Atmospheric parameter sensing system and atmospheric parameter resolving method

Abstract

The invention discloses an atmospheric parameter sensing system and an atmospheric parameter resolving method, and relates to the technical field of aircrafts, the system comprises a pressure value acquisition module, a vector flow velocity sensor and a resolving module; the pressure value acquisition module and the vector flow velocity sensor are both connected with the resolving module; the pressure value acquisition module is used for acquiring pressure data on the surface of the aircraft; the vector flow velocity sensor is used for collecting spanwise flow velocity components on the surface of the aircraft; the spanwise flow velocity component is the component of the airspeed in the spanwise direction of the wing; and the resolving module is used for resolving the actual attack angle, the actual sideslip angle and the actual air speed of the aircraft according to the pressure data and the spanwise flow velocity component. According to the application, the resolving workload is reduced.

Description

Technical Field

[0001] The present application relates to the field of aircraft technology, and in particular to an atmospheric parameter sensing system and an atmospheric parameter calculation method. Background Art

[0002] The atmospheric parameter sensing system is a system used to measure the airspeed, angle of attack and sideslip angle of an aircraft. At present, in the process of atmospheric parameter solution, there is a problem of coupling between sideslip angle and angle of attack, which makes the solution workload large. Summary of the invention

[0003] The purpose of this application is to provide an atmospheric parameter sensing system and an atmospheric parameter calculation method to reduce the calculation workload.

[0004] To achieve the above objectives, this application provides the following solutions:

[0005] In a first aspect, the present application provides an atmospheric parameter sensing system, the atmospheric parameter sensing system comprising: a pressure value acquisition module, a vector flow velocity sensor and a solution module; the pressure value acquisition module and the vector flow velocity sensor are both connected to the solution module;

[0006] The pressure value acquisition module is used to collect pressure data on the surface of the aircraft;

[0007] The vector flow velocity sensor is used to collect the spanwise flow velocity component of the aircraft surface; the spanwise flow velocity component is the component of the airspeed in the spanwise direction of the wing;

[0008] The calculation module is used to calculate the actual angle of attack, actual sideslip angle and actual airspeed of the aircraft according to the pressure data and the spanwise flow velocity component.

[0009] Optionally, the pressure value acquisition module includes a first differential pressure sensor, a second differential pressure sensor and a reference pressure measuring point, wherein the first differential pressure sensor is used to acquire a first differential pressure value between the first pressure measuring point and the reference pressure measuring point, and the second differential pressure sensor is used to acquire a second differential pressure value between the second pressure measuring point and the reference pressure measuring point;

[0010] The pressure data includes a first pressure difference value, the second pressure difference value and a third pressure difference value, the third pressure difference value is determined according to the first pressure difference value and the second pressure difference value, and the third pressure difference value is the pressure difference value between the first pressure measuring point and the second pressure measuring point.

[0011] Optionally, the solution module includes an angle of attack calculation unit; the angle of attack calculation unit is used to calculate an angle of attack calculation value according to an angle of attack calculation formula, and subtract an angle of attack correction amount from the angle of attack calculation value to obtain the actual angle of attack;

[0012] The attack angle calculation formula is expressed as:

[0013] in, α e is the calculated value of the angle of attack, A and B are both intermediate parameters, i is the first pressure measuring point, j is the second pressure measuring point, k is the reference pressure measuring point, Γ ki represents the first pressure difference value, Γ ij represents the third pressure difference value, Γ jk represents the second pressure difference value, a i , b i 、a j , b j 、a k and b k are all intermediate parameters, λ i and φ i are the position angle and circumferential angle of the first pressure measuring point, λ j and φ j are the position angle and circumferential angle of the second pressure measuring point, λ k and φ k are the position angle and circumferential angle of the reference pressure measuring point respectively.

