• 한국위성정보통신학회논문지
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• 제5권1호
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• pp.75-79
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• 2010

인공위성 구조체는 궤도상에서 열하중으로 인하여 구조적인 변형을 일으키게 된다. 이로 인하여 구조체에 장착된 관측장비들은 지상에서 조립 시에 설정된 지향방향이 변화하게 되고 원하지 않는 방향으로 관측하는 문제점이 발생한다. 위성의 관측성능이 높아질수록 성공적인 관측임무를 수행하기 위해서는 열변형에 의한 지향방향의 변화량은 줄어들어야 한다. 본 논문에서는 지구궤도 위성에 대하여 열변형 해석을 수행하여 지향오차를 예측하는 방법 및 결과에 대하여 기술한다.

• 대기
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• 제30권1호
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• pp.59-73
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• 2020

The characteristics of solar resources in South Korea were analyzed by comparing the solar irradiance derived from COMS (Communication, Ocean and Meteorological Satellite) with in-situ ground observation data (Pyranometer). Satellite-derived solar irradiance and in-situ observation showed general coincidence with correlation coefficient higher than 0.9, but the satellite observations tended to overestimate the radiation amount compared to the ground observations. Analysis of hourly and monthly irradiance showed that relatively large discrepancies between the satellite and ground observations exist after sunrise and during July~August period which were mainly attributed to uncertainties in the satellite retrieval such as large atmospheric optical thickness and cloud amount. But differences between the two observations did not show distinct diurnal or seasonal cycles. Analysis of regional characteristics of solar irradiance showed that differences between satellite and in-situ observations are relatively large in metrocity such as Seoul and coastal regions due to air pollution and sea salt aerosols which act to increase the uncertainty in the satellite retrieval. It was concluded that the satellite irradiance data can be used for assessment and prediction of solar energy resources overcoming the limitation of ground observations, although it still has various sources of uncertainty.

• 한국항공우주학회지
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• 제36권5호
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• pp.472-482
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• 2008

본 논문에서는 관측위성의 영상성능을 예측하고 해석하기 위하여 영상 성능의 주요 인자인 전체 시스템의 MTF를 산출하기 위한 시스템 MTF 구조도를 제안하였다. MTF 구조도의 각 요소에 해당하는 기본 모델은 우주 환경에서 광-구조, 열 변형, 자세 및 동역학 특성과 MTF간의 수학적인 관계식으로 표현된다. MTF 기본 모델은 중앙차폐가 있는 광학계의 회절한계, 수차, 비촛점, LOS 지터, 선형운동, 검출기 Integration MTF 등으로 구성된다. 가상의 지구관측위성모델에 대해 영상성능 예측모델링 기법을 적용하여 적절한 결과를 얻을 수 있음을 보였다. 각 기본 모델을 바탕으로 관측위성의 전체 영상성능을 해석하고 개념설계 단계에서 영상성능에 영향을 주는 주요한 설계 매개변수를 도출할 수 있다.

• 대한임베디드공학회논문지
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• 제13권5호
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• pp.253-259
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• 2018

Recently, small satellite industries are rapidly changing. Demand for high performance small satellites is increasing with the expansion of Earth Observation Satellite market. A next-generation small satellites require a higher resolution image storage capacity than before. However, there is a problem that the HW configuration of the existing small satellite image storage device could not meet these requirements. The conventional data storing system uses SDRAM to store image data taken from satellites. When SDRAM is used in small satellite platform of a next generation, there is a problem that the cost of physical space is eight times higher and satellite price is two times higher than NAND Flash. Using the same satellite hardware configuration for next-generation satellites will increase the satellite volume to meet hardware requirements. Additional cost is required for structural design, environmental testing, and satellite launch due to increasing volume. Therefore, in order to construct a low-cost, high-efficiency system. This paper shows a next-generation solid state recorder unit (SSRU) using MRAM and NAND Flash instead of SDRAM. As a result of this research, next generation small satellite retain a storage size and weight and improves the data storage space by 15 times and the storage speed by 4.5 times compare to conventional design. Also reduced energy consumption by 96% compared to SDRAM based storage devices.

