Shock Front LiDAR Air Data Measurement
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Solution Overview
Problem
Traditional air data sensors for supersonic aircraft face issues such as calibration errors, foreign object damage, and bandwidth limitations, while optical Doppler velocimetry systems are costly and complex.
Innovation Solution
A shock front LiDAR system that uses light detection and ranging (LiDAR) to measure shock front distances and angles, allowing for the calculation of air data parameters like angle of attack, sideslip, and Mach number without the need for hyperspectral Doppler shift analysis, using relaxed laser and detector requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional air data sensors (pitot-static probes, angle of attack vanes) are used, then the system structure is simple and cost-effective, but the sensors are prone to foreign object damage, require calibration, and have bandwidth limitations
Solution Approach 1:
The patent replaces traditional mechanical air data sensors (pitot-static probes, angle of attack vanes) with an optical LiDAR-based sensing system. This substitution eliminates mechanical components that are susceptible to foreign object damage and calibration drift, while providing non-contact measurement capability. The optical system uses laser backscatter from shock fronts to derive air data parameters, fundamentally changing from mechanical to optical measurement principles.
Solution Approach 2:
The patent introduces shock front optical density variations as an intermediary medium for measurement. Instead of directly measuring air data parameters with physical sensors, the system measures the optical properties of shock fronts (which are themselves intermediaries created by supersonic flow). This indirect measurement approach through shock fronts provides durability while maintaining measurement accuracy.
2Measurement precision
If optical Doppler velocimetry systems are used, then measurement capability is improved, but the system becomes costly and complex due to high performance laser and sensor requirements
Solution Approach 1:
The patent changes the measurement parameter from Doppler velocity (requiring hyperspectral analysis) to optical density/attenuation of laser light. By measuring the attenuation of laser backscatter from shock fronts rather than Doppler shifts, the system achieves air data measurement capability with relaxed laser and detector specifications, eliminating the need for costly hyperspectral Doppler velocimetry equipment.
Solution Approach 2:
The patent employs a simplified optical detection approach that uses less expensive, more readily available laser and sensor components compared to high-performance Doppler velocimetry systems. The system trades the complexity and cost of precision Doppler measurement for a more robust, cost-effective optical attenuation measurement method that achieves sufficient measurement precision for air data applications.
3Reliability
If flush-mounted aircraft windows are used for remote sensing, then sensor protection is improved, but the system requires costly optical technology and loses direct air data contact
Solution Approach 1:
The patent replaces the need for physical air data sensors exposed to the external environment with an optical sensing system that measures shock front properties through the aircraft window. This substitution protects the sensors from foreign object damage while maintaining measurement capability, as the optical system can sense shock fronts remotely without direct contact with external airflow.
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
Provides a cost-effective and reliable method for determining air data parameters, reducing the complexity associated with traditional and optical Doppler systems, and enabling accurate flight control for supersonic aircraft.
Implementation Method 1
the backscatter of broadcast laser light is analyzed to infer air data parameters
Implementation Method 2
obtaining one or more data measurements from an interrogation region with at least one light detection and ranging (LiDAR) unit
Data Source
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AI summary
An air data method and system are disclosed. In one implementation, the method comprises obtaining one or more data measurements from an interrogation region with at least one light detection and ranging (LiDAR) unit along at least one line of sight. The data indicate the distance of a shock front of a supersonic aircraft from the LIDAR sensor, along its line of sight. The method further comprises sending the one or more data measurements to a processor operative to perform data processing. The data processing includes extracting one or more shock front distances from the one or more data measurements, and calculating one or more shock front angles from the one or more shock front distances. The data processing further includes calculating one or more air data parameters from the one or more shock front angles; these air data parameters may comprise the Mach angle, the angle of attack or the angle of sideslip.