Helicopter GNC system for autonomous landing by using a tether in a GPS denied scenario

This paper presents a Guidance, Navigation and Control (GNC) system for the autonomous landing of a Remotely Piloted Aircraft Helicopter (RPAS) in a GPS-denied scenario by using a tether in the landing. A new control and sensor fusion strategy has been designed for landing accurately by means of relative position and velocity commands. The system uses on-board the RPAS a device with a cardan joint providing the angles between the tether and the helicopter frame and a force sensor giving the tension of the tether.