• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.5
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• pp.638-645
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• 2020

The mast is the highest structure in a naval ship, and various communication and radar antennas are installed to achieve long-range communications and line of sight. The U.S. and European navy currently are adopting integrated mast to their new ships, as it can reduce the Radar Cross Section(RCS) of the new ships and thus improve survivability of the ship. In this paper, when other navies adopt integrated masts on new ships, types of antennas, according to the cases that the antennas are integrated on the integrated mast or not, are analyzed. Also the types of antennas and transmission techniques for the radio communication equipments of the Korean Navy are analyzed in various frequency bands. For adopting an integrated mast on Korean new ships, the effects of the ship RCS according to the types of antennas, the possibility of integration the antennas and the integrated mast and considerations were presented.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.2
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• pp.87-96
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• 2020

The multi function radar is searching target and tracking through resource management at the same time. Increasing resource allotment of track, if more targets and faster the renewal rate of track, lead to decreasing quota of searching resource in limited resource. When the resource of search are decreased, it becomes degrade searching performance such as revisit time, number of detecting chance and tracking etc. Degraded performance of search reduces guided missile defense probability in complex strategy such as ship self defense. In this paper, we developed a modeling and simulation (M&S) tool that uses own-ship model, radar model, target model and defense model for analysis of self defense in complex strategy. We analyzed influence of ship self defense in complex strategy according to various target environments and track performance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.1125-1129
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• 2005

In this study, for suggesting the development of GPS navigation in the naval vessels, the test of GPS error is conducted for analyzing the precision of GPS installed in the naval vessels. And the reliability and utilization of GPS are verified throughout interview and questionnaire with the workers in the naval vessels.

• Special Issue of the Society of Naval Architects of Korea
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• 2006.09a
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• pp.23-33
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• 2006

Generally wave buoy and visual observation are used to measure sea waves. But the wave buoy cannot be applicable for the ship moving in deep sea. So the visual observation has been used for it. But it has several defects and limitation related to environmental condition and observer. To overcome this problem, various wave measurement systems have been suggested. Recently, the wave measurement systems using nautical X-band radar have been developed and extended its application area. In this report, we introduce the wave measurement system, WaveFinder, developed by authors. The system was calibrated and verified with the measurement results of wave buoy. The system was adopted to measure wave condition during sea trials. The system will be a device to support safe navigation in ship's voyage.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.5
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• pp.571-576
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• 2015

This paper presents a comparative study of wave height estimation method that was used for signal to noise ratio and shadowing ratio based on X-band marine radar. If the signal to noise ratio, and is widely used as a method for estimating an wave height, a new method is presented for shadowing ratio. In the case of radar images used in this study it is measuring the data from the coast of Ulsan Jujeon, compared with marine meteorological information from the Meteorological Agency measured a light beacon. We compared the measured data for about 34 days, the typhoon was measured, incluidng a period in the East Sea, and verify the results for various distribution of wave height. For estimate wave height using a shadowing ratio analysis, it does not require calibration and real-time advantages of this part, coming confirmed the possibility of the measurement, the cause detection error for radar image was caused due to determine.

• ETRI Journal
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• v.41 no.6
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• pp.750-759
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• 2019

Presently, the extraction of hand-crafted features is still the dominant method in radar emitter recognition. To solve the complicated problems of selection and updation of empirical features, we present a novel automatic feature extraction structure based on deep learning. In particular, a convolutional neural network (CNN) is adopted to extract high-level abstract representations from the time-frequency images of emitter signals. Thus, the redundant process of designing discriminative features can be avoided. Furthermore, to address the performance degradation of a single platform, we propose the construction of an ensemble learning-based architecture for multi-platform fusion recognition. Experimental results indicate that the proposed algorithms are feasible and effective, and they outperform other typical feature extraction and fusion recognition methods in terms of accuracy. Moreover, the proposed structure could be extended to other prevalent ensemble learning alternatives.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.45 no.2
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• pp.12-19
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• 2022

Artificial intelligence is driving the Fourth Industrial Revolution and is in the spotlight as a general-purpose technology. As the data collection from the battlefield increases rapidly, the need to us artificial intelligence is increasing in the military, but it is still in its early stages. In order to identify maritime targets, Republic of Korea navy acquires images by ISAR(Inverse Synthetic Aperture Radar) of maritime patrol aircraft, and humans make out them. The radar image is displayed by synthesizing signals reflected from the target after radiating radar waves. In addition, day/night and all-weather observations are possible. In this study, an artificial intelligence is used to identify maritime targets based on radar images. Data of radar images of 24 maritime targets in Republic of Korea and North Korea acquired by ISAR were pre-processed, and an artificial intelligence algorithm(ResNet-50) was applied. The accuracy of maritime targets identification showed about 99%. Out of the 81 warship types, 75 types took less than 5 seconds, and 6 types took 15 to 163 seconds.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.117-120
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• 2008

In this paper, we developed the EM wave absorber for eliminating false images in collision-avoidance radar. First of all, we fabricated some samples in different composition ratio of $TiO_2$ and CPE. And the relative permittivities of samples are calculated from S-parameter of samples by using 1-port method. We designed and fabricated the EM wave absorber by using the calculated relative permittivity. As a result, the EM wave absorber with composition of $TiO_2$:CPE=70:30 wt% has thickness of 1.85 mm and absorption ability higher than 20 dB in the frequency range 76-77 GHz.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2017.11a
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• pp.103-105
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• 2017

e-Navigation, which is scheduled to be implemented in 2019 centered on IMO, is actively conducting researches worldwide and various marine systems are being developed. Ship INS will be integrated with various navigation systems such as RADAR, ECDIS, BAM, etc. in order to support e-navigation system, and there is a great need for integrated operation and management. In this research, introduce a research on the integration method of platform - based ship navigation equipment that can operate, expand, maintain and repair various ship systems efficiently.

• Journal of the Society of Naval Architects of Korea
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• v.37 no.4
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• pp.82-91
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• 2000

In this study, a numerical scheme based on physical optics method is developed to predict RCS of perfectly conducting body. The scheme is verified through the comparisons of numerical values of cylinder and sphere with analytical ones. It is also applied to compute RCS of a fast naval craft. Major reflection of this ship at threat angle of 0 degrees is found to be due to superstructure and stern part of main hull. In order to investigate the shaping effects on the ship. inclination angles of the stern of main hull and superstructure are set to 12 degrees. The RCS of the ship with shaping is proven to be much reduced in comparison with one without shaping.