• Title/Summary/Keyword: Transmission Angle

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Point Ahead Angle(PAA) Estimation and a Control Algorithm for Satellite-Pointing of the Ground Terminal in Satellite-to-Ground Optical Communication (위성-지상간 광통신용 지상단말기의 위성 지향을 위한 PAA 도출 및 제어 알고리즘)

  • Taehyun Yoon
    • Journal of the Korea Institute of Military Science and Technology
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    • v.27 no.3
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    • pp.329-337
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    • 2024
  • Free-space optical communication technology enables the high-speed data transmission and excellent anti-jamming security. We conduct research on satellite-to-ground free-space optical communication links for high-speed transmission of large-capacity surveillance and reconnaissance data. Since the satellite continues to move along its orbit while the optical signal is transmitted between the satellite and the ground, the pointing angle of the beam from the ground terminal needs to be corrected by Point Ahead Angle(PAA) so that the transmitted light reaches the expected location of the satellite. In this paper, we present the algorithm for PAA estimation and control.

A Development of V type Suspension String Set for UHV Transmission Lines (초고압 송전선로용 V련 현수애자장치의 개발)

  • Sohn H. K.;Lee H. K.;Keum E. Y.;Min B. W.;Choi J. S.;Choi I. H.
    • Proceedings of the KIEE Conference
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    • summer
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    • pp.497-499
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    • 2004
  • Due to a typhoon named MAEMI on Sep12, 2004, 7 transmission towers collapsed and 3 were damaged in the Gyeongnam and Busan areas. These caused long-term black-outs in Goeje-do. When a transmission tower collapses or is damaged, Construction will take more than 2 months and this will be accompanied by long-term black-outs. Therefore a temporary iron pole is used in such emergencies. Current temporary rehabilitation angle steel iron Pole consistes of around 800 members, 2,800 bolts and it takes about 5 days to construct a temporary transmission line. Consiquently wide black-outs occur during the construction of the temporary transmission line. To reduce black-out time, the construction period must be reduced as much as possible. This paper presents new methods to reduce temporary transmission line construction time to within 48 hours by applying a self-reliance assembling method instead of the current man power assembling method and by modulizing each angle steel with duralumin.

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Development of the Self-Build based Emergency Towers for Overhead Transmission Line (송전선로 비상복구용 자주조립식 철주 개발)

  • Byun Gang;Min Byeong Wook;Wi Hwa Bog;Park Jae Ung;Baek Soo Gon
    • Proceedings of the KIEE Conference
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    • summer
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    • pp.494-496
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    • 2004
  • Due to a typhoon named MAEMI on Sep12, 2004, 7 transmission towers collapsed and 3 were damaged in the Gyeongnam and Busan areas. These caused long-term black-outs in Goeje-do. When a transmission tower collapses or is damaged, Construction will take more than 2 months and this will be accompanied by long-term black-outs. Therefore a temporary iron pole is used in such emergencies. Current temporary rehabilitation angle steel iron Pole consistes of around 800 members, 2,800 bolts and it takes about 5 days to construct a temporary transmission line. Consiquently wide black-outs occur during the construction of the temporary transmission line. To reduce black-out time, the construction period must be reduced as much as possible. This paper presents new methods to reduce temporary transmission line construction time to within 48 hours by applying a self-reliance assembling method instead of the current man power assembling method and by modulizing each angle steel with duralumin.

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Estimation Algorithm of Receiver's Position and Angle Based on Tracking of Received Light Intensity for Indoor Visible Light Communication Systems (실내 가시광 무선 통신 시스템의 수신 광도 변화 추적 기반 단말기 위치 및 수신각 추정 알고리즘)

  • Hwang, Jun-Ho;Lee, Ji-Soo;Yoo, Myung-Sik
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.48 no.3
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    • pp.60-67
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    • 2011
  • Visible light communication system transmits data by controlling light emission of LED and receives data through photo detecter, which is considered as one of strong candidates of next generation wireless communication systems. The transmission capacity of visible light communication system depends on light intensity emitted from LED, sensitivity of PD, distance between transmitter and receiver, angle of incidence at the receiver. In particular, the receiver's vertical and horizontal movement changes distance between transmitter and receiver and angle of incidence, which may degrades transmission capacity of system. In this paper, we propose an estimation algorithm of receiver's position and angle based on tracking of received light intensity for indoor visible light communication systems. The performance evaluation of proposed algorithm confirms that the estimation algorithm of receiver's position and angle is quite important for visible light communication system to improve its transmission capacity.

