Adaptive three-dimensional guidance of flying vehicle at fixed point with specified approach direction

The problem of steering a flying vehicle to a fixed point with a specified orientation of the terminal velocity is studied. The method is based on a modification of the well-known proportional navigation method in which the navigation parameter relating the angular rotation velocities of the line of sight and the velocity vector is chosen based on the current characteristics of the trajectory. The adaptivity of the method is ensured by the periodic correction of this parameter. For three-dimensional (3D) trajectories, a combination of two motions-(a) guidance in the plane formed by the given direction of the terminal velocity and the current state of the vehicle (in this plane, the specified terminal velocity direction is ensured using the modified proportional navigation) and (b) control in the orthogonal plane based on the classical proportional navigation with a fixed navigation parameter to minimize the rotation of the guidance plane. The proposed method does not require onboard trajectory prediction but forms the control using the current navigation data. Examples of various types of 3D trajectories of a gliding vehicle with a high lift-to-drag ratio are discussed.