Heading angle fixed round trip flight unmanned aerial vehicle airspeed system calibration method

Abstract

The application belongs to the field of unmanned aerial vehicle flight test, and particularly relates to a heading angle fixed round trip unmanned aerial vehicle airspeed system calibration method. The method comprises the following steps: step one, selecting a test point in the flight envelope of an aircraft; step two, performing round trip flight of the aircraft under conditions corresponding to the test point, and obtaining flight data of the outbound and inbound stable straight flight stages; step three, selecting multiple flight data points of the outbound and inbound from the flight data, obtaining a heading angle and a track angle of each flight data point, and judging whether the wind field uniformity in the flight process meets the requirements according to the heading angle and the track angle; if yes, entering step four; if no, returning to step two and re-executing the test point; step four, obtaining a ground speed of each flight data point, and calculating a wind speed according to the ground speed; step five, calculating a true airspeed in the flight process according to the wind speed and the ground speed; and step six, performing test point airspeed calibration according to the true airspeed.

Description

Technical Field

[0001] This application belongs to the field of unmanned aerial vehicle (UAV) flight testing, and specifically relates to a calibration method for the airspeed system of a UAV flying back and forth with a fixed heading angle. Background Technology

[0002] The accuracy of airspeed system measurements has a crucial impact on aircraft status monitoring, control, and flight safety. Most existing unmanned aerial vehicle (UAV) systems are small to medium-sized aircraft, and airspeed calibration is typically performed using the aircraft's own GPS or DGPS, with common methods including the round-trip flight method.

[0003] Because GPS-based airspeed calibration methods are highly sensitive to wind fields, it is difficult to maintain a stable wind speed in real-world experiments. Existing publicly available airspeed calibration methods do not consider the effects of wind speed inhomogeneity.

[0004] Therefore, it is desirable to have a technical solution to overcome or at least mitigate one of the aforementioned 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 UAV with a fixed heading angle for reciprocating flight, in order to solve at least one problem existing in the prior art.

[0006] The technical solution of this application is:

[0007] The second aspect of this application provides a method for calibrating the airspeed system of a UAV with a fixed heading angle during round-trip flight, comprising:

[0008] Step 1: Select test points within the aircraft's flight envelope;

[0009] Step 2: The aircraft performs round-trip flights at a fixed heading angle under the conditions corresponding to the test point, and obtains flight data during the stable level flight phase of the outbound and return journeys.

[0010] Step 3: Select multiple flight data points from the flight data for both the outbound and return journeys, and obtain the heading angle and trajectory angle of each flight data point. Based on the heading angle and trajectory angle, determine whether the wind field non-uniformity during the flight meets the requirements.

[0011] If so, proceed to step four;

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

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

[0014] Step 5: Calculate the vacuum speed during flight based on the wind speed and the ground speed;

[0015] Step 6: Calibrate the air velocity at the test point according to the vacuum velocity.

[0016] In at least one embodiment of this application, multiple test points are selected within the aircraft's flight envelope.

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

[0018] In at least one embodiment of this application, when the aircraft performs round-trip flights under the conditions corresponding to the test point, the first heading angle remains unchanged on the outbound journey and the second heading angle remains unchanged on the return journey.

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

[0020] In at least one embodiment of this application, when the aircraft performs round-trip flight under the conditions corresponding to the test point, the stable level flight phase lasts for 1 minute.

[0021] In at least one embodiment of this application, step three involves acquiring the heading angle and trajectory angle of each flight data point, and determining whether the wind field non-uniformity during flight meets the requirements based on the heading angle and trajectory angle, including:

[0022] Obtain the first heading angle and first trajectory angle for 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 for each flight data point, and then calculate the average of all absolute values ​​ψ1.

[0023] Obtain the second heading angle and second trajectory angle for each flight data point on the return journey. Calculate the absolute value ψ2 of the difference between the second heading angle and the second trajectory angle for each flight data point, and then calculate the average of these absolute values ​​ψ2.

[0024] Determine if it satisfies tolerance represents a given decision threshold;

[0025] If so, the wind field non-uniformity during flight meets the requirements;

[0026] If not, the wind field non-uniformity during flight will not meet the requirements.

[0027] In at least one embodiment of this application, step four, obtaining the ground speed of each flight data point and calculating the wind speed based on the ground speed, includes:

[0028] Obtain the eastbound ground speed of each flight data point on the outbound journey. Northward

[0029] Obtain the eastbound ground speed of each flight data point on the return journey. Northward

[0030] According to the eastward ground speed Northward Eastbound speed Northward Calculate wind speed:

[0031]

[0032] in, The wind speed is easterly. denoted as northerly wind speed, and n represents the number of flight data points.

