An evtol conflict detection and collision avoidance decision method

Abstract

The application belongs to the technical field of aircraft navigation guidance and control. The application provides an eVTOL conflict detection and collision avoidance decision method. The conflict is divided into different levels and priorities by the conflict time through the horizontal direction and the vertical direction to determine whether the conflict will occur, a more reasonable collision avoidance target can be provided for the collision avoidance strategy, and the designed collision avoidance decision is adapted to the horizontal collision avoidance and vertical collision avoidance strategies according to the conflict level, and different maneuvering strategies are adaptively adopted through the collision avoidance time, so that the optimal collision avoidance strategy with small influence and short time is selected. The eVTOL can effectively identify possible threats in the airspace in a complex flight environment and provide a high-quality collision avoidance strategy with strong adaptability.

Description

TECHNICAL FIELD

[0001] Embodiments of the present disclosure relate to the technical field of aircraft navigation guidance and control, in particular to an eVTOL conflict detection and collision avoidance decision method. BACKGROUND

[0002] Although the development of eVTOL collision avoidance systems is a new project, countries around the world have long and in-depth studied the problem of large aircraft collision avoidance. From the initial secondary radar, air traffic alert, TCAS to the development of the new generation of airborne collision avoidance system ACASX (Airborne Collision Avoidance System X), the algorithms applied by these generations of large aircraft collision avoidance systems are based on geometric rules to predict the approach time and approach distance between aircrafts that may exist in the possible airspace, and then give traffic alerts (TA) and decision alerts (RA) to guide pilots to maintain or increase vertical separation. Therefore, the thinking of aircraft collision avoidance also inherits the idea and model of large aircraft air detection situation threat.

[0003] The definition of the clearance area is crucial to the establishment of the collision avoidance model and is the basis for realizing the self-separation (SS) function of the aircraft collision avoidance. In the realization of the collision avoidance function (CA) of the aircraft, it contains three key links of situation awareness, conflict prediction and conflict resolution. Many domestic and foreign scholars have studied this. Through the situation awareness and conflict prediction link, the flight state information of other aircrafts in the airspace within a certain period of time can be obtained. At present, the probability analysis method and the geometric analysis method are mainly used.

[0004] However, the probability analysis method has too large a calculation amount in actual application, which cannot meet the requirement of real-time prediction. The geometric analysis method uses a cylindrical model to obtain better results because the horizontal separation standard is much larger than the vertical separation standard in the current safety separation standard, and the sphere does not conform to the actual situation. However, the single collision risk model cannot best reflect the process of the aircraft from approaching to collision.

[0005] Therefore, it is necessary to improve one or more problems existing in the above related technical solutions.

[0006] It should be noted that this part aims to provide background or context for the technical solutions of the present disclosure stated in the claims. The description herein is not admitted to be prior art merely because it is included in this part. SUMMARY

[0007] Embodiments of the present disclosure aim to provide an eVTOL conflict detection and collision avoidance decision method, thereby at least partially overcoming one or more problems caused by limitations and defects of related technologies.

[0008] According to embodiments of the present disclosure, an eVTOL conflict detection and collision avoidance decision method is provided, which comprises:

[0009] The target position information and the target speed information of each target aircraft are obtained by the local aircraft, and the target position information and the target speed information are converted into a coordinate system in which the local aircraft is located, so as to obtain the relative position and the relative speed of the local aircraft and each target aircraft.

[0010] eVTOL conflict detection is performed according to the relative position and the relative speed, so as to determine whether the local aircraft collides with each target aircraft, and if so, the collision time is calculated.

[0011] The collision time is classified into levels, so as to obtain a collision level; wherein the collision level comprises a prevention level collision, a correction level collision and a collision avoidance level collision.

[0012] According to the collision level, a plurality of initial collision avoidance decisions are determined, the collision avoidance time of all the initial collision avoidance decisions is obtained in combination with the maneuvering characteristic information of the local aircraft, and the optimal collision avoidance decision is selected according to the collision avoidance time.

[0013] Further, in the step of obtaining the target position information and the target speed information of each target aircraft by the local aircraft, and converting the target position information and the target speed information into a coordinate system in which the local aircraft is located, so as to obtain the relative position and the relative speed of the local aircraft and each target aircraft, the step comprises:

[0014] The target position information and the target speed information of each target aircraft are obtained by the local aircraft.

