Comparative economics of very high capacity communications satellites

Technology advances expected by the late 1980 or early 1990 time period will allow the construction of powerful and complex communications satellites with large multibeam antennas and very many transponders, and their operation and maintenance in geostationary orbit. The high sensitivity and effective radiated power of such satellites will enable the Earth stations using them to shrink dramatically in size and cost, thus becoming readily available to very large numbers of users as well as making possible new kinds and levels of communications services simply not possible with smaller satellites. This paper briefly describes three such new designs, concerning electronic mail transmission, educational TV distribution, and mass personal communications; it compares the users' service costs with those of terrestrial networks designed for the same performance.     

移动卫星通信捷联式天线稳定系统

介绍了一种应用激光陀螺惯性导航系统组成的移动卫星通信的捷联式天线稳定系统 ,给出了天线稳定和跟踪的控制方法和最优值搜索法。采用该系统可测量载体的姿态角和经度纬度 ,借助于惯性系统的输出信号控制天线轴使天线跟踪指定的卫星 ,卫星天线接收的信号可检测出跟踪误差 ,通过伺服系统控制天线转动 ,以使通讯信号为最强。采用了 GPS修正惯性系统的误差 ,成为 GPS/ INS的组合系统。在山区道路上跑车试验结果表明 ,当车的横滚角和俯仰角达到 6°,频率为 1Hz,方位角变化 180°时 ,在此动态条件下根据测量的卫星信号场强可知 ,跟踪误差小于 0 .2°。接收到的电视信号稳定清晰 ,图像和电话信号都是满意的。跑车试验表明 ,天线跟踪卫星的静态和动态精度完全满足了移动卫星通信的技术要求     

Economics of satellite communications systems

This paper is partly a tutorial, telling systematically how one goes about calculating the total annual costs of a satellite communications system, and partly the expression of some original ideas on the choice of parameters so as to minimize these costs.The calculation of costs can be divided into two broad categories. The first is technical and is concerned with estimating what particular equipment will cost and what will be the annual expense to maintain and operate it. One starts in the estimation of any new system by listing the principal items of equipment, such as satellites, earth stations of various sizes and functions, telemetry and tracking equipment and terrestrial interfaces, and then estimating how much each item will cost. Methods are presented for generating such estimates, based on a knowledge of the gross parameters, such as antenna size, coverage area, transmitter power and information rate. These parameters determine the system performance and it is usually possible, knowing them, to estimate the costs of the equipment rather well. Some formulae based on regression analyses are presented. Methods are then given for estimating closely related expenses, such as maintenance and operation, and then an approximate method is developed for estimating terrestrial interconnection costs.It is pointed out that in specific cases when tariff and geographical information are available, it is usually better to work with specific data, but nonetheless it is often desirable, especially in global system estimating, to approximate these interconnect costs without recourse to individual tariffs. The procedure results in a set of costs for the purchase of equipment and its maintenance, and a schedule of payments. Some payments will be incurred during the manufacture of the satellite and before any systems operation, but many will not be incurred until the system is no longer in use, e.g. incentives. In any case, with the methods presented in the first section, one arrives at a schedule of costs and payments for all the items and the years in which they will be incurred. The second category of costing problems is one of financing or engineering economics. All the costs are first “present valued” to some reference period using rates of return appropriate to the particular situation.One finally arrives at sets of annual costs which can be used as the basis for setting lease costs or revenue requirements and tariffs. The correspondence between methods using discounted rates of return and capital recovery formulae on one hand and those using various depreciation schedules, such as is typical of regulated industries on the other hand, is discussed.The remainder of the paper is devoted to discussing the relationship between critical parameters, such as replacement schedules, design lifetime, satellite power and Earth station antenna size, and the overall costs.It is shown that optima for these parameters may exist and can be calculated. In particular, the optimization of satellite replacement schedules to minimize the present value of total investment over a very long period is presented, along with simplified versions of the theory suitable for system planning.The choice of EIRP is also discussed and a procedure for choosing the value that minimizes the costs is shown.     

