• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.8
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• pp.834-841
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• 2010

The STSAT-3 (science and technology satellite) is the first satellite whose entire structure was made of composite materials in Korea and it will be launched later in 2011. As like other small satellites, it is also equipped with several advanced instruments whose major objectives focused on the scientific tests in space. The HPS (hall thruster propulsion system) using xenon gas as a propellant has been developed and its overall ground tests were conducted. This research emphasizes on the technologies and procedure applied to the development of the entire HPS and its function and environment tests.

• Journal of Aerospace System Engineering
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• v.18 no.2
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• pp.104-116
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• 2024

A satellite is ultimately verified by performing a coupled load analysis with the launch vehicle. To increase the accuracy of the coupled load analysis results, it is important to have good accuracy of the finite element model. Therefore, finite element model correlation is essential. In general, model correlation is performed by changing the material properties and thickness one by one, but this process takes a lot of time and cost. The current paper proposes an efficient model correlation method using optimization. Significant variables were selected through analysis of variance, and the time and cost required for analysis and optimization were reduced by using the Kriging surrogate model. The method proposed in this paper can be applied only with the vibration test results, and it has a great advantage in terms of efficiency in that it can significantly reduce the numerical calculation cost and time required.

• Electronics and Telecommunications Trends
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• v.19 no.1 s.85
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• pp.88-93
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• 2004

본 논문은 미국, 유럽, 일본 등이 통신방송위성 개발능력 확보 및 위성을 통한 새로운 통신서비스 실험을 위하여 통신시험위성을 개발하여 왔는데, 어떤 시험위성들이 있는지, 목적은 무엇인지, 어떤 기관들이 주관이 되었는지, 시험위성의 수명, 무게, 전력은 어느 정도 되는지, 비용은 얼마나 되는지를 살펴본다. 이는 국내 최초의 통신시험위성이 될 통신해양기상위성의 통신탑재체의 개발방향을 설정하고, 향후 국내개발 통신위성의 방향을 제시해주리라 생각된다.

• Aerospace Engineering and Technology
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• v.2 no.1
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• pp.133-139
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• 2003

Position and trajectory data in-flight rocket are important informations to determine flight safety of rocket. In general tracking system, radar and transponder are used to acquire position information. Rocket position and trajectory can be determined by RF communication between ground station and in-flight rocket, and antenna position date. In this paper, it explains the ranging system which is low resolution rather than radar system but system configuration is simple. Therefore this system is useful for experimental flight vehicle.

• Korean Journal of Remote Sensing
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• v.37 no.5_2
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• pp.1235-1243
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• 2021

Geostationary Ocean Color Imager 2 (GOCI-II) on Geo-KOMPSAT-2 (GK2B)satellite was developed as a mission successor of GOCI on COMS which had been operated for around 10 years since launch in 2010 to observe and monitor ocean color around Korean peninsula. GOCI-II on GK2B was successfully launched in February of 2020 to continue for detection, monitoring, quantification, and prediction of short/long term changes of coastal ocean environment for marine science research and application purpose. GOCI-II had already finished IAC and IOT including early in-orbit calibration and had been handed over to NOSC (National Ocean Satellite Center) in KHOA (Korea Hydrographic and Oceanographic Agency). Radiometric calibration was periodically conducted using on-board solar calibration system in GOCI-II. The final calibrated gain and offset were applied and validated during IOT. And three video parameter sets for one day and 12 video parameter sets for a year was selected and transferred to NOSC for normal operation. Star measurement-based INR (Image Navigation and Registration) navigation filtering and landmark measurement-based image geometric correction were applied to meet the all INR requirements. The GOCI2 INR software was validated through INR IOT. In this paper, status and results of IOT, radiometric calibration and INR of GOCI-II are analysed and described.

