Mobile satellite service communications tests using a NASA satellite

Science.gov (United States)

Chambers, Katherine H.; Koschmeder, Louis A.; Hollansworth, James E.; ONeill, Jack; Jones, Robert E.; Gibbons, Richard C.

1995-01-01

Emerging applications of commercial mobile satellite communications include satellite delivery of compact disc (CD) quality radio to car drivers who can select their favorite programming as they drive any distance; transmission of current air traffic data to aircraft; and handheld communication of data and images from any remote corner of the world. Experiments with the enabling technologies and tests and demonstrations of these concepts are being conducted before the first satellite is launched by utilizing an existing NASA spacecraft.

Soviet satellite communications science and technology

Energy Technology Data Exchange (ETDEWEB)

Birch, J.N.; Campanella, S.J.; Gordon, G.D.; McElroy, D.R.; Pritchard, W.L.; Stamminger, R.

1991-08-01

This is a report by six US scientists and engineers concerning the current state of the art and projections of future Soviet satellite communications technologies. The panel members are experts in satellite stabilization, spacecraft environments, space power generation, launch systems, spacecraft communications sciences and technologies, onboard processing, ground stations, and other technologies that impact communications. The panel assessed the Soviet ability to support high-data-rate space missions at 128 Mbps by evaluating current and projected Soviet satellite communications technologies. A variety of space missions were considered, including Earth-to-Earth communications via satellites in geostationary or highly elliptical orbits, those missions that require space-to-Earth communications via a direct path and those missions that require space-to-Earth communications via a relay satellite. Soviet satellite communications capability, in most cases, is 10 years behind that of the United States and other industrialized nations. However, based upon an analysis of communications links needed to support these missions using current Soviet capabilities, it is well within the current Soviet technology to support certain space missions outlined above at rates of 128 Mbps or higher, although published literature clearly shows that the Soviet Union has not exceeded 60 Mbps in its current space system. These analyses are necessary but not sufficient to determine mission data rates, and other technologies such as onboard processing and storage could limit the mission data rate well below that which could actually be supported via the communications links. Presently, the Soviet Union appears to be content with data rates in the low-Earth-orbit relay via geostationary mode of 12 Mbps. This limit is a direct result of power amplifier limits, spacecraft antenna size, and the utilization of K{sub u}-band frequencies. 91 refs., 16 figs., 15 tabs.

Ground test of satellite constellation based quantum communication

OpenAIRE

Liao, Sheng-Kai; Yong, Hai-Lin; Liu, Chang; Shentu, Guo-Liang; Li, Dong-Dong; Lin, Jin; Dai, Hui; Zhao, Shuang-Qiang; Li, Bo; Guan, Jian-Yu; Chen, Wei; Gong, Yun-Hong; Li, Yang; Lin, Ze-Hong; Pan, Ge-Sheng

2016-01-01

Satellite based quantum communication has been proven as a feasible way to achieve global scale quantum communication network. Very recently, a low-Earth-orbit (LEO) satellite has been launched for this purpose. However, with a single satellite, it takes an inefficient 3-day period to provide the worldwide connectivity. On the other hand, similar to how the Iridium system functions in classic communication, satellite constellation (SC) composed of many quantum satellites, could provide global...

Protected transitional solution to transformational satellite communications

Science.gov (United States)

Brand, Jerry C.

2005-06-01

As the Warfighter progresses into the next generation battlefield, transformational communications become evident as an enabling technology. Satellite communications become even more vital as the battles range over greater non-contiguous spaces. While current satellite communications provide suitable beyond line-of-sight communications and the Transformational Communications Architecture (TCA) sets the stage for sound information exchange, a realizable transition must occur to ensure successful succession to this higher level. This paper addresses the need for a planned escalation to the next generation satellite communications architecture and offers near-term alternatives. Commercial satellite systems continue to enable the Warfighter to reach back to needed information resources, providing a large majority of available bandwidth. Four areas of concentration for transition include encrypted Telemetry, Tracking and Control (or Command) (TT&C), encrypted and covered data, satellite attack detection and protection, and operational mobility. Solution methodologies include directly embedding COMSEC devices in the satellites and terminals, and supplementing existing terminals with suitable equipment and software. Future satellites planned for near-term launches can be adapted to include commercial grade and higher-level secure equipment. Alternately, the expected use of programmable modems (Software Defined Radios (SDR)) enables incorporation of powerful cipher methods approaching military standards as well as waveforms suitable for on-the-move operation. Minimal equipment and software additions on the satellites can provide reasonable attack detection and protection methods in concert with the planned satellite usage. Network management suite modifications enable cohesive incorporation of these protection schemes. Such transitional ideas offer a smooth and planned transition as the TCA takes life.

Satellite Communication and Long Distance Education

OpenAIRE

Hafied Cangara

2016-01-01

Since Indonesia introduced communication satellite for telecommunication network, the satellite has brought a number of advantages for national development in various areas, such as telephone network, mass media development, business, education, politics, security and national defence as well as regional and International cooperation. In education, satellite communication could be used for long-distance learning as implemented by 13 state universities in eastern parts of Indonesia. It is also...

ESA's satellite communications programme

Science.gov (United States)

Bartholome, P.

1985-02-01

The developmental history, current status, and future plans of the ESA satellite-communications programs are discussed in a general survey and illustrated with network diagrams and maps. Consideration is given to the parallel development of national and European direct-broadcast systems and telecommunications networks, the position of the European space and electronics industries in the growing world market, the impact of technological improvements (both in satellite systems and in ground-based networks), and the technological and commercial advantages of integrated space-terrestrial networks. The needs for a European definition of the precise national and international roles of satellite communications, for maximum speed in implementing such decisions (before the technology becomes obsolete), and for increased cooperation and standardization to assure European equipment manufacturers a reasonable share of the market are stressed.

Domestic Communication Satellites

Science.gov (United States)

Horowitz, Andrew

1974-01-01

A discussion of the Federal Communications Commission's new policy on domestic satellites in light of our 1) military and economic history; 2) corporate interests; 3) citizen surveillance; and 4) media control. (HB)

Clock Management Data Analysis for Satellite Communications

National Research Council Canada - National Science Library

Gross, Rachel; Melkers, Raimond

2005-01-01

The U.S. Naval Research Laboratory has installed GPS-based timing systems in several Defense Satellite Communication System "DSCS-III" satellite communication facilities to support the Single Channel Transponder "SCT" program...

Satellite Communications Using Commercial Protocols

Science.gov (United States)

Ivancic, William D.; Griner, James H.; Dimond, Robert; Frantz, Brian D.; Kachmar, Brian; Shell, Dan

2000-01-01

NASA Glenn Research Center has been working with industry, academia, and other government agencies in assessing commercial communications protocols for satellite and space-based applications. In addition, NASA Glenn has been developing and advocating new satellite-friendly modifications to existing communications protocol standards. This paper summarizes recent research into the applicability of various commercial standard protocols for use over satellite and space- based communications networks as well as expectations for future protocol development. It serves as a reference point from which the detailed work can be readily accessed. Areas that will be addressed include asynchronous-transfer-mode quality of service; completed and ongoing work of the Internet Engineering Task Force; data-link-layer protocol development for unidirectional link routing; and protocols for aeronautical applications, including mobile Internet protocol routing for wireless/mobile hosts and the aeronautical telecommunications network protocol.

Advanced mobile satellite communications using COMETS satellite in MM-wave and Ka-band

Science.gov (United States)

Ohmori, Shingo; Isobe, Shunkichi; Takeuchi, Makoto; Naito, Hideyuki

1993-01-01

Early in the 21st century, the demand for personal communications using mobile, hand-held, and VSAT terminals will rapidly increase. In a future system, many different types of services should be provided with one-hop connection. The Communications Research Laboratory (CRL) has studied a future advanced mobile satellite communications system using millimeter wave and Ka band. In 1990, CRL started the Communications and Broadcasting Engineering Test Satellite (COMETS) project. The satellite has been developed in conjunction with NASDA and will be launched in 1997. This paper describes the COMETS payload configuration and the experimental system for the advanced mobile communications mission.

Satellite Communication and Long Distance Education

Directory of Open Access Journals (Sweden)

Hafied Cangara

2016-02-01

Full Text Available Since Indonesia introduced communication satellite for telecommunication network, the satellite has brought a number of advantages for national development in various areas, such as telephone network, mass media development, business, education, politics, security and national defence as well as regional and international cooperation. In education, satellite communication could be used for long-distance learning as implemented by 13 state universities in eastern parts of Indonesia. It is also possible to develop the Open University System in teaching and learning process, particularly since the internet technology has been intensively used

Recent Korean R&D in Satellite Communications

Science.gov (United States)

Lee, Ho-Jin; Kim, Jae Moung; Lee, Byung-Seub; Lee, Han; Ryoo, Jang-Soo

The R&D in satellite communications in Korea has been driven mainly by KCC (Korea Communications Commission) but in a small scale compared to Korea space development program organized by MEST (Ministry of Education, Science and Technology). Public and civilian satcom sector R&D has been led mainly by ETRI with small/medium companies contrary to rare investment in private sector while military sector R&D has been orchestrated by ADD with defense industry. By the COMS (Communication, Ocean and Meteorological Satellite) experimental Ka-band payload, Korea pursues a space qualification of own technology for national infrastructure evolution as well as industrialization of space R&D results. Once COMS launched and space qualified in 2009, subsequent application experiments and new technology R&D like UHDTV will entail service and industry promotion. The payload technology is expected for the next Korean commercial satellites or for new OBP satellites. The COMS ground control system and GNSS ground station technologies are under development for COMS operation and enhanced GNSS services along with advent of Galileo respectively. Satellite broadband mobile VSAT based on DVB-S2/RCS (+M) and low profile tracking antennas have been developed for trains, ships, and planes. While APSI is developing GMR-1 based Thuraya handset functions, ETRI is designing IMT-Advanced satellite radio interface for satellite and terrestrial dual-mode handheld communication system like Japanese STICS, with universities' satellite OFDM researches. A 21GHz Ka-band higher-availability scalable HD broadcasting technology and SkyLife's hybrid satellite IPTV technology are being developed. In near term Korea will extend R&D programs to upgrade the space communication infrastructure for universal access to digital opportunity and safer daily life from disaster, and to promote space green IT industrialization, national security, and space resources sovereign. Japanese stakeholders are invited to establish

Cockpit weather graphics using mobile satellite communications

Science.gov (United States)

Seth, Shashi

1993-01-01

Many new companies are pushing state-of-the-art technology to bring a revolution in the cockpits of General Aviation (GA) aircraft. The vision, according to Dr. Bruce Holmes - the Assistant Director for Aeronautics at National Aeronautics and Space Administration's (NASA) Langley Research Center, is to provide such an advanced flight control system that the motor and cognitive skills you use to drive a car would be very similar to the ones you would use to fly an airplane. We at ViGYAN, Inc., are currently developing a system called the Pilot Weather Advisor (PWxA), which would be a part of such an advanced technology flight management system. The PWxA provides graphical depictions of weather information in the cockpit of aircraft in near real-time, through the use of broadcast satellite communications. The purpose of this system is to improve the safety and utility of GA aircraft operations. Considerable effort is being extended for research in the design of graphical weather systems, notably the works of Scanlon and Dash. The concept of providing pilots with graphical depictions of weather conditions, overlaid on geographical and navigational maps, is extremely powerful.

Estimating Rain Attenuation In Satellite Communication Links

Science.gov (United States)

Manning, R. M.

1991-01-01

Attenuation computed with help of statistical model and meteorological data. NASA Lewis Research Center Satellite Link Attenuation Model (SLAM) program QuickBASIC computer program evaluating static and dynamic statistical assessment of impact of rain attenuation on communication link established between Earth terminal and geosynchronous satellite. Application in specification, design, and assessment of satellite communication links for any terminal location in continental United States. Written in Microsoft QuickBASIC.

Digital, Satellite-Based Aeronautical Communication

Science.gov (United States)

Davarian, F.

1989-01-01

Satellite system relays communication between aircraft and stations on ground. System offers better coverage with direct communication between air and ground, costs less and makes possible new communication services. Carries both voice and data. Because many data exchanged between aircraft and ground contain safety-related information, probability of bit errors essential.

A New Era Begins: Satellite Communications and Development.

Science.gov (United States)

Pelton, Joseph N.

This overview of changes in the field of telecommunications development produced by satellite communications over the last 15 years focuses on applications of satellite systems for educational and health purposes in developing countries. Satellite communications development from 1974 to 1986 is identified as the first stage of telecommunications…

Anti-jamming Technology in Small Satellite Communication

Science.gov (United States)

Jia, Zixiang

2018-01-01

Small satellite communication has an increasingly important position among the wireless communications due to the advantages of low cost and high technology. However, in view of the case that its relay station stays outside the earth, its uplink may face interference from malicious signal frequently. Here this paper classified enumerates existing interferences, and proposes channel signals as main interference by comparison. Based on a basic digital communication process, then this paper discusses the possible anti - jamming techniques that commonly be realized at all stages in diverse processes, and comes to the conclusion that regarding the spread spectrum technology and antenna anti-jamming technology as fundamental direction of future development. This work provides possible thought for the design of new small satellite communication system with the coexistence of multi - technologies. This basic popular science can be consulted for people interested in small satellite communication.

Technical comparison of several global mobile satellite communications systems

Science.gov (United States)

Comparetto, Gary M.

The era of satellite-based mobile satellite communications (MSC) systems started with the first MARISAT satellite which was launched into a geostationary orbit over the Pacific Ocean in 1976 to provide communications between ships and shore stations. The combination of high cost and unacceptably large equipment has kept the space-based MSC systems from appealing to the wider market of personal mobile communications. The progress made over the last ten years, however, in digital voice processing, satellite technology, and component miniaturization has resulted in the viability of satellite-based mobile satellite communications systems to meet the growing market in personal mobile communications using handsets similar to those currently in use with land-based cellular systems. Three of the more mature LEO/MEO satellite systems are addressed in this paper including GLOBALSTAR, Iridium, and Odyssey. The system architectures of each system are presented along with a description of the satellite and user handset designs and the multiaccess techniques employed. It will be shown that, although a number of similarities exist among the system addressed, each system is unique in a variety of significant design areas. It is concluded that the technical feasibility of satellite-based mobile satellite communications systems seems to be secure. It will be challenging, however, for the vendors to actually develop and deploy these systems in a cost effective, timely, and reliable way that meets a continually evolving set of requirements based upon a rapidly changing technology base.

The Information Revolution.

Science.gov (United States)

Gilder, George

1993-01-01

A technological revolution is erupting all about us. A millionfold rise in computation and communications cost effectiveness will transform all industries and bureaucracies. The information revolution is a decentralizing, microcosmic electronic force opposing the centralizing, controlling Industrial-Age mentality persisting in schools. Television…

Odyssey, an optimized personal communications satellite system

Science.gov (United States)

Rusch, Roger J.

