Laser Radar Adaptive Distance Resolution for Wind Speed
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Solution Overview
Problem
Laser radar devices face challenges in maintaining high distance resolution for accurate wind speed measurement, especially in varying atmospheric conditions, as the signal-to-noise ratio (SNR) changes with aerosol density, requiring adaptive distance resolution adjustments to follow environmental changes.
Innovation Solution
A laser radar device with an optical oscillator, modulator, antenna, receiver, and signal processor that dynamically adjusts distance resolution based on SNR by integrating spectra of adjacent range bins, maintaining a fixed time gate width and performing Fourier transforms to calculate wind speed and vector, while optimizing SNR through adaptive integration and resolution changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high distance resolution is set, then measurement accuracy is improved, but signal to noise ratio deteriorates in low aerosol density conditions
Solution Approach 1:
The patent implements dynamic switching between two distance resolution settings based on real-time atmospheric conditions. The system automatically selects high distance resolution when aerosol density is high (good atmospheric conditions) and switches to low distance resolution when aerosol density is low (bad atmospheric conditions), thereby adapting the measurement parameters to maintain optimal signal-to-noise ratio while preserving measurement capability.
Solution Approach 2:
The system changes the distance resolution parameter according to atmospheric conditions. By detecting aerosol density and adjusting the distance resolution setting accordingly, the system optimizes the balance between measurement precision and signal-to-noise ratio, ensuring reliable measurements across varying environmental conditions.
2Reliability
If distance resolution is changed in advance depending on measurement distance, then signal to noise ratio is improved at long distance, but adaptability to changing atmospheric environment deteriorates
Solution Approach 1:
The patent incorporates a feedback mechanism that continuously monitors atmospheric conditions (aerosol density) and automatically adjusts the distance resolution setting in real-time. This closed-loop control system detects changes in atmospheric environment and dynamically switches between high and low distance resolution modes, ensuring the system adapts to varying conditions rather than relying on pre-set configurations.
3Reliability
If distance resolution is set low, then signal to noise ratio is improved, but measurement accuracy of local changes deteriorates
Solution Approach 1:
The system dynamically adjusts distance resolution based on atmospheric conditions. When aerosol density is high, it uses high distance resolution to maintain measurement accuracy for detecting local changes such as wind gusts. When aerosol density is low, it switches to low distance resolution to maximize signal-to-noise ratio, thereby optimizing the balance between accuracy and reliability according to environmental conditions.
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 allows for high distance resolution in high SNR regions and low resolution in low SNR regions, improving measurement accuracy and adaptability to changing atmospheric conditions without degrading measurement accuracy.
Implementation Method 1
an optical oscillator oscillating laser light
Implementation Method 2
an optical modulator modulating the laser light oscillated by the optical oscillator
Implementation Method 3
receiving scattered light from a radiation target as received light
Implementation Method 4
an optical receiver performing heterodyne detection on the received light received by the optical antenna
Implementation Method 5
a fast Fourier transform processor calculating a spectrum of the received signal for each of the range bins, by performing Fourier transform on the received signal divided by the range bin divider at a fixed number of set sampling points
Data Source
AI summary
A laser radar device of the present invention includes: an optical oscillator oscillating laser light; an optical modulator modulating the laser light oscillated by the optical oscillator; an optical antenna radiating the laser light modulated by the optical modulator to an atmosphere, and receiving scattered light from a radiation target as received light; an optical receiver performing heterodyne detection on the received light received by the optical antenna; and a signal processor calculating for a range bin a spectrum of a received signal obtained by the heterodyne detection by the optical receiver, calculating a signal to noise ratio of the range bin, and integrating the spectrum of the range bin and spectra of one or more range bins adjacent to the range bin when the signal to noise ratio is less than or equal to a threshold value.