• Aerospace Engineering and Technology
• /
• v.10 no.1
• /
• pp.156-166
• /
• 2011

COMS (Communication Ocean and Meteorological Satellite), the Korea's first geostationary Earth observation satellite, started to operate 24 hours to observe Land/Ocean/Atmosphere with the MI (Meteorological Imager) and GOCI (Geostationary Ocean Color Imager). After the successful completion of the IOT (In-Orbit Test), the satellite is in normal operation from April of 2011. This paper describes an algorithm for scan mirror emissivity compensation of the COMS MI and its software implementation.

• Journal of Satellite, Information and Communications
• /
• v.8 no.1
• /
• pp.89-100
• /
• 2013

Communication Ocean Meteorological Satellite (COMS) for the hybrid mission of meteorological observation, ocean monitoring, and telecommunication service was launched onto Geostationary Earth Orbit on June 27, 2010 and it is currently under normal operation service after the In-Orbit Test (IOT) phase. The COMS is located on $128.2^{\circ}$ East of the geostationary orbit. In order to perform the three missions, the COMS has 3 separate payloads, the meteorological imager (MI), the Geostationary Ocean Color Imager (GOCI), and the Ka-band antenna. Each payload is dedicated to one of the three missions, respectively. The MI and GOCI perform the Earth observation mission of meteorological observation and ocean monitoring, respectively. During the IOT phase the functionalities and the performances of the COMS satellite and ground station have been checked through the Earth observation mission operation for the observation of the meteorological phenomenon over several areas of the Earth and the monitoring of marine environments around the Korean peninsula. The operation characteristics of meteorological mission and ocean mission are described and the mission planning for the COMS is discussed. The mission operation results during the COMS IOT are analyzed through statistical approach for the study of both the mission operation capability of COMS verified during the IOT and the satellite image reception capacity achieved during the IOT.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
• /
• v.22 no.3
• /
• pp.3-16
• /
• 2011

천리안 위성은 4개 정부 부처 공동 사업으로, 통신 서비스, 해양 기상 관측 서비스 제공을 목적으로 개발된 복합 위성으로, 그중 통신 서비스를 담당하는 통신 탑재체는 방송통신위원회 출연으로 한국전자통신연구원(ETRI)가 주관, 개발하여 성공한 순수 국산 개발품으로, 위성 발사 성공 후 시험 검증을 거쳐 현재 정상 운용 중에 있다. 우주 인증 획득을 목적으로 개발한 통신 탑재체는 위성 스위칭 중계기와 다중 빔 안테나로 구성되었으며, 구성 부품들인 능동 부품과 수동 부품들은 대부분 국내 연구진에 의해 설계, 제작 시험 검증되어 중계기 및 안테나 시스템 종합화, 통신 탑재체 및 위성체 우주 환경 시험을 성공적으로 수행되었다. 위성 발사 성공 후에, 정지 궤도상에서의 통신 탑재체 궤도내 시험을 완료를 통해 순수국산 개발된 통신 탑재체의 설계 제작 기술에 대한 정지 궤도 우주환경에서도 정상 동작됨을 입증하였다. 통신 탑재체는 다양한 우주 조건에서의 다양한 기술 확보와 차세대 멀티미디어 위성 서비스 개발에 활용하고자 한다. 본 논문은 통해기 통신 탑재체 설계 제작 시험 기술을 소개하고, 활용 계획에 대해 언급하고자 한다.

• Korean Journal of Remote Sensing
• /
• v.37 no.2
• /
• pp.359-365
• /
• 2021

GEO-KOMPSAT-2A (GK2A) AMI (Advanced Meteorological Imager) Best Detector Select (BDS) map is pre-determined and uploaded before the satellite launch. After the launch, there is some possibility of a detector performance change driven by an abrupt temperature variation and thus the status of BDS map needs to be evaluated and updated if necessary. To investigate performance of entire elements of the detectors, AMI BDS analyses were conducted based on a technical note provided from the AMI vendor (L3HARRIS). The concept of the BDS analysis is to investigate the stability of signals from detectors while they are staring at targets (deep space and internal calibration target). For this purpose, Long Time Series (LTS) and Output Voltage vs. Bias Voltage (V-V) methods are used. The LTS for 30 secs and the V-V for two secs are spanned respectively for looking at the targets to compute noise components of detectors. To get the necessary data sets, these activities were conducted during the In-Orbit Test (IOT) period since a normal operation of AMI is stopped and special mission plans are commanded. With collected data sets during the GK2A IOT, AMI BDS map was intensively examined. It was found that about 1% of entire detector elements, which were evaluated at the ground test, showed characteristic changes and those degraded elements are replaced by alternative best ones. The stripping effects on AMI raw images due to the BDS problem were clearly removed when the new BDS map was applied.

