Study On Collision Risk Model In Free Flight And Calculation Software Programming

The main problem studied here is collision risk calculation between aircraft in free flight.In free flight, aircraft are free to choose flight track, speed and heading, which can make full use of airspace resources. To guarantee flight safety, it is needed to evaluate collision risk in free flight. The main content and innovation is as follows:Establishing collision risk model based on position error. The distribution feature of position error caused by error factors is analyzed, collision slab is established, and collision risk is calculated with the Monte Carlo method.Establishing the piecewise function model of collision risk based on Wiener process.Considering the stage of airborne collision avoidance system, the relative distance inside and outside of the alarm zone is considered as the general Wiener process and the Ito process respectively to find out the risk of different initial state.Establishing event tree model. Building event tree of collision under free flight, different methods to the sub-events, including aircraft conflict, avoidance system failure, and pilot intervention failure, is used to figure out the overall risk of a certain airspace.Establishing a synthesized collision risk model based on Bayesian network. Ideas such as expectation-maximization algorithm(EM) is used to solve the prior probability of event nodes and then the aircraft collision risk, and to figure out the risk under a certain safe distance.Making the free flight collision risk model calculation software to seek a fast way to collision risk under different conditions. This part includes the function of this calculation software, the composition of the structure, and the instructions for use.