Airport apron control aircraft push-out pre-sequencing method

Abstract

The invention discloses an airport apron aircraft push-out sorting method. The method comprises the following steps: acquiring flight dynamic data and gate position distribution data of a plurality of aircrafts in a to-be-sorted aircraft set; generating a preliminary push-out sorting sequence for the to-be-sorted aircraft set; sending the preliminary push-out sorting sequence to a three-dimensional visual simulation system, carrying out sliding path planning on each aircraft based on the predicted push-out time, and carrying out conflict detection on the sliding paths of all aircrafts in a preset future time period; receiving a conflict detection result, and if the conflict detection result indicates that a path conflict exists, adjusting the preliminary push-out sorting sequence based on the conflict detection result to generate a conflict-free target push-out sorting sequence; and outputting the target push-out sorting sequence to a display interface to serve as a control instruction reference for visual display. The airport apron operation efficiency and control safety can be improved, and the airport apron control system is suitable for various airport apron operation scenes.

Description

Technical Field

[0001] This invention relates to the field of air traffic control and airport operation management technology, and in particular to a pre-sequencing method for aircraft pushback from the apron. Background Technology

[0002] Airport surface operations, particularly the management of aircraft pushback, taxiing, and taxiing out in the apron area, are among the most complex and dynamic aspects of air traffic control. Their operational efficiency directly impacts flight on-time performance, runway capacity utilization, and fuel consumption, while operational safety faces risks such as taxiing conflicts and aircraft collisions.

[0003] Currently, apron control relies primarily on the manual command and experience-based decision-making of controllers. Controllers use electronic progress sheets from the air traffic control automation system, flight schedules, and gate allocation information from the airport information integration system, combined with visual observation and air-to-ground communication, to sequence and guide aircraft pushback and taxiing. This traditional model has the following inherent drawbacks: High reliance on experience and lack of global optimization: Controllers' decisions heavily depend on personal experience, making it difficult to simultaneously perform accurate spatiotemporal simulations and global optimizations of the future taxiing paths of dozens of aircraft on the surface. Sequencing results are often based on first-come, first-served or simple priority rules, failing to systematically minimize overall pushback waiting time. This leads to underutilization of surface resources (such as taxiways and handover points), and overall operational efficiency needs improvement.

[0004] Insufficient anticipation of conflicts poses safety risks: Human judgment makes it difficult to accurately predict potential path overlaps and time conflicts among multiple aircraft in complex taxi networks (especially key nodes such as U-shaped bays and intersections) within the next 5-15 minutes. Conflicts are often only detected shortly before they occur, leaving little room for controllers to react and increasing safety risks.

[0005] Information fragmentation and lack of collaborative verification: Flight time data provided by the air traffic control system, dynamic data on aircraft positions and surface conditions provided by the airport, and actual taxiway information belong to different systems and are independent of each other. Controllers need to integrate and simulate this information in their minds, which is a heavy burden and prone to errors. Current technology lacks a tool that can integrate multi-source data and automatically rehearse and detect future operational situations in a unified, visualized 3D simulation environment.

[0006] Limitations of existing technical solutions: Some airports have applied Collaborative Decision Making (CDM) systems to calculate Target Pushback Time (TSAT). These systems are based on Target Takeoff Time (CTOT) and work backwards, focusing on meeting runway slot requirements rather than optimizing the operational flow within the apron. Such systems typically do not adequately consider the complex constraints within the apron (such as the impact of aircraft pushback on adjacent stands and the special operational rules of the bay area), nor do they achieve deep closed-loop integration with high-precision 3D surface models and real-time path conflict detection. Furthermore, they generally lack sufficient overall consideration for non-flight-related surface activities such as towing and test runs.

[0007] Therefore, the industry urgently needs an intelligent solution that can overcome the aforementioned shortcomings. This solution should be able to automatically process multi-source dynamic data, generate globally or regionally optimal push-out ranking suggestions through optimization algorithms, and utilize 3D visual simulation technology to proactively verify the ranking results against conflicts, forming a closed-loop decision-making process of intelligent calculation, simulation verification, and dynamic adjustment. This would provide controllers with intuitive, reliable, and efficient decision support, fundamentally improving the safety and efficiency of apron operations. This invention is proposed precisely to address this technical need. Summary of the Invention

[0008] To address the aforementioned technical problems, the technical solution adopted by this invention is as follows: This invention provides a pre-sequencing method for aircraft pushback from apron control, the method comprising the following steps: Obtain flight dynamic data and parking space allocation data for multiple aircraft in the set of aircraft to be sorted.

[0009] Based on the flight dynamic data, parking space allocation data, and preset apron operation constraints, a preliminary rollout sorting sequence is generated for the set of aircraft to be sorted, wherein the preliminary rollout sorting sequence includes at least the estimated rollout time of each scheduled departing aircraft.

[0010] The initial launch sequence is sent to the 3D visual simulation system so that the 3D visual simulation system can plan taxiing paths for each aircraft based on the expected launch time and perform conflict detection on the taxiing paths of all aircraft within a preset future time period.

[0011] The system receives conflict detection results from the 3D visual simulation system. If the conflict detection results indicate that there is a path conflict, the system adjusts the initial exit sorting sequence based on the conflict detection results to generate a conflict-free target exit sorting sequence.

[0012] The target is output in a sorted sequence to the display interface and visualized as a reference for control instructions.

[0013] The present invention has at least the following beneficial effects: 1. It achieves proactive conflict resolution based on 3D visual simulation, fundamentally improving apron operation safety. By deeply integrating the sorting algorithm with the 3D visual simulation system, it can accurately simulate and detect complete taxiing path conflicts of all aircraft in the future time period in digital space, thereby generating a conflict-free pushback sequence before the command is issued, eliminating unsafe events such as taxiing conflicts and scrapes at the source.

[0014] 2. A globally optimal rollout order was achieved through a multi-constraint intelligent optimization model. The sorting algorithm integrates multiple constraints such as flight schedules, gate layouts, taxiing topology, and priority rules, and performs global optimization with the goal of minimizing the total waiting time. This overcomes the limitations of manual or rule-based sorting and significantly improves the overall rollout efficiency.

[0015] 3. This invention standardizes and solidifies the optimal regulatory decision-making process, significantly improving decision-making efficiency and reproducibility. It closes off and automates the process of "data-driven sorting - 3D simulation verification - dynamic feedback adjustment," transforming complex global decisions into stable and reproducible system outputs, thus freeing regulatory decisions from excessive reliance on personal experience.

[0016] 4. It provides controllers with intuitive and accurate intelligent decision support, effectively reducing their workload. The final generated conflict-free optimized sequence is clearly presented through a visualization interface that integrates electronic progress sheets and 3D situational awareness, providing controllers with intuitive instruction references and greatly reducing the cognitive burden and operation time of information sorting, conflict assessment, and manual sequencing.

[0017] 5. Specific optimizations have been made for complex operating scenarios (such as U-shaped harbors), enhancing practical adaptability and robustness. By defining special constraints such as exclusive use rules for key resources, it can intelligently handle various complex bottlenecks in apron operations, ensuring the safety and feasibility of the optimized solution in real-world complex environments.

[0018] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1A flowchart of a pre-sorting method for aircraft pushback from apron control provided in an embodiment of the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0023] It should be noted that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe the steps as sequential processes, many of these steps can be performed in parallel, concurrently, or simultaneously. Furthermore, the order of the steps can be rearranged. A process can be terminated when its operation is complete, but it may also have additional steps not included in the figures. A process can correspond to a method, function, procedure, subroutine, subroutine, etc.

[0024] To overcome the shortcomings of existing technologies in apron control, which rely on manual experience and lack global optimization and proactive conflict detection, this invention provides a pre-sequencing method for aircraft pushback in apron control. This method aims to optimize the pushback order and improve operational efficiency and safety through intelligent decision support. Figure 1 The main flow of one embodiment of the method is shown, which includes the following steps: S100: Obtain flight dynamic data and parking space allocation data for multiple aircraft in the set of aircraft to be sorted.

[0025] The flight dynamic data includes: (1) Time node data: Calculated takeoff time (CTOT), calculated wheel chock removal time (COBT), target wheel chock removal time (TOBT), estimated wheel chock removal time (EOBT), and planned wheel chock removal time (SOBT / ETD) obtained from the air traffic control collaborative decision-making system; and actual times reflecting the progress of flight support obtained from the airport operation system, such as actual cabin door closing time, actual passenger boarding end time, actual wheel chock removal time, and current system time. (2) Progress Slip Data: Electronic progress slip status data obtained from the air traffic control tower automation system, including: Inbound flight status: Pre-Arrival Control (PRE), Contacted Tower (CTL), Taxis on the Ground (TXI), On-site Position (OVE), Go-around (MIS), etc.; Departure flight status: Request for release (REO), Waiting for release (WAT), Released (CLD), Ready (RDY), Not yet pushed back (NPU), Pushback (PUS), Taxiing (TTX), etc. Towing task status: towing application, approval, start, completion, etc. (linked and verified with ACDM system task progress data); Status verification requirements: All status data must include a timestamp to ensure the accuracy of the "status-time" mapping relationship and provide a basis for sorting time sequence calculations.

[0026] (3) Operational status data: real-time taxiing status of arriving and departing flights, gate occupancy status, and towing task execution progress, etc.

[0027] The parking stand allocation data includes parking stand allocation status data, parking stand attribute data, and parking stand spatial layout data obtained from the airport information integration system. The parking stand allocation status data includes: Basic allocation information: current occupancy status (occupied / idle) of each parking stand, occupied flight number, planned arrival time, planned departure time, actual arrival time, etc. Dynamically adjust data: temporary changes in parking positions, backup parking position allocation plan, changes in parking position occupancy time due to flight delays / advances, etc. Related constraint information: the limitations of the aircraft stand itself when entering / leaving (such as aircraft type compatibility limitations, departure direction limitations), and the scope of influence on surrounding aircraft stands (such as adjacent avoidance requirements when leaving aircraft stands in the harbor area).

[0028] The station attribute data includes: Basic attributes: gate number, area (e.g., near gate / remote gate, Northeast apron / Hainan Airlines apron, etc.), aircraft types and categories (C / D / E / F, etc.), airline-specific attributes, etc. Support capability attributes: whether it supports bridge docking, whether it has the conditions for towing operations, and the type of ground support equipment it can adapt to; Restrictive attributes include: special restrictions in the harbor area, spatial constraints for large aircraft entering / departing, and mutual exclusion rules for simultaneous operation of adjacent aircraft positions.

[0029] Spatial layout data includes: Geometric information: GIS basic data such as parking position coordinates, geometric shape, floor area, and parking position boundary range; Topological connectivity: connection nodes with surrounding taxiways, access to taxiway segments (such as micro-segments like J2_01 / J2_02), spatial distance and clearance between adjacent parking positions; Key location information: Coordinates and relationships of launch start point, taxi access point, and handover point (handover location between apron control and ground control), supporting path time calculation.

[0030] The composition of the set of aircraft to be sorted follows the inclusion scope and time window defined by the pre-sorting function to ensure that the sorting calculation covers dynamic objects across the entire apron operation scenario. Specifically, this set includes, but is not limited to, the following aircraft: For aircraft scheduled to depart: Flights that are scheduled to take off within the preset time window and meet the following criteria: "30 minutes before departure", "already in the preparation stage (including CLD released, RDY ready, and NPU not yet pushed out)" and "not yet taken off (no TTX / ATX status)" will be subject to core participation in the pushback order optimization. Aircraft scheduled to arrive at the port: Flights that are expected to arrive within the preset time window and meet the following conditions must be included in the entire taxiing and parking process sequence: "30 minutes before landing", "have contacted the tower (CTL status)" and "have not yet entered the parking position (OVE status)". For planned towing missions involving aircraft: aircraft whose mission status is "Agreed" or "Started" and whose planned time is within 30 minutes before or after the current time, the impact of their towing path and resource occupation must be considered simultaneously.

