• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.6
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• pp.745-751
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• 2013

In naval gun firing, firing accuracy comes from the combination of each component's accuracy in CFCS (Command and Fire Control System) like tracking sensors and gun. Generally, battery alignment is done to correct the error between gun and tracking sensor by using boresight telescope on harbor and sea. But normally, the battery alignment can compensate only the static alignment error and ignore dynamic alignment error which is caused by own ship movement. There was no research on this dynamic alignment error until now. We propose a new way to analyze dynamic arrangement error by using image of boresight telescope. In case of the dynamic alignment error was due to time delay of own ship attitude information, we propose the way to compensate it.

• Journal of the Society of Naval Architects of Korea
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• v.60 no.4
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• pp.248-255
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• 2023

In order to implement the autonomous navigation function, it is essential to track an object within a certain radius of the ship's route. This paper proposes the Multiple Probabilistic Data Association Filter (MPDAF), which can track multiple ships by extending Probabilistic Data Association Filter (PDAF), an existing single object tracking algorithm, using radar data obtained from real marine environments. The proposed MPDAF algorithm was developed to address the problem of tracking multiple objects in a complex environment where there can be significant uncertainty in the number and identification of objects to be tracked. Using real-world radar data provided by the German aerospace center (DLR), it has been verified that the proposed algorithm can track a large number of objects with a small position error.

• Journal of Advanced Navigation Technology
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• v.14 no.6
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• pp.783-790
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• 2010

For safety navigation of ships at sea, ships monitor their location obtained from Global Positioning Satellite System (GNSS). In this study, we computed near-real-time positions of a ship at sea using GPS Precise Point Positioning (PPP) technique and analyzed precision of the near-real-time positions. We conducted ship borne GPS observations in the south sea of Korea. To process the GPS data using PPP technique, GIPSY-OASIS (GPS Inferred Positioning System-Orbit Analysis and Simulation Software) developed by the Jet Propulsion Laboratory was used. Antenna phase center variations, ocean tidal loading displacements, and azimuthal gradients of the atmosphere were corrected or estimated as standard procedures of high-precision GIPSY-OASIS data processing. As a result, the precisions of near-real-time positions was ~1cm.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.3
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• pp.259-265
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• 2015

It is clearly understood that e-navigation is beneficial to prevent collision and grounding of ships. The purpose of this study is to define and present a future ship operation system under the e-navigation environment in order to provide clear direction for the design of Korean e-navigation system. The future ship operation system consists of shipboard navigational system, shore supporting system and maritime communication system. To achieve the objectives of this study, the ship operation system was discussed separately into SOLAS ships and non-SOLAS ships in this study. In SOLAS ships, mariners become a system manager, choosing system presets, interpreting system output, and monitoring vessel response. In small ships and fishing vessels, mariners may enjoy their navigation by using the automatic tracking of ship's position on the portable electronic chart display. The improved bridge design, integrated and harmonized navigational system and single window reporting will reduce significantly the administrative and physical workload of mariners. Mariners can concentrate their attention more on navigational duty under the e-navigation environment. To build an effective Korean e-navigation system, the essential navigational functions and e-navigation services for small ships and fishing vessels must be identified and developed taking into account user needs.

• The Journal of the Acoustical Society of Korea
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• v.17 no.3E
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• pp.22-26
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• 1998

This paper proposes a simple method to measure system's performance in target tracking problems. Essentially employing the Cramer-Rao Lower Bound (CRLB) on tracking accuracy, an algorithm of predicting system's performance under various scenarios is developed. The input data is a collection of measurements over tim from sensors embedded in Gaussian noise. The target of interest may not maneuver over the processing time interval while the own ship observing platform may maneuver in an arbitrary fashion. The proposed approach is demonstrated and discussed through simulation results.