Personal communications places severe demands on service providers and transmission facilities. Customers are not satisfied with the current levels of service and want improvements. Among the characteristics that users seek are: lower service rates, hand held convenience, acceptable time delays, ubiquitous service, high availability, reliability, and high quality. The space industry is developing commercial space systems for providing mobile communications to personal telephones. Provision of land mobile satellite service is fundamentally different from the fixed satellite service provided by geostationary satellites. In fixed service, the earth based antennas can depend on a clear path from user to satellite. Mobile users in a terrestrial environment commonly encounter blockage due to vegetation, terrain or buildings. Consequently, high elevation angles are of premium value. TRW studied the issues and concluded that a Medium Earth Orbit constellation is the best solution for Personal Communications Satellite Service. TRW has developed Odyssey, which uses twelve satellites in medium altitude orbit to provide personal communications satellite service. The Odyssey communications system projects a multibeam antenna pattern to the Earth. The attitude control system orients the satellites to ensure constant coverage of land mass and coastal areas. Pointing can be reprogrammed by ground control to ensure optimized coverage of the desired service areas. The payload architecture features non-processing, "bent pipe" transponders and matrix amplifiers to ensure dynamic power delivery to high demand areas. Circuit capacity is 3000 circuits per satellite. Each satellite weighs 1917 kg (4226 pounds) at launch and the solar arrays provide 3126 Watts of power. Satellites are launched in pairs on Ariane, Atlas, or other vehicles. Each satellite is placed in a circular orbit at an altitude of 10,354 km. There are three orbit planes inclined at 55° to the equatorial plane

Research of the key technology in satellite communication networks

Science.gov (United States)

Zeng, Yuan

2018-02-01

According to the prediction, in the next 10 years the wireless data traffic will be increased by 500-1000 times. Not only the wireless data traffic will be increased exponentially, and the demand for diversified traffic will be increased. Higher requirements for future mobile wireless communication system had brought huge market space for satellite communication system. At the same time, the space information networks had been greatly developed with the depth of human exploration of space activities, the development of space application, the expansion of military and civilian application. The core of spatial information networks is the satellite communication. The dissertation presented the communication system architecture, the communication protocol, the routing strategy, switch scheduling algorithm and the handoff strategy based on the satellite communication system. We built the simulation platform of the LEO satellites networks and simulated the key technology using OPNET.

Satellite communications network design and analysis

CERN Document Server

Jo, Kenneth Y

2011-01-01

This authoritative book provides a thorough understanding of the fundamental concepts of satellite communications (SATCOM) network design and performance assessments. You find discussions on a wide class of SATCOM networks using satellites as core components, as well as coverage key applications in the field. This in-depth resource presents a broad range of critical topics, from geosynchronous Earth orbiting (GEO) satellites and direct broadcast satellite systems, to low Earth orbiting (LEO) satellites, radio standards and protocols.This invaluable reference explains the many specific uses of

Satellite communication from user to user

Science.gov (United States)

Gern, Manfred

Satellite communication systems which allow a multitude of user-to-user, point-to-point, and multipoint connections, are presented. The bit rates are 64 kbit/sec and multiples, up to 1.92 Mbit/sec. If required, the ground-stations are installed at the customer's site or at suitable locations in order to serve several customers. However, technical requirements for station location have also to be fulfulled, in order to avoid interference with terrestrial radio services. The increasing number of participants to Satellite Multi Service and INTELSAT Business Services imposes the solution of the problem of communication using cheap techniques. The changes of the German Federal Post Office also permit the economic use of satellite radio techniques for short distances.

A Hybrid Satellite-Terrestrial Approach to Aeronautical Communication Networks

Science.gov (United States)

Kerczewski, Robert J.; Chomos, Gerald J.; Griner, James H.; Mainger, Steven W.; Martzaklis, Konstantinos S.; Kachmar, Brian A.

2000-01-01

Rapid growth in air travel has been projected to continue for the foreseeable future. To maintain a safe and efficient national and global aviation system, significant advances in communications systems supporting aviation are required. Satellites will increasingly play a critical role in the aeronautical communications network. At the same time, current ground-based communications links, primarily very high frequency (VHF), will continue to be employed due to cost advantages and legacy issues. Hence a hybrid satellite-terrestrial network, or group of networks, will emerge. The increased complexity of future aeronautical communications networks dictates that system-level modeling be employed to obtain an optimal system fulfilling a majority of user needs. The NASA Glenn Research Center is investigating the current and potential future state of aeronautical communications, and is developing a simulation and modeling program to research future communications architectures for national and global aeronautical needs. This paper describes the primary requirements, the current infrastructure, and emerging trends of aeronautical communications, including a growing role for satellite communications. The need for a hybrid communications system architecture approach including both satellite and ground-based communications links is explained. Future aeronautical communication network topologies and key issues in simulation and modeling of future aeronautical communications systems are described.

Communication Satellite: Nigeria's Efforts at Bridging Digital Divide ...

African Journals Online (AJOL)

Communication Satellite in the wireless age has the potentials of bridging the digital gulf that exists between civilized and developing nation. If well used, communication Satellite is a potent infrastructure of addressing technology convergence for holistic national development. This paper examines Nigeria's technological ...

Potential markets for advanced satellite communications

Science.gov (United States)

Adamson, Steven; Roberts, David; Schubert, Leroy; Smith, Brian; Sogegian, Robert; Walters, Daniel

1993-09-01

This report identifies trends in the volume and type of traffic offered to the U.S. domestic communications infrastructure and extrapolates these trends through the year 2011. To describe how telecommunications service providers are adapting to the identified trends, this report assesses the status, plans, and capacity of the domestic communications infrastructure. Cable, satellite, and radio components of the infrastructure are examined separately. The report also assesses the following major applications making use of the infrastructure: (1) Broadband services, including Broadband Integrated Services Digital Network (BISDN), Switched Multimegabit Data Service (SMDS), and frame relay; (2) mobile services, including voice, location, and paging; (3) Very Small Aperture Terminals (VSAT), including mesh VSAT; and (4) Direct Broadcast Satellite (DBS) for audio and video. The report associates satellite implementation of specific applications with market segments appropriate to their features and capabilities. The volume and dollar value of these market segments are estimated. For the satellite applications able to address the needs of significant market segments, the report also examines the potential of each satellite-based application to capture business from alternative technologies.

Potential markets for advanced satellite communications

Science.gov (United States)

Adamson, Steven; Roberts, David; Schubert, Leroy; Smith, Brian; Sogegian, Robert; Walters, Daniel

1993-01-01

This report identifies trends in the volume and type of traffic offered to the U.S. domestic communications infrastructure and extrapolates these trends through the year 2011. To describe how telecommunications service providers are adapting to the identified trends, this report assesses the status, plans, and capacity of the domestic communications infrastructure. Cable, satellite, and radio components of the infrastructure are examined separately. The report also assesses the following major applications making use of the infrastructure: (1) Broadband services, including Broadband Integrated Services Digital Network (BISDN), Switched Multimegabit Data Service (SMDS), and frame relay; (2) mobile services, including voice, location, and paging; (3) Very Small Aperture Terminals (VSAT), including mesh VSAT; and (4) Direct Broadcast Satellite (DBS) for audio and video. The report associates satellite implementation of specific applications with market segments appropriate to their features and capabilities. The volume and dollar value of these market segments are estimated. For the satellite applications able to address the needs of significant market segments, the report also examines the potential of each satellite-based application to capture business from alternative technologies.

Use of Advanced Solar Cells for Commercial Communication Satellites

Science.gov (United States)

Bailey, Sheila G.; Landis, Geoffrey A.

1995-01-01

The current generation of communications satellites are located primarily in geosynchronous Earth orbit (GEO). Over the next decade, however, a new generation of communications satellites will be built and launched, designed to provide a world-wide interconnection of portable telephones. For this mission, the satellites must be positioned in lower polar and near-polar orbits. To provide complete coverage, large numbers of satellites will be required. Because the required number of satellites decreases as the orbital altitude is increased, fewer satellites would be required if the orbit chosen were raised from low to intermediate orbit. However, in intermediate orbits, satellites encounter significant radiation due to trapped electrons and protons. Radiation tolerant solar cells may be necessary to make such satellites feasible. We analyze the amount of radiation encountered in low and intermediate polar orbits at altitudes of interest to next-generation communication satellites, calculate the expected degradation for silicon, GaAs, and InP solar cells, and show that the lifetimes can be significantly increased by use of advanced solar cells.

Satellite Communication and Development: A Reassessment.

Science.gov (United States)

Hudson, Heather E.

The potential benefits of satellite communications development have been recognized since the notion of a geostationary "space platform" was proposed by Arthur C. Clarke in 1945. Although there have been examples of developmental applications of satellite technology, the promise has been slow in being fulfilled. The history of the…

Network design consideration of a satellite-based mobile communications system

Science.gov (United States)

Yan, T.-Y.

1986-01-01

Technical considerations for the Mobile Satellite Experiment (MSAT-X), the ground segment testbed for the low-cost spectral efficient satellite-based mobile communications technologies being developed for the 1990's, are discussed. The Network Management Center contains a flexible resource sharing algorithm, the Demand Assigned Multiple Access scheme, which partitions the satellite transponder bandwidth among voice, data, and request channels. Satellite use of multiple UHF beams permits frequency reuse. The backhaul communications and the Telemetry, Tracking and Control traffic are provided through a single full-coverage SHF beam. Mobile Terminals communicate with the satellite using UHF. All communications including SHF-SHF between Base Stations and/or Gateways, are routed through the satellite. Because MSAT-X is an experimental network, higher level network protocols (which are service-specific) will be developed only to test the operation of the lowest three levels, the physical, data link, and network layers.

DS-CDMA satellite diversity reception for personal satellite communication: Downlink performance analysis

Science.gov (United States)

DeGaudenzi, Riccardo; Giannetti, Filippo

1995-01-01

The downlink of a satellite-mobile personal communication system employing power-controlled Direct Sequence Code Division Multiple Access (DS-CDMA) and exploiting satellite-diversity is analyzed and its performance compared with a more traditional communication system utilizing single satellite reception. The analytical model developed has been thoroughly validated by means of extensive Monte Carlo computer simulations. It is shown how the capacity gain provided by diversity reception shrinks considerably in the presence of increasing traffic or in the case of light shadowing conditions. Moreover, the quantitative results tend to indicate that to combat system capacity reduction due to intra-system interference, no more than two satellites shall be active over the same region. To achieve higher system capacity, differently from terrestrial cellular systems, Multi-User Detection (MUD) techniques are likely to be required in the mobile user terminal, thus considerably increasing its complexity.

Implementation of Multiple Access Techniques Applicable for Maritime Satellite Communications

OpenAIRE

Stojce Dimov Ilcev

2013-01-01

In this paper are introduced fundamentals, characteristics, advantages and disadvantages of Multiple Access (MA) employed as transmission techniques in the Maritime Mobile Satellite Communications (MMSC) between ships and Coast Earth Station (CES) via Geostationary Earth Orbit (GEO) or Not-GEO satellite constellations. In fixed satellite communication, as a rule, especially in MMSC many users are active at the same time. The problem of simultaneous communications between many single or multip...

A Survey of Satellite Communications System Vulnerabilities

National Research Council Canada - National Science Library

Steinberger, Jessica A

2008-01-01

The U.S. military's increasing reliance on commercial and military communications satellites to enable widely-dispersed, mobile forces to communicate makes these space assets increasingly vulnerable to attack by adversaries...

Application of Vision Metrology to In-Orbit Measurement of Large Reflector Onboard Communication Satellite for Next Generation Mobile Satellite Communication

Science.gov (United States)

Akioka, M.; Orikasa, T.; Satoh, M.; Miura, A.; Tsuji, H.; Toyoshima, M.; Fujino, Y.

2016-06-01

Satellite for next generation mobile satellite communication service with small personal terminal requires onboard antenna with very large aperture reflector larger than twenty meters diameter because small personal terminal with lower power consumption in ground base requires the large onboard reflector with high antenna gain. But, large deployable antenna will deform in orbit because the antenna is not a solid dish but the flexible structure with fine cable and mesh supported by truss. Deformation of reflector shape deteriorate the antenna performance and quality and stability of communication service. However, in case of digital beam forming antenna with phased array can modify the antenna beam performance due to adjustment of excitation amplitude and excitation phase. If we can measure the reflector shape precisely in orbit, beam pattern and antenna performance can be compensated with the updated excitation amplitude and excitation phase parameters optimized for the reflector shape measured every moment. Softbank Corporation and National Institute of Information and Communications Technology has started the project "R&D on dynamic beam control technique for next generation mobile communication satellite" as a contracted research project sponsored by Ministry of Internal Affairs and Communication of Japan. In this topic, one of the problem in vision metrology application is a strong constraints on geometry for camera arrangement on satellite bus with very limited space. On satellite in orbit, we cannot take many images from many different directions as ordinary vision metrology measurement and the available area for camera positioning is quite limited. Feasibility of vision metrology application and general methodology to apply to future mobile satellite communication satellite is to be found. Our approach is as follows: 1) Development of prototyping simulator to evaluate the expected precision for network design in zero order and first order 2) Trial

Advanced mobile satellite communications system using Ka and MM-wave bands in Japan's R and D satellite project

Science.gov (United States)

Isobe, Shunkichi; Ohmori, Shingo; Hamamoto, Naokazu; Yamamoto, Minoru

1991-01-01

Communications Research Laboratory (CRL) studied an advanced mobile satellite communications system using Ka and millimeter-wave bands in the R&D Satellite project. The project started in 1990 and the satellite will be launched in 1997. On-board multi-beam interconnecting is one of basic functions to realize one-hop connection among Very Small Aperture Terminals (VSATs), mobile, and hand-held terminals in future mobile satellite communications system. An Intermediate Frequency (IF) filter bank and regenerative transponder are suitable for this function. The transponder configuration of an advanced mobile communications mission of the R&D Satellite for experiment is shown. High power transmitters of Ka and millimeter-wave bands, a 3x3 IF filter band and Single Channel Per Carrier/Time Division Multiplexing (SCPC/TDM) regenerative MODEMS, which will be boarded on the R&D Satellite, are being developed for the purpose of studying the feasibility of advanced mobile communications system.

SDR Implementation for Satellite Communication

OpenAIRE

Jakobsson, Carin; Sjödin, Olof

2017-01-01

SDR (Software Defined Radio) is a radio communicationsystem that has been of great interest and developmentover the last 20 years. It decreases communication costs significantlyas it replaces expensive analogue system components withcheap and flexible digital ones. In this article we describe anSDR implementation for communication with the SEAM (SmallExplorer for Advances Missions) satellite, a CubeSat satellitethat will perform high quality magnetic measurements in theEarth orbit. The projec...

Communication satellites to enter a new age of flexibility

Science.gov (United States)

Balty, Cédric; Gayrard, Jean-Didier; Agnieray, Patrick

2009-07-01

To cope with the economical and technical evolutions of the communication market and to better compete with or complement terrestrial networks, satellite operators are requiring more flexible satellites. It allows a better fleet planning potential and back-up policy, a more standardized and efficient procurement process, mission adaptation to market evolution and the possibility of early entry in new markets. New technologies that are developed either for terrestrial networks or for space defense applications would become soon available to satellite and equipment manufacturers. A skilful mix of these new technologies with the older and more mature ones should boost satellite performances and bring flexibility to the new generation of communication satellites. This paper reviews the economical and technical environment of the space communication business for the next decade. It identifies the needs and levels of flexibility that are required by the market but also allowed by technologies, in both a top-down and bottom-up approach.

Uses of communication satellites in water utility operations

Science.gov (United States)

Tighe, W. S.

This paper proposes a system to serve the communications needs of the operating side of a water utility and estimates the requirements and capabilities of the equipment needed. The system requires the shared use of a satellite transponder with 100% backup. Messages consist of data packets containing data and control information, plus voice transmission. Satellite communication may have a price advantage in some instances over wire line or VHF radio and have greater survivability in case of a natural disaster. Water and other utilities represent a significant market for low cost mass produced satellite earth terminals.