Transmission Modeling and Verification for the Inverse Estimation of Electronic Warfare Threats (전자전 위협체 역추적을 위한 송수신 모델링 및 검증)

  • Park, So Ryoung;Jeong, Hoe Chang;Kwon, Jae Wan;Noh, Sanguk
    • The Journal of Korean Institute of Next Generation Computing
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    • v.13 no.4
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    • pp.112-123
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    • 2017
  • Research for the inverse estimation of RF threats and the efficient electronic attack based on the parameters of the electronic information has been active in the electronic warfare (EW) situations. In this paper, an EW transmission simulator is constructed from the modeling of radar threats, EW receivers, and propagation environments with the collected electronic information in order to verify the performance of the inverse estimation algorithm in various and practical EW situations. In simulation results, we show that the range tracking error and angle tracking error are produced within ten meters and one degree, respectively. And also, we show that the changing relations between the angle tracking error and the parameters of the monopulse angle tracking radar such as the beamwidth and squint angle in simulation results correspond with those in the theoretical modeling. Accordingly, the constructed EW simulator can be used to observe the modifying characteristics of the electronic information in transmission environments, and then, to evaluate the performance of the inverse estimation system in various EW situations.

Frequency translation approach for transmission beamforming in FDD wireless communication systems with basestation arrays (기지국 안테나 배열을 이용한 FDD 방식의 무선통신 시스템에서 송신 빔 형성을 위한 주파수 변환 방식)

  • ;Shawn P.Stapleton
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.34S no.5
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    • pp.1-14
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    • 1997
  • We consider transmission beamforming techniques for frequency-division-duplex (FDD) wireless communication systems using adaptive arrays to improve the signal quality of the array transmission link. We develop a simple effective transmission beamforming technique based on an approximated frequency tranlsation (AFT) to derive the tranmsiion beamforming weights from the uplink channel vector. This technique exploits the invariance of the short-time averaged fast fading statistics to small frequency translations. A simple approximate relationship that relates the transmission channel vector to the reception channel vector is derived. We have developed its practical alternative in which the frequency translation of the channel vector is performed at the principal angle of arrival (AOA) of the u;link synthestic angular spectrum instead of the mean AOA. To analyze the performance of the proposed methods, we consider the power loss incurred by applying the estimated channel vector instead of the true downlink channel vector. The performance is analyzed as a function of the mean AOA, the angular spread, the number of elements, frequncy difference between the uplink and the downlink, and the angle distribution. Their performance is also compared with that of the direct weight reuse method and the AOA based methods.

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A Study on the Transmission Error of a Star type Epicyclic Gear Train (스타형 유성기어열의 전달오차에 관한 연구)

  • 류형태;이동환;천길정
    • Transactions of the Korean Society of Automotive Engineers
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    • v.7 no.5
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    • pp.206-212
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    • 1999
  • In this paper, the transmission error of a atar type Epicyclic Gear Train (EGT) has been studied. Dynamic analysis has been executes calculate the rotation angle of the input and output shafts at various loads. Transmission Error of EGT has been measured to compare with the analysis results. There are qualitative similarity between the experimental and analytical results.

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Estimation of Mutual Inductance Angle for 2-D Wireless Power Transfer System (2차원 무선전력전송 시스템의 상호 인덕턴스 각 추정)

  • Guo, Tianqi;Seol, Won-Kyu;Chung, Se-Kyo
    • Proceedings of the KIPE Conference
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    • 2017.11a
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    • pp.49-50
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    • 2017
  • In a two-dimensional wireless power transfer system, the mutual inductance angle is the most important parameter for determining the power transmission efficiency. This paper presents a technique to estimate the mutual inductance angle from the voltage and current information of the transmitting (Tx) coils. The equation to estimate the mutual inductance angle is derived, and the validity of the proposed method is verified through simulation and experiment.

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Analysis Performance of VLC System according to the Transmission Distance and Angle of Incidence (전송 거리 및 입사각에 따른 가시광 통신 시스템 성능 분석에 관한 고찰)

  • Kim, Gyun-Tak;Han, Doo-Hee;Lee, Kye-San;Lee, Kyu-Jin
    • Journal of Convergence Society for SMB
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    • v.4 no.4
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    • pp.37-42
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    • 2014
  • In this paper, we analyzed the main factors that affect the performance in Visible Light Communication (VLC) system. Generally, published papers of VLC system have been studies to focus on increased data rates, transmission distance and modulation scheme. Therefore, in order to analyze detailed environment for VLC system, we was performed to analyze the performance of a major impact on the VLC system according to communication distance and the angle of incidence. The computer simulation results show that the performance attenuation was confirmed.

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