High thermally conductive communications equipment panel module for communications satellite

A new communications equipment panel module for satellite use has been developed to obtain a high thermal conductivity across the thickness in transversal direction of the panel. As the conventional communications equipment panel has a sandwich structure with aluminum alloy face sheets and a honeycomb core, the transversal thermal conductivity is relatively small mainly due to epoxy resin adhesive layers between the face sheet and the honeycomb core. Therefore, in order to dissipate high-heat flux towards space, a complicated thermal control system becomes necessary. The new panel module consists of a carbon-fiber-reinforced aluminum-alloy face sheet and a titanium-alloy core. A metallic bonding is used as the connection between the face sheet and core to enhance thermal conductivity of the panel is 1 × 10⁻¹ (W/K · mm) which is approx. 1000 times larger than that of the conventional panel.     

A Canadian system for satellite based advanced personal communications at the Ka-band

A Canadian Government program is currently under way to define, in detail, services and applications, user requirements, end-to-end system architecture and subsystem equipment design requirements for a demonstration on-board-processing (OBP) communications satellite system. The program has reached an advanced stage of definition. The prime directive of the overall mission is to provide demonstration and development of technology and services.

This paper begins by describing the development of our understanding of the true scope of advanced personal communications services and applications; the user expectations and hence terminal characteristics are also reviewed in the context of the competitive environment of other service offerings both existing and planned. In addition, the results of considerations on spacecraft complexity and hence feasibility, caused by the impact of each service option and the requirements for internetworking, are reviewed.     

Will fiber optics threaten satellite communications?

Since the first attempts of people to communicate over long distances the technology employed has not only become more complex in response to the amount of information that people have wanted to send but has, curiously enough, also exhibited cyclic tendencies in the course of the evolution to the present day. Now another change is occurring with the advent of ever-larger capacity fiber optic systems, and in some circles the thought is voiced ‘what of the future of satellite communications?’ This article addresses some of the issues at play in this environment and provides a perspective for consideration.     

Policy and regulatory risk considerations for satellite communications

The London Institute of Space Policy and Law is presenting a series of seminars on risks associated with space activity and its insurance, aimed at fostering better understanding of the risks particular to commercial space projects, and at encouraging appropriate policy measures. Seminar IV-I on 5 February 2010 focused on policy and regulatory risk considerations for satellite communications. After an introduction by the seminar chair Jeremy Rose, senior consultant at telecommunications consultancy Comsys, and a welcome from Institute Director Sa'id Mosteshar, four speakers outlined the ideal regulatory framework for satellite communications, as well as current regulatory and policy risks at the international, regional and national level. Risks were discussed in ITU, EU and UK procedures and policies and debate was continued from the floor. The event's rapporteur summarizes the issues highlighted by the speakers and some of the interventions from the floor.     

Laser satellite communications: current status and directions

This summary paper outlines the advantages of laser satellite communications (laser satcom) and summarizes the status of relevant programs. It concludes that laser satcom systems offer valuable performance capabilities and system advantages. It notes the urgent need for flight demonstrations to establish the viability and characterize the performance of laser satcom systems.     

Multi-cell satellite for the communications of year 2000

The multi-cell communication satellite concept allows an efficient use of the geostationary orbit and a large reduction of the bit transmission cost, as a Bell-type (phased array), multiple mobile narrow beams arrangement with SS-TDMA.It has a flat hexagonal flying-saucer shape, being erected in a low altitude orbit, through an automatic assembly process of a large number of quasi-identical hexagonal cells. Each cell has independent power supply, thrusters, RF modules etc….Total assembly requires 10 ARIANE V or 4 SHUTTLE launches. An automatic tooling assembly using simple iterative manoeuvers is used to obtain the final shape, from initial cylindrical packages.Transfer into geostationary orbit is provided by low-thrust bi-propellant units attached to the cells, and released after burn-out. Assembly and transfer duration is about 6 months.Total traffic to 1000–2000 towns being 100 Gbits/s, the expected reduction of bit-transmission cost relative to year 1981 is 75–100 fold.     

