• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.134-142
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• 2004

This is a survey report of Japan's geo-stationary satellite development. Owing to Japanese government's ambitious space development efforts since 1950's, Japan became the fourth country that launched successfully its own satellite by using its own launch vehicle with the launch of Japan's first satellite, Ohsumi, in 1970. Since then Japan is maintaining a world leader's position in space development with continuous technology accumulation. Japan is injected 97 satellites into orbit(third in the world) by the end of 2003 including 18 science satellite series, 7 technology experiment satellite series, 5 meteorological satellites, and numerous telecommunication and broadcasting satellites, etc. With successful delivery of Optus C1 satellite to Sing Tel Optus Pty., Ltd. in Australia in June 2003 by MELCO, Japan is capable of competing in the international geo-stationary satellite market.

• Journal of Satellite, Information and Communications
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• v.11 no.4
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• pp.74-80
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• 2016

In this paper, the modeling and implementation results of the operational test and evaluation tool of the KASS up-link station composed of the GEO(Geostationary Earth Orbit) satellite signal analysis tool model that analyzes the GEO satellite signal and the GEO message analysis tool model that analyzes the GEO satellite navigation message. In addition, we describe the results of software modeling and implementation of some software models of GEO satellite and KASS up-link stations that can generate and provide simulated signals to operational test and evaluation tools of these KASS up-link stations.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.8
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• pp.747-752
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• 2007

Domestic satellite development programme is generally classified into two categories: COMS as GEO satellite and KOMPSAT as LEO one. Each satellite has the on-board propulsion system fulfilling its own mission requirements. The COMS propulsion system provides the thrust and torque required for the insertion into GEO, attitude and orbit control/adjustment of spacecraft. It is the well-known Chemical Propulsion System(CPS) using bipropellants. On the other hand, the monopropellant propulsion system is employed in KOMPSAT, and its main role is on-station attitude control excluding the orbit transfer function. In this study, these two representative propulsion systems are compared and analysed as well, in terms of essential differences and important characteristics.

• Journal of Aerospace System Engineering
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• v.10 no.4
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• pp.90-97
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• 2016

GEO-KOMPSAT-2A and GEO-KOMPSAT-2B are under development by KARI to replace the COMS mission, and will be launched in 2018 and 2019, respectively. GEO-KOMPSAT-2 will be launched and injected into the GTO (Geostationary Transfer Orbit) by the Ariane V launcher. Once injected into the GTO, the satellites are transferred to the drift orbit by applying a series of apogee engine burns. The burn epoch time, duration, and intervals are selected such that the satellite is placed closest to the target drift longitude, or at the drift start longitude. For GEO-KOMPSAT-2, four or five LAE (Liquid Apogee Engine) burns will be applied for drift orbit injection. This paper establishes the GEO-KOMPSAT-2 LAE burn plan, considering predefined constraints and adjustments, taking into account the perturbing forces. Two approaches have been analyzed: the first is a single shot approach, whereas the other is an iteration based optimal solution. Optimal solution has been obtained using the Focusleop, a geostationary satellite LEOP tool.

• Aerospace Engineering and Technology
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• v.13 no.2
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• pp.7-17
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• 2014

This technical paper deals with development of on-board orbit generation algorithm for GEO Satellite. This paper presents the research analysis results performed in order to improve the accuracy of the existing algorithm used for generating real-time orbit information for GEO satellite. The error impact on orbit accuracy due to the orbit error sources were analyzed with the algorithm suggested by this research. As a result of the analyses, it is found that the initial orbit should be determined with an accuracy of less than 50 m and the reference position angle error for the ground station and the satellite should be maintained within ${\pm}0.0025deg$ in order to meet the orbit accuracy specification. The development of on-board flight software based on the new algorithm was accomplished and the performance verification is ongoing by using a software based performance verification tool.

• Journal of Aerospace System Engineering
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• v.12 no.1
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• pp.10-16
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• 2018

In 2018 and 2019, GEO-KOMPSAT-2A and GEO-KOMPSAT-2B will be launched in order to succeed the COMS mission. The two satellites will be collocated in $128.25{\pm}0.05$ degrees East. For precise ranging and orbit determination, the GEO-KOMPSAT-2B will be equipped with LRA (Laser Retroreflector Assembly) and SLR (Satellite Laser Ranging) systems will be utilized. This systems are located in Geochang. In this case, the laser beam emitted from the SLR station can cause problems in terms of safety of optical payloads and image quality. As a solution of this possibility, the laser ranging will be done during the night time when the shutters of the optical payloads remain closed. Still, the optical payload of the GEO-KOMPSAT-2A is not safe from the laser beam because its optical payload shall continue its mission for 24 hours a day. In order to handle this problem, the laser ranging shall be limited to time slots when the angular distance between two satellites observed from the Geochang SLR station is large enough. In this paper, through orbit simulations, the characteristics of variation of the angular distance between the two satellites is analyzed to figure out the time slots when laser ranging is allowed.

• Journal of the Korea Society for Simulation
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• v.19 no.4
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• pp.123-128
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• 2010

The space radiation/total ionizing Dose(TID) and its effects, and the GEO satellite system design considerations in space radiation environment are studied in this paper using Spenvis(Space Environment Information System). The GEO satellite system in space environment is simulated by NASA AP8/AE8, JPL91 and NRL CREME models, repectively for trapped particle, solar proton and cosmic-ray. The total ionizing Dose which is accumulated continuously to spacecraft electronics has been expressed as the function of aluminum thickness. These values can be used as the criteria for the selection of electronic parts and shielding thickness of the Digital Channel Amplifier(DCAMP) structure.

• Aerospace Engineering and Technology
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• v.9 no.2
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• pp.22-30
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• 2010

KARI had integrated and tested GEO satellite in cooperation with Astrium Inc., France. In the middle of integration and test, It was necessary to check GEO satellite SA(solar array) status and require electrical interface verification with bus. SA of GEO satellite have different mechanical characteristics in comparison with those of LEO satellite which was tested in KARI. LEO SA has been deployed by simple mechanical hinge system but GEO SA has been done by more complicated method. so in this paper, we designed the test configuration and analyzed the test result of solar array electrical integration of GEO satellite.

• Aerospace Engineering and Technology
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• v.12 no.2
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• pp.40-47
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• 2013

GEO-KOMPSAT2 shall be designed to produce higher quality of image than that of COMS, and this requires the ground system to provide orbit data with high accuracy; better than 2km which is sort of high accuracy when it comes to geostationary satellite. For GEO-KOMPSAT2, KARI is planning to use ranging data for orbit determination, obtained from two ranging stations located in KARI and oversea country with long longitudinal baseline. This paper estimated achievable orbit determination accuracy using covariance analysis under assumption of using two ranging stations; SOC and available secondary tracking stations located in oversea countries. In addition to covariance analysis, in order to validate the analysis, the Monte-Carlo simulation has been performed and compared to the covariance analysis.

• Aerospace Engineering and Technology
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• v.4 no.2
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• pp.88-93
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• 2005

A conceptual study about the angle information based orbit determination technique for a geostationary satellite was performed. With an assumption that the simultaneous observing of the earth and nearby stars is possible, we confirmed that the view angles between the earth and stars can be use as inputs for orbit determination process. By the MATLAB simulation with least square method, the convergence is confirmed. This conceptual study was performed with the COMS for instance. This technique will be able to use as a back-up of ground station's orbit determination or a part of autonomous satellite operation.