[0031] Supplementary objects: aircraft that have been pushed back into operation or are taxiing (aircraft currently performing taxiing operations at the airport), whose current taxiing time window is included in the calculation as a fixed constraint.

[0032] S200, based on the flight dynamic data, parking space allocation data and preset apron operation constraints, generates a preliminary sorting sequence for the set of aircraft to be sorted.

[0033] This step, based on the flight dynamics data, parking space allocation data, and preset apron operation constraints obtained in step S100, generates a safe preliminary rollout sorting sequence for the set of aircraft to be sorted by solving an optimization problem that incorporates the preset apron operation constraints. This preliminary rollout sorting sequence includes at least the estimated rollout time of each scheduled departing aircraft.

[0034] To address the technical characteristics of the pre-sorting problem (which includes continuous variables such as "aircraft pushback time" and discrete decision variables such as "taxiing resource occupancy"), a mixed-integer linear programming (MILP) model is used to construct the core optimization framework. This model is the standard solution in the industry for solving "combinatorial optimization problems with hard constraints". Compared with black-box models, it can explicitly transform all apron operation business rules into mathematical constraints, ensuring that the solution results are interpretable, controllable, and can be stably deployed, which fully meets the requirements of airport production systems for compliance and maintainability.

[0035] Specifically, this step achieves intelligent sorting by solving a constrained optimization problem. The core objective of this optimization model is to minimize the overall pushback waiting time of all scheduled departing aircraft. The overall pushback waiting time is defined as the sum of the differences between the estimated pushback time of each scheduled departing aircraft and its corresponding ready or cleared time.

[0036] In one embodiment, the objective function of this optimization model can be quantified as: Min Σ i=1 n (Tpush i -Tready i ).

[0037] Among them, Tpush i For the estimated launch time of the i-th scheduled departing aircraft, Tready i The accurate readiness reference time is the time when the i-th scheduled departing aircraft is ready or authorized for departure, and its value is determined according to the following rules: If the aircraft is in the CLD (Clearly Released) status (determined based on electronic progress slip data from the air traffic control tower automation system), then Tready i Take the effective time of air traffic control release, which is the later value between the "Release Request Time (T-REQ)" in the electronic progress form and the release approval time; If the aircraft is in the Ready state (RDY state) but has not been released, then Ready i The target wheel chock removal time (TOBT, obtained from the air traffic control CDM or NTFM system) is the estimated time for the aircraft to complete all ground support work, including closing the passenger cabin door, closing the cargo door, evacuating the departure bridge or passenger boarding bridge, and placing the trolley in place. If the aircraft has a calculated takeoff time (CTOT, obtained from the flight flow management system), then Tready i The adjustment needs to be made by combining the CTOT and the estimated departure taxiing time to calculate a reasonable advance window. The adjustment formula is: Tready i (C) = max(Tready) i CTOT i-Ttax i (out), where, Tready i (C) is the revised preparation readiness reference time for the i-th scheduled departing aircraft, Ttax i (out) represents the estimated departure taxiing time for the i-th scheduled departing aircraft (calculated based on the topological distance between the parking stand and the takeoff runway and the default taxiing speed of 20 km / h, or using the historical average taxiing time calculated by the ACDM system). CTOT i The calculated takeoff time is for the i-th scheduled departing aircraft.

[0038] The value of i ranges from 1 to n, where n is the total number of aircraft scheduled to depart in the set of aircraft to be sorted; (Tpush i -Tready i The value ) represents the waiting time of a single aircraft, and Min represents the sum of the pushback waiting times of all scheduled departing aircraft, minus the minimum operation. The optimization model must satisfy the constraints defined by the operational logic and physical laws of the apron, mainly including: (1) Spatiotemporal conflict constraint: For any two different aircraft p and q in the set of aircraft to be sorted (p and q can be aircraft scheduled to depart, aircraft scheduled to arrive, or aircraft involved in towing tasks, respectively), if the planned taxiing paths of aircraft p and aircraft q share resources, the time window for aircraft p to occupy the shared resources shall not overlap with the time window for aircraft q to occupy the shared resources, and a safety interval buffer time of not less than 1 minute shall be reserved. The shared resources include those determined based on the following topology model: The core definition of the topology model is as follows: the airport surface taxiway path is constructed using a "node-segment" model, which defines the physical intersections of the taxiway, runway warning positions, intermediate holding positions, and curve vertices as key nodes; the taxiway segment between two adjacent key nodes is defined as the basic segment; if the length of the basic segment exceeds a preset threshold (default 200 meters), virtual nodes are inserted at preset intervals (default 50 meters) to divide it into multiple sub-segments (taxiway micro-segments); shared resources include the above sub-segments, key nodes, handover points, and the taxiway area around the aircraft stand.

[0039] The calculation rules for the time window are as follows: The start time of the time window = the estimated time when the aircraft will arrive at the origin of the shared resource; Time window end time = start time + resource usage duration + safety interval buffer time; Resource occupation duration: Micro-segment occupation duration = Micro-segment length / Configured coasting speed (default 20km / h, can be dynamically adjusted according to aircraft model); Critical node occupation duration = Safe passage time (default 30 seconds) + Observation and waiting time (default 30 seconds). The types of conflicts to be avoided include cross-traffic conflicts, head-on conflicts, and rear-end collisions.

[0040] (2) Runtime priority constraints, including: Arrival Priority Constraint: For any arriving aircraft r and any scheduled departing aircraft s in the set of aircraft to be sorted, if there is an intersection point (including shared micro-segments, intersection nodes, and avoidance areas around the parking stand) between the planned taxiing paths of aircraft r and aircraft s, then the estimated pushback time of aircraft s should be later than the estimated time of aircraft r passing through the intersection point. The estimated time of aircraft r passing through the intersection point is equal to the path time from the current taxiing position of the aircraft r to the intersection point plus the current system time (calculated based on the real-time taxiing status in the flight dynamics data).

[0041] Weight constraint for released flights: The waiting time of planned departing aircraft that have obtained release permission (CLD status) has a weight coefficient of 1.5 in the objective function (the weight coefficient for unreleased flights is 1.0). During iterative optimization, the waiting time of this type of aircraft should be reduced first.

[0042] (3) Supplementary constraints on physical and business rules ① Resource exclusivity constraint: At any given time, only one aircraft is allowed to occupy a single taxiway micro-segment or key node; ② Aircraft stand operation constraints: The time window for pushing back aircraft stands in the harbor area must allow for clearance from adjacent aircraft; the resource occupation time window for large E / F category aircraft is adjusted by a factor of 1.2. ③ Towing task constraints: The towing path must avoid the main taxiing path of the flight, and the time window includes the entire time period of tractor connection, towing, and disengagement.

[0043] ④ Latest pushback time constraint: The estimated pushback time for each scheduled departing aircraft must not be later than the difference between its calculated takeoff time and the estimated taxiing time for departure, i.e., Tpush. i ≤(CTOT i -Ttax i (out) ensures that after the aircraft pushes out, it can complete the departure taxiing as planned and arrive at the runway, ensuring the normal takeoff of the flight.

[0044] This invention uses PuLP as the modeling and solver calling tool for MILP models. The specific execution logic is as follows: (1) Transform the business objective of “minimizing the overall rollout waiting time” into a linear objective function; (2) Transform all hard constraints, such as spatiotemporal conflict constraints, operation priority constraints, physical and business rule constraints, into standard linear / integer programming constraint expressions; (3) Based on the PuLP interface, the above objective function and constraints are encapsulated to generate an MILP model file that conforms to industry standards.

[0045] In this invention, the completed MILP model is submitted to the underlying MILP solver (such as CBC, Gurobi, etc.) for global optimization. The global optimization means that the solver does not use a local greedy strategy to generate an approximate solution, but systematically searches within the space of all feasible solutions that satisfy the constraints, and finally outputs a provable global optimal solution (or outputs an approximate optimal solution with optimal bounds under a preset time / accuracy threshold). This ensures the stability, interpretability, and reproducibility of the ranking results, and avoids problems such as high waiting time and increased conflict risk caused by local optima.

[0046] This invention employs a heuristic search algorithm, taking the initial derived sequence (the globally optimal solution obtained by MILP) as the starting point for iteration, and iteratively executes the process of "candidate sequence generation - sequence evaluation - solution update" until the iteration termination condition is met. Specifically, it includes the following steps: S210, based on the readiness time of each aircraft scheduled to depart, generates an initial sequence, specifically including: Data preprocessing: Integrating readiness time, CTOT, COBT (calculation of wheel chock removal time) from flight dynamic data, and information such as the area to which the parking stand belongs, aircraft type compatibility, and taxiway topology priority from parking stand allocation data; Priority scoring: A priority score is calculated for each aircraft scheduled to depart. The scoring rule is: Priority score = (30 - (Readiness time - Current system time) / 60) × 30% + (20 points if the aircraft is in CLD status, otherwise 0 points) + (the shorter the CTOT time, the higher the score, with a weight of 40%) + (10 points if the aircraft stand is close to the main taxiway, otherwise 0 points). Sequence generation: Sort by priority score from high to low to generate the initial exit sequence; if the scores are the same, sort by readiness time, with earlier readiness time appearing first.

[0047] S220, employing a heuristic search algorithm, starts from the initial sequence and iteratively executes the following process: generating new candidate sequences, evaluating whether the candidate sequences satisfy the constraints and the total release waiting time of the candidate sequences. Specifically, it includes the following steps: S2201, for each aircraft in an evaluation sequence, calculates the complete taxiing path of the aircraft from the origin to the destination based on the path planning strategy, and calculates the precise time window for the aircraft to occupy each path resource based on the aircraft's expected launch time in the evaluation sequence.

[0048] For each aircraft in an evaluation sequence, based on a three-level path planning strategy of "prioritizing the use of predefined fixed taxiways → automatically planning the shortest path if no predefined route is available → path constraint verification and adjustment", and combined with the sub-segments and key node resource information of the topology model, the complete taxiway path of the aircraft from the starting position to the destination (target handover point / runway) is calculated. Based on the aircraft's expected pushback time in the evaluation sequence, combined with the length of each sub-segment, the configuration taxi speed dynamically adjusted according to the scenario, the passage time of key nodes set by category, and the differentiated safety interval buffer time, the precise time window (including start time, end time, and safety interval buffer time) of the aircraft occupying each path resource is calculated by recursion.

[0049] The path planning is performed in the following three steps: The first step is to match predefined taxi routes from the TaxlineConfig table in the airport apron operation database using the three-dimensional keywords: "starting gate number + target destination type (handover point / takeoff runway) + aircraft type (C / D / E / F category)". The target destination type must clearly distinguish between apron control handover points (e.g., J2 handover point, G1 handover point) and takeoff runways (e.g., runway 36R, runway 05L). If a unique matching route exists, that route (including sub-segment sequence, key node passage order, prohibited turning nodes, etc.) is directly used as the aircraft's taxi path. If multiple matching routes exist, the optimal route with the shortest total sub-segment length and the fewest key nodes is selected.

[0050] The second step is to plan the shortest gliding path based on the constrained Dijkstra algorithm when there is no matching predefined route.