Trends in the design of future communications satellite systems

This paper presents a review of the trends in communication satellite technology. In the near term the development of moderate size, dedicated satellites is to be expected. In the long term international coordination of orbit and spectrum allocations, introduction of higher-frequency bands, spectrum conserving techniques and the concept of large communication platforms deserve particular attention. Means to improve the cost effectiveness of satellite communications system and technology aspects are considered. Finally some German contributions to these developments are presented, mainly concerning high-power TWTs in the 12 and 20 GHz range.     

Developing the next phase in NASAs satellite communications program

NASAs early efforts in satellite communications development brought confidence in space technology use for improved telecommunications. New, worldwide satellite communications systems have resulted, and are now on a commercial, self-sustaining operational basis. Since 1973, NASA has conducted hundreds of user experiments and demonstrated newer technology using ATS-1, -3, -6 and CTS. Now, projections show that the commercial demand will continue to increase, soon exceeding the current technology's capacity.As a result, U.S. Space Policy affirmed in 1978 that NASA should embark again on a research and development program for satellite communications with specific, characterized goals. The resulting plan's elements include $\text{30}\text{20}\text{GHz}$ Ka-band technology, extending the current work in advanced multi-beam antennas; a narrowband system and technology study that could lead to mobile and transportable communications developments; and studies of future uses of technology in communications. The program plan and its evolution are described, followed by a report of current progress and future expectations.     

The USSR and satellite communications : Competition and cooperation

This article examines the USSR's satellite communications provision in the international arena. The author first outlines the Intercosmos programme, collaboration between the USSR and France and India, and maritime satellite communications. He then discusses in detail the INTERSPUTNIK system, and Soviet international coverage and competitiveness in television. In conclusion, the complex interaction and overlap between cooperation and competition in space is explained.     

Experiments on the quick-relief medical communications via the Japan's domestic communication satellite CS-2 for the case of disasters and emergencies.

Experiments on the quick-relief medical communications via the CS-2 satellite were carried out by using two types of 30/20 GHz small transportable earth stations whose antenna diameters are 1 and 2 m. As the terminal equipments, FM-SCPC systems with a one-telephone-equivalent channel were prepared for the transmission of voice, color freezed picture (9.6 kbps), supersonic echo signal and heart sound from a electrocardiograph. Signals from various medical equipments were transmitted by an FM-SCPC system from Simizu harbour (1 m station) to Tokyo transportable station (2 m), assuming that a person was injured in the ship and the ship came alongside the pier. Transmitted materials are mainly various kinds of pictures of affected parts, X-ray films and electrocardiograph with breathing sounds. It was found possible to send various medical information mentioned above via CS-2 by the 30/20 GHz simple communication systems with one-telephone-equivalent channel. Doctors suggested it would be possible to judge very well about the patients' emergency conditions and to give quick consult with inevitable treatment procedures for them. However, a few problems were found in the Hi-Fi reproduction of original colors and in the transmission of heart sounds in the very low frequency band less than 300 Hz.     

新一代高通量卫星通信系统载荷关键技术研究

随着商业竞争的不断加剧,更大容量以及更高灵活性成为了高通量(high throughput satellite,HTS)系统发展的主要目标,新一代的HTS系统即将进入到"Tbps"时代.在介绍HTS系统基本概念及组成的基础上,对HTS系统的发展历程进行了简要总结,按照能力和发展时期,HTS卫星的发展历程大致可划分为四代.重点结合新一代HTS系统的发展,从卫星载荷角度分析了高通量卫星载荷的关键技术,主要包括能够大幅提升系统通信容量的超大规模高性能多波束天线技术,能够提高组网及业务应用灵活性的跳波束通信技术、灵活载荷技术、数字透明转发处理技术以及能够优化系统和载荷设计的波束预编码技术和基于微波光子的星上转发技术等,旨在为我国新一代HTS系统的建设发展提供参考.     