• Journal of Aerospace System Engineering
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• v.10 no.3
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• pp.44-51
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• 2016

This paper describes the operational concept of the Aegis ship's missile defense. Recently, North Korea conducted a fourth nuclear-weapon test that involved the launch of a long-range missile and the underwater launch of an SLBM. The ground-based BMD (Ballistic Missile Defense) system is very limited for the SLBM of a miniaturized nuclear warhead; therefore, it is necessary to build a reliable sea-based missile-defense system. The ROK Navy has, however, only utilized the Aegis ship that is designed with a search-and-tracking sensor but is without a ballistic-missile interception capability. Given this information, this work focuses on the operational concept of the Aegis BMD by comparing the BMD capabilities of the ROK with those of the U.S.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.10
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• pp.1318-1326
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• 2014

The purpose of a tracking control system is to track a moving target and to find the exact information of the target. If the platform of the tracking control system is equipped on a moving vehicle such as a ship, the tracking control system will treat even the additional platform motion. In order to avoid the complexity comprising the tracking control system, a process to treat the platform motion, named stabilizing system, must be separated from the tracking control system. In this paper, a method to comprise an attitude control system for the platform stabilization is proposed using an adaptive fuzzy control which is applicable to the system with structural and parametric uncertainty. The suggested adaptive fuzzy control algorithm is the 2nd/1st-type indirect adaptive fuzzy control algorithm using the advantages of 1st-type and 2nd-type indirect adaptive fuzzy control algorithm. Several experiments using the implemented stabilizing system are executed for verifying the effectiveness of the suggested method.

• Journal of Ocean Engineering and Technology
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• v.24 no.2
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• pp.10-17
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• 2010

Conventionally, because it is difficult to control a ship in shallow water and because attempting to do so creates unwanted environmental effects, maneuvering ships in the harbor area for berthing is usually done with the assistance of tugboats. In this paper, we propose a new method for berthing ships automatically by using bow and stern thrusters. Specifically, a steering motion model of a ship is considered, and parameters in the equation are evaluated by the system identification technique. An optimal controller based on observations was designed from the linearization of the non-linear ship motion in the horizontal plane. It is used to reduce the uncertainty about the ship's dynamics and reduce measurement requirements. The performance of the controller was also analyzed for its robustness relative to avoiding disturbing the environment due to winds, currents, and wave-drift forces. Experiments were conducted to estimate the potential for identifying result and the design of the controller. Specifically, in this paper, the system modeling and tracking control approach are discussed based on a two-degree-of-freedom (2DOF) servo-system design.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.151-156
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• 2006

Accurate vessel traffic observation is indispensable to carry out vessel traffic management, design of vessel traffic route, planning of port construction, etc. In order to observe the vessel traffic accurately without many efforts such as the use of a ship or car equipped with special radar observation system and the preparation of observation staff, the authors have been developing completely automated remote radar/AIS network system covering the main traffic area in Tokyo Bay. The composite radar image observed at Yokosuka and Kawasaki radar stations with AIS information can be seen on web site of Internet. In addition to the development of radar/AIS observation system, the software to analyze observed vessel traffic flow has been developed. This software has various functions such as automatic tracking of ship's positions, automatic estimation of ship's size, automatic integration of radar image and AIS data, animation of ships' movements, extraction of dangerous ship encounters, etc. The configuration and functions of the developed remote radar/AIS network system are shown first in this paper. Then various functions of the software to analyze vessel traffic are introduced, and some analyzed results on the vessel traffic in Tokyo Bay are described demonstrating the effectiveness of the developed system.

• Journal of the Korean Society of Marine Environment & Safety
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• v.6 no.1
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• pp.1-9
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• 2000

The paper describes system design of next-generation Ship Simulator using Virtual Reality (VRSS), well known as human-computer interaction. VRSS system is required to have special condition that comprises multiple user participants such as captain, officer, pilot, and quartermaster. To cope with that condition, core technologies were explored and proposed multi-networking system with broker server. The evaluation of the proposed system was done with PC-based immersion-type VR device, constituted with HMD (Head Mounted Display), Head Tracking Sensor, Puck, Headphone, and Microphone. Using the VR device, assessment test was carried out in a virtual bridge with 3D objects, which are created by VRML (Virtual Reality Model Language) program. As results of tests, it is shown that the cybernetic 3D objects were act as if real things in a real ship's bridge. Therefore, interesting interaction with participants can be obtained in the system, Thus, we found that the proposed system architecture can be applicable to VRSS system construction.