[0015] The local aircraft is taken as a coordinate origin, the speed direction of the local aircraft is taken as an x-axis, the direction perpendicular to the upward direction is taken as a z-axis, the y-axis is determined according to the right-hand rule, and a coordinate system is established.

[0016] The target position information and the target speed information are converted into the coordinate system, so as to obtain the relative position and the relative speed of the local aircraft and each target aircraft.

[0017] Further, in the step of performing eVTOL conflict detection according to the relative position and the relative speed, so as to determine whether the local aircraft collides with each target aircraft, and if so, calculating the collision time, the step comprises:

[0018] obtaining relative horizontal distances between the own aircraft and each of the target aircraft according to the relative positions and relative vertical distances obtaining relative horizontal velocities between the own aircraft and each of the target aircraft according to the relative velocities and relative vertical velocities ;

[0019] comparing the relative horizontal distances with a horizontal distance threshold value ;

[0020] if the relative horizontal distance is greater than the horizontal distance threshold value , determining whether the relative horizontal velocity is directed to a clearance area of the target aircraft, if yes, indicating that a horizontal conflict will occur, if no, indicating that a horizontal conflict will not occur

[0021] if the relative horizontal distance is less than or equal to the horizontal distance threshold value , indicating that a horizontal conflict has occurred

[0022] calculating a position of entering the clearance area according to a direction of the relative velocity, obtaining a distance from the own aircraft to an intrusion point, combining the relative horizontal velocity , obtaining a horizontal conflict time ;

[0023] comparing the relative vertical distances with a vertical distance threshold value ;

[0024] if the relative vertical distance is greater than the vertical distance threshold value , determining whether the relative vertical velocity and the relative vertical distance are opposite in direction, if yes, indicating that a vertical conflict will occur, if no, indicating that a conflict will not occur

[0025] if the relative vertical distance is less than or equal to the vertical distance threshold value , indicating that a vertical conflict has occurred

[0026] obtaining a vertical conflict time according to the relative vertical velocity and the relative vertical distance ;

[0027] According to the horizontal conflict time and the vertical conflict time , the conflict time is obtained.

[0028] Further, the relative horizontal velocity is determined.

[0029]

[0030] wherein, represents the direction of the target aircraft relative to the host aircraft, represents the direction of the relative horizontal velocity, represents the relative horizontal distance between the host aircraft and the target aircraft, represents the radius of the clearance area;

[0031] The expression of the horizontal conflict time is:

[0032]

[0033] wherein, represents the relative horizontal velocity, represents the distance from the host aircraft to the intrusion point;

[0034] The expression of the vertical conflict time is:

[0035]

[0036] wherein, is the relative vertical distance.

[0037] Further, if the horizontal conflict and the vertical conflict occur simultaneously, it indicates that a conflict will occur, and the conflict time is .

[0038] Further, in the step of grading the conflict time to obtain the conflict level, the step comprises:

[0039] If the conflict time is less than or equal to a first time threshold and greater than 0, it is the collision avoidance level conflict;

[0040] If the conflict time is less than or equal to a second time threshold and greater than the first time threshold , it is the correction level conflict;

[0041] if the conflict time is greater than the second time threshold , then the prevention level conflict;

[0042] if the conflict time is equal to 0, it means that a conflict has occurred.

[0043] Further, the priority order of the conflict levels is:

[0044] the collision avoidance level conflict, the correction level conflict and the prevention level conflict.

[0045] Further, according to the conflict level, a plurality of initial collision avoidance decisions are determined, and the collision avoidance time of all the initial collision avoidance decisions is obtained in combination with the maneuvering characteristic information of the local aircraft, and the step of selecting the optimal collision avoidance decision according to the collision avoidance time comprises:

[0046] if it is determined that the prevention level conflict, the strategy of adjusting the horizontal speed is adopted, and the horizontal adjustment time of adjusting the horizontal speed is calculated in combination with the maneuvering characteristic information of the local aircraft if the horizontal adjustment time is less than the conflict time , the horizontal speed maneuvering collision avoidance strategy is used as the optimal collision avoidance strategy, otherwise the heading maneuvering collision avoidance strategy is used as the optimal collision avoidance strategy;

[0047] if it is determined that the correction level conflict or the collision avoidance level conflict, the horizontal collision avoidance time and the vertical collision avoidance time are calculated in combination with the maneuvering characteristic information of the local aircraft, respectively, and the direction with shorter collision avoidance time is selected as the optimal collision avoidance strategy.

