Rendezvous Guidance Laws for Aerial Recovery using Mothership-Cable-Drogue System

This paper presents a comparison of prospective guidance laws for aerial recovery of UAVs using a Mothership-Cable-Drogue system. The guidance methods for rendezvous should simultaneously take the LOS distance, the LOS rate and the relative velocity between the UAV and the drogue to zero. Furthermore, the guidance laws should ensure the terminal alignment of the UAV along the longitudinal axis of the drogue. This alignment is quantified as a funnel shaped spatial region with its narrow end at the conical drogue. The paper essentially compares the two guidance laws, pure pursuit and trajectory shaping, on the basis of the entry of the UAV into this funnel. The comparison is presented in terms of the UAV conditions (position and heading) that lead to a rendezvous satisfying the terminal spatial constraints.