Launch and recovery helicopter wind envelope for a ship type was determined as the first step to the helicopter qualification program. Flight deck velocities data were obtained by means of a two components laser Doppler anemometer testing a 1/50 model in the wind tunnel stream. Full-scale flight deck measurements were obtained on board the ship using a sonic anemometer. Wind tunnel and full-sca...

Of all the flight modes of unmanned aerial vehicles (UAVs), the landing approach and the landing itself are the most difficult and dangerous ones. To perform an automatic landing on a ship deck using a computer vision system (CVS), a UAV must analyze the visual landing markers located on the deck. When the UAV is about to start landing, these markers must be clearly visible and discernible. The...

Local Vibrations represent one of the most critical parameters for the comfort evaluation on board of the ship. Normally a limit value of vibration is defined in the ship specification and the shipyard has the responsibility to assure that the specified values are not exceeded. Depending mainly on the extension, vibration phenomena could be divided in Global Hull vibrations and local vibrations...

This paper presents a novel and practical procedure for estimating the mean deck height to assist in automatic landing operations of a Rotorcraft Unmanned Aerial Vehicle (RUAV) in harsh sea environments. A modified Prony Analysis (PA) procedure is outlined to deal with real-time observations of deck displacement, which involves developing an appropriate dynamic model to approach real deck motio...

We investigated the levels of radio frequency electromagnetic fields (RF EMFs) emitted from marine ship transmitters. In this study, we recorded the radio frequency (RF) electric field (EF) levels emitted from transmitters from a marine vessel focusing on the areas normally occupied by crew members and passengers. Previous studies considered radiation hazard safety assessment for marine vessels...

Computational fluid dynamics (CFD) simulations of ship airwakes are discussed in this article. CFD is used to simulate the airwakes of landing helicopter assault (LHA) and landing platform dock-17 (LPD-17) classes of ships. The focus is on capturing the massively separated flow from sharp edges of blunt bodies, while ignoring the viscous effects. A parallel, finitevolume flow solver is used wit...

Currently, the speed at which materials can be transferred between ships at sea is limited by sea conditions. Rough sea conditions cause the payload to swing making load transfer difficult and timeconsuming. The objective of this research is to develop a real-time, command compensating control for reducing sea state induced payload swing for shipboard robotic cranes. The future use of this cont...

This paper presents a novel and feasible prediction procedure for ship motion in the presence of uncertain tendency of ship motion dynamic variations and stochastic sea state disturbances. An appropriate model aiming to feature the characteristics of the dynamic relationship between an observer and a ship deck is constructed, from which an initial algorithm is implemented. The optimal system or...

This paper examines some of the challenges that must be overcome if future aerial delivery systems are to have the capability to land on the flight deck of a ship underway. The unique aspects of trajectory planning for landing on a ship’s flight deck are first examined, followed by formulation of the position estimation problem for a moving target. Some preliminary investigations into character...

This article presents a novel recovery method for fixed-wing Unmanned Aerial Vehicles (UAVs), aimed at enabling operations from marine vessels. Instead of using the conventional method of using a fixed net on the ship deck, we propose to suspend a net under two cooperative multirotor UAVs. While keeping their relative formation, the multirotor UAVs are able to intercept the incoming fixed-wing ...