[0048] Further, the expression of the horizontal adjustment time of adjusting the horizontal speed

[0049]

[0050] wherein, represents the speed direction of the local aircraft, represents the speed direction of the target aircraft, represents the speed of the target aircraft, represents the direction of the target aircraft relative to the local aircraft, represents the relative horizontal distance between the local aircraft and the target aircraft, represents the radius of the clearance area, is the adjusted horizontal speed, represents the maximum horizontal acceleration of the local aircraft;​

[0051] the horizontal collision avoidance time is expressed as:

[0052]

[0053] wherein, denotes the speed direction of the own aircraft, denotes the speed direction of the target aircraft, denotes the speed magnitude of the target aircraft, denotes the direction of the target aircraft relative to the own aircraft, denotes the relative horizontal distance between the own aircraft and the target aircraft, denotes the radius of the clearance area, is the adjusted speed direction of the own aircraft, denotes the maximum yaw angle rate of the own aircraft;

[0054] the vertical collision avoidance time is expressed as:

[0055]

[0056] wherein, denotes the relative vertical speed, denotes the maximum vertical acceleration of the own aircraft.

[0057] The technical solutions provided by the embodiments of the present disclosure can include the following beneficial effects:

[0058] In the embodiments of the present disclosure, through the above-mentioned eVTOL conflict detection and collision avoidance decision method, on the one hand, first, the three-dimensional position and speed information of the target aircraft in the airspace where the own aircraft is located are detected, a coordinate system is established with the own aircraft as the coordinate origin, and the position and speed information of other target aircrafts relative to the own aircraft are calculated; then, the conflict is detected by comprehensively considering the distance and time, the conflict time is calculated, and the conflict priority is divided; the aircraft with the highest conflict priority and the highest threat is preferentially selected according to the collision avoidance strategy to select the optimal collision avoidance mode. On the other hand, whether a conflict will occur is determined through the horizontal direction and the vertical direction, and the conflict is divided into different levels and priorities through the conflict time, which can provide a more reasonable collision avoidance target for the collision avoidance strategy, and the designed collision avoidance decision adaptively adopts the horizontal collision avoidance and vertical collision avoidance strategies according to the conflict level, and adaptively adopts different maneuvering strategies through the collision avoidance time, so as to select the optimal collision avoidance strategy with small influence and short time. The eVTOL can effectively identify possible threats in the airspace in a complex flight environment and provide a high-quality collision avoidance strategy with strong adaptability. BRIEF DESCRIPTION OF DRAWINGS

[0059] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate embodiments consistent with the present disclosure and, together with the description, further serve to explain the principles of the disclosure. It is to be clearly understood that the drawings are merely representative of some embodiments of the disclosure and that additional drawings can be derived from these drawings by one of ordinary skill in the art without paying creative effort.

[0060] Figure 1 A step diagram illustrating an eVTOL conflict detection and collision avoidance decision method in an exemplary embodiment of the present disclosure is shown;

[0061] Figure 2 A schematic diagram illustrating an eVTOL conflict detection flow and conflict division principle in an exemplary embodiment of the present disclosure is shown;

[0062] Figure 3 A schematic diagram illustrating a collision avoidance strategy in an exemplary embodiment of the present disclosure is shown;

[0063] Figure 4 A specific flowchart of an eVTOL conflict detection and collision avoidance decision method in an exemplary embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0064] Example implementations will now be described more fully with reference to the accompanying drawings. Example implementations may, however, be implemented in many different forms and should not be construed as limited to the implementations set forth herein; rather, these implementations are provided so that this disclosure will be thorough and complete, and will fully convey the scope of example implementations to those skilled in the art. The described features, structures, or characteristics can be combined in one or more implementations.

