Abstract
This paper proposes a key feature for vision based automatic landing of a UAV: the addition to a given control law of the constraint that a given ground point be maintained in the camera field of view (FoV). This feature is an application case of an output constraint method recently developed and available for any nonlinear system. This method is based on an observation made for relative degree one systems, and extended iteratively to any nonlinear system. The landing aircraft application case considered in this article consists of the design of a control law for an aircraft to maintain a given ground point in the camera field of view for visual servoing purpose. Simulation results confirm the effectiveness of the approach.