• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.179-182
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• 2007

COMS (Communication, Ocean and Meteorological Satellite) is a geosynchronous satellite and has been developing by KARI and Astrium for Ka-band communication, ocean observation and meteorological observation. COMS Chemical Propulsion System (CPS) uses a bipropellant propulsion subsystem, which is applied for transferring COMS from GTO to GEO (mission orbit) and implementing station-keeping manoeuvres. In this paper COMS CPS is briefly introduced for understanding. A few of mathematical thermodynamic modelings of bipropellant propulsion system in literatures are reviewed and authors has studied those models for developing a computer program, which predicts variations of thermodynamic properties such as temperature and pressure histories in the helium pressurant tank, MMH propellant tank and NTO propellant tank during LAE firing and on-orbit manoeuvrings. The CPS thermodynamic model may be used to compute pressurant and propellant masses and to size tank volumes.

• 시스템엔지니어링학술지
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• 제1권1호
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• pp.32-38
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• 2005

This paper presents the brief generation process of system requirements for Smart UAV from a development objective. The current Smat UAV requirements deal with the restricted life cycle from development to test and verification exclusive of full life cycle because of the new technology demonstration research program funded by governments. The Smart UAV system consists of flight vehicle, avionics, communication link, payload, ground control station and ground supporting system. In this paper, top-down flown requirements are introduced how to allocate to each sub-system.

• International Journal of Internet, Broadcasting and Communication
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• 제10권2호
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• pp.13-18
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• 2018

Drones are controlled by the remote pilot from the ground stations using the radio control or autonomously following the pre-programmed flight plans. In this paper, we develop a method and an optimal path search system for providing 3D augmented reality flight (ARF) images for safe and efficient flight control of drones. The developed system consisted of the drone, the ground station and user terminals, and the optimal path search server. We use the Dijkstra algorithm to find the optimal path considering the drone information, flight information, environmental information, and flight mission. We generate a 3D augmented reality flight (ARF) image overlaid with the path information as well as the drone information and the flight information on the flight image received from the drone. The ARF image for adjusting the drone is generated by overlaying route information, drone information, flight information, and the like on the image captured by the drone.

• 한국광학회지
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• 제11권1호
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• pp.6-12
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• 2000

위성에 탑재된 지구관측용 카메라는, 지상의 망원경과 같은 원리로, 우주상공에서 지표면 관측을 자동적으로 수행하고 관측정보를 지상으로 전달해 주는 장치다. 이용 목적에 따라 카메라의 해상도 또는 분해능, 관측대역, 관측폭, 위성의 궤도 등의 규격이 결정된다. 고해상도는 카메라 관련 제반 기술 및 경험이 부족한 국내의 여건에 적합한 소형 위성용 고해상도 카메라의 규격을 제시하며 이에 따른 광학 설계와 제작, 조립 및 측정오차를 제시한다.

• Journal of Positioning, Navigation, and Timing
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• 제10권2호
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• pp.145-151
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• 2021

According to the Korea Augmentation Satellite System (KASS) system milestone, Site Acceptance Test (SAT) has three steps test until the end of the project. SAT#1 is the first time of SAT steps and verify the KASS Reference Station (KRS) and Sub System (S/S) for the monitoring and controllable. After the equipment and software were installed at the Mission Control Center (MCC) with Central Monitoring and Control Simulator (CMS) for the SAT#1, the 1:1 test was progressed when the KRS and S/S are ready to test. SAT#1 has a 10 steps test case and it was progressed each KRS sites. The test was finished throughout the real-time monitoring and the data collection including the data analysis all of the 7 KRS sites. Finally SAT#1 was completed on December 2020 with successfully.

• 천문학회보
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• 제44권2호
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• pp.56.4-56.4
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• 2019

The Korea Astronomy and Space Science Institute (KASI) has been collaborating with the NASA's Goddard Space Flight Center, to install a coronagraph on the International Space Station (ISS). The coronagraph will utilize spectral information to simultaneously measure electron density, temperature, and velocity. As a first step, we developed a new coronagraph and launched it on a stratospheric balloon in 2019 (BITSE) from Fort Sumner, New Mexico in USA. As the next step, the coronagraph will be be further developed, installed and operate on the ISS (CODEX) in 2022 to address a number of important questions (e.g., source and acceleration of solar wind, and coronal heating) in the physics of the solar corona and the heliosphere. Recently, BITSE has been launched at Fort Sumner, New Mexico. In this presentation, we will introduce the BITSE mission and discuss recent progress.

