• Journal of Satellite, Information and Communications
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• v.1 no.1
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• pp.20-25
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• 2006

The link of Geostationary Communication Satellite has transit delay and noise environments by physical distance. This situation exerts an influence on the degradation of baseband performance of Earth Station. Therefore, it is very important that degradation of baseband performance is grasped previously. This paper is presented that developed the simulator which can evaluate the baseband performance of earth station of a military satellite communication system during the current development. The simulator can mock delay on a satellite channel and bit errors without being used actual satellite links.

• The KIPS Transactions:PartC
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• v.15C no.5
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• pp.409-418
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• 2008

In this paper, we programed the PPP(Point-to-Point Protocol) used in embedded application environments for Globalstar Satellite Modem. There are number of satellite communication systems such as Orbcomm, Globalstar, Inmarsat and etc. But each satellite data service have provided a communication interface only for their own data links. A data communication link is needed to communicate with Globalstar satellite service. Globalstar communication system uses PPP to establish data communication link, so we implemented the embedded processor based PPP protocol. The user terminal equipment also designed in this paper has various input/output devices and sensors applicable to any user specific application. The proposed PPP program works well with Globalstar data communication link through experimental tests.

• Journal of Satellite, Information and Communications
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• v.9 no.2
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• pp.58-62
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• 2014

This paper we introduce the satellite communication system consist of redundant central station with management module for increase the stability of the satellite link. Configuration of redundant central station in satellite communication system can minimize the service interruption due to unstable link or some module error. According to this, we expect to ensure efficient use of technology for the next-generation VSAT services and broadcasting services.

• ETRI Journal
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• v.24 no.1
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• pp.31-42
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• 2002

In high-speed multimedia satellite communication systems, it is essential to provide high-quality, economical services by using efficient transmission schemes which can overcome channel impairments appearing in the satellite link. This paper introduces techniques to compensate for rain attenuation and the Doppler shift in the satellite communication link. An adaptive transmission technique with a control algorithm to adaptively allocate transmission schemes is used as a countermeasure to rain attenuation. We introduce a new rain attenuation modeling technique for estimating system performance and propose a novel Doppler shift compensation algorithm with reduced hardware complexity. Extensive simulation results show that the proposed algorithm can provide greatly enhanced performance compared to conventional algorithms. Simulation software and hardware which incorporate the proposed techniques are also demonstrated.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.11 no.4
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• pp.15-31
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• 2001

In this paper we classify security threat elements of satellite communication into four parts; Level-0(satellite propagation signal), Level-1(satellite control data), Level-2(satellite application data) and ground network security level according to the personality and data of the satellite communication network. And we analyze each security levels. Using analyzed security threat elements, we divide security requirements into signal security level and information security level separately. And then above the existent signal security level countermeasure, we establish the countermeasure on the basis of information security policy such as satellite network security policy, satellite system security policy and satellite data security policy in information security level. In this paper we propose secure satellite communication network through the countermeasure based on information security policy.

• Journal of Satellite, Information and Communications
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• v.2 no.2
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• pp.69-74
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• 2007

Recently, the demands for the satellite broadband mobile communication services are increased. To provide these services, mobile satellite communication systems for the passengers or crews on the high-speed moving vehicles, are being developed for the last several years especially in the Europe and North America. However, most of these systems can provide only several hundred kbps of transmission rate and this is not enough performance to provide satellite internet service for the group users such as passengers on the high-speed train. Moreover, service availability with these systems is limited to be rather low because they don't have any countermeasure scheme for the N-LOS environment which happens often along the railway. This paper describes mobile broadband satellite communication system, which is on the development, to provide high data-rate internet services to the high-speed trains. This system is applied with the inter-networking scenarios of both satellite/terrestrial network and satellite/gap-filler network so that it can provide seamless service even in the train operating environment, and these inter-networking schemes result in high service availability. And this system also has the countermeasure schemes, such as upper layer FEC and antenna diversity, for the short fading which is occurred periodically on the railway due to the power supplying structures so that it can provide high speed internet services. Mobile DVB-S2 technology which is now being standardized in the DVB is used for the forward-link transmission and DVB-RCS for the return-link.

• Journal of Satellite, Information and Communications
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• v.8 no.4
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• pp.58-63
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• 2013

Since radio interference can degrade the performance of systems or limit the system operation, an accurate assessment of radio interference with the existing systems should be conducted prior to the operation of a new system. In this paper, we present an evaluation methodology for the radio interference between radio-navigation satellite service (RNSS) systems and mobile communication service (MS) system. Radio interferences from RNSS systems into MS system using minimum coupling loss (MCL) method are simulated and vice-versa, and the frequency sharing condition between two systems are derived in a same geographical area.

• Proceedings of the KSRS Conference
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• v.1
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• pp.356-359
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• 2006

The high prices and lack of information for satellite images prevent researchers from studying remote sensing and most non-professional people can't have the simple and easy solutions for the manipulation of satellite images. 'Satellite Imagery Information Management Center'(SIMC) project which is promoted by ETRI (Electronics and Telecommunications Research Institute) from 2002 to 2005 in Korea have the purpose to provide the satellite images freely to the public domain and the solutions for the above mentioned problems. Our project have the following five systems; Data Acquisition System, Data Preservation System, Integrated Solution System, Technology Development System, Operation Plan System. Data Acquisition System collects the satellite images such as LANDSAT, IKONOS, etc. Data Preservation System consists of database which registers the diverse satellite images. Integrated Solution System gives the user of public domain for the web service which search, order and transfer the satellite images. Technology Development System has the many processing technologies for the satellite images. Finally, the Operation Plan system has the role to plan the future of our SIMC project. In this paper, we will give the result of SIMC Project for each five systems during the fast four years from 2002 to 2005.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.147-150
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• 1998

To determine the satellite orbital positions under consideration of interference caused by inter-satellite systems is one of the most important issues in terms of optimal usage of satellite network resources. In this paper, we present the orbital positioning method for a new satellite to minimize inter-satellite system interference effect in the fixed satellite communication using a new method. Through the computer simulation, it is clear that the proposed method is suitable to determine the satellite orbital positions.

• Aerospace Engineering and Technology
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• v.7 no.1
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• pp.121-128
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• 2008

In the department of mobile communication technology and satellite communication technology, wireless communication technology division is very important by transmitting and receiving the signals in wireless link environment. Most of all, the components which comprises the transmitter and receiver can decide the RF(Radio Frequency) system performances. Therefore to assure the reliability in the satellite communication field, it is essential to acquire the competitiveness by developing the highly integrated and compact components by means of MMIC(Monolithic Microwave Integrated Circuit) technology. MMIC is the designing and fabricating technology for the RF components. This paper introduces the MMIC technology and describes the technological trend and prospect in the satellite application.