Conflict visualization method based on velocity vector in low-altitude operation management system

Abstract

The invention discloses a conflict visualization method based on a velocity vector in a low-altitude operation management system, which predicts a collision risk in real time by calculating a relative velocity vector of an aircraft, and displays a collision area through an enhanced visualization means. Comprising the following steps: setting parameters for each aircraft; calculating the relative position, the relative speed and the course of the relative speed, judging whether the course of the relative speed is in a collision cone or not, and calculating collision time and a collision polygon; and sorting the conflict time from large to small, sequentially drawing a speed conflict range graph under a speed reachable domain, and visually displaying the degree of the collision risk through visual elements such as color and transparency. According to the method, the low-altitude flight situation perception capability is remarkably improved, the method has the advantages of high real-time performance, good visualization effect, high accuracy, high interface cleanliness, high risk grading perception capability, high expandability and the like, and collision risks in low-altitude flight can be effectively coped with.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft, and particularly to a method for visualizing conflicts based on velocity vectors in a low-altitude operation management system. Background Art

[0002] With the gradual opening of low altitudes, the application of low-altitude aircraft has become increasingly widespread, and the flight density in low-altitude airspace has increased significantly. The low-altitude operation management mode is different from that of air transportation. Most of them adopt the distributed operation management mode of ground transportation, and the operation safety is ensured by the operating company and the operators themselves. In the urban environment, the flight environment is complex, the types of aircraft are diverse, and the flight speed and direction change frequently, which brings huge challenges to low-altitude operation management and safety. The traditional short-term conflict warning method is based on flight interval detection, which can only issue early warning and warning information, and can only generate conflict pair prompts for air traffic controllers, making it difficult to meet the real-time and complexity requirements of low-altitude flight. In addition, the traditional visualization method for conflict detection relies on track data, which can only show the current or future situation of aircraft violating the interval standard, lacks intuitive display of collision risks, and cannot meet the multi-dimensional situation awareness requirements. Although the visualization method of the solution space graph developed in Europe has certain improvements, it presents a single dangerous velocity vector area, ignores the flight envelope of the aircraft, has a lot of redundant information, and increases the perception burden of operation management personnel. The disadvantages of traditional air traffic control visualization technologies mainly focus on aspects such as unintuitive information display, lack of real-time performance, limited situation awareness ability, single visualization effect, inability to handle high-density flight environments, lack of interactivity, and inability to adapt to complex airspace environments. These disadvantages are mainly caused by technical limitations, backward design concepts, simple algorithms, system architecture limitations, etc. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for visualizing conflicts based on velocity vectors in a low-altitude operation management system. By calculating the relative velocity vectors of aircraft in real time, predicting collision risks, and displaying the collision area through enhanced visualization means, the low-altitude flight situation awareness ability is significantly improved. Compared with traditional air traffic control visualization technologies, the present invention has higher real-time performance, better visualization effects, and stronger scalability, can effectively cope with collision risks in low-altitude flight, and provides solid technical support for the modernization of air traffic control systems.

[0004] To achieve the above object, the present invention is implemented according to the following technical solutions:

[0005] The present invention includes the following steps:

[0006] S1: Set parameters such as position, velocity vector, speed range, maximum turn rate, acceleration range, and protection radius for each aircraft;

[0007] S2: Calculate the relative position, relative velocity, and the heading of the relative velocity, and determine whether the heading of the relative velocity is within the collision cone. If the condition is met, calculate the angle between the velocity vector and the position vector, the projection rate of the relative velocity onto the relative position vector, and the conflict time. When the calculated conflict time is greater than the look-ahead time, it is considered that no conflict is likely to occur within the look-ahead time, and the calculation ends. Otherwise, calculate the minimum conflict-free speed and the collision polygon, and output the conflict time and the collision polygon.

[0008] S3: With the current target as the center, draw a protection circle, calculate the heading, draw the velocity reachable domain, obtain the set of conflict times and collision polygons, sort the conflict times from largest to smallest, and successively draw the velocity conflict range diagrams under the velocity reachable domain sorted from largest to smallest conflict time, and visually display the level of collision risk through visual elements such as color and transparency.

