Dynamic optimal UAV trajectory planning in the National Airspace System via mixed integer linear programming

Abstract

Unmanned air vehicles (UAVs), which have been popular in military context, have recently attracted attention of many researchers because of their potential civilian applications. However, before the UAVs can be used for civilian applications, a systematic integration of UAVs in the National Airspace System (NAS) is needed that can allow safe operation of UAVs along with other manned aircrafts. One of the critical capabilities needed for safe operation of the UAVs in the NAS is the ability of UAV to carry out sense and avoid task which would allow the UAV to amend its path to avoid collision with other aircrafts. Despite recent technological advances, such as availability of automatic dependent surveillance broadcast that can transmit position of an aircraft to others in the vicinity, planning a collision-free path autonomously is still challenging in a dynamic environment. The objective of this paper is to develop a methodology for discovering a path for the UAV that meets mission goals, avoids collision, is optimal in terms of path length and, more importantly, is feasible. The paper formulates the problem of path planning using the mathematical paradigm of mixed integer linear programming and provides a solution strategy for solving this problem in the dynamic sense. The tasks of avoidance of obstacles and waypoint navigation are incorporated as constraints in the MILP problem. The paper presents the solution of the MILP problem and verifies the performance of the proposed methodology with regard to optimality of the solution and computational time requirement via several simulated scenarios of different complexities.