[0033] In at least one embodiment of this application, step five, calculating the vacuum speed during flight based on the wind speed and the ground speed, includes:

[0034]

[0035] Among them, V T It is the vacuum velocity.

[0036] The second aspect of this application provides a calibration system for the airspeed system of a UAV with a fixed heading angle during round-trip flight, comprising:

[0037] The test point selection module is used to select test points within the aircraft's flight envelope;

[0038] The flight data acquisition module is used to acquire flight data during the stable level flight phase of the outbound and return journeys when the aircraft flies back and forth at a fixed heading angle under the conditions corresponding to the test point.

[0039] The wind field non-uniformity determination module is used to select multiple flight data points from the flight data for the outbound and return journeys, obtain the heading angle and trajectory angle of each flight data point, and determine whether the wind field non-uniformity during the flight meets the requirements based on the heading angle and trajectory angle.

[0040] If so, proceed to the wind speed calculation module;

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

[0042] The wind speed calculation module is used to obtain the ground speed of each flight data point and calculate the wind speed based on the ground speed.

[0043] A vacuum speed calculation module is used to calculate the vacuum speed during flight based on the wind speed and the ground speed.

[0044] The airspeed calibration module is used to calibrate the airspeed at the test point based on the vacuum speed.

[0045] In at least one embodiment of this application, multiple test points are selected within the aircraft's flight envelope.

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

[0047] In at least one embodiment of this application, when the aircraft performs round-trip flights under the conditions corresponding to the test point, the first heading angle remains unchanged on the outbound journey and the second heading angle remains unchanged on the return journey.

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

[0049] In at least one embodiment of this application, when the aircraft performs round-trip flight under the conditions corresponding to the test point, the stable level flight phase lasts for 1 minute.

[0050] In at least one embodiment of this application, the wind field non-uniformity determination module acquires the heading angle and trajectory angle of each flight data point, and determines whether the wind field non-uniformity during flight meets the requirements based on the heading angle and trajectory angle, including:

[0051] Obtain the first heading angle and first trajectory angle for 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 for each flight data point, and then calculate the average of all absolute values ​​ψ1.

[0052] Obtain the second heading angle and second trajectory angle for each flight data point on the return journey. Calculate the absolute value ψ2 of the difference between the second heading angle and the second trajectory angle for each flight data point, and then calculate the average of these absolute values ​​ψ2.

[0053] Determine if it satisfies tolerance represents a given decision threshold;

[0054] If so, the wind field non-uniformity during flight meets the requirements;

[0055] If not, the wind field non-uniformity during flight will not meet the requirements.

[0056] In at least one embodiment of this application, the wind speed calculation module acquires the ground speed of each flight data point and calculates the wind speed based on the ground speed, including:

[0057] Obtain the eastbound ground speed of each flight data point on the outbound journey. Northward

[0058] Obtain the eastbound ground speed of each flight data point on the return journey. Northward

[0059] According to the eastward ground speed Northward Eastbound speed Northward Calculate wind speed:

[0060]

[0061] in, The wind speed is easterly. denoted as northerly wind speed, and n represents the number of flight data points.

[0062] In at least one embodiment of this application, the vacuum speed calculation module calculates the vacuum speed during flight based on the wind speed and the ground speed, including:

[0063]

[0064] Among them, V T It is the vacuum velocity.

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

[0066] The airspeed system calibration method for UAVs with a fixed heading angle in this application can reduce the influence of wind field inhomogeneity, thereby calculating the true vacuum speed during flight and completing the airspeed calibration and validity verification of the UAV. The vacuum speed during flight is calculated with the goal of minimizing the wind speed variance during round-trip flight, which further reduces the requirements for wind field conditions and relaxes the test conditions for UAV airspeed calibration. Attached Figure Description

[0067] Figure 1 This is a schematic diagram showing the relationship between vacuum speed, ground speed, and wind speed during a round-trip flight with a fixed heading angle, according to one embodiment of this application. Detailed Implementation

[0068] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some, but not all, embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0069] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this application.

[0070] The following is in conjunction with the appendix Figure 1 This application will be described in further detail.

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

[0072] Step 1: Select test points within the aircraft's flight envelope;

[0073] Step 2: The aircraft performs round-trip flights at a fixed heading angle under the conditions corresponding to the test point to obtain flight data during the stable level flight phase of the outbound and return journeys.