[0014] Optionally, the solution module further includes a normal flow velocity component calculation unit; the normal flow velocity component calculation unit is used to:

[0015] Decomposing the actual airspeed into a normal flow velocity component and a spanwise flow velocity component, wherein the normal flow velocity component is a projection of the actual airspeed on the wing airfoil plane, and the spanwise flow velocity component is a projection of the actual airspeed on the wing leading edge;

[0016] Substituting the actual angle of attack, the sideslip angle of the normal flow velocity component and the test airspeed into the pressure distribution equation to obtain the shape-pressure coefficient;

[0017] Substituting the actual angle of attack, the sideslip angle of the normal flow velocity component and the shape pressure coefficient into the pressure distribution equation to obtain the normal flow velocity component;

[0018] The actual sideslip angle of the aircraft is calculated according to the normal flow velocity component and the spanwise flow velocity component.

[0019] Optionally, the actual angle of attack, the sideslip angle of the normal flow velocity component, and the test airspeed are substituted into a pressure distribution equation to obtain a shape pressure coefficient, specifically including:

[0020] According to the formula Calculating the shape-pressure coefficient;

[0021] Where ε is the pressure coefficient, ρ is the air density, V 0 represents the test airspeed, θj represents the airflow incident angle at the first pressure measuring point, θ i Represents the airflow incident angle of the second pressure measuring point.

[0022] Optionally, substituting the actual angle of attack, the sideslip angle of the normal flow velocity component and the shape pressure coefficient into a pressure distribution equation to obtain the normal flow velocity component specifically includes:

[0023] According to the formula calculating the normal flow velocity component;

[0024] Among them, V xy is the normal flow velocity component.

[0025] Optionally, it is characterized in that the actual sideslip angle of the aircraft is calculated according to the normal flow velocity component and the spanwise flow velocity component, specifically comprising:

[0026] According to the formula Calculating an actual sideslip angle of the aircraft;

[0027] Where β is the actual sideslip angle of the aircraft, V xy is the normal velocity component, V z is the spanwise flow velocity component.

[0028] Optionally, the solution module further includes an airspeed calculation unit, which calculates the actual airspeed according to the normal flow velocity component and the spanwise flow velocity component.

[0029] Optionally, calculating the actual airspeed according to the normal flow velocity component and the spanwise flow velocity component specifically includes:

[0030] According to the formula calculating the actual airspeed;

[0031] Among them, V ∞ is the actual airspeed, V xy is the normal velocity component, V z is the spanwise flow velocity component.

[0032] In a second aspect, the present application provides an atmospheric parameter solving method, the atmospheric parameter solving method applies the atmospheric parameter solving system, and the atmospheric parameter solving method includes:

[0033] Collect pressure data on the aircraft surface;

[0034] Collecting the spanwise flow velocity component of the aircraft surface; the spanwise flow velocity component is the component of the airspeed in the spanwise direction of the wing;

[0035] The actual angle of attack, actual sideslip angle and actual airspeed of the aircraft are calculated according to the pressure data and the spanwise flow velocity component.

[0036] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0037] The present application provides an atmospheric parameter sensing system and an atmospheric parameter solution method, wherein the pressure data of the aircraft surface is collected by a pressure value collection module, and the spanwise flow velocity component of the aircraft surface is collected by a vector flow velocity sensor, and the actual angle of attack, actual sideslip angle and actual airspeed of the aircraft are solved according to the spanwise flow velocity component and the pressure data. The atmospheric parameter theory based on the pressure and flow velocity fusion on the basis of the three-point method is implemented, and the spanwise flow velocity component is introduced to achieve the decoupling of the angle of attack and the sideslip angle, and the sideslip angle can be directly calculated without iterative calculation, thereby reducing the solution workload. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0039] Figure 1 A schematic diagram of the structure of an atmospheric parameter sensing system provided in one embodiment of the present application;

[0040] Figure 2 A theoretical schematic diagram of atmospheric parameters for pressure and velocity fusion provided in an embodiment of the present application;

[0041] Figure 3 A flowchart of an atmospheric parameter calculation method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0043] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0044] The three-point method is a representative algorithm of atmospheric parameter analysis methods. It is an atmospheric parameter analysis algorithm based on data from multiple pressure measuring points (generally 5 or 9). In order to establish an atmospheric parameter solution method that integrates pressure and velocity, research on the three-point method is essential. The general solution process of the three-point method is: based on the potential flow theory, the pressure distribution equation for each pressure measuring point on the surface is established; based on the pressure distribution equation for multiple pressure measuring points, the atmospheric parameters are solved; the calculated values ​​of the atmospheric parameters are compared with the true values, and the error correction caused by the upwash and sidewash effects of the wing are calibrated, including the angle of attack correction, the shape pressure coefficient, and the sideslip angle correction; the various corrections are summarized into a table, and the atmospheric parameters are corrected using the table lookup method.

