Trajectory Optimization Of Continuous Descent Approach (CDA) And Analysis Of Top Of Descent

Continuous descent approach(CDA)is an approach trajectory management technology promoted by ICAO,which reduces the times of aircraft attitude changes,cut down noise,at the same time,the fuel consumption and exhaust emission are decreased.Compared with the traditional approaches,the CDA operation requires pilots to use ground-air flight dynamics parameters to plan approach trajectories at the TOD,and needs the real-time share of flight dynamics information and aeronautical operational parameters to achieve CDA.Based on the deep analysis of CDA operation principles,combines with aircraft performance model and 4-D trajectory technology,the time optimal CDA model and algorithm are proposed.In this model,the vertical trajectory profile and velocity profile,as well as operation time and horizontal path distance of TOD to runway entrance are obtained by MATLAB simulation.Then,compared with the traditional step down trajectory,the results show that the optimal CDA trajectory has obvious advantages in horizontal approach distance and operation time.In order to optimize the CDA trajectory on the lateral path,a dynamic CDA model is proposed.The avionics system utilizes the real-time location information and function optimization objectives in the aircraft approach process to obtain the optimal CDA trajectory,which can be converted into a set of waypoints in the terminal airspace that guide the aircraft to descend continuously.According to the instrument approach procedure of Tianjin Binhai International Airport,the dynamic CDA model is designed,and the function optimization target is the total amount of carbon emission during the descent approach.The B737-800 model is selected to simulate,the results show that the first 30 CDA effective trajectories from TOD to FAF with the optimal value.Compared with the instrument approach procedure,the dynamic CDA operation can effectively reduce aircraft carbon emissions.Then,it compares with the traditional CDA trajectory,and analyzes the CDA trajectory of different TODs.Finally,the situation of multiple arrival aircrafts is taken into consideration,the conflict resolution method is put forward,and the validity of the method is proved by the simulation of two approach aircrafts with MATLAB.