Aircraft Freestream Data Sensing with Ultrasonic Airflow Calibration
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Solution Overview
Problem
Conventional ultrasonic anemometers are limited to very low flows and thin boundary layers, making them unsuitable as primary air data sources throughout an aircraft's entire flight envelope, and existing systems fail to accurately derive freestream data.
Innovation Solution
Aircraft freestream data systems utilize a combination of ultrasonic air data systems (UADS) at diametrically opposed locations, integrated with static pressure sensors, and advanced processing techniques like neural networks to calibrate and derive freestream parameters, compensating for boundary layer and sideslip effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional ultrasonic anemometers are used to measure local flow data, then measurement can be achieved in very low flows and thin boundary layers, but the system cannot function as a primary air data source throughout the entire flight envelope
Solution Approach 1:
The system divides the measurement task into two segments: local flow measurement (performed by ultrasonic anemometers) and freestream data derivation (performed through calibration algorithms). This segmentation allows each component to operate within its optimal range while achieving the overall goal of reliable primary air data sourcing throughout the flight envelope.
Solution Approach 2:
The patent introduces calibration algorithms and computational processing as intermediaries between the local flow measurements and the desired freestream air data. These intermediaries transform limited local measurements into comprehensive flight envelope coverage through mathematical relationships and calibration procedures.
2Measurement precision
If ultrasonic anemometers extend into the flow path to measure local air data, then local flow measurement is achieved, but boundary layer effects and sideslip reduce measurement accuracy
Solution Approach 1:
The system uses feedback from multiple sensors (including static pressure sensors and multiple ultrasonic anemometers) to continuously monitor and correct for boundary layer effects and sideslip. The calibration algorithms process this feedback information to compensate for harmful factors and improve measurement precision.
Solution Approach 2:
The patent employs asymmetric sensor placement and differential measurement techniques to detect and compensate for sideslip effects. By measuring flow conditions at multiple locations and comparing the asymmetric differences, the system can calculate and correct for sideslip-induced measurement errors.
3Loss of information
If conventional ultrasonic anemometer systems are used, then local air data can be obtained, but accurate freestream data derivation and calibration are not achieved
Solution Approach 1:
The calibration algorithms serve multiple functions simultaneously: they derive freestream data from local measurements, correct for boundary layer effects, compensate for sideslip, and validate sensor performance. This multi-functionality reduces information loss without proportionally increasing device complexity.
Solution Approach 2:
The patent replaces complex mechanical calibration systems with computational algorithms. Instead of using additional mechanical sensors or complex physical calibration apparatus, the system uses neural networks and mathematical models to achieve accurate freestream data derivation, thereby reducing overall system complexity while maintaining accuracy.
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 determination of freestream data across the entire flight envelope, providing reliable air data for aircraft operations with enhanced accuracy and safety.
Implementation Method 1
by emitting an acoustic signal and determining a time-of-flight to various acoustic sensors
Implementation Method 2
Ultrasonic anemometers (e.g., ultrasonic air data systems (UADS)) can be used to derive local flow data
Data Source
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AI summary
An aircraft freestream data system can include a first ultrasonic air data system (UADS) (101) configured to sense local acoustic properties at a first location on an aircraft, a first local air data module (103) operatively connected to the first UADS and configured to determine first local air data of the first location and to output first local air data, and a freestream data module (105) operatively connected to the first local air data module. The freestream data module can be configured to receive the first local air data from the local air data module, determine one or more freestream air data parameters based on at least the first local air data, and output the one or more freestream air data parameters to one or more aircraft consuming systems.