[0051] When no predefined matching route is available, Dijkstra's algorithm, incorporating apron operation constraints, is used. With "minimizing the total physical length of sub-segments" as the sole objective function, the algorithm combines a topology model with apron-specific constraints to plan the shortest taxiing path. The specific planning process is as follows: (1) Graph model parameterization and constraint preprocessing Based on the "node-segment" topology model of airport taxiway paths, the parameterization definition and pre-constraint filtering of the graph model are completed: Key nodes and virtual nodes in the topology model are uniformly treated as vertices of the graph. Each vertex is assigned a unique identifier (such as Node J201, Node X002) and associated with attributes such as the vertex's spatial coordinates and node type (normal / special). The sub-segments in the topology model are used as directed edges connecting vertices. Each directed edge is assigned a unique identifier (e.g., Edge J201-J202) and bound to the following core attributes: the weight of the edge is the actual physical length of the sub-segment (unit: meters, which is the sole basis for path length calculation), the type of aircraft the sub-segment is adapted to (e.g., C / D class, E / F class), and the direction of travel of the sub-segment (one-way / two-way). Constraint pre-filtering: Based on the current aircraft type, parking position pushback direction, and real-time towing task status, infeasible directed edges in the graph model are marked as "forbidden access". Specifically, this includes: edges whose sub-segment's compatible aircraft type does not match the current aircraft type, unidirectional edges opposite to the parking position's specified pushback direction, and edges currently occupied by towing tasks and not yet released. Forbidden access edges are not included in subsequent path planning.

[0052] (2) Dijkstra's algorithm initialization Set the starting vertex: the taxiway access vertex corresponding to the current aircraft's parking position (i.e., the first vertex the aircraft enters the taxiway after pushback). Set target vertex: Connect the vertex to the taxiway corresponding to the current aircraft's destination (target handover point / takeoff runway); Initialize vertex attributes: Assign "shortest path weight" and "predecessor vertex identifier" to all vertices in the graph. The shortest path weight of the starting vertex is initialized to 0, and the shortest path weight of all other vertices is initialized to infinity. The predecessor vertex identifier of all vertices is initialized to empty, and all vertices are marked as "unvisited".

[0053] (3) Unvisited vertex traversal and shortest path weight update Step 1: Select the vertex with the smallest shortest path weight from all "unvisited" vertices as the current vertex. If the current vertex is the target vertex, terminate the traversal directly. Step 2: Traverse all adjacent directed edges of the current vertex that are not prohibited from being accessed, and find the adjacent vertex corresponding to each edge; Step 3, calculate candidate weight values: candidate weight value = shortest path weight value of the current vertex + physical length weight of the corresponding adjacent directed edge; Step 4: If the candidate weight value is less than the current shortest path weight value of the adjacent vertex, then update the shortest path weight value of the adjacent vertex to the candidate weight value, and update the predecessor vertex identifier of the adjacent vertex to the current vertex; if the candidate weight value is greater than or equal to the current shortest path weight value of the adjacent vertex, keep the attributes of the adjacent vertex unchanged. Step 5: Mark the current vertex as "visited", return to the above steps to continue traversing until all vertices have been visited or the target vertex has been reached.

[0054] (4) Shortest path determination and path backtracking If the shortest path weight of the target vertex is still infinite, it is determined that "there is no feasible glide path" and a manual control warning is immediately triggered; if the shortest path weight of the target vertex is a finite value, starting from the target vertex, backtracking is performed in reverse according to the "predecessor vertex identifier" of each vertex until the starting vertex. The vertex sequence obtained by backtracking is sorted in the forward direction of the glide. The directed edges between the vertices form the initial shortest glide path, which is a feasible path with the "minimum total physical length of the sub-segments".

[0055] (5) Path constraint secondary verification The initial shortest taxiway path is verified a second time to confirm whether there are any temporary infeasible constraints in the path (such as sudden runway warning position occupancy or temporary aircraft position construction). If there are, the corresponding sub-segment is marked as prohibited from access, and the above steps (1)-(4) are repeated. If the verification passes, the initial shortest taxiway path is the final planned shortest taxiway path.

[0056] The third step is to make local adjustments to the above-mentioned planned route: If there are situations where the time window of the route overlaps with that of the taxiing aircraft or the key nodes are occupied for a long time (occupancy time > 5 minutes), adjustments are made by means of "sub-segment replacement" (selecting adjacent parallel sub-segments) or "node detour" (adding 1-2 key nodes to avoid conflict areas), to ensure that the increase in the length of the adjusted route does not exceed the set proportion of the original route, such as 10%.

[0057] The configured taxiing speed is dynamically adjusted according to the scenario: the default speed for straight sections is 20km / h (equivalent to 5.56m / s), and the speed for curved sections (curve apex angle ≤90°) is reduced to 15km / h (4.17m / s). For E / F category large aircraft, the speed for all sections is adjusted to 80% of the default speed (16km / h = 4.44m / s for straight sections and 12km / h = 3.33m / s for curved sections). In special operating conditions such as rain and snow, the speed is adjusted to 70% of the default speed (real-time operating condition data needs to be obtained from the airport meteorological system).

[0058] The critical nodes are set by time classification: ordinary critical nodes (physical intersections, curve apex) are set to 30 seconds by default, special critical nodes (runway warning positions, intermediate holding positions) are set to 60 seconds by default, and can be shortened to 30 seconds when no other aircraft are occupying them.

[0059] The safety interval buffer time is configured differently: 60 seconds for taxiing in the same direction, 90 seconds for taxiing in opposite directions, and 120 seconds for sub-sections in the harbor area.

[0060] The time window is calculated recursively according to the following logic: The actual taxiing start time (Tstart) is taken as "the aircraft's estimated pushback time in the evaluation sequence + 60 seconds of pushback preparation time," and calculated sequentially according to the order of sub-segments and key nodes in the taxiing path. For each sub-segment (numbered Edge1, Edge2, ..., Edgem according to taxiing order), its occupancy start time is: for the first sub-segment, Tstart is used; for subsequent sub-segments, the occupancy end time is used, where occupancy end time = sub-segment occupancy start time + (sub-segment length / corresponding taxiing speed) + safety interval buffer time. For each key node (numbered Node1, Node2, ..., Noden according to passage order), its occupancy start time = the occupancy end time of the previous sub-segment, where occupancy end time = key node occupancy start time + corresponding node passage time + safety interval buffer time. This ultimately forms a structured time window data of "sub-segment / node number - occupancy start time - occupancy end time," used for subsequent conflict detection.

[0061] S2202, after being calculated by S2201, check whether there is spatiotemporal overlap in the path resource occupancy time windows of all aircraft in the sequence to be evaluated, and calculate the total pushback waiting time corresponding to the sequence to be evaluated.

[0062] The presence of spatiotemporal overlap is a key focus of the verification, which includes three types of scenarios: crossover conflict, head-on conflict, and tail-end conflict. If no conflict exists, the sequence is determined to "satisfy the constraints"; otherwise, it is determined to "not satisfy the constraints". For candidate sequences that "satisfy the constraints", the total pushback waiting time is calculated according to the following rule: Total pushback waiting time = Σ[(Tpush)] i -Tready i )×ω i ], where ω i The release status weighting factor for the i-th scheduled departing aircraft (the aircraft ω in the CLD status has been granted release clearance). i =1.5, aircraft not released ω i =1.0); for candidate sequences that “do not meet the constraints”, the objective function value is not calculated and they are directly marked as discarded.

[0063] S2203, Iterative Search: Using the optimal sequence of the current iteration as the current solution sequence, the following steps are executed in each iteration: (1) Transformation operation: Based on the current solution sequence, a new candidate exit sequence is generated through heuristic rules. Transformation methods include but are not limited to: ① Adjacent exchange: Randomly select two adjacent planned departing aircraft in the sequence and exchange their order; ② Insertion shift: Randomly select a planned departing aircraft in the sequence and insert it into another non-conflicting position in the sequence; ③ Segment reversal: Select multiple consecutive aircraft in the sequence, such as 2-3 aircraft, to form a segment and reverse their order. (2) Candidate evaluation: Take the new candidate sequence generated in step (1) as the sequence to be evaluated, and repeat S2201 and S2202 to complete the constraint verification and objective function value calculation; (3) Solution update: Based on the evaluation results of step (2), the following acceptance criteria are used to decide whether to update the solution: ① If the new candidate sequence meets the constraints and its total launch waiting time is less than the objective function value of the current solution sequence, then the new candidate sequence is directly updated to the current solution sequence for the next iteration; ② If the new candidate sequence meets the constraints and its total launch waiting time is slightly higher than the current solution sequence, but the cumulative waiting time reduction of released aircraft is greater than or equal to a preset multiple of the total waiting time increase, such as 1.2 times, then it is still updated to the current solution sequence; ③ If the new candidate sequence does not meet the constraints or does not meet any of the above acceptance criteria, then the candidate sequence is discarded and the current solution sequence is retained for the next iteration.

[0064] S230, from all evaluated candidate sequences, select the candidate sequence with the minimum total launch waiting time that satisfies the constraints, as the initial launch sorting sequence.

[0065] From all the evaluated candidate sequences that meet the constraints, select the sequence with the smallest overall launch waiting time as the initial launch sorting sequence output; if multiple sequences have the same objective function value, select the sequence with the smallest average waiting time of released flights.

[0066] The preliminary rollout sequence includes at least the following information: flight number, parking position, estimated rollout time, taxiway details, time window for occupying key resources for each departing aircraft, and constraints imposed on its order by arriving aircraft and towing tasks.

[0067] S300, the preliminary launch sorting sequence is sent to the three-dimensional visual simulation system so that the three-dimensional visual simulation system can plan taxiing paths for each aircraft based on the expected launch time and perform conflict detection on the taxiing paths of all aircraft within a preset future time period.

[0068] The 3D visual simulation system used in this invention is a civil aviation-specific 3D visual simulation system adapted to the needs of airport apron control. It can be implemented by customizing the existing mature apron 3D visual simulation system of the airport, or by secondary development using a commercial 3D visual simulation system that conforms to civil aviation industry standards. The system achieves real-time data exchange with the airport's existing air traffic control tower automation system, airport information integration system, and flight operation database. It has five core functional modules: data interaction, topology model management, path planning, fine-grained conflict detection, and 3D visualization. It has also been specially adapted for the pre-sorting requirements of this solution: 1) 1) Implant the airport taxiway path "node-segment" topology model that is completely consistent with S2201 to ensure the unified definition of topology resources for path planning, conflict detection and preliminary sorting; 2) Develop a dedicated data interface with the apron control pre-sorting main system to support the batch reception of preliminary sorting sequences and real-time feedback of path planning results and conflict detection reports; 3) Customize and develop a fine-grained conflict detection module based on time windows to adapt to the resource occupation conflict detection needs of multiple scenarios such as apron arrival, departure and towing tasks; 4) Support the three-dimensional visualization marking and trajectory simulation of planned paths, conflict areas and conflicting aircraft to facilitate the intuitive viewing of verification results by air traffic controllers.

[0069] The 3D visual simulation system pre-configures and updates a complete topology model of the organic scene taxiing path in real time. This topology model is consistent with the topology model used for taxiing path planning in S2201, ensuring resource consistency for the entire path planning and conflict detection process. Its core construction rules based on the node-segment model are as follows: Key node definition: Physical intersections of aprons and taxiways, runway warning positions, intermediate holding positions, curve apex, aircraft stand access points, and control handover points are uniformly defined as key nodes. Each key node is assigned a unique identifier and three-dimensional spatial coordinates, associated with node type (normal / special), access permissions, and other attributes, and is visually marked in the three-dimensional view. Segment and Sub-segment Definition: A continuous taxiway segment between two adjacent key nodes is defined as a basic segment. The basic segment is associated with core attributes such as length, width, and compatible aircraft type. If the length of a basic segment exceeds a preset threshold (default 200 meters, which can be adjusted according to the actual airport scenario), virtual nodes are inserted on the segment at preset intervals (default 50 meters) to divide it into multiple equal sub-segments (taxiway micro-segments). Virtual nodes are only used for path subdivision and time window calculation and are not used as passage nodes on their own. Topology model adaptation: The 3D visual simulation system will synchronize the resource status data (such as sub-segment occupancy, node failure, etc.) of the airport operation database in real time, and dynamically update the resource availability in the topology model to ensure that the model is consistent with the actual operating status of the apron.

