Research On Trajectory Optimization Of Continuous Descent Approach Based On Merge Point

Continuous Descent Approach(CDA) is a new control operation technology that’s recommended by ICAO in the terminal area, whose performance is better than the traditional step down approach procedure.On deep analysis of CDA operation principles, from the optimization problem of the CDA flight trajectory based on constant decline angle, the advantages and disadvantages of different CDA trajectory algorithms are analyzed, CDA flight trajectory is optimized by using Gauss pseudo-spectral method in distance and time about the flight control parameters. the CDA operation procedure based on the merge point is proposed,CDA flight process is optimized by time decision algorithms.The main research work includes:Firstly, the CDA flight trajectory is divided into two phases, cruise and descent, time optimization CDA trajectory based on Gauss pseudo-spectral method is simulated by using GPOPS tool and selecting B737-800 model.The TOD of aircraft, the control curve of approach speed and the fall time are obtained.Secondly, under the same initial conditions, 16 CDA trajectories are selected in the automatic control vertical navigation(VNAV) and pilot control VNAV mode, and 8 CDA trajectories and one traditional step down approach trajectory are selected randomly in different models of the terminal area, whose time is compared. The results show that the CDA trajectory based on Gauss pseudo-spectral method is better than others. Time optimization CDA flight trajectory of the B737-500 and B767-400 by Gauss pseudo-spectral method are obtained, whose CDA trajectory structure and fall time are compared.Finally, according to instrument approach procedures of Tianjin International Airport, CDA flight procedure based on the merge point is established, which provides distance information of CDA for the traffic flow of the different sequencing legs, the results show that procedure based on the merge point increases the traffic volume. Decision algorithms based on the merge point provide time to the pilots, the approach aircrafts are better managed for controllers, efficient and ordered management of the flights are realized, CDA control method is optimized.