• Bulletin of the Korean Space Science Society
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• 2004.10b
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• pp.270-273
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• 2004

The initial thermal analysis needs to be fast and efficient to reduce the feedback time for the optimal electronic equipment designing. In this study, a thermal model is developed by using power consumption measurement values of each functional breadboard, that is, semi-empirical power dissipation method. In modeling heat dissipated EEE parts, power dissipation is imposed evenly on the EEE part footprint area which is projected to the printed circuit board, and is called surface heat model. The application of these methods is performed in the development of a command and telemetry unit (CTU) for a geostationary satellite. Finally, the thermal cycling test is performed to verify the applied thermal analysis methods.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.1
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• pp.93-101
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• 2000

In this paper, propagation characteristics are analyzed under the Korean propagation condition based on the measurements for Ka-band beacon signal of COMET satellite which moves in non-geostationary orbit. Radio propagation characteristics varying as time, range, and elevation angle are presented also. As results, it is concluded that free space loss is a major parameter to the radio propagation characteristics varying as a range in clear sky. In addition, the effect of elevation angle is negligible because COMETS is observed above 40 degree.

• Journal of the Korean Solar Energy Society
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• v.22 no.3
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• pp.21-30
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• 2002

Images taken by geostationary satellite may be used to estimate solar irradiance fluxes at earth's surface. It is based on the empirical correlation between a satellite derived cloud index and the irradiance at the ground. For the validation. estimated solar radiation fluxes are compared with observed solar radiation fluxes at 16 sites over the Korean peninsular from January 1982 to December 2000. Estimated solar radiation fluxes show reliable results for estimating the global radiation with average deviation of -5.6 to +2.8% from the measured values and the yearly averaged horizontal global insolation of Korean peninsula was turned out to be $3.038kcal/m^2.day$.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.4
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• pp.403-410
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• 2005

This Paper Presents development of solar may shunt switching unit with a fully regulated Power regulation for Geostationary Earth Orbit(GEO) satellite. This shunt switching unit comprises the solar may shunt modules that regulate the solar array power. These solar array shunt modules connect/disconnect the solar array segments to/from the bus through switching actions. And that is also possible simply extension to an existing design by FPGA control logic changing. In order to verify the proposed design, the control logic and worst case analysis are analyzed and the simulation and experimental results we shown.

• Journal of Environmental Impact Assessment
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• v.22 no.4
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• pp.389-395
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• 2013

Geostationary Ocean Color Imager(GOCI), the World's first spaceborne ocean color observation satellite operated in geostationary orbit, was successfully launched on May 2010. The main missions of GOCI is the coastal environment monitoring of GOCI in order to meet the necessity of long-term climate change monitoring and research. The GOCI have higher spatial resolution than MODIS, $500m{\times}500m$, and 8 spectral ocean color channels. GOCI have a capability for observation on the coastal environment change, GOCI perform the observation with 8 times a day. In this paper, we presented the more improved results for observation on the coastal environment change than MODIS ocean color sensor and detected the spatial difference of CDOM for monitoring coastal environment change.

• Journal of Astronomy and Space Sciences
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• v.26 no.2
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• pp.267-278
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• 2009

Automation of the key flight dynamics operations for the geostationary orbit satellite mission is analyzed and designed. The automation includes satellite orbit determination, orbit prediction, event prediction, and fuel accounting. An object-oriented analysis and design methodology is used for design of the automation system. Automation scenarios are investigated first and then the scenarios are allocated to use cases. Sequences of the use cases are diagramed. Then software components and graphical user interfaces are designed for automation. The automation will be applied to the Communication, Ocean, and Meteorology Satellite (COMS) flight dynamics system for daily routine operations.

• Journal of Positioning, Navigation, and Timing
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• v.13 no.1
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• pp.25-34
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• 2024

The Satellite Based Augmentation System (SBAS) improves the accuracy and reliability of user positioning by transmitting the error correction and integrity information of the global navigation satellite system signal from geostationary satellites in real time. For this reason, SBAS was designed for aircraft operations and approach procedures and is now in operational or development stages in many countries. Time has passed since the construction of SBAS and many changes have occurred in the composition of the monitoring stations and the geostationary satellites. These changes have been investigated and the current operation and development status of SBAS globally are surveyed. The development and test schedules for the transition to dual frequency multi-constellation, an important topic in SBAS, are discussed.

• Bulletin of the Korean Space Science Society
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• 2002.05b
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• pp.40-40
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• 2002

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

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.10
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• pp.67-76
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• 2004

This paper improves existing 'fly-the-wire' based autonomous station-keeping system, suitable for geostationary satellite and introduces results of computer simulations conducted to verify the algorithm. The on-board stationkeeping system receives pseudo-range signals from two ground equipments located with long baseline, determines the orbit error in realtime and generates orbit control commands. To reduce fuel consumption, this paper proposes an on-board orbit control logic using modified fly-the-wire method. The modified fly-the-wire method de-couples error components into two dynamic modes, harmonic and linear motion. The harmonic error components are removed by applying output commands produced by feedback controller, and the linear motions are controlled by the correction ${\Delta}V\;s$ added to reference maneuvers. The reference maneuvers are generated through the ground based computer simulation and embedded or uploaded into the on-board computer with time tags. Finally, the performance of the proposed algorithm is verified through a series of computer simulations.