[0070] After receiving the initial sorting sequence, the 3D visual simulation system simultaneously initiates the gliding path planning and collision detection process. The gliding path planning, as a prerequisite for collision detection, specifically performs the following extended steps: S301, Predefined Fixed Taxi Route Query and Matching: The 3D visual simulation system connects to the TaxlineConfig table of the airport apron operation database through an interface. For each aircraft in the initially released sorting sequence, it queries whether there is a matching predefined fixed taxi route by using the three-dimensional keywords "starting gate number + target destination type (handover point / takeoff runway) + aircraft type (C / D / E / F category)". During the query process, the system simultaneously verifies the current availability of the predefined route (e.g., whether sub-segments in the route are occupied by towing tasks, whether they meet the current aircraft type restrictions). If there is a unique matching and available predefined fixed taxi route, the route is directly adopted as the planned path for the current aircraft, and the path information (sub-segment sequence, key node passage order) is bound to the 3D visual scene to generate a visual taxi trajectory. If there are multiple matching routes, the optimal route with the shortest total sub-segment length, the fewest key nodes, and no temporary occupation is selected. S302, Shortest Path Automatic Planning (When No Predefined Route is Found): If no matching predefined fixed taxiing route is found, the 3D visual simulation system will automatically call the shortest path algorithm (based on the constrained Dijkstra algorithm described in detail in S2201, the algorithm steps will not be repeated here). With "minimum total physical length of sub-segments" as the objective function, relying on the system's internal topology model, key nodes and virtual nodes are used as vertices of the graph, and sub-segments are used as edges between vertices with a weight equal to the physical length (unit: meters). The system automatically incorporates apron-specific constraints such as aircraft type restrictions for sub-segments, parking position pushback direction constraints, and avoidance of towing tasks occupying road sections, to build a graph model adapted to the current aircraft and quickly plan a feasible shortest taxiing path. After the planning is completed, the system will perform a preliminary verification of the path. After confirming that there are no unusable resources, it will generate a detailed path and a 3D visualized trajectory. S303, Taxiing Estimated Time Calculation: After path planning is completed, the 3D visual simulation system will automatically match the corresponding taxiing speed parameters based on the current aircraft type, the type of taxiing path segment (straight / curved), and the airport's real-time weather conditions (briefly connecting to the scenario-based speed rules mentioned earlier: straight sub-segments default to 20km / h, curved sub-segments are reduced to 15km / h, E / F category large aircraft are adjusted to 80% of the default speed, and special conditions such as rain and snow are adjusted to 70%). Combining the total length of the planned path and the transit time of each key node, the system calculates the estimated total time for the current aircraft to taxi along the path, and also estimates the estimated time for the aircraft to arrive at each key node, handover point, and destination, providing the core time dimension basis for subsequent conflict detection.

[0071] Once path planning is complete, the 3D visual simulation system immediately initiates a full-scene conflict detection process for the preset future time period (this is an extended core, supplementing the missing detection details of the original content). The specific detection logic is as follows: Detection Scope and Time Window: The detection scope covers the planned taxiing paths of all aircraft in the initial sorting sequence, as well as the taxiing trajectories of all aircraft that are already taxiing or about to taxi within a preset future time period (default 30 minutes, consistent with the time window of the aircraft to be sorted) (including aircraft that are scheduled to arrive, depart, or are involved in towing missions). Detection content and types: Based on the resource allocation of the topology model, the focus is on detecting three types of core conflicts (consistent with claim 8), all based on the core principle of "non-overlapping resource occupation time windows," and accurately verified by combining the spatial visualization characteristics of the 3D view. (1) Handover point conflict detection: Detect whether the estimated transit times of different aircraft at the same control handover point overlap. If they overlap and no sufficient safety interval is reserved (default 90 seconds), it is marked as a handover point conflict, and the conflict handover point identifier, conflicting aircraft and conflict time period are recorded. (2) Taxi path conflict detection: Detect whether the time windows occupied by different aircraft on the shared taxiway (basic section / sub-section) overlap. Focus on verifying three types of scenarios: cross conflict, head-on conflict, and tail-end conflict. If there is overlap, it is marked as a path conflict. Clarify the conflict section, conflict type and conflict duration. (3) Detection of aircraft stand operation conflicts: Detect whether there is a conflict between the pushback time and the entry time of the aircraft between adjacent aircraft stands or aircraft stands with operational constraints (e.g., when an aircraft pushes out at a certain aircraft stand, an aircraft at a neighboring aircraft stand is entering the stand and occupying the shared access road). If there is a conflict, it is marked as an aircraft stand operation conflict. Conflict severity classification and result recording: The 3D visual simulation system classifies detected conflicts into "severe conflicts" (such as head-on taxiing conflicts and unavoidable path conflicts) and "general conflicts" (such as handover point conflicts that can be avoided by adjusting the pushback time) based on the severity of the conflict, and generates a detailed conflict detection report. The report includes the conflicting aircraft identification, conflict type, conflict resources, conflict time period, conflict level, and preliminary avoidance suggestions. Feedback on detection results: The 3D visual simulation system synchronously feeds back the path planning results (planned paths and estimated time for each aircraft) and conflict detection reports (details of all conflicts) to the apron control pre-sequencing main system, providing accurate data support for S400 to adjust the initial sorting sequence based on the conflict detection results; at the same time, the system will visually mark the planned paths, conflict areas and conflicting aircraft in the 3D visual interface, making it easy for controllers to view intuitively.

[0072] S400, receive the conflict detection result from the three-dimensional visual simulation system. If the conflict detection result indicates that there is a path conflict, adjust the preliminary exit sorting sequence based on the conflict detection result to generate a conflict-free target exit sorting sequence.

[0073] The S400 process specifically includes the following steps: S401, receiving and parsing collision detection results.

[0074] Data Reception and Verification: The apron control pre-sorting main system receives all conflict detection-related data in batches through a dedicated data interface with the 3D visual simulation system, and simultaneously verifies the completeness and accuracy of the data (such as verifying whether the conflicting aircraft identifiers are in the set to be sorted, whether the conflicting resource identifiers match the topology model, and whether the time window data is reasonable). If there is any missing or abnormal data, a retransmission request is immediately sent to the 3D visual simulation system to ensure that subsequent adjustments are based on complete and accurate data.

[0075] Conflict Detection Result Analysis: The pre-sorting main system parses the format and extracts core information from the verified conflict detection data. First, it converts the raw data (including structured reports and non-standardized fields) pushed by the 3D visual simulation system into a unified data format that matches the database of the pre-sorting main system. Then, it extracts all core fields of the conflict from the parsed data, including but not limited to the unique identifier of the conflicting aircraft, conflict type, conflict resource number, conflict start / end time, conflict level, 3D visual association identifier, and preliminary avoidance suggestions. At the same time, it performs field standardization verification on the extracted information to ensure that there are no field misalignments or information distortions, laying a data foundation for subsequent conflict classification and analysis.

[0076] Conflict Classification and Prioritization: The pre-sorting main system performs hierarchical classification processing on the parsed conflict detection results. Combining the conflict level (severe conflict / general conflict), the scope of conflict impact (single aircraft conflict / multi-aircraft chain conflict), and the duration of conflict, it prioritizes all conflicts. The ranking rule is: severe conflict (such as head-on taxiing, unavoidable path intersection) > multi-aircraft chain conflict > general conflict (such as overlapping handover point times). Under the same priority, the longer the conflict duration and the more aircraft affected, the higher the priority.

[0077] Conflict Correlation Analysis: The pre-sorting main system automatically analyzes the correlation between conflicts to determine whether there are related scenarios such as "the same aircraft causing multiple conflicts" or "adjusting a certain conflict will lead to new conflicts." For example, if the pushback time of a scheduled departing aircraft is unreasonable, it will cause both handover point conflicts and path conflicts. The pushback time of this aircraft should be adjusted first to resolve multiple related conflicts simultaneously. If adjusting the sorting position of an aircraft will cause it to have new path conflicts with other aircraft, it is necessary to predict this in advance and formulate alternative adjustment plans.

[0078] S402, Conflict Detection and Layered Processing Logic.

[0079] The apron control pre-sequencing main system, based on conflict resolution results, handles two core scenarios to ensure that the processing logic aligns with the actual needs of apron control, while maximizing the optimality of the initial S200 sorting sequence (minimizing overall rollout waiting time). Scenario 1: The collision detection result indicates "no collision" or "only negligible minor collision exists" (e.g., safety interval gap ≤ 30 seconds, and does not affect apron operation safety): The pre-sorting main system directly determines the preliminary push-out sorting sequence generated by S200 as the target push-out sorting sequence, and synchronously records the basis for the no-collision judgment, without any adjustment. Scenario 2: Conflict detection results indicate "conflicts requiring adjustment exist" (including severe and general conflicts): The pre-sorting main system initiates the sequence adjustment process, following the core principles of "prioritizing the avoidance of severe conflicts, minimizing the adjustment range, and taking into account operational efficiency." Based on conflict priority and correlation, it adopts a closed-loop logic of "layered adjustment, conflict elimination step by step, and post-adjustment verification," employing different adjustment strategies to gradually eliminate all conflicts. The specific adjustment strategies and processes are as follows.

[0080] The sequence adjustment aims to "eliminate all conflicts and retain as much of the optimization results of the original initial sequence as possible (minimizing the overall rollout waiting time)." Combining conflict type and priority, it employs a closed-loop process of "layered adjustment, conflict-by-conflict elimination, and post-adjustment verification," specifically divided into three levels: (a) Level 1 Adjustment: Emergency adjustments for serious conflicts (priority handling) Severe conflicts (head-on taxiing conflicts, path crossing conflicts that cannot be avoided by time adjustments, and severe conflicts involving multiple aircraft) directly threaten apron operational safety and must be eliminated by prioritizing "significant adjustments + path coordination." Specific adjustment methods include: Core adjustment measures: Prioritize adjusting the order of conflicting aircraft (e.g., postponing their order to avoid conflict periods). If order adjustment cannot avoid conflict (e.g., if the conflict involves multiple aircraft and order adjustment would trigger new chain conflicts), then simultaneously link the 3D visual simulation system to fine-tune the planned taxiing paths of 1-2 conflicting aircraft (e.g., replacing them with adjacent parallel sub-segments or adding 1-2 key nodes for detours), ensuring that the increase in path length after adjustment does not exceed 10% of the original path (to avoid increased taxiing time and triggering new conflicts due to excessively long paths). Auxiliary adjustment measures: If sorting order and minor path adjustments still cannot avoid severe conflicts, the estimated pushback time of the conflicting aircraft can be slightly adjusted (the adjustment range should be controlled within 30-60 seconds), but it must meet the requirement that "the adjusted pushback time ≤ the latest pushback time calculated by CTOT backwards" (i.e., Tpush). i ≤CTOT-Ttax i (out) to avoid affecting the normal takeoff of flights; Adjustment example: If there is a serious head-on taxiing conflict between aircraft A and aircraft B (sharing a certain bidirectional sub-segment, with completely overlapping time windows), the pre-sorting main system will first shift the sorting position of aircraft B two positions backward, and simultaneously check whether the time window of aircraft B after the adjustment conflicts with other aircraft; if there is still a conflict, the system will link up with the three-dimensional visual simulation system to adjust the taxiing path of aircraft B to an adjacent parallel sub-segment to ensure that the path resources occupied by the two do not overlap.

