• Title/Summary/Keyword: Mobile Satellite Control

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An Improvement of Performance in a Satellite Antenna Tracking Control System for Mobile DAB Reception (DAB수신을 위한 이동체용 위성 안테나 트랙킹 시스템의 성능 개선)

  • Jeong Joong-Sung
    • Journal of Advanced Marine Engineering and Technology
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    • v.28 no.7
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    • pp.1178-1184
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    • 2004
  • This paper presents the development of a satellite antenna tracking control system using a plane antenna for mobile DAB(Digital Audio Broadcasting) reception. To track more rapidly in the antenna of this system, this simple tracking system only tracks a direction of azimuth using pendulum in the direction of elevation. This system should track using the AGC(Automatic Gain Control) of the signal level which can receive DAB in spite of the changing of point and movement of the mobile. The directional gyro sensor is attached to solve the delay time in the Proposed tracking algorithm. The effectiveness of both the stabilization and tracking algorithm is demonstrated through experiment measuring AGC signal level. The implemented satellite antenna tracking control system is shown to be excellent for mobile DAB reception.

The Technique of Satellite Tracking and Beam Forming for Mobile TT&C (이동형 위성 관제를 위한 위성 위치 파악 및 빔 성형 기법)

  • Lee, Yun-Soo;Chinn, Yong-Ohk
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.18 no.12
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    • pp.1359-1369
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    • 2007
  • This paper describes the technique of satellite direction finding and main beam steering of the adaptive array antenna system which is used for mobile TT&C(Tracking Telemetry&Command) system. To be able to control the satellite on mobile vehicle while moving, the relative directional information of the satellite to the mobile vehicle is necessary to make main beam to the direction of satellite. To do this MUSIC, which is one of the super-resolution algorithm of wave direction finding, is used and then the performance analysis and quantization problem of phase shifter are addressed. This paper is valuable in the respect of showing feasibility of designing the moble TT&C using adative array antenna system.

Stabilization Control of line of sight of OTM(On-The-Move) Antenna (OTM 단말기 안테나 시선 안정화 제어)

  • Kang, Min-Sig;Cho, Yong-Wan
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.11
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    • pp.2073-2082
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    • 2010
  • The 4-th generation of mobile communication aims to realize global, fast and mobile communication service. The satellite communication charges a key role in this field. In this study, an OTM(On-The-Move) antenna which is mounted on ground vehicles and is used for mobile communication between vehicle and satellite was addressed. Since vehicles move during communication, active antenna line-of-sight stabilization is a core technology to guarantee high satellite communication quality. Stabilization of a satellite tracking antenna which consists of 2-DOF gimbals, an elevation gimbal over an azimuth gimbal, was considered in this study. Various disturbance torques such as static and dynamic mass imbalance torques, variation of moment of inertia according to elevation angle, friction torque related to vehicle motion, equivalent disturbance torque due to antenna roll motion, etc. were analyzed. As a robust stabilization control, rate feedback with sliding mode control and position feedback with proportional+integral control was suggested. To compensate antenna roll motion, a supplementary roll rate feed forward control was included beside of the feedback control loop. The feasibility of the analysis and the proposed control design were verified along with some simulation results.

Performance of a Satellite Tracking Antenna Control System for Mobile DBS Reception (차량용 DBS 수신을 위한 위성 추적 안테나 제어시스템의 성능 구현)

  • Kim, Dong-Cheol;Min, Gyeong-Sik;Arai, Hiroyuki
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.39 no.4
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    • pp.216-224
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    • 2002
  • This paper describes a performance of a satellite tracking antenna control system for mobile DBS reception. In order to improve the tracking speed and the stability of this system, a directional sensor function is added to a conventional left-right tracking algorithm. The satellite tracking experiments of the fabricated antenna system for the DBS reception were performed at a highway and an urban area. The measured AGC signal level on the highway was observed above the level to watch television. Therefore, an excellent performance of the hardware system with the tracking algorithm compensated for the directional sensor was confirmed.

Improvement of Channel Estimation Algorithm in Mobile/Satellite Communication Systems

  • Kim, Byung-Gi;Ryoo, Sang-Jin;Lee, Chang-Hun;Choi, Kwang-Seok;Kim, Seong-Hwan;Kang, Seong-Jun;Na, Cheol-Hun
    • Journal of information and communication convergence engineering
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    • v.7 no.3
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    • pp.404-411
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    • 2009
  • In this paper, in order to increase system capacity and reduce the transmitting power of the user's equipment, we propose an efficient power estimation consisting of a modified open-loop power control (OLPC) and closed-loop power control (CLPC) schemes for mobile/satellite communications systems. The OLPC works well if the forward and reverse links are perfectly correlated and the CLPC is sensitive to round-trip delay (RTD). Therefore, it is not effective in mobile/satellite system. In order to solve the above problem, we added monitoring equipment to both the OLPC and CLPC to use information about transmitting power that has not yet been received by the receiver over the satellite/ATC channel. Moreover, we adapted an efficient pilot diversity of both OLPC and CLPC in order to get a better signal to interference plus noise ratio (SIR) estimation of the received signal.

