中国的卫星通信事业

卫星通信在我国的兴起 中国卫星通信技术的研究始于２０世纪 ６０年代,经过多年努力,８０年代在我国的主要城市建起了卫星通信地球站,并且成功地发射了自行研制的试验和实用卫星,使西藏、新疆通过卫星收看到中央电视台节目。随着改革开放的日益深入,卫星通信技术的应用在中国有如旭日喷薄而出,在国际国内通信、因特阿的构筑和广播电视等领域,扮演着不可替代的重要角色。 网络建设规模及效果 在固定卫星通信业务领域,中国北京、上海、广州以及各省省会、自治区首府等地,已建成四十多座属于国际卫星通信组织（Ｉｎｔｅｌｓａｔ）Ａ型…     

稀路由卫星通信系统

熊猫牌５５Ｂ００型稀路由卫星通信系统是南京无线电厂和南京通信工程学院、总参五十七所共同研制出的新一代卫星通信产品。本文介绍了该系统的技术特点、设备组成、网络监控管理的主要功能。     

便携式卫星通信地球站

便携式卫星通信地球站ＫａｚｕｎｏｒｉＴａｎａｋａ等一种体积小、重量轻的Ｋｕ频段卫星通信地球站已研制成功。这种地球站能用人工搬运和建立。由于它提供了ＩＳＤＮ接口，因此能提供多种业务，如视频和数据业务以及电话业务。本文介绍这种便携式卫星通信地球站的设备结...     

广东省卫星通信发展概况

卫星通信在当今电信业务中占非常重要的地位。本文以广州国际卫星通信地球站建成开通为例，简述了卫星通信的地面设备、开通方向、测试中的某些问题，并重点分析了ＩＤＲ与ＤＣＭＥ技术结合使用的前景。广东卫星通信发展迅速，国内卫星通信、国际卫星通信、ＶＳＡＴ和应急移动卫星通信四个层次同时并进。“九五计划”期间，通信电路计划突破五千条，除目前的广州国际、国内地球站和汕头卫星通信地球站外，争取筹建第四、第五个卫星地球站，卫星中继将成为个人通信的一部分。     

蓬勃发展的中国公众卫星通信

本文通过详细的统计数字，介绍了我国公众卫星通信发展现状及新的一年规划，剖析了国内其它卫星系统如移动卫星通信，农村卫星通信和ＶＡＳＴ的发展，并对我国２０００年前卫星通信的发展规划和策略进行了探讨。     

卫星通信地球站维护方式探讨

卫星通信近几年发展迅速,我国各个省都有卫星通信地球站,面对迅速发展的大好局面,如何维护好地球站的设备,使之更好地发挥作用,是各个卫星通信站维护部门所肩负的重大责任。在对福建省福州、厦门两个地球站的多年维护工作中,我们按维护规程进行维护,深刻体会到维护工作应突出维护重点和难点。对维护中易引起电路全阻的关键部位,要加强维护技术力量,并由此摸索出“抓两头带中间”的维护方式。从地球站设备组成的框图(图1)中可以看出,虽然设备多,但以一个地球站作为一个单元来讲,从信号传输的路由经过来看,地球站与外界有连接的仅是天线和光端…     

中国卫星通信的发展与展望

本文全面、详细地介绍了迅速发展中的中国卫星通信现状，展望了卫星通信的未来，指出竞争和管理是卫星通信市场健康、有序发展的关键。     

Ku-Band satellite data networks using very small aperture terminals—part II: System design

In this part of the paper on Ku-band VSAT networks, the issue of overall system design is considered. After discussing possible system architectures, primary attention is given to the star network configuration in which customer-premise VSATs communicate with a central hub station, co-located with, or terrestrially connected to a host computer. The component elements of a Ku-band star network for interactive data applications are discussed and the critical items from the point-of-view of performance, capacity and cost are identified. An analytical model for the network, which combines delay-throughput characterization of the multi-access inbound and TDM outbound channels with satellite link analysis is described. The analytical model is exercised over a range of typical system component, traffic model and performance objective scenarios to provide a set of general design guidelines. These guidelines are useful for evaluating the trade-offs between key system elements (channel access unit, modem, VSAT antenna and satellite), VSAT traffic message length parameters and the performance objectives (average and peak network response time and availability). The results are used to address the issue of multi-access protocol selection over a range of scenarios typical of 1.2 or 1.8m VSAT-based interactive networks using current commercial Ku-band satellites. The results show that interactive star networks are often limited by satellite power rather than bandwidth, so that the use of simple contention access for VSATs may not imply a significant system capacity penalty.     

