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一、引言 卫星上行站对发射天线的指向精度要求很高,C波段天线要达到±0.01°。2007年底我站9米主用RSI-100天线控制系统出现故障,表现为每次开机进入系统的时间越来越长,最终就彻底无法进入控制系统界面。我站人员用RSI公司随设备提供的软盘版软件引导进入系统,但控制界面显示乱码,没法正常使用。 相似文献
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为保证远端站卫星天线能够时刻对准卫星,中国移动应急通信网络的抗灾超级基站采用的小口径固定站天线采用了一种全新的自动寻星方案.该自动寻星天线系统在普通小口径固定站手动卫星天线的基础上,借鉴大口径电动天线、车载静中通、便携式卫星天线的传动系统及伺服控制的经验,通过改变天线传动系统和定制伺服控制系统来实现自动寻星功能,同时又... 相似文献
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为满足中继卫星系统对天线指向精度的要求,首先描述了天线指向控制概念,对用户星与中继卫星星间链路的建立过程进行了分析,并且设计了星上自主控制方案,在Simulink环境下对所设计的天线指向控制系统进行了数学仿真,最后通过对仿真结果的分析验证了用户星天线控制系统的跟踪性能。 相似文献
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金立希 《卫星电视与宽带多媒体》2014,(7):62-65
一直以来,卫星天线除雪问题一直是困扰地球站安全播出的重要课题。本文重点介绍了浙江广播电视卫星地球站贴膜式电加热天线除雪系统改造工作, 相似文献
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(上接2008年第07期)5天线控制器由于太空环境存在多种干扰因素,而卫星控制系统并非尽善尽美,实际同步卫星相对于地球是有缓慢的微小运动的。如果电视接收站天线不能始终对准卫星,接收信号便会忽强忽弱,甚至丢失信号——卫星跑到天线波束外面了。天线控制系统的主要任务,就是跟踪卫星位置的漂移变化,实时调整天线指向,保证最佳的接收效果。 相似文献
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由于移动卫星通信系统中的车载站在通信过程中是运动的,因此存在卫星功率有限、传输高速业务与移动站低天线增益之间的矛盾;系统有时是在非高斯信道中工作的,电波传播情况复杂;地面终端的天线时刻对准所使用的卫星。对如何利用有限的卫星功率条件,在地面终端的快速移动中,实时传输宽带多媒体业务,涉及卫星的带宽和功率、移动终端能力、天线伺服跟踪等相关问题进行了讨论,给出了设计原则和设计思路。 相似文献
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基于AET座架的遥感跟踪伺服系统设计 总被引:1,自引:0,他引:1
在车载遥感站设备中,跟踪伺服控制系统是其重要组成部分。论文介绍了车载极轨卫星遥感站天线跟踪伺服系统的工作原理、系统构成等,给出了基于AET座架过顶跟踪伺服控制系统的控制策略及坐标转换公式。最后给出了系统实际跟踪卫星的跟踪结果。实际应用表明,该伺服控制系统方案设计合理.运行稳定,具有良好的动态跟踪性能。 相似文献
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Activities since August 1989 are covered. Included are antennas for mobile communication, multibeam earth station antennas, satellite-borne antennas for communication, and for earth remote sensing, direct broadcast satellite antennas, and propagation studies for land mobile radio, mobile satellite systems, fixed satellite systems, and terrestrial propagation 相似文献
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An 11.5 m 30/20 GHz band Cassegrain antenna has been developed for a Japanese domestic satellite communication system earth station. In order to form an economical satellite communication network, the earth station antenna is required to be installed on the top of a telephone office building in a large city. Therefore, interference with terrestrial radio relay systems and antenna load on a building become the most important problems to be investigated. Considering the satellite position in geostationary orbit, a limited steerable system combined with a two-jackscrew drive mechanism is employed to lighten and simplify the antenna structure. Measured antenna aperture efficiencies are 72% in 20 GHz band and 68% in 30 GHz band. Measured wide angle radiation patterns satisfy the CCIR recommendation level. TheG/T of the antenna at the feed horn port is measured to be 53.9 dB/K atEl = 45deg at 18.75 GHz. Interference with the 20 GHz band terrestrial radio relay system in extremely near field was experimentally studied. Results show that the terrestrial system's antennas can be installed closely up to about 20 m without serious interference. 相似文献
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The transmission capacity which can be provided by a geosynchronous multiple-beam satellite employing frequency reuse is studied. Like all communication channels, satellite capacity is limited by available power, transmission bandwidth, and noise. In addition, factors peculiar to satellite links include cochannel interference among neighboring beams, channel nonlinearity, nonuniformly distributed traffic, and for satellites operating at frequencies above 10-GHz, rain attenuation. The effects of these factors upon the capacity of a satellite system are examined in detail. Results for a 12/14-GHz system with assumed satellite parameters compatible with a space shuttle launch and small 5 m earth station antennas show that a capacity of about 30 Gbit/s can be provided if the unavailability due to rain outage is no greater than 0.1 percent, and that about 10 Gbit/s can be provided for an unavailability no greater than 0.01 percent. Efficient utilization of the geosynchronous arc is also explored, and current trends in communication satellites are discussed. 相似文献