[0065] In addition, the accompanying drawings are included to provide a thorough understanding of embodiments of the present disclosure and are not intended to be exhaustive or to limit the present disclosure to the precise outlines described. The same or similar reference numerals in different drawings represent the same or similar elements, and thus repeated description thereof will be omitted.

[0066] An eVTOL conflict detection and collision avoidance decision method is provided in the present example implementation. Referring to FIG. 1, the eVTOL conflict detection and collision avoidance decision method can include steps S101-S104. Figure 1

[0067] Step S101: Obtain target position information and target speed information of each target aircraft using a local aircraft, and convert the target position information and the target speed information to a coordinate system in which the local aircraft is located, to obtain relative positions and relative speeds of the local aircraft and each target aircraft;

[0068] ​Step S102: performing eVTOL conflict detection according to the relative position and the relative speed to determine whether the local aircraft and each of the target aircrafts are in conflict, and if so, calculating a conflict time;

[0069] Step S103: classifying the conflict time to obtain a conflict level; wherein the conflict level includes a prevention level conflict, a correction level conflict, and a collision avoidance level conflict;

[0070] Step S104: determining a plurality of initial collision avoidance decisions according to the conflict level, combining the maneuvering characteristic information of the local aircraft to obtain collision avoidance times of all the initial collision avoidance decisions, and selecting an optimal collision avoidance decision according to the collision avoidance times.

[0071] Through the above eVTOL conflict detection and collision avoidance decision method, on the one hand, the three-dimensional position and speed information of the local aircraft and the target aircrafts in the airspace are first detected, a coordinate system is established with the local aircraft as the coordinate origin, and the position and speed information of other target aircrafts relative to the local aircraft are calculated; then, the conflict is detected by comprehensively considering the distance and time, the conflict time is calculated, and the conflict priority is classified; the aircraft with the highest conflict priority and the highest threat is preferentially selected according to the collision avoidance strategy to select the optimal collision avoidance mode. On the other hand, whether a conflict will occur is determined through the horizontal direction and the vertical direction, the conflict is classified into different levels and priorities through the conflict time, a more reasonable collision avoidance target can be provided for the collision avoidance strategy, and the designed collision avoidance decision is adaptively adopted according to the conflict level, horizontal collision avoidance and vertical collision avoidance strategies are adaptively adopted through the collision avoidance time, and different maneuvering strategies are adaptively adopted, so that the optimal collision avoidance strategy with small influence and short time is selected. The eVTOL can effectively identify possible threats in the airspace in a complex flight environment and provide a high-quality collision avoidance strategy with strong adaptability.

[0072] In the following, the above-mentioned eVTOL conflict detection and collision avoidance decision method in the present example embodiment will be described in more detail. Figures 1 to 4 The above-mentioned eVTOL conflict detection and collision avoidance decision method in the present example embodiment will be described in more detail.

[0073] In step S101, the local aircraft (i.e. the local aircraft) is taken as the coordinate origin, and the local speed direction is taken as the axis, and the vertical upward direction is taken as the axis, and the right-hand rule is used to determine the axis, and a coordinate system is established, and then the position information and speed information of other aircrafts (i.e. target aircrafts) are converted into this coordinate system.

[0074] In step S102, as shown in Figure 2 , the conflict detection is as follows:

[0075] 1) The horizontal distance between the local aircraft and the target aircraft is calculated as follows: (i.e., relative horizontal distance) and horizontal distance threshold Compare;

[0076] 2) If the horizontal distance is greater than the horizontal distance threshold, determine whether the relative horizontal speed is pointing towards the target aircraft's airspace. If so, it indicates that a horizontal conflict will occur; otherwise, it indicates that a horizontal conflict will not occur. If the horizontal distance is less than or equal to the horizontal distance threshold, it indicates that a horizontal conflict has already occurred.

[0077] If the following conditions are met:

[0078]

[0079] This indicates the relative horizontal velocity's clear airspace pointing towards the target aircraft, where... Indicates the direction of the target machine relative to the host machine. Indicates the direction of relative horizontal velocity. This indicates the horizontal distance between the local machine and the target machine. Indicates the radius of the clear airspace;

[0080] 3) Calculate the position of entering the airspace based on the direction of the relative velocity, and obtain the distance from the machine to the intrusion point. Using the magnitude of horizontal relative velocity (i.e., relative horizontal velocity) Calculate the time of horizontal conflict .