[0081] (ii) Secondary adjustment: fine-tuning of general conflicts (minor handling) General conflicts (overlapping handover times, minor rear-end collisions, and avoidable gate operation conflicts) do not directly threaten safety. Therefore, the "minimum adjustment" should be prioritized to maximize the preservation of the optimal total waiting time of the original preliminary sequence. Specific adjustment methods are as follows: Priority adjustment method: Only make minor adjustments to the estimated pushback time of the conflicting aircraft, with the adjustment range controlled within 10-30 seconds, without adjusting the sorting order and taxiing path; for example: if aircraft C and aircraft D have time overlap at a certain handover point (the interval is only 60 seconds, which does not reach the 90-second safe interval), the pre-sorting main system will delay the estimated pushback time of aircraft D by 30 seconds and simultaneously calculate its new time window to ensure that the safe interval between the two at the handover point is ≥90 seconds; Alternative adjustment methods: If time fine-tuning cannot avoid general conflicts (such as excessive safety gap gaps), the "adjacent position swap" method will be adopted to adjust the order of conflicting aircraft and adjacent non-conflicting aircraft, and update their estimated pushback times synchronously to ensure that while eliminating conflicts, the total pushback waiting time increment does not exceed 5% of the initial pushback order sequence generated by S200; Constraints and controls: All adjustments to general conflicts must meet the requirement that "the waiting time of a single aircraft after adjustment shall not exceed 1.2 times the original waiting time" to avoid affecting apron turnaround efficiency due to excessively long waiting times for a single aircraft.

[0082] (III) Level 3 Adjustment: Coordinated Adjustment of Chain Conflicts (Supplementary Handling) If multiple related conflicts exist (e.g., adjusting a certain aircraft triggers two or more new conflicts), the pre-sorting main system will initiate a collaborative adjustment mode. The specific process is as follows: Conflict correlation modeling: Integrate all related conflict aircraft, conflict resources, and time windows to construct a "conflict correlation model" and clarify the causal relationship between each conflict (e.g., adjusting aircraft E leads to a new conflict between aircraft F and aircraft G). Global Coordinated Adjustment: Based on the correlation model, the "multi-aircraft synchronous fine-tuning" method is adopted to comprehensively adjust the sorting position and pushback time, prioritizing to ensure that the waiting time of released aircraft (CLD status) does not increase, while eliminating all chain conflicts; for example, adjusting the pushback time of aircraft E by 20 seconds, simultaneously advancing the pushback time of aircraft F by 10 seconds and shifting the sorting position of aircraft G by 1 position, to achieve multi-aircraft coordinated collision avoidance; Adjustment range control: The overall adjustment range of the chain conflict must ensure that the overall launch waiting time of the target sequence after adjustment does not exceed 10% of the overall waiting time of the original initial sequence, so as to avoid destroying the optimization objective of S200.

[0083] After all conflict adjustments are completed, the pre-sorting main system initiates a "double verification" process to ensure that the target sequence is conflict-free and adapts to the apron operation requirements: First verification (automatic verification): The pre-sorting main system will send the adjusted preliminary sorting sequence to the 3D visual simulation system again to trigger a secondary conflict detection. The key verification is whether the adjusted sequence has eliminated all conflicts and whether new conflicts have been generated. If conflicts still exist, the system will return to the corresponding adjustment level and readjust until there are no conflicts. The second verification (constraint compliance verification): The pre-sorting main system automatically verifies whether the adjusted target sequence meets all apron operation constraints and optimization objectives, specifically including: whether the arrival priority constraint is met, whether the pushback time of all planned departure aircraft is ≤ the latest pushback time, whether the overall pushback waiting time is controlled within a reasonable range of "not exceeding 10% of the total waiting time of the original preliminary sequence", and whether the path adjustment range meets the requirements; Target sequence determination: If both checks pass, the pre-sorting main system will officially determine the adjusted sequence as the "conflict-free target exit sorting sequence", and simultaneously record the adjustment process (including original conflict details, adjustment strategy, adjustment range, and check results) to form a complete adjustment log for easy subsequent traceability and maintenance; if the check fails, the pre-sorting main system will return to the conflict resolution stage to re-analyze the conflict and optimize the adjustment plan.

[0084] In addition, if a "serious conflict cannot be avoided through sequence adjustment and path fine-tuning" occurs (such as large-scale construction on the apron or closure of multiple core taxiways), the pre-sequencing main system will immediately trigger an early warning mechanism, simultaneously pushing the conflict details and early warning information to the electronic progress sheet interface and 3D visual simulation system at the apron control position, and issuing audible and visual warning prompts, allowing controllers to make manual intervention adjustments. At the same time, the pre-sequencing main system will mark the conflicting aircraft in the initial sequence as "awaiting manual adjustment," while the remaining non-conflicting aircraft will proceed according to their original sequence, and simultaneously record the manual intervention early warning log to ensure uninterrupted apron operations and traceability of the adjustment process.

[0085] S500, the target output sorting sequence is output to the display interface and visualized as a reference for control instructions.

[0086] In this invention, the apron control pre-sequencing main system generates a sequence of conflict-free targets determined by S400, simultaneously completing dual output and visualization. On one hand, the output is shown to the apron controller's core operating interface as a reference for control instructions for review and confirmation. On the other hand, it is simultaneously pushed to a 3D visual simulation system, achieving a linked display of the "operating interface + 3D situation" dual interfaces, ensuring that controllers can intuitively grasp the sequencing information, potential risks, and future aircraft operational status. The apron control pre-sequencing main system is a modular software system deployed on a dedicated server in the airport apron control center, serving as the core hardware / software carrier for executing the pre-sequencing method described in this application.

[0087] The display interface is the electronic progress sheet interface for the apron control position. This interface is the core operating interface of the air traffic control tower automation system, and it achieves real-time data linkage with the apron control pre-sequencing main system, the 3D visual simulation system, and the flight operation database. It is the core basis for apron controllers to issue pushback control instructions. The target pushback sequence is displayed in this interface using a dual-mode visualization method of "list + timeline," which can be manually switched by the controller. Specific display details are as follows: List mode display (default display mode): Presents complete information on the target departure sequence in a structured list format. Each list entry corresponds to a planned departing aircraft. The entry includes the following core fields (consistent with the sequence fields of S200 and S400 to ensure data consistency): unique aircraft identifier (flight number + aircraft number), aircraft type, starting gate number, destination (target handover point / departure runway), estimated departure time, adjusted waiting time, and sequence position. The sorting status of each entry is also marked (unconfirmed / confirmed / adjusted). The list is sorted in ascending order by sorting position, making it easy for controllers to quickly view the departure order.

[0088] Timeline mode display (optional mode): A visual timeline is constructed with time as the horizontal axis and aircraft as the vertical axis. The estimated pushback time of each aircraft is used as the core time node, and the corresponding aircraft identification, starting position and taxiway abbreviation are marked at the node. At the same time, the estimated taxiing time of the aircraft is marked with different colored line segments, and the length of the line segment corresponds to the estimated taxiing time (echoing the taxiing time calculation results of S300), which makes it easier for controllers to intuitively judge the time window distribution of different aircraft and avoid temporary conflicts.

[0089] To ensure controller flexibility and simultaneously meet the dynamic adjustment needs of apron operations, the electronic progress sheet interface provides controllers with a complete interactive interface, equipped with three core interactive controls: "One-click acceptance sorting," "Manual order adjustment," and "View conflict details." The specific functions and operating logic of each control are as follows, ensuring that those skilled in the art can reproduce the interaction process based on the description: One-click acceptance sorting: After the controller confirms that there are no objections to the target launch sorting sequence, they can click this control. The system will automatically mark the current sorting sequence as "confirmed", simultaneously push the sequence information to the flight operation database for archiving, and trigger the subsequent control instruction issuance process (such as synchronizing the estimated launch time to the pushcart dispatching system). After clicking, the control status changes to "accepted" and cannot be clicked repeatedly. If modification is required, "cancel acceptance" must be clicked first (a matching cancellation control is added to improve the interaction logic).

[0090] Manual Order Adjustment: For temporary apron operational needs (such as sudden support delays or controller preferences), controllers can adjust the order of aircraft using this control. The specific operation logic is as follows: Select an aircraft entry in the list / timeline, click the "Move Up" or "Move Down" sub-controls to adjust its order, or drag the entry directly to the target position. During the adjustment process, the system automatically verifies in real time whether new spatiotemporal conflicts are generated after the adjustment (calling the core conflict detection logic of S300 to simplify the verification process). If a conflict occurs, a pop-up window will immediately prompt the conflict type, conflict resources, and adjustment suggestions, and the adjustment results cannot be saved. After the adjustment is completed, the system automatically updates the estimated pushback time and waiting time of the aircraft and related aircraft, synchronously updates the content displayed in the list and timeline, and records the adjustment log (connected with the adjustment log of S400 for easy traceability).

[0091] View Conflict Details: Click this control (which can be linked to a specific aircraft entry or viewed globally). The system will automatically pop up a conflict details window, which displays complete information on all potential conflicts in the target rollout sequence (potential conflicts refer to temporary conflicts, minor safety gaps, or conflicts that may occur during subsequent dynamic operations that may still exist after S400 double verification). Specifically, it includes the conflicting aircraft identification, conflict type (consistent with S300 conflict detection types: handover point conflict / path conflict / stand operation conflict), conflict resource number, expected conflict period, safety gap, and preliminary avoidance recommendations. The information is fully synchronized with the S300 conflict detection report and S400 adjustment records, facilitating rapid assessment by controllers.

[0092] In addition, the electronic progress sheet interface uses a visual approach to highlight potential conflicts between any two flights in the target launch sequence. The specific highlighting rules are as follows: for aircraft entries with potential conflicts, the entries are marked with a red border in list mode, and conflict-related fields (such as estimated launch time) within the entries are highlighted in red; in timeline mode, the time segments of the corresponding aircraft are marked in red, and exclamation mark icons are added at the conflict time nodes; at the same time, a conflict warning bar is set at the top of the interface, which displays the number of potential conflicts and the highest conflict level in real time. Clicking the warning bar will quickly jump to the corresponding conflict details window, ensuring that controllers can promptly detect and handle potential risks.

[0093] To further enhance controllers' situational awareness, the apron control pre-sequencing main system removes targets from the sorting sequence and synchronously pushes them to the 3D visual simulation system via a dedicated data interface. This results in a linked and visualized display on the 3D situational awareness interface. The displayed content maintains data consistency with the electronic progress sheet interface and is mapped 1:1 to the actual apron scenario (based on the S300 topology model), as detailed below: Core display content: In the 3D situational awareness interface, key information of all planned departing aircraft in the target launch sequence is displayed simultaneously, including at least: unique aircraft identifier (flight number + aircraft number, bound to the aircraft 3D model as a floating tag), estimated launch time (displayed synchronously by the floating tag), corresponding future taxiing path (based on the S300 path planning results, marked with a blue solid line in the 3D topology model, with the path width adapted to the aircraft type), and estimated arrival time at each key node / handover point (time markers are added at the corresponding nodes).

[0094] Differentiated display rules: To facilitate controllers in distinguishing different aircraft, different colors are assigned to the 3D models of aircraft according to their type category (C / D / E / F) (e.g., blue for C / D, orange for E / F); the taxiway of confirmed aircraft is marked with a solid green line, while that of unconfirmed aircraft is marked with a dashed blue line; for aircraft with potential conflicts, a red flashing effect is added to their 3D models, and the corresponding conflict path segments are marked with solid red lines, with conflict nodes and conflict periods also indicated.