Accurate beacon positioning method for satellite-to-ground optical communication.

Science.gov (United States)

Wang, Qiang; Tong, Ling; Yu, Siyuan; Tan, Liying; Ma, Jing

2017-12-11

In satellite laser communication systems, accurate positioning of the beacon is essential for establishing a steady laser communication link. For satellite-to-ground optical communication, the main influencing factors on the acquisition of the beacon are background noise and atmospheric turbulence. In this paper, we consider the influence of background noise and atmospheric turbulence on the beacon in satellite-to-ground optical communication, and propose a new locating algorithm for the beacon, which takes the correlation coefficient obtained by curve fitting for image data as weights. By performing a long distance laser communication experiment (11.16 km), we verified the feasibility of this method. Both simulation and experiment showed that the new algorithm can accurately obtain the position of the centroid of beacon. Furthermore, for the distortion of the light spot through atmospheric turbulence, the locating accuracy of the new algorithm was 50% higher than that of the conventional gray centroid algorithm. This new approach will be beneficial for the design of satellite-to ground optical communication systems.

Development of Mission and Spacecraft Dynamics Analysis System for Geostationary Communication Satellite

Directory of Open Access Journals (Sweden)

Hyeon Cheol Gong

1998-06-01

Full Text Available We consider the motion of the subsystems as separate bodies as well as the entire satellite for the attitude and orbit control of a communication satellite by multi-body modeling technique. Thus, the system can be applied to a general communication satellite as well as a specific communication satellite, i.e. Koreasat I, II. The simulation results can be viewed by two-dimensional graphics and three-dimensional animation. The graphical user interface (GUI makes its usage much simpler. We have simulated a couple of scenarios for Koreasat I, II which are being operated as geostationary communication satellites to verify the system performance.

Some design considerations for planetary relay communications satellites.

Science.gov (United States)

Barber, T. A.; Bourke, R. D.

1966-01-01

Items affecting information transmitted from payload landed on remote planet to Earth via communications satellite including orbit, transmission policy and orbit injection error effect on communication capability

Advanced Communications Technology Satellite (ACTS) and potential system applications

Science.gov (United States)

Wright, David L.; Balombin, Joseph R.; Sohn, Philip Y.

1990-01-01

A description of the advanced communications technology satellite (ACTS) system is given with special emphasis on the communication characteristics. Potential satellite communications scenarios, including future operational ACTS-like satellite systems, are discussed. The description of the ACTS system updates previously published ACTS system references. Detailed information on items such as experimental ground stations is presented. The potential services can be generically described as voice, video, and data services. The implementation of these services on future operational ACTS-like systems can lead to unique quality, flexibility, and capacity characteristics at lower service costs. The specific service applications that could be supported range from low to high data rates and include both domestic and international applications.

Next generation satellite communications networks

Science.gov (United States)

Garland, P. J.; Osborne, F. J.; Streibl, I.

The paper introduces two potential uses for new space hardware to permit enhanced levels of signal handling and switching in satellite communication service for Canada. One application involves increased private-sector services in the Ku band; the second supports new personal/mobile services by employing higher levels of handling and switching in the Ka band. First-generation satellite regeneration and switching experiments involving the NASA/ACTS spacecraft are described, where the Ka band and switching satellite network problems are emphasized. Second-generation satellite development is outlined based on demand trends for more packet-based switching, low-cost earth stations, and closed user groups. A demonstration mission for new Ka- and Ku-band technologies is proposed, including the payload configuration. The half ANIK E payload is shown to meet the demonstration objectives, and projected to maintain a fully operational payload for at least 10 years.

Scheduling algorithm for data relay satellite optical communication based on artificial intelligent optimization

Science.gov (United States)

Zhao, Wei-hu; Zhao, Jing; Zhao, Shang-hong; Li, Yong-jun; Wang, Xiang; Dong, Yi; Dong, Chen

2013-08-01

Optical satellite communication with the advantages of broadband, large capacity and low power consuming broke the bottleneck of the traditional microwave satellite communication. The formation of the Space-based Information System with the technology of high performance optical inter-satellite communication and the realization of global seamless coverage and mobile terminal accessing are the necessary trend of the development of optical satellite communication. Considering the resources, missions and restraints of Data Relay Satellite Optical Communication System, a model of optical communication resources scheduling is established and a scheduling algorithm based on artificial intelligent optimization is put forwarded. According to the multi-relay-satellite, multi-user-satellite, multi-optical-antenna and multi-mission with several priority weights, the resources are scheduled reasonable by the operation: "Ascertain Current Mission Scheduling Time" and "Refresh Latter Mission Time-Window". The priority weight is considered as the parameter of the fitness function and the scheduling project is optimized by the Genetic Algorithm. The simulation scenarios including 3 relay satellites with 6 optical antennas, 12 user satellites and 30 missions, the simulation result reveals that the algorithm obtain satisfactory results in both efficiency and performance and resources scheduling model and the optimization algorithm are suitable in multi-relay-satellite, multi-user-satellite, and multi-optical-antenna recourses scheduling problem.

Reusable Communication Infrastructure for Small Satellites

Data.gov (United States)

National Aeronautics and Space Administration — The research goal of this project is to develop a comprehensive communications reference architecture that is applicable to a wide variety of small satellite...

Effect of Ionosphere on Geostationary Communication Satellite Signals

Science.gov (United States)

Erdem, Esra; Arikan, Feza; Gulgonul, Senol

2016-07-01

Geostationary orbit (GEO) communications satellites allow radio, television, and telephone transmissions to be sent live anywhere in the world. They are extremely important in daily life and also for military applications. Since, satellite communication is an expensive technology addressing crowd of people, it is critical to improve the performance of this technology. GEO satellites are at 35,786 kilometres from Earth's surface situated directly over the equator. A satellite in a geostationary orbit (GEO) appears to stand still in the sky, in a fixed position with respect to an observer on the earth, because the satellite's orbital period is the same as the rotation rate of the Earth. The advantage of this orbit is that ground antennas can be fixed to point towards to satellite without their having to track the satellite's motion. Radio frequency ranges used in satellite communications are C, X, Ku, Ka and even EHG and V-band. Satellite signals are disturbed by atmospheric effects on the path between the satellite and the receiver antenna. These effects are mostly rain, cloud and gaseous attenuation. It is expected that ionosphere has a minor effect on the satellite signals when the ionosphere is quiet. But there are anomalies and perturbations on the structure of ionosphere with respect to geomagnetic field and solar activity and these conditions may cause further affects on the satellite signals. In this study IONOLAB-RAY algorithm is adopted to examine the effect of ionosphere on satellite signals. IONOLAB-RAY is developed to calculate propagation path and characteristics of high frequency signals. The algorithm does not have any frequency limitation and models the plasmasphere up to 20,200 km altitude, so that propagation between a GEO satellite and antenna on Earth can be simulated. The algorithm models inhomogeneous, anisotropic and time dependent structure of the ionosphere with a 3-D spherical grid geometry and calculates physical parameters of the

New Channel Coding Methods for Satellite Communication

Directory of Open Access Journals (Sweden)

J. Sebesta

2010-04-01

Full Text Available This paper deals with the new progressive channel coding methods for short message transmission via satellite transponder using predetermined length of frame. The key benefits of this contribution are modification and implementation of a new turbo code and utilization of unique features with applications of methods for bit error rate estimation and algorithm for output message reconstruction. The mentioned methods allow an error free communication with very low Eb/N0 ratio and they have been adopted for satellite communication, however they can be applied for other systems working with very low Eb/N0 ratio.

Gigabit Satellite Network for NASA's Advanced Communication Technology Satellite (ACTS)

Science.gov (United States)

Hoder, Douglas; Bergamo, Marcos

1996-01-01

The advanced communication technology satellite (ACTS) gigabit satellite network provides long-haul point-to-point and point-to-multipoint full-duplex SONET services over NASA's ACTS. at rates up to 622 Mbit/s (SONET OC-12), with signal quality comparable to that obtained with terrestrial fiber networks. Data multiplexing over the satellite is accomplished using time-division multiple access (TDMA) techniques coordinated with the switching and beam hopping facilities provided by ACTS. Transmissions through the satellite are protected with Reed-Solomon encoding. providing virtually error-free transmission under most weather conditions. Unique to the system are a TDMA frame structure and satellite synchronization mechanism that allow: (a) very efficient utilization of the satellite capacity: (b) over-the-satellite dosed-loop synchronization of the network in configurations with up to 64 ground stations: and (c) ground station initial acquisition without collisions with existing signalling or data traffic. The user interfaces are compatible with SONET standards, performing the function of conventional SONET multiplexers and. as such. can be: readily integrated with standard SONET fiber-based terrestrial networks. Management of the network is based upon the simple network management protocol (SNMP). and includes an over-the-satellite signalling network and backup terrestrial internet (IP-based) connectivity. A description of the ground stations is also included.

COMMUNICATION SATELLITES FOR EDUCATION, SCIENCE AND CULTURE. REPORTS AND PAPERS ON MASS COMMUNICATION, NO. 53.

Science.gov (United States)

SCHRAMM, WILBUR

THE TECHNOLOGY OF COMMUNICATION SATELLITES IS SUFFICIENTLY ADVANCED THAT CONCERNED AGENCIES, SUCH AS UNESCO, SHOULD BEGIN TO PLAN FOR THEIR USE IN EXCHANGE OF DATA, NEWS TRANSMISSION, CULTURAL EXCHANGE, AND EDUCATION. GROUNDWORK IN TECHNOLOGY, IN THE DESIGN OF A SATELLITE COMMUNICATION SYSTEM, IN VALUE JUDGMENTS, IN AGREEMENTS OF COOPERATION AND…

DOA estimation for attitude determination on communication satellites

Directory of Open Access Journals (Sweden)

Yang Bin

2014-06-01

Full Text Available In order to determine an appropriate attitude of three-axis stabilized communication satellites, this paper describes a novel attitude determination method using direction of arrival (DOA estimation of a ground signal source. It differs from optical measurement, magnetic field measurement, inertial measurement, and global positioning system (GPS attitude determination. The proposed method is characterized by taking the ground signal source as the attitude reference and acquiring attitude information from DOA estimation. Firstly, an attitude measurement equation with DOA estimation is derived in detail. Then, the error of the measurement equation is analyzed. Finally, an attitude determination algorithm is presented using a dynamic model, the attitude measurement equation, and measurement errors. A developing low Earth orbit (LEO satellite which tests mobile communication technology with smart antennas can be stabilized in three axes by corporately using a magnetometer, reaction wheels, and three-axis magnetorquer rods. Based on the communication satellite, simulation results demonstrate the effectiveness of the method. The method could be a backup of attitude determination to prevent a system failure on the satellite. Its precision depends on the number of snapshots and the input signal-to-noise ratio (SNR with DOA estimation.

Spread spectrum mobile communication experiment using ETS-V satellite

Science.gov (United States)

Ikegami, Tetsushi; Suzuki, Ryutaro; Kadowaki, Naoto; Taira, Shinichi; Sato, Nobuyasu

1990-01-01

The spread spectrum technique is attractive for application to mobile satellite communications, because of its random access capability, immunity to inter-system interference, and robustness to overloading. A novel direct sequence spread spectrum communication equipment is developed for land mobile satellite applications. The equipment is developed based on a matched filter technique to improve the initial acquisition performance. The data rate is 2.4 kilobits per sec. and the PN clock rate is 2.4552 mega-Hz. This equipment also has a function of measuring the multipath delay profile of land mobile satellite channel, making use of a correlation property of a PN code. This paper gives an outline of the equipment and the field test results with ETS-V satellite.

Next-Generation NASA Earth-Orbiting Relay Satellites: Fusing Optical and Microwave Communications

Science.gov (United States)

Israel, David J.; Shaw, Harry

2018-01-01

NASA is currently considering architectures and concepts for the generation of relay satellites that will replace the Tracking and Data Relay Satellite (TDRS) constellation, which has been flying since 1983. TDRS-M, the last of the second TDRS generation, launched in August 2017, extending the life of the TDRS constellation beyond 2030. However, opportunities exist to re-engineer the concepts of geosynchronous Earth relay satellites. The needs of the relay satellite customers have changed dramatically over the last 34 years since the first TDRS launch. There is a demand for greater bandwidth as the availability of the traditional RF spectrum for space communications diminishes and the demand for ground station access grows. The next generation of NASA relay satellites will provide for operations that have factored in these new constraints. In this paper, we describe a heterogeneous constellation of geosynchronous relay satellites employing optical and RF communications. The new constellation will enable new optical communications services formed by user-to-space relay, space relay-to-space relay and space relay-to-ground links. It will build upon the experience from the Lunar Laser Communications Demonstration from 2013 and the Laser Communications Relay Demonstration to be launched in 2019.Simultaneous to establishment of the optical communications space segment, spacecraft in the TDRS constellation will be replaced with RF relay satellites with targeted subsets of the TDRS capabilities. This disaggregation of the TDRS service model will allow for flexibility in replenishing the needs of legacy users as well as addition of new capabilities for future users. It will also permit the U.S. government access to launch capabilities such as rideshare and to hosted payloads that were not previously available.In this paper, we also explore how the next generation of Earth relay satellites provides a significant boost in the opportunities for commercial providers to the

Next-Generation NASA Earth-Orbiting Relay Satellites: Fusing Microwave and Optical Communications

Science.gov (United States)

Israel, David J.

2018-01-01

NASA is currently considering architectures and concepts for the generation of relay satellites that will replace the Tracking and Data Relay Satellite (TDRS) constellation, which has been flying since 1983. TDRS-M, the last of the second TDRS generation, launched in August 2017, extending the life of the TDRS constellation beyond 2030. However, opportunities exist to re-engineer the concepts of geosynchronous Earth relay satellites. The needs of the relay satellite customers have changed dramatically over the last 34 years since the first TDRS launch. There is a demand for greater bandwidth as the availability of the traditional RF spectrum for space communications diminishes and the demand for ground station access grows. The next generation of NASA relay satellites will provide for operations that have factored in these new constraints. In this paper, we describe a heterogeneous constellation of geosynchronous relay satellites employing optical and RF communications. The new constellation will enable new optical communications services formed by user-to-space relay, space relay-to-space relay and space relay-to-ground links. It will build upon the experience from the Lunar Laser Communications Demonstration from 2013 and the Laser Communications Relay Demonstration to be launched in 2019.Simultaneous to establishment of the optical communications space segment, spacecraft in the TDRS constellation will be replaced with RF relay satellites with targeted subsets of the TDRS capabilities. This disaggregation of the TDRS service model will allow for flexibility in replenishing the needs of legacy users as well as addition of new capabilities for future users. It will also permit the U.S. government access to launch capabilities such as rideshare and to hosted payloads that were not previously available. In this paper, we also explore how the next generation of Earth relay satellites provides a significant boost in the opportunities for commercial providers to the

Computer-Aided Communication Satellite System Analysis and Optimization.

