Yun-Ja Yoo

Arrayed GPS-buoys wave observation system

Since the period of the long period gravity wave is so long and its amplitude is relatively small, the accurate measurement by the conventional technique was often so difficult. At 2002 Techno-Ocean conference, we had proposed the wave direction finding system using the GPS buoy array using the multiple signal classification method for the wave signal analysis, and it was verified practically enough in the simulation test. After that conference, we had four experiments in order to prove the useful validity of our proposed system. We describe the method and some results of our three experiments and show the excellent accuracy to estimate wave directions.

Evaluation Test Result on Wave Direction Measurement Using GPS Buoy

In this paper, we apply the velocity integration method to measure a wave direction using buoys. A prototype system of the wave direction measurement with GPS buoys is proposed, and one simple observation method about wave direction is shown. Next, one test to evaluate this proposed system is described. Buoys equipped with GPS were moored in the observational sea area. As 3D movements of the buoys depend on the movement of seawater particles, we use the velocity integration method to get the precise velocity information of the buoys and apply the velocity to estimate the position of the buoys. As the test result, we can find the precise and reliable wave direction according to the horizontal displacement of the buoys with the 3D buoy movement analysis.

Experimental Results of Ship's Maneuvering Test Using GPS

Kinematic GPS provides quite good accuracy of position in cm level. Though K-GPS assures high precision measurement in cm level on the basis of an...

Simultaneous Measurement of Waves Outside and Inside Harbor and 3-D Movements of Moored Vessel

In order to solve various problems induced by the long period gravity wave and to reveal the characteristics of it, the wave measurement system of arrayed buoy equipped with kinematic GPS (K-GPS) was used. Two arrayed GPS buoys were located outside and inside harbor, also three GPS receivers were set on the moored vessel, measured 3D movement of them simultaneously, and six motion elements (surge, sway, heave, roll, pitch, yaw) were measured by three GPS receivers on the vessel. Also a wave direction was measured by the arrayed GPS buoys, and then estimated by means of the MUSIC (Multiple Signal Classification) method precisely. From the results, we could reveal the characteristics of the long period gravity wave, might solve the problems.

A Study on Wave Observation System with GPS Arrayed Buoys by using MUSIC Method

The long-period gravity wave, the wave period from some ten seconds to some minutes, induces not only the big sway of a ship moored and berthed in the harbor due to the horizontal long-distance motion of a water but also strong exfoliated flow and vortices near the harbor entrance. They muse serious problems on the safety navigation of vessels entering and leaving the harbor, but this gravity wave has not been searched sufficiently yet. Then it is quite important to reveal the characteristics of this long-period gravity wave ana to solve various problems induced by this wave. The long-period gravity wave measurement system with arrayed buoys installed the kinematic GPS was already proposed, which provides the precise propagating direction of the long-period gravity wave. In this paper, the observation results of the wave measurement system are shown by the MUSIC method And the propagating wave direction was estimated precisely enough in comparison with other results used other method.

Conceptual Design of Navigation Safety Module for S2 Service Operation of the Korean e-Navigation System

IMO introduced e-Navigation concept to improve the efficiency of ship operation, port operation, and ship navigation technology. IMO proposed sixteen MSPs (Maritime Service Portfolio) applicable to the ships and onshore in case of e-Navigation implementation. In order to meet the demands of the international society, the system implementation work for the Korean e-Navigation has been specified. The Korean e-Navigation system has five service categories: the S2 service category, which is a ship anomaly monitoring service, is a service that classifies emergency levels according to the degree of abnormal condition when a ship has an abnormality in ship operation, and provides guidance for emergency situations. The navigation safety module is a sub-module of the S2 service that determines the emergency level in case of navigation equipment malfunctioning, engine or steering gear failure during navigation. It provides emergency response guidance based on emergency level to the abnormal ship. If an abnormal condition occurs during the ship operation, first, the ship shall determine the emergency level, according to the degree of abnormality of the ship. Second, an emergency response guidance is generated based on the determined emergency level, and the guidance is transmitted to the ship, which helps the navigators prevent accidents and not to spread. In this study, the operational concept for the implementation of the Korean e-Navigation system is designed and the concept is focused on the navigation safety module of S2 service.