Green trajectory optimization of aircraft in terminal area

Air transport is an important pillar in the field of comprehensive transportation in China, and the research on its green operation is of great significance to sustainable development. To achieve green optimization and reduce carbon emissions, the trajectory of the aircraft in the terminal area was optimized, which effectively reduced carbon emissions and drew effective conclusions. The influence of the flight in the terminal area on the environment was explored, and the engine emission model was established. Based on the existing automatic dependent surveillance-broadcast（ADS-B） data and the cruise performance of aircraft A321, the data were analyzed and summarized. An integer programming model was established to divide flight segments and study the specific circumstances of the aircraft in the flight segment. The trajectory emission model was obtained by considering the two states of changing aircraft altitude and keeping horizontal flight and discussing the length of horizontal distance between flight segments. Then, the constraints were established according to the model assumptions and navigation rules, and the particle swarm optimization (PSO) algorithm was used to solve the problem. The model increased the altitude layer change constraint, optimized the flight state, reduced the control load, and lowered the carbon emission by 8.45% after trajectory optimization. By comparing the trajectory before and after optimization, it was found that under the goal of reducing emissions, the approach strategy of continuous descent was more efficient than the strategy of gradient descent.