Calibration method for airspeed system of round-trip flight unmanned aerial vehicle with fixed course angle

Abstract

The invention belongs to the field of flight tests of unmanned aerial vehicles, and particularly relates to a calibration method for an airspeed system of a round-trip flight unmanned aerial vehicle with a fixed course angle. Comprising the following steps: step 1, selecting a test point in an aircraft flight envelope; step 2, the aircraft flies back and forth under the condition corresponding to the test point, and flight data of the going path and the returning path in the stable level flight stage are obtained; step 3, respectively selecting a plurality of flight data points of a going path and a returning path from the flight data, acquiring a course angle and a track angle of each flight data point, and according to the course angle and the track angle, judging whether the non-uniformity of the wind field in the flight process meets the requirement; 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 air speed of the test point according to the vacuum speed.

Description

Technical Field

[0001] The present application belongs to the field of unmanned aerial vehicle flight testing, and in particular relates to a method for calibrating an airspeed system of a round-trip unmanned aerial vehicle with a fixed heading 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, it is difficult to maintain a stable wind speed in the atmospheric wind field in real experiments. The airspeed calibration method in existing public literature does not consider the impact of uneven wind speed.

[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 round-trip UAV with a fixed heading angle, so as to solve at least one problem existing in the prior art.

[0006] The technical solution of this application is:

[0007] A second aspect of the present application provides a method for calibrating an airspeed system of a round-trip UAV with a fixed heading angle, comprising:

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

[0009] Step 2: The aircraft performs a round trip flight at a fixed heading angle under the conditions corresponding to the test points, and obtains flight data of the outbound and return trips in the stable level flight stage;

[0010] Step 3: Select multiple flight data points of the outbound trip and the return trip 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 a round trip flight under the conditions corresponding to the test point, the first heading angle is maintained unchanged on the outbound journey, and the second heading angle is maintained unchanged on the return journey.

[0019] In at least one embodiment of the present application, when the aircraft performs a round trip flight under the conditions corresponding to the test point, a first heading angle of the outbound trip differs from a second heading angle of the return trip by 180°.

[0020] In at least one embodiment of the present application, when the aircraft performs a round trip 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] Obtain the first heading angle and the first trajectory angle of each flight data point on the outbound journey, 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 return trip, 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] Determine whether it is satisfied Tolerance represents a given decision threshold;

[0025] If so, the wind field unevenness during flight meets the requirements;

[0026] If not, the wind field unevenness during flight does not meet the requirements.

[0027] 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:

[0028] Get the eastbound ground speed of each flight data point on the outbound trip Northward

[0029] Get the eastward ground speed of each flight data point on the return trip Northward

[0030] Based on eastward ground speed Northward Eastward ground speed Northward Calculate wind speed:

[0031]

[0032] in, is the easterly wind speed, is the north wind speed, and n is the number of flight data points.

[0033] 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:

[0034]

[0035] Among them, V T is true air speed.

[0036] A second aspect of the present application provides an airspeed system calibration system for a round-trip UAV with a fixed heading angle, comprising:

[0037] Test point selection module, used to select test points within the aircraft flight envelope;

[0038] A flight data acquisition module, used for the aircraft to perform a round trip flight at a fixed heading angle under the conditions corresponding to the test points, and to acquire flight data of the outbound and return trips in the stable level flight stage;

[0039] A wind field unevenness determination module is used to select a plurality of flight data points of the outbound trip and the return trip 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;

[0040] If yes, then enter the wind speed calculation module;

[0041] If not, return to the flight data acquisition module and re-execute the test point;

[0042] 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;

[0043] A true airspeed calculation module, used to calculate the true airspeed during flight according to the wind speed and the ground speed;

[0044] The airspeed calibration module is used to perform test point airspeed calibration according to the true airspeed.

[0045] In at least one embodiment of the present application, a plurality of test points are selected within the flight envelope of the aircraft.

[0046] In at least one embodiment of the present application, the conditions corresponding to the test points include aircraft configuration, flight altitude, and flight speed.

