• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.525-528
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• 2003

This paper describes the effective and rigorous analytic method of multipath effect which results from insufficient isolation characteristics between adjacent channels in communication payload system. It is very important to analyze the multipath effect for verifying the performance of transponder subsystem that especially is consist of multi channels. Finally the multipath effect are analyzed by calculating the GR and GDR for two adjacent channels of Ku-band transponder subsystem on the Communication & Broadcasting Satellite(CBS).

• Journal of information and communication convergence engineering
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• v.7 no.1
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• pp.78-85
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• 2009

In order to increase system capacity and reduce the transmitting power of the user's equipment, we propose an advanced power control scheme consisting of a modified open-loop power control (OLPC) and closed-loop power control (CLPC) for land mobile satellite communication systems. The improved CLPC scheme, combining delay compensation algorithms and pilot diversity, is mainly applied to the ancillary terrestrial component (ATC). ATC link in urban areas, because it is more suitable to the short round-trip delay (RTD).

• Journal of Aerospace System Engineering
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• v.15 no.5
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• pp.113-128
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• 2021

In this paper, we present a simple ground receiving station as an educational method for a satellite system. Our system is produced similarly to the existing fixed ground station in terms of function by using satellite communication technology and related software commonly used in the amateur radio field. In addition, we conducted operation test to receive signals from operating satellites and confirmed the possibility of using them as a way to educate satellite systems, such as understanding ground station systems through satellite reception experience and satellite state information acquisition, and further designing satellite systems.

• Proceedings of KOSOMES biannual meeting
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• 2008.05a
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• pp.191-195
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• 2008

In Ansan (the headquarter of KORDI ; Korea Ocean Research & Development Institute), KOSC(Korea Ocean Satellite Center) is being prepared for acquisition, processing and distribution of sensor data via L-band from GOCI(Geostationary Ocean Color Imager) instrument which is loaded on COMS(Communication, Ocean and Meteorological Satellite); it will be launched in 2009. The basis equipment of KOSC(Electric power, Network, Security) has been constructed in 2007. KOSC is being constructed data processing and management system, GOCI L-band reception system, etc. The final object of KOSC is that maximize the application of GOCI.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.12
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• pp.1159-1164
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• 2016

This study describes the design and implementation of SHF band Low Noise Amplifier of Digital Satellite Communication. We have applied to HEMT part to minimize Noise Figure of system. and minimized the potential for the occurrence of such erroneous operation of equipment through the simulations of the space environment. We designed a reliable Low Noise Amplifier through simulation for a TID according to the vibration generated during the launch and space radiation environment, and compared pre-simulation of main performance results to test results about main performances of Low Noise Amplifier after production.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.9
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• pp.914-923
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• 2009

Helix antennas have been widely applied to satellite TT&C, data communication and GPS receiver systems onboard military, remote sensing and communication purpose satellites. The helix antennas are known to be convenient to control impedance and radiation coverage characteristics with a maximum directivity in satellite z-axis. Waveguide horn is commonly used for radar system that needs ultra-wideband pulse for exploration ground radar and electromagnetic disability measurement etc. It has high efficiency and low reflection characteristics provided by the low-profile shape and suppressed radiation distortion. In this paper, a waveguide horn structure incorporated with helix antenna design is proposed for satellite applications that require ultra-wideband pulse radar and high rate RF data communication link to ground station over wide coverage area. The main design concern is to synthesize variable beam forming pattern based on modified horn-helix combination helicone structure such that multi-mission antenna is implemented applicable for TT&C, earth observation, high data rate transmission. Waveguide horn helps to reduce the overall antenna structure size by introduction fold type reflector connected to the tapered helix antenna. The next generation KOMPSAT satellite currently under development requires high-performance precision attitude control system. We present an initial design of a hybrid hern-helix antenna structure suitable for efficient RF communication module design of multi-purpose satellite systems.

• Journal of Satellite, Information and Communications
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• v.4 no.1
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• pp.1-7
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• 2009

As the information age comes out, the aspect of future war brings about the many changes in terms of war-fighting environment. Accordingly, information superiority and intelligence-centric warfare have been important and new war-fighting concept such as NCW(network centric warfare) have been turned up. This paper proposed all-weather core-strategy communications systems guaranteeing not only the real-time transmission of the information collected in a battlefield and expansion, automation, and rapidity of a battlefield but also broadband, mobility, survivability, and flexibility. The proposed military satellite communications system is classified into wideband mass capacity link, survivability, and the system supporting OTM(on the move) communication for the real-time transmission of battlefield information. This paper analyzed the essential operation concepts and core schemes of the U.S. Army's next generation system, TSAT(Transformational Satellite Communication System). Base on the analysis results, this paper proposed that the architecture of next generation military satellite communications systems for NCW have to provide the data rate, anti-jamming capability, network control and management capability which are optimally adaptable for the wireless channel environments such as jamming and interference and to support the variety of platforms like high-speed mobile vehicles, micromini devices, super-high speed unmanned aerial vehicles. Finally, this paper also proposed that next generation military satellite communications systems need the technologies such as the adaptable multi-antenna, laser link, and next-generation anti-jamming waveform.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.12
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• pp.3030-3037
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• 2013

Life time of facilities is different In case of operating environment and frequency of use. So, the durable year of the facilities is only considered to replace the facilities at present. Thus, system management is needed economical assesment based on condition evaluation through performance analysis of facilities. This research makes a proposal for scientific condition evaluation table through physical assessment, performance analysis assessment, durable years assessment about satellite communication facilities being used in K-water. Consequentially, reasonable replacement plan is established for satellite communication facilities.

• Progress in Superconductivity
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• v.3 no.2
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• pp.178-182
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• 2002

Superconducting four-element patch array antenna was designed and fabricated using $high-T_{c}$ superconducting (HTS) thin film. The array antenna has single-feed circularly polarization and a resonance frequency of 11.85 GHz fur satellite communication system. To fabricate this antenna $YBa_2$$Cu_3$$O_{7-x}$(YBCO) superconducting thin films were deposited using rf-magnetron sputtering technique. Sequential rotation technique based on radiation elements($0^{\circ}$ , $90^{\circ}$, 1$80^{\circ}$, $270^{\circ}$ phase delay) was utilized to achieve circularly polarization. Simulated and measured results, the analysis on resonant frequency(fr), return loss, and bandwidth are presented. The results show that 10 dB return loss bandwidth of the array antenna is 11.04 GHz~12.59 GHz (13.15%) and 3dB axial ratio bandwidth is 11.42~12.52 GHz (9.2%).).).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.222-225
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• 2001

This paper describes design and performance test of dual-mode horn antenna for HAPS (High Altitude Platform Station) in 47.2 - 47.5 GHz and 47.9 - 48.2 GHz bands. To obtain the optimal geometry parameters of it. the conical section is represented by a stepped transition composed of a set of cylindrical waveguide sections. For each step. the corresponding generalized scattering matrix is calculated. The elements of the matrices at the open end of the horn, are calculated by the rigorous formulas of the factorization method. To verify the theoretical results, a horn breadboard was manufactured for the medium frequency of 47.7 GHz and its radiation beam patterns were measured. The calculated and theoretical results are in good agreement.