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Rhee, Seung-Wu;Kim, Zeen-Chul
- 제어로봇시스템학회:학술대회논문집
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- 1998.10a
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- pp.53-57
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- 1998
Star tracker placement configuration is proposed and the properness of the placement configuration is verified for star tracker's sun avoidance angle requirement. Precision attitude determination system is successfully designed using a gyro-star tracker inertial reference system for a candidate LEO spacecraft. Elaborate kalman filter formulation for a spacecraft is proposed for covariance analysis. The covariance analysis is performed to verify the capability of the proposed attitude determination system. The analysis results show that the attitude determination error and drift rate error are good enough to satisfy the mission of a candidate spacecraft.
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Park, Jun-Oh;Jang, Won-Kweon;Kim, Seong-Hui;Jang, Hong-Sul;Lee, Seung-Hoon
- Journal of the Optical Society of Korea
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- v.15 no.3
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- pp.278-282
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- 2011
We discuss two possible optical noise sources in an electro-optic camera loaded on a low earth orbit satellite. The first noise source was a reflection at the window for signal rays incident upon the window which is placed before the FPA plane. The second noise source came from a reflection at the surface of the FPA cell when the signal flux is not entirely absorbed. We investigate the noise generation processes for two optical noise sources, and a parametric solution is used to estimate the optical noise effects.
https://doi.org/10.3807/JOSK.2011.15.3.278 인용 PDF KSCI

이해영
- Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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- 1998.05a
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- pp.177-186
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- 1998
In this paper, due to the congestion the radio spectrum, frequency bands are shared among the satellite communication system. Therefore for satisfactory we have to design and predict with reasonable accuracy the level of interference that might exist among them, Interference among the satellite communication systems depends on many factors such as climate, radio frequency, time percentage of interest, distance and path topography, propagation delay time. This paper suggest design method of Low-Orbit satellite communication and calculates the field-of view of satellite, for the communication era using LEO. In addition, performs performance evaluation on the basis of link margine.
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전동근;이연우;홍선표
- The Journal of the Acoustical Society of Korea
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- v.19 no.1
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- pp.16-24
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- 2000
In this paper the performance of a closed-loop power control scheme using variable step size decision method for DS/CDMA based-low earth orbit(LEO) mobile satellite systems in which the long round trip delay is a dominant performance degradation factor is evaluated. Because there are fundamental differences in the characteristics between the LEO mobile satellite channel and terrestrial mobile channel, such as long round trip delay and different elevation angle, these factors are considered in channel modeling based on the European Space Agency(ESA) measurement data. Since the round trip delay (from the mobile terminal to the gateway station via satellite) is typically 10∼20ms in low altitude satellite channels, closed-loop power control is much less effective than it is on a terrestrial channel. Thus, the adaptive power control scheme using a variable step size control is essential for overcoming the long round trip delay and fading due to the elevation angle. It is shown that the standard deviation of signal to interference ratio(SIR) adopting a variable step size closed-loop power control scheme is much less than that of a fixed step size closed-loop power control. Furthermore, we have driven the conclusion that the measurement interval of power control commands is optimal choice when it is twice the round trip delay.
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