[0074] Step 3: Select multiple flight data points from the outbound and return journeys respectively from the flight data, obtain the heading angle and trajectory angle of each flight data point, and determine whether the wind field non-uniformity during the flight meets the requirements based on the heading angle and trajectory angle.

[0075] If so, proceed to step four;

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

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

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

[0079] Step 6: Calibrate the space velocity at the test point based on the vacuum velocity.

[0080] The method for calibrating the airspeed system of a UAV with a fixed heading angle in this application includes the following steps: Step 1: Multiple test points are selected within the aircraft's flight envelope. The conditions corresponding to each test point include aircraft configuration, altitude, and speed. Multiple test points under different conditions are selected. Step 2: The aircraft performs round-trip flights under the given aircraft configuration, altitude, and speed conditions corresponding to the test points. During the round-trip flights under these conditions, the first heading angle remains unchanged on the outbound journey, and the second heading angle remains unchanged on the return journey. The difference between the first heading angle on the outbound journey and the second heading angle on the return journey is 180°. The stable level flight phase lasts for 1 minute. Flight data for both the outbound and return journeys during the stable level flight phase under the conditions corresponding to the test point are recorded.

[0081] In a preferred embodiment of this application, in step three, multiple flight data points for the outbound and return journeys are selected from the flight data. The flight data points recorded during the stable level flight phase for the outbound and return journeys are basically the same, and n flight data points are selected during the stable level flight phase for both the outbound and return journeys.

[0082] In this embodiment, the heading angle and trajectory angle of each flight data point are used to determine whether the wind field non-uniformity during flight meets the requirements, as detailed below:

[0083] 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 ψ1 of each absolute value ψ1.

[0084] Obtain the second heading angle and second trajectory angle of each flight data point on the return journey, calculate the absolute value ψ2 of the difference between the second heading angle and the second trajectory angle for each flight data point, and calculate the average value ψ2 of each absolute value ψ2.

[0085] Determine if it satisfies tolerance represents a given decision threshold;

[0086] If so, the wind field non-uniformity during flight meets the requirements;

[0087] If not, the wind field non-uniformity during flight will not meet the requirements.

[0088] During the execution of the test site, the data may become unavailable due to wind field issues. In this case, simply select a new day with good weather and conduct the flight test again (i.e., return to step two) to re-execute the test site.

[0089] This application discloses a method for calibrating the airspeed system of a UAV with a fixed heading angle during round-trip flight. After the wind field non-uniformity meets the experimental requirements during flight, wind speed is calculated. The speed during round-trip flight is analyzed; if the wind speed is stable during flight, the vacuum speed (V) is calculated. T ), wind speed (V) W ) and ground speed (V) G The vector relationship is as follows: Figure 1 As shown, V represents speed, and ψ represents the difference between the heading angle and the trajectory angle. Their mathematical expressions are shown in equations (1) and (2), respectively. In this equation, the subscript T represents vacuum speed, G represents ground speed, W represents wind speed, 1 represents the outward journey, and 2 represents the return journey; the superscript E represents eastward speed and N represents northward speed.

[0090]

[0091]

[0092] Since the vacuum velocities of the return and outward journeys are equal in magnitude and opposite in direction, the vacuum velocities during the round trip satisfy the relationship shown in equation (3):

[0093]

[0094] Take n flight data points during the stable level flight phases of both the outbound and return journeys, and let:

[0095]

[0096]

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

[0098]

[0099] Substitute equations (1) and (2) into The resulting expressions are shown in equations (4) and (5):

[0100]

[0101]

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

[0103]

[0104] It's not strictly true, but there must be something that makes it so. The wind speed with the lowest value.

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

[0106]

[0107] in, The wind speed is easterly. denoted as northerly wind speed, and n represents the number of flight data points.

[0108] Based on the above analysis, step four, the wind speed calculation process, includes:

[0109] Obtain the eastbound ground speed of each flight data point on the outbound journey. Northward

[0110] Obtain the eastbound ground speed of each flight data point on the return journey. Northward

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

[0112] After obtaining the wind speed during flight, and combining it with the ground speed, the vacuum speed during flight can be obtained. Finally, the arithmetic average of the vacuum speeds during the round trip is taken to obtain the accurate vacuum speed, thus completing the calibration of the airspeed system.

