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채윤경,조일인,임창훈,Yoon-Kyoung, Chae,II-In, Jo,Chang-Hoon, Im 통신위성우주산업연구회 2001 Joint Conference on Satellite Communications Vol.2001 No.-
본 논문에서는 이동 중에 차량에서 위성 방송뿐만 아니라 위성 인터넷을 수신함으로써, 각종 멀티미디어 서비스를 제공 받을 수 있는 이동 방송/통신위성 수신 안테나 시스템에 대하여 기술한다. 안테나는 시스템 전체 높이를 고려하여 $30^{\circ}$ 경사 빔을 갖는 한 쌍의 8x8 수평 편파 안테나를 사용하였다. 하나의 안테나 이득은 23.5 dBi이고, 전력 반치폭은 앙각 $11^{\circ}$/ 방위각 $8^{\circ}$이다. 안테나에 수신된 위성 신호는 빔 형성 블록에서 수신기 입력 신호와 추적 신호로 분리되고, 각각 독립적으로 주파수 하향변환된 후 수신기와 제어부로 전달된다. 개발된 안테나 시스텡은 앙각 방향 대해서 $45^{\circ}$$\pm$$5.5^{\circ}$의 추적 범위를 갖고, 방위각 방향에 대해서 $360^{\circ}$전방위 추적을 수행한다. 방위각 방향 추적 방식은 전자적 순차 빔 비교에 의한 기계적 추적 방식이다. 추적 속도는 $60^{\circ}$/sec이고, 추적 손실은 0.5dB로 양호한 특성을 얻었다. 개발된 안테나 시스템의 field test 결과, 방송위성 수신시 C/N = 13.5 dBi, 통신위성 수신시 C/N = 12.5 dBi로 양호한 특성을 얻었다. This paper describes mobile DBS/CS receiving antenna system which receives satellite broadcasting and satellite internet on the way of moving. With the antenna system, various kinds of multimedia service can be provided from satellite. A couple of horizontally polarized 8x8 Yagi-like patch array antenna with $30^{\circ}$ squinted beam has been used in consideration of the height of the whole antenna system. The gain of each antenna is 23.5dBi and it has HPBW of $11^{\circ}$ elevational angle and $8^{\circ}$ azimuthal angle. The receiving signal at antenna is divided between input signal and tracking signal at beam forming block. The each divided signal is transmitted to correspondent down converter set-top box or control unit. The developed antenna system has the tracking range of $45^{\circ}$$\pm$$5.5^{\circ}$ in the direction of elevation angle and $360^{\circ}$ in the direction of azimuth angle. The mechanical tracking method so called electrically sequential lobe comparison method has been adopted to trace azimuth angle. The tracking speed is $60^{\circ}$/sec and the loss during tracking is 0.5d8. Field test has been performed to measure the quality of the developed antenna system. The test result showed C/N of 13.5dB when receiving BS and 12.5dB when receiving CS.
남현도,조일인 단국대학교 1998 論文集 Vol.33 No.-
Conventional PID gain-tunning methods such as a Zigler-Nichols method and the relay feedback method, have many problems, so the optimal controller’s gains should be tuned by using try and error methods. In this paper, modified PID-type controllers which include self-tunning characteristics are pro-posed. Proposed controllers automatically tune the PID gains using neural network, and neural network compensators in proposed controllers have the robust properties against presence of disturbance. A modified learning scheme was also proposed for improving learning speed in neural networks and satisfying the real time condition. Computer simulation were performed to show the usefulness of proposed controllers in case of brushless DC motor control. As shown in result of computer simulations, proposed controllers have good performances and robust properties even though disturbance exists.