[0047] In at least one embodiment of the present application, when the aircraft performs a round trip flight under the conditions corresponding to the test point, the first heading angle is maintained unchanged on the outbound journey, and the second heading angle is maintained unchanged on the return journey.

[0048] In at least one embodiment of the present application, when the aircraft performs a round trip flight under the conditions corresponding to the test point, a first heading angle of the outbound trip differs from a second heading angle of the return trip by 180°.

[0049] In at least one embodiment of the present application, when the aircraft performs a round trip flight under the conditions corresponding to the test point, the time of the stable level flight phase is 1 minute.

[0050] 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:

[0051] Obtain the first heading angle and the first trajectory angle of each flight data point on the outbound journey, 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

[0052] Obtain the second heading angle and the second trajectory angle of each flight data point on the return trip, 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

[0053] Determine whether it is satisfied Tolerance represents a given decision threshold;

[0054] If so, the wind field unevenness during flight meets the requirements;

[0055] If not, the wind field unevenness during flight does not meet the requirements.

[0056] 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:

[0057] Get the eastbound ground speed of each flight data point on the outbound trip Northward

[0058] Get the eastward ground speed of each flight data point on the return trip Northward

[0059] Based on eastward ground speed Northward Eastward ground speed Northward Calculate wind speed:

[0060]

[0061] in, is the easterly wind speed, is the north wind speed, and n is the number of flight data points.

[0062] In at least one embodiment of the present application, in the true airspeed calculation module, calculating the true airspeed during the flight according to the wind speed and the ground speed includes:

[0063]

[0064] Among them, V T is true air speed.

[0065] The invention has at least the following beneficial technical effects:

[0066] The airspeed system calibration method for a round-trip UAV with a fixed heading angle disclosed in the present application can reduce the impact of uneven wind fields, thereby calculating the true true airspeed during flight and completing the airspeed calibration and validity confirmation of the UAV; the true airspeed during flight is calculated with the goal of minimizing the wind speed variance for round-trip flight, thereby further reducing the requirements for wind field conditions to relax the test conditions for UAV airspeed calibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 It is a schematic diagram of the relationship between true airspeed, ground speed and wind speed during a round-trip flight with a fixed heading angle according to an embodiment of the present application. DETAILED DESCRIPTION

[0068] 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.

[0069] 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.

[0070] The following is combined with Figure 1 This application is described in further detail.

[0071] The first aspect of the present application provides a method for calibrating an airspeed system of a round-trip UAV with a fixed heading angle, comprising the following steps:

[0072] Step 1: Select a test point within the aircraft flight envelope;

[0073] Step 2: The aircraft performs a round trip flight at a fixed heading angle under the conditions corresponding to the test point, and obtains flight data of the outbound and return trips in the stable level flight stage;

[0074] Step 3: Select multiple flight data points of the outbound and return trips from the flight data, obtain the heading angle and 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 trajectory angle;

[0075] If yes, proceed to step 4;

[0076] If not, return to step 2 and re-execute the test point;

[0077] Step 4: Obtain the ground speed of each flight data point and calculate the wind speed based on the ground speed;

[0078] Step 5: Calculate the true airspeed during flight based on wind speed and ground speed;

[0079] Step 6. Calibrate the airspeed at the test point according to the true airspeed.

[0080] The present application discloses a method for calibrating the airspeed system of a round-trip UAV with a fixed heading 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 a round-trip flight under the conditions of a given aircraft configuration, flight altitude, and flight speed corresponding to the test points. When the aircraft performs a round-trip flight under the conditions corresponding to the test points, the first heading angle is kept unchanged for the outbound trip, and the second heading angle is kept unchanged for the return trip. The first heading angle for the outbound trip differs from the second heading angle for the return trip by 180°. The time for the stable level flight stage is 1 minute. The flight data of the outbound and return trips in the stable level flight stage under the conditions corresponding to the test points are recorded.

