Calibration method for airspeed system of trilateral flight unmanned aerial vehicle with fixed track angle

Abstract

The invention belongs to the field of unmanned aerial vehicle flight tests, and particularly relates to a calibration method for a trilateral flight unmanned aerial vehicle airspeed system with a fixed trajectory angle. Comprising the following steps: step 1, selecting a test point in an aircraft flight envelope; 2, the aircraft flies on three sides under the condition corresponding to the test point, and flight data of the first side, the second side and the third side in the stable level flight stage are obtained; 3, a plurality of flight data points of the first side, the second side and the third side are selected from the flight data, the course angle and the track angle of each flight data point are obtained, and according to the course angle and the track angle, whether the wind field unevenness in the flight process meets the requirement or not is judged; if so, entering step 4; if not, returning to the step 2, and re-executing the test point; 4, acquiring the ground speed of each flight data point, and calculating the wind speed according to the ground speed; 5, calculating the vacuum speed in the flight process according to the wind speed and the ground speed; and 6, calibrating the airspeed of the test point according to the vacuum speed.

Description

Technical Field

[0001] The present application belongs to the field of UAV flight test, and in particular to a method for calibrating an airspeed system of a trilateral flight UAV with a fixed trajectory angle. Background Art

[0002] The accuracy of airspeed system measurement has a very important impact on aircraft status monitoring, operation control, flight safety, etc. Most of the existing UAV systems are small and medium-sized aircraft, and airspeed calibration is generally performed through the aircraft's own GPS or DGPS, and common methods include round-trip flight method.

[0003] Since the GPS-based airspeed calibration method is sensitive to the wind field, in order to meet the requirement of uniform wind field in the flight area as much as possible, the flight airspace for airspeed calibration needs to be reduced as much as possible.

[0004] Therefore, it is desired to have a technical solution to overcome or at least alleviate at least one of the above-mentioned defects of the prior art. Summary of the invention

[0005] The purpose of this application is to provide a method for calibrating the airspeed system of a trilateral flight UAV with a fixed trajectory angle to solve at least one problem existing in the prior art.

[0006] The technical solution of this application is:

[0007] The first aspect of the present application provides a method for calibrating an airspeed system of a trilateral flight UAV with a fixed trajectory angle, comprising:

[0008] Step 1: Select a test point within the aircraft flight envelope;

[0009] Step 2: The aircraft performs three-leg flight at a fixed trajectory angle under the conditions corresponding to the test points to obtain flight data of the first leg, the second leg, and the third leg in the stable level flight stage;

[0010] Step 3: Select multiple flight data points of the first side, the second side, and the third side from the flight data, obtain the heading angle and the trajectory angle of each flight data point, and judge whether the wind field unevenness during the flight meets the requirements according to the heading angle and the trajectory angle;

[0011] If yes, proceed to step 4;

[0012] If not, return to step 2 and re-execute the test point;

[0013] Step 4: Obtain the ground speed of each flight data point, and calculate the wind speed based on the ground speed;

[0014] Step 5, calculating the true airspeed during the flight according to the wind speed and the ground speed;

[0015] Step 6: Perform test point airspeed calibration according to the true airspeed.

[0016] In at least one embodiment of the present application, a plurality of test points are selected within the flight envelope of the aircraft.

[0017] In at least one embodiment of the present application, the conditions corresponding to the test points include aircraft configuration, flight altitude, and flight speed.

[0018] In at least one embodiment of the present application, when the aircraft performs three-sided flight under the conditions corresponding to the test point, the first side maintains a first trajectory angle unchanged, the second side maintains a second trajectory angle unchanged, and the third side maintains a third trajectory angle unchanged.

[0019] In at least one embodiment of the present application, when the aircraft performs a three-sided flight under the conditions corresponding to the test point, the first trajectory angle and the second trajectory angle, and the second trajectory angle and the third trajectory angle differ by 90°.

[0020] In at least one embodiment of the present application, when the aircraft performs a three-sided flight under the conditions corresponding to the test point, the time of the stable level flight phase is 1 minute.