[0045] However, the defects of the three-point method mainly include the following two points: (1) From the perspective of the algorithm, due to the existence of upwash and sidewash effects in the solution process, multiple correction coefficients are introduced: angle of attack correction δα, sideslip angle correction δβ, and pressure coefficient ε. These three coefficients are all related to airspeed, angle of attack, and sideslip angle. Therefore, the calibration of these three correction coefficients requires a lot of experiments, and finally forms a correction database under different airspeeds, angles of attack, and sideslip angles. In actual solution, it is necessary to determine the correction by looking up the table. However, due to the coupling of angle of attack and sideslip angle, the required correction cannot be directly obtained by looking up the table, and sometimes iterative calculation is required, which greatly increases the workload of solution. (2) From the perspective of the position of the pressure measuring point, according to the different positions of the pressure measuring points, the three-point method can be divided into the nose-based three-point method and the wing-based three-point method. Among them, the three-point method based on the nose will have a singularity when solving the sideslip angle, which brings difficulties to the solution of the sideslip angle and airspeed; the three-point method based on the wing can only accurately solve the angle of attack, but cannot solve the sideslip angle and airspeed, which greatly limits the application scenarios of the three-point method.

[0046] In recent years, non-analytical methods represented by various neural network algorithms have gradually emerged. However, neural network algorithms are complex to solve and require a large number of flight experiments to establish a sufficiently large training set. At the same time, in order to further improve the accuracy, neural network algorithms usually deploy a large number of distributed sensors on the hardware to improve the accuracy of the solution through a large number of distributed pressure or flow rate data points. Therefore, the hardware and software systems are very complex and are not suitable for atmospheric parameter solution.

[0047] The present application provides an atmospheric parameter sensing system, such as Figure 1 As shown, the atmospheric parameter sensing system includes: a pressure value acquisition module, a vector flow velocity sensor and a solution module; the pressure value acquisition module and the vector flow velocity sensor are both connected to the solution module.

[0048] The pressure value acquisition module is used to acquire pressure data on the surface of the aircraft.

[0049] The vector flow velocity sensor is used to collect the spanwise flow velocity component of the aircraft surface; the spanwise flow velocity component is the component of the airspeed in the spanwise direction of the wing.

[0050] The calculation module is used to calculate the actual angle of attack, actual sideslip angle and actual airspeed of the aircraft according to the pressure data and the spanwise flow velocity component.

[0051] The present application realizes the decoupling of the angle of attack and the sideslip angle by introducing the spanwise velocity component according to the atmospheric parameter theory of pressure-velocity fusion on the basis of the three-point method, and can directly calculate the actual sideslip angle without iterative calculation, thereby reducing the solution workload.

[0052] The pressure value acquisition module includes a first differential pressure sensor, a second differential pressure sensor and a reference pressure measuring point, the first differential pressure sensor is used to collect a first differential pressure value between the first pressure measuring point and the reference pressure measuring point, and the second differential pressure sensor is used to collect a second differential pressure value between the second pressure measuring point and the reference pressure measuring point.

[0053] The pressure data includes a first pressure difference value, the second pressure difference value and a third pressure difference value, the third pressure difference value is determined according to the first pressure difference value and the second pressure difference value, and the third pressure difference value is the pressure difference value between the first pressure measuring point and the second pressure measuring point.

[0054] In an exemplary embodiment, the aircraft is a drone. The vector flow rate sensor, the first differential pressure sensor, and the second differential pressure sensor are all disposed at a leading edge of a wing of the aircraft.

