Autonomous sense & avoid capabilities based on aircraft performances estimation

An autonomous navigation system integrating both the path following and the autonomous sense & avoid functions is presented in this article. The sense & avoid algorithm was developed to provide an avoidance manoeuvre that ensures a minimum separation between the ownship and all other agents during its execution in a multiple flying threats scenario. The resolution manoeuvre is defined as step variations in the heading angle and altitude autopilots commands. The commands are optimised in order to get the smallest step command necessary to keep a minimum predefined separation between the ownship and the threats. Its computation is based on the estimation of the future trajectory of all the agents and, therefore, on the estimation of aircraft performance during the manoeuvre. The suggested resolution manoeuvre is updated at 1 Hz in order to take into account any unpredictable changes of the threat trajectories. The obtained heading and altitude change commands are displayed on a novel human–machine interface to support the pilot in the planning of the avoidance action. The proposed sense & avoid system is modelled in a Matlab/Simulink® environment for a Piper J3 Cub 40 model aircraft. The threats considered are aircrafts that communicate their states to the system through their Automatic Dependent Surveillance-Broadcast mode S transponders.