Design of a Horizontal Guidance Algorithm for Optimal Crossing of Trajectory Legs

In this article a horizontal guidance algorithm for an unmanned air vehicle is proposed، based on trajectory waypoints and legs between them. Design is done in two phases. For straight legs، a line following algorithm is designed، with consideration of autopilot dynamics، and for turn from active leg to next one، a turn guidance algorithm is proposed. Turn guidance algorithm is designed in two steps. At the first step، a desired trajectory is selected and then an algorithm is proposed to shape the trajectory according to the desired trajectory. Also with consideration of maximum lateral acceleration of the UAV and no jumping in lateral acceleration command at the beginning of turning phase، start and end point of the turn is determined to minimize the turn trajectory from legs.