[0055] Based on the layout of a vector velocity sensor and two differential pressure sensors, the calculation of the aircraft's angle of attack, sideslip angle and airspeed is realized, such as Figure 2 As shown, the actual airspeed V to be calculated ∞ Decomposed into a normal velocity component Vxy and a spanwise velocity component Vz, wherein the normal velocity component is the projection of the actual airspeed on the wing airfoil plane, and the spanwise velocity component is the projection of the actual airspeed on the wing leading edge. For Vxy, it is equivalent to an angle of attack of α and a sideslip angle of 0°; for Vz, it is equivalent to an angle of attack of 0° and a sideslip angle of 90°. ∞ The true angle of attack is the angle of attack α of Vxy, and the true sideslip angle β has the following relationship with the velocity component:

[0056] According to the three-point method of the wing and the pressure distribution equation, if the pressure value at the first pressure measuring point i is P i , the pressure value at the second pressure measuring point j is P j , the pressure value at the reference pressure measuring point k is P k , then define Γ ij =P i-P j , Γ jk =P j -P k , Γ ki =P k -P i .

[0057] The solution module includes an angle of attack calculation unit; the angle of attack calculation unit is used to calculate an angle of attack calculation value according to an angle of attack calculation formula, and to subtract an angle of attack correction amount from the angle of attack calculation value to obtain the actual angle of attack. The angle of attack correction amount is obtained by data fitting.

[0058] The attack angle calculation formula is expressed as:

[0059] in, α e is the calculated value of the angle of attack, A and B are both intermediate parameters, i is the first pressure measuring point, j is the second pressure measuring point, k is the reference pressure measuring point, Γ ki represents the first pressure difference value, Γ ij represents the third pressure difference value, Γ jk represents the second pressure difference value, a i 、b i 、a j 、b j 、a k and b k are all intermediate parameters, λ i and φ i are the position angle and circumferential angle of the first pressure measuring point, λ j and φ j are the position angle and circumferential angle of the second pressure measuring point, λ k and φ k They are the position angle and circumference angle of the reference pressure measuring point. The position angle is the angle between the line from the corresponding pressure measuring point to the center of the ball and the axis of the machine head, and the circumference angle is 0° or 180°.

[0060] In an exemplary embodiment, according to different airspeed conditions and different sideslip angle conditions, a training group of multiple working conditions is obtained, and the fitting value of the angle of attack correction amount δα is calculated using the data of the training group. The angle of attack calculation value α e Subtracting the angle of attack correction δα from the airspeed condition of 10, 30, 50, 70 m / s and the sideslip angle condition of 0°, 5°, 10°, a total of 12 working conditions are used as the training group, and the fitting value of the angle of attack correction δα is calculated using the 12 sets of data in the training group.

[0061] For solving the normal flow velocity component Vxy, the three-point method can solve the angle of attack but cannot solve the sideslip angle, and the airspeed cannot be solved when the sideslip angle is unknown.

[0062] The solution module further includes a sideslip angle calculation unit; the sideslip angle calculation unit is used to:

[0063] 1) Substitute the actual angle of attack, the sideslip angle of the normal flow velocity component (known to be 0°) and the test airspeed into the pressure distribution equation to obtain the shape pressure coefficient.

[0064] 2) Substitute the actual angle of attack, the sideslip angle of the normal flow velocity component (known to be 0°) and the shape pressure coefficient into the pressure distribution equation to obtain the normal flow velocity component.

[0065] 3) Calculating the actual sideslip angle of the aircraft based on the normal flow velocity component and the spanwise flow velocity component.

[0066] Substituting the actual angle of attack, the sideslip angle of the normal flow velocity component (known to be 0°) and the actual airspeed into the pressure distribution equation, the shape pressure coefficient is obtained, which specifically includes:

[0067] According to the formula Calculating the shape-pressure coefficient;

[0068] Where ε is the pressure coefficient, ρ is the air density, V 0 represents the test airspeed, θ j represents the airflow incident angle at the first pressure measuring point, θ i Represents the airflow incident angle at the second pressure measuring point.

