• Journal of the Korean Institute of Navigation
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• v.20 no.3
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• pp.107-115
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• 1996

With the rapid advance of electronic equipments and the frequent, use of them, the electromagnetic environments including EMC or EMI problems are very complicated. The radiation of electromagnetic waves from electronic equipments has strictly been controlled by the authorities concerned from many years ago. Though it is the most proper to test EMI or EMC in the open area test site, we have used the anechoic chamber in place of the test site because of its various restrictions. To achieve the purpose, in this paper, the performances of a few anechoic chambers according to absorbing materials are analyzed for horizontal and vertical polarizations respectively. Furthermore, the calculated and the measured site attenuations in semi-anechoic chamber made with ferrite grid are compared. The obtained results are to be valuable for designing an anechoic chamber.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.11a
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• pp.209-210
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• 2019

This paper deals in the wireless communication module for a realization of maritime telemedicine system. In order to provide a maritime telemedicine service, we realized a digital electronic circuit for a visual communication and remote control system. In this work, we report the digital circuit structure, and communication method, etc.

• Journal of Institute of Control, Robotics and Systems
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• v.1 no.1
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• pp.43-49
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• 1995

본 논문에서는 초음파 센서와 시각 센서에서 얻은 전방향 센서 데이타를 이용하여 실내 이동 로봇용 국부 유도 항법을 위한 새로운 환경 모델링 방법을 제안한다. 그리고 이 두 종류의 센서 데이타에 포함된 불확실성을 주관적 지식과 퍼지 연산법을 사용하여 정량적으로 다룰 수 있는 센서 융합법을 제안한다. 이 방법을 사용하여, 로봇의 현재 위치와 목표 위치간의 기하학적 관계를 더욱 정확하게 얻을 수 있다. 실험 결과를 통하여 제안된 모델링과 센서 융합법이 실내 이동 로봇 항법에 효과적임을 보였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.06a
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• pp.80-81
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• 2011

Canada British Columbia 주의 Prince Rupert 와 Port Hardy(503km) 를 1주일에 2회 왕복하던 Queen of the North 호가 2006년 3월 22일 Gill Island 북쪽 해상에서 좌초되었다. 사고 후, 선박에 탑재된 Electronic Chart System(ECS)을 수거하여 선박의 항해자료를 회수키로하고, 2006년 6월 15일 해양탐사로봇을 이용하여 해저 약 453m 지점에 착저된 선박으로부터 ECS 컴퓨터를 수거하였고 Maker인 Transas사는 수거된 ECS의 Data를 복원하여 선주사에 재공하였다. 이에 따라 캐나다 교통안전국 (Transportation Safety Board of Canada)는 재현 결과물을 통하여 사고원인을 규명한 사건이다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.11a
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• pp.127-129
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• 2018

RadarBeacons are navigational equipment that helps the navigators avoid dangerous rocks, such as heavy fog, nighttime, etc. when ships operate, or when visibility is bad. The existing antenna was researching the development of the advanced radar eacon (Enhanced Radar Beacon) for improving the development of the next generation racon with the AIS (Automatic Identification System) function.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1997.10a
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• pp.43-50
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• 1997

The Singapore Strait is one of the world's busiest waterways used by international shipping Coupled with this, the Port of Singapore is the world's busiest port in terms of shipping and cargo tonnage and the second busiest container port. Navigational safety is Singapore's concern and we are convinced that the ECDIS is the key to further enhancing navigational safety in the Singapore Strait and the port waters of Singapore. We have initiated the production of Electronic Navigational Chart data and invested in infrastructural supporting facilities such as DGPS brodcast service for use with ECDIS as well as other maritime systems.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.63-66
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• 2006

This paper proposes an ultrasonic location system based on the spread spectrum principle. Compared with the existing ultrasonic location systems, the proposed system combines the spread spectrum and amplitude modulation principles. As a result, the proposed ultrasonic location system is advantageous in that it can improve positioning accuracy and detection sensitivity by the spread spectrum principle, it simplifies transmitter and receiver circuits by the amplitude modulation, and it is easy to upgrade its performance by the software functionalities. The advantages and performance of the proposed location system are demonstrated by experiments.

• Journal of the Korean Institute of Navigation
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• v.21 no.4
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• pp.29-38
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• 1997

Because of the result of a large use of electronic equipments, the occupation density of microwave frequency band is highly increased, and electromagnetic environment is getting more seriously bad. It is sometimes reported that electronic machines are not normally operated on account of the influence of undesired electromagnetic wave, which often gives fatal blow to even human life and thus becomes serious social problems. OATS(Open Area Test Site) is principally used to measure EMI or examine elelctromagnetic emission. Because of various restrictions we often build semi-anechoic chamber which has the function of OATS to measure EMI or EMS other than OATS. If the difference of the site attenuation between semi-anechoic chamber and OATS is within ${\pm}3dB$, the semi-anechoic chamber is recognized as adequate facility to measure EMI or EMS. Accordingly authors evaluate and analyze site attenuation due to absorbent materials, polarization, mutual coupling effects, etc. The calculated and the measured site attenuation in semi-anechoic chamber are compared. As a result good agreement is obtained.

• Journal of Advanced Navigation Technology
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• v.6 no.4
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• pp.312-317
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• 2002

This paper presents a graphical design method for a low noise amplifier using the match circles plotted in the ${\Gamma}_{IN}$ plane on the smith chart. Each circle would be useful for reducing some trial and error efforts resulting from making a trade-off for an optimized performance of a single stage amplifier. A design example is presented to illustrate the design procedure.

• Journal of Positioning, Navigation, and Timing
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• v.9 no.4
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• pp.379-385
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• 2020

The satellite employs an adaptive beamformer to efficiently detect various signals and to suppress multiple interference signals, simultaneously. Although the adaptive beamforming satellite system needs Angle-of-Arrival (AOA) information of the desired signal, it is difficult to estimate the signal AOAs on the satellite environment. However, the AOA estimation on the ground control tower is more efficient and accurate comparing to the satellite environment. In this paper, we propose an adaptive beamforming satellite system based on the signal location information on the ground, consisting on an angle estimator, an adaptive beamformer, and signal processing & D/B unit. The ground control tower estimates the accurate location of the signal source, and it sends the estimated coordinates of the desired signal to the satellite. The angle estimator mounted on the satellite calculates the desired signal AOA, based on the signal location information transmitted from the ground control center. The satellite beamformer detects the desired signal and suppresses unwanted signals based on the signal AOA calculated by the angle estimator. We provide computer simulation results to present the performance of the proposed satellite adaptive beamforming system based on the signal location information.