Science.gov (United States)

Stagl, Thomas W.; And Others

Various published computer programs for fixed/broadcast communication satellite system synthesis and optimization are discussed. The rationale for selecting General Dynamics/Convair's Satellite Telecommunication Analysis and Modeling Program (STAMP) in modified form to aid in the system costing and sensitivity analysis work in the Program on…

Two-way digital communications

Science.gov (United States)

Glenn, William E.; Daly, Ed

1996-03-01

The communications industry has been rapidly converting from analog to digital communications for audio, video, and data. The initial applications have been concentrating on point-to-multipoint transmission. Currently, a new revolution is occurring in which two-way point-to-point transmission is a rapidly growing market. The system designs for video compression developed for point-to-multipoint transmission are unsuitable for this new market as well as for satellite based video encoding. A new system developed by the Space Communications Technology Center has been designed to address both of these newer applications. An update on the system performance and design will be given.

Multiquantum well beam-steering device for laser satellite communication

Science.gov (United States)

Lahat, Roee; Levy, Itamar; Shlomi, Arnon

2002-01-01

With the increasing interest in laser satellite communications, new methods are sought to solve the existing problems of accurate and rapid laser beam deflection. Current solutions in the form of galvanometers or piezo fast steering mirrors with one or two degrees of freedom are bulky, power-consuming and slow. The Multi-Quantum Well (MQW) is a semiconductor device with unique potential to steer laser beams without any moving parts. We have conducted a preliminary evaluation of the potential application of the MQW as a laser beam-steering device for laser satellite communication, examining the performance of critical parameters for this type of communications.

Satellite communications: possibilities and problems

International Nuclear Information System (INIS)

Hine, M.

1986-01-01

Communication links via satellites are becoming available in Europe, both as part of the development of the telephone system and as special services aimed at data traffic. They offer the possibility of speeds between 50 kb/s and 2 Mb/s, without the problems and long term commitments of long distance land lines. Such links are provided by the PTT's as circuits which can be booked for variable periods, and have error rates which can be very low and well controlled. Problems in networking can arise from the satellite delay, particularly if errors occur in the local connections, and from the leased circuit and tariff philosophies of the PTT's. (Auth.)

Vibration noise control in laser satellite communication

Science.gov (United States)

Saksonov, Avigdor; Shlomi, Arnon; Kopeika, Norman S.

2001-08-01

Laser satellite communication has become especially attractive in recent years. Because the laser beam width is narrow than in the RF or microwave range, the transmitted optical power may be significantly reduced. This leads to development of miniature communication systems with extremely low power consumption. On the other hand, the laser communication channel is very sensitive to vibrations of the optical platform. These vibrations cause angular noise in laser beam pointing, comparable to the laser beam width. As result, as significant portion of the optical power between transmitter and receiver is lost and the bit error rate is increased. Consequently, vibration noise control is a critical problem in laser satellite communication. The direction of the laser beam is corrected with a fast steering mirror (FSM). In this paper are presented two approaches for the FSM control. One is the feedback control that uses an LQG algorithm. The second is the direct feed- forward control when vibration noise is measured by three orthogonal accelerometers and drives directly the F SM. The performances of each approach are evaluated using MATLAB simulations.

78 FR 31576 - Enforcement Proceeding; Certain Two-Way Global Satellite Communication Devices, System and...

Science.gov (United States)

2013-05-24

...-Way Global Satellite Communication Devices, System and Components Thereof; Notice of Institution of... importation of certain two-way global satellite communication devices, system and components thereof by reason... importation any two-way global satellite communication devices, system, and components thereof that infringe...

Economic benefits of the Space Station to commercial communication satellite operators

Science.gov (United States)

Price, Kent M.; Dixson, John E.; Weyandt, Charles J.

1987-01-01

The economic and financial aspects of newly defined space-based activities, procedures, and operations (APOs) and associated satellite system designs are presented that have the potential to improve economic performance of future geostationary communications satellites. Launch insurance, launch costs, and the economics of APOs are examined. Retrieval missions and various Space Station scenarios are addressed. The potential benefits of the new APOs to the commercial communications satellite system operator are quantified.

Hybrid Maritime Satellite Communication Antenna

DEFF Research Database (Denmark)

Smith, Thomas Gunst

Hybrid antennas for a maritime satellite communication terminal with simultaneous operation at L- and Ka-band have been investigated. The frequency bands of interest are 1; 525:0 1; 660:5 MHz (RX+TX, RHCP), 19:7 20:2 (RX, LHCP) and 29:5 30:0 GHz (TX, RHCP), which are all part of the Inmarsat BGAN...

Deep space optical communication via relay satellite

Science.gov (United States)

Dolinar, S.; Vilnrotter, V.; Gagliardi, R.

1981-01-01

The application of optical communications for a deep space link via an earth-orbiting relay satellite is discussed. The system uses optical frequencies for the free-space channel and RF links for atmospheric transmission. The relay satellite is in geostationary orbit and contains the optics necessary for data processing and formatting. It returns the data to earth through the RF terrestrial link and also transmits an optical beacon to the satellite for spacecraft return pointing and for the alignment of the transmitting optics. Future work will turn to modulation and coding, pointing and tracking, and optical-RF interfacing.

Satellite switched FDMA advanced communication technology satellite program

Science.gov (United States)

Atwood, S.; Higton, G. H.; Wood, K.; Kline, A.; Furiga, A.; Rausch, M.; Jan, Y.

1982-01-01

The satellite switched frequency division multiple access system provided a detailed system architecture that supports a point to point communication system for long haul voice, video and data traffic between small Earth terminals at Ka band frequencies at 30/20 GHz. A detailed system design is presented for the space segment, small terminal/trunking segment at network control segment for domestic traffic model A or B, each totaling 3.8 Gb/s of small terminal traffic and 6.2 Gb/s trunk traffic. The small terminal traffic (3.8 Gb/s) is emphasized, for the satellite router portion of the system design, which is a composite of thousands of Earth stations with digital traffic ranging from a single 32 Kb/s CVSD voice channel to thousands of channels containing voice, video and data with a data rate as high as 33 Mb/s. The system design concept presented, effectively optimizes a unique frequency and channelization plan for both traffic models A and B with minimum reorganization of the satellite payload transponder subsystem hardware design. The unique zoning concept allows multiple beam antennas while maximizing multiple carrier frequency reuse. Detailed hardware design estimates for an FDMA router (part of the satellite transponder subsystem) indicate a weight and dc power budget of 353 lbs, 195 watts for traffic model A and 498 lbs, 244 watts for traffic model B.

The Information Revolution and International Communication

Science.gov (United States)

Day, Donald L.

1975-01-01

As a result of the growth of media, the onrushing Information Revolution has forced man into a new era - an era in which the study of media and their effects is prerequisite to understanding interaction among people. (Author)

Mission studies on constellation of LEO satellites with remote-sensing and communication payloads

Science.gov (United States)

Chen, Chia-Ray; Hwang, Feng-Tai; Hsueh, Chuang-Wei

2017-09-01

Revisiting time and global coverage are two major requirements for most of the remote sensing satellites. Constellation of satellites can get the benefit of short revisit time and global coverage. Typically, remote sensing satellites prefer to choose Sun Synchronous Orbit (SSO) because of fixed revisiting time and Sun beta angle. The system design and mission operation will be simple and straightforward. However, if we focus on providing remote sensing and store-and-forward communication services for low latitude countries, Sun Synchronous Orbit will not be the best choice because we need more satellites to cover the communication service gap in low latitude region. Sometimes the design drivers for remote sensing payloads are conflicted with the communication payloads. For example, lower orbit altitude is better for remote sensing payload performance, but the communication service zone will be smaller and we need more satellites to provide all time communication service. The current studies focus on how to provide remote sensing and communication services for low latitude countries. A cost effective approach for the mission, i.e. constellation of microsatellites, will be evaluated in this paper.

Medical image transmission via communication satellite. Evaluation of bone scintigraphy

International Nuclear Information System (INIS)

Suzuki, Hideki; Inoue, Tomio; Endo, Keigo; Shimamoto, Shigeru.

1995-01-01

As compared with terrestrial circuits, the communication satellite possesses superior characteristics such as wide area coverage, broadcasting, high capacity, and robustness to disasters. Utilizing the narrow band channel (64 kbps) of the geostationary satellite JCSAT 1 located at the altitude of 36,000 km above the equator, the authors investigated satellite-relayed medical imagings by video signals, with bone scintigraphy as a model. Each bone scintigraphy was taken by a handy-video camera, digitalized and transmitted from faculty of technology located at 25 kilometers apart from our department. Clear bone scintigraphy was obtained via satellite, as seen on the view box. Eight nuclear physicians evaluated 20 cases of bone scintigraphy. ROC (Receiver Operating Characteristic) analysis was performed between the scintigraphies on view box and via satellite by the rating method. The area under the ROC curve was 91.6±2.6% via satellite, and 93.2±2.4% on the view box and there was no significant difference between them. These results suggest that the satellite communication is very useful and effective system to send nuclear imagings to distant institutes. (author)

[Medical image transmission via communication satellite: evaluation of bone scintigraphy].

Science.gov (United States)

Suzuki, H; Inoue, T; Endo, K; Shimamoto, S

1995-10-01

As compared with terrestrial circuits, the communication satellite possesses superior characteristics such as wide area coverage, broadcasting, high capacity, and robustness to disasters. Utilizing the narrow band channel (64 kbps) of the geostationary satellite JCSAT1 located at the altitude of 36,000 km above the equator, the authors investigated satellite-relayed medical images by video signals, with bone scintigraphy as a model. Each bone scintigraphy was taken by a handy-video camera, digitalized and transmitted from faculty of technology located at 25 kilometers apart from our department. Clear bone scintigraphy was obtained via satellite, as seen on the view box. Eight nuclear physicians evaluated 20 cases of bone scintigraphy. ROC (Receiver Operating Characteristic) analysis was performed between the scintigraphies on view box and via satellite by the rating method. The area under the ROC curve was 91.6 +/- 2.6% via satellite, and 93.2 +/- 2.4% on the view box and there was no significant difference between them. These results suggest that the satellite communication is very useful and effective system to send nuclear imagings to distant institutes.

Modeling and Performance Analysis of 10 Gbps Inter-satellite Optical Wireless Communication Link

Science.gov (United States)

Singh, Mehtab

2017-12-01

Free-space optical (FSO) communication has the advantages of two of the most predominant data transmission technologies - optical fiber communication and wireless communication. Most of the technical aspects of FSO are similar to that of optical fiber communication, with major difference in the information signal propagation medium which is free space in case of FSO rather than silica glass in optical fiber communication. One of the most important applications of FSO is inter-satellite optical wireless communication (IsOWC) links which will be deployed in the future in space. The IsOWC links have many advantages over the previously existing microwave satellite communication technologies such as higher bandwidth, lower power consumption, low cost of implementation, light size, and weight. In this paper, modeling and performance analysis of a 10-Gbps inter-satellite communication link with two satellites separated at a distance of 1,200 km has been done using OPTISYSTEM simulation software. Performance has been analyzed on the basis of quality factor, signal to noise ratio (SNR), and total power of the received signal.

College curriculum-sharing via CTS. [Communications Technology Satellite

Science.gov (United States)

Hudson, H. E.; Guild, P. D.; Coll, D. C.; Lumb, D. R.

1975-01-01

Domestic communication satellites and video compression techniques will increase communication channel capacity and reduce cost of video transmission. NASA Ames Research Center, Stanford University and Carleton University are participants in an experiment to develop, demonstrate, and evaluate college course sharing techniques via satellite using video compression. The universities will exchange televised seminar and lecture courses via CTS. The experiment features real-time video compression with channel coding and quadra-phase modulation for reducing transmission bandwidth and power requirements. Evaluation plans and preliminary results of Carleton surveys on student attitudes to televised teaching are presented. Policy implications for the U.S. and Canada are outlined.

Estimating Effects Of Rain On Ground/Satellite Communication

Science.gov (United States)

Manning, R. M.

1992-01-01

LeRC-SLAM provides static and dynamic statistical assessment of impact of attenuation by rain on communication link established between Earth terminal and geosynchronous satellite. Program designed for use in specification, design, and assessment of satellite link for any terminal location in continental United States. IBM PC version written in Microsoft QuickBASIC, and Macintosh version written in Microsoft Basic.

Advanced Communication Technology Satellite (ACTS) multibeam antenna technology verification experiments

Science.gov (United States)

Acosta, Roberto J.; Larko, Jeffrey M.; Lagin, Alan R.

1992-01-01

The Advanced Communication Technology Satellite (ACTS) is a key to reaching NASA's goal of developing high-risk, advanced communications technology using multiple frequency bands to support the nation's future communication needs. Using the multiple, dynamic hopping spot beams, and advanced on board switching and processing systems, ACTS will open a new era in communications satellite technology. One of the key technologies to be validated as part of the ACTS program is the multibeam antenna with rapidly reconfigurable hopping and fixed spot beam to serve users equipped with small-aperature terminals within the coverage areas. The proposed antenna technology experiments are designed to evaluate in-orbit ACTS multibeam antenna performance (radiation pattern, gain, cross pol levels, etc.).

Modular approach for satellite communication ground terminals

Science.gov (United States)

Gould, G. R.

1984-01-01

The trend in satellite communications is toward completely digital, time division multiple access (TDMA) systems with uplink and downlink data rates dictated by the type of service offered. Trunking terminals will operate in the 550 MBPS (megabit per second) region uplink and downlink, whereas customer premise service (CPS) terminals will operate in the 25 to 10 MBPS region uplink and in the 200 MBPS region downlink. Additional criteria for the ground terminals will be to maintain clock sychronization with the system and burst time integrity to within a matter of nanoseconds, to process required order-fire information, to provide adaptive data scrambing, and to compensate for variations in the user input output data rates, and for changes in range in the satellite communications links resulting from satellite perturbations in orbit. To achieve the required adaptability of a ground terminal to the above mentioned variables, programmable building blocks can be developed that will meet all of these requirements. To maintain system synchronization, i.e., all bursted data arriving at the satellite within assigned TDMA windows, ground terminal transmit data rates and burst timing must be maintained within tight tolerances. With a programmable synchronizer as the heart of the terminal timing generation, variable data rates and burst timing tolerances are achievable. In essence, the unit inputs microprocessor generated timing words and outputs discrete timing pulses.

Advanced domestic digital satellite communications systems experiments

Science.gov (United States)

Iso, A.; Izumisawa, T.; Ishida, N.

1984-02-01

The characteristics of advanced digital transmission systems were measured, using newly developed small earth stations and a K-band and C-band communication satellite. Satellite link performance for data, facsimile, video and packet switching information transmission at bit rates ranging from 6.4 kbit/s to 6.3 Mbit/s have been confirmed, using a small K-band earth station and a demand-assignment time division multiple access system. A low-capacity omni-use C-band terminal experiment has verified a telephone channel transmission performance by spread-spectrum multiple access. Single point to multipoint transmission characteristics of the 64 kbit/s data signals from the computer center were tested, using a receive-only 4 GHz earth terminal. Basic satellite link performance was confirmed under clear-sky conditions. Precise satellite orbit and attitude keeping experiments were carried out to obtain precise satellite antenna pointing accuracy for development of K-band earth stations that do not require satellite tracking equipment. Precise station keeping accuracy of 0.02 degrees was obtained.

The ACTS Flight System - Cost-Effective Advanced Communications Technology. [Advanced Communication Technology Satellite

Science.gov (United States)

Holmes, W. M., Jr.; Beck, G. A.

