A method for multi-aircraft conflict-free trajectory optimization based on air-ground negotiation

Abstract

The application provides a multi-aircraft conflict-free flight path optimization method based on air-ground negotiation, comprising the following steps: obtaining relevant information of a current aircraft, predicting a four-dimensional flight path set, and transmitting the four-dimensional flight path set to a ground control system; the ground control system obtains relevant information of other aircrafts, and predicts four-dimensional flight path sets of the other aircrafts; the ground control system performs feasibility evaluation on the four-dimensional flight path of the current aircraft; if the result of the feasibility evaluation meets the requirements, the result is uploaded to the current aircraft, the flight path selection is completed, otherwise the ground control system generates a new four-dimensional flight path and uploads the new four-dimensional flight path to the current aircraft; the current aircraft performs evaluation according to the new four-dimensional flight path, if the evaluation meets the requirements, the current aircraft performs and completes the flight path selection, otherwise the current aircraft restarts. The application provides technical support for the multi-aircraft conflict-free flight path optimization based on air-ground negotiation, and provides technical support for realizing fine control of the next generation air traffic control system.

Description

TECHNICAL FIELD

[0001] The present application relates to an aircraft flight path selection method, in particular to a multi-aircraft conflict-free flight path optimization method based on air-ground negotiation. BACKGROUND

[0002] This part provides only background information related to the present disclosure, which does not necessarily constitute prior art.

[0003] The current flight path planning and decision-making of the aircraft in flight is centered on the air traffic control agency, and the accuracy of conflict detection and identification and the demand for conflict-free trajectory generation are difficult to meet the needs of future air-ground collaborative digital operation mode of "airspace user-centered".

[0004] In terms of conflict detection and identification, the existing ground system does not consider the ontology information of the aircraft transmitted by the aircraft, and mainly relies on the minimum safety distance judgment of the predicted trajectory of the local and other aircraft in the control area obtained by the controller in the ground control system. Since the aircraft information transmitted by the aircraft is not considered, the accuracy of the obtained predicted trajectory is not high, which leads to a large false alarm in the identified conflict between aircraft, increases the risk of collision between aircraft, and increases the workload of the controller. Therefore, according to the ontology information transmitted by the aircraft, the flight trajectory and flight intention of the aircraft are analyzed, and the flight intention of the related other aircraft is considered to realize higher precision conflict detection between multiple aircraft.

[0005] In terms of aircraft conflict-free trajectory generation, the traditional conflict-free trajectory planning and generation process mainly considers the preference of the controller, but less considers the preference of the aircraft and the preference of the airline, which leads to the fact that the efficiency of the aircraft operation and the economy of the airline are not considered in the conflict-free trajectory planning process. The planned conflict-free trajectory is not optimal for the crew and the airline. In the future, based on air-ground collaborative digital operation, the autonomy of the decision-making of the aircraft and the airline needs to be increased, the interests of multiple parties need to be considered, and a conflict-free preferred trajectory that is more in line with the flight demand of the aircraft needs to be generated to further improve the efficiency of flight operation and ensure the flight safety of the flight. Therefore, the operation needs of the aircraft, the ground controller and the airline need to be better considered, and the conflict-free trajectory needs to be generated based on the analysis of the airspace environment impact, combined with the aircraft performance, airspace capacity and operation environment restrictions, to realize the multi-aircraft conflict-free optimal trajectory planning and generation under the complex constraint conditions of aircraft preference, controller preference, airline preference and operation safety.

[0006] It should be noted that the information disclosed in the above background section is only used to strengthen the understanding of the background of the present disclosure, and therefore can include information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0007] The application aims to solve the technical problem of the prior art, and provides a multi-aircraft conflict-free flight path optimization method based on air-ground negotiation.

[0008] To solve the above technical problems, the application discloses a multi-aircraft conflict-free flight path optimization method based on air-ground negotiation, which comprises the following steps:

[0009] Step 1, obtaining the relevant information of the current aircraft, predicting a four-dimensional flight path set, and downloading it to the ground control system;

[0010] Step 2, the ground control system obtains the relevant information of other aircraft, and predicts the four-dimensional flight path set of other aircraft;

[0011] Step 3, the ground control system performs feasibility evaluation of the four-dimensional flight path of the current aircraft based on the four-dimensional flight path set of the current aircraft downloaded in step 1 and the four-dimensional flight path set of other aircraft predicted in step 2;

[0012] Step 4, if the result of the feasibility evaluation in step 3 meets the requirements, the evaluation result is uploaded to the current aircraft to complete the flight path selection, otherwise step 5 is executed;

[0013] Step 5, the ground control system generates a new four-dimensional flight path and uploads it to the current aircraft;

[0014] Step 6, the current aircraft evaluates according to the new four-dimensional flight path, if it meets the requirements, the current aircraft executes and completes the flight path selection, otherwise step 1 is re-executed until the multi-aircraft conflict-free flight path optimization based on air-ground negotiation is completed.

[0015] Further, the relevant information of the current aircraft in step 1 comprises:

[0016] The state of the current aircraft, the weather condition and the aircraft intention; wherein,

[0017] The state of the current aircraft includes the current mass, thrust, resistance, position, speed and inclination angle of the aircraft;

[0018] The weather condition includes wind speed and wind direction;

[0019] The aircraft intention includes the target speed or climb rate of the aircraft.

