Research On Trajectory Generation,Tracking And Optimization About Continuous Descent Operations

Due to the global civil aviation industry has gradually entered the fast lane of its development.Under the premise of safe operation,how to meet the requirements of energy saving,emission reduction and noise reduction as much as possible and achieve goal of green flight have become the focus of the civil aviation industry.So,foreign countries have carried out the verification and analysis of Continuous Descent Operations,which are based on the four-dimensional trajectory.The 4D trajectory is the core and key of trajectory-based operation concept,and it ensures the effectively implement air traffic management under high density,small interval and high flow conditions.In view of this,this paper deeply conducts the research on trajectory generation,tracking and optimization which is about continuous descent operations.Firstly,through analyzing the vertical profile of continuous descent operations to conduct a special aircraft intent model.Combined with the particle model,performance data and meteorological model,using the inverse integral strategy and the fourth-order Runge-Kutta method,the trajectory generation about continuous descent operations is realized.The simulation results show that the profiles generated by this method have high consistency with the profiles generated by the flight simulator.Secondly,based on the LNAV/VNAV tracking logic and tracking logic selected table which is used to control the conversion between different logic,a trajectory tracking method about continuous descent operations is proposed.Through altitude and speed to select the corresponding tracking selection table.Based on the relationship between the trajectory error and the threshold to select the relevant tracking logic,and control bank angle,thrust and drag by gain.From the horizontal tracking and the vertical tracking to realize 4D trajectory tracking.The simulation results show that the trajectory after tracking is basically consistent with the reference trajectory,especially in horizontal trajectory and altitude profile.Then,based on the Gaussian pseudospectral method,a trajectory optimization method about continuous descent operation is proposed.The essence of the 4D trajectory optimization is the optimal control problem.Therefore,the optimal control problem is transformed into a nonlinear programming problem.Using the fuel consumption or time as objective function,and the sequential quadratic programming method is used to solve the nonlinear programming problem.The simulation results show that this method can generate optimized continuous descent profile.Finally,to the goal of 4D trajectory analysis and fusion of the above techniques,a 4D trajectory management system is developed,which is based on Monte Carlo simulation technology.Taking arrival flights as examples,whose entry fix is ATAGA at Guangzhou Baiyun International Airport,a case study is conducted.And the result indicates that even without the interruption of air traffic controllers and pilots,and separation restriction is 30 km,the separation between aircrafts at the Initial Approach Fix is not less than 12 km,and the probability for it is 99.78%,this situation meets the safety requirement of operations.