[0113] In this embodiment, in step five, the wind speed calculated in step four is used... The ground speed during the outbound and return journeys during the stable level flight phase is used to calculate the vacuum speed during the flight process. The vacuum speed during the flight process is then arithmetically averaged. Based on the calculation formula of equation (7), the true vacuum speed under given aircraft configuration, flight altitude, and flight speed conditions is finally obtained.

[0114]

[0115] Among them, V T It is the vacuum velocity.

[0116] In step six, after completing the airspeed calibration of the test point under the current aircraft configuration, flight altitude, and flight speed conditions, repeat steps two through five for the next test point in sequence until the airspeed calibration of all test points is completed.

[0117] The airspeed system calibration method for a UAV with a fixed heading angle in this application involves, under given aircraft configuration, altitude, and speed conditions, the aircraft completing one round trip with a fixed heading angle, where the heading angles of the outbound and return journeys differ by 180°; recording flight data such as altitude, speed, heading angle, and trajectory angle during the stable level flight phases of both the outbound and return journeys; calculating and determining whether the wind speed is stable based on the flight data; if the wind speed is stable, substituting the flight data into the wind speed calculation formula to calculate the wind speed during the round trip; and calculating the actual airspeed based on the wind speed to complete the airspeed calibration.

[0118] The airspeed system calibration method for UAVs with a fixed heading angle proposed in this application calculates the true vacuum speed with the goal of minimizing the wind speed variance during round-trip flight. The calculated true vacuum speed has better robustness and further reduces the influence of wind field on airspeed calibration. It also increases the requirements for wind field non-uniformity. When the wind field non-uniformity does not meet the test requirements, the test needs to be repeated. It is versatile and suitable for airspeed calibration of different types of UAVs.

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

[0120] The test point selection module is used to select test points within the aircraft's flight envelope;

[0121] The flight data acquisition module is used to acquire flight data during the stable level flight phase of the outbound and return journeys when the aircraft flies back and forth at a fixed heading angle under the conditions corresponding to the test point.

[0122] The wind field non-uniformity 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 non-uniformity during the flight meets the requirements based on the heading angle and trajectory angle.

[0123] If so, proceed to the wind speed calculation module;

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

[0125] The wind speed calculation module is used to obtain the ground speed at each flight data point and calculate the wind speed based on the ground speed.

[0126] Vacuum speed calculation module, used to calculate vacuum speed during flight based on wind speed and ground speed;

[0127] The airspeed calibration module is used to calibrate the airspeed at test points based on the vacuum speed.

[0128] The functions and specific implementation methods of each module of the airspeed system calibration system for a UAV with a fixed heading angle in this application are described in the above-mentioned calibration method for the airspeed system of a UAV with a fixed heading angle in reciprocating flight, and will not be repeated here.

[0129] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for calibrating the airspeed system of a UAV with a fixed heading angle during reciprocating flight, characterized in that, include: Step 1: Select test points within the aircraft's flight envelope; Step 2: The aircraft performs round-trip flights at a fixed heading angle under the conditions corresponding to the test point, and obtains flight data during the stable level flight phase of the outbound and return journeys. Step 3: Select multiple flight data points from the flight data for both the outbound and return journeys, and obtain the heading angle and trajectory angle of each flight data point. Based on the heading angle and trajectory angle, determine whether the wind field non-uniformity during the flight meets the requirements. If so, proceed to step four; If not, return to step two and re-execute the test point; Step 4: Obtain the ground speed at each flight data point and calculate the wind speed based on the ground speed, including: Obtain the eastbound ground speed of each flight data point on the outbound journey. Northbound ground speed Obtain the eastbound ground speed of each flight data point on the return journey. Northbound ground speed According to the eastward ground speed Northbound ground speed Eastbound speed Northbound ground speed Calculate wind speed: in, The wind speed is easterly. Here, n represents the northerly wind speed, and n represents the number of flight data points. Step 5: Calculate the vacuum speed during flight based on the wind speed and the ground speed, including: Among them, V T Vacuum speed; Step 6: Calibrate the air velocity at the test point according to the vacuum velocity.

2. The method for calibrating the airspeed system of a UAV with a fixed heading angle for reciprocating flight according to claim 1, characterized in that, The test points are selected from multiple points within the aircraft's flight envelope.

3. The method for calibrating the airspeed system of a UAV with a fixed heading angle for reciprocating flight 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 UAV with a fixed heading angle for reciprocating flight according to claim 3, characterized in that, When the aircraft performs round-trip flights under the conditions corresponding to the test point, the first heading angle remains unchanged on the outbound journey and the second heading angle remains unchanged on the return journey.