[0020] Further, the four-dimensional flight path set predicted in step 1 is obtained by predicting the four-dimensional flight path profile set of the current aircraft through air-ground information sharing, and the specific method comprises:

[0021] The continuous points of the current aircraft flight path are predicted by integral differential equation in a preset time interval;

[0022] The air-ground information sharing is performed through the air-ground data link, that is, information is transmitted between the current aircraft and the ground control system through the air-ground data link, the real-time space dynamic, heading, ascending or descending trend of the current aircraft is identified, and a dynamic position and a four-dimensional flight trajectory profile set of the current aircraft are obtained.

[0023] Further, the information of the other aircraft in step 2 includes: flight plan information, air traffic control requirements, standard flight procedures of the aircraft, cruising altitude and speed of the aircraft, transition altitude, waypoint position, altitude, speed of the waypoint, and waypoint altitude and speed limit information.

[0024] Further, the four-dimensional trajectory set of the other aircraft predicted in step 2 includes:

[0025] Step 2-1, according to the take-off airport, landing airport, waypoint position, altitude and speed information in the flight plan information, comprehensive calculation is performed to form a horizontal trajectory, and the altitude and speed of each waypoint are determined;

[0026] Step 2-2, according to the air traffic control requirements, standard flight procedures of the aircraft, cruising altitude and speed of the aircraft, transition altitude, and waypoint altitude and speed limit information, height profile and speed profile divided into several segments are generated, and the profile and the horizontal trajectory are synthesized to obtain the four-dimensional trajectory of the other aircraft.

[0027] Further, the feasibility evaluation of the four-dimensional trajectory of the current aircraft in step 3 is performed, that is, a negotiation trajectory evaluation method for conflict management and flow balance is adopted to evaluate the feasibility of the four-dimensional trajectory of the current aircraft, including the following steps:

[0028] Step 3-1, according to the capacity of the sector, it is judged whether the sector capacity in the airspace is over capacity, the number of aircraft in the sector in the future preset time is counted, if it is greater than the sector capacity, it is over capacity, that is, it is determined that the four-dimensional trajectory of the current aircraft is not feasible, otherwise step 3-2 is executed;

[0029] Step 3-2, set negotiation priority, and get the to-be-negotiated trajectory of the current aircraft, specifically as follows:

[0030] According to the aircraft predicted airspace occupation time, from large to small, the order is sorted, and the influence of the order on the running efficiency is evaluated, and the negotiation priority of all aircraft is determined in the order from large to small; when the predicted flight volume in the preset time period is greater than the threshold value, the trajectory with large predicted airspace occupation time is preferentially selected; wherein, the calculation method of the predicted airspace occupation time attribute p is as follows:

[0031]

[0032] wherein t u represents the predicted airspace occupation time, p represents the value of the predicted occupation airspace time attribute, t u is larger, the smaller the value of p, and b represents a constant, which is a positive number;

[0033] Step 3-3, based on the method of step 3-2, obtaining all the to-be-negotiated flight paths of the aircraft according to the negotiation priority;

[0034] Step 3-4, based on the to-be-negotiated flight path, judging whether the flight intention and flight path limit of all aircrafts exist conflict, if there is conflict, the flight path is put into the infeasible flight path set, if there is no conflict, it is put into the feasible flight path set;

[0035] Further, the requirements described in step 4, i.e. the requirements of the current airspace air traffic control, include:

[0036] Flight plan limit, flow control limit, airspace limit and global situation limit.

[0037] Further, the generation of the new four-dimensional flight path described in step 5, i.e. the generation of the conflict-free four-dimensional flight path based on the airborne preference, the control preference and the airline preference, includes the following steps:

[0038] Step 5-1, using the airspace grid method to process the airspace network to generate a search space of conflict-free trajectory;

[0039] Step 5-2, adjusting the search space of conflict-free trajectory according to the airspace capacity limit and the influence of airspace environment;

[0040] Step 5-3, according to the principle of graph theory, solving the conflict-free trajectory planning model by planning the shortest flight path of the aircraft, to generate the new four-dimensional flight path.

[0041] Further, the evaluation described in step 6, i.e. the evaluation based on the flight performance limit of the aircraft, includes the following steps:

[0042] Step 6-1, taking the new four-dimensional flight path of the aircraft as input, based on the flight path limit conflict detection method of the aircraft performance, i.e. from the aircraft climb rate or descent rate, maximum turn radius and speed envelope, identifying the flight path limit pairs that exist contradictions between each other;

[0043] Step 6-2, by using the analytic hierarchy process, the ranges of the climb rate, the descent rate, the maximum turning radius and the speed of the aircraft in different flight stages are obtained by statistically analyzing the performance limits of the climb rate, the descent rate, the maximum turning radius and the speed of the aircraft in different flight stages in the collected historical flight process of the aircraft, and it is judged whether the new four-dimensional flight path of the aircraft generated in step 5 is within the range of different flight stages, if yes, it is considered that the four-dimensional flight path of the aircraft generated in step 5 has no conflict with the flight path limit, that is, the evaluation result is feasible, otherwise, it is considered that there is a conflict, that is, the evaluation result is infeasible;

[0044] Step 6-3, if the evaluation result is feasible, the aircraft executes the four-dimensional flight path of the aircraft generated in step 5, otherwise, step 1 is executed.

