, which complicates the measurement of parameters like speed, temperature, and air density.

Innovation Solution

Employing a tunable optical filter with a fixed laser that emits a laser beam with a center wavelength within a range of wavelengths, allowing the filter to scan through different wavelengths, thereby reducing safety issues and providing desired performance without the need for a tunable laser.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a tunable laser is used to scan through different wavelengths, then the measurement capability is improved, but the device complexity and safety issues increase

Engineering Contradiction:

Improvewavelength scanning capabilityVSAvoidlaser system complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent introduces a tunable optical filter as an intermediary component that scans through different wavelengths while the laser remains fixed. This filter acts as a mediator between the fixed laser and the detection system, enabling wavelength scanning without requiring a complex tunable laser. The filter selectively transmits different wavelengths to the detector, achieving spectral scanning capability while keeping the laser source simple and safe.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If infrared and ultraviolet lasers are used for wavelength scanning, then the measurement range is improved, but safety concerns and system footprint increase

Engineering Contradiction:

Improvewavelength range coverageVSAvoidlaser safety concerns

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

Instead of using different dangerous lasers (infrared, visible, ultraviolet) to scan wavelengths, the patent inverts the approach by using a single safe fixed-wavelength laser and scanning the wavelength selection through a tunable optical filter. This reverses the traditional methodology, achieving broad wavelength range coverage through filter scanning rather than laser tuning, thereby eliminating safety concerns associated with high-power infrared and ultraviolet lasers.

Inventive Principle:

Principle #13The other way round (Inversion)

3Device complexity

If a fixed laser with tunable optical filter is used, then system size and safety are improved, but the wavelength scanning capability must be maintained

Engineering Contradiction:

Improvesystem footprintVSAvoidwavelength scanning performance

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent replaces the mechanical/optical complexity of a tunable laser system with a fixed laser combined with a tunable optical filter. The filter scanning mechanism substitutes for the laser wavelength tuning mechanism, achieving the same functional result with a simpler, more compact, and safer system architecture. This substitution maintains full wavelength scanning capability while reducing system footprint and eliminating the need for complex laser tuning mechanisms.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 configuration enables safe and effective measurement of aircraft parameters using a wider selection of lasers, reducing safety concerns and system size while maintaining performance.

Implementation Method 1

The laser beam encounters aerosols in the air that reflect or 'backscatter' light towards the aircraft. Aerosols are fine solid particles, liquid particles, or both, suspended in air or other gases. The backscatter of the laser beam can also be caused by the molecules of air.

Methodology Applied

Scientific EffectBackscatter: Scattering

Implementation Method 2

The speed of the aircraft can be determined by comparing the frequency of the laser beam to the frequency in the backscatter. This shift in frequency is a Doppler effect that can be used to calculate the speed of the aircraft.

Methodology Applied

Scientific EffectDoppler effect: Doppler Effect

Implementation Method 3

The received backscatter light is filtered using a tunable optical filter system to form a filtered backscatter light. A control component derived from the laser radiation is filtered using the tunable optical filter system to form a filtered reference light.

Methodology Applied

Scientific EffectOptical filtering: Filter (optical)

Data Source

PatentUS20240264196A1Lidar sensor system with a tunable optical filter

Publication Date: 2024.08.08 THE BOEING CO

AI summary

A method, apparatus, system, and computer program product for sensing air. A projected component of a laser radiation is emitted as a set of laser beams into an atmosphere from an aircraft. A backscatter light generated in response to said emitting the set of laser beams into the atmosphere is received to form a received backscatter light. The received backscatter light is filtered using a tunable optical filter system to form a filtered backscatter light. A control component derived from the laser radiation is filtered using the tunable optical filter system to form a filtered reference light. A set of parameters is determined for the aircraft using the filtered backscatter light and the filtered reference light.