• Journal of Positioning, Navigation, and Timing
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• v.10 no.1
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• pp.1-12
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• 2021

Due to the Global Navigation Satellite System (GNSS) modernization, the recently launched GNSS satellites transmit signals at various frequency bands of L1, L2 and L5. Considering the Korea Positioning System (KPS) signal and other GNSS augmentation signals in the future, there is a high probability of applying more complex communication techniques to the new GNSS signals. For the reason, GNSS receivers based on flexible Software Defined Radio (SDR) concept needs to be developed to evaluate various experimental communication techniques by accessing each signal processing module in detail. In this paper, we introduce a multi-constellation (GPS/Galileo/BeiDou) multi-band (L1/L2/L5) SDR by utilizing Ettus USRP N210. The signal reception module of the developed SDR includes down-conversion, analog-to-digital conversion, signal acquisition, and tracking. The down-conversion module is designed based on the super-heterodyne method fitted for MHz sampling. The signal acquisition module performs PRN code generation and FFT operation and the signal tracking module implements delay/phase/frequency locked loops only by software. In general, it is difficult to sample entire main lobe components of L5 band signals due to their higher chipping rate compared with L1 and L2 band signals. Experiment result shows that it is possible to acquire and track the under-sampled signals by the developed SDR.

• Journal of Korea Multimedia Society
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• v.14 no.1
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• pp.133-143
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• 2011

This paper proposes a mobile navigation system which haptically presents the way to go to visually impaired persons. In order to convey the tactile information to the visually impaired persons, we develop a new tactile module with a solenoid, a permanent magnet and an elastic spring. Furthermore, we suggest 2D vibration flow which originates from one point and gradually propagates to other points on a surface of the haptic navigation system. The tactile module and the vibration flow method are incorporated into the proposed haptic navigation system and they stimulate the user's finger pad and palm, respectively. We conduct experiments to investigate that the proposed navigation system haptically provides the direction to the users. From the experimental results, we verify that the proposed system can generate enough tactile sensation to guide the direction to go in real-time.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.10a
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• pp.117-118
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• 2012

As the technical standard of hydrographic data was transferred from S-57 to S-101, a standard system was set up for producing the next generation ENCs but also various maritime safety information. ECDIS that display a S-57 ENC and include a navigation support function, should be developed considering new standard. S-10X data and e-Nav information can be used in this system. In this study, an implementation mechanism of S-100 standard was analyzed for design of navigation support system based on S-100. From the results, it was designed as loading module of S-10X data, display module of SENC, navigation supporting module. Also, this study considered a next generation ENC, a bathymetric grid data, an electronic nautical publication as an input information.

• Journal of Astronomy and Space Sciences
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• v.25 no.2
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• pp.227-238
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• 2008

GNSS (Global Navigation Satellite System) Ground Station monitors navigation satellite signal, analyzes navigation result, and uploads correction information to satellite. GNSS Ground Station is considered as a main object for constructing GNSS infra-structure and applied in various fields. ETRI (Electronics and Telecommunications Research Institute) is developing Monitoring and Control subsystem, which is subsystem of GNSS Ground Station. Monitoring and Control subsystem acquires GPS and Galileo satellite signal and provides signal monitoring data to GNSS control center. In this paper, the configurations of GNSS Ground Station and Monitoring and Control subsystem are introduced and the preliminary design of Monitoring and Control subsystem is performed. Monitoring and Control subsystem consists of data acquisition module, data formatting and archiving module, data error correction module, navigation solution determination module, independent quality monitoring module, and system operation and maintenance module. The design process uses UML (Unified Modeling Language) method which is a standard for developing software and consists of use-case modeling, domain design, software structure design, and user interface structure design. The preliminary design of Monitoring and Control subsystem enhances operation capability of GNSS Ground Station and is used as basic material for detail design of Monitoring and Control subsystem.