1984-01-01

The multibeam communications package (MCP) for the Advanced Communications Technology Satellite (ACTS) to be STS-launched by NASA in 1988 for experimental demonstration of satellite-switched TDMA (at 220 Mbit/sec) and baseband-processor signal routing (at 110 or 27.5 Mbit/sec) is characterized. The developmental history of the ACTS, the program definition, and the spacecraft-bus and MCP parameters are reviewed and illustrated with drawings, block diagrams, and maps of the coverage plan. Advanced features of the MPC include 4.5-dB-noise-figure 30-GHz FET amplifiers and 20-GHz TWTA transmitters which provide either 40-W or 8-W RF output, depending on rain conditions. The technologies being tested in ACTS can give frequency-reuse factors as high as 20, thus greatly expanding the orbit/spectrum resources available for U.S. communications use.

Key issues of multiple access technique for LEO satellite communication systems

Institute of Scientific and Technical Information of China (English)

温萍萍; 顾学迈

2004-01-01

The large carrier frequency shift caused by the high-speed movement of satellite (Doppler effects) and the propagation delay on the up-down link are very critical issues in an LEO satellite communication system, which affects both the selection and the implementation of a suitable access method. A Doppler based multiple access technique is used here to control the flow and an MPRMA-HS protocol is proposed for the application in LEO satellite communication systems. The extended simulation trials prove that the proposed scheme seems to be a very promising access method.

Study to forecast and determine characteristics of world satellite communications market

Science.gov (United States)

Filep, R. T.; Schnapf, A.; Fordyce, S. W.

1983-01-01

The world commercial communications satellite market during the spring and summer of 1983 was examined and characteristics and forecasts of the market extending to the year 2000 were developed. Past, present and planned satellites were documented in relation to frequencies, procurement and launch dates, costs, transponders, and prime contractor. Characteristics of the market are outlined for the periods 1965 - 1985, 1986 - 1989, and 1990 - 2000. Market share forecasts, discussions of potential competitors in various world markets, and profiles of major communication satellite manufacturing and user countries are documented.

TWT design requirements for 30/20 GHz digital communications' satellite

Science.gov (United States)

Stankiewicz, N.; Anzic, G.

1979-01-01

The rapid growth of communication traffic (voice, data, and video) requires the development of additional frequency bands before the 1990's. The frequencies currently in use for satellite communications at 6/4 GHz are crowded and demands for 14/12 GHz systems are increasing. Projections are that these bands will be filled to capacity by the late 1980's. The next higher frequency band allocated for satellite communications is at 30/20 GHz. For interrelated reasons of efficiency, power level, and system reliability criteria, a candidate for the downlink amplifier in a 30/20 GHz communications' satellite is a dual mode traveling wave tube (TWT) equipped with a highly efficient depressed collector. A summary is given of the analyses which determine the TWT design requirements. The overall efficiency of such a tube is then inferred from a parametric study and from experimental data on multistaged depressed collectors. The expected TWT efficiency at 4 dB below output saturation is 24 percent in the high mode and 22 percent in the low mode.

Antennas for mobile satellite communications

Science.gov (United States)

Huang, John

1991-12-01

A NASA sponsored program, called the Mobile Satellite (MSAT) system, has prompted the development of several innovative antennas at L-band frequencies. In the space segment of the MSAT system, an efficient, light weight, circularly polarized microstrip array that uses linearly polarized elements was developed as a multiple beam reflector feed system. In the ground segment, a low-cost, low-profile, and very efficient microstrip Yagi array was developed as a medium-gain mechanically steered vehicle antenna. Circularly shaped microstrip patches excited at higher-order modes were also developed as low-gain vehicle antennas. A more recent effort called for the development of a 20/30 GHz mobile terminal antenna for future-generation mobile satellite communications. To combat the high insertion loss encountered at 20/30 GHz, series-fed Monolithic Microwave Integrated Circuit (MMIC) microstrip array antennas are currently being developed. These MMIC arrays may lead to the development of several small but high-gain Ka-band antennas for the Personal Access Satellite Service planned for the 2000s.

Pulp science: education and communication in the paperback book revolution.

Science.gov (United States)

Gormley, Melinda

2016-03-01

Paperback books on scientific topics were a hot commodity in the United States from the 1940s to 1960s providing a vehicle for science communication that transformed science education. Well-known scientists authored them, including Rachel Carson, Theodosius Dobzhansky, George Gamow, Fred Hoyle, Julian Huxley, and Margaret Mead. A short history of 'the paperback revolution' that began in the 1930s is provided before concentrating on one publishing company based in New York City, the New American Library of World Literature (NAL), which produced Signet and Mentor Books. The infrastructure that led to the production and consumption of paperback books is described and an underexplored and not-previously identified genre of educational books on scientific topics, what the author refers to as pulp science, is characterized. Copyright © 2016 Elsevier Ltd. All rights reserved.

A demand assignment control in international business satellite communications network

Science.gov (United States)

Nohara, Mitsuo; Takeuchi, Yoshio; Takahata, Fumio; Hirata, Yasuo

An experimental system is being developed for use in an international business satellite (IBS) communications network based on demand-assignment (DA) and TDMA techniques. This paper discusses its system design, in particular from the viewpoints of a network configuration, a DA control, and a satellite channel-assignment algorithm. A satellite channel configuration is also presented along with a tradeoff study on transmission rate, HPA output power, satellite resource efficiency, service quality, and so on.

A digital simulation of message traffic for natural disaster warning communications satellite

Science.gov (United States)

Hein, G. F.; Stevenson, S. M.

1972-01-01

Various types of weather communications are required to alert industries and the general public about the impending occurrence of tornados, hurricanes, snowstorms, floods, etc. A natural disaster warning satellite system has been proposed for meeting the communications requirements of the National Oceanic and Atmospheric Administration. Message traffic for a communications satellite was simulated with a digital computer in order to determine the number of communications channels to meet system requirements. Poisson inputs are used for arrivals and an exponential distribution is used for service.

Implementation of Multiple Access Techniques Applicable for Maritime Satellite Communications

Directory of Open Access Journals (Sweden)

Stojce Dimov Ilcev

2013-12-01

Full Text Available In this paper are introduced fundamentals, characteristics, advantages and disadvantages of Multiple Access (MA employed as transmission techniques in the Maritime Mobile Satellite Communications (MMSC between ships and Coast Earth Station (CES via Geostationary Earth Orbit (GEO or Not-GEO satellite constellations. In fixed satellite communication, as a rule, especially in MMSC many users are active at the same time. The problem of simultaneous communications between many single or multipoint mobile satellite users can be solved by using MA technique, such as Frequency Division Multiple Access (FDMA, Time Division Multiple Access (TDMA, Code Division Multiple Access (CDMA, Space Division Multiple Access (SDMA and Random (Packet Division Multiple Access (RDMA. Since the resources of the systems such as the transmitting power and the bandwidth are limited, it is advisable to use the channels with complete charge and to create a different MA to the channel. This generates a problem of summation and separation of signals in the transmission and reception parts, respectively. Deciding this problem consists in the development of orthogonal channels of transmission in order to divide signals from various users unambiguously on the reception part.

ESA personal communications and digital audio broadcasting systems based on non-geostationary satellites

Science.gov (United States)

Logalbo, P.; Benedicto, J.; Viola, R.

1993-01-01

Personal Communications and Digital Audio Broadcasting are two new services that the European Space Agency (ESA) is investigating for future European and Global Mobile Satellite systems. ESA is active in promoting these services in their various mission options including non-geostationary and geostationary satellite systems. A Medium Altitude Global Satellite System (MAGSS) for global personal communications at L and S-band, and a Multiregional Highly inclined Elliptical Orbit (M-HEO) system for multiregional digital audio broadcasting at L-band are described. Both systems are being investigated by ESA in the context of future programs, such as Archimedes, which are intended to demonstrate the new services and to develop the technology for future non-geostationary mobile communication and broadcasting satellites.

77 FR 58579 - Certain Two-Way Global Satellite Communication Devices, System and Components Thereof...

Science.gov (United States)

2012-09-21

... Communication Devices, System and Components Thereof; Institution of Investigation Pursuant to 19 U.S.C. 1337... certain two-way global satellite communication devices, system and components thereof that infringe one or... within the United States after importation of certain two-way global satellite communication devices...

Communications Satellite Systems Conference, 9th, San Diego, CA, March 7-11, 1982, Collection of Technical Papers

Science.gov (United States)

The Shuttle-to-Geostationary Orbital Transfer by mid-level thrust is considered along with multibeam antenna concepts for global communications, the antenna pointing systems for large communication satellites, the connection phase of multidestination protocols for broadcast satellites, and an experiment in high-speed international packet switching. Attention is given to a dynamic switch matrix for the TDMA satellite switching system, the characterization of 16 bit microprocessors for space use, in-orbit operation and test of Intelsat V satellites, the first operational communications system via satellite in Europe, the Arab satellite communications systems, second generation business satellite systems for Europe, and a high performance Ku-band satellite for the 1980's. Other topics investigated are related to Ku-band terminal design tradeoffs, progress in the definition of the Italian satellite for domestic telecommunications, future global satellite systems for Intelsat, and satellite refuelling in orbit.

Communication Media and Educational Technology: An Overview and Assessment with Reference to Communication Satellites.

Science.gov (United States)

Ohlman, Herbert

In this survey and analysis of the present state and future trends of communication media and educational technology, particular emphasis is placed on the potential uses of communication satellites and the substitution of electronic transmission for physical distribution of educational materials. The author analyzes in detail the characteristics…

Investigation of multipactor breakdown in communication satellite

Indian Academy of Sciences (India)

Multipactor breakdown or multipactor discharge is a form of high frequency discharge that may occur in microwave components operating at very low pressures. Some RF components of multi-channel communication satellites have co-axial geometry and handle high RF power under near-vacuum conditions.

A Study on Fuel Estimation Algorithms for a Geostationary Communication & Broadcasting Satellite

Directory of Open Access Journals (Sweden)

Jong Won Eun

2000-12-01

Full Text Available It has been developed to calculate fuel budget for a geostationary communication and broadcasting satellite. It is quite essential that the pre-launch fuel budget estimation must account for the deterministic transfer and drift orbit maneuver requirements. After on-station, the calculation of satellite lifetime should be based on the estimation of remaining fuel and assessment of actual performance. These estimations step from the proper algorithms to produce the prediction of satellite lifetime. This paper concentrates on the fuel estimation method that was studied for calculation of the propellant budget by using the given algorithms. Applications of this method are discussed for a communication and broadcasting satellite.

Spectrum and power allocation in cognitive multi-beam satellite communications with flexible satellite payloads

Science.gov (United States)

Liu, Zhihui; Wang, Haitao; Dong, Tao; Yin, Jie; Zhang, Tingting; Guo, Hui; Li, Dequan

2018-02-01

In this paper, the cognitive multi-beam satellite system, i.e., two satellite networks coexist through underlay spectrum sharing, is studied, and the power and spectrum allocation method is employed for interference control and throughput maximization. Specifically, the multi-beam satellite with flexible payload reuses the authorized spectrum of the primary satellite, adjusting its transmission band as well as power for each beam to limit its interference on the primary satellite below the prescribed threshold and maximize its own achievable rate. This power and spectrum allocation problem is formulated as a mixed nonconvex programming. For effective solving, we first introduce the concept of signal to leakage plus noise ratio (SLNR) to decouple multiple transmit power variables in the both objective and constraint, and then propose a heuristic algorithm to assign spectrum sub-bands. After that, a stepwise plus slice-wise algorithm is proposed to implement the discrete power allocation. Finally, simulation results show that adopting cognitive technology can improve spectrum efficiency of the satellite communication.

Worldwide satellite communications for the energy utility industry. Final report

International Nuclear Information System (INIS)

Skelton, R.L.

1998-07-01

Recent and future generations of low earth orbiting (LEO) satellites are promising new possibilities for using space communications to achieve operational improvements and business expansion in energy supply and delivery industries. The ability to reach remote locations with relatively inexpensive devices and infrastructure is a unique property of satellites. Applications include remote monitoring and control of distributed resources and emergency and personal communication. Satellite systems are emerging as a significant opportunity for investment minded utilities. Over a dozen groups are planning to launch a total of 1200 LEOs in the period from 1996 to 2006, at a probable cost of over $20 Billion. This large number of systems can provide a worldwide mix of narrow band and wideband services including data, voice, video and Internet access. This paper examines the two primary factors which have limited applications in the energy industry: cost and propagation delay. The former has so far limited the technology to fixed communications with a few important sites such as remote substations. The latter has rendered the technology unsuitable for applications where critical protection mechanisms are involved. These constraints are effectively countered by the emerging LEO systems. Big LEOs will be used for voice service, little LEOs will be the systems of choice for most utility data applications. The author concludes that there are good technical and business reasons to reconsider future satellite communications as an option for meeting certain strategic business objectives in power system management and customer oriented information services

Global mobile satellite communications theory for maritime, land and aeronautical applications

CERN Document Server

Ilčev, Stojče Dimov

2017-01-01

This book discusses current theory regarding global mobile satellite communications (GMSC) for maritime, land (road and rail), and aeronautical applications. It covers how these can enable connections between moving objects such as ships, road and rail vehicles and aircrafts on one hand, and on the other ground telecommunications subscribers through the medium of communications satellites, ground earth stations, Terrestrial Telecommunication Networks (TTN), Internet Service Providers (ISP) and other wireless and landline telecommunications providers. This new edition covers new developments and initiatives that have resulted in land and aeronautical applications and the introduction of new satellite constellations in non-geostationary orbits and projects of new hybrid satellite constellations. The book presents current GMSC trends, mobile system concepts and network architecture using a simple mode of style with understandable technical information, characteristics, graphics, illustrations and mathematics equ...

22 CFR 123.27 - Special licensing regime for export to U.S. allies of commercial communications satellite...

Science.gov (United States)

2010-04-01

.... allies of commercial communications satellite components, systems, parts, accessories, attachments and... export to U.S. allies of commercial communications satellite components, systems, parts, accessories... associated technical data for commercial communications satellites, and who are so registered with the...

LEOPACK The integrated services communications system based on LEO satellites

Science.gov (United States)

Negoda, A.; Bunin, S.; Bushuev, E.; Dranovsky, V.

LEOPACK is yet another LEO satellite project which provides global integrated services for 'business' communications. It utilizes packet rather then circuit switching in both terrestrial and satellite chains as well as cellular approach for frequencies use. Original multiple access protocols and decentralized network control make it possible to organize regionally or logically independent and world-wide networks. Relatively small number of satellites (28) provides virtually global network coverage.

Development of a demand assignment/TDMA system for international business satellite communications

Science.gov (United States)

Nohara, Mitsuo; Takeuchi, Yoshio; Takahata, Fumio; Hirata, Yasuo; Yamazaki, Yoshiharu

An experimental IBS (international business satellite) communications system based on a demand assignment and TDMA (time-division multiple-access) operation has been developed. The system utilizes a limited satellite resource efficiently and provides various kinds of ISDN services totally. A discussion is presented of the IBS network configurations suitable to international communications and describes the developed communications system from the viewpoint of the hardware and software implementation. The performance in terms of the transmission quality and call processing is also demonstrated.

IMT-2000 Satellite Standards with Applications to Mobile Air Traffic Communications Networks

Science.gov (United States)

Shamma, Mohammed A.

2004-01-01

The International Mobile Telecommunications - 2000 (IMT-2000) standard and more specifically the Satellite component of it, is investigated as a potential alternative for communications to aircraft mobile users en-route and in terminal area. Its application to Air Traffic Management (ATM) communication needs is considered. A summary of the specifications of IMT-2000 satellite standards are outlined. It is shown via a system research analysis that it is possible to support most air traffic communication needs via an IMT-2000 infrastructure. This technology can compliment existing, or future digital aeronautical communications technologies such as VDL2, VDL3, Mode S, and UAT.