[0045] Further, the solving of the conflict-free trajectory planning model by planning the shortest flight path of the aircraft in step 5-3 comprises:

[0046] Step 5-3-1, according to the predicted four-dimensional flight path of the aircraft and the airspace grid;

[0047] Step 5-3-2, according to the size of the four-dimensional flight path prediction occupancy airspace time, each airspace grid is valued, and the value range is [0, 1];

[0048] Step 5-3-3, taking the current position of the aircraft as the starting point, the position expected to be reached by the aircraft in a future period of time as the ending point, and the center point of the available grid as the key vertex of the conflict-free trajectory planning, the Dijkstra shortest path algorithm is used to calculate and obtain the shortest flight path of the aircraft.

[0049] Beneficial effects:

[0050] 1. The application provides a fast implementation method for conflict-free trajectory planning based on air-ground negotiation.

[0051] 2. The application provides technical support for conflict-free planning by the airborne system.

[0052] 3. The application provides technical support for realizing trajectory fine management and control of the next generation of air-ground collaborative flight management system. BRIEF DESCRIPTION OF DRAWINGS

[0053] The above and / or other aspects of the application will become more apparent by describing in detail the preferred embodiments thereof with reference to the attached drawings.

[0054] Figure 1 is a workflow schematic diagram of an embodiment of the application.

[0055] Figure 2is a negotiation route evaluation method for conflict management and flow balancing in an embodiment of the present application.

[0056] Figure 3 is a multi-aircraft non-conflict route planning recommendation generation method based on multi-stakeholder preferences in an embodiment.

[0057] Figure 4 is a non-conflict trajectory planning diagram in a thunderstorm avoidance situation in an embodiment. DETAILED DESCRIPTION

[0058] The present application aims at the autonomous decision-making capability demand of the next generation of air navigation system based on air-ground cooperative operation, and researches a multi-aircraft non-conflict route optimization method based on air-ground negotiation automatic evaluation from the aspect of multi-route management based on air-ground shared information. The specific technical scheme is as follows: a multi-aircraft non-conflict route optimization method based on air-ground negotiation automatic evaluation, comprising the following steps:

[0059] Step 1, obtaining the relevant information of the current aircraft, predicting a four-dimensional route set, and downloading to the ground control system;

[0060] Step 2, the ground control system obtains the relevant information of other aircraft, and predicts the four-dimensional route set of other aircraft;

[0061] Step 3, the ground control system performs feasibility evaluation on the four-dimensional route of the current aircraft based on the four-dimensional route set of the current aircraft downloaded in step 1 and the four-dimensional route set of other aircraft predicted in step 2;

[0062] Step 4, if the result of the feasibility evaluation in step 3 meets the requirements, the evaluation result is uploaded to the current aircraft, the route selection is completed, otherwise step 5 is executed;

[0063] Step 5, the ground control system generates a new four-dimensional route and uploads it to the current aircraft;

[0064] Step 6, the current aircraft evaluates according to the new four-dimensional route, if it meets the requirements, the current aircraft executes and completes the route selection, otherwise step 1 is re-executed until the multi-aircraft non-conflict route optimization based on air-ground negotiation is completed.

[0065] Step 1 comprises: obtaining the state of the current aircraft, the weather condition and the aircraft intention information, wherein

[0066] The state of the current aircraft includes the current mass, thrust, resistance, position, speed and inclination angle of the aircraft;

[0067] The weather condition includes wind speed and wind direction;

[0068] The aircraft intention includes the target speed or climb rate of the aircraft.

[0069] According to the above information obtained, the four-dimensional flight trajectory profile set of the current aircraft is predicted by means of air-ground information sharing, and the four-dimensional trajectory set is predicted, and the specific method comprises the following steps:

[0070] The continuous points of the current aircraft trajectory are predicted by means of integral differential equation in a preset time interval (T i ,T i+1 ];The integral differential equation is as follows:

[0071]

[0072] Wherein,

[0073] The state vector of the aircraft in the time interval is represented, wherein

[0074]

[0075] x and y represent the horizontal and vertical axes of the horizontal position of the aircraft, h represents the height, V represents the true airspeed, γ represents the track angle, ψ represents the heading angle, φ represents the inclination angle of the aircraft, m represents the mass of the aircraft, T represents the thrust of the aircraft, D represents the drag of the aircraft, w x ,w y represent the components of the wind in the x and y directions respectively, g represents the gravitational acceleration, and η is a coefficient.

[0076] Air-ground information sharing is carried out through an air-ground data link, that is, information is transmitted between the current aircraft and the ground control system through the air-ground data link, the real-time spatial dynamics, heading, ascending or descending trend of the current aircraft are identified, and the dynamic position and four-dimensional flight trajectory profile set of the current aircraft are obtained.

[0077] The aircraft transmits the predicted dynamic position and four-dimensional flight trajectory profile set of the current aircraft to the ground control system.

[0078] Step 2 includes: the ground control system obtains the relevant information of other aircraft, including: flight plan information, air traffic control requirements, standard flight procedures of the aircraft, cruising altitude and speed of the aircraft, transition altitude, waypoint position, altitude, speed of the waypoint, and altitude and speed limit information of the waypoint.