[0081] In a preferred embodiment of the present application, in step three, multiple flight data points for the outbound trip and the return trip are respectively selected from the flight data, the flight data points recorded during the stable level flight phase for the outbound trip and the return trip are substantially consistent, and n flight data points are respectively taken during the stable level flight phase for the outbound trip and the return trip.

[0082] 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:

[0083] Obtain the first heading angle and the first trajectory angle of each flight data point of the outbound journey, 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 ψ1 of each absolute value ψ1;

[0084] Obtain the second heading angle and the second trajectory angle of each flight data point of the return trip, 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 ψ2 of each absolute value ψ2;

[0085] Determine whether it is satisfied Tolerance represents a given decision threshold;

[0086] If so, the wind field unevenness during flight meets the requirements;

[0087] If not, the wind field unevenness during flight does not meet the requirements.

[0088] 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.

[0089] The airspeed system calibration method of the UAV with a fixed heading angle for round-trip flight of the present 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 ) is a vector relationship such as Figure 1 As shown, V represents speed, ψ represents the difference between heading angle and track angle, and their mathematical expressions are shown in equations (1) and (2) respectively. Among them, the subscript T represents true airspeed, G represents ground speed, W represents wind speed, 1 represents outbound trip, and 2 represents return trip; the superscript E represents eastward speed, and N represents northward speed.

[0090]

[0091]

[0092] Since the true airspeeds of the return and outbound flights are equal in magnitude and opposite in direction, the true airspeeds during the round-trip flight satisfy the relationship shown in equation (3):

[0093]

[0094] Take n flight data points in the stable level flight phase of the outbound and return flights respectively, and let:

[0095]

[0096]

[0097] According to formula (3), we have:

[0098]

[0099] Substituting equation (1) and equation (2) into The obtained expressions are shown in formula (4) and formula (5):

[0100]

[0101]

[0102] Since the wind field does not strictly meet the steady wind assumption during actual flight, therefore:

[0103]

[0104] It is not strictly true, but there must be a Minimum wind speed.

[0105] because It is essentially a quadratic function, so when equation (6) is satisfied, The value is the smallest.

[0106]

[0107] in, is the easterly wind speed, is the north wind speed, and n is the number of flight data points.

[0108] According to the above analysis, in step 4, the wind speed calculation process includes:

[0109] Get the eastbound ground speed of each flight data point on the outbound trip Northward

[0110] Get the eastward ground speed of each flight data point on the return trip Northward

[0111] Eastward ground speed Northward Eastward ground speed Northward Substitute into equation (6) to calculate the wind speed.

[0112] After obtaining the wind speed during the flight, combined with the ground speed during the flight, the true airspeed during the flight can be obtained. Finally, the true airspeed during the round-trip flight is arithmetic averaged to obtain the accurate true airspeed and complete the calibration of the airspeed system.

[0113] 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 (7).

[0114]

[0115] Among them, V T is true air speed.

[0116] 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.

[0117] The present invention discloses a method for calibrating an airspeed system of a UAV with a fixed heading angle for round-trip flight. Under the conditions of a given aircraft configuration, flight altitude, and flight speed, the aircraft completes a round-trip flight with a fixed heading angle, and the heading angle of the outbound trip and the heading angle of the return trip differ by 180°; flight data of the stable level flight phases of the outbound trip and the return trip, 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 flight data is entered into a wind speed calculation formula to calculate the wind speed during the round-trip flight; the true true airspeed is calculated based on the wind speed to complete the airspeed calibration.

[0118] The airspeed system calibration method for a round-trip UAV with a fixed heading angle in the present application calculates the true true airspeed with the goal of minimizing the wind speed variance for round-trip flight. The calculated true true airspeed has better robustness, further reducing the impact of the wind field on the airspeed calibration; 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.

