• Title/Summary/Keyword: 항공 통신

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Integrated Ray Tracing Model for In-Orbit Optical Performance Simulation for GOCI (통합적 광추적 모델에 의한 해양탑재체 GOCI의 궤도 상 광학 성능 검증)

  • Ham, Seon-Jeong;Lee, Jae-Min;Kim, Seong-Hui;Yun, Hyeong-Sik;Gang, Geum-Sil;Myeong, Hwan-Chun;Kim, Seok-Hwan
    • Journal of Satellite, Information and Communications
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    • v.1 no.2
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    • pp.1-7
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    • 2006
  • GOCi (Geostationary Ocean Color Imager) is one of the COMS payloads that KARI is currently developing and scheduled to be in operation from around 2008. Its primary objective is to monitor the Korean coastal water environmental condition. We report the current progress in development of the integrated optical model as one of the key analysis tools for the GOCI in-orbit performance verification. The model includes the Sun as the emitting light source. The curved Earth surface section of 2500 km x 2500 km includingthe Korean peninsular os defined as a Lambertian scattering surface consisted of land and sea surface. From its geostationary orbit, the GOCI optical system observes the reflected light from the surfaces with varying reflectance representing the changes in its environmental conditions. The optical ray tracing technique was used to demonstrate the GOCI in-orbit performances such as red tide detection. The computational concept, simulation results and its implications to the on-going development of GOCI are presented.

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Analysis Results in Technological Trends of Military Small Giant Venture Tech-Fi Net via Social Network Analysis (사회연결망 분석을 이용한 국방 강소벤처 Tech-Fi Net 기술동향 분석)

  • Park, Jae Woo;Lee, Il Ro;Kwon, Jae Wook;Byun, Kisik;Cho, Sung-Yong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.12
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    • pp.444-455
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    • 2019
  • The purpose of this research was to analyze technological trends of 「Military Small Giant Venture Tech-Fi Net」 from Defense Technology Information Service via social network analysis. 「Military Small Giant Venture Tech-Fi Net」, which was constituted for their fine technology for application to the military field, registered 847 technologies of 388 companies. In this research, we analyzed 847 technologies for the relations between "Military System" and "Military Technology Category" via centrality measurement, one of the social network analysis methods. The results indicate that the major technologies of domestic military small giant venture companies were "Sensor" and "ICT" for "C4I System" and "Surveillance and Reconnaissance System" and "Platform/Structure" for "Land System", "Aeronautical System" and "Naval Sea System". In contrast, we recognized inadequate technologies, such as "Propellant" and "Material" for "Missile and Ammunition system" and "Sensor" and "ICT" for "Defense System", We hope that our results and method will be conducive to the technological development of Small Giant Venture companies.

Beginning of the Meteorological Satellite: The First Meteorological Satellite TIROS (기상위성의 태동: 최초의 기상위성 TIROS)

  • Ahn, Myoung-Hwan
    • Atmosphere
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    • v.22 no.4
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    • pp.489-497
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    • 2012
  • Recently released a top secret document explicitly shows that the early development plan for an earth observation satellite in the USA has a hidden and more important purpose for a concept of 'free space' than the scientific purpose. At that time, the hidden and secret concept imbedded within the early space development plan prevail other national policies of the USA government for purpose of the national security. Under these circumstances, it is quite reasonable to accept a possibility that the meteorological satellites which play a key role in the every area of meteorology and climatology was also born for the hidden purposes. Even it is so, it is quite amazing that the first meteorological satellite is launched in the USA despite of the facts that the major users of the meteorological satellites were not very enthusiastic with the meteorological satellite and the program was not started as a formal meteorological satellite project. This was only possible because of the external socio-political impact caused by the successful launch of the Russian Sputnik satellite and a few key policy developers who favored the meteorological satellite program. It is also interesting to note that the beginning of the first Korean meteorological satellite program was initiated by a similar socio-political influence occurred by the launch of a North Korean satellite.

Outer Space Activities and an Observation of Related Laws of Korea (국내 우주활동과 관련법 소고)