[0021] In at least one embodiment of the present application, in step three, obtaining the heading angle and the trajectory angle of each flight data point, and judging whether the wind field unevenness during the flight meets the requirements according to the heading angle and the trajectory angle, includes:

[0022] Get the first heading angle and the first trajectory angle of each flight data point on the first side, calculate the absolute value ψ1 of the difference between the first heading angle and the first trajectory angle corresponding to each flight data point, and calculate the average value of each absolute value ψ1

[0023] Obtain the second heading angle and the second trajectory angle of each flight data point on the second side, calculate the absolute value ψ2 of the difference between the second heading angle and the second trajectory angle corresponding to each flight data point, and calculate the average value of each absolute value ψ2

[0024] Obtain the third heading angle and the third trajectory angle of each flight data point on the third side, calculate the absolute value ψ3 of the difference between the third heading angle and the third trajectory angle corresponding to each flight data point, and calculate the average value of each absolute value ψ3

[0025] Determine whether both Tolerance represents a given decision threshold;

[0026] If so, the wind field unevenness during flight meets the requirements;

[0027] If not, the wind field unevenness during flight does not meet the requirements.

[0028] In at least one embodiment of the present application, in step 4, obtaining the ground speed of each flight data point and calculating the wind speed according to the ground speed include:

[0029] Get the eastward ground speed of each flight data point on the first side Northward

[0030] Get the eastward ground speed of each flight data point on the second side Northward

[0031] Get the eastward ground speed of each flight data point on the third side Northward

[0032] Based on eastward ground speed Northward Eastward ground speed Northward Eastward ground speed Northward Calculate wind speed:

[0033]

[0034]

[0035]

[0036]

[0037] in, is the easterly wind speed, is the north wind speed, and n is the number of flight data points.

[0038] In at least one embodiment of the present application, in step 5, calculating the true airspeed during the flight according to the wind speed and the ground speed includes:

[0039]

[0040]

[0041] Among them, V T is true air speed.

[0042] The second aspect of the present application provides a system for calibrating an airspeed system of a trilateral flight UAV with a fixed trajectory angle, comprising:

[0043] Test point selection module, used to select test points within the aircraft flight envelope;

[0044] A flight data acquisition module, used for the aircraft to perform three-leg flight at a fixed trajectory angle under the conditions corresponding to the test points, and to acquire flight data of the first leg, the second leg, and the third leg in a stable level flight stage;

[0045] a wind field unevenness determination module, for selecting a plurality of flight data points of the first side, the second side, and the third side from the flight data, respectively, obtaining a heading angle and a trajectory angle of each flight data point, and determining whether the wind field unevenness during the flight meets the requirements according to the heading angle and the trajectory angle;

[0046] If yes, then enter the wind speed calculation module;

[0047] If not, return to the flight data acquisition module and re-execute the test point;

[0048] A wind speed calculation module, used to obtain the ground speed of each flight data point and calculate the wind speed based on the ground speed;

[0049] A true airspeed calculation module, used to calculate the true airspeed during flight according to the wind speed and the ground speed;

[0050] The airspeed calibration module is used to perform test point airspeed calibration according to the true airspeed.

[0051] In at least one embodiment of the present application, a plurality of test points are selected within the flight envelope of the aircraft.

[0052] In at least one embodiment of the present application, the conditions corresponding to the test points include aircraft configuration, flight altitude, and flight speed.

[0053] In at least one embodiment of the present application, when the aircraft performs three-sided flight under the conditions corresponding to the test point, the first side maintains a first trajectory angle unchanged, the second side maintains a second trajectory angle unchanged, and the third side maintains a third trajectory angle unchanged.

[0054] In at least one embodiment of the present application, when the aircraft performs a three-sided flight under the conditions corresponding to the test point, the first trajectory angle and the second trajectory angle, and the second trajectory angle and the third trajectory angle differ by 90°.

[0055] In at least one embodiment of the present application, when the aircraft performs a three-sided flight under the conditions corresponding to the test point, the time of the stable level flight phase is 1 minute.