[0009] The beneficial effects of the present invention are:

[0010] The present invention is a method for visualizing conflicts based on velocity vectors in a low-altitude operation management system. Compared with the prior art, the present invention calculates the relative velocity vectors of aircraft, predicts collision risks in real time, and displays the collision area through enhanced visualization means, significantly improving the low-altitude flight situation awareness ability. Compared with traditional technologies, the present invention has the following technical effects:

[0011] Real-time performance: By calculating the relative velocity vectors, the collision risks can be displayed in real time, meeting the real-time requirements in a high-density flight environment.

[0012] Improved visualization effect: Display information such as the positions and velocity reachable domains of aircraft in a graphical manner, and visually display the level of collision risk using different visual elements such as colors, shapes, and transparencies, helping operation and management personnel quickly understand complex airspace situations.

[0013] Accuracy: Set parameters such as protection radius, speed limit, turning limit, and acceleration limit for each aircraft to achieve accurate calculation of aircraft conflicts and accurate display of conflict risk maps, meeting the different parameter requirements of various types of low-altitude aircraft.

[0014] Improved interface cleanliness: Use the velocity reachable domain method to visually display the target movement, avoiding redundant visualization information and improving the cleanliness of the interface.

[0015] Risk classification perception: Adopt the superimposed display method of the velocity reachable domain and the conflict speed to provide risk classification perception for operation and management personnel, shortening the risk classification search time and improving the accuracy of perception.

[0016] Scalability: Applicable to multi-aircraft environments, capable of simultaneously handling collision detection for multiple aircraft, improving the scalability of the system, and effectively coping with collision risks during low-altitude flight. Description of the Drawings

[0017] Figure 1 is the flowchart of the conflict visualization method based on velocity vectors of the present invention;

[0018] Figure 2 is the flowchart of the calculation process of time to collision and collision polygon of the present invention;

[0019] Figure 3 is the flowchart of the conflict visualization graph drawing of the present invention;

[0020] Figure 4 is the conflict visualization graph (global) based on velocity vectors of the present invention;

[0021] Figure 5 is the conflict visualization graph (local) based on velocity vectors of the present invention;

[0022] Figure 5 In [figure], a is target T1, b is target T2, and C is target T3;

[0023] Figure 6 is the yellow conflict visualization graph (local) of the present invention;

[0024] Figure 7 It is that aircraft T1 intrudes into the protected area of T2 and a conflict occurs. Detailed Embodiments

[0025] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. The illustrative embodiments and descriptions of the present invention are used to explain the present invention, but do not limit the present invention.

[0026] The core idea of the present invention is to predict the relative position change between aircraft by calculating the relative velocity vectors of the aircraft, so as to achieve real-time prediction of collision risks. Specifically, the present invention first initializes the positions, velocities, and target positions of the aircraft, then calculates the relative positions and relative velocities between the aircraft, and determines whether there is a collision risk. Finally, the collision area is displayed through visualization means to assist the operation and management personnel to take measures in a timely manner.

[0027] As Figure 1 shown: The present invention includes the following steps:

[0028] S1: Set parameters such as position, velocity vector, speed range, maximum turning rate, acceleration range, and protection radius for each aircraft;

[0029] S2: Calculate the relative position, relative velocity, and the heading of the relative velocity, and determine whether the heading of the relative velocity is within the collision cone. If the condition is met, calculate the angle between the velocity vector and the position vector, the projection rate of the relative velocity onto the relative position vector, and the conflict time. When the calculated conflict time is greater than the look-ahead time, it is considered that no conflict is possible within the look-ahead time, and the calculation ends. Otherwise, calculate the minimum conflict-free speed and the collision polygon, and output the conflict time and the collision polygon;

[0030] S3: Taking the current target as the center, draw a protection circle, calculate the heading, draw the velocity reachable region, obtain the set of conflict times and collision polygons, sort the conflict times from largest to smallest, and successively draw the velocity conflict range diagrams under the velocity reachable regions sorted from largest to smallest conflict time, and visually display the level of collision risk through visual elements such as color and transparency.

