Automatic Ground Collision Avoidance System Trajectory Prediction and Control for General Aviation

Abstract

Despite improvements in technology and safety systems, general aviation remains a relatively unsafe method of travel. Specifically, terrain collision (the impact of the aircraft with the ground) accounts for a large majority of fatalities and serious injuries in aircraft accidents and largely contributes to the poor safety record. During Controlled Flight Into Terrain (CFIT), the aircraft has the aerodynamic ability to avoid terrain but factors such as pilot loss of situational awareness or distraction lead to terrain collision. Controlled Flight Into Terrain (CFIT) remains a leading cause for aircraft total loses and number of fatalities in general aviation. Fortunately, automatic safety systems which may alleviate CFIT are being developed and tested primarily for USAF fighter and performance limited aircraft, and unmanned aerial vehicles. The primary component of a ground collision avoidance system (GCAS) is the trajectory prediction algorithm and actuator control design, and its accuracy for modeling an aircraft’s performance characteristics throughout the GCAS maneuver. The continuously changing aircraft dynamics impact the aircraft’s trajectory paths and durations of possible GCAS maneuvers to avoid terrain collision introducing a wide range of initial conditions that must be accounted for within the model for safety assurance. There are currently no known Automatic GCASs (Auto GCASs) fielded or in the literature for general aviation. Therefore, if general aviation terrain collision is to be successfully mitigated by an Auto GCAS, the trajectory prediction and control systems must be systematically tested, evaluated, and verified across a wide range of possible flight envelope conditions to provide necessary Auto GCAS benchmarks for autonomy and safety. This work presents initial analyses and results to provide data to direct system designers as to the best approach to solve these types of problems given their individual set of requirements and aircraft. The research presented in this paper focuses on the analysis of these design choices and their effects on the overall safety and accuracy of an Auto GCAS model for trajectory prediction and control for a fixed-wing general aviation aircraft. The study is conducted in a real-time six degree of freedom (6DoF) flight simulation using a Cessna 172 aircraft model.