[0119] Based on the above-mentioned method for calibrating the airspeed system of a round-trip UAV with a fixed heading angle, the second aspect of the present application provides a system for calibrating the airspeed system of a round-trip UAV with a fixed heading angle, comprising:

[0120] Test point selection module, used to select test points within the aircraft flight envelope;

[0121] The flight data acquisition module is used to obtain the flight data of the outbound and return trips at a stable level flight stage by making the aircraft fly back and forth at a fixed heading angle under the conditions corresponding to the test points;

[0122] The wind field unevenness determination module is used to select multiple flight data points from the flight data, obtain the heading angle and 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 trajectory angle;

[0123] If yes, then enter the wind speed calculation module;

[0124] If not, return to the flight data acquisition module and re-execute the test point;

[0125] 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;

[0126] True airspeed calculation module, used to calculate the true airspeed during flight based on wind speed and ground speed;

[0127] The airspeed calibration module is used to calibrate the airspeed at the test point according to the true airspeed.

[0128] The airspeed system calibration system for a round-trip UAV with a fixed heading angle of the present application, the functions of each module and the specific implementation method thereof, refer to the airspeed system calibration method for a round-trip UAV with a fixed heading angle mentioned above, which will not be repeated here.

[0129] 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 round-trip UAV with a fixed heading angle, characterized in that: include: Step 1: Select a test point within the aircraft flight envelope; Step 2: The aircraft performs a round trip flight at a fixed heading angle under the conditions corresponding to the test points, and obtains flight data of the outbound and return trips in the stable level flight stage; Step 3: Select multiple flight data points of the outbound trip and the return trip 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 round-trip UAV with a fixed heading 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 round-trip UAV with a fixed heading 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 round-trip UAV with a fixed heading angle according to claim 3, characterized in that: When the aircraft performs a round trip flight under the conditions corresponding to the test points, the first heading angle is kept unchanged on the outbound journey, and the second heading angle is kept unchanged on the return journey.

5. The method for calibrating the airspeed system of a round-trip UAV with a fixed heading angle according to claim 4, characterized in that: When the aircraft performs a round trip flight under the conditions corresponding to the test points, the first heading angle of the outbound trip differs from the second heading angle of the return trip by 180°.

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

7. The method for calibrating the airspeed system of a round-trip UAV with a fixed heading 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: Obtain the first heading angle and the first trajectory angle of each flight data point on the outbound journey, 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 return trip, 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 Determine whether it is satisfied 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 round-trip UAV with a fixed heading 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 eastbound ground speed of each flight data point on the outbound trip Northward Get the eastward ground speed of each flight data point on the return trip Northward Based on 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 round-trip UAV with a fixed heading 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 system for calibrating the airspeed system of a round-trip UAV with a fixed heading 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 a round trip flight at a fixed heading angle under the conditions corresponding to the test points, and to acquire flight data of the outbound and return trips in the stable level flight stage; A wind field unevenness determination module is used to select a plurality of flight data points of the outbound trip and the return trip 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; 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 a round-trip UAV with a fixed heading 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 a round-trip UAV with a fixed heading 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 a round-trip UAV with a fixed heading angle according to claim 12, characterized in that: When the aircraft performs a round trip flight under the conditions corresponding to the test points, the first heading angle is kept unchanged on the outbound journey, and the second heading angle is kept unchanged on the return journey.

14. The airspeed system calibration system for a round-trip UAV with a fixed heading angle according to claim 11, characterized in that: When the aircraft performs a round trip flight under the conditions corresponding to the test points, the first heading angle of the outbound trip differs from the second heading angle of the return trip by 180°.

15. The airspeed system calibration system for a round-trip UAV with a fixed heading angle according to claim 14, characterized in that: When the aircraft performs a round trip flight under the conditions corresponding to the test points, the time of the stable level flight phase is 1 minute.

16. The airspeed system calibration system for a round-trip UAV with a fixed heading 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: Obtain the first heading angle and the first trajectory angle of each flight data point on the outbound journey, 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 return trip, 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 Determine whether it is satisfied 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 a round-trip UAV with a fixed heading 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 eastbound ground speed of each flight data point on the outbound trip Northward Get the eastward ground speed of each flight data point on the return trip Northward Based on 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 a round-trip UAV with a fixed heading angle according to claim 17, characterized in that: In the true airspeed calculation module, 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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