[0031] In step S1, the position is Pos(x, y), the velocity vector is Vel(x, y), and the speed range is [V min , V max , where V min is the stall speed of the aircraft, set to 0 for aircraft with hovering function, and V max is the maximum flight speed of the aircraft; the maximum turning rate is w max , and the acceleration range is [Acc d , Acc a , where Acc d is the maximum deceleration rate of the aircraft in the radial direction, which is negative, and Acc a is the maximum acceleration rate of the aircraft in the radial direction, which is positive; the protection radius is R, that is, if the distance between other aircraft and this aircraft is less than this radius value, it is considered a collision occurs;

[0032] As Figure 2 shown: The specific steps of step S2 include the following steps:

[0033] S21: Initialize the output results, including setting the output polygon to NULL and the output conflict time Twarn to 10 7 s;

[0034] S22: Calculate the relative position, relative velocity, and the heading of the relative velocity. Let the current target be obj1 and the relative target be obj2. The relative position vector is δPos = obj2Pos(x, y) - obj1Pos(x, y), the relative velocity vector is δV = obj2Vel(x, y) - obj1Vel(x, y), and the relative velocity heading is φ = atan2(δVel(x), δVel(y)). Calculate the distance between the two:

[0035] S23: If rd < obj2R, then set Twarn = 0, end the calculation, and issue a collision warning.

[0036] S24: Calculate the angle between the relative target protection radius and the relative distance: α = asin(obj2R / rd), and the direction angle of the relative position: ψ = atan2(δPos(x), δPos(y)).

[0037] S25: Determine whether the relative velocity heading is within the collision cone, i.e., φ ∈ [ψ - α, ψ + α]; if this condition is not met, then it is considered that for this target, there will be no collision when running at the current speed, there is no collision risk, and the calculation ends.

[0038] S26: First, calculate the angle between the velocity vector and the position vector: β = ψ - φ, and then calculate the projection rate of the relative velocity onto the relative position vector: pV = norm(δV) / cos(β).

[0039] S27: Calculate the collision time: Twarn = (rd - obj2R) / pV. When the calculated collision time is greater than the look-ahead time, it is considered that there will be no collision within the look-ahead time, i.e., Twarn > LAT, and the calculation ends.

[0040] S28: Calculate the minimum conflict-free speed: nV = (rd - obj2R) / LAT.

[0041] S29: Calculate the collision polygon, which is a double-radius sector Verts. The angular range of the sector is: [ψ - α, ψ + α], the inner radius is: nV, and the outer radius is: rd + obj2R. Output the collision time and the collision polygon Twarn, Verts. Let the set of collision times and collision polygons corresponding to the i-th target be denoted as: Twarn i，k 、Verts i，k , k ∈ C i ,C i is the index set that conflicts with i.

[0042] As Figure 3 shown: Step S3 is to draw the protection range for all aircraft, draw the speed reachable area for the aircraft in motion, and draw the conflict range for the conflicting aircraft. Specifically, it includes the following steps:

[0043] S31: With the current target as the center and the protection radius obj R of the current target as the center, draw a protection circle.

[0044] S32: Calculate the heading tk = atan2(objVel(x), objVel(y)), and calculate the maximum angle that can be reached as: tk min = tk - LAT × wmin , the minimum angle is: tk max = tk + LAT × w max ; Calculate the minimum speed, that is: inR = max(V min , normV + LAT × Acc d ), the maximum speed is: outR = min(V max , normV + LAT × Acc a ); Draw the speed reachable domain of the target. The reachable domain is a double-radius sector, the angle range is [tk min , tk max , the radii are inR and outR, and the graph of the i-th target is denoted as: RS i ;

[0045] S32: Obtain the conflict time and the set of collision polygons Twarn i，k , Verts i，k corresponding to the target i according to steps S31 and S32. Sort the conflict time Twarn i，k from largest to smallest. The sorted index set is and sort the corresponding collision polygons accordingly. The sorted result is Take the intersection of the graph with RS i in turn, and draw the speed conflict range graph under the speed reachable domain sorted by conflict time from largest to smallest; where the color of the graph is set from yellow C0 = RGB[255, 255, 0] to red C1 = RGB[255, 0, 0], and the transparency value is set to C α = 1 - Twarn i，k / LAT, and the corresponding color value is taken as: Color = C0 + (C1 - C0) × C α .

