Research And Implementation Of ACAS X System Surveillance And Tracking Module And Threat Resolution Module

The airborne collision avoidance system is an important part of ensuring flight safety.Civil aviation aircraft have been required to install the airborne collision avoidance system.With the increasingly complex flight environment,the widely used airborne collision avoidance system TCAS II（Traffic Collision Avoidance System II）can no longer meet people’s requirements for flight safety.The new generation of airborne collision avoidance system ACAS X（Airborne Collision Avoidance System X）has a major update on its surveillance tracking technology and collision avoidance logic on the basis of TCAS II.Based on the ACAS X minimum operating performance standard DO-385,this thesis studies two important algorithm modules of ACAS X,the Surveillance and Tracking Module and the Threat Resolution Module.The main work includes the following aspects:1.Under the framework of ACAS X system,this thesis studies the signal format and data format of the surveillance sources of ACAS X system including Automatic Dependent Surveillance-Broadcast（ADS-B）and secondary surveillance radar（SSR）.Three surveillance states of the hybrid surveillance system formed by the combination of ADS-B and secondary radar are introduced,and the transition conditions between the three surveillance states are studied.2.After studying the Surveillance and Tracking Module（STM）to obtain the input data,through 14 STM algorithm entry points to complete the process including ownship data processing,intrusion aircraft track file generation,coordination data processing and other processes and the process of getting the STM report.In the process of track correlation,the method of position correlation and image correlation is mainly studied;in the process of track update,Kalman filter is used to update the vertical state of the aircraft and the intruder,and the unscented Kalman filter is used to update the horizontal state.process,and use matlab to simulate verification and analysis,and get a good surveillance and tracking effect.3.The Threat Resolution Module（TRM）is studied to get the optimal decision process through the process of state and cost estimation,action selection,coordination selection,track threat assessment,and display logic determination after getting the STM report.The selection strategy of global Resolution Advisorie（RA）in the case of multiple intruders is studied.The Markov Decision Process（MDP）modeling process of ACAS X collision avoidance process is focused on,and the MDP problem is solved using dynamic programming and tested by simulation in matlab,and the offline cost table visualization results of the corresponding scenario are obtained.4.Finally,the STM and TRM are simulated and tested.The STM and TRM test programs are written separately to perform simulation tests on STM and TRM.STM shows the test scenes by generating STM reports and extracting the relative heights and relative distances from them.For TRM,input the generated STM report and get the trajectory status code and global RA of the whole process by TRM test program,and combine with the test scenario to show the RA selected by TRM in different flight states.