• 천문학회보
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• 제46권2호
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• pp.79.3-79.3
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• 2021

The Korea Astronomy and Space Science Institute (KASI) has been developing a diagnostic coronagraph to be deployed in 2023 on the International Space Station (ISS) in collaboration with the NASA Goddard Space Flight Center (GSFC). The mission is known as "Coronal Diagnostic Experiment (CODEX)", which is designed to obtain simultaneous measurements of the electron density, temperature, and velocity using multiple filters in the 2.5-10 Rs range. The coronagraph will be installed and operated on the ISS to understand the physical conditions in the solar wind acceleration region, and to enable and validate the next generation space weather models. In this presentation, we will introduce recent progress and future plan.

• 항공우주기술
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• 제13권1호
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• pp.37-43
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• 2014

저궤도 위성을 운영하는 지상국에서는 10분 내외의 교신 시간 동안 위성의 건강 상태를 확인한 후 영상 촬영을 위한 임무 명령을 전송하거나 촬영한 영상을 수신한다. 제한된 교신 시간동안 매일의 임무를 위한 일련의 절차를 완료하기 위해 위성 및 지상국 시스템에서는 적절한 수준의 자율성이 적용되어 있다. 예를 들어 위성의 자세 및 궤도를 유지하기 위한 제어 로직은 운영자의 개입 없이도 오랜 시간동안 자동으로 수행되어야 하므로 높은 자율성을 갖는 부분이다. 이와는 대조적으로 위성의 고장 관리 로직의 경우 고장 상황 인지 및 안전 조치는 위성에서 자동으로 수행되지만 대체적으로 고장의 원인 판단 및 복구 절차는 지상에서 수행하도록 설계하므로 상대적으로 낮은 자율성을 갖는 부분이라 할 수 있다. 위성의 자율성 수준은 지상국 운영에도 영향을 준다. 지상국에서는 촬영 임무를 위한 일련의 명령 세트 등을 생성한다. 위성이 좀 더 높은 수준의 자율성을 갖는다면, 지상국에서 수행하는 동작의 일부를 위성에서 수행할 수 있을 것이며 지상국의 절차를 간소화할 수 있을 것이다. 이 논문에서는 위성의 자율성 수준에 대해 논의하고 적절한 자율성 수준을 위한 설계 개념을 제안한다.

• 한국산학기술학회논문지
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• 제2권2호
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• pp.81-89
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• 2001

우주 항공위성 시스템은 변하는 불확실한 우주항공 환경에(서) 운행되고 지상기지국으로부터의 원격통신 없이 장시간 동안 동작해야 할 자율적인 능력이 요구되고, 결함 없이 임무를 수행하여야 하며, 시스템에서 계측된 데이터의 신뢰성을 유지하기 위한 고장 상태 검출과 오류 수정 시스템을 차보하는 것이 중요하다. 본 논문에서는 확장 칼만 필터 기법을 적용한 동적모델 시뮬레이션 기법(High Fidelity, Dynamic Model-based Simulation)을 제안하였으며, 제안된 시스템은 비정상적인 데이터의 효과적인 검출과 대응이 가능해짐으로써 신뢰성 있는 우주항공위성시스템을 구축하도록 자동 상태 진단/데이터 시스템에 고장검출/오류수정 시스템을 적용하는 것이다. (Autonomous Spacecraft Health Monitoring/Data Validation Control System : ASHMDVCS).

• Journal of Astronomy and Space Sciences
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• 제27권3호
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• pp.253-262
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• 2010

The electrical power system (EPS) of Korean satellites in low-earth-orbit is designed to achieve energy balance based on a one-orbit mission scenario. This means that the battery has to be fully charged at the end of a one-orbit mission. To provide the maximum solar array (SA) power generation, the peak power tracking (PPT) method has been developed for a spacecraft power system. The PPT is operated by a software algorithm, which tracks the peak power of the SA and ensures the battery is fully charged in one orbit. The EPS should be designed to avoid the stress of electronics in order to handle the main bus power from the SA power. This paper summarizes the results of energy balance to achieve optimal power sizing and the actual trend analysis of EPS performance in orbit. It describes the results of required power for the satellite operation in the worst power conditions at the end-of-life, the methods and input data used in the energy balance, and the case study of energy balance analyses for the normal operation in orbit. Both 10:35 AM and 10:50 AM crossing times are considered, so the power performance in each case is analyzed with the satellite roll maneuver according to the payload operation concept. In addition, the data transmission to the Korea Ground Station during eclipse is investigated at the local-time-ascending-node of 11:00 AM to assess the greatest battery depth-of-discharge in normal operation.