• Bulletin of the Korean Space Science Society
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• 2004.10b
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• pp.58-58
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• 2004

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.229-231
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• 1994

For the effective use of satellite communication transponder, tests for the payload system such as IOT(In-Orbit Test), RPM(Routine Payload Monitoring), CSM(Communicatios System Monitoring), and REV(Remote Earth-Station Verification) have to be conducted. Those tests are used in order to verify the condition and generic design of the satellite, to provide a database for operational calculations, and to maintain the quality of communication services. As the satellite communication system gets with wider expansion with higher complexity of operation, tests for the communication system also need more complex operation that usesophisticated computer-controlled measuring system. For and C language based measurement functions, which uses GPIB protocol and SCPI commands. But SICL requires knowledge of BASIC and C language as well as GPIB and SCPL system. This paper introduces a new language called CALSTEP-Control and Access Language for the Systems of Test Equipment and Payload. This language is designed for the operator to perform the tests for the satellite communication system without any special knowledge that is mentioned above. This language has very limited number of commands which are to be used to control the payload system and test equipments to perform IOT and CSM, and those commands are very readable and easy to understand, so an operator without any knowledge of BASIC and C programming language, or SICL and SCPI command can use it.

• Journal of Astronomy and Space Sciences
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• v.17 no.2
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• pp.249-256
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• 2000

It has been developed to calculate fuel budget for a geostationary communication and broadcasting satellite. It is quite essential that the pre-launch fuel budget estimation must account for the deterministic transfer and drift orbit maneuver requirements. After on-station, the calculation of satellite lifetime should be based on the estimation of remaining fuel and assessment of actual performance. These estimations step from the proper algorithms to produce the prediction of satellite lifetime. This paper concentrates on the fuel estimation method that was studied for calculation of the propellant budget by using the given algorithms. Applications of this method are discussed for a communication and broadcasting satellite.

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.218-223
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• 1994

On the satellite communication system, conventional key issues of control have been focused on the attitude and orbit control, monitoring and control of communication payload such as IOT(In-Orbit-Test) and CSM(Communication System Monitoring) and so on. As the vulnerabilities are being increased on the satellite communication network, security services are required to protect it against security violated attacks. In this paper, a security architecture for satellite communication network is presented in order to provide security services and mechanisms. Authentication protocol and encryption scheme are also proposed for spacecraft command authentication and confidentiality.

• Journal of Astronomy and Space Sciences
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• v.17 no.2
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• pp.257-266
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• 2000

A satellite RF communication link is analyzed based on a simple fundamental equations by systematic approach in this paper. The number of variables related to a design and analysis of satellite RF link is often a dozen or more, thus it is a tedious and time-consuming task. With the given input data, the important parameters are calculated step by step and three communication characteristics such as communication channel capacity, carrier-to-noise ratio(CNR) at the satellite and ground station are analyzed. It gives very useful information to the system engineers for designing and analyzing the overall satellite communication system in the conceptual design phase.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.180-183
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• 1997

In this paper, we present the Tele-consulting system of radiology, which uses the communication network as asymetric satellite data communication system. The asymetric satellite data communication system uses receive-only satellite links or data delivery and PSTN(Public Switched Telephone Network) modem or N-ISDN(Integrate Services Digital Network) for communication. The satellite communication linking shows the very high-speed performance than 28.8kbps modem linking. The satellite linking is 5 - 10 times aster than the modem linking. Consequently, we get the conclusion that our system is suitable or tele-radiology and telemedicine.

• Journal of Satellite, Information and Communications
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• v.7 no.1
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• pp.102-107
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• 2012

In this paper, we presented interference scenarios and an evaluation methodology for the co-frequency radio interference between a multi-beam mobile satellite communication system and a mobile communication system in 2.1 GHz band. Radio interferences between these systems are calculated using a minimum coupling loss method and an assesment for minimum separation distances was conducted for coexistence of a mobile satellite system and a mobile system in the same geographical area.

• Journal of Astronomy and Space Sciences
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• v.37 no.1
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• pp.11-18
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• 2020

Satellite optical communication has gained significant attention owing to its many quality features (e.g., a larger bandwidth, license free spectrum, higher data rate, and better security) compared to satellite microwave communication. Various experiments have been performed during many space missions to demonstrate and characterize inter-satellite links, downlinks, and uplinks. Korea has also planned to establish an experimental communication system using a geostationary earth orbit (GEO) satellite and the Geochang station as an optical ground station for low Earth orbit (LEO)-to-ground optical relay links. In this study, the performance of inter-satellite communication links and downlinks was investigated for the new Korean experimental communication system in terms of link margin, bit error rate (BER), and channel capacity. In particular, the performance of the inter-satellite links was analyzed based on the receiving apertures and the transmitting power, while that of the downlink was analyzed in terms of atmospheric turbulence conditions and transmitting power. Finally, we discussed two system parameters of receiving aperture and transmitting power to meet the three criteria of link margin, BER, and channel capacity.

• Journal of Astronomy and Space Sciences
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• v.20 no.4
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• pp.313-318
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• 2003

A communications satellite system placed in three-Lagrange points, $L_3$, $L_4$ and $L_5$, of the restricted three-body problem in Earth-Moon system is proposed in this paper. LEO satellite constellation has been another choice of communications system. The proposed system which is alternatives of limited geostationary orbit resources, has some weak points such as long distance from the Earth, relatively expensive launch cost, long delay time, more required power, and so on. It has good points like less efforts (fuel) for station keeping, less eclipses, etc. This system has limitations for applications to provide commercial services but it is still some attractive points.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.45-48
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• 2007

COMS satellite is a multipurpose satellite in the geostationary orbit, which accommodates multiple payloads of Meteorological Imager, Geostationary Ocean Color Imager and Ka band Satellite Communication Payload in a single spacecraft platform. In this paper, current status of Korea's first geostationary Communication, Ocean and Meteorological Satellte(COMS) program development is introduced. 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 system design difficulties are in the different kinds of payload mission requirements of communication and remote sensing purposes and how to combine them into a single satellite to meet the overall satellite requirements. The COMS satellite critical design has been accomplished successfully to meet three different mission payloads. The platform is in Korea, KARI facility for the system integration and test. The expected launch target of COMS satellite is scheduled in June 2009.