[0056] In at least one embodiment of the present application, in the wind field unevenness determination module, the heading angle and the trajectory angle of each flight data point are obtained, and according to the heading angle and the trajectory angle, whether the wind field unevenness during the flight meets the requirements is determined, including:

[0057] Get the first heading angle and the first trajectory angle of each flight data point on the first side, calculate the absolute value ψ1 of the difference between the first heading angle and the first trajectory angle corresponding to each flight data point, and calculate the average value of each absolute value ψ1

[0058] Obtain the second heading angle and the second trajectory angle of each flight data point on the second side, calculate the absolute value ψ2 of the difference between the second heading angle and the second trajectory angle corresponding to each flight data point, and calculate the average value of each absolute value ψ2

[0059] Obtain the third heading angle and the third trajectory angle of each flight data point on the third side, calculate the absolute value ψ3 of the difference between the third heading angle and the third trajectory angle corresponding to each flight data point, and calculate the average value of each absolute value ψ3

[0060] Determine whether both Tolerance represents a given decision threshold;

[0061] If so, the wind field unevenness during flight meets the requirements;

[0062] If not, the wind field unevenness during flight does not meet the requirements.

[0063] In at least one embodiment of the present application, in the wind speed calculation module, obtaining the ground speed of each flight data point and calculating the wind speed according to the ground speed include:

[0064] Get the eastward ground speed of each flight data point on the first side Northward

[0065] Get the eastward ground speed of each flight data point on the second side Northward

[0066] Get the eastward ground speed of each flight data point on the third side Northward

[0067] Based on eastward ground speed Northward Eastward ground speed Northward Eastward ground speed Northward Calculate wind speed:

[0068]

[0069]

[0070]

[0071]

[0072] in, is the easterly wind speed, is the north wind speed, and n is the number of flight data points.

[0073] In at least one embodiment of the present application, in step 5, calculating the true airspeed during the flight according to the wind speed and the ground speed includes:

[0074]

[0075]

[0076] Among them, V T is true air speed.

[0077] The invention has at least the following beneficial technical effects:

[0078] The present invention discloses a method for calibrating an airspeed system of a UAV with trilateral flight and fixed trajectory angle. The method adopts trilateral flight to operate the UAV so as to meet the requirement of a smaller flight airspace, and the required airspace is smaller. The method can calculate the true airspeed during the flight by analyzing the data of the stable level flight phase of the trilateral flight with the goal of minimizing the wind speed variance of the trilateral flight. The method can also reduce the influence of uneven wind fields, thereby calculating the true airspeed during the flight, completing the airspeed calibration and validity confirmation of the UAV, and improving the accuracy of the airspeed calibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] Figure 1 It is a schematic diagram of the relationship between true airspeed, ground speed and wind speed during a three-sided flight with a fixed trajectory angle according to an embodiment of the present application. DETAILED DESCRIPTION

[0080] In order to make the purpose, technical scheme and advantages of the implementation of this application clearer, the technical scheme in the embodiment of this application will be described in more detail below in conjunction with the drawings in the embodiment of this application. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described embodiments are part of the embodiments of this application, not all of them. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain this application, and should not be construed as limitations on this application. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The embodiments of this application are described in detail below in conjunction with the drawings.

[0081] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the scope of protection of the present application.

[0082] The following is combined with Figure 1 This application is described in further detail.

[0083] The first aspect of the present application provides a method for calibrating an airspeed system of a trilateral flight UAV with a fixed trajectory angle, comprising the following steps:

[0084] Step 1: Select a test point within the aircraft flight envelope;

[0085] Step 2: The aircraft performs three-side flight at a fixed trajectory angle under the conditions corresponding to the test points, and obtains flight data of the first side, the second side, and the third side in the stable level flight stage;

[0086] Step 3: Select multiple flight data points on the first side, the second side, and the third side from the flight data, obtain the heading angle and the trajectory angle of each flight data point, and judge whether the wind field unevenness during the flight meets the requirements according to the heading angle and the trajectory angle;

[0087] If yes, proceed to step 4;

[0088] If not, return to step 2 and re-execute the test point;

[0089] Step 4: Obtain the ground speed of each flight data point and calculate the wind speed based on the ground speed;

[0090] Step 5: Calculate the true airspeed during flight based on wind speed and ground speed;

[0091] Step 6. Calibrate the airspeed at the test point according to the true airspeed.