• Korean Journal of Remote Sensing
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• v.36 no.6_1
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• pp.1323-1337
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• 2020

GEO-KOMPSAT-2A AMI (Advanced Meteorological Imager) radiometric calibration evaluation is an essential element not only for functional and performance verification of the payload but for the quality of the sensor data. AMI instrument consists of six reflective channels and ten thermal infrared ones. One of the key parameters representing radiometric properties of the sensor is a SNR (Signal-to-Noise Ratio) for the reflective channels and a NEdT (Noise Equivalent delta Temperature) for the IR ones respectively. Other important radiometric calibration parameters are a dynamic range and a gain value related with the responsivity of detectors. To verify major radiometric calibration performance of AMI, an offline radiometric evaluation tool was developed separately with a real-time AMI data processing system. Using the evaluation tool, validation activities were carried out during the GEO-KOMPSAT-2A In-Orbit Test period. The results from the evaluation tool were cross checked with those of the HARRIS, which is the AMI payload vendor. AMI radiometric evaluation activities were conducted through three phases for both sides (Side 1 and Side 2) of AMI payload. Results showed that performances of the key radiometric properties were outstanding with respect to the radiometric requirements of the payload. The effectiveness of the evaluation tool was verified as well.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.8 s.111
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• pp.773-787
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• 2006

An airborne radar is an essential aviation electronic system for the aircraft to perform various civil and/or military missions in all weather environments. This paper presents the design, development, and test results of the multi-mode X-band pulsed Doppler radar system test model for helicopter-borne flight test. This radar system consists of 4 LRUs(Line-Replacement Unit), which include antenna unit, transmitter and receiver unit, radar signal & data processing unit and display Unit. The developed core technologies include the planar array antenna, TWTA transmitter, coherent I/Q detector, digital pulse compression, MTI, DSP based Doppler FFT filter, adaptive CFAR, moving clutter compensation, platform motion stabilizer, and tracking capability. The design performance of the developed radar system is verified through various ground fixed and moving vehicle test as well as helicopter-borne field tests including MTD(Moving Target Detector) capability for the Doppler compensation due to the moving platform motion.

• Aerospace Engineering and Technology
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• v.5 no.2
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• pp.108-113
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• 2006

This paper includes the test results of KOMPSAT-2 payload downlink system which were measured for the purpose of performance verification. The antenna beam patterns which indicates the status of the interface & antenna itself, were measured as well as the antenna VSWR. The checkout of the transponder & its spectrum was followed and this made sure that there was no spurious output distinguished. Finally a test for BER verification was conducted between satellite and receiving system for their compatibility through the antenna-to-antenna connection using an antenna hat. Verification tests for an RF system should be performed after relocation, integration and test for environments in order to make sure that no degradation happens.

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.363-364
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• 2009

초소형 영상 분광기 COMIS는 과학기술위성3호에 탑재되어 지표면 및 대기의 분광 촬영을 할 예정으로 개발되고 있다. COMIS는 궤도 700km 상공에서 약 30m의 해상도 및 30km의 관측 폭을 갖고 있으며, 가시광 및 근적외선 영역에서 $16{\sim}62$대역($2{\sim}15nm$ 파장 분해능)의 초분광 관측을 수행할 수 있다. COMIS는 CCD 등의 일부 전자 부품 단위에서의 수입을 제외하곤 설계, 제작 및 평가를 포함한 모든 개발이 국내의 연구진 및 업체에 의하여 진행되고 있다. COMIS는 2010년 말 발사를 목표를 개발되고 있으며, 현재 시험 모델 개발이 진행 중에 있다. 본 논문에서는 현재 진행 중인 시험 모델의 개발 현황을 보고한다.

• Journal of Satellite, Information and Communications
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• v.2 no.2
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• pp.29-35
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• 2007

COMS satellite is a multipurpose satellite in the geostationary orbit, which accommodates multiple payloads of the Ka band Satellite Communication Payload, Meteorological Imager, and Geostationary Ocean Color Imager into a single spacecraft platform. In this paper, Korea's first innovative geostationary Communication, Ocean and Meteorological Satellite (COMS) program is introduced which is fully funded by Korean Government. The satellite platform is based on the Astrium EUROSTAR 3000 communication satellite, but creatively combined with MARS Express satellite platform to accommodate three different payloads efficiently for COMS. The goals of the Ka band satellite communication mission are to in-orbit verify the performances of advanced communication technologies and to experiment wide-band multi-media communication service. The Meteorological Imager mission is to continuously extract meteorological products with high resolution and multi-spectral imager, to detect special weather such as storm, flood, yellow sand, and to extract data on long-term change of sea surface temperature and cloud. The Geostationary Ocean Color Imager mission aims at monitoring of marine environments around Korean peninsula, production of fishery information (Chlorophyll, etc.), and monitoring of long-term/short-term change of marine ecosystem. The system design difficulties are in the different kinds of payload mission requirements of communication and remote sensing purposes and how to combine them into one to meet the overall satellite requirements. In this paper, Ka band communication payload system is more highlighted.