3D trajectory optimization for UAS insertion in civil non-segregated airspace

The use of UAS (Uninhabited Aerial System) in civil missions addresses quite a number of questions related to safety, security and economics, but the most critical challenge the civil UAS will face is the insertion into civil airspace. Avoiding collisions between aircrafts, expediting and maintaining an orderly flow of air traffic are very important goals for Air Traffic Management (ATM). The methodology we propose matches aeronautical science and operation research with ATM constraints and it is based on a two phases procedure: strategic and tactical. The strategic phase is based on Mixed Integer Linear Programming (MILP) and the Travelling Salesman Problem (TSP) method; it is performed off-line and gives as output a basic 3D route in order to allow the UAV to fly over N target points selected by the operator, avoiding fixed obstacles and minimizing an assigned cost function (fuel consumption, time and environmental impact). Once computed the route, the tactical phase starts, which is entirely performed on-line during flight. Civil air traffic constraints (minimum separation) are taken into account using TAR (Traffic Avoidance Resolution) module that combines a simple geometric computation with a TSP time extension model. The results coming from simulation are analyzed using Computer Graphic tools in order to easily and rapidly evaluate the performances of the proposed model. Separation between the UAV and physical obstacles, no fly-zones or other aircrafts populating the scenario, can be evaluated. Moreover, results coming from optimization such as trajectory and the associated fuel consumption, time or environmental impact of the mission are displayed.