[0092] The present application discloses a method for calibrating the airspeed system of a trilateral flight drone with a fixed trajectory angle. In step one, multiple test points are selected within the flight envelope of the aircraft. The conditions corresponding to the test points include aircraft configuration, flight altitude, and flight speed. Test points under multiple different conditions are selected. In step two, the aircraft performs trilateral flight under the conditions of a given aircraft configuration, flight altitude, and flight speed corresponding to the test points. When the aircraft performs trilateral flight under the conditions corresponding to the test points, the first side maintains the first trajectory angle unchanged, the second side maintains the second trajectory angle unchanged, and the third side maintains the third trajectory angle unchanged. The first trajectory angle differs from the second trajectory angle, and the second trajectory angle differs from the third trajectory angle by 90°. The time of the stable level flight stage is 1 minute. The flight data of the first side, the second side, and the third side in the stable level flight stage under the conditions corresponding to the test points are recorded.

[0093] In a preferred embodiment of the present application, in step three, multiple flight data points of the first side, the second side, and the third side are respectively selected from the flight data, the flight data points recorded in the stable level flight stage of the first side, the second side, and the third side are basically the same, and n flight data points are respectively taken in the stable level flight stage of the first side, the second side, and the third side.

[0094] In this embodiment, according to the heading angle and trajectory angle of each flight data point, it is judged whether the wind field unevenness during the flight meets the requirements, as follows:

[0095] Get the first heading angle and the first trajectory angle of each flight data point on the first side, calculate the absolute value ψ1 of the difference between the first heading angle and the first trajectory angle corresponding to each flight data point, and calculate the average value of each absolute value ψ1

[0096] Obtain the second heading angle and the second trajectory angle of each flight data point on the second side, calculate the absolute value ψ2 of the difference between the second heading angle and the second trajectory angle corresponding to each flight data point, and calculate the average value of each absolute value ψ2

[0097] Obtain the third heading angle and the third trajectory angle of each flight data point on the third side, calculate the absolute value ψ3 of the difference between the third heading angle and the third trajectory angle corresponding to each flight data point, and calculate the average value of each absolute value ψ3

[0098] Determine whether both Tolerance represents a given decision threshold;

[0099] If so, the wind field unevenness during flight meets the requirements;

[0100] If not, the wind field unevenness during flight does not meet the requirements.

[0101] In the process of executing the test point, the data may be unavailable due to wind field problems. You only need to re-select a good weather to re-perform the flight test (i.e. return to step 2) and re-execute the test point.

[0102] The airspeed system calibration method of the trilateral flight drone with a fixed trajectory angle in this application is to calculate the wind speed when the wind field unevenness during the flight meets the test requirements. The speed during the round-trip flight is analyzed. If the wind speed is stable during the flight, the true airspeed (V T ), wind speed (V W ) and ground speed (V G ) meets the following conditions: Figure 1 The vector relationship shown in the figure is as follows: V represents speed, ψ represents the difference between the heading angle and the trajectory angle, 1 represents the first flight, 2 represents the second flight, and 3 represents the third flight. The mathematical expressions are shown in formula (1). The subscript T represents true airspeed, G represents ground speed, W represents wind speed, and j represents the jth flight side; the superscript E represents eastward speed and N represents northward speed.

[0103]

[0104] Since the true airspeed on each side is equal, the true airspeed in round-trip flight satisfies the relationship shown in equations (2) and (3):

[0105]

[0106]

[0107] Substituting equation (1) into equation (2) and equation (3), equation (4) and equation (5) are established:

[0108]

[0109]

[0110] Take n flight data points in the stable level flight stage of the first side, the second side, and the third side respectively. When the wind field is steady during the flight, take any data points in the flight of the two sides, and they all satisfy the relationship of equations (4) and (5). Solve equations (4) and (5), and the final wind speed expression is:

[0111]

[0112]

[0113]

[0114]

[0115] in, is the easterly wind speed, is the north wind speed, and n is the number of flight data points.

[0116] According to the above analysis, in step 4, the wind speed calculation process includes:

[0117] Get the eastward ground speed of each flight data point on the first side Northward

[0118] Get the eastward ground speed of each flight data point on the second side Northward

[0119] Get the eastward ground speed of each flight data point on the third side Northward

[0120] Based on eastward ground speed Northward Eastward ground speed Northward Eastward ground speed Northward Substitute into equations (6) and (7) to calculate the wind speed.