[0046] The parameter settings for the aircraft in the present invention can set the protection radius, speed limit, turning limit, and acceleration limit for each aircraft, and can achieve accurate calculation of aircraft conflicts and accurate display of conflict risk maps. Specific solution: Utilize the characteristics of relative targets, calculate the obstacle angle, determine the relative velocity vector relationship between the target and the relative target, and calculate the collision polygon under the corresponding parameters at the same time. This avoids global parameter consistency, meets the different parameter requirements of various types of low-altitude aircraft, and improves the calculation accuracy.

[0047] The present invention visualizes the target motion in the form of a speed reachable domain, which improves the interface drawing efficiency, avoids redundant visualization information, and enhances the cleanliness of the interface compared to using the form of a solution space graph. The specific solution lies in calculating the double radii of the minimum speed and the maximum speed to set the speed reachable domain by using the acceleration limit and the aircraft flight speed limit, and obtaining the heading range that the target can reach through the angular velocity limit, thereby improving the accuracy of the speed reachable domain.

[0048] The present invention adopts the method of superimposing and displaying the speed reachable domain and the conflict speed, providing more air situation for the operation management personnel, providing risk grading perception, enhancing the accuracy of perception, and shortening the risk grading search time when facing multiple conflict risks. The specific solution lies in using the conflict time sorting, sorting the corresponding collision polygons, taking the intersection with the calculated speed reachable domain, and plotting the collision polygons under the speed reachable domain of the danger level from low to high in sequence, solving the problem of conflict grading display in the speed dimension.

[0049] In practical applications, the present invention can be widely applied to the collision detection and obstacle avoidance of low-altitude aircraft. For example, in logistics distribution, drones need to fly at low altitude in urban environments with complex flight paths and high flight densities. By using the present invention, the collision risk between drones can be predicted in real time, and the collision area can be displayed through visualization means, helping the operation management personnel to adjust the flight heading and speed in time to ensure flight safety.

[0050] In summary, the present invention calculates the relative velocity vector of the aircraft, predicts the collision risk in real time, and displays the collision area through visualization means, helping the operation personnel to take measures in time and improving flight safety. Compared with the existing methods, the present invention has higher real-time performance, better visualization effect and stronger scalability, can effectively cope with the collision risk in low-altitude flight, and provides a solid technical support for the wide application of drones and low-altitude aircraft.

[0051] Embodiment:

[0052] There are three aircraft, and their attribute initializations are shown in the following table:

[0053] The speed limits (V min , V max , m / s) are all set to: [60, 300];

[0054] The maximum turning rates (rad / s) are all set to: 0.05;

[0055] The acceleration performances (Acc d , Acc a , m / s 2 ) are all set to: [-4, 5];

[0056] Table 1 Aircraft Initialization Table

[0057]

[0058] Draw three targets according to the technical solution of the present invention as Figures 4 - 6 shown, where the green circle is the protection range of the target, the blue is the speed feasible region of the target, the red is the dangerous region of the current target speed vector, and the different transparencies and colors in the T2 target indicate that the conflict of the current T1 with T2 precedes the conflict of T3 with T2. After 2 seconds, the aircraft T1 intruded into the protection area of T2 and a conflict occurred, as Figure 7 shown.

[0059] The technical solution of the present invention is not limited to the limitations of the above specific embodiments. Any technical deformation made according to the technical solution of the present invention falls within the protection scope of the present invention.

Claims

1. A conflict visualization method based on velocity vector in a low-altitude operation management system, characterized in that: The following steps are involved: S1: Set the parameters of position, velocity vector, speed range, maximum turning rate, acceleration range and protection radius for each aircraft; S2: Calculate the relative position, relative speed and relative speed heading, and determine whether the relative speed heading is in the collision cone. If the conditions are met, calculate the angle between the speed vector and the position vector, the projection rate of the relative speed to the relative position vector and the conflict time. When the calculated conflict time is greater than the forward-looking time, it is considered that the conflict is impossible within the forward-looking time, and the calculation ends. Otherwise, calculate the minimum conflict-free rate and collision polygon, and output the conflict time and collision polygon. S3: With the current target as the center, draw a protection circle, calculate the heading, draw the speed reachable domain, obtain the conflict time and collision polygon set, sort the conflict time from large to small, and draw the speed conflict range map under the speed reachable domain after the conflict time is sorted from large to small, and intuitively display the level of collision risk through visual elements such as color and transparency.

