Optical Air Data System Using Molecular Scattering
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Solution Overview
Problem
Existing Optical Air Data Systems (OADS) face challenges in reliably measuring air speed, air temperature, and air pressure due to unpredictable aerosol distributions and scarcity of aerosols at varying altitudes, which limits their accuracy and ability to detect wind shear and other hazardous wind conditions crucial for aircraft safety and wind power system management.
Innovation Solution
A method and system utilizing multiple transceivers to project and receive laser radiation, distinguishing molecular and aerosol scattered components to determine air temperatures, wind speeds, and directions, with a tunable laser and optical notch filters to calculate Doppler shift and air parameters, enabling accurate measurements even in aerosol-scarce regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If prior art OADS rely on scattered light from aerosols, then air speed can be measured, but the measurements become unpredictable due to varying aerosol distributions with altitude and cloud content
Solution Approach 1:
The patent introduces molecular scattering as an intermediary mechanism to replace aerosol scattering. By measuring Rayleigh scattering from air molecules instead of Mie scattering from aerosols, the system eliminates the unpredictability caused by varying aerosol distributions while maintaining the ability to measure air speed through Doppler shift detection
Solution Approach 2:
The patent changes the measurement parameter from aerosol-based scattering to molecular-based scattering. This parameter change allows the system to operate reliably across all altitudes and weather conditions, as molecular scattering is consistent and predictable unlike aerosol scattering which varies with cloud content and altitude
2Adaptability or versatility
If OADS operate in regions with few aerosols, then the system can function in more atmospheric regions, but reliable air data measurements cannot be determined
Solution Approach 1:
The patent replaces aerosols as the scattering intermediary with air molecules. This substitution enables the system to operate reliably in aerosol-scarce regions (such as clear skies and high altitudes) because molecular scattering is present throughout the atmosphere regardless of aerosol content
Solution Approach 2:
The patent segments the scattering contribution into molecular scattering (Rayleigh) and aerosol scattering (Mie) components, then selectively uses the molecular scattering component for measurements. This segmentation allows the system to obtain reliable data in regions where aerosols are absent or variable
3Measurement precision
If prior art OADS use aerosol scattered light, then air speed can be determined, but air temperature and air pressure cannot be determined
Solution Approach 1:
The patent makes the laser radar system multi-functional by using molecular scattering to measure not only air speed through Doppler shift but also air temperature and air pressure through the characteristics of Rayleigh scattering. This universal approach allows a single system to provide comprehensive atmospheric data that was previously impossible with aerosol-based systems
Solution Approach 2:
The patent uses air molecules as the universal intermediary that provides information about multiple atmospheric parameters. Molecular scattering characteristics contain embedded information about temperature, pressure, and velocity, allowing the system to extract multiple parameters from a single measurement process
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 provides reliable and accurate remote sensing of air parameters, enhancing aircraft safety, wind power system control, and weather monitoring by overcoming limitations of previous systems, particularly in detecting wind shear and microbursts.
Implementation Method 1
distinguish molecular scattered laser radiation from aerosol scattered laser radiation
Implementation Method 2
aerosol scattered laser radiation
Implementation Method 3
The OADS may also measure the Doppler effect by receiving backscattered light and measuring its return frequency to determine speed
Implementation Method 4
The wavelength of the tunable laser is swept and the control signal and backscatter signal are compared to determine Doppler shift
Data Source
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AI summary
Systems and methods for sensing air includes at least one, and in some embodiments three, transceivers for projecting the laser energy as laser radiation to the air. The transceivers are scanned or aligned along several different axes. Each transceiver receives laser energy as it is backscattered from the air. A computer processes signals from the transceivers to distinguish molecular scattered laser radiation from aerosol scattered laser radiation and determines air temperatures, wind speeds, and wind directions based on the scattered laser radiation. Applications of the system to wind power site evaluation, wind turbine control, traffic safety, general meteorological monitoring and airport safety are presented.