[0121] After obtaining the wind speed during the flight and combining it with the ground speed during the flight, the true airspeed during the flight can be obtained. Finally, the true airspeed during the three-sided flight is arithmetic averaged to obtain the accurate true airspeed and complete the calibration of the airspeed system.

[0122] In this embodiment, in step 5, according to the wind speed calculated in step 4, The true airspeed during the flight is calculated by taking the ground speed of the outbound and return trips during the stable level flight phase, and performing the arithmetic average of the true airspeed during the flight. The true airspeed under the given aircraft configuration, flight altitude and flight speed is finally obtained according to the calculation formula of formula (8).

[0123]

[0124]

[0125] Among them, V T is true air speed.

[0126] In step 6, after completing the airspeed calibration of the test point under the current aircraft configuration, flight altitude, and flight speed conditions, repeat steps 2 to 5 for the next test point in sequence until the airspeed calibration of all test points is completed.

[0127] The present invention discloses a method for calibrating an airspeed system of a trilateral flight drone with a fixed trajectory angle. Under the conditions of a given aircraft configuration, flight altitude, and flight speed, the aircraft completes a trilateral flight with a fixed trajectory angle. During the trilateral flight, the aircraft trajectory angles of each two adjacent sides differ by 90°. The flight data of the stable level flight stage of each side, such as the flight altitude, flight speed, aircraft heading angle, and aircraft trajectory angle, are recorded. Based on the flight data, it is determined whether the wind speed is stable. If the wind speed is stable, the average ground speed of each side is calculated, and the flight data is entered into the wind speed calculation formula to calculate the wind speed during the trilateral flight. The true true airspeed is calculated based on the wind speed to complete the airspeed calibration.

[0128] The airspeed system calibration method of a UAV in trilateral flight with a fixed trajectory angle of the present application calculates the true true airspeed with the goal of minimizing the wind speed variance of the trilateral flight. The calculated true true airspeed has better robustness, further reducing the influence of the wind field on the airspeed calibration; the requirements for the flight area are further relaxed, and the UAV airspeed system calibration under crosswind conditions can be achieved through a smaller flight area, thereby reducing the influence of the wind field on the calibration effect; the requirements for wind field unevenness are increased, and when the wind field unevenness does not meet the test requirements, re-testing is required; the method has universality and is suitable for airspeed calibration of different types of UAVs.

[0129] Based on the above-mentioned method for calibrating an airspeed system of a trilateral flight UAV with a fixed trajectory angle, a second aspect of the present application provides an airspeed system calibration system for a trilateral flight UAV with a fixed trajectory angle, comprising:

[0130] Test point selection module, used to select test points within the aircraft flight envelope;

[0131] The flight data acquisition module is used for the aircraft to perform three-leg flight at a fixed trajectory angle under the conditions corresponding to the test points, and obtain the flight data of the first leg, the second leg, and the third leg in the stable level flight stage;

[0132] The wind field unevenness determination module is used to select multiple flight data points of the first side, the second side, and the third side from the flight data, obtain the heading angle and the trajectory angle of each flight data point, and determine whether the wind field unevenness during the flight meets the requirements according to the heading angle and the trajectory angle;

[0133] If yes, then enter the wind speed calculation module;

[0134] If not, return to the flight data acquisition module and re-execute the test point;

[0135] Wind speed calculation module, used to obtain the ground speed of each flight data point and calculate the wind speed based on the ground speed;

[0136] True airspeed calculation module, used to calculate the true airspeed during flight based on wind speed and ground speed;

[0137] The airspeed calibration module is used to calibrate the airspeed at the test point according to the true airspeed.

[0138] The functions and specific implementation methods of the airspeed system calibration system of the trilateral flight UAV with a fixed trajectory angle of the present application, as well as the functions of each module, can be found in the above-mentioned airspeed system calibration method of the trilateral flight UAV with a fixed trajectory angle, which will not be repeated here.