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90年代以来,卫星移动通信发展异常迅速。许多科研组织都对移动地面站中的电扫描阵列天线进行了研究。介绍了目前已经开发并应用于卫星移动通信的几种电扫描阵列天线及其技术细节。 相似文献
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Offset reflector antennas have advantages for communication systems because they are not severely subject to blocking. Difficulties mainly arising from structual asymmetries have inhibited the realization of an offset reflector antenna with a large aperture for commercial use. This paper describes the design of an offset Cassegrain earth station antenna for the Japanese domestic satellite communication system. Antenna measurements showed 76 and 69 percent aperture efficiencies at 20 and 30 GHz, respectively, less than -20 dBi wide angle directivity and an 18 K noise temperature in operating conditions. Performances are far superior to conventional axisymmetrical earth station antennas. The antenna was reassembled on a telephone office building after the measurements. The antenna gain was reconfirmed there, using the sun as a radio frequency source. Experiments show that the earth station antenna and a terrestrial antenna can be placed on the same building without serious interference. 相似文献
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《Electronics & Communication Engineering Journal》1991,3(6):243-251
An experimental microterminal satellite data communication system known as CODE has been developed by the European Space Agency with support from universities, research organisations and industry. The system, which operates at Ka band, consists of a large number of microterminals with 80 cm diameter antennas which can communicate directly in a mesh network at 64 kbit/s. A central hub station is used for channel allocation and for general monitoring and control of the microterminals. The system supports a wide range of standard application software which can run on standard personal computers and workstations. The design rationale of the system is described together with some of the applications and demonstrations that have been transmitted over the Olympus satellite to date 相似文献
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Falk G. Groff J. Milliken W. Nodine M. Blumenthal S. Edmond W. 《Selected Areas in Communications, IEEE Journal on》1983,1(6):1076-1083
The Wideband (packet satellite) network is an experimental 3 Mbit/s communications system developed under sponsorship of the Defense Advanced Research Projects Agency and the Defense Communications Agency. This system is being used to evaluate the use of packet transmission for efficient voice communication, voice conferencing, and integration of voice and data over a satellite channel. Each station in the Wideband network consists of an earth terminal (dedicated 5 m antenna plus associated IF/RF equipment), a burst-modem and codec unit, and a station controller. Station controllers provide interfaces to host computers (including packet speech sources) and manage the allocation of the satellite channel on a TDMA demand-assigned basis. TDMA demand-assignment is implemented using a reservation-based packet-oriented protocol capableof handling traffic at multiple priority levels. The channel protocol provides a reservation-per-message mode of service (datagrams) to support transmission from bursty traffic sources and a reservation-per-call mode of service (streams) to support traffic with more regular arrival statisticS (e.g., vioce). A distributed scheduler running in every station controller eliminates the need for a central control station and minimizes network transit delay for datagram transmission as well as stream creation, modification, and deletion. In this paper we describe the protocols and mechanisms upon which the Wideband packet satellite network is based. 相似文献
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本文系统总结了地球站天线INTELSATM网的最新技术要求,阐述了地球站天线指标的发展趋势,指出了现代卫星通信地球站天线设计研究的方向。 相似文献