• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.2 s.332
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• pp.9-16
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• 2005

The performance of satellite range measurement using tone method was analyzed in the presence of satellite link AWGN. The phase errors in range measurement are generated by AWGN of satellite up- and down-link and the degradations of satellite range measurement are dependent on the transmission mode and loop bandwidth of satellite measurement system. The analyzed effects for satellite measurement in presence of satellite link noise were also analyzed with the measured satellite range data via satellite range measurement system operating in satellite link AWGN. In RAU mode, the satellite range differences of 14.4 to 40.6 m were occurred according to the loop bandwidth of satellite range measurement system and the degradation of 0.3 dB compared with theoretical value was generated under condition of the signal-to-noise ratio of 43 dB. In RAU and TM mode, the performances of range measurement were approximately agreed to the that of RAU mode. In order to get the equal performance characteristics with RAU mode, the signal-to-noise ratio of satellite link for RAU and TM mode should be increased by signal power of 2.3 dB, which is a power loss due to transmission of telemetry signal.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5A
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• pp.641-650
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• 2000

The effects of noise and doppler for low orbit satellite range measurement using tone method are represented in this paper. Also the optimal noise bandwidth of range signal detection circuit which is used for range measurement system of KOMPSAT is proposed. Based on the effects of satellite orbit parameters via the deduction of dynamic motion characteristics of low orbit satellite and signal to noise spectral density of range measurement signal, the effects of noise and doppler for range measurement system are analyzed. The effect of satellite link noise is decreased, but the effect for doppler is increased as the PLL noise bandwidth of range signal detection circuit is increased. The validation of analyzed effect is verified via comparison of measurement results of KOMPSAT's range measurement system and simulation results in environments of low orbit satellite.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.11
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• pp.1084-1094
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• 1991

Upon introducing satellite communication system to korea, one of the important problems to copy with is the effect from the probable intentional interference i. e. jamming. In this paper, we have considered the M any PSK signal and the soft limiter type, which contains hard limiter, nonhnear satellite transponder in environments of uplink tone or noise jamming plus Gaussian noise and downlink Gaussian noise. Using the derived error rate equation, we have evaluated numerically the error performance of BPSK and QPSK system, and shown in figures in terms of upink and downink earner to jamming rater(CJR) and limiting level. From the results we have known that tone jamming effect on the error performance in BPSK and QPSK signals in nonlinear satelhie shnnel become less with increasing the uplink CNR and with decreasing the liniting level. And in a tone jamming, the limiting level affects hardly on the error performance of both BPSK and QPSK signals. When limiting leveri is zero, BPSK and QPSK signals show the best error rate performance.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.163-166
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• 1998

Toen 방식을 사용하는 거리 측정시스템의 잡음 및 간섭에 대한 열화 도를 분석한다. 위성 링크상의 잡음 및 다중 변조 방식에 의한 전송 신호간 간섭들로 인하여 위상차 측정에 열호가 발생하며, 열화 도는 ranging 측정 시스템의 잡음 대역폭에 의존한다. Ranging 측정 모드에서는 잡음 대역폭 8Hz, 4Hz 그리고 1Hz에 대하여 0.3dB 열화가 방샐하였으며, ranging 및 원격 측정 데이터 전송 모드에서는 대역폭에 따라 6.4dB, 4.2dB, 4dB가 발생하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.10
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• pp.1831-1836
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• 2016

Phase noise spectrum distributions of signal generators for next-generation VSAT satellite system based on DVB-RCS2 were analyzed in this paper. The forward link of VSAT system utilizes the APSK higher-order modulation methods based on the DVB-S2 ACM, the modulation methods of the return link utilizes the higher-order PSK and QAM based on the DVB-RCS2. In digital satellite system using the higher-order modulation techniques, the phase noise have an effect on transmission performance, the transmission performance is dominantly degraded by the phase noise of signal generators in the transmission system. The phase noise spectrum distribution of signal generators are analyzed by considering the ACM conditions that adopts the modulation techniques and data rates due to satellite transmission environment. The proper phase noise spectrum distribution for next-generation VSAT system based on DVB-RCS2 are proposed from the analyzed phase noise spectrum characteristics.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.6
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• pp.489-496
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• 2021

The X-band frequencies for transmitting the data from earth observation satellites are limited, so a number of satellites share the frequency bands. In order for multiple satellites to utilize same or adjacent frequency bands, International Telecommunication Union - Radiocommunication (ITU-R) limits power flux density (PFD), which overcomes the interferences among multiple satellites. However, even under the regulation, the interference effect needs to be analyzed when multiple satellites are connected to communicate with multiple ground stations (GSs) located close to each other. In this paper, the interference effect is analyzed based on signal to interference plus noise ratio (SINR) when two low earth orbit (LEO) satellites operating in different orbits are connected to communicate with randomly located two GSs in Korean peninsula. From the analysis results, it is confirmed that there can be interferences during 365 days operation even if the satellites meet PFD requirement, but the periods under interference effects are short and the interference can be foreseen.

• 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.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.7
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• pp.1180-1186
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• 2008

The LNB phase noise of user terminal for high data rate satellite transmission was analyzed in this paper. The phase noise severely affects the service performance in low data rate transmission as well as multi-mode signal for high data rate. As the satellite link frequency is increased, the effects of phase noise for multi-mode signal is increased. The phase noise of LNB, which is operated in high frequency band, is about equal to the transmission system phase noise and have an major effects on service performance degradation. The available transmission mode was analyzed in presence of phase noise of LNB and analysis method for LNB phase noise spectrum distribution was proposed in multi-mode signal.

• Journal of Aerospace System Engineering
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• v.16 no.6
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• pp.81-89
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• 2022

This study measured the radio environment of 10 domestic institutions with CubeSat ground stations for 24 hours in three frequency bands (VHF/UHF/S-band) allocated by the International Telecommunication Union (ITU). The impact of the RF environment around the ground stations on CubeSat downlink frequencies was analysed and compared with acceptable interference noise requirements from the CubeSat RF link. The findings indicate that not only the selection of downlink frequency but also the configuration of RF communication link design and ground station system of CubeSat should consider the S-band RF environment around the ground station due to the presence of several wireless devices.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12B
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• pp.1728-1735
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• 2011

In this paper, satellite data link waveform is proposed which is based on the waveform of Link-16 but LDPC code is studied instead of CCSK code in order to be optimized to satellite nonlinear channel environment and transmission characteristics. And the DSM (Demux, Selective CH switch, and Mux) transponder structure is suggested which can remove all of the jamming signal out of the transmission signal band and convert uplink hopping frequency to desired ones of downlink. The results of BER and anti-jamming performance analysis shows that the required Eb/No and processing gain in the worst case partial band jammer of the proposed waveform are 2.5dB and 52dB respectively and the anti-jamming capacity improvement of DSM transponder is maximum 2dB.