[0079] The four-dimensional trajectory set of the other aircraft is predicted, which comprises

[0080] Step 2-1, according to the take-off airport, landing airport, waypoint position, altitude and speed information in the flight plan information, comprehensive calculation is carried out to form a horizontal trajectory, and the altitude and speed of each waypoint are determined;

[0081] Step 2-2, generating the height profile and the speed profile divided into several segments according to the requirements of air traffic control, the standard flight procedure of the aircraft, the cruising height and speed of the aircraft, the transition height and the speed limit information of the waypoint height, and synthesizing the profile and the horizontal trajectory to obtain the four-dimensional trajectory of the other aircraft.

[0082] Step 3 includes: the ground control system performs feasibility evaluation of the four-dimensional trajectory of the current aircraft based on the current aircraft four-dimensional trajectory set downloaded in step 1 and the four-dimensional trajectory set of the other aircraft predicted in step 2.

[0083] The feasibility evaluation of the four-dimensional trajectory of the current aircraft in step 3, that is, the negotiation trajectory evaluation method for conflict management and flow balancing, performs feasibility evaluation on the four-dimensional trajectory of the current aircraft, including the following steps:

[0084] Step 3-1, judging whether the sector capacity in the airspace is over capacity according to the capacity of the sector, the capacity of each sector is considered known to the control system, and the number of aircraft in the sector in the future period of time is counted, if the number of counted aircraft is greater than the capacity, it is over capacity, otherwise it is considered to be capacity balanced, if the capacity is balanced, step 3-2 is executed.

[0085] Step 3-2, from the perspective of the whole airspace, evaluating the influence on the operation efficiency according to the order of the predicted airspace occupation time of the aircraft from large to small, and determining the negotiation priority of all aircraft in the order of the predicted airspace occupation time from large to small; when the flight volume is large in a certain period of time, giving priority to the trajectory with small predicted airspace occupation time can increase the overall operation efficiency of the airspace. Similar to the cumulative waiting time attribute, the following function is used to represent the predicted airspace occupation time attribute:

[0086]

[0087] Where, t u represents the predicted airspace occupation time, p represents the value of the predicted airspace occupation time attribute, t u is larger, the value of p is smaller, b is a constant and takes a positive number;

[0088] Step 3-3, obtaining the negotiation trajectory of all aircraft based on the negotiation priority;

[0089] Step 3-4, judging whether the flight intention and the trajectory limit of all aircraft exist conflict based on the negotiation trajectory, if there is conflict, the trajectory is put into the infeasible trajectory set, if there is no conflict, it is put into the feasible trajectory set;

[0090] Step 4 comprises: if the result of the feasibility evaluation in step 3 meets the requirements of flight plan restrictions, flow control restrictions, airspace restrictions and global situation restrictions, uploading the evaluation result to the current aircraft, completing the flight path selection, otherwise executing step 5;

[0091] Step 5 comprises: the ground control system generates a new four-dimensional flight path and uploads it to the current aircraft;

[0092] The generation of the new four-dimensional flight path in step 5, i.e. the generation of a conflict-free four-dimensional flight path based on the airborne preference, the control preference and the airline preference, comprises the following steps:

[0093] Step 5-1, the airspace network is processed by using the airspace grid method to generate a conflict-free trajectory search space;

[0094] Step 5-2, the conflict-free trajectory search space is adjusted according to the airspace capacity restrictions and the airspace environment impact;

[0095] Step 5-3, according to the principle of graph theory, the conflict-free trajectory planning model is solved by planning the shortest flight path of the aircraft to generate the new four-dimensional flight path. The conflict-free trajectory planning model solving method comprises: 1) first, the predicted four-dimensional flight path of the aircraft is associated with the airspace grid; 2) according to the size of the four-dimensional flight path predicted to occupy the airspace time, each airspace grid is assigned a value, the value is in the range of [0, 1]; 3) taking the current position of the aircraft as the starting point, the position expected to be reached by the aircraft in a future period of time as the terminal point, and the vertices of the convex boundary of the unusable grid, the center points of the available grid as points, with the highest priority as the target, the Dijkstra shortest path algorithm is used to calculate and obtain the shortest flight path of the aircraft, so as to solve the conflict-free trajectory planning model.

[0096] Step 6 comprises: the current aircraft evaluates the new four-dimensional flight path, if it meets the requirements, the current aircraft executes and completes the flight path selection, otherwise re-executes step 1 until the multi-aircraft conflict-free flight path optimization based on air-ground negotiation is completed.

[0097] The evaluation in step 6, i.e. the evaluation based on the flight performance and flight restrictions of the aircraft, means that the current aircraft evaluates the feasibility of the new four-dimensional flight path uploaded in step 5, which comprises the following steps:

[0098] Step 6-1, taking the new four-dimensional flight path of the aircraft as input, based on the flight path restriction conflict detection method of the aircraft performance, i.e. from the aircraft climb rate or descent rate, maximum turning radius and speed envelope, identifying the flight path restriction pairs that exist contradictory between each other;