Ku频段通信卫星转发器的发展

文中介绍了国外Ku频段通信卫星转发器的发展概况，讨论了Ku频段通信卫星转发器的两种体制及其实现的关键技术，为发展我国Ku频段转发器提供参考。     

中国卫星通信呼唤通信卫星

本文回顾了我国通信卫星技术的发展历程，介绍了目前通信卫星的应用概况。通过分析和比较，指出该领域中目前未来潜在的问题，并提出了建议。     

卫星通信的发展现状和趋势

随着通信的全球化发展，通信网络逐步向立体式综合化演变，卫星通信在其中扮演的角也越来越重要。     

频谱仪在卫星通信系统中的应用探讨

频谱分析仪广泛应用于微波技术领域,是在频域内对信号的电平、功率、频率等参数进行测量并显示的仪器,文章从频谱分析仪的原理出发探讨了其作为测试仪器在卫星通信中的应用.     

卫星移动通信系统的发展思考

本文回顾了现代中低轨道卫星移动通信系统的发展历程、在发展过程中存在的问题,全面分析了各行业、部门对卫星移动通信系统的使用需求,并展望未来发展前景,提出了未来卫星全球人个移动通信系统的发展策略。     

Ku-Band satellite data networks using very small aperture terminals—part I: Multi-access protocols

This two-part paper presents a comprehensive overview on the technology of very small aperture terminal (VSAT)-based satellite data networks, which have received increasing attention in recent years because of a combination of technical and economic factors. Ku-band networks with customer-premise earth-stations can overcome the inherent local access bottleneck in wide-area terrestrial data networks by suitably exploiting the unique multi-access and broadcast features of satellite communication. In this part of the paper, the issue of multiple access, which is an important critical path technology in the ongoing evolution of VSAT data networks, is considered in detail. Satellite multi-access protocols are classified in terms of channel synchronization (slotted and unslotted) and the qualitative nature of message access (fixed assigned, contention and reservation). In addition to well known techniques such as ALOHA, slotted ALOHA, tree CRA, packet CDMA and demand assigned (DAMA) TDMA, a number of new approaches to efficient unslotted access, including selective reject (SREJ) ALOHA, time-of-arrival CRA and locally synchronous reservation, are discussed. The general review is followed by a detailed performance comparison of a number of candidate first-generation VSAT protocols, namely ALOHA, slotted ALOHA, SREJ-ALOHA, DAMA with TDMA reservation access and DAMA with slotted ALOHA reservation access. The performance evaluation, based on detailed simulations with VSAT equipment and transaction traffic parameters, is summarized by curves of average delay and throughput vs. number of VSATs per channel for each of the protocols considered. Higher-order differences in delay performance are illustrated with appropriate delay distribution results and the sensitivity of performance with respect to key equipment and traffic parameters is investigated. For the transaction traffic model under consideration, the results suggest the use of SREJ-ALOHA among contention techniques or DAMA with slotted ALOHA reservation among controlled access alternatives. The trade-off between contention and reservation access is shown to be more complex, depending on the combination of average delay, peak delay, transmission cost and equipment complexity suited to the particular application. In Part II

1 To published in the next issue

of this paper on Ku-band VSAT networks, the issue of overall system design is considered.     

基于相控阵天线的“动中通”卫星通信终端研究

提出了一种新的“动中通”卫星终端的设计思路。主要从研究当前国内主流的“动中通”卫星通信终端着手,分析了在“动中通”卫星通信终端中采用相控阵技术的可行性,给出了一个典型的相控阵“动中通”卫星通信终端的实现框架,并进行了可工程实现的收发分离相控阵“动中通”卫星通信终端具体设计,提出设计关键点。     

21世纪全球卫星通信市场与业务发展趋势

从当前卫星通信市场的发展速度、主要特点和潜在的驱动力等几个方面对 2 1世纪的全球卫星通信市场做出预测 ,指出了一系列不同于传统卫星通信市场的特点 ,并重点分析了亚太地区卫星市场的发展趋势