[0139] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for calibrating the airspeed system of a trilateral flight drone with a fixed trajectory angle, characterized in that: include: Step 1: Select a test point within the aircraft flight envelope; Step 2: The aircraft performs three-leg flight at a fixed trajectory angle under the conditions corresponding to the test points to obtain flight data of the first leg, the second leg, and the third leg in the stable level flight stage; Step 3: Select multiple flight data points of the first side, the second side, and the third side from the flight data, obtain the heading angle and the trajectory angle of each flight data point, and judge whether the wind field unevenness during the flight meets the requirements according to the heading angle and the trajectory angle; If yes, proceed to step 4; If not, return to step 2 and re-execute the test point; Step 4: Obtain the ground speed of each flight data point, and calculate the wind speed based on the ground speed; Step 5, calculating the true airspeed during the flight according to the wind speed and the ground speed; Step 6: Perform test point airspeed calibration according to the true airspeed.

2. The method for calibrating the airspeed system of a trilateral flight drone with a fixed trajectory angle according to claim 1, characterized in that: A plurality of test points are selected within the flight envelope of the aircraft.

3. The method for calibrating the airspeed system of a trilateral flight drone with a fixed trajectory angle according to claim 2, characterized in that: The conditions corresponding to the test points include aircraft configuration, flight altitude, and flight speed.

4. The method for calibrating the airspeed system of a trilateral flight drone with a fixed trajectory angle according to claim 3, characterized in that: When the aircraft performs three-leg flight under the conditions corresponding to the test points, the first leg maintains the first trajectory angle unchanged, the second leg maintains the second trajectory angle unchanged, and the third leg maintains the third trajectory angle unchanged.

5. The method for calibrating the airspeed system of a trilateral flight drone with a fixed trajectory angle according to claim 4, characterized in that: When the aircraft performs three-sided flight under the conditions corresponding to the test points, the first trajectory angle and the second trajectory angle, and the second trajectory angle and the third trajectory angle differ by 90°.

6. The method for calibrating the airspeed system of a trilateral flight drone with a fixed trajectory angle according to claim 5, characterized in that: When the aircraft performs a three-way flight under the conditions corresponding to the test points, the time for the stable level flight phase is 1 minute.

7. The method for calibrating the airspeed system of a trilateral flight drone with a fixed trajectory angle according to claim 6, characterized in that: In step three, the heading angle and trajectory angle of each flight data point are obtained, and according to the heading angle and the trajectory angle, whether the wind field unevenness during the flight meets the requirements is judged, including: Get the first heading angle and the first trajectory angle of each flight data point on the first side, calculate the absolute value ψ1 of the difference between the first heading angle and the first trajectory angle corresponding to each flight data point, and calculate the average value of each absolute value ψ1 Obtain the second heading angle and the second trajectory angle of each flight data point on the second side, calculate the absolute value ψ2 of the difference between the second heading angle and the second trajectory angle corresponding to each flight data point, and calculate the average value of each absolute value ψ2 Obtain the third heading angle and the third trajectory angle of each flight data point on the third side, calculate the absolute value ψ3 of the difference between the third heading angle and the third trajectory angle corresponding to each flight data point, and calculate the average value of each absolute value ψ3 Determine whether both Tolerance represents a given decision threshold; If so, the wind field unevenness during flight meets the requirements; If not, the wind field unevenness during flight does not meet the requirements.

8. The method for calibrating the airspeed system of a trilateral flight drone with a fixed trajectory angle according to claim 7, characterized in that: In step 4, the ground speed of each flight data point is obtained, and the wind speed is calculated according to the ground speed, including: Get the eastward ground speed of each flight data point on the first side Northward Get the eastward ground speed of each flight data point on the second side Northward Get the eastward ground speed of each flight data point on the third side Northward Based on eastward ground speed Northward Eastward ground speed Northward Eastward ground speed Northward Calculate wind speed: in, is the easterly wind speed, is the north wind speed, and n is the number of flight data points.

9. The method for calibrating the airspeed system of a trilateral flight drone with a fixed trajectory angle according to claim 8, characterized in that: In step 5, the true airspeed during the flight is calculated according to the wind speed and the ground speed, including: Among them, V T is true air speed.