[0099] Step 6-2, using the analytic hierarchy process, the climbing rate, the descending rate, the maximum turning radius, the speed in different flight stages in the process of the collected aircraft history flight are statistically analyzed, the range of the climbing rate, the descending rate, the maximum turning radius, the speed in different flight stages in the process of the aircraft flight is obtained, whether the four-dimensional flight path of the aircraft generated in step 5 is within the range of different flight stages is judged, if yes, it is considered that the four-dimensional flight path of the aircraft generated in step 5 has no conflict with the flight path limit, that is, the evaluation result is feasible, otherwise, it is considered that there is a conflict, that is, the evaluation result is not feasible;

[0100] Step 6-3, if the evaluation result is feasible, the aircraft executes the four-dimensional flight path of the aircraft generated in step 5, otherwise, step 1 is executed. The aircraft performance and flight limit in step 6 includes:

[0101] The aircraft climbing limit, the flight speed envelope limit, the climbing and descending rate limit, the maximum turning rate limit, the aircraft operation whole process collision risk, the wake separation limit, the conflict risk, the aviation danger, the weather risk, the aircraft flight time, the fuel consumption, the pollution gas emission limit and the air-ground coordination limit information.

[0102] Embodiment:

[0103] The embodiment of the application discloses a multi-aircraft non-conflict flight path optimization method based on air-ground negotiation automatic evaluation, the method is applied to the improvement of the accuracy of the non-conflict trajectory planning based on air-ground negotiation, and helps to realize the fine trajectory management and control of the next generation of air traffic management system.

[0104] As Figure 1The application discloses a multi-aircraft conflict-free flight path optimization method based on air-ground negotiation automatic evaluation, and belongs to the field of air traffic management. The method firstly predicts the four-dimensional trajectories of the local aircraft and other aircrafts to form a multi-aircraft trajectory set; then, the ground control system judges whether the formed trajectory set is in conflict and whether it meets the capacity limit through a negotiation trajectory evaluation method for conflict management and flow balance based on the aircraft's predicted four-dimensional trajectory and the predicted four-dimensional trajectory of other aircrafts; if the evaluated trajectory uploaded by the airborne system meets the requirements of the ground control, the negotiation result is uploaded to the airborne system through the air-ground data link; if the evaluated trajectory uploaded by the airborne system does not meet the requirements of the ground control, the ground control generates a conflict-free four-dimensional trajectory of the aircraft based on a multi-stakeholder preference multi-aircraft conflict-free trajectory planning suggestion generation method and uploads the conflict-free four-dimensional trajectory to the airborne system; then, the airborne system performs automatic evaluation on the uploaded trajectory based on the aircraft's flight performance and flight restrictions; if the evaluation result meets the requirements of the aircraft's flight performance and flight restrictions, the aircraft executes the negotiation trajectory; if the evaluation result does not meet the requirements of the aircraft's flight performance and flight restrictions, the above steps are repeated until the optimal conflict-free four-dimensional trajectory is selected.

[0105] The application mainly aims at the conflict-free trajectory optimization technology based on air-ground cooperation, and provides technical support for the conflict-free planning of the airborne system, and the specific steps are as follows:

[0106] Step 1: Obtain the current state of the aircraft, including the current mass, thrust, drag, position, speed, tilt angle, weather conditions such as wind speed and wind direction, and aircraft intentions such as target speed or climb rate, and predict the continuous points of the current aircraft trajectory through the integral differential equation within a preset time interval (T i ,T i+1 ]; the integral differential equation is as follows:

[0107]

[0108] Wherein,

[0109] represents the state vector of the aircraft within the time interval , wherein

[0110]

[0111] x and y respectively represent the horizontal position of the aircraft, h represents the height, V represents the true airspeed, γ represents the flight path angle, ψ represents the heading angle, φ represents the tilt angle of the aircraft, m represents the mass of the aircraft, T represents the thrust of the aircraft, D represents the drag of the aircraft, w x ,wy respectively, g represents the gravity acceleration, and η is a coefficient.

[0112] The air-ground information is shared through the air-ground data link, that is, information is transmitted between the current aircraft and the ground control system through the air-ground data link, real-time spatial dynamics, heading, ascending or descending trend of the current aircraft are identified, and a dynamic position and a four-dimensional flight trajectory profile set of the current aircraft are obtained.

[0113] The aircraft transmits the predicted dynamic position and the four-dimensional flight trajectory profile set of the current aircraft to the ground control system.

[0114] Step 2: Obtain the four-dimensional trajectory set of the other aircraft by obtaining the flight plan information of the other aircraft, the requirements of air traffic control, the standard flight procedure of the aircraft, the cruising altitude and speed of the aircraft, the transition altitude, and the waypoint altitude and speed limit information; the four-dimensional trajectory set of the other aircraft mainly refers to the comprehensive formation of a horizontal trajectory according to the takeoff airport, landing airport and waypoint position, altitude, speed and other information in the planned information, and the determination of the altitude and speed of each waypoint. Then, according to the requirements of air traffic control, the standard flight procedure of the aircraft, the cruising altitude and speed of the aircraft, the transition altitude, and the waypoint altitude and speed limit (such as the control handover point, corridor entrance, etc.), a height profile and a speed profile that can be divided into several segments are generated, and the horizontal trajectory is combined to synthesize the four-dimensional trajectory of the aircraft;

