Autonomous collision avoidance based on aircraft performances estimation

The paper describes a resolution manoeuvre definition algorithm for a Sense and Avoid (S&A) system, in which the avoidance manoeuvres are the step variations in the heading angle command of the Flight Path Control System (FPCS). The value of these commands is optimised in order to get the minimum step command value necessary to keep a minimum predefined separation between the ownship and the threat. The computation of the separation distance between the ownship and the threat is based on the estimation of the future trajectory. This estimation is obtained from the response of the linear model of the aircraft modified in order to get the results as close as possible to the nonlinear behaviour of the aircraft. The defined algorithm is tested through simulations in Matlab/Simulink^® environment by considering some head-on conflict scenarios with a flying threat approaching from different directions. The threat considered is an aircraft that communicate its state to the system through its Automatic Dependent Surveillance-Broadcast (ADS-B) mode S transponder.