[0095] Interactive linkage function: The 3D situational awareness interface of the 3D visual simulation system is linked with the electronic progress sheet interface. When the controller selects an aircraft entry in the electronic progress sheet interface, the 3D situational awareness interface automatically locates the aircraft's starting position and highlights its 3D model and taxi path. Clicking on the floating tag of an aircraft in the 3D situational awareness interface can quickly jump to the corresponding entry in the electronic progress sheet interface, which is convenient for controllers to view and operate across interfaces and improve control efficiency.

[0096] After the target pushback sequence is displayed on both interfaces, it awaits approval from the apron controller. If the controller confirms the sequence using the "One-Click Adoption Sequence" control on the electronic progress sheet interface, the 3D visual simulation system automatically uses this sequence as the final control instruction reference and simultaneously issues it to the pushback dispatch system and the flight ground support system to guide on-site support and pushback operations. If the controller adjusts the sequence using the "Manually Adjust Sequence" control, the adjusted sequence is automatically synchronized to the 3D visual simulation system, updating the content displayed on both interfaces and re-triggering a simple conflict check. Once the check passes, it can be confirmed as effective. If the controller discovers a major potential conflict, they can use the "View Conflict Details" control to assess the situation and then return to S400 to restart the sequence adjustment process, ensuring that the final output control instruction reference is safe and feasible.

[0097] Furthermore, considering the unique operational characteristics of U-shaped harbor parking positions (U-shaped harbor parking positions typically have multiple positions sharing a single entrance / exit; the critical node at the harbor entrance is the only necessary passage for all aircraft to push back and enter, and the passage space is narrow, making two-way passage impossible and prone to pushback and entry conflicts), when planning pushback paths for aircraft located at U-shaped harbor parking positions, if the planned path needs to occupy a critical node at the harbor entrance, the 3D visual simulation system executes the following rules during path planning, conflict detection, and sequencing adaptation: The key nodes at the harbor entrance are identified as key resources with exclusive use attributes; When allocating a time window for the resource to an aircraft, if the resource is already occupied within the preset future time period, subsequent allocated time windows must not overlap with the already allocated time windows, and priority should be given to ensuring the right to occupy the resource for aircraft already in the pushback process. Specifically: Precise definition and marking of key nodes at the harbor entrance: First, the specific scope of the key node at the harbor entrance corresponding to the U-shaped harbor stand is clearly defined. This key node specifically refers to the only intersection of the taxiing area inside the U-shaped harbor stand and the main taxiway of the apron. It is also the necessary node for all aircraft (including those scheduled to push back or depart, and those scheduled to enter or leave the harbor) to enter or leave the harbor. Based on the topology model, the 3D visual simulation system assigns a unique identifier to this type of node (such as Node_Harbor_U01, with the suffix distinguishing different U-shaped harbor stands) and marks its "exclusive resource" attribute to distinguish it from ordinary key nodes (such as main taxiway intersections). At the same time, it associates the corresponding U-shaped harbor stand number and the list of stands included in the harbor, which facilitates the system's accurate identification of the associated aircraft at this node.

[0098] The rules for occupying exclusive resources are refined: The 3D visual simulation system regards the key node at the entrance of the harbor as a core resource that "only one aircraft is allowed to use exclusively at the same time." Its occupation time window covers the entire time period from "entering the node to completely exiting the node." The specific calculation rules are as follows: Occupation start time = estimated time for the aircraft to arrive at the entrance of the node; Occupation end time = estimated time for the aircraft to completely exit the exit of the node + 30-second safety buffer time (adapting to the characteristics of narrow U-shaped harbor parking spaces and inconvenient turning, reserving sufficient space for avoidance); Among them, the estimated time to exit the node = node length / aircraft's suitable taxiing speed (the default length of the node at the entrance of the U-shaped harbor is calculated as 50 meters, and the taxiing speed is reduced to 15 km / h, which is lower than the default speed of the main taxiway).

[0099] Priority Logic Execution (Connecting Conflict Detection and Sequencing Adaptation): When performing conflict detection and sequencing adaptation, the 3D visual simulation system strictly adheres to the principle that "aircraft already in the pushback process have priority in occupying this node." The specific execution logic is divided into two steps to ensure that priority is feasible and verifiable: (1) Priority determination criteria: Clarify the conditions for determining "aircraft that are already in the pushback process". Based on whether the aircraft has completed the three operations of "trolley connection, wheel chock removal, and passenger boarding bridge / gateway removal" (data obtained synchronously from the flight ground support system), if all three operations are completed and the trolley has started the pushback action, it is determined to be "already in the pushback process", and the three-dimensional visual simulation system marks it with the "priority occupation" mark; aircraft that have not started the pushback action and are only included in the target pushback sequence are determined to be "pending pushback status" and do not enjoy priority occupation rights.

[0100] (2) Conflict detection and sorting adaptation: ① During conflict detection, if the planned path of the aircraft to be pushed out requires the use of a key node at the harbor entrance, and the time window of that node has been occupied by an aircraft that is already in the push-out process (including the safety buffer time), then it is directly determined that there is a "node exclusive conflict" between the aircraft to be pushed out and the aircraft that has already been pushed out, and it is marked as a general conflict (which can be avoided by adjusting the push-out time); ② During sorting adaptation, the three-dimensional visual simulation system synchronously feeds back the node occupancy constraint to the apron control pre-sorting main system, requiring the apron control pre-sorting main system to adjust the push-out of the aircraft to be pushed out. During the sequence, the estimated launch time of the aircraft to be launched will be postponed in advance to avoid the time window occupied by aircraft that are already in the launch process. The launch rhythm and path of aircraft that are already in the launch process shall not be adjusted; ③ Special case handling: If the aircraft to be launched has CTOT restrictions (cannot postpone the launch time), the system will link the three-dimensional visual simulation system to replan the launch path for it (such as through the backup channel inside the U-shaped bay, if it exists). If there is no backup channel, an early warning will be triggered to prompt the controller to intervene manually (such as coordinating the launch speed of aircraft that have already launched, or temporarily adjusting CTOT).

[0101] Visualization Adaptation: To facilitate controllers' intuitive understanding of the occupancy status and priority of a node, the 3D visual simulation system highlights key nodes at the U-shaped harbor entrance in orange (distinguishing them from the blue of ordinary key nodes and the red of conflicting nodes) in the 3D situational interface, and labels them as "Exclusive Node," "Currently Occupied Aircraft Identifier," "Occupancy End Time," and "Priority Occupancy Status" in the form of floating tags. In the electronic progress sheet interface, for aircraft waiting to push back at the U-shaped harbor stand, the list entry is marked with the prompt "Requires Exclusive Harbor Entrance Node." If there is a node occupancy conflict, it is simultaneously marked "Needs to Avoid Pushback of Already Pushed-Back Aircraft" and a suggested adjustment time is provided to ensure accurate judgment by controllers.

[0102] In this embodiment, considering the constraints of exclusive nodes at the entrance of the U-shaped harbor, the impact of towing tasks, and the requirements for aircraft type compatibility, the objective function of the optimization model can be quantified as (used to minimize the dynamic weighted total waiting time of aircraft at U-shaped harbor parking positions and aircraft at ordinary parking positions, while avoiding node exclusive conflicts): Min Z=Σ i=1 n [W i ×ω i ×Twait i +α×Tdelay i +β×U i ×Twait i ].

[0103] In addition to the three types of general constraints (spatiotemporal conflict constraints, operational priority constraints, and physical and operational rule constraints) mentioned in the aforementioned embodiments, the constraints also include specific constraints for aircraft at U-shaped harbor parking positions: U-shaped harbor exclusive constraints (applicable only to aircraft scheduled to depart from U-shaped harbor stands, i.e., U...) h =1, U j =1): For any two scheduled departing aircraft located at a U-shaped bay stand, their time windows for occupying exclusive nodes at the bay entrance do not overlap, i.e., Toccupy h ∩Toccupy j It is equal to the empty set, and any h ≠ j.

[0104] Where Z represents the dynamically weighted total waiting time. W i The basic weighting coefficient for the i-th planned departing aircraft (set by aircraft type: W for large E / F category aircraft) i =1.2, C / D class W i =1.0). Twait i Twait is the actual waiting time for the i-th scheduled departing aircraft. i =Tpush i -Tready i α is the delay penalty coefficient for delayed tasks (α=1.5, additionally weighting the delay caused by delayed tasks to avoid a surge in total waiting time). Tdelay i β represents the additional delay time caused by the towing task occupying taxiing resources for the i-th scheduled departing aircraft (0 if there is no towing impact). β is the weighting coefficient for aircraft at U-shaped bay parking positions (β=1.8, due to the node's exclusive nature, its waiting impact is greater, and it is optimized first). U i U-shaped harbor parking stand aircraft markings (U i =1 indicates that the i-th scheduled departing aircraft is located at a U-shaped bay gate, U i =0 indicates a non-U-shaped harbor parking position. (Toccupy) hand Toccupy j These represent the total occupancy time (including safety buffer) of the h-th and j-th scheduled departing aircraft at the U-shaped bay stand for exclusive access to the bay entrance. The values ​​of h and j range from 1 to p, where p is the number of scheduled departing aircraft at the U-shaped bay stand.

[0105] Among them, Toccupy h =La / v h a +Ts+△T×δ. Where La is the actual physical length of the exclusive node at the entrance of the U-shaped harbor (default 50m, adjustable for airport scenarios). h a v is the actual taxiing speed of the h-th scheduled departing aircraft at the exclusive node. h a =v base ×k h ×k met v base The basic taxiing speed for the node (fixed at 15 km / h, the speed standard for the U-shaped harbor node clearly defined in S500), k h The type speed correction factor (E / F category k) for the h-th planned aircraft. h =0.8, C / D class k h =1.0)k met For meteorological condition correction factors (normal weather k) met =1.0, rain / snow / strong wind k met =0.7). Ts is the safe buffer time for exclusive use of the node (fixed at 30s, adapted to the narrow and inconvenient turning characteristics of U-shaped harbor passages). △T is the additional delay time caused by the tractor task occupying this node (if the tractor is occupied, it is the remaining time occupied by the tractor task; otherwise, it is 0). δ is the tractor task occupancy indicator (δ=1 indicates that the node is occupied by the tractor task, δ=0 indicates that it is idle).

[0106] The objective function in this embodiment has the following advantages: (1) Accurately resolve U-shaped harbor node exclusive conflict and strengthen the bottom line of operational safety: By introducing a U-shaped harbor stand exclusive identifier and scenario weighting coefficient β, the waiting time of aircraft at U-shaped harbor stands is given higher weight, and the push-out efficiency of such aircraft is optimized first, avoiding chain conflicts caused by node occupation waiting; in conjunction with the exclusive constraint that "the occupation time windows of any two U-shaped harbor stands for exclusive nodes at the harbor entrance do not overlap", the mathematical level forces that only one aircraft is allowed to occupy the key nodes at the harbor entrance at the same time, which completely solves the technical pain point that the existing general objective function cannot adapt to the U-shaped harbor node exclusive demand and is prone to multiple aircraft competing for nodes, and significantly reduces the risk of push-out and entry conflicts in the U-shaped harbor area.

[0107] (2) Optimize multi-dimensional priority ranking to improve overall apron operation efficiency: The objective function integrates a three-dimensional weighted logic of "aircraft type basic weight + release status weight + U-shaped bay scenario weight". It not only considers the characteristic of E / F category large aircraft occupying more taxiing resources, but also highlights the practical priority of aircraft that have obtained release permission (CLD status). It is also more specifically adapted to the special operational needs of U-shaped bay stands, so that the ranking result is no longer a single-dimensional minimization of waiting time, but a global optimum that takes into account "general operating rules + practical priority + special scenario adaptation". Compared with the existing undifferentiated weighted objective function, the average waiting time of aircraft at U-shaped bay stands is significantly reduced, the overall utilization rate of apron taxiing resources is optimized, and the apron turnaround efficiency is avoided due to excessive waiting time of a single aircraft.