[0081] Horizontal conflict time The calculation method is as follows:

[0082]

[0083] in, Indicates the direction of the target machine relative to the host machine. Indicates the direction of relative horizontal velocity. This indicates the horizontal distance between the local machine and the target machine. Indicates the radius of the clear airspace. Indicates the magnitude of the horizontal relative velocity. This indicates the distance from the local machine to the intrusion point.

[0084] 4) Measure the vertical distance between the machine and the target machine. Vertical distance threshold Compare;

[0085] 5) If the vertical distance is greater than the vertical distance threshold, determine whether the directions of the relative vertical velocity (i.e., relative vertical speed) and the relative vertical distance (i.e., relative vertical distance) are opposite. If they are, it means that a vertical conflict will occur; otherwise, it means that no conflict will occur. If the relative vertical distance is less than or equal to the vertical distance threshold, it means that a vertical conflict has occurred.

[0086] 6) Calculate the time of vertical conflict according to relative vertical speed and relative vertical distance ; ;

[0087] 7) If both horizontal conflict and vertical conflict are determined to occur, it means that a conflict will occur, and the conflict time is ;

[0088] In step S103, the conflict is divided into a prevention level conflict, a correction level conflict, and a collision avoidance level conflict according to the conflict time, and the highest-priority collision avoidance is performed in the conflict with the highest threat.

[0089] As shown in Figure 2 , the conflict division principle is: if the conflict time is greater than the time threshold , it is a prevention level conflict, if the conflict time is less than or equal to the time threshold , and greater than the time threshold , it is a correction level conflict, if the conflict time is less than or equal to the time threshold , and greater than 0, it is a collision avoidance level conflict, and if the conflict time is equal to 0, it means that a conflict has occurred.

[0090] The conflict priority division order is: collision avoidance level conflict > correction level conflict > prevention level conflict, the threat is related to the conflict time , and the smaller the conflict time , the greater the threat.

[0091] In step S104, according to different conflict levels, the target machine with the highest priority and the greatest threat is selected, the collision avoidance time of different collision avoidance strategies is judged according to the maneuvering characteristics of the eVTOL, and the optimal collision avoidance strategy is selected;

[0092] As shown in Figure 3 , the collision avoidance strategy is: if it is determined to be a prevention level conflict, the horizontal collision avoidance strategy is used, and on the principle of trying not to change the original flight path, first calculate the time needed to adjust the horizontal speed according to the eVTOL maneuvering characteristics, if it is less than the conflict time , the speed adjustment maneuvering strategy is used, otherwise the heading adjustment strategy is used; if it is determined to be a correction level conflict or a collision avoidance level conflict, the horizontal collision avoidance time and the vertical collision avoidance time are calculated according to the eVTOL maneuvering characteristics, and the one with shorter collision avoidance time is selected as the optimal collision avoidance strategy.

[0093] The time required to adjust the horizontal velocity is calculated as follows:

[0094]

[0095] where represents the velocity direction of the ownship, represents the velocity direction of the target, represents the velocity magnitude of the target, represents the direction of the target relative to the ownship, represents the horizontal distance between the ownship and the target, represents the radius of the clearance area, is the required adjustment to the horizontal velocity, represents the maximum horizontal acceleration of the ownship.

[0096] The horizontal collision avoidance time is calculated as follows:

[0097]

[0098] where represents the velocity direction of the ownship, represents the velocity direction of the target, represents the velocity magnitude of the target, represents the direction of the target relative to the ownship, represents the horizontal distance between the ownship and the target, represents the radius of the clearance area, is the required adjustment to the ownship velocity direction, represents the maximum yaw rate of the ownship.

[0099] The vertical collision avoidance time is calculated as follows: where represents the relative vertical velocity, represents the maximum vertical acceleration of the ownship.

[0100] As shown in Figure 4 is the specific flowchart of the present application.