Research and development of On-Board Processor for advanced mobile satellite communications

This paper describes the research and development of an On-Board Processor (OBP) for a mobile satellite communications system using a geostationaly satellite. The system, which based on Multi-Carrier Time Division Multiple Access, can realize high performance and facilitate the use of miniature hand-held mobile Earth terminals.

Our research and development results indicate as follows.

1. 1) The simultaneous-slot switching method will be the most suitable for an on-board base-band switching with consideration of traffic capacity, time delay, and hardware scale.

2. 2) The OBP performs channel exchange with regeneration that contributes to a reduction in the size of mobile terminals because of the coding gain.

3. 3) Many kinds of Application Specific Integrated Circuits are designed to realize large channel capacity and reduce the size and power consumption of the OBP. These OBP design can increase the channel capacity, which is equivalent to in 5.6kbps voice channel, up to over 500 channels within 5MHz frequency band

Some results are applied to the OBP being developed for the Japanese Engineering Test Satellite VII (ETS-VB).     

Economic effect of satellite communications based on the Great East Japan Earthquake

On 11 March 2011, an undersea earthquake of magnitude 9.0, the largest ever recorded in Japan, occurred off the Oshika Peninsula on the Pacific coast of the Tohoku region. The hypocentral region extended for 500 km in the north–south direction from Iwate Prefecture to Ibaraki Prefecture, and for 200 km in east–west direction. The earthquake generated a tsunami with a height of more than 10 m and a run-up height of up to 40.0 m in certain places, which inflicted devastating damage on the coastal areas of the Tohoku and Kanto regions. In addition to the tsunami, the earthquake caused shaking, liquefaction, subsidence, and the collapse of dams, causing major damage to vast areas in the Tohoku and Kanto regions and disrupting various types of infrastructure, including communication. In light of this unprecedented damage, satellite communications were important from various perspectives while terrestrial communications systems were damaged, and an objective evaluation of the role played by satellite communications is relevant to its future installation, adoption and use as a standalone or backup system. Furthermore, satellite communications can help reduce the extent of damage, particularly damage to communications systems, inflicted by strong earthquakes in the future. Accordingly, we report a preliminary quantitative evaluation of the role of satellite communications in the Great East Japan Earthquake, of the role of satellite communications if it becomes widespread, and of its expected role in future large-scale earthquakes in terms of the economic effect converted into cost.     

基于高轨导航接收机的自动化地面测试系统

高轨卫星导航接收机是实现高轨航天器自主定轨的核心设备。为在地面测试阶段对高轨卫星导航接收机进行充分高效的验证,亟需设计基于高轨卫星导航接收机的地面测试系统。设计了一种基于高轨卫星导航接收机的自动化地面测试系统,主要创新点如下：第一,本系统可对高轨卫星导航接收机实际在轨状态下接收到的导航星座信号进行仿真;第二,具有模拟包含北斗三号等多导航卫星星座信号的功能;第三,本系统充分考虑自动化、通用化与一体化设计。提出的基于高轨卫星导航接收机的自动化地面测试系统能够在地面测试阶段对高轨卫星导航接收机进行充分验证,并充分考虑测试实施,从自动化、通用化、一体化方面提升测试效率,减少人为操作失误导致的质量问题,解决人工判读带来的误判漏判问题。     

Tether satellite system collision study

A study was performed to determine the probability of collision with resident space objects and untrackable debris for the tether component of the Tethered Satellite System (TSS) after it broke away from the space shuttle orbiter (mission STS-75) in February 1996. Both an analytical and a numerical approach were used in this study, and the results obtained with these two methods were found to be in good agreement. These results show that the deployed tether is expected to have been impacted by several particles 0.1 mm or larger in size. The probability of collision with objects 10 cm in size or larger was on the order of 10⁻³ per month. Since the severed tether reentered within one month after deployment, the collision hazard to other objects while in orbit was small. The analytical methods used in this study are general and can be applied to future tether collision evaluations.