Software defined radio (SDR) architecture for concurrent multi-satellite communications

Science.gov (United States)

Maheshwarappa, Mamatha R.

SDRs have emerged as a viable approach for space communications over the last decade by delivering low-cost hardware and flexible software solutions. The flexibility introduced by the SDR concept not only allows the realisation of concurrent multiple standards on one platform, but also promises to ease the implementation of one communication standard on differing SDR platforms by signal porting. This technology would facilitate implementing reconfigurable nodes for parallel satellite reception in Mobile/Deployable Ground Segments and Distributed Satellite Systems (DSS) for amateur radio/university satellite operations. This work outlines the recent advances in embedded technologies that can enable new communication architectures for concurrent multi-satellite or satellite-to-ground missions where multi-link challenges are associated. This research proposes a novel concept to run advanced parallelised SDR back-end technologies in a Commercial-Off-The-Shelf (COTS) embedded system that can support multi-signal processing for multi-satellite scenarios simultaneously. The initial SDR implementation could support only one receiver chain due to system saturation. However, the design was optimised to facilitate multiple signals within the limited resources available on an embedded system at any given time. This was achieved by providing a VHDL solution to the existing Python and C/C++ programming languages along with parallelisation so as to accelerate performance whilst maintaining the flexibility. The improvement in the performance was validated at every stage through profiling. Various cases of concurrent multiple signals with different standards such as frequency (with Doppler effect) and symbol rates were simulated in order to validate the novel architecture proposed in this research. Also, the architecture allows the system to be reconfigurable by providing the opportunity to change the communication standards in soft real-time. The chosen COTS solution provides a

In-Space Internet-Based Communications for Space Science Platforms Using Commercial Satellite Networks

Science.gov (United States)

Kerczewski, Robert J.; Bhasin, Kul B.; Fabian, Theodore P.; Griner, James H.; Kachmar, Brian A.; Richard, Alan M.

1999-01-01

The continuing technological advances in satellite communications and global networking have resulted in commercial systems that now can potentially provide capabilities for communications with space-based science platforms. This reduces the need for expensive government owned communications infrastructures to support space science missions while simultaneously making available better service to the end users. An interactive, high data rate Internet type connection through commercial space communications networks would enable authorized researchers anywhere to control space-based experiments in near real time and obtain experimental results immediately. A space based communications network architecture consisting of satellite constellations connecting orbiting space science platforms to ground users can be developed to provide this service. The unresolved technical issues presented by this scenario are the subject of research at NASA's Glenn Research Center in Cleveland, Ohio. Assessment of network architectures, identification of required new or improved technologies, and investigation of data communications protocols are being performed through testbed and satellite experiments and laboratory simulations.

INVESTIGATION OF ADS-B MESSAGES TRAFFIC VIA SATELLITE COMMUNICATION CHANNEL

Directory of Open Access Journals (Sweden)

Volodymyr Kharchenko

2014-12-01

Full Text Available For modelling of ADS-B messages transmition with the help of low-orbit satellite complex Іrіdіumdifferent models of communication channel "Aircraft-to-Satellites-to-Ground Stations" were built using NetCrackerProfessіonal 4.1 software. Influence of aircraft and satellites amount on average link utilization and message travellingtime was studied for telecommunication channels with intersatellite link and bent-pipe architecture. The effect ofcommunication channel "saturation" during simultaneous data transmission through a satellite communicationchannel from many planes was investigated.

Evaluation of spacecraft technology programs (effects on communication satellite business ventures), volume 1

Science.gov (United States)

Greenburg, J. S.; Gaelick, C.; Kaplan, M.; Fishman, J.; Hopkins, C.

1985-01-01

Commercial organizations as well as government agencies invest in spacecraft (S/C) technology programs that are aimed at increasing the performance of communications satellites. The value of these programs must be measured in terms of their impacts on the financial performane of the business ventures that may ultimately utilize the communications satellites. An economic evaluation and planning capability was developed and used to assess the impact of NASA on-orbit propulsion and space power programs on typical fixed satellite service (FSS) and direct broadcast service (DBS) communications satellite business ventures. Typical FSS and DBS spin and three-axis stabilized spacecraft were configured in the absence of NASA technology programs. These spacecraft were reconfigured taking into account the anticipated results of NASA specified on-orbit propulsion and space power programs. In general, the NASA technology programs resulted in spacecraft with increased capability. The developed methodology for assessing the value of spacecraft technology programs in terms of their impact on the financial performance of communication satellite business ventures is described. Results of the assessment of NASA specified on-orbit propulsion and space power technology programs are presented for typical FSS and DBS business ventures.

INVESTIGATION OF ADS-B MESSAGES TRAFFIC VIA SATELLITE COMMUNICATION CHANNEL

OpenAIRE

Volodymyr Kharchenko; Wang Bo; Andrii Grekhov; Marina Kovalenko

2014-01-01

For modelling of ADS-B messages transmition with the help of low-orbit satellite complex Іrіdіumdifferent models of communication channel "Aircraft-to-Satellites-to-Ground Stations" were built using NetCrackerProfessіonal 4.1 software. Influence of aircraft and satellites amount on average link utilization and message travellingtime was studied for telecommunication channels with intersatellite link and bent-pipe architecture. The effect ofcommunication channel "saturation" during simultaneou...

NASDA'S activities and roles in promoting satellite utilization experiments

Science.gov (United States)

Shigeta, Tsutomu; Miyoshi, Takashi

2004-02-01

While NASDA has been engaged in the development of new satellite missions and the bus technologies, NASDA explores new and attractive applications by promoting the utilization of satellite missions and strengthening the relationships with external parties. Offering opportunities to external parties for conducting application experiments will bring great chances for them in challenging and experimenting new space-based applications. Consequently, it is expected that the outcomes of the space development are returned to general public, research institutes, industries, and that ideas or requirements for new satellite mission could emerge and be materialized. With these objectives in mind, NASDA is presently planning a new space project that is named "i-Space". The i-Space project aims to contribute to the progressing "IT Revolution" by providing new space communication capabilities and to develop practical applications by collaborating with external parties. This paper introduces the activities and roles of NASDA in promoting satellite utilization experiments, particularly focusing on the i-Space project.

Satellite communication transponders and their reliability; Eisei tosai tsushin kiki oyobi shinraisei ni tsuite

Energy Technology Data Exchange (ETDEWEB)

Ogawa, H [NTT Wireless System Laboratories, Kanagawa (Japan)

1994-11-01

The Engineering Test Satellite-VI is a large composite test satellite weighing two tons to perform different communication experiments. Adoption of the multi-beam satellite communication system has made possible to increase the transmission capacity, reduce the sizes of earth stations, and utilize frequencies more effectively. This paper describes the configuration of the relaying devices mounted thereon, the newly developed circuit technologies, and their reliability. The multi-beam satellite communication system mounts a number of transponders, with the frequency bands used divided into the 2.6/2.5 GHz band between the moving body and the satellite, the 6/4 GHz band for the channels between the earth stations and the satellite, and the 30/20 GHz band for the fixed communications. These arrangements were intended to achieve large size reduction as a result of applying the integrated circuit technology. The transmitters and the receivers corresponding to each beam are connected by using the satellite switches (16 inputs {times} 12 outputs). The parts used were general purpose ones rather than those specified in the MIL standards because of their number having reached so huge. Their reliability was ensured by long-term burn-in operations. 5 refs., 6 figs., 1 tab.

First satellite mobile communication trials using BLQS-CDMA

Science.gov (United States)

Luzdemateo, Maria; Johns, Simon; Dothey, Michel; Vanhimbeeck, Carl; Deman, Ivan; Wery, Bruno

1993-01-01

In this paper, technical results obtained in the first MSBN Land mobile technical trial are reported. MSBN (Mobile Satellite Business Network) is a new program undertaken by the European Space Agency (ESA) to promote mobile satellite communication in Europe, in particular voice capability. The first phase of the MSBN system implementation plan is an experimental phase. Its purpose is to evaluate through field experiments the performance of the MSBN system prior to finalization of its specifications. Particularly, the objective is to verify in the field and possibly improve the performance of the novel satellite access technique BLQS-CDMA (Band Limited Quasi-Synchronous-Code Division Multiple Access), which is proposed as baseline for the MSBN.

Navigating the Information Revolution: Choices for Laggard Countries

Science.gov (United States)

Gatune, Julius

2007-01-01

The rapid diffusion of information and communication technologies (ICTs) during the last two decades has had a profound impact on all spheres of human endeavors, changes that are collectively referred to as the Information Revolution (IR). But the revolution has been uneven, with some countries being far ahead and others far behind in IR,…

Application of communications satellites to educational development. [technology utilization/information systems - bibliographies

Science.gov (United States)

Morgan, R. P.

1975-01-01

A summary of research is presented. The broad objectives of this interdisciplinary research effort were: (1) to assess the role of satellite communications as a means of improving education in the United States, as well as in less-developed areas of the world; (2) to generate basic knowledge which will aid in making rational decisions about satellite application in the field of education in the years ahead; (3) to devise systems and strategies for improving education; and (4) to educate individuals who will be knowledgeable about aspects of satellite communications policy which transcend any single discipline.

Satellite communications for the next generation telecommunication services and networks

Science.gov (United States)

Chitre, D. M.

1991-01-01

Satellite communications can play an important role in provisioning the next-generation telecommunication services and networks, provided the protocols specifying these services and networks are satellite-compatible and the satellite subnetworks, consisting of earth stations interconnected by the processor and the switch on board the satellite, interwork effectively with the terrestrial networks. The specific parameters and procedures of frame relay and broadband integrated services digital network (B-ISDN) protocols which are impacted by a satellite delay. Congestion and resource management functions for frame relay and B-ISDN are discussed in detail, describing the division of these functions between earth stations and on board the satellite. Specific onboard and ground functions are identified as potential candidates for their implementation via neural network technology.

Air traffic management system design using satellite based geo-positioning and communications assets

Science.gov (United States)

Horkin, Phil

1995-01-01

The current FAA and ICAO FANS vision of Air Traffic Management will transition the functions of Communications, Navigation, and Surveillance to satellite based assets in the 21st century. Fundamental to widespread acceptance of this vision is a geo-positioning system that can provide worldwide access with best case differential GPS performance, but without the associated problems. A robust communications capability linking-up aircraft and towers to meet the voice and data requirements is also essential. The current GPS constellation does not provide continuous global coverage with a sufficient number of satellites to meet the precision landing requirements as set by the world community. Periodic loss of the minimum number of satellites in view creates an integrity problem, which prevents GPS from becoming the primary system for navigation. Furthermore, there is reluctance on the part of many countries to depend on assets like GPS and GLONASS which are controlled by military communities. This paper addresses these concerns and provides a system solving the key issues associated with navigation, automatic dependent surveillance, and flexible communications. It contains an independent GPS-like navigation system with 27 satellites providing global coverage with a minimum of six in view at all times. Robust communications is provided by a network of TDMA/FDMA communications payloads contained on these satellites. This network can support simultaneous communications for up to 30,000 links, nearly enough to simultaneously support three times the current global fleet of jumbo air passenger aircraft. All of the required hardware is directly traceable to existing designs.

Comparison of TCeMA and TDMA for Inter-Satellite Communications using OPNET Simulation

Science.gov (United States)

Hain, Regina Rosales; Ramanathan, Ram; Bergamo, Marcos; Wallett, Thomas M.

2003-01-01

A robust data link protocol, enabling unique physical and MAC layer technologies and sub-network level protocols, is needed in order to take advantage of the full potential of using both TDMA and CDMA in a satellite communication network. A novel MAC layer protocol, TDMA with CDMA-encoding multiple access (TCeMA) integrated with null-steered digital beam-forming spatial multiplexing, is investigated to support flexible spacecraft communications. Abstract models of the TCeMA and TDMA processes are developed in OPNFiT and a comparison of the performances of TCeMA and TDMA in a satellite network simulation are made. TCeMA provides the better connectivity and capacity with respect to TDMA for satellite communication traffic.

The C3PO project: a laser communication system concept for small satellites

Science.gov (United States)

d'Humières, Benoît; Esmiller, Bruno; Gouy, Yann; Steck, Emilie; Quintana, Crisanto; Faulkner, Graham; O'Brien, Dominic; Sproll, Fabian; Wagner, Paul; Hampf, Daniel; Riede, Wolfgang; Salter, Michael; Wang, Qin; Platt, Duncan; Jakonis, Darius; Piao, Xiaoyu; Karlsson, Mikael; Oberg, Olof; Petermann, Ingemar; Michalkiewicz, Aneta; Krezel, Jerzy; Debowska, Anna; Thueux, Yoann

2017-02-01

The satellite market is shifting towards smaller (micro and nanosatellites), lowered mass and increased performance platforms. Nanosatellites and picosatellites have been used for a number of new, innovative and unique payloads and missions. This trend requires new concepts for a reduced size, a better performance/weight ratio and a reduction of onboard power consumption. In this context, disruptive technologies, such as laser-optical communication systems, are opening new possibilities. This paper presents the C3PO1 system, "advanced Concept for laser uplink/ downlink CommuniCation with sPace Objects", and the first results of the development of its key technologies. This project targets the design of a communications system that uses a ground-based laser to illuminate a satellite, and a Modulating Retro-Reflector (MRR) to return a beam of light modulated by data to the ground. This enables a downlink, without a laser source on the satellite. This architecture suits well to small satellite applications so as high data rates are potentially provided with very low board mass. C3PO project aims to achieve data rates of 1Gbit/s between LEO satellites and Earth with a communication payload mass of less than 1kilogram. In this paper, results of the initial experiments and demonstration of the key technologies will be shown.

An up-link power control for demand assignment International Business Satellite Communications Network

Science.gov (United States)

Nohara, Mitsuo; Takeuchi, Yoshio; Takahata, Fumio

Up-link power control (UPC) is one of the essential technologies to provide efficient satellite communication systems operated at frequency bands above 10 GHz. A simple and cost-effective UPC scheme applicable to a demand assignment international business satellite communications system has been developed. This paper presents the UPC scheme, including the hardware implementation and its performance.

Integration of Satellite and Terrestrial Systems in Future Multimedia Communications

OpenAIRE

Evans, Barry; Werner, Markus; Lutz, Erich; Bousquet, Michel; Corazza, Giovanni E; Maral, Gerard; Rumeau, Robert; Ferro, Erina

2005-01-01

In this article we examine the role of satellite communications in future telecommunication networks and service provision. Lessons from the past indicate that satellites are successful as a result of their wide area coverage or speed to market for new services. Niche areas such as coverage of air and sea will persist, but for land masses convergence of fixed, mobile, and broadcasting will dictate that the only way forward for satellites is in an integrated format with terrestrial systems. We...

An Analysis of Military Use of Commercial Satellite Communications

National Research Council Canada - National Science Library

Forest, Benjamin D

2008-01-01

Since the Gulf War of 1991, United States military satellite communication (SATCOM) bandwidth demand has increased dramatically, as evidenced by recent usage rates in Operation Enduring Freedom and Operation Iraqi Freedom...

NASA/DARPA advanced communications technology satellite project for evaluation of telemedicine outreach using next-generation communications satellite technology: Mayo Foundation participation.