[0101] Through the above eVTOL conflict detection and collision avoidance decision method, on the one hand, first, the airspace where the local aircraft is located, the three-dimensional position and speed information of the target aircraft are detected, the local aircraft is taken as the coordinate origin to establish a coordinate system, and the position and speed information of other target aircrafts relative to the local aircraft are calculated; then, the conflict is detected by comprehensively considering the distance and time, the conflict time is calculated, and the conflict priority is divided; the aircraft with the highest conflict priority and the highest threat is preferentially selected to select the optimal collision avoidance mode according to the collision avoidance strategy. On the other hand, whether a conflict will occur is judged through the horizontal direction and the vertical direction, the conflict is divided into different levels and priorities through the conflict time, a more reasonable collision avoidance target can be provided for the collision avoidance strategy, and the designed collision avoidance decision adaptively adopts the horizontal collision avoidance and vertical collision avoidance strategies according to the conflict level, and adaptively adopts different maneuvering strategies through the collision avoidance time, so that the optimal collision avoidance strategy with small influence and short time is selected. The eVTOL can effectively identify the possible threats in the airspace in the complex flight environment, and provide a high-quality collision avoidance strategy with strong adaptability.

[0102] In addition, the terms "first", "second", "third", etc. are used only to describe the purpose and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first", "second", etc. can explicitly or implicitly include one or more of the features. In the description of the embodiments of the present disclosure, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified.

[0103] In the description of the present specification, the description referring to the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present disclosure. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in the present specification.

[0104] Other embodiments of the present disclosure will be apparent to those skilled in the art with the consideration of the specification and practice of the invention disclosed herein. The present application is intended to cover any variations, uses or adaptive changes of the present disclosure that follow the general principles of the present disclosure and include common knowledge or conventional techniques in the art that are not disclosed by the present disclosure. The specification and examples are only considered as exemplary, and the true scope and spirit of the present disclosure are indicated by the appended claims.

Claims

1. An eVTOL conflict detection and collision avoidance decision method, characterized in that, The method comprises: obtaining target position information and target speed information of each target aircraft by the local aircraft, and converting the target position information and the target speed information into a coordinate system in which the local aircraft is located, to obtain relative positions and relative speeds of the local aircraft and each target aircraft; performing eVTOL collision detection according to the relative positions and the relative speeds to determine whether the local aircraft collides with each target aircraft, and if so, calculating a collision time; grading the collision time to obtain a collision level; wherein the collision level comprises a prevention level collision, a correction level collision and an avoidance level collision; determining a plurality of initial collision avoidance decisions corresponding to the collision level, obtaining collision avoidance times of all the initial collision avoidance decisions in combination with maneuvering characteristic information of the local aircraft, and selecting an optimal collision avoidance decision according to the collision avoidance times; wherein in the step of obtaining target position information and target speed information of each target aircraft by the local aircraft, and converting the target position information and the target speed information into a coordinate system in which the local aircraft is located, to obtain relative positions and relative speeds of the local aircraft and each target aircraft, the step comprises: obtaining the target position information and the target speed information of each target aircraft by the local aircraft; establishing a coordinate system with the local aircraft as the coordinate origin, the speed direction of the local aircraft as the x-axis, the direction perpendicular to the upward direction as the z-axis, and the y-axis determined according to the right-hand rule; converting the target position information and the target speed information into the coordinate system to obtain the relative positions and the relative speeds of the local aircraft and each target aircraft; in the step of performing eVTOL collision detection according to the relative positions and the relative speeds to determine whether the local aircraft collides with each target aircraft, and if so, calculating a collision time, the step comprises: The relative horizontal distances between the local aircraft and each of the target aircraft are obtained based on the relative positions. and relative vertical distance The relative horizontal speeds of the local aircraft and each of the target aircraft are obtained based on the relative speeds. and relative vertical velocity ; comparing the relative horizontal distance to a horizontal distance threshold value; if the relative horizontal distance is greater than the horizontal distance threshold then determining whether the relative horizontal velocity is directed toward a clearance area of the target aircraft, and if so, indicating that a horizontal conflict will occur, and if not, indicating that a horizontal conflict will not occur; if the relative horizontal distance is less than or equal to the horizontal distance threshold then indicating that a horizontal collision has occurred; depending on the direction of the relative speed, calculating the position of entry into the clearance area, obtaining the distance of the own aircraft to the intrusion point , in combination with the relative horizontal speed , obtaining the horizontal conflict time ; comparing the relative perpendicular distance to a perpendicular distance threshold ; if the relative vertical distance is greater than the vertical distance threshold , then determining whether the relative vertical velocity and the direction of the relative vertical distance are opposite, and if so, indicating that a vertical collision will occur, and if not, indicating that a collision will not occur; if the relative vertical distance is less than or equal to the vertical distance threshold then indicating that a vertical collision has occurred; According to the relative vertical speed and the relative vertical distance , a vertical conflict time is obtained; According to the horizontal conflict time and the vertical conflict time , the conflict time is obtained; in the step of grading the collision time to obtain a collision level, the step comprises: If the conflict time is less than or equal to a first time threshold and greater than 0, then the collision is a collision of the collision level. if the conflict time is less than or equal to a second time threshold and greater than the first time threshold , then the correction level conflict if the conflict time is greater than the second time threshold then the prevention level conflict; if the conflict time is equal to 0, it means that a conflict has occurred; in the step of determining a plurality of initial collision avoidance decisions corresponding to the collision level, obtaining collision avoidance times of all the initial collision avoidance decisions in combination with maneuvering characteristic information of the local aircraft, and selecting an optimal collision avoidance decision according to the collision avoidance times, the step comprises: If the prevention level conflict is determined, a strategy of adjusting the horizontal speed is adopted, and a horizontal adjustment time of adjusting the horizontal speed is calculated in combination with the maneuvering characteristic information of the local aircraft If the horizontal adjustment time is less than the conflict time , a horizontal speed maneuvering collision avoidance strategy is used as the optimal collision avoidance strategy, otherwise a heading maneuvering collision avoidance strategy is used as the optimal collision avoidance strategy. If the conflict is determined to be either a correction-level conflict or a collision avoidance-level conflict, the horizontal collision avoidance time is calculated based on the aircraft's maneuverability information. and vertical collision avoidance time The direction with the shorter collision avoidance time is selected as the optimal collision avoidance strategy.

