Aircraft Airspeed Computation from Static Air Temperature Probes
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Solution Overview
Problem
Existing methods for calculating aircraft airspeed, such as pitot-static systems, optical sensors, and computational models, are prone to errors due to contaminants, model uncertainties, and high computational complexity, particularly in the high subsonic regime.
Innovation Solution
Utilizing static air temperature probes to measure static air temperature, combined with total air temperature probes, to calculate Mach number and airspeed through atmospheric physics equations, providing a simpler and more accurate method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pitot-static systems are used to calculate airspeed, then airspeed can be determined using pressure measurements, but the measurements are susceptible to errors from contaminants such as ice, volcanic ash, or insect nests obstructing the sensors
Solution Approach 1:
The patent replaces the mechanical pressure-based pitot-static system with a thermal-based airspeed determination system. Instead of using pressure sensors that are physically exposed and susceptible to contamination, the invention uses temperature probes (static and total air temperature sensors) to calculate airspeed through atmospheric physics equations. This substitution of measurement principle eliminates the contamination vulnerability inherent in exposed pressure sensors.
2Measurement precision
If computational models with numerous aircraft parameters are used to compute airspeed, then airspeed can be estimated, but the computations are computationally complex and iterative, relying on convergence which may not be guaranteed
Solution Approach 1:
The patent extracts and utilizes only the essential thermal parameters (static air temperature and total air temperature) needed for airspeed calculation, eliminating the need for complex iterative computational models that rely on multiple aircraft parameters such as angle of attack, lift, drag, weight, altitude, aerodynamic coefficients, and engine thrust. This extraction of core thermal measurement principles simplifies the computation while maintaining accuracy in the high subsonic regime.
3Measurement precision
If optical sensors (LIDAR) are used to compute airspeed, then velocity of remote particles can be measured, but expensive sensing devices and light sources are required, and the system is vulnerable to inaccuracies from volcanic ash and other particles
Solution Approach 1:
The patent replaces complex optical sensing systems (LIDAR) with simpler thermal sensing systems. Instead of using expensive optical sensors and light sources that are vulnerable to particle interference and require complex alignment and calibration, the invention uses temperature probes to measure static and total air temperatures. This substitution reduces device complexity and cost while eliminating vulnerability to particle-related measurement errors.
4Measurement precision
If Flush Air Data System (FADS) with flush-mounted static ports is used, then pressure distribution around the fuselage can be measured, but the sensors are susceptible to precipitation and contaminants when the airplane is not in service
Solution Approach 1:
The patent replaces the pressure-based FADS system with a temperature-based measurement system. Instead of using flush-mounted static ports that measure pressure distribution and are susceptible to precipitation and contaminants, the invention uses temperature probes to measure static and total air temperatures. This substitution eliminates the susceptibility to precipitation and contaminant accumulation while providing accurate airspeed data.
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 reduces reliance on pressure sensors susceptible to contamination, enhances accuracy, and simplifies calculations, offering a reliable airspeed computation even in high subsonic conditions.
Implementation Method 1
measure a static air temperature at an aircraft using a static air temperature probe
Implementation Method 2
measuring a total air temperature at the aircraft using a total air temperature probe
Implementation Method 3
calculating a Mach number associated with the aircraft at a current flight altitude based at least partially on the static air temperature
Implementation Method 4
calculating a true air speed of the aircraft based on the Mach number
Data Source
AI summary
A system may include a static air temperature probe attached to an aircraft, an electronic flight instrument system, and a processor. The processor may be configured to measure a static air temperature at the aircraft using the static air temperature probe. The processor may further be configured to calculate a Mach number associated with the aircraft based at least partially on the static air temperature. The processor may also be configured to calculate a true air speed of the aircraft based on the Mach number. The processor may display an indication of the true air speed using the electronic flight instrument system. The processor may also be configured to calculate the speed of sound based at least partially on the static air temperature.