10. A three-sided flight UAV airspeed system calibration system with a fixed trajectory angle, characterized in that: include: Test point selection module, used to select test points within the aircraft flight envelope; A flight data acquisition module, used for the aircraft to perform three-leg flight at a fixed trajectory angle under the conditions corresponding to the test points, and to acquire flight data of the first leg, the second leg, and the third leg in a stable level flight stage; a wind field unevenness determination module, for selecting a plurality of flight data points of the first side, the second side, and the third side from the flight data, respectively, obtaining a heading angle and a trajectory angle of each flight data point, and determining whether the wind field unevenness during the flight meets the requirements according to the heading angle and the trajectory angle; If yes, then enter the wind speed calculation module; If not, return to the flight data acquisition module and re-execute the test point; A wind speed calculation module, used to obtain the ground speed of each flight data point and calculate the wind speed based on the ground speed; A true airspeed calculation module, used to calculate the true airspeed during flight according to the wind speed and the ground speed; The airspeed calibration module is used to perform test point airspeed calibration according to the true airspeed.

11. The airspeed system calibration system for trilateral flight of unmanned aerial vehicle with fixed trajectory angle according to claim 10, characterized in that: A plurality of test points are selected within the flight envelope of the aircraft.

12. The airspeed system calibration system for trilateral flight of unmanned aerial vehicle with fixed trajectory angle according to claim 11, characterized in that: The conditions corresponding to the test points include aircraft configuration, flight altitude, and flight speed.

13. The airspeed system calibration system for trilateral flight of unmanned aerial vehicle with fixed trajectory angle according to claim 12, characterized in that: When the aircraft performs three-leg flight under the conditions corresponding to the test points, the first leg maintains the first trajectory angle unchanged, the second leg maintains the second trajectory angle unchanged, and the third leg maintains the third trajectory angle unchanged.

14. The airspeed system calibration system for trilateral flight of unmanned aerial vehicle with fixed trajectory angle according to claim 13, characterized in that: When the aircraft performs three-sided flight under the conditions corresponding to the test points, the first trajectory angle and the second trajectory angle, and the second trajectory angle and the third trajectory angle differ by 90°.

15. The airspeed system calibration system for trilateral flight of unmanned aerial vehicle with fixed trajectory angle according to claim 14, characterized in that: When the aircraft performs a three-way flight under the conditions corresponding to the test points, the time for the stable level flight phase is 1 minute.

16. The airspeed system calibration system for trilateral flight of unmanned aerial vehicle with fixed trajectory angle according to claim 15, characterized in that: In the wind field unevenness determination module, the heading angle and trajectory angle of each flight data point are obtained, and according to the heading angle and the trajectory angle, whether the wind field unevenness during the flight meets the requirements is determined, including: Get the first heading angle and the first trajectory angle of each flight data point on the first side, calculate the absolute value ψ1 of the difference between the first heading angle and the first trajectory angle corresponding to each flight data point, and calculate the average value of each absolute value ψ1 Obtain the second heading angle and the second trajectory angle of each flight data point on the second side, calculate the absolute value ψ2 of the difference between the second heading angle and the second trajectory angle corresponding to each flight data point, and calculate the average value of each absolute value ψ2 Obtain the third heading angle and the third trajectory angle of each flight data point on the third side, calculate the absolute value ψ3 of the difference between the third heading angle and the third trajectory angle corresponding to each flight data point, and calculate the average value of each absolute value ψ3 Determine whether both Tolerance represents a given decision threshold; If so, the wind field unevenness during flight meets the requirements; If not, the wind field unevenness during flight does not meet the requirements.

17. The airspeed system calibration system for trilateral flight of unmanned aerial vehicle with fixed trajectory angle according to claim 16, characterized in that: In the wind speed calculation module, the ground speed of each flight data point is obtained, and the wind speed is calculated according to the ground speed, including: Get the eastward ground speed of each flight data point on the first side Northward Get the eastward ground speed of each flight data point on the second side Northward Get the eastward ground speed of each flight data point on the third side Northward Based on eastward ground speed Northward Eastward ground speed Northward Eastward ground speed Northward Calculate wind speed: in, is the easterly wind speed, is the north wind speed, and n is the number of flight data points.

18. The airspeed system calibration system for trilateral flight of unmanned aerial vehicle with fixed trajectory angle according to claim 17, characterized in that: In step 5, the true airspeed during the flight is calculated according to the wind speed and the ground speed, including: Among them, V T is true air speed.

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