• Journal of Navigation and Port Research
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• v.37 no.4
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• pp.391-400
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• 2013

Each country has recently established and operated so called Aids to Navigation(AtoN) AIS system collecting and transferring information on the sea state and AtoN's position. Korea has also decided to introduce the system and been establishing it. And it has already installed and operated this system in Incheon and Daesan. For the purpose of giving the national standards of AtoN AIS, this paper is to investigate the present states of AtoN AIS systems in the above two area and to suggest the improvement to the operation of AtoN AIS system. To make it, the paper deals with the international regulations of related AtoN AIS and the cases of foreign's AtoN AIS system installed and also investigates the operation states of the system, in five modules such as system management, system composition, information, function and cooperation. The followings are concluded; improving the inconsistency of system management, reducing operator's confusion caused by excessive display of AtoN AIS system, improving the problem of receiving unnecessary information, improving the functional problems caused by AIS communication inability and improving AtoN AIS information which is presently not used on board.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.4
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• pp.595-602
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• 2021

Marine accidents are mostly caused by medium and small ships, and are continuously increasing. In this paper, we propose an architecture of the speech synthesis based automatic safety navigation support service providing system for small ships that equiped onboard systems compared with vessels. The main purpose of the system is to prevent marine accidents by providing synthesized voice safety messages to nearby ships. The safety navigation support service is operated by connecting GPS and AIS to synthesize voice safety messages, automatically broadcast through VHF. Therefore, we developed a data processing module, a staged risk analysis module, a voice synthesis safety message generation module, and a VHF broadcasting equipment control module, which are components of the system. In addition, we conducted laboratory-level and sea-trial demonstration tests using the developed the system, which verified usefulness of the proposed service.

• Journal of Advanced Navigation Technology
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• v.18 no.4
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• pp.268-277
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• 2014

It is very important to correlate flight plan for safe and prompt ATC(air traffic control) operation. In this paper, we design CWP(controller working position) MRT(multi radar tracking) processing module to achieve improvement of overall ATC automation system's performance by minimizing network traffic overload when correlating MRT with flight plan. This implemented module can guarantee efficiency and safety of ATC automation system by applying distributed correlated manner, and reduce network usage by using encoded flight plan correlated MRT data format. We found that this module has 8.54~12.11% lower network usage and 8.37~11.27% higher network traffic fairness than the module using standalone manner.

• Journal of Ocean Engineering and Technology
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• v.27 no.3
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• pp.22-28
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• 2013

This paper suggests a navigation information display system that is based on augmented reality technology. A navigator always has to confirm the information from marine electronic navigation devices and then compare it with the view of targets outside the windows. This "head down" posture causes discomfort and sometimes near accidents such as collisions or missing objects, because he or she cannot keep an eye on the front view of the windows. Augmented reality can display both virtual and real information in a single display. Therefore, we attempted to adapt AR technology to assist navigators. To analyze the outside view of the bridge window, various computer image processing techniques are required because the sea surface has many noises that disturb computer image processing for object detection, such as waves, wakes, light reflection, and so on. In this study, we investigated an analysis module to extract navigational information from images that are captured by a CCTV camera, and we validated our prototype.

• Convergence Security Journal
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• v.19 no.2
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• pp.73-81
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• 2019

In this paper, we propose a user-dependent mid-point navigation system using a time weighted mid-point navigation algorithm and a user preference based mid-point neighborhood recommendation system. The proposed system consists of a mid-point navigation module for calculating an mid-point by applying a time weight of each user based on a departure point between users, and a search module for providing a search for a route to the calculated mid-point. In addition, based on the mid-point search result, it is possible to increase the utilization rate of users by including a place recommending function based on user's preference. Experimental results show that the proposed system can increase the efficiency of using by the user-dependent mid-point navigation and place recommendation function.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.10a
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• pp.53-54
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• 2015

The maritime industry is expanding at an alarming rate and as such there is a perpetual need to improve situation awareness in the maritime environment using new and emerging technology. Tracking is one of the numerous ways of enhancing situation awareness by providing information that may be useful to the operator. The tracking system described herein comprises determining existing states of own ship, state prediction and state compensation caused by random noise. The purpose of this paper is to analyze the process of tracking and develop a tracking algorithm by using ${\alpha}-{\beta}-{\gamma}$ tracking filter under a random noise or irregular motion for use in a warship. The algorithm involves initializing the input parameters of position, velocity and course. The actual positions are then computed for each time interval. In addition, a weighted difference of the observed and predicted position at the nth observation is added to the predicted position to obtain the smoothed position. This estimation is subsequently employed to determine the predicted position at (n+1). The smoothed values, predicted values and the observed values are used to compute the twice distance root mean square (2drms) error as a measure of accuracy of the tracking module.