Airborne Sonic Anemometer for Icing-Resilient Air Data
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Solution Overview
Problem
Existing sonic anemometers are not designed for use on unmanned or manned aircraft due to their size, resilience against icing conditions, and acoustically noisy environments, limiting their ability to provide accurate air data measurements.
Innovation Solution
A sonic anemometer system with multiple emitters and receivers is mounted on an airborne platform, using continuous wave signals to measure air velocity and sound speed, enabling high update rates and resilience against acoustic noise and icing, allowing for accurate air data estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If commercial sonic anemometers are made small and light for UAV use, then they can be mounted on airborne platforms, but their performance is limited by acoustic noise from the UAV
Solution Approach 1:
The patent introduces a dedicated acoustic shield and isolation structure as an intermediary element between the sonic anemometer and the noisy UAV environment. This shield acts as a mediator that blocks external acoustic noise from reaching the sensitive microphones while allowing the acoustic signals from the emitters to pass through, thereby resolving the contradiction between lightweight design and noise immunity
Solution Approach 2:
The patent replaces traditional mechanical shielding methods with an acoustic field-based approach using carefully designed acoustic paths and signal processing. Instead of physically blocking all noise mechanically, the system uses acoustic field manipulation and digital signal processing to distinguish between useful acoustic signals and noise, achieving measurement precision without adding significant weight
2Reliability
If pitot tubes are used for airspeed measurement, then reliable air data can be obtained, but the system becomes vulnerable to ice blocking
Solution Approach 1:
The patent introduces sonic anemometers as an intermediary measurement system that does not rely on pitot tubes. The sonic anemometers measure airspeed through acoustic time-of-flight methods, providing a completely different measurement pathway that is immune to ice blocking. This intermediary system can detect when pitot tube data becomes invalid due to icing and provide backup measurements
Solution Approach 2:
The patent changes the measurement parameter from pressure-based (pitot tube) to acoustic-based (time-of-flight). By measuring the speed of sound and deriving airspeed from acoustic wave propagation characteristics rather than pressure differential, the system fundamentally changes how airspeed is measured, making it immune to ice blocking while maintaining reliability
3Adaptability or versatility
If sonic anemometers are designed for meteorological ground use, then they can measure weather data, but they are not resilient against icing or acoustic noise
Solution Approach 1:
The patent applies local quality by designing the sonic anemometer with specialized localized features for airborne operation. The microphones are positioned and shielded in specific locations to maximize noise rejection, the emitters are oriented to minimize acoustic interference, and the housing has localized thermal protection zones to prevent icing. These localized quality enhancements enable the device to operate reliably in harsh airborne environments while maintaining its core measurement capability
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 system provides robust air data measurements with high update rates, improving the accuracy of airspeed and temperature estimation in noisy and icing conditions, enhancing the reliability of aircraft flight data systems.
Implementation Method 1
at least one continuous wave piezo emitter operatively connected to receive a continuous wave output signal from the processing circuit and to emit the continuous wave output signal through the volume space
Implementation Method 2
at least one continuous wave piezo receiver spatially separated and operatively mounted to receive the continuous wave output signal emitted through the volume space from the at least one continuous wave piezo emitter
Implementation Method 3
determining via the at least one continuous wave processing circuit wind speed from a difference in phase between the emitted and received signals due to the time-of-flight between the spatial separation of the at least one continuous wave piezo emitter and the at least one continuous wave piezo receiver
Implementation Method 4
determining via the at least one continuous wave processing circuit wind speed from a difference in phase between the emitted and received signals
Data Source
AI summary
According the present invention, air velocity and speed of sound which can be used to estimate air temperature can be measured from a sonic anemometer system attached to an airborne platform. Using multiple sonic emitters and receivers coupled to an assembly attached to an airborne platform where the atmosphere is free to pass through the volume between the acoustic elements, air data products can be estimated from the acoustic transit time between acoustic emitters and receivers for use in an airborne data system. The measurement method has high update rates and is resilient against acoustic noise and icing conditions making it a robust sensing platform for use on aircraft.