[0115] Step 3: The ground control system judges whether the trajectory set formed in steps 1 and 2 exists conflict and whether it meets the capacity limit based on the four-dimensional trajectory of the aircraft transmitted by the aircraft in step 1 and the four-dimensional trajectory of the other aircraft predicted in step 2 through the negotiation trajectory evaluation method for conflict management and capacity flow balance, to realize the feasibility evaluation of the four-dimensional trajectory transmitted by the aircraft on board; the negotiation trajectory evaluation method for conflict management and capacity flow balance, as shown in the following formula, includes the following steps: Figure 2

[0116] Step 3-1, judging whether the sector capacity is over capacity according to the capacity of the sector, the capacity of each sector is considered known to the control system, by counting the number of aircraft in the sector in the future period of time, if the number of counted aircraft is greater than the capacity, it is over capacity, otherwise it is considered to be capacity balanced, if it meets the capacity balance, step 3-2 is executed;

[0117] ​Step 3-2, from the perspective of the whole airspace, evaluate the influence of operation efficiency according to the order of the predicted airspace occupation time of the aircraft from large to small, and determine the negotiation priority of all aircraft in the order of the predicted airspace occupation time from large to small; when the predicted flight volume is large in a certain time period, giving priority to the trajectory with small predicted airspace occupation time can increase the overall operation efficiency of the airspace. Similar to the cumulative waiting time attribute, the following function is used to represent the predicted airspace occupation time attribute:

[0118]

[0119] Wherein, t u represents the predicted airspace occupation time, p represents the value of the predicted airspace occupation time attribute, t u is larger, the value of p is smaller, and b represents a constant, which is a positive number;

[0120] Step 3-3, based on the negotiation priority, obtain the to-be-negotiated trajectory of all aircraft;

[0121] Step 3-4, based on the to-be-negotiated trajectory, judge whether the flight intention and trajectory limit of all aircraft exist conflict, if the conflict exists, the trajectory is put into the infeasible trajectory set, if the conflict does not exist, the trajectory is put into the feasible trajectory set;

[0122] Step 4: if the trajectory uploaded by the aircraft in step 3 meets the requirements of the ground control such as flight plan limit, flow control limit, airspace limit and global situation limit, the negotiation result is uploaded to the airborne through the air-ground data link, if the trajectory uploaded by the aircraft in step 3 does not meet the requirements of the ground control, step 5 is executed;

[0123] Step 5: based on the trajectory information uploaded by the aircraft and the predicted trajectory information of other aircraft predicted by the ground control, the ground control system generates a conflict-free four-dimensional trajectory of the aircraft based on the multi-stakeholder preference multi-aircraft conflict-free trajectory planning suggestion generation method, as shown in Figure 3 , the method comprises the following steps:

[0124] Step 5-1, the airspace grid method is used to process the airspace network to generate a search space of conflict-free trajectory;

[0125] Step 5-2, adjust the search space of conflict-free trajectory according to the airspace capacity limit and the influence of airspace environment;

[0126] Step 5-3, according to the principle of graph theory, solve the conflict-free trajectory planning model by planning the shortest flight path of the aircraft, and generate the new four-dimensional trajectory.

[0127] Among them, the solution method of the conflict-free trajectory planning model includes: 1) firstly associating the predicted four-dimensional trajectory of the aircraft with the airspace grid; 2) assigning a value to each airspace grid according to the time the four-dimensional trajectory is expected to occupy the airspace, and the assignment range is [0,1]; 3) taking the current position of the aircraft as the starting point, the position the aircraft is expected to reach in the future as the end point, and the vertex of the convex boundary of the unavailable grid and the center point of the available grid as the key vertex of the conflict-free trajectory planning, with the highest priority as the goal, using the Dijkstra shortest path algorithm to calculate the shortest flight path of the aircraft to achieve the solution of the conflict-free trajectory planning model.

[0128] Take conflict-free trajectory planning in the case of flying around a thunderstorm as an example.

[0129] First, the ground control system obtains the possible range and boundary of the thunderstorm based on meteorological information, represents the range of the thunderstorm with a convex polygon, and determines the coordinate positions of each vertex of the convex polygon;

[0130] Then the sector where the aircraft is located is rasterized, that is, the sector airspace is divided into convex polygons, generally represented by squares or rectangles, and the center position coordinates and vertex coordinates of each grid are determined;

[0131] According to the predicted time that the aircraft's four-dimensional trajectory is expected to occupy the airspace, the weight of each grid is set to [0,1]; Figure 4 As shown in the figure, p1 is the current position of the aircraft, which is the starting point, and p2 is the target point position of the aircraft. The red area in the figure is the thunderstorm area, and the aircraft needs to fly around it. The available grids around the red area are given weights according to the time the aircraft's predicted trajectory occupies the airspace. Through calculation, it can be found that the sum of the weights of the yellow path is the largest, so this path is used as the new track for flying around the thunderstorm.

[0132] Step 6: The onboard system automatically evaluates the trajectory uploaded in Step 5 (e.g., a conflict-free trajectory in the case of a thunderstorm detour) based on the aircraft's flight performance and flight limitations. Aircraft performance and flight limitations include aircraft takeoff and landing limitations, flight speed envelope, climb and descent rate, maximum turn rate, and other flight performance parameter limitations; aircraft operation risk, wake turbulence separation, conflict risk, hazardous weather risk, and other risk limitations; aircraft flight time, fuel consumption, and pollutant emissions limitations; and air-ground coordination limitations such as meteorological, air situational, and flight information.