• Aerospace Engineering and Technology
• /
• v.13 no.2
• /
• pp.115-121
• /
• 2014

GEO-KOMPSAT-2 (GK2) program, which develops two advanced geostationary satellites simultaneously after the successful COMS mission (2010~present), is on going. An improved next generation meteorological payload and space weather sensors will be equipped on the GK2A. The space weather sensor will be the Korea's first geostationary space environment monitoring payload. Main objectives of the project are its applications into space weather forecasting and pre-warning of hazardous space weather by monitoring physical phenomena such as distribution of high energetic particles, Earth's magnetic fields and charging currents on the spacecraft at a geostationary orbit using the three space weather sensors(energetic particle detector, magnetometer and charging monitor). The summary of the GK2A space weather sensor development and its system and interface designs were described in the paper.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
• /
• v.22 no.3
• /
• pp.42-49
• /
• 2011

• Aerospace Engineering and Technology
• /
• v.11 no.2
• /
• pp.12-18
• /
• 2012

In this paper, impacts on the COMS MI images during the COMS eclipse period were analyzed and the method to eliminate the contaminated area was investigated. Main effect on the meteorological images during the eclipse is a stripping effect due to a strong stray light. The quantitative analyses were conducted during the COMS In-Orbit-Test period and the impacts of the stray light on the four infrared channels of the COMS MI according to the distance with respect to the Sun were examined. Based on the typical case of the stray light influence on the infrared channel of the MI, the intensity of contamination due to the stray light was investigated for each channel using the computed COMS eclipse information. The effectiveness of removal of a contaminated area by replacing the SWIR with the combined WINDOW channels was promising.

• Journal of Satellite, Information and Communications
• /
• v.8 no.2
• /
• pp.80-87
• /
• 2013

Communication Ocean Meteorological Satellite (COMS) has the hybrid mission of meteorological observation, ocean monitoring, and telecommunication service. The COMS is located at $128.2{\circ}$ east longitude on the geostationary orbit and currently under normal operation service since April 2011. In order to perform the three missions, the COMS has 3 separate payloads, the meteorological imager (MI), the Geostationary Ocean Color Imager (GOCI), and the Ka-band communication payload. The satellite controls for the three mission operations and the satellite maintenance are done by the real-time operation which is the activity to communicate directly with the satellite through command and telemetry. In this paper the real-time operation for COMS is discussed in terms of the ground station configuration and the characteristics of daily, weekly, monthly, seasonal, and yearly operation activities. The successful real-time operation is also confirmed with the one year operation results for 2011 which includes both the latter part of the In-Orbit-Test (IOT) and the first year normal operation of the COMS.

• The Bulletin of The Korean Astronomical Society
• /
• v.37 no.2
• /
• pp.211.2-211.2
• /
• 2012

천리안위성은 통신, 해양, 기상 임무를 띤 우리나라 최초의 정지궤도복합위성으로 지난 2010년 6월 27일 성공적으로 발사된 후 동경 128.2도, 적도 상공 약 35,800 km 고도의 정지궤도에 안착되었다. 이 후 약 6개월 여의 궤도상시험 기간과 2개월의 안정화 기간을 거쳐 2011년 4월 1일, 기상청은 위성자료 서비스를 위한 정규운영을 시작하였다. 천리안위성의 기상탑재체인 기상영상기는 다중채널 복사계로 한반도 주변뿐만 아니라 전 지구적 기후 변화 및 대기 운동 그리고 급변하는 기상상황을 감시하기 위해 실시간 관측과 전송 시스템을 갖추고 있다. 이 기상영상기를 운용하는 기상청 국가기상위성센터 지상국에서는 자료수신 및 영상전처리시스템을 갖추고 수신된 위성신호로부터 영상 분리 후 복사보정 및 기하보정을 수행하며, 위성자료배포시스템을 통해 일정 시간 간격 내에 사용자들에게 처리 자료를 배포하고 있다. 영상 복사보정은 기상영상기 내의 각 채널별 디텍터가 감지한 지구복사휘도의 전기적 신호를 지상에서 복사휘도와 휘도온도 값으로 변환하는 작업이다. 절대검정체로서 흑체와 우주보기 값을 이용하는 적외채널과 달리, 가시채널 디텍터는 절대검정체가 탑재되어있지 않기 때문에 우주보기 값 외에 대리검정 방법을 이용한다. 이러한 가시채널 노화도 분석에 달 관측을 통한 비교 분석이 한 방법으로 제시되고 있다. 천리안위성 기상영상기의 정규운영 1년간의 가시채널 디텍터의 노화도는 6 % 이내로 측정되었고, 이는 일반적인 정지궤도위성 센서의 노화도인 6 % 내외 값 변화량에 견주어 잘 운용되고 있음을 시사한다. 본 논문에는 천리안위성 기상영상자료의 품질 및 매개변수의 변화 경향도 함께 제시하였으며, 달을 이용한 기상영상기 노화 분석과 보정에 관한 내용을 싣고 있다.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.40 no.5
• /
• pp.439-445
• /
• 2012

The COMS(Communication, Ocean, and Meteorological Satellite) is subjected to shock loads when the stage or fairing of a launch vehicle is separated and the satellite is separated from the launch vehicle during the launch vehicle flight. And, after the satellite is separated from the launcher, the COMS is subjected to shock loads when the solar array is deployed, Ka-Band communication antenna is deployed, and meteorological imager radiator cover is released. In order to validate the satellite safety against these shock loads on ground, shock tests were performed. In this paper, the shock tests performed in the course of the COMS development are described, and the method to assess the test result is presented with an example of Geostationary Ocean Color Imager(GOCI). In Ariane-5 launch vehicle, the clampband release shock for satellite separation is lower than the fairing or stage separation. In this paper, the extrapolation method to take into account the maximum shock load from the launch vehicle by using the satellite separation shock test result is also introduced.