[0108] (3) Dynamically adapting to complex operating conditions and enhancing the robustness of the sorting scheme: By incorporating the towing task delay penalty coefficient α and the weather condition adaptation rules, the objective function can dynamically respond to the impact of complex operating conditions such as towing task occupancy nodes and rainy / snowy weather on the operation of the U-shaped harbor. The additional delay caused by the towing is amplified by α through weighting, prompting the towing to actively avoid the towing occupancy window during sorting. Weather changes are dynamically adjusted to adjust the node taxiing speed and accurately correct the occupancy time of the exclusive node at the harbor entrance, avoiding constraint failure caused by changes in operating conditions. Compared with the existing static objective function, this design makes the sorting scheme of the U-shaped harbor more adaptable to the dynamic operating characteristics of the apron, and significantly improves its robustness.

[0109] (4) Quantitative constraints ensure implementation and improve the reproducibility of the technical solution: The objective function transforms the operating rules of the U-shaped bay (node ​​exclusive use, priority use) into clear mathematical constraints and quantitative parameters (such as the weighting coefficient β of the U-shaped bay scenario being 1.8, the safe buffer time for node exclusive use being 30 seconds, and the physical length of the exclusive node at the bay entrance being 50 meters). All weight coefficients and constraints are consistent with the actual operating scenario of the apron and can be flexibly adjusted according to the U-shaped bay structure of different airports, avoiding the defects of existing experience-based sorting methods that are "fuzzy in rules and difficult to reproduce". This design upgrades the sorting optimization of the U-shaped bay from "qualitative judgment" to "quantitative calculation", ensuring that the technical solution can be accurately reproduced by those skilled in the art, and at the same time providing a clear mathematical basis for subsequent engineering implementation.

[0110] For scenarios involving aircraft scheduled to depart from U-shaped harbor stands, the iterative optimization steps for generating the initial rollout sequence, based on a dynamically weighted objective function and constraints, are executed as follows to ensure compatibility with the exclusive characteristics of U-shaped harbor nodes and multi-dimensional priority requirements: 1. Initial Sequence Generation The initial sequence is constructed based on the readiness baseline time (i.e., the time when the aircraft is ready or cleared for departure) of each scheduled departing aircraft, and incorporates priority rules specific to the U-shaped harbor scenario. The specific process is as follows: The ordering is based on the readiness time of each scheduled departing aircraft. The earlier the time, the higher the initial ranking, ensuring the rationality of the basic operational sequence. A multi-dimensional priority scoring mechanism is introduced, with scoring weights set according to the core needs of the scenario: aircraft scheduled to depart from U-shaped bay stands receive 20 points, echoing the scenario-based weighting logic; aircraft that have already received clearance receive 15 points, matching the practical rules for clearance priority; large E / F category aircraft receive 10 points, adapting to the resource occupation characteristics of large aircraft; aircraft with a calculated takeoff time (CTOT) of ≤30 minutes receive 12 points, those with 30-60 minutes receive 8 points, and those with >60 minutes receive 3 points, mitigating the risk of CTOT timeout; When processing aircraft with the same number of seats, the priority order is "planned departure aircraft at U-shaped bay stands > aircraft that have been released > large E / F category aircraft > those with earlier readiness baseline times are ranked higher" to ensure that key requirements of the scenario are implemented first. The aircraft are sorted in descending order of their total score (baseline score + multi-dimensional bonus points), and the output is a mixed initial sequence of aircraft scheduled to depart from both U-shaped bay stands and regular stands. The initial ranking and estimated pushback time of each aircraft are clearly defined.

[0111] (2) Candidate sequence evaluation The evaluation is performed in the order of "constraint verification first, then objective function calculation." Constraint verification follows the principle of "general before specific, hard constraints before soft constraints," ensuring that core hard constraints are implemented first while improving verification efficiency. The specific process is as follows: Constraint verification: Latest launch time constraint: The estimated launch time of each scheduled departing aircraft must not be later than the difference between its calculated takeoff time and the estimated taxiing time. Candidate sequences that do not meet this constraint are directly marked as discarded. Spatiotemporal conflict constraint: When the planned taxiing paths of any two aircraft in the set of aircraft to be sorted involve shared resources, the time windows for the two aircraft to occupy the resource do not overlap. If this condition is not met, the aircraft is marked as discarded. Operational priority constraint: When the taxi paths of a scheduled arriving aircraft and a scheduled departing aircraft intersect at a point, the estimated pushback time of the departing aircraft is later than the estimated time of the arriving aircraft passing through the intersection point. If this constraint is not met, the aircraft is marked as abandoned. Physical and operational rule constraints: These include allowing only one aircraft to occupy a single taxiway micro-segment and key node at the same time, bay area stand pushback to avoid adjacent positions, towing aircraft paths to avoid the main taxiing path of flights, and resource occupation time windows for E / F category large aircraft being adjusted by a coefficient of 1.2. If any sub-constraint is not met, it is marked as discarded. U-shaped harbor exclusive constraint: For any two U-shaped harbor parking positions, the time windows for occupying exclusive nodes at the harbor entrance do not overlap; if this condition is not met, the aircraft is marked as abandoned. Objective function calculation: For candidate sequences that pass all constraint checks, the dynamic weighted total waiting time Z is calculated according to preset parameters (including basic weight of aircraft type, weight of release status, weighting coefficient of U-shaped harbor scenario, penalty coefficient of towing delay, etc.). The contribution value of each sub-item weight is recorded synchronously during the calculation process to facilitate result traceability. Evaluation results record: Generate a structured evaluation report for each candidate sequence, clearly marking the constraint satisfaction status, objective function value Z, core conflict points (if any), and details of the time window occupied by the U-shaped harbor node.

[0112] 3. Optimal Sequence Selection From the candidate sequences that pass the evaluation, the final preliminary sorted sequences are selected according to the following rules: First priority: Only retain candidate sequences that fully satisfy all constraints (including general constraints and U-shaped harbor specific constraints), and exclude any conflicting sequences; Second priority: Among the sequences that satisfy the constraints, select the sequence with the smallest dynamically weighted total waiting time Z to ensure that the global optimization objective is achieved; Third priority: If there are multiple optimal candidate sequences with the same Z value, a second screening is conducted in the order of "shorter average waiting time for aircraft at U-shaped bay stands → shorter waiting time for released aircraft → more aircraft without additional delays due to towing" to balance the special requirements of the scenario with overall operational efficiency. Optimal sequence output: The final output preliminary push-out sorting sequence must clearly indicate the flight number, parking position type, estimated push-out time, U-shaped harbor node occupancy time window (including safety buffer), and the contribution value of each component of the objective function for each aircraft, so as to provide complete data support for the subsequent path planning and conflict detection of the 3D visual simulation system.

[0113] 4. Iteration Termination Condition The core termination condition is that no candidate sequence with a better objective function value Z is found in 5 consecutive iterations, or the number of iterations reaches a preset threshold (20 rounds by default, which can be dynamically adjusted according to the number of aircraft to be sorted). Special termination condition: If there is a candidate sequence generated in a certain round of iteration with a Z value ≤ 80% of the initial sequence Z value and that completely satisfies all constraints, the iteration can be terminated early to quickly lock in a high-quality solution; Iteration log recording: Each iteration synchronously records information such as the number of candidate sequences, the number of sequences that pass the constraint verification, the change of the optimal Z value, and the satisfaction of the U-shaped harbor-specific constraints, ensuring that the iteration process is traceable and reproducible.

[0114] Furthermore, the method also includes: Real-time monitoring of flight dynamics data and ground operation status enables dynamic adaptation and adjustment of the target rollout sequence, ensuring that the sequence always matches the actual operating conditions of the apron and avoids dynamic conflicts.

[0115] The apron control pre-sequencing main system is linked with the air traffic control CDM system, flight ground support system, 3D visual simulation system and flight flow management system to monitor flight dynamic data and apron operation status in real time, and establish a closed-loop mechanism of "continuous monitoring - trigger judgment - recalculation adjustment - synchronous update".

[0116] The apron control pre-sequencing main system serves as the core monitoring entity, establishing real-time data interaction with various related systems through a dedicated data interface. The data interaction frequency is set to once every 10 seconds (adapting to the dynamic changes in apron operations, balancing data real-time performance and system computing power consumption). Core monitoring content includes: (1) Flight dynamic data: Focus on monitoring the core parameters of each scheduled departing aircraft, such as TOBT (Target Wheel Stop Time), CTOT (Calculated Takeoff Time), Release Status (CLD / RDY), Estimated Pushback Time, Actual Pushback Time, and Actual Taxiing Time. The data is obtained synchronously from the air traffic control CDM system, NTFM system, flight flow management system, and flight ground support system. (2) Apron surface operation status: Focus on monitoring the dynamics of towing missions (mission initiation, execution, cancellation, completion), taxiing resource status (changes in occupancy / vacancy of sub-segments and key nodes), U-shaped bay gate node occupancy status, and actual aircraft operating trajectory (deviation from the expected trajectory). Data is obtained synchronously from the three-dimensional visual simulation system, towing scheduling system, and airport surface monitoring system. Anomaly prediction during monitoring: The apron control pre-sequence main system compares the monitoring data with the associated parameters in the current target exit sequence (such as the expected exit time and resource occupation time window) in real time. When the data deviation reaches the preset value of the corresponding trigger condition threshold, such as 80%, a "potential sequence adjustment warning" will pop up in advance on the electronic progress sheet interface to remind the controller to pay attention. The warning information includes the type of potential triggering event and the relevant aircraft identification.

[0117] When one of the following preset events is detected and the trigger threshold is met, the recalculation and adjustment of the target's sorting sequence will be automatically triggered. The specific judgment criteria and trigger thresholds for each event are as follows: a) Significant changes have occurred in the TOBT and CTOT times of key flights: Definition of critical flight: Specifically refers to a scheduled departing aircraft that has been confirmed by the controller for pushback sequence (marked "Confirmed" on the electronic progress sheet interface), is in the pushback preparation stage (RDY status), or has started the pushback process (the judgment criteria are consistent with the judgment of the pushback process of aircraft related to U-shaped bay stands in S500); Significant change judgment threshold: TOBT change magnitude ≥ 15 seconds (including early or late), or CTOT change magnitude ≥ 30 seconds (including early or late); if the change magnitude does not reach the above threshold, only the relevant data will be updated synchronously, and the sequence recalculation will not be triggered. Special Note: If a CTOT change results in the latest departure time of an aircraft being earlier than the estimated departure time in the current order, regardless of the magnitude of the change, a recalculation will be triggered directly to avoid affecting the normal takeoff of the flight.

[0118] b) A new haulage task arises or an existing haulage task is cancelled: New towing mission triggers: The planned path of a new towing mission occupies the expected taxiing path (including sub-segments, key nodes, and exclusive nodes at the entrance of the U-shaped harbor) of any aircraft in the current target launch sequence, and the resource occupation time windows of the two overlap (overlap duration ≥ 10 seconds), triggering a recalculation; if the resources occupied by the new towing mission do not overlap with the expected taxiing path of the aircraft, only the topology resource status of the 3D visual simulation system is updated, and a recalculation is not triggered; The original towing mission is cancelled: The taxiing resources occupied by the original towing mission (related to the aircraft's expected taxiing path) are released, and the occupation of these resources has caused the corresponding aircraft's sorting adjustment (such as delayed pushback). This triggers a recalculation, re-optimizes the sorting of the aircraft and related aircraft, and reduces unnecessary waiting time.

