Doppler Shift Analysis Device Obstacle Peak Exclusion

Solution Overview

Problem

Conventional Coherent Doppler Lidar (CDL) systems face limitations in accurately estimating wind velocities at longer distances due to low signal-to-noise ratios and are restricted by laser output levels for safety reasons, leading to unreliable data and limited observation ranges.

Innovation Solution

A Doppler shift analysis device and method that includes a data acquisition unit for reflected light data and an operation unit with a peak-originating-from-obstacle exclusion unit, which analyzes the data to exclude peaks from obstacles, allowing for accurate Doppler shift analysis by using a peak-originating-from-obstacle exclusion process and fitting techniques to isolate aerosol-related peaks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If peak-searching method or moment method is used for Doppler shift analysis, then wind velocity can be estimated, but reliability of estimated values deteriorates considerably at far distance where SN ratio is low

Engineering Contradiction:

Improvewind velocity estimation accuracyVSAvoidreliability of estimated values

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent extracts and removes peak portions originating from obstacles (buildings, towers, etc.) from the reflected light spectrum before performing Doppler shift analysis. By separating obstacle-related peaks from aerosol-related peaks, the analysis focuses only on valid aerosol signals, thereby maintaining reliability even at far distances where signal-to-noise ratio is low.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the reflected light spectrum into multiple portions based on frequency characteristics, identifying and isolating peak portions that originate from obstacles versus those from aerosols. This segmentation allows selective analysis of only the relevant aerosol portions, improving measurement precision and reliability simultaneously.

Inventive Principle:

Principle #1Segmentation

2Length of stationary object

If laser output is increased to extend observation distance, then observation extent can be extended, but human body safety is compromised

Engineering Contradiction:

Improveobservation extentVSAvoidhuman body safety

Core Design Contradiction:

Length of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent converts the limitation of low laser output (which causes low signal-to-noise ratio) into an advantage by developing sophisticated signal processing methods that can extract valid Doppler shift information even from weak signals. The obstacle peak exclusion technique enables reliable analysis at extended distances without increasing laser power, thus maintaining safety while achieving longer observation extent.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Productivity

If obstacle peaks are included in Doppler shift analysis, then analysis can be performed with available data, but accuracy of wind velocity measurement is reduced

Engineering Contradiction:

Improvedata analysis efficiencyVSAvoidwind velocity measurement accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent extracts and removes peak portions originating from obstacles (buildings, towers, etc.) from the reflected light spectrum before performing Doppler shift analysis. By separating obstacle-related peaks from aerosol-related peaks, the analysis focuses only on valid aerosol signals, thereby maintaining reliability even at far distances where signal-to-noise ratio is low.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the reflected light spectrum into multiple portions based on frequency characteristics, identifying and isolating peak portions that originate from obstacles versus those from aerosols. This segmentation allows selective analysis of only the relevant aerosol portions, improving measurement precision and reliability simultaneously.

Inventive Principle:

Principle #1Segmentation

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

Enables accurate detection of Doppler shifts at longer distances, improving the reliability of wind velocity measurements and extending the observation range up to 30 km, while reducing the impact of obstacles and noise, and enhancing the accuracy of wind condition analysis.

Implementation Method 1

analyzing a Doppler shift of the reflected light data

Methodology Applied

Scientific EffectDoppler shift: Doppler Effect

Implementation Method 2

irradiating laser light into atmosphere to obtain scattering from atmospheric dust (aerosol)

Methodology Applied

Scientific EffectLight scattering: Scattering

Implementation Method 3

a laser light transmission unit for transmitting laser light

Methodology Applied

Scientific EffectLaser: Laser

Data Source

PatentUS10816668B2Doppler shift analysis device

Publication Date: 2020.10.27 METROWEATHER CO LTD

AI summary

Analysis device 3 is provided with a data acquisition unit 22 for acquiring reflected light data for a laser light reflected by an atmospheric aerosol, and a control unit 21 for analyzing a Doppler shift of the reflected light data. The control unit 21 is provided with a result smoothing unit 43 for excluding a peak portion 51 in the reflected light originating from an obstacle. Further, a peak portion 51 originating from an obstacle is determined to be a peak portion originating from an obstacle when there is a steep slope of a predetermined amount or more in reception intensity within a frequency of a predetermined extent from a transmission frequency of the laser light. The Doppler shift is thus analyzed with a high degree of accuracy.