• 항공우주기술
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• 제12권2호
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• pp.163-172
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• 2013

통신, 해양, 기상의 세 분야 복합 임무를 수행하는 천리안위성(Communication Ocean Meteorological Satellite: COMS)은 정지궤도 동경 $128.2^{\circ}$에서 2011년 4월부터 현재 정규 운영 임무를 수행하고 있다. 기상 및 해양 임무 운영과 위성 제어 및 관리를 위해 위성 임무 계획이 매일 수행되고 있다. 위성 임무 계획은 위성 실시간 운영을 통해 위성에 전송되고, 전송된 임무 계획에 따라 위성은 임무를 수행한다. 본 논문에서는 천리안위성의 임무 계획 특성으로 지상국 장비 구성과 일일, 주간, 월간, 계절별 운영 업무 특성을 논하였다. 천리안위성의 정규 운영 첫 1년간 운영 결과에 대한 토의를 통해 성공적인 임무계획 결과 확인도 제시하였다.

• 대한원격탐사학회지
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• 제27권6호
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• pp.743-752
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• 2011

One of main concerns of operators of the Earth observation satellite is taking images as many as possible under the constraints of satellite resources during fixed period. In order to achieve this goal, satellite operators are strongly required to generate the optimized image collection plans, and it is a very time consuming process to achieve an optimized image collection plan when it is done by manual. This paper suggests automation of image collection planning based on the dynamic programming algorithm to reduce the time required for image collection planning. The validity of the proposed method is tested using operating satellite system and the result is given in this paper.

• 천문학회보
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• 제37권2호
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• pp.195.1-195.1
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• 2012

Korea Aerospace Research Institute has developed an earth observation satellite whose primary mission objective is to provide high resolution electro optical earth images for Geographical Information Systems (GIS) establishment and the applications for environmental, agriculture and ocean monitoring. It was successfully launched into its mission orbit by using a commercial launch vehicle on 18th of May, 2012. This paper describes a series of launch activity at the launch site including its transportation to the launch site. Before conducting the launch site operation, satellite operation plane was prepared. Combining the satellite operation plan and launch vehicle activities, an integrated launch site operation plan and schedule have been drawn up. After arrival of the spacecraft at the launch site, post-ship check out has been conducted. And then it was fuel loaded and integrated with launch vehicle hardware. After completion of final electrical check out, count down procedure was executed. on 18th of May, it was launched into the space and was separated from the launch vehicle as planned. About 3 months of early operation and calibration/validation, now the satellite is conducting its normal mission.

• 대기
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• 제16권4호
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• pp.371-378
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• 2006

The surface observation probability system (SOPS) of the Korea Multi-Purpose Satellite (KOMPSAT) has been developed based on the climatological distribution of cloud coverage and the expected passage of satellite orbit. While the optical camera loaded on KOMPSAT series has been operated with the purpose of observing earth's surface, it cannot see the surface when an obstacle (i.e., cloud) exists between them. In the present study, cloud information of International Satellite Cloud Climatology Project incorporates into high resolution grid of the KOMPSAT-3 orbit. The characteristics of the KOMPSAT SOPS are discussed.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1224-1226
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• 2003

Dust-storm is one of the heaviest hazardous weather which frequently affects most part of northern China in spring. Satellite multi-spectral observations can provide significant information for detecting and quantitative determining the property of dust-storm . An algorithm to monitor dust-storm automatically was developed based on satellite observation. The algorithm utilizes split widows technique and spectral classification technique and also developed a new dust remote sensing product Infra -red Difference Dust Index (IDDI) proxy dust-loading dataset using GMS-5.

• 한국통신학회논문지
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• 제24권8A호
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• pp.1149-1155
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• 1999

저궤도위성 시스템은 지구 및 과학 관측분야(지도제작, 해양생태감시, 우주환경 관측, 기상관측, 대기관측 등)와 군사분야(군사통신, 첩보, 적군정찰 등)에서 사용되었으며, 최근에는 상업적 이용을 위해 GMPCS를 위한 이동위성통신 분야에서 개발이 진행되고 있다. 우리나라에서는 1999년 10월 발사를 목표로 다목적 실용위성 1호가 개발되고 있다. 본 논문에서는 저궤도위성 관제시스템을 위한 위성링크를 설계하고 위성의 움직임에 따른 위성의 통과시간과 지구국의 양각 관계를 계산한다. 그리고 수신데이터의 패킷오율을 확률이론에 의해 유도하고, RT모드와 PB모드 그리고 RT+RNG모드에 대한 패킷오율을 위성과 통과시간에 따라 예측한다. 패킷오율 계산결과는 RT모드, PB모드, RT+RNG모드의 순으로 좋으며 EFP의 평균도 각각 99.999999%, 99.995945%로 계산되었다. 따라서 원격측정 데이터의 전송순서는 위성의 통과시간에 따른 PER 순서로 즉, RT, PB, RT+RNG순으로 결정한다.