2. The conflict visualization method based on velocity vector in the low-altitude operation management system according to claim 1 is characterized in that: In step S1, the position is Pos(x, y), the velocity vector is Vel(x, y), and the velocity range is [V min , V max ], where V min is the stall rate of the aircraft. For aircraft with hovering function, it is set to 0. V max is the maximum flight speed of the aircraft; the maximum turning rate is w max , the acceleration range is [Acc d , Acc a ], where Acc d is the maximum deceleration rate of the aircraft in the radial direction, which is a negative value. Acc a It is the maximum acceleration rate of the aircraft in the radial direction, which is a positive value. The protection radius is R, that is, if the distance between other aircraft and the aircraft is less than this radius value, it is considered that a collision has occurred. The step S2 specifically includes the following steps: S21: Initialize the output result, including setting the output polygon to NULL and the output conflict time Twarn to 10 7 s; S22: Calculate the relative position, relative velocity and relative velocity heading. Suppose the current target is obj1, the relative target is obj2, the relative position vector is δPos=obj2Pos(x, y)-obj1Pos(x, y), the relative velocity vector is δV=obj2Vel(x, y)-obj1Vel(x, y), the relative velocity heading is φ=atan2(δVel(x), δVel(y)), and calculate the distance between the two: S23: If rd<obj2R, then set Twarn=0, the calculation ends, and a conflict warning is issued; S24: Calculate the angle between the relative target protection radius and the relative distance: α=asin(obj2R / rd), the direction angle of the relative position: ψ=atan2(δPos(x), δPos(y)); S25: Determine whether the relative speed heading is within the collision cone, that is, φ∈[ψ-α, ψ+α]; if the condition is not met, it is considered that the target pair will not collide with each other at the current speed, and there is no collision risk, and the calculation ends; S26: first calculate the angle between the velocity vector and the position vector: β=ψ-φ, then calculate the projection rate of the relative velocity to the relative position vector: pV=norm(δV) / cos(β); S27: Calculate the conflict time: Twarn = (rd-obj2R) / pV. When the calculated conflict time is greater than the look-ahead time, it is considered that no conflict will occur within the look-ahead time, that is, Twarn>LAT, and the calculation ends. S28: Calculate the minimum collision-free rate: nV = (rd-obj2R) / LAT; S29: Calculate the collision polygon, which is a double-radius fan Verts. The angle range of the fan is: [ψ-α, ψ+α], the inner radius is: nV, and the outer radius is: rd+obj2R. Output the conflict time and collision polygon Twarn, Verts. Let the conflict time and collision polygon set corresponding to the i-th target be recorded as: Twarn i，k ,Verts i，k , k∈C i , C i is the set of indicators that conflict with i.

3. The conflict visualization method based on velocity vector in the low-altitude operation management system according to claim 2 is characterized in that: The step S3 specifically comprises the following steps: S31: The protection radius obj of the current target, centered on the current target R Draw a guard circle for the center of the circle; S32: Calculate the heading tk = atan2 (objVel (x), objVel (y)), and calculate the maximum angle that can be achieved: tk min =tk-LAT×w min , the minimum angle is: tk max =tk+LAT×w max ; Calculate the minimum speed: inR = max(V min ,normV+LAT×Acc d ), the maximum speed is: outR = min (V max ,normV+LAT×Acc a ); Draw the speed reachable domain of the target, which is a double-radius sector with an angle range of [tk min , tk max ], with radii inR and outR, the graph of the i-th target is recorded as: RS i ; S32: Obtain the conflict time and collision polygon set Twarn corresponding to target i according to steps S31 and S32. i，k ,Verts i，k , the conflict time Twarn i，k Sorted from large to small, the index set after sorting is And sort the corresponding collision polygons accordingly. The sorted result is: Combine graphics with RS i Take the intersections one by one, and draw the speed conflict range diagram under the speed reachable domain after the conflict time is sorted from large to small; the color of the graph is set from yellow C0 = RGB [255, 255, 0] to red C1 = RGB [255, 0, 0], and the transparency value is set to C α =1-Twarn i，k / LAT, the corresponding color value is: Color = C0 + (C1-C0) × C α .

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