A Tactical Conflict Detection and Resolution Method for En Route Conflicts in Trajectory-Based Operations

Abstract

In trajectory-based operation (TBO), the four-dimensional trajectories (4DTs) of aircraft are shared with all flight-related stakeholders, which makes flights visible and controllable and helps flights arrive at a location within a fixed time range. With the technical support from TBO, the operation of flights in a route sector will be more efficient and the air traffic volume will increase. However, more flights will also result in more flight conflicts. In this study, a deterministic conflict detection and resolution (CDR) module is established to assist air traffic controllers in detecting and resolving high-density conflicts rapidly and in advance. In the conflict detection (CD) submodule, a spatial data structure with low time complexity, the R tree algorithm, is used. R tree can effectively reduce the comparison number between the 4DTs of all aircraft. The experiment results show that the computing time of the R tree presents a logarithmic curve with the increase in the number of aircraft and the efficiency of the CD is more significantly improved. In the conflict resolution (CR) submodule, considering the aircraft performance and terrain constraints, the Monte Carlo tree search (MCTS) algorithm is proposed to solve the problem of huge search space and to quickly provide an effective resolution policy for pairwise conflict. The simulation results in dense airspace indicate that the MCTS-based CR algorithm has good performance in terms of safety and efficiency.