[0069] By fitting the shape-pressure coefficient to the estimated value of the angle of attack, a mapping relationship between the shape-pressure coefficient and the calculated value of the angle of attack can be obtained.

[0070] Substituting the actual angle of attack, the sideslip angle of the normal flow velocity component and the shape pressure coefficient into the pressure distribution equation to obtain the normal flow velocity component specifically includes:

[0071] According to the formula The normal flow velocity component is calculated.

[0072] Among them, V xy is the normal flow velocity component.

[0073] Calculating the actual sideslip angle of the aircraft according to the normal flow velocity component and the spanwise flow velocity component specifically includes:

[0074] According to the formula An actual sideslip angle of the aircraft is calculated.

[0075] Where β is the actual sideslip angle of the aircraft, Vxy is the normal velocity component, V z is the spanwise flow velocity component.

[0076] The solution module also includes an airspeed calculation unit, which calculates the actual airspeed according to the normal flow velocity component and the spanwise flow velocity component.

[0077] The actual airspeed is calculated based on the normal flow velocity component and the spanwise flow velocity component, specifically including: according to the formula Calculate the actual airspeed.

[0078] Among them, V ∞ is the actual airspeed, V xy is the normal velocity component, V z is the spanwise flow velocity component.

[0079] The present application proposes an atmospheric parameter theory of pressure-velocity fusion on the basis of the three-point method, and realizes the decoupling of the angle of attack and the sideslip angle by introducing the spanwise velocity component, thereby realizing the function of solving the sideslip angle and the airspeed at the leading edge of the wing, reducing the workload of calibration of the correction coefficient, and directly solving the equation to determine the corresponding correction value during the solution process, thereby simplifying the solution process of the analytical method and reducing the solution workload.

[0080] Based on the same inventive concept, the embodiment of the present application also provides an atmospheric parameter solution method for implementing the atmospheric parameter sensing system involved above. The implementation scheme for solving the problem provided by the method is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more atmospheric parameter solution method embodiments provided below can refer to the limitations on the atmospheric parameter sensing system above, and will not be repeated here.

[0081] In an exemplary embodiment, the present application provides an atmospheric parameter solution method, which uses the above-mentioned atmospheric parameter sensing system, such as Figure 3 As shown, a method for calculating atmospheric parameters includes the following steps.

[0082] Step 101: Collect pressure data on the surface of the aircraft.

[0083] Step 102: collecting the spanwise flow velocity component of the aircraft surface; the spanwise flow velocity component is the component of the airspeed in the spanwise direction of the wing.

[0084] Step 103: Calculate the actual angle of attack, actual sideslip angle and actual airspeed of the aircraft according to the pressure data and the spanwise flow velocity component.

[0085] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0086] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. An atmospheric parameter sensing system, characterized in that: The atmospheric parameter sensing system comprises: a pressure value acquisition module, a vector flow velocity sensor and a solution module; the pressure value acquisition module and the vector flow velocity sensor are both connected to the solution module; The pressure value acquisition module is used to collect pressure data on the surface of the aircraft; The vector flow velocity sensor is used to collect the spanwise flow velocity component of the aircraft surface; the spanwise flow velocity component is the component of the airspeed in the spanwise direction of the wing; The calculation module is used to calculate the actual angle of attack, actual sideslip angle and actual airspeed of the aircraft according to the pressure data and the spanwise flow velocity component.

2. The atmospheric parameter sensing system according to claim 1, characterized in that: The pressure value acquisition module includes a first differential pressure sensor, a second differential pressure sensor and a reference pressure measuring point, wherein the first differential pressure sensor is used to acquire a first differential pressure value between the first pressure measuring point and the reference pressure measuring point, and the second differential pressure sensor is used to acquire a second differential pressure value between the second pressure measuring point and the reference pressure measuring point; The pressure data includes a first pressure difference value, the second pressure difference value and a third pressure difference value, the third pressure difference value is determined according to the first pressure difference value and the second pressure difference value, and the third pressure difference value is the pressure difference value between the first pressure measuring point and the second pressure measuring point.

