Multi-LIDAR Airflow Measurement for Aircraft Turbulence Detection

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Solution Overview

Problem

Current LIDAR systems face limitations in measuring airflow over a wide range and reducing aircraft shaking due to short measurement periods, mechanical scanning constraints, and limited laser output, which affects the detection and avoidance of air turbulence.

Innovation Solution

A multi-LIDAR system with multiple Doppler LIDAR devices emitting laser beams of identical wavelengths, allowing independent axis orientation for wider measurement areas and improved signal integration, enhancing redundancy and detection capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the measurement period is shortened to reduce aircraft shaking, then the shaking reduction effect increases, but the integration time of the reception signal becomes shorter and measurement precision deteriorates

Engineering Contradiction:
Improveshaking reduction effectVSAvoidmeasurement precision
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The patent divides the measurement function into multiple independent LIDAR devices, each capable of independent operation. This segmentation allows the system to perform multiple simultaneous measurements, effectively increasing the total integration time available for achieving precise measurements while maintaining short overall measurement periods for shaking reduction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent combines multiple LIDAR measurement results to achieve the final airflow vector. By merging data from multiple devices with different orientation directions, the system achieves both short measurement periods and high precision through signal combination and averaging.

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If a mechanism for scanning along the laser beam bearing is used, then two-dimensional vector measurement is enabled, but the measurement period is mechanically limited

Engineering Contradiction:
Improvetwo-dimensional vector measurement capabilityVSAvoidmeasurement period
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent segments the scanning function across multiple LIDAR devices, each with fixed independent orientation directions. Instead of one device mechanically scanning through all angles, multiple devices simultaneously cover different angular sectors, eliminating mechanical scanning limitations and reducing measurement period.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a single device performing sequential angular scanning (one-dimensional time-based approach) to multiple devices performing simultaneous multi-directional measurement (adding spatial dimension). This dimensional change allows two-dimensional vector measurement without mechanical scanning, significantly reducing measurement period.

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

3Length of stationary object

If the laser output is increased to expand the effective range, then the detection distance increases, but the current technical state of optical amplifiers limits the achievable range increase

Engineering Contradiction:
Improveeffective rangeVSAvoidreliability of optical amplifiers
Core Design Contradiction:
Length of stationary objectVSReliability

Solution Approach 1:

The patent combines the detection capabilities of multiple LIDAR devices to achieve extended effective range. By merging signals from multiple devices, the system achieves detection distances that would require prohibitively high laser output from a single device, thereby avoiding reliability issues with optical amplifiers.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses multiple copies of the LIDAR measurement system rather than attempting to enhance a single system. This copying approach allows the system to achieve extended range and improved reliability through redundancy and signal combination, avoiding the need for high-power optical amplifiers.

Inventive Principle:
Principle #26Copying

4Reliability

If a single LIDAR device is used, then the device complexity is low, but the redundancy with respect to defects is insufficient and the detectability is limited

Engineering Contradiction:
Improveredundancy with respect to defectsVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the LIDAR system into multiple independent devices, each performing the same measurement function. This segmentation provides redundancy against defects while maintaining relatively simple individual device designs, as each device can be a standardized module.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the system-level parameter of device quantity from one to multiple, thereby improving reliability through redundancy. The individual device parameters remain unchanged, allowing each device to maintain simple design while the system achieves enhanced reliability and detectability.

Inventive Principle:
Principle #35Parameter changes

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 multi-LIDAR system enables longer-range airflow measurement and quicker two-dimensional vector calculation, improving turbulence detection and reducing aircraft shaking through enhanced redundancy and detection efficiency.

Implementation Method 1

a wind velocity is measured by measuring a frequency variation (a wavelength variation) therein caused by the Doppler effect

Methodology Applied
Scientific EffectDoppler effect: Doppler Effect

Implementation Method 2

an emitted light beam is scattered by minute aerosols floating in the atmosphere, resulting scattered light is received by the Doppler LIDAR

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP2442136B1Multi-lidar system
Publication Date: 2020.06.03 JAPAN AEROSPACE EXPLORATION AGENCY
  • EP2442136B1 patent drawingFigure 1~2
  • EP2442136B1 patent drawingFigure 3~4
  • EP2442136B1 patent drawingFigure 5~6

AI summary

An object of the present invention is to provide a method enabling measurement in a wider range than a conventional LIDAR system and capable of measuring airflow information, which is used to reduce shaking of an airframe when an aircraft collides with turbulence, in a shorter period, and a device having corresponding functions. A multi-LIDAR system according to the present invention includes at least two optical remote airflow measurement devices of a Doppler LIDAR system employing laser light that are provided in a fixed relative position relationship, has functions for emitting lasers of identical wavelengths from the respective devices and receiving scattered light by the respective devices, thereby improving redundancy with respect to defects, and improves a detectability by increasing an integration amount of respective measurement signals.