[0119] c) The aircraft failed to perform pushback or taxiing as scheduled: Failure to launch as scheduled: If the actual launch time of the aircraft (the wheel chock removal completion time obtained from the ground support system) deviates from the scheduled launch time in the current target launch sequence by ≥t1 (including delays and advances), a recalculation is triggered; t1 is the first preset time, for example, it can be 20 seconds.

[0120] Failure to taxi as scheduled: If the actual taxiing time of the aircraft (from the actual pushback time to the arrival at the handover point / runway) deviates from the estimated taxiing time calculated by S300 by ≥t2, and this deviation causes the resource occupation time window of the aircraft to overlap with that of subsequent aircraft, a recalculation is triggered; if there is only a time deviation and no time window overlap, only the estimated arrival time is updated, and a recalculation is not triggered. t2 is a second preset time, for example, it can be 30 seconds.

[0121] After the recalculation adjustment is triggered, the apron control pre-sequence main system will automatically execute the following process without requiring manual triggering by controllers, while retaining the manual intervention interface: Original sequence suspension and warning prompt: The apron control pre-sequence main system immediately suspends the execution of the current target exit sequence (the electronic progress sheet interface is marked "Sequence adjustment in progress", and controllers are prohibited from clicking the "One-click adoption" or "Manual adjustment" controls). At the same time, an audible and visual warning pops up on the electronic progress sheet interface and the 3D situation interface of the 3D visual simulation system, prompting "Apron status changed, sequence is being recalculated, please operate later", and displays the specific event that triggered the recalculation (such as "Flight XXX CTOT delayed by 40 seconds, triggering sequence recalculation"). Recalculation Modeling and Preliminary Sequence Generation: The apron control pre-sequence main system re-calls the S200 MILP optimization model, and based on the latest flight dynamic data (updated TOBT, CTOT), surface operation status (tug aircraft tasks, resource occupation changes), and actual aircraft operation data, reconstructs the optimization objective function and constraints to generate a new preliminary rollout sequence. Conflict detection and sequence optimization: The newly generated preliminary exit sorting sequence is resent to the 3D visual simulation system for secondary conflict detection; after the detection is completed, the conflicting sequences are optimized and adjusted according to the S400 hierarchical adjustment logic to generate a new conflict-free target exit sorting sequence. Sequence synchronization update and display: After a new target is launched and a sorting sequence is generated, the original sequence is automatically replaced, and the display content of the electronic progress sheet interface and the 3D situation interface of the 3D visual simulation system is updated synchronously. The "Sequence adjustment in progress" mark is cleared and the operation permissions of all interactive controls are restored. At the same time, the "Sequence updated" mark is displayed on the electronic progress sheet interface, and a "View adjustment log" control is provided to facilitate controllers to view the recalculation reasons, adjustment details, and before-and-after sequence comparisons. Special case handling: Recalculation failure: If a conflict-free sequence cannot be generated due to data anomalies or multiple conflicts, the apron control pre-sequencing main system will immediately trigger a manual intervention warning, push the reason for the recalculation failure and details of the abnormal data to the controller's interface, prompt the controller to manually adjust the sequence, and record the failure log for subsequent troubleshooting. Multiple triggers in a short period of time: If recalculation is automatically triggered 3 or more times within 1 minute (excluding recalculation triggered manually by the controller), the cooling mechanism will be automatically activated (cooldown time is 30 seconds). During the cooling period, only data will be continuously monitored and recalculation will not be triggered repeatedly to avoid computing power overload. After the cooling period ends, if the triggering conditions still exist, recalculation will be performed once.

[0122] In addition, to further ensure the engineering adaptability, traceability, and operational flexibility of this step, the apron control pre-sequencing main system performs the following additional supporting operations: All recalculation and adjustment processes (triggering events, triggering times, recalculation sequence before and after, adjustment details, and data sources) are automatically recorded in the system log, which is integrated with the adjustment log of S400 and the operation log of S500 to achieve full-process traceability and meet the operation and maintenance needs of airport control. It supports controllers to manually pause and resume the recalculation process, and can also manually trigger the recalculation, or manually adjust the newly generated target to exit the sorting sequence after the sequence recalculation is completed (the operation logic is consistent with S500), taking into account both automation and operational flexibility. If the recalculation triggering event involves aircraft at U-shaped bay stands (such as changes to the aircraft's TOBT or towing operations occupying bay entrance nodes), the recalculation process will prioritize the "priority protection of exclusive bay entrance nodes" rule supplemented by S500 to ensure rule consistency.

[0123] This invention also provides an electronic device, including: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being configured to perform the method described in this invention.

[0124] This invention also provides a computer-readable storage medium storing computer-executable instructions for performing the methods described in this invention.

[0125] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this invention can be achieved, and this is not limited herein.

[0126] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A pre-sequencing method for aircraft pushback from apron control, characterized in that, The method includes the following steps: Obtain flight dynamic data and parking space allocation data for multiple aircraft in a set of aircraft to be sorted; Based on the flight dynamic data, parking space allocation data, and preset apron operation constraints, a preliminary rollout sorting sequence is generated for the set of aircraft to be sorted, wherein the preliminary rollout sorting sequence includes at least the estimated rollout time of each scheduled departing aircraft. The initial launch sequence is sent to the 3D visual simulation system so that the 3D visual simulation system can plan taxi paths for each aircraft based on the expected launch time and perform conflict detection on the taxi paths of all aircraft within a preset future time period. Receive conflict detection results from the three-dimensional visual simulation system. If the conflict detection results indicate that there is a path conflict, adjust the initial exit sorting sequence based on the conflict detection results to generate a conflict-free target exit sorting sequence. The target is output in a sorted sequence to the display interface and visualized as a reference for control instructions.

2. The method according to claim 1, characterized in that, When generating the initial rollout sorting sequence, the optimization objective is to minimize the overall rollout waiting time; the overall rollout waiting time is the sum of the differences between the estimated rollout time of all scheduled departing aircraft and their corresponding ready or cleared-for-departure times.

3. The method according to claim 2, characterized in that, The step of generating the initial exit sorting sequence is achieved by solving a constrained optimization problem with the overall exit waiting time as the optimization objective; the constraints of the constrained optimization problem include at least one of the following: Spatiotemporal conflict constraint: If the planned taxiing paths of any two aircraft in the set of aircraft to be sorted involve shared resources, the time windows in which the two aircraft occupy the shared resources shall not overlap. Operational priority constraint: If the taxi paths of a scheduled arriving aircraft and a scheduled departing aircraft intersect at a point, the estimated pushback time of the scheduled departing aircraft shall be later than the estimated time of the scheduled arriving aircraft passing through that intersection point; Physical and operational rule constraints include at least one of the following: only one aircraft is allowed to occupy a single taxiing resource at any given time; aircraft pushback from bay area stands must avoid adjacent aircraft; tow routes must avoid the main taxiing path of flights; and latest pushback time constraints.

4. The method according to claim 2, characterized in that, For aircraft located at U-shaped bay positions in the set of aircraft to be sorted, if the planned pushback path for such aircraft requires the use of critical nodes at the bay entrance, the 3D visual simulation system executes the following rules in path planning and conflict detection: The key nodes at the harbor entrance are identified as key resources with exclusive use attributes; When allocating a time window for the use of a critical resource to an aircraft, if the critical resource has already been used within the preset future time period, the subsequent time window shall not overlap with the already allocated time window, and priority shall be given to ensuring the right of an aircraft that is already in the pushback process to use the critical resource. The key node at the entrance of the harbor refers to the only intersection point connecting the internal taxiing area of ​​the U-shaped harbor with the main taxiway of the apron.

5. The method according to claim 4, characterized in that, When the set of aircraft to be sorted includes scheduled departing aircraft located at U-shaped bay stands, the optimization objective for generating the initial rollout sorting sequence is to minimize the dynamically weighted total waiting time, and the corresponding objective function is: Min Z=Σ i=1 n [IN i ×ω i ×Twait i +α×Tdelay i +β×U i ×Twait i ]; The constraints include: (1) Spatiotemporal conflict constraint: If the planned taxiing paths of any two aircraft in the set of aircraft to be sorted involve shared resources, the time windows of the two aircraft occupying the shared resources shall not overlap. (2) Operational priority constraint: If there is an intersection between the taxi paths of the planned arriving aircraft and the planned departing aircraft, the estimated pushback time of the planned departing aircraft shall be later than the estimated time of the planned arriving aircraft passing through the intersection; (3) Physical and operational rule constraints: including at least one of the following constraints: only one aircraft is allowed to occupy a single taxiing resource at the same time; the aircraft must avoid adjacent positions during pushback in the bay area; the towing path must avoid the main taxiing path of the flight; and the latest pushback time. (4) The time windows for any two aircraft scheduled to depart from the U-shaped bay stand do not overlap with each other for the exclusive node at the bay entrance. Where Z is the dynamically weighted total waiting time, and n is the total number of all scheduled departing aircraft; W i ω is the base weighting coefficient for the i-th scheduled departing aircraft. i Twait is the release status weighting coefficient for the i-th scheduled departing aircraft. i Tdelay represents the actual waiting time for the i-th scheduled departing aircraft; α is the towing task delay penalty coefficient. i β represents the additional delay time caused by the towing mission occupying taxiing resources for the i-th scheduled departing aircraft, and β is the weighting coefficient for aircraft at U-shaped bay stands, with i ranging from 1 to n.

6. The method according to claim 3 or 5, characterized in that, The initial sorting sequence is generated through iterative optimization, including: An initial sequence is generated based on the preparation or clearance time of each scheduled departing aircraft; Using a heuristic search algorithm, starting from the initial sequence, the following process is iteratively executed: generating new candidate sequences, evaluating whether the candidate sequences satisfy the constraints and the total waiting time for the candidate sequences to be released; From all evaluated candidate sequences, the candidate sequence with the minimum total launch waiting time that meets the constraints is selected as the initial launch sorting sequence.

7. The method according to claim 1, characterized in that, The three-dimensional visual simulation system sets up a topology model of the organic scene gliding path, which is constructed based on a node-segment model, wherein: Define the physical intersections, waiting points, and apexes of curves of the taxiway as critical nodes; Define the taxiway segment between two adjacent key nodes as a road segment; If the length of a road segment exceeds a preset threshold, virtual nodes are inserted on that road segment at preset intervals to divide the road segment into multiple sub-segments.

8. The method according to claim 7, characterized in that, When the 3D visual simulation system plans the gliding path, it performs the following steps: Check if there is a predefined fixed taxiway that matches the origin and destination of the current aircraft; if there is, use the predefined fixed taxiway as the planned path of the current aircraft; if there is not, use the shortest path algorithm to automatically plan a route as the planned path of the current aircraft based on the topology model. Based on the total length of the planned path and the preset average aircraft taxiing speed, calculate the estimated time for the current aircraft to taxi along this path.

9. The method according to claim 1, characterized in that, The collision detection performed by the 3D visual simulation system includes at least one of the following types: Handover point conflict detection: Detects whether the estimated transit times of different aircraft at the same control handover point conflict; Taxi path conflict detection: Detects whether the time occupied by different aircraft on a shared taxi path segment overlaps; Aircraft position operation conflict detection: Detects whether there is a conflict between the pushback and entry times of aircraft between adjacent aircraft positions or aircraft positions with operational constraints.

10. The method according to claim 1, characterized in that, The method further includes: The target launch sequence is synchronously pushed to the three-dimensional situation interface of the three-dimensional visual simulation system for visualization; the visualized content includes at least the aircraft identification, the estimated launch time and the corresponding future taxiing path.

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