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

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

7. The method for calibrating the airspeed system of a UAV with a fixed heading angle for reciprocating flight according to claim 6, characterized in that, In step three, the heading angle and trajectory angle of each flight data point are obtained. Based on the heading angle and trajectory angle, it is determined whether the wind field non-uniformity during flight meets the requirements, including: Obtain the first heading angle and first trajectory angle for 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 for each flight data point, and then calculate the average of all absolute values ​​ψ1. Obtain the second heading angle and second trajectory angle for each flight data point on the return journey. Calculate the absolute value ψ2 of the difference between the second heading angle and the second trajectory angle for each flight data point, and then calculate the average of these absolute values ​​ψ2. Determine if it satisfies tolerance represents a given decision threshold; If so, the wind field non-uniformity during flight meets the requirements; If not, the wind field non-uniformity during flight will not meet the requirements.

8. A calibration system for the airspeed system of a UAV with a fixed heading angle during reciprocating flight, characterized in that, include: The test point selection module is used to select test points within the aircraft's flight envelope; The flight data acquisition module is used to acquire flight data during the stable level flight phase of the outbound and return journeys when the aircraft flies back and forth at a fixed heading angle under the conditions corresponding to the test point. The wind field non-uniformity determination module is used to select multiple flight data points from the flight data for the outbound and return journeys, obtain the heading angle and trajectory angle of each flight data point, and determine whether the wind field non-uniformity during the flight meets the requirements based on the heading angle and trajectory angle. If so, proceed to the wind speed calculation module; If not, return to the flight data acquisition module and re-execute the test point; The wind speed calculation module is used to acquire the ground speed at each flight data point and calculate the wind speed based on the ground speed, including: Obtain the eastbound ground speed of each flight data point on the outbound journey. Northbound ground speed Obtain the eastbound ground speed of each flight data point on the return journey. Northbound ground speed According to the eastward ground speed Northbound ground speed Eastbound speed Northbound ground speed Calculate wind speed: in, The wind speed is easterly. Here, n represents the northerly wind speed, and n represents the number of flight data points. A vacuum speed calculation module, used to calculate the vacuum speed during flight based on the wind speed and the ground speed, includes: Among them, V T Vacuum speed; The airspeed calibration module is used to calibrate the airspeed at the test point based on the vacuum speed.

9. The calibration system for the airspeed system of a UAV with a fixed heading angle for reciprocating flight according to claim 8, characterized in that, The test points are selected from multiple points within the aircraft's flight envelope.

10. The calibration system for the airspeed system of a UAV with a fixed heading angle for reciprocating flight according to claim 9, characterized in that, The conditions corresponding to the test points include aircraft configuration, flight altitude, and flight speed.

11. The calibration system for the airspeed system of a UAV with a fixed heading angle for reciprocating flight according to claim 10, characterized in that, When the aircraft performs round-trip flights under the conditions corresponding to the test point, the first heading angle remains unchanged on the outbound journey and the second heading angle remains unchanged on the return journey.

12. The calibration system for the airspeed system of a UAV with a fixed heading angle for reciprocating flight according to claim 11, characterized in that, When the aircraft performs round-trip flights under the conditions corresponding to the test point, the first heading angle of the outbound journey and the second heading angle of the return journey differ by 180°.

13. The calibration system for the airspeed system of a UAV with a fixed heading angle for reciprocating flight according to claim 12, characterized in that, When the aircraft performs round-trip flights under the conditions corresponding to the test point, the stable level flight phase lasts for 1 minute.

14. The calibration system for the airspeed system of a UAV with a fixed heading angle for reciprocating flight according to claim 13, characterized in that, In the wind field non-uniformity determination module, the heading angle and trajectory angle of each flight data point are acquired. Based on the heading angle and trajectory angle, it is determined whether the wind field non-uniformity during flight meets the requirements, including: Obtain the first heading angle and first trajectory angle for 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 for each flight data point, and then calculate the average of all absolute values ​​ψ1. Obtain the second heading angle and second trajectory angle for each flight data point on the return journey. Calculate the absolute value ψ2 of the difference between the second heading angle and the second trajectory angle for each flight data point, and then calculate the average of these absolute values ​​ψ2. Determine if it satisfies tolerance represents a given decision threshold; If so, the wind field non-uniformity during flight meets the requirements; If not, the wind field non-uniformity during flight will not meet the requirements.

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