“…x _ y _ z T = quadrotor translational velocities in I , m∕s ξ x y z T = quadrotor positions in I , m ξ s x s y s z s T = ship positions in I , m τ τ ϕ τ θ τ ψ T = torques along quadrotor body axes, N ⋅ m χ mx , χ my , χ mz = state vectors of the reference models for Δx, Δy, and Δz dynamics, respectively χ mz1 = first component of the vector χ mz , m Ω p q r T = quadrotor rotational velocities in Q, deg ∕s ω w , ω E = sea wave and encounter wave frequencies, respectively, rad∕s ω 0R , ω 0ACC = peak frequencies of the ship heave motion and ship heave acceleration spectrums, respectively, rad∕s I. Introduction T HE research in the automation of unmanned aerial vehicles (UAVs) has evolved rapidly over the past decades, which is driven by their various applications ranging from military combat to civilian infrastructure inspection [1,2]. Moreover, compared to manned aircrafts, the UAVs are more suitable and expandable for dull, dirty, and dangerous missions [3].…”