  • Park, Won-Hwa
    • The Korean Journal of Air & Space Law and Policy
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    • v.24 no.2
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    • pp.163-186
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    • 2009
  • The missile technology and its development in south Korea have been restrained to the limit of 180 km by America which instead provided to Korea with security protection. In the same vein, America pressured South Korea to abort its nuclear weapons program so as to prevent another possible military encounter that can easily develop into a war between South and North Korea. This restraint was a bit relaxed when South Korea joined the Missile Technology Control Regime (MTCR) in 2001 whereby the limit was 300 km. The situation of South Korea is in much contrast with its neighbor, North Korea, which has fired Taepo Dong 1 and Taepo Dong 2 to put its alleged satellite respectively into the Earth orbit. The range of this rocket believed to be reaching more than 5,500 km, a range of the intercontinental ballistic missile, without any rein. South Korea that has just geared its full powers for its outer space industry, with the current space projects of putting its satellites into the low Earth orbit, will in future put its satellite into the geostationary orbit, 36,000 km above the Earth. To do so, such restraint had better be resolved. Korean space industry, as it is alike in other countries, started with putting and manufacturing sounding rockets, producing satellites but relying on foreign launching facilities, and learning launching capacities. Experiencing three time launchings of KITSAT, the current satellite projects of Korea are undertaken as follows: - Koreasat - STSAT - Komsat - MBSAT - COMS (Communication, Ocean, and Meteorological Satellite) Koreans waked up to the things of outer space in 2008 with the first Korean astronaut Li So-yeon, a lady bio systems engineer. Although the first Korean made rocket in cooperation with a Russian company to fire last August 2009 was a failure, it should be considered as an inevitable process for future endeavors. There are currently three outer space related laws of Korea: Aerospace Industry Development Promotion Act 1987, Outer Space Development Promotions Act 2005, and Space Damage Compensation Act 2008. The first two stemming from the two different ministries are, however, overlapping in many aspects and have some shortcomings to be improved.

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Cavitation damage characteristics in seawater of electroless nickel plated gray cast iron (무전해 니켈 도금된 회주철의 해수 내 캐비테이션-침식 손상 특성)

  • Park, Il-Cho;Kim, Seong-Jong
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2016.11a
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    • pp.142-142
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    • 2016
  • 무전해 니켈 도금은 산업기계 부품, 자동차 부품, 항공 및 전자 통신 부품 등에 이르기까지 산업 전반에서 폭넓게 사용되고 있다. 이는 무전해 니켈 도금 층이 우수한 균일성, 내마멸성, 내식성 등을 지녀 관련 연구가 지속적으로 활발하게 진행되어 왔기 때문이다. 특히, 최근에 이르기까지 도금 층이 얇고, 우수한 내마멸성 및 낮은 마찰계수를 활용한 무전해 니켈 도금은 산업현장에서 기계 부품들의 수명을 연장시키고, 그 성능을 개선시키는데 용이하게 적용되고 있다. 본 연구에서는 이와 같이 무전해 니켈 도금 층의 우수한 특성을 활용하여 해수 부식과 캐비테이션-침식 복합 환경 하에 놓여 있는 금속 재료의 손상을 방지하고자 하였다. 이는 선박의 경우 최근 고속화, 대형화 추세에 따라 부품의 내구성 향상과 연비 효율성이 더욱 강조되고 있으며, 그에 따라 해수 속에서 고속 회전으로 더욱 가혹해진 캐비테이션 침식-부식 환경하에 놓인 선박의 프로펠러, 펌프 임펠러 및 케이싱 등의 금속재료 자체를 보호할 수 있는 고성능 재료의 개발이 요구되고 있기 때문이다. 또한 해양환경 하에서 무전해 니켈 도금 층에 대한 캐비테이션 침식 손상에 대한 연구는 미비한 실정이다. 본 연구에서는 회주철 표면에 무전해 니켈 도금을 실시하여 캐비테이션 침식 손상을 방지하고자 하였다. 무전해 니켈 도금을 실시하기 전 도금 층을 균일하게 형성하기 위해 샌드 페이퍼 #1200까지 연마 후 알칼리 탈지 실시하고, 산세(10% HCl)와 수세를 순차적으로 실시하여 전처리하였다. 이후 무전해 니켈 도금은 황산니켈, 차아인산나트륨, 구연산, 아세트산나트륨 그리고 미량의 질산납으로 구성된 도금욕에서 pH 4-6, $80-90^{\circ}C$의 조건으로 실시하였으며, pH는 NaOH를 이용하여 조정하였다. 이렇게 제작된 무전해 니켈 도금 층에 대하여 천연 해수 속에서 ASTM-G32 규정에 의거한 캐비테이션 침식실험을 통해 내구성을 평가하였다. 캐비테이션 실험 후에는 무게 감소량, 표면 손상깊이, 침식 손상 경향 등을 종합적으로 분석 비교하였다. 그 결과, 회주철에 대하여 무전해 니켈 도금을 실시할 경우 현저한 캐비테이션-침식 저항성 향상이 관찰되었다.

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Integrated Air Traffic Simulations of Manned and Remotely Piloted Aircraft (유무인항공기 통합 시뮬레이션 연구)

  • Oh, Hyeju;Park, Bae-Seon;Choi, Keeyoung;Lee, Hak-Tae;Jung, Hyun-Tae;Moon, Woo-Choon
    • Journal of Advanced Navigation Technology
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    • v.19 no.6
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    • pp.492-498
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    • 2015
  • With the rapid growth of technologies and demand of remotely piloted aircraft systems (RPASs), integration of such systems into the existing airspace is becoming an issue in many countries. To assess the impact of integrated operations of manned and remotely piloted aircraft (RPA), it is necessary to perform Human-in-The-Loop (HiTL) simulations of likely situations with an integrated simulation system. This paper defines several operational concepts for the integrated simulation. Several probable scenarios were developed including a traffic pattern at a small airport and an altitude maneuver at a route crossing. HiTL simulations were performed according to the developed scenarios. The simulation results are analyzed focusing on the impacts of different communication, safety, performance, and human machine interface (HMI) characteristics of RPA.