[0133] The automatic assessment based on aircraft flight performance and flight limitations mainly includes the following steps:

[0134] Step 6-1, taking the new aircraft four-dimensional track as input, a track limit conflict detection method based on aircraft performance, that is, from the aspects of aircraft climb rate or descent rate, maximum turning radius and speed envelope, identifying track limit pairs that are contradictory to each other;

[0135] Step 6-2, using the analytic hierarchy process, by collecting the climb rate, descent rate, maximum turning radius, and speed performance limits of the aircraft in the historical flight process, obtaining the range of the climb rate, descent rate, maximum turning radius, and speed in different flight stages of the aircraft, and determining whether the aircraft four-dimensional track generated in step 5 is within the range of different flight stages. If yes, it is considered that the aircraft four-dimensional track generated in step 5 has no conflict with the track limit, that is, the evaluation result is feasible, otherwise it is considered that there is a conflict, that is, the evaluation result is not feasible;

[0136] Step 6-3, if the evaluation result is feasible, the aircraft executes the aircraft four-dimensional track generated in step 5, otherwise executes step 1. Until the multi-aircraft conflict-free track optimization based on air-ground negotiation is completed.

[0137] In a specific implementation, the present application provides a computer storage medium and a corresponding data processing unit, wherein the computer storage medium can store a computer program, and the computer program can run the invention content of a multi-aircraft conflict-free track optimization method based on air-ground negotiation and part or all steps in each embodiment provided by the present application when executed by the data processing unit. The storage medium can be a magnetic disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc.

[0138] Those skilled in the art can clearly understand that the technical solutions in the embodiments of the present application can be realized by means of a computer program and its corresponding general hardware platform. Based on such understanding, the technical solutions in the embodiments of the present application can be embodied in the form of a computer program, that is, a software product, which can be stored in a storage medium, including a plurality of instructions for causing a device (which can be a personal computer, a server, a single-chip microcomputer, an MCU or a network device, etc.) containing a data processing unit to execute the method described in each embodiment or some parts of the embodiments of the present application.

[0139] The application provides a thought and method of a multi-aircraft conflict-free path optimization method based on air-ground negotiation, and there are many methods and approaches to realize the technical scheme, and the above description is only a preferred embodiment of the application, and it should be pointed out that, for ordinary skilled in the art, some improvements and refinements can be made without departing from the principle of the application, and these improvements and refinements should also be regarded as the protection scope of the application. The components not explicitly described in the embodiment can be realized by using the prior art.

Claims

1. A method for optimizing non-conflicting multi-aircraft flight paths based on air-ground negotiation, characterized in that: The steps include: Step 1: Obtain relevant information of the current aircraft, predict a four-dimensional trajectory set, and transmit it to the ground control system; Step 2: The ground control system obtains relevant information of other aircraft and predicts the four-dimensional trajectory sets of other aircraft; Step 3: The ground control system performs a feasibility assessment of the 4D trajectory of the current aircraft based on the 4D trajectory set of the current aircraft downloaded in Step 1 and the 4D trajectory sets of other aircraft predicted in Step 2. Step 4: If the feasibility assessment result in step 3 meets the requirements, the assessment result is uploaded to the current aircraft to complete the track selection; otherwise, proceed to step 5. Step 5: The ground control system generates a new 4D trajectory and uploads it to the current aircraft. Step 6: The current aircraft is evaluated based on the new 4D trajectory. If it meets the requirements, the current aircraft executes and completes the trajectory selection. Otherwise, step 1 is repeated until the multi-aircraft non-conflicting trajectory optimization based on air-ground negotiation is completed. The feasibility assessment of the current aircraft's four-dimensional trajectory described in step 3, i.e., the feasibility assessment of the current aircraft's four-dimensional trajectory using a negotiated trajectory assessment method oriented towards conflict management and capacity flow balance, includes the following steps: Step 3-1: Determine whether the sector capacity in the airspace is exceeded based on the sector capacity. Count the number of aircraft in the sector within a preset time period. If the number of aircraft in the sector exceeds the sector capacity, the sector is exceeded, indicating that the current aircraft's 4D trajectory is infeasible. Otherwise, proceed to step 3-2. Step 3-2: Set the negotiation priority and obtain the current aircraft's track to be negotiated, as follows: The impact on operational efficiency is evaluated based on the order of the estimated airspace occupation time of the aircraft, and the negotiation priority of all aircraft is determined in this order. When the estimated flight volume in the preset time period is greater than the threshold, the track with the largest estimated airspace occupation time is preferred. The calculation method of the estimated airspace occupation time attribute p is as follows: Among them, t u represents the expected airspace occupation time, p represents the value of the expected airspace occupation time attribute, t u The larger it is, the smaller the p-value is, and b represents a constant value, which is a positive number; Step 3-3: Based on the method in step 3-2, obtain the to-be-negotiated tracks of all aircraft according to negotiation priorities; Step 3-4: Based on the trajectory to be negotiated, determine whether there is a conflict between the flight intentions of all aircraft and the trajectory restrictions. If there is a conflict, the trajectory is placed in the infeasible trajectory set; if there is no conflict, it is placed in the feasible trajectory set.