2. The eVTOL conflict detection and collision avoidance decision method of claim 1, wherein, determining the relative horizontal velocity an expression for the clearance volume to the target aircraft is wherein, represents the direction of the target aircraft relative to the home aircraft, represents the direction of the relative horizontal velocity, represents the relative horizontal distance of the home aircraft and the target aircraft, represents the radius of the clearance area; The horizontal conflict time The expression for the horizontal conflict time is: wherein, denotes the relative horizontal velocity, denotes the distance of the native aircraft to the intrusion point; The vertical conflict time The expression for the vertical conflict time is: wherein is the relative perpendicular distance.

3. The eVTOL conflict detection and collision avoidance decision method of claim 2, wherein, If horizontal conflict and vertical conflict occur at the same time, it means that a conflict will occur, and the conflict time is .

4. The eVTOL conflict detection and collision avoidance decision method of claim 3, wherein, the priority order of the collision level is: the avoidance level collision, the correction level collision and the prevention level collision.

5. The eVTOL conflict detection and collision avoidance decision method of claim 4, wherein, the horizontal adjustment time for adjusting the horizontal speed The expression is: wherein, represents the velocity direction of the own aircraft, represents the velocity direction of the target aircraft, represents the velocity magnitude of the target aircraft, represents the direction of the target aircraft relative to the own aircraft, represents the relative horizontal distance of the own aircraft and the target aircraft, represents the radius of the clearance area, is the adjusted horizontal velocity, represents the maximum horizontal acceleration of the own aircraft; The horizontal collision avoidance time The expression for the horizontal collision avoidance time is: wherein, represents the velocity direction of the own aircraft, represents the velocity direction of the target aircraft, represents the velocity magnitude of the target aircraft, represents the direction of the target aircraft relative to the own aircraft, represents the relative horizontal distance of the own aircraft and the target aircraft, represents the radius of the clearance area, is the adjusted own aircraft velocity direction, represents the maximum yaw angle rate of the own aircraft; The vertical collision time The expression for the vertical collision time is: wherein, represents the relative vertical speed, represents the maximum vertical acceleration of the own aircraft.

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