Air Route Network Generation Based On Traffic Assignment

The high-speed development of air transport industry will continue to grow rapidly in the coming decades.Under the condition of limited airport resources and airspace capacity,the ever-expanding traffic demand will lead to aircraft delays,traffic congestion and even flight cancellation.Air route network is the carrier to realize air traffic transportation for civil passenger and freight transportation.Its structure directly affects actual operation of transportation,and the traffic situation on air route network is an important basis for examining the structure of airway network.Therefore,air route network generation on traffic assignment has become an urgent research topic in airspace planning technology of air traffic field.The paper expounded the research status of air route network generation,traffic assignment and bi-level planning,and introduced the basic theory of complex networks and the related theories of bi-level programming.The innovation of the paper introduced the traffic flow demand into air route network.It not only introduced the demand between the airports as the basis for air route network generation,but also introduced the distribution of traffic volume in air route network into air route network.The Bi-level programming model is used to link the static air route network structure generation with the dynamic air route network operation from the perspective of air route network system planner and air route network system user.The upper layer model of bi-level programming is established by using air route network generation sub-model and air route network optimization sub-model,and the lower-layer model is established by the traffic assignment model.In the aspect of solving the sub-model of air route network generation,the paper introduced Weighted Neighbor Set Information Allocation Index WNSIA of air route network structure and traffic assignment into air route network generation,which proved that Weighted Neighbor Set Information Allocation Index WNSIA is more accurate.Sexuality,and it used to predict the similarity index of air route network nodes pairs.The improved network topology generator is used to generate air route network topology,and the optimal route search algorithm based on the preference is used to search the path in air route network topology to generate the initial air route network.In the aspect of solving the optimization model of air route network,the paper optimized the initial air route network from the aspects of air route network operation cost,flight conflict coefficient and dynamic non-linear coefficient.It adopted NSGA-III algorithm to solve the problem and transmits air route network structure to the lower layer model.The lower layer model used the K shortest path search algorithm to search for paths in air route network,completes traffic assignment,and transmitted the traffic assignment and the changed air route network structure to the upper layer model.Based on the Python platform NetworkX complex network analysis library,the paper conducts research on air route network generation in China.The simulation is verified by the laboratory network tool developed by the laboratory.The geographic information system platform ArcGIS is used to display the image information.The traffic flow was simulated by the case of an air route network consisting of 57 airports,383 air route points,635 air segments,226 air routes and 187975 airport-pairs' demands in the flight information region of Beijing and Shanghai in the Chinese mainland airspace.After air route network is generated,there are 453 air route points and 521 flight segments.And after optimization of air route network,average moving distance is 31.104 kilometers.After traffic assignment,there are 329 air route points and 507 flight segments.And the complex network evaluation index is used to analyze the changes of the air route network structure.It is found that the air route network is gradually simplified,the node connectivity becomes larger,the density is increased,the network invulnerability is improved,and the network accessibility is improved.Finally,the paper evaluates air route network structure and traffic assignment results by comparison with existing air route network,the operating cost of traffic assignment decreased by 22.920%,the coefficient of flight conflict decreased by 19.723%,and the dynamic non-linear coefficient decreased by 7.423%.