3. The atmospheric parameter sensing system according to claim 2, characterized in that: The solution module includes an angle of attack calculation unit; the angle of attack calculation unit is used to calculate an angle of attack calculation value according to an angle of attack calculation formula, and to obtain the actual angle of attack by subtracting an angle of attack correction amount from the angle of attack calculation value; The attack angle calculation formula is expressed as: in, α e is the calculated value of the angle of attack, A and B are both intermediate parameters, i is the first pressure measuring point, j is the second pressure measuring point, k is the reference pressure measuring point, Γ ki represents the first pressure difference value, Γ ij represents the third pressure difference value, Γ jk represents the second pressure difference value, a i , b i 、a j , b j 、a k and b k are all intermediate parameters, λ i and φ i are the position angle and circumferential angle of the first pressure measuring point, λ j and φ j are the position angle and circumferential angle of the second pressure measuring point, λ k and φ k are the position angle and circumferential angle of the reference pressure measuring point respectively.

4. The atmospheric parameter sensing system according to claim 3, characterized in that: The solution module further includes a normal flow velocity component calculation unit; the normal flow velocity component calculation unit is used to: Decomposing the actual airspeed into a normal flow velocity component and a spanwise flow velocity component, wherein the normal flow velocity component is a projection of the actual airspeed on the wing airfoil plane, and the spanwise flow velocity component is a projection of the actual airspeed on the wing leading edge; Substituting the actual angle of attack, the sideslip angle of the normal flow velocity component and the test airspeed into the pressure distribution equation to obtain the shape-pressure coefficient; Substituting the actual angle of attack, the sideslip angle of the normal flow velocity component and the shape pressure coefficient into the pressure distribution equation to obtain the normal flow velocity component; The actual sideslip angle of the aircraft is calculated according to the normal flow velocity component and the spanwise flow velocity component.

5. The atmospheric parameter sensing system according to claim 4, characterized in that: Substituting the actual angle of attack, the sideslip angle of the normal velocity component and the test airspeed into the pressure distribution equation, the shape pressure coefficient is obtained, which specifically includes: According to the formula Calculating the shape-pressure coefficient; Where ε is the pressure coefficient, ρ is the air density, V0 represents the test airspeed, θ j represents the airflow incident angle at the first pressure measuring point, θ i Represents the airflow incident angle of the second pressure measuring point.

6. The atmospheric parameter sensing system according to claim 5, characterized in that: Substituting the actual angle of attack, the sideslip angle of the normal flow velocity component and the shape pressure coefficient into the pressure distribution equation to obtain the normal flow velocity component specifically includes: According to the formula calculating the normal flow velocity component; Among them, V xy is the normal flow velocity component.

7. The atmospheric parameter sensing system according to claim 4, characterized in that Calculating the actual sideslip angle of the aircraft according to the normal flow velocity component and the spanwise flow velocity component specifically includes: According to the formula Calculating an actual sideslip angle of the aircraft; Where β is the actual sideslip angle of the aircraft, V xy is the normal velocity component, V z is the spanwise flow velocity component.

8. The atmospheric parameter sensing system according to claim 4, characterized in that: The solution module also includes an airspeed calculation unit, which calculates the actual airspeed according to the normal flow velocity component and the spanwise flow velocity component.

9. The atmospheric parameter sensing system according to claim 8, characterized in that: The actual airspeed is calculated according to the normal flow velocity component and the spanwise flow velocity component, specifically comprising: According to the formula calculating the actual airspeed; Among them, V ∞ is the actual airspeed, V xy is the normal velocity component, V z is the spanwise flow velocity component.

10. A method for calculating atmospheric parameters, characterized in that: The atmospheric parameter calculation method applies the atmospheric parameter calculation system according to any one of claims 1 to 9, and the atmospheric parameter calculation method comprises: Collect pressure data on the aircraft surface; Collecting the spanwise flow velocity component of the aircraft surface; the spanwise flow velocity component is the component of the airspeed in the spanwise direction of the wing; The actual angle of attack, actual sideslip angle and actual airspeed of the aircraft are calculated according to the pressure data and the spanwise flow velocity component.

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