Science.gov (United States)

Gilbert, B K; Mitchell, M P; Bengali, A R; Khandheria, B K

1999-08-01

To describe the development of telemedicine capabilities-application of remote consultation and diagnostic techniques-and to evaluate the feasibility and practicality of such clinical outreach to rural and underserved communities with limited telecommunications infrastructures. In 1992, Mayo Foundation (Rochester, Minn, Jacksonville, Fla, and Scottsdale, Ariz), the National Aeronautics and Space Administration, and the Defense Advanced Research Projects Agency collaborated to create a complex network of fiberoptic landlines, video recording systems, satellite terminals, and specially developed data translators linking Mayo sites with other locations in the continental United States on an on-demand basis. The purpose was to transmit data via the asynchronous transfer mode (ATM) digital communications protocol over the Advanced Communications Technology Satellite. The links were intended to provide a conduit for transmission of data for patient-specific consultations between physicians, evaluation of medical imagery, and medical education for clinical staffs at remote sites. Low-data-rate (LDR) experiments went live late in 1993. Mayo Clinic Rochester successfully provided medical consultation and services to 2 small regional medical facilities. High-data-rate (HDR) experiments included studies of remote digital echocardiography, store-and-forward telemedicine, cardiac catheterization, and teleconsultation for congenital heart disease. These studies combined landline data transmission with use of the satellite. The complexity of the routing paths and network components, immaturity of available software, and inexperience with existing telecommunications caused significant study delays. These experiments demonstrated that next-generation satellite technology can provide batch and real-time imagery for telemedicine. The first-generation of the ATM and satellite network technology used in these experiments created several technical problems and inconveniences that should

Rural applications of Advanced Traveler Information Systems : evaluation of satellite communications systems for mayday applications

Science.gov (United States)

This report documents the results of an evaluation of satellite communication systems for mayday applications conducted as part of the Rural Applications of Advanced Traveler Information Systems (ATIS) study. It focuses on satellite communications sy...

Estimation of the demand for public services communications. [market research and economic analysis for a communications satellite system

Science.gov (United States)

1976-01-01

Market analyses and economic studies are presented to support NASA planning for a communications satellite system to provide public services in health, education, mobile communications, data transfer, and teleconferencing.

Integration of Commercial Mobile Satellite Services into Naval Communications

National Research Council Canada - National Science Library

Stone, Cary

1997-01-01

Mobile Satellite Services (MSS) need to be integrated into Naval Communications. DoD SATCOM military owned systems fall well short of meeting DoD SATCOM requirements in general and mobile SATCOM specifically...

Application of adaptive antenna techniques to future commercial satellite communication

Science.gov (United States)

Ersoy, L.; Lee, E. A.; Matthews, E. W.

1987-01-01

The purpose of this contract was to identify the application of adaptive antenna technique in future operational commercial satellite communication systems and to quantify potential benefits. The contract consisted of two major subtasks. Task 1, Assessment of Future Commercial Satellite System Requirements, was generally referred to as the Adaptive section. Task 2 dealt with Pointing Error Compensation Study for a Multiple Scanning/Fixed Spot Beam Reflector Antenna System and was referred to as the reconfigurable system. Each of these tasks was further sub-divided into smaller subtasks. It should also be noted that the reconfigurable system is usually defined as an open-loop system while the adaptive system is a closed-loop system. The differences between the open- and closed-loop systems were defined. Both the adaptive and reconfigurable systems were explained and the potential applications of such systems were presented in the context of commercial communication satellite systems.

Servicing communication satellites in geostationary orbit

Science.gov (United States)

Russell, Paul K.; Price, Kent M.

1990-01-01

The econmic benefits of a LEO space station are quantified by identifying alternative operating scenarios utilizing the space station's transportation facilities and assembly and repair facilities. Particular consideration is given to the analysis of the impact of on-orbit assembly and servicing on a typical communications satellite is analyzed. The results of this study show that on-orbit servicing can increase the internal rate of return by as much as 30 percent.

The electronics revolution inventing the future

CERN Document Server

Williams, J B

2017-01-01

This book is about how electronics, computing, and telecommunications have profoundly changed our lives – the way we work, live, and play. It covers a myriad of topics from the invention of the fundamental devices, and integrated circuits, through radio and television, to computers, mobile telephones and GPS. Today our lives are ruled by electronics as they control the home and computers dominate the workspace. We walk around with mobile phones and communicate by email. Electronics didn’t exist until into the twentieth century. The industrial revolution is the term usually applied to the coming of steam, railways and the factory system. In the twentieth century, it is electronics that has changed the way we gather our information, entertain ourselves, communicate and work. This book demonstrates that this is, in fact, another revolution. .

Global communication using a constellation of low earth meridian orbits

Science.gov (United States)

Oli, P. V. S.; Nagarajan, N.; Rayan, H. R.

1993-07-01

The concept of 'meridian orbits' is briefly reviewed. It is shown that, if a satellite in the meridian orbit makes an odd number of revolutions per day, then the satellite passes over the same set of meridians twice a day. Satellites in such orbits pass over the same portion of the sky twice a day and every day. This enables a user to adopt a programmed mode of tracking, thereby avoiding a computational facility for orbit prediction, look angle generation, and auto tracking. A constellation of 38 or more satellites placed in a 1200 km altitude circular orbit is favorable for global communications due to various factors. It is shown that appropriate phasing in right ascension of the ascending node and mean anomaly results in a constellation, wherein each satellite appears over the user's horizon one satellite after another. Visibility and coverage plots are provided to verify the continuous coverage.

Optimization of Power Allocation for Multiusers in Multi-Spot-Beam Satellite Communication Systems

Directory of Open Access Journals (Sweden)

Heng Wang

2014-01-01

Full Text Available In recent years, multi-spot-beam satellite communication systems have played a key role in global seamless communication. However, satellite power resources are scarce and expensive, due to the limitations of satellite platform. Therefore, this paper proposes optimizing the power allocation of each user in order to improve the power utilization efficiency. Initially the capacity allocated to each user is calculated according to the satellite link budget equations, which can be achieved in the practical satellite communication systems. The problem of power allocation is then formulated as a convex optimization, taking account of a trade-off between the maximization of the total system capacity and the fairness of power allocation amongst the users. Finally, an iterative algorithm based on the duality theory is proposed to obtain the optimal solution to the optimization. Compared with the traditional uniform resource allocation or proportional resource allocation algorithms, the proposed optimal power allocation algorithm improves the fairness of power allocation amongst the users. Moreover, the computational complexity of the proposed algorithm is linear with both the numbers of the spot beams and users. As a result, the proposed power allocation algorithm is easy to be implemented in practice.

The Advanced Communications Technology Satellite (ACTS) capabilities for serving science

Science.gov (United States)

Meyer, Thomas R.

1990-01-01

Results of research on potential science applications of the NASA Advanced Communications Technology Satellite (ACTS) are presented. Discussed here are: (1) general research on communications related issues; (2) a survey of science-related activities and programs in the local area; (3) interviews of selected scientists and associated telecommunications support personnel whose projects have communications requirements; (4) analysis of linkages between ACTS functionality and science user communications activities and modes of operation; and (5) an analysis of survey results and the projection of conclusions to a national scale.

Medical image transmission via communication satellite: evaluation of ultrasonographic images.

Science.gov (United States)

Suzuki, H; Horikoshi, H; Shiba, H; Shimamoto, S

1996-01-01

As compared with terrestrial circuits, communication satellites possess superior characteristics such as wide area coverage, broadcasting functions, high capacity, and resistance to disasters. Utilizing the narrow band channel (64 kbps) of the stationary communication satellite JCSAT1 located at an altitude of 36,000 km above the equator, we investigated satelliterelayed dynamic medical images transmitted by video signals, using hepatic ultrasonography as a model. We conclude that the "variable playing speed transmission scheme" proposed by us is effective for the transmission of dynamic images in the narrow band channel. This promises to permit diverse utilization and applications for purposes such as the transmission of other types of ultrasonic images as well as remotely directed medical diagnosis and treatment.

Causal relationships between solar proton events and single event upsets for communication satellites

Science.gov (United States)

Lohmeyer, W. Q.; Cahoy, K.; Liu, Shiyang

In this work, we analyze a historical archive of single event upsets (SEUs) maintained by Inmarsat, one of the world's leading providers of global mobile satellite communications services. Inmarsat has operated its geostationary communication satellites and collected extensive satellite anomaly and telemetry data since 1990. Over the course of the past twenty years, the satellites have experienced more than 226 single event upsets (SEUs), a catch-all term for anomalies that occur in a satellite's electronics such as bit-flips, trips in power supplies, and memory changes in attitude control systems. While SEUs are seemingly random and difficult to predict, we correlate their occurrences to space weather phenomena, and specifically show correlations between SEUs and solar proton events (SPEs). SPEs are highly energetic protons that originate from solar coronal mass ejections (CMEs). It is thought that when these particles impact geostationary (GEO) satellites they can cause SEUs as well as solar array degradation. We calculate the associated statistical correlations that each SEU occurs within one day, one week, two weeks, and one month of 10 MeV SPEs between 10 - 10,000 particle flux units (pfu). However, we find that SPEs are most prevalent at solar maximum and that the SEUs on Inmarsat's satellites occur out of phase with the solar maximum. Ultimately, this suggests that SPEs are not the primary cause of the Inmarsat SEUs. A better understanding of the causal relationship between SPEs and SEUs will help the satellite communications industry develop component and operational space weather mitigation techniques as well as help the space weather community to refine radiation models.

Broadband and scalable mobile satellite communication system for future access networks

Science.gov (United States)

Ohata, Kohei; Kobayashi, Kiyoshi; Nakahira, Katsuya; Ueba, Masazumi

2005-07-01

Due to the recent market trends, NTT has begun research into next generation satellite communication systems, such as broadband and scalable mobile communication systems. One service application objective is to provide broadband Internet access for transportation systems, temporal broadband access networks and telemetries to remote areas. While these are niche markets the total amount of capacity should be significant. We set a 1-Gb/s total transmission capacity as our goal. Our key concern is the system cost, which means that the system should be unified system with diversified services and not tailored for each application. As satellites account for a large portion of the total system cost, we set the target satellite size as a small, one-ton class dry mass with a 2-kW class payload power. In addition to the payload power and weight, the mobile satellite's frequency band is extremely limited. Therefore, we need to develop innovative technologies that will reduce the weight and maximize spectrum and power efficiency. Another challenge is the need for the system to handle up to 50 dB and a wide data rate range of other applications. This paper describes the key communication system technologies; the frequency reuse strategy, multiplexing scheme, resource allocation scheme, and QoS management algorithm to ensure excellent spectrum efficiency and support a variety of services and quality requirements in the mobile environment.

Satellite Imagery Analysis for Automated Global Food Security Forecasting

Science.gov (United States)

Moody, D.; Brumby, S. P.; Chartrand, R.; Keisler, R.; Mathis, M.; Beneke, C. M.; Nicholaeff, D.; Skillman, S.; Warren, M. S.; Poehnelt, J.

2017-12-01

The recent computing performance revolution has driven improvements in sensor, communication, and storage technology. Multi-decadal remote sensing datasets at the petabyte scale are now available in commercial clouds, with new satellite constellations generating petabytes/year of daily high-resolution global coverage imagery. Cloud computing and storage, combined with recent advances in machine learning, are enabling understanding of the world at a scale and at a level of detail never before feasible. We present results from an ongoing effort to develop satellite imagery analysis tools that aggregate temporal, spatial, and spectral information and that can scale with the high-rate and dimensionality of imagery being collected. We focus on the problem of monitoring food crop productivity across the Middle East and North Africa, and show how an analysis-ready, multi-sensor data platform enables quick prototyping of satellite imagery analysis algorithms, from land use/land cover classification and natural resource mapping, to yearly and monthly vegetative health change trends at the structural field level.

Texas Telecommunication Satellite Demonstration Project. Planning Effort for Application of Communication Satellites in Education.

Science.gov (United States)

Education Service Center Region 4, Houston, TX.

The primary goal of the Texas Telecommunication Satellite Demonstration consortium is to install, operate, and evaluate a comprehensive communication service delivery system which would provide the citizens of Texas with greater opportunity for equal access to education and information. The four major objectives of the demonstration are (1) to…

Military Dependence on Commercial Satellite Communications Systems - Strength or Vulnerability

National Research Council Canada - National Science Library

Hook, Jack

1999-01-01

The military's growing dependence on commercial satellite communications systems will become a strength or vulnerability based on how well the right balance is achieved between commercial and military systems...

Optimization of communication network topology for navigation sharing among distributed satellites

Science.gov (United States)

Dang, Zhaohui; Zhang, Yulin

2013-01-01

Navigation sharing among distributed satellites is quite important for coordinated motion and collision avoidance. This paper proposes optimization methods of the communication network topology to achieve navigation sharing. The whole communication network constructing by inter-satellite links are considered as a topology graph. The aim of this paper is to find the communication network topology with minimum communication connections' number (MCCN) in different conditions. It has found that the communication capacity and the number of channels are two key parameters affecting the results. The model of MCCN topology for navigation sharing is established and corresponding method is designed. Two main scenarios, viz., homogeneous case and heterogeneous case, are considered. For the homogeneous case where each member has the same communication capacity, it designs a construction method (Algorithm 1) to find the MCCN topology. For the heterogeneous case, it introduces a modified genetic algorithm (Algorithm 2) to find the MCCN topology. When considering the fact that the number of channels is limited, the Algorithm 2 is further modified by adding a penalized term in the fitness function. The effectiveness of these algorithms is all proved in theoretical. Three examples are further tested to illustrate the methods developed in this paper.

Integration of an ion engine on the Communications Technology Satellite.

Science.gov (United States)

Payne, W. F.; Finke, R. C.

1972-01-01

An ion engine subsystem intended for satellite stationkeeping tasks is described. Ion thrusters are chosen to perform the task because the specific impulse is at least an order of magnitude higher than the commonly used reaction control jets. The higher the value of specific impulse, the greater the total impulse that can be attained for a given weight of propellant, hence cost benefits result. The integration, subsystem testing, and the operating plans for the ion engine experiment to be flown in 1975 on the Canadian Communications Technology Satellite (CTS) are described. The subsystem is designed to demonstrate north-south stationkeeping, attitude control by means of thrust vectoring, long-term space storage and restart capability, and compatibility with a high powered communications transponder.

Australia's Domestic Communication Satellite and Education: Has Education Missed the Boat?

Science.gov (United States)

White, Peter B.

Educators have been critized for being unable to develop any firm plans for the use of Australia's Domestic Communications Satellite (AUSSAT). However, conferences, talks, and papers have resulted in some significant achievements. First, it is now possible to raise issues of communications and telecommunications planning at the very highest…

A network architecture for International Business Satellite communications

Science.gov (United States)

Takahata, Fumio; Nohara, Mitsuo; Takeuchi, Yoshio

Demand Assignment (DA) control is expected to be introduced in the International Business Satellte communications (IBS) network in order to cope with a growing international business traffic. The paper discusses the DA/IBS network from the viewpoints of network configuration, satellite channel configuration and DA control. The network configuration proposed here consists of one Central Station with network management function and several Network Coordination Stations with user management function. A satellite channel configuration is also presented along with a tradeoff study on transmission bit rate, high power amplifier output power requirement, and service quality. The DA control flow and protocol based on CCITT Signalling System No. 7 are also proposed.

ACTS TDMA network control. [Advanced Communication Technology Satellite

Science.gov (United States)

Inukai, T.; Campanella, S. J.