The Design and Performance Analysis of Physical Layer for VDL Mode-2 (VDL Mode-2 물리 계층 설계 및 성능 분석)

  • Choi, Jun-Su;Lee, Han-Seong;Kim, Tae-Sik;Kim, In-Kyu;Kim, Hyoun-Kyoung
    • Journal of Advanced Navigation Technology
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    • v.11 no.1
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    • pp.17-23
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    • 2007
  • This paper, describes the VDR physical layer design in VDL Mode-2 in order to meet the requirements of International standards. VDR's frequency band is 117.975~137MHz, and CSMA(Carrier Sense Multiple Access), D8PSK(Differential Eight Phase Shift Keyed), 25KHz's channel bandwidth use. The analysis of the isolated channel from near channels, sensitivity of the receiver, dynamic range of the receiver, linear of the transmitter and energy of spurious for linear and non-linear simulation as a requirement condition of performance of VDR and teaches the course of design. The transmitting power level should be lower than 5dB from Po1dB point and the selected IF frequency is 45MHz to suppress the spurious signals. The receiver designed has 4.5dB of Noise figure, 27.52dB of Es/No, Mixer isolation up to 30dB, IIP3 power of LNA up to +10dBm to minimize the intermodulation.

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Design and Implementation of Mobile Network Based Long-Range UAV Operational System for Multiple Clients (모바일 네트워크를 이용한 복수의 클라이언트용 무인항공기 원거리 운용 시스템 설계 및 구현)

  • Park, Seong-hyeon;Song, Joon-beom;Roh, Min-shik;Song, Woo-jin;Kang, Beom-soo
    • Journal of Advanced Navigation Technology
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    • v.19 no.3
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    • pp.217-223
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    • 2015
  • This paper describes the design and implementation of a network system for UAV for multiple clients that enables long-range operation based on a commercial mobile network. A prototype data modem is developed with a commercial embedded M2M module in order to provide an access to the mobile network. A central server with a database is constructed to record all of real-time flight and video data and communicate with a ground control system. A GCS is developed for the central control, the single UAV and the smart phone version to be used for different purposes. Performance tests were progressed for data delay, video frame rate and state of clients. Flight tests were also performed to verify the reliability of the modem with respect to altitude.

Study on Expansion of Cooperation Opportunities according to FTA between Korea and Israel (한-이스라엘 간 FTA 체결에 따른 협력기회 확대 연구)

  • Yoon, Jon-Mo
    • The Journal of the Korea Contents Association
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    • v.20 no.9
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    • pp.249-260
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    • 2020
  • This research examined Israel's economic trends, trades, and cooperation with Korea prior to the entry into force of the Free Trade Agreement (FTA) between Korea and Israel. Also, this research assessed opportunities and ways to expand the above more easily. Israel has a high level of technology in basic materials and information technology (IT). Meanwhile, Korea mainly exports automobiles and wireless communication equipment to Israel and imports semiconductor-related equipment and aviation components from Israel. Moreover, since the two countries signed a trade agreement in August 2019, they expect to expand trade with each other. As such, in order to promote multilateral trade and cooperation between the two countries, it is necessary to expand joint development opportunities through mutual collaboration on basic industries and smart mobility that Korea is in need. Further, Korean construction and materials companies related to the SOC industry in Israel should accelerate their local advances. In addition, more of the governmental support should be provided to foster regional experts and to offer various information to the companies entering the country.

Suggestion on the SBAS Augmentation Message Providing System for the the Low-cost GPS Receiver of Drone Operation (드론의 저가형 GPS 수신기용 SBAS 보강 정보 전송 시스템 제안)

  • Seok, Hyo-jeong;Yoon, Dong-hwan;Lim, Cheol-soon;Park, Byung-woon
    • Journal of Advanced Navigation Technology
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    • v.21 no.3
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    • pp.272-278
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    • 2017
  • In order to meet performance requirements specified by the ICAO in drone operation, a system that provides augmentation information such as SBAS is needed. However, the operating range of the drone is limited in situation where the drone can not received the SBAS message continuously. In this paper, we propose a system to transmit SBAS augmentation message using a separate communication channel assuming the SBAS satellite signal to the drone has been shielded. We implemented the proposed system and verified its performance in the static environment. The DGPS positioning results showed that the accuracy difference is about 10cm, which means the accuracy performance was very similar. In addition, the protection level calculated by the system also shows the difference within 2m from the value calculated by the airborne receiver.