2. The method for optimizing multi-aircraft conflict-free trajectory based on air-ground negotiation according to claim 1, characterized in that: Information about the current aircraft as described in Step 1, including: Current aircraft status, weather conditions, and aircraft intentions; including, The current state of the aircraft includes the current mass, thrust, drag, position, speed, and bank angle of the aircraft; Said meteorological conditions, including wind speed and direction; The aircraft's intention, including the aircraft's target speed or rate of climb.

3. The method for optimizing multi-aircraft non-conflict trajectory based on air-ground negotiation according to claim 2, characterized in that: The four-dimensional trajectory set predicted in step 1 is obtained by predicting the four-dimensional flight trajectory profile set of the current aircraft through air-ground information sharing. The specific method includes: Predicting successive points of the current aircraft trajectory by integrating differential equations over pre-set time intervals; Air-ground information sharing is performed through the air-ground data link, that is, information is transmitted between the current aircraft and the ground control system through the air-ground data link, the real-time spatial dynamics, heading, and upward or downward trends of the current aircraft are identified, and the dynamic position and four-dimensional flight trajectory profile set of the current aircraft are obtained.

4. The method for optimizing multi-aircraft conflict-free trajectory based on air-ground negotiation according to claim 3, characterized in that: Other aircraft information described in step 2, including: flight plan information, air traffic control requirements, aircraft standard flight procedures, aircraft cruising altitude and speed, transition altitude, waypoint location, altitude, speed, waypoint altitude and speed restriction information.

5. The method for optimizing non-conflicting multi-aircraft trajectories based on air-ground negotiation according to claim 4, characterized in that: The four-dimensional trajectory set of other aircraft predicted in step 2 includes: Step 2-1, performing a comprehensive calculation based on the takeoff airport, landing airport, waypoint location, altitude, and speed information in the flight plan information to form a horizontal trajectory, and determining the altitude and speed of each waypoint; Step 2-2: Generate an altitude profile and a velocity profile divided into several segments in accordance with air traffic control requirements, the aircraft's standard flight procedures, the aircraft's cruising altitude and speed, the transition altitude, and the waypoint altitude and speed limit information. Synthesize the altitude profile and the velocity profile with the horizontal trajectory to obtain the four-dimensional trajectory of the other aircraft.

6. The method for optimizing non-conflicting multi-aircraft trajectories based on air-ground negotiation according to claim 5, characterized in that: The requirements described in step 4 are those set by ATC in the current airspace, including: Flight plan restrictions, flow control restrictions, airspace restrictions and global situation restrictions.

7. The method for optimizing non-conflicting multi-aircraft trajectories based on air-ground negotiation according to claim 6, characterized in that: The generation of a new 4D trajectory described in step 5, i.e., generating a conflict-free 4D trajectory based on the aircraft preferences, the control preferences, and the airline preferences, includes the following steps: Step 5-1: Use the spatial grid method to process the spatial network and generate a search space without conflicting trajectories; Step 5-2: Adjust the search space for conflict-free trajectories based on airspace capacity limitations and airspace environment impacts. Step 5-3, based on the principles of graph theory, solve the conflict-free trajectory planning model by planning the shortest flight path of the aircraft to generate the new four-dimensional trajectory.

8. The method for optimizing non-conflicting multi-aircraft trajectories based on air-ground negotiation according to claim 7, characterized in that: The assessment described in Step 6, i.e., based on the aircraft's flight performance limitations, includes the following steps: Step 6-1: Using the new aircraft 4D trajectory as input, a trajectory constraint conflict detection method based on aircraft performance is used to identify conflicting trajectory constraint pairs based on aircraft climb or descent rate, maximum turn radius, and speed envelope. Step 6-2: Using the analytic hierarchy process, the performance limits of the climb rate, descent rate, maximum turning radius, and speed in different flight phases collected during the aircraft's historical flight are statistically analyzed to obtain the ranges of the climb rate, descent rate, maximum turning radius, and speed in different flight phases. The ranges of the aircraft's climb rate, descent rate, maximum turning radius, and speed in different flight phases are then determined. A determination is then made as to whether the new aircraft four-dimensional trajectory generated in step 5 is within the ranges of different flight phases. If so, the aircraft four-dimensional trajectory generated in step 5 is deemed to have no conflict with the trajectory constraints, i.e., the assessment result is feasible. Otherwise, a conflict is deemed to exist, i.e., the assessment result is infeasible. In step 6-3, if the evaluation result is feasible, the aircraft executes the aircraft 4D trajectory generated in step 5, otherwise, execute step 1.

9. The method for optimizing non-conflicting multi-aircraft trajectories based on air-ground negotiation according to claim 8, characterized in that: The conflict-free trajectory planning model described in step 5-3 is solved by planning the shortest flight path for the aircraft, including: Step 5-3-1, associate the predicted 4D aircraft trajectory with the airspace grid; Step 5-3-2, assign a value to each airspace grid based on the estimated airspace occupancy time of the four-dimensional trajectory, with the value range being [0,1]; Step 5-3-3, taking the current position of the aircraft as the starting point, the position the aircraft is expected to reach in the future as the end point, and the vertices of the convex boundary of the unavailable grid, the center point of the available grid as the key vertex of the conflict-free trajectory planning, with the highest priority as the goal, use the Dijkstra shortest path algorithm to calculate and obtain the shortest flight path of the aircraft.

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