Probabilistic Strategic ConflictManagement for 4D Trajectories in FreeRoute Airspace The expected growth of air traffic in the following decades demands the implementation of new operational concepts to avoid current limitations of the air traffic management system. This paper focuses on the strategic conflict management for fourdimensional trajectories (4DT) in freeroute airspace. 4DT has been proposed as the future operational concept to manage air traffic. Thus, aircraft must fulfil temporary restrictions at specific waypoints in the airspace based on time windows. Based on the temporary restrictions, a strategic conflict management method is proposed to calculate the conflict probability of an aircraft pair (that intersects in the air) and to calculate temporaryblocking windows that quantify the time span at which an aircraft cannot depart because one conflict could occur. This methodology was applied in a casestudy for an aircraft pair, including the uncertainty associated with 4DT. Moreover, a sensitivity analysis was performed to characterise the impact of wind conditions and speed control on the temporaryblocking windows. The results concluded that it is feasible to propose 4DT strategic deconfliction based on temporaryblocking windows. Although, uncertainty variables such as wind and speed control impact on the conflict probability and the size of the temporaryblocking windows.

Three Dimensional Collision Avoidance for Multi Unmanned Aerial Vehicles Using Velocity Obstacle Recently, multiUAV systems are attracting growing interests. It offers wide range of applications in civilian and military environment, carrying out dangerous missions that manned aircraft cannot offer. Currently, an important challenge is the collision avoidance algorithm. The idea is to use the collision avoidance algorithm to control the multiUAV systems. This will guarantee the safety of the UAVs. The UAVs will complete the missions without colliding with any moving or static obstacles. This topic has motivated the development of various collision avoidance algorithms. In this paper, we proposed some improvements on the threedimensional velocity obstacle algorithm proposed in Jenie et al. (J. Guid. Control Dyn. 39(10), 2312xe2x80x932323 25). Our improvements are threefold. First, we indicate the limitations of the original 3D collision avoidance method and present the modifications on the algorithm. Second, we develop the velocity obstacle method to be capable of handling cube obstacles in 3D space. Third, a real flight test is conducted to verify the effectiveness of the proposed threedimensional velocity obstacle method.