Performance of a Closed-Loop Power Control Using a Variable Step-size Control Scheme in a DS/CDMA LEO Mobile Satellite System (DS/CDMA 저궤도 이동 위성 시스템에서 가변 스텝사이즈 조절 방식 폐루프 전력제어의 성능분석)

  • 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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Improved Ultrasonic Satellite System for the Localization of Mobile Robots (이동로봇의 위치측정을 위한 개선된 초음파 위성 시스템)

  • Kim, Su-Yong;Yoon, Kang-Sup
    • Journal of Institute of Control, Robotics and Systems
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    • v.17 no.12
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    • pp.1240-1247
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    • 2011
  • The localization of mobile robot in environment is a major concern in mobile robot navigation. So, many kinds of localization techniques have been researched for several years. Among them, the positioning system using ultrasound has received attention. Most of these ultrasonic positioning systems to synchronize the transmitters and receivers are used for RF (Radio Frequencies). However, due to the use of RF, the interference problems can not be avoided and the performance of radio frequencies directly affects the positioning performance. So we proposed the ultrasonic positioning system without synchronizing RF. The proposed system is based on existing USAT (Ultrasonic Satellite System) adopted infrastructure transmitting type, and consists of transmitter and receiver synchronizing modules instead of the radio frequency transmitters and receiver. The ultrasonic transmitters and receivers are synchronized individually by the transmitter and receiver synchronizing modules. In order to calculate the bias between the transmitter and receiver synchronizing modules, new positioning algorithm similar to GPS was proposed. The positioning performance of the improved USAT without synchronizing RF and the validity of the proposed positioning algorithm are verified and evaluated by experiments.

Power Control Schemes for Land Mobile Satellite Communication Systems

  • Lee, Nam-Gil;Hwang, In-Tae;Kim, Seong-Hwan;Na, Cheol-Hun;Ryoo, Sang-Jin
    • 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).

A Study on PID Gain Auto Tuning for Steering Type mobile robot (조향형 이동로봇을 위한 PID 이득 자동 튜닝에 관한 연구)

  • Jung, Se-Young;Yang, Tae-Kyu
    • Journal of Satellite, Information and Communications
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    • v.11 no.4
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    • pp.39-43
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    • 2016
  • In this paper, we propose PID gain auto tuning method in steering type mobile robot. PID controller gain select method are various methods. Ziegler-Nichols step tuning method is one method tuning in PID controller. Use step tuning method find a the first gain and did experiment in steering mobile robot. and Make a new the second gains from the first gains. After appling the second gain in PID controller, Where perform observe for convergence time and stabilization error. Experiments result the second gain are useful in real steering mobile robot system.

Design of cellular, satellite, and integrated systems for 5G and beyond

  • Kim, Junhyeong;Casati, Guido;Cassiau, Nicolas;Pietrabissa, Antonio;Giuseppi, Alessandro;Yan, Dong;Strinati, Emilio Calvanese;Thary, Marjorie;He, Danping;Guan, Ke;Chung, Heesang;Kim, Ilgyu
    • ETRI Journal
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    • v.42 no.5
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    • pp.669-685
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    • 2020
  • 5G AgiLe and fLexible integration of SaTellite And cellulaR (5G-ALLSTAR) is a Korea-Europe (KR-EU) collaborative project for developing multi-connectivity (MC) technologies that integrate cellular and satellite networks to provide seamless, reliable, and ubiquitous broadband communication services and improve service continuity for 5G and beyond. The main scope of this project entails the prototype development of a millimeter-wave 5G New Radio (NR)-based cellular system, an investigation of the feasibility of an NR-based satellite system and its integration with cellular systems, and a study of spectrum sharing and interference management techniques for MC. This article reviews recent research activities and presents preliminary results and a plan for the proof of concept (PoC) of three representative use cases (UCs) and one joint KR-EU UC. The feasibility of each UC and superiority of the developed technologies will be validated with key performance indicators using corresponding PoC platforms. The final achievements of the project are expected to eventually contribute to the technical evolution of 5G, which will pave the road for next-generation communications.