1984-01-01

This paper presents basic network control concepts for the Advanced Communications Technology Satellite (ACTS) System. Two experimental systems, called the low-burst-rate and high-burst-rate systems, along with ACTS ground system features, are described. The network control issues addressed include frame structures, acquisition and synchronization procedures, coordinated station burst-time plan and satellite-time plan changes, on-board clock control based on ground drift measurements, rain fade control by means of adaptive forward-error-correction (FEC) coding and transmit power augmentation, and reassignment of channel capacities on demand. The NASA ground system, which includes a primary station, diversity station, and master control station, is also described.

Modulation/demodulation techniques for satellite communications. Part 1: Background

Science.gov (United States)

Omura, J. K.; Simon, M. K.

1981-01-01

Basic characteristics of digital data transmission systems described include the physical communication links, the notion of bandwidth, FCC regulations, and performance measurements such as bit rates, bit error probabilities, throughputs, and delays. The error probability performance and spectral characteristics of various modulation/demodulation techniques commonly used or proposed for use in radio and satellite communication links are summarized. Forward error correction with block or convolutional codes is also discussed along with the important coding parameter, channel cutoff rate.

77 FR 51045 - Certain Two-Way Global Satellite Communication Devices, System and Components Thereof; Notice of...

Science.gov (United States)

2012-08-23

... Certain Two-Way Global Satellite Communication Devices, System and Components Thereof, DN 2907; the... INTERNATIONAL TRADE COMMISSION [Docket No. 2907] Certain Two-Way Global Satellite Communication Devices, System and Components Thereof; Notice of Receipt of Complaint; Solicitation of Comments Relating...

The 30/20 GHz communications satellite trunking network study

Science.gov (United States)

Kolb, W.

1981-01-01

Alternative transmission media for a CONUS-wide trunking network in the years 1990 and 2000 are examined. The alternative technologies comprised fiber optic cable, conventional C- and Ku-band satellites, and 30/20 GHz satellites. Three levels of implementation were considered - a 10-city network, a 20-city network, and a 40-city network. The cities selected were the major metropolitan areas with the greatest communications demand. All intercity voice, data, and video traffic carried more than 40 miles was included in the analysis. In the optimized network, traffic transmitted less than 500 miles was found to be better served by fiber optic cable in 1990. By the year 2000, the crossover point would be down to 200 miles, assuming availability of 30/20 GHz satellites.

Utilization of photovoltaic for broadband satellite communications in rural area of Thailand

Science.gov (United States)

Jinayim, Theerawut; Mungkung, Narong; Kasayapanand, Nat

2013-06-01

Electricity, Information and Communication Technologies (ICTs) are very important not only in urban areas but also in rural areas. To provide ICTs service in rural areas, sources of electricity and communication infrastructures must be implemented. Electricity is a major condition due to the fact that all electronic devices needed it in order to power on, so that it is impossible to operate any forms of ICTs in areas where the main national grid line is unavailable. Almost rural areas of Thailand where the main national grid line is unavailable have very good sunlight intensity. Photovoltaic is the most effective renewable energy technologies in those areas for meeting electricity needed in areas that are not connected to the main national grid line. In this paper, the efficiency utilization of photovoltaic as source of electricity for broadband satellite communication systems as well as social and economic impact and quality of life of people in rural areas of Thailand are presented. The results show that most rural communities would be able to universally access to the basic telecommunications services such as internet access and public telephone via satellite communication systems. However, in some field case study, broadband internet access via satellite communication may be unnecessary for some rural communities and the most exactly rural communities needed are electricity for household usage and battery charger.

The Future of Satellite Communications. Resource Management and the Needs of Nations.

Science.gov (United States)

Hinchman, Walter R.; Dunn, D. A.

Recent events suggest that Intelsat (the 68-nation International Telecommunications Satellite Consortium) will coordinate a number of domestic and regional systems that provide satellite communications services, some of which will be maintained by Intelsat and some of which will be independent. This report addresses the problems of conflict in…

Apple - Indian experimental geostationary communication satellite

Science.gov (United States)

Rao, U. R.; Vasagam, R. M.

Developmental steps, responsibilities, design goals, performance characteristics, and support systems for the ISRO Ariane Passenger Payload Experiment (APPLE) experimental GEO communication satellite are described. The spacecraft underwent structural, thermal, engineering, prototype, and flight qualification tests in India before being shipped to Guyana for launch on the third Ariane test flight. APPLE carries a redundant C-band communication transponder fed by a 900 mm diam parabolic reflector. A 6 GHz uplink and 4 GHz downlink are processed through a diplexer, with the receiver employing a low noise GaAs FET amplifier. In-orbit telemetry is provided by a 4095 MHz beacon with a data rate of 64 bits/sec. Two solar panels supply 210 W of power, while an on-board Ni-Cd storage battery stores 240 Wh for the ascent and during eclipse. Teleconferencing has been successfully performed using the spacecraft link.

Automation; The New Industrial Revolution.

Science.gov (United States)

Arnstein, George E.

Automation is a word that describes the workings of computers and the innovations of automatic transfer machines in the factory. As the hallmark of the new industrial revolution, computers displace workers and create a need for new skills and retraining programs. With improved communication between industry and the educational community to…

A Study on Fuel Estimation Algorithms for a Geostationary Communication & Broadcasting Satellite

OpenAIRE

Jong Won Eun

2000-01-01

It has been developed to calculate fuel budget for a geostationary communication and broadcasting satellite. It is quite essential that the pre-launch fuel budget estimation must account for the deterministic transfer and drift orbit maneuver requirements. After on-station, the calculation of satellite lifetime should be based on the estimation of remaining fuel and assessment of actual performance. These estimations step from the proper algorithms to produce the prediction of satellite lifet...

Study of LEO-SAT microwave link for broad-band mobile satellite communication system

Science.gov (United States)

Fujise, Masayuki; Chujo, Wataru; Chiba, Isamu; Furuhama, Yoji; Kawabata, Kazuaki; Konishi, Yoshihiko

1993-01-01

In the field of mobile satellite communications, a system based on low-earth-orbit satellites (LEO-SAT's) such as the Iridium system has been proposed. The LEO-SAT system is able to offer mobile telecommunication services in high-latitude areas. Rain degradation, fading and shadowing are also expected to be decreased when the system is operated at a high elevation angle. Furthermore, the propagation delay generated in the LEO-SAT system is less pronounced than that in the geostationary orbit satellite (GEO-SAT) system and, in voice services, the effect of the delay is almost negligible. We proposed a concept of a broad-band mobile satellite communication system with LEO-SAT's and Optical ISL. In that system, a fixed L-band (1.6/1.5 GHz) multibeam is used to offer narrow band service to the mobile terminals in the entire area covered by a LEO-SAT and steerable Ka-band (30/20 GHz) spot beams are used for the wide band service. In this paper, we present results of a study of LEO-SAT microwave link between a satellite and a mobile terminal for a broad-band mobile satellite communication system. First, the results of link budget calculations are presented and the antennas mounted on satellites are shown. For a future mobile antenna technology, we also show digital beamforming (DBF) techniques. DBF, together with modulation and/or demodulation, is becoming a key technique for mobile antennas with advanced functions such as antenna pattern calibration, correction, and radio interference suppression. In this paper, efficient DBF techniques for transmitting and receiving are presented. Furthermore, an adaptive array antenna system suitable for this LEO-SAT is presented.

DOD Use of Commercial Wideband Satellite Communications Systems: How Much is Needed, and How Do We Get It?

National Research Council Canada - National Science Library

Hutchens, Robert

2001-01-01

..., A key enabler to this end is sufficient wideband satellite communications connectivity DoD's organic wideband satellite communications capabilities are inadequate, so commercial services must be used...

Intersatellite Link (ISL) application to commercial communications satellites. Volume 1: Executive summary

Science.gov (United States)

Young, S. Lee

1987-01-01

Based on a comprehensive evaluation of the fundamental Intersatellite Link (ISL) systems characteristics, potential applications of ISLs to domestic, regional, and global commercial satellite communications were identified, and their cost-effectiveness and other systems benefits quantified wherever possible. Implementation scenarios for the cost-effective communications satellite systems employing ISLs were developed for the first launch in 1993 to 1994 and widespread use of ISLs in the early 2000's. Critical technology requirements for both the microwave (60 GHz) and optical (0.85 micron) ISL implementations were identified, and their technology development programs, including schedule and cost estimates, were derived.

Networks systems and operations. [wideband communication techniques for data links with satellites

Science.gov (United States)

1975-01-01

The application of wideband communication techniques for data links with satellites is discussed. A diagram of the demand assigned voice communications system is provided. The development of prototype integrated spacecraft paramps at S- and C-bands is described and the performance of space-qualified paramps is tabulated. The characteristics of a dual parabolic cylinder monopulse zoom antenna for use with the tracking and data relay satellite system (TDRSS) are analyzed. The development of a universally applicable transponder at S-band is reported. A block diagram of the major subassemblies of the S-band transponder is included. The technology aspects of network timing and synchronization of communication systems are to show the use of the Omega navigation system. The telemetry data compression system used during the Skylab program is evaluated.

Intersatellite link application to commercial communications satellites

Science.gov (United States)

Lee, Young S.; Atia, Ali E.; Ponchak, Denise S.

1988-01-01

The fundamental characteristics of intersatellite link (ISL) systems, and their application to domestic, regional, and global satellite communications, are described. The quantitative advantages of using ISLs to improve orbit utilization, spectrum occupancy, transmission delay (compared to multi-hop links), coverage, and connectivity, and to reduce the number of earth station antennas, are also presented. Cost-effectiveness and other systems benefits of using ISLs are identified, and the technical and systems planning aspects of ISL systems implementation are addressed.

Cybersecurity threats to satellite communications: Towards a typology of state actor responses

Science.gov (United States)

Housen-Couriel, Deborah

2016-11-01

Cybersecurity threats to satellite communications are a relatively new phenomenon, yet have quickly come to the forefront of concern for the sustainability of satellite systems due to the vulnerabilities that such threats may exploit and negatively impact. These vulnerabilities are mission-critical: they include launch systems, communications, telemetry, tracking and command, and mission completion. They and other aspects of satellite communications depend heavily on secure and resilient cyber capabilities for all stages of the satellite's lifespan. Because of the inherently global nature of both satellite and cyberspace activities, these capabilities rely significantly on international cooperation for setting a baseline of agreed legal norms that protect satellites and satellite communications. This critical cooperation is relevant during all mission phases, from planning to final wrap-up. Under optimal circumstances, the norms and standards protecting satellites and satellite transmissions are developed and enforced by those nation-state actors that are committed to system operability and overall mission sustainability for those satellites launched under their aegis and responsibility. However, when breaches of international law do occur in the form of hostile cyber events that cause damage to satellite communications, a range of measures should be available to the victim state, provided by the appropriate legal regime or regimes. This article proposes that a comprehensive and integrative multi-stakeholder review be undertaken in the near future of the measures available under international law for responding to hostile acts directed at satellite systems and communications, in a manner that takes into account both existing regimes of international law reviewed herein, as well as considerations of cybersecurity. These measures will depend upon the characterization of hostile interference with satellite transmissions in accordance with a proposed typology of

The Visual Communication or Graphic Communication Dilemma

Science.gov (United States)

Fecik, John T.

1975-01-01

The author reviews the history of communication and communications technology, considers differences between "visual communication" and "graphic communication," and comments on "seeds of revolution" in the industry. He offers four components of an educational structure or organization titled "graphic…

An assessment of the status and trends in satellite communications 1986-2000: An information document prepared for the Communications Subcommittee of the Space Applications Advisory Committee

Science.gov (United States)

Poley, W. A.; Stevens, G. H.; Stevenson, S. M.; Lekan, J.; Arth, C. H.; Hollansworth, J. E.; Miller, E. F.

1986-01-01

This is a response to a Space Applications Advisory Committee (SAAC) request for information about the status and trends in satellite communications, to be used to support efforts to conceive and recommend long range goals for NASA communications activities. Included in this document are assessments of: (1) the outlook for satellite communications, including current applications, potential future applications, and impact of the changing environment such as optical fiber networks, the Integrated Services Digital Network (ISDN) standard, and the rapidly growing market for Very Small Aperture Terminals (VSAT); (2) the restrictions imposed by our limited spectrum resource; and (3) technology needs indicated by future trends. Potential future systems discussed include: large powerful satellites for providing personal communications; VSAT compatible satellites with onboard switching and having voice capability; large satellites which offer a pervasive T1 network service (primarily for video-phone); and large geostationary communications facilities which support common use by several carriers. Also, discussion is included of NASA particular needs and possible future systems. Based on the mentioned system concepts, specific technology recommendations are provided for the time frames of now - 1993, 1994 - 2000, and 2000 - 2010.

Leo Satellite Communication through a LEO Constellation using TCP/IP Over ATM

Science.gov (United States)

Foore, Lawrence R.; Konangi, Vijay K.; Wallett, Thomas M.

1999-01-01

The simulated performance characteristics for communication between a terrestrial client and a Low Earth Orbit (LEO) satellite server are presented. The client and server nodes consist of a Transmission Control Protocol /Internet Protocol (TCP/IP) over ATM configuration. The ATM cells from the client or the server are transmitted to a gateway, packaged with some header information and transferred to a commercial LEO satellite constellation. These cells are then routed through the constellation to a gateway on the globe that allows the client/server communication to take place. Unspecified Bit Rate (UBR) is specified as the quality of service (QoS). Various data rates are considered.

Taking the Politics Out of Satellite and Space-Based Communications Protocols

Science.gov (United States)

Ivancic, William D.

2006-01-01

After many years of studies, experimentation, and deployment, large amounts of misinformation and misconceptions remain regarding applicability of various communications protocols for use in satellite and space-based networks. This paper attempts to remove much of the politics, misconceptions, and misinformation that have plagued spacebased communications protocol development and deployment. This paper provides a common vocabulary for communications; a general discussion of the requirements for various communication environments; an evaluation of tradeoffs between circuit and packet-switching technologies, and the pros and cons of various link, network, transport, application, and security protocols. Included is the applicability of protocol enhancing proxies to NASA, Department of Defense (DOD), and commercial space communication systems.

Technology programs and related policies - Impacts on communications satellite business ventures

Science.gov (United States)

Greenberg, J. S.

1985-01-01

The DOMSAT II stochastic communication satellite business venture financial planning simulation model is described. The specification of business scenarios and the results of several analyses are presented. In particular, the impacts of NASA on-orbit propulsion and power technology programs are described. The effects of insurance rates and self-insurance and of the use of the Space Shuttle and Ariane transportation systems on a typical fixed satellite service business venture are discussed.

An approach to effective UHF (S/L band) data communications for satellite Personal Communication Service (PCS)

Science.gov (United States)

Hayase, Joshua Y.

1995-01-01

Reliable signaling information transfer is fundamental in supporting the needs of data communication PCS via LMS (Land Mobile Service) SSs (satellite systems). The needs of the system designer can be satisfied only through the collection of media information that can be brought to bear on the pertinent design issues. We at ISI hope to continue our dialogue with fading media experts to address the unique data communications needs of PCS via LMS SSs.

Trellis-coded CPM for satellite-based mobile communications

Science.gov (United States)

Abrishamkar, Farrokh; Biglieri, Ezio

1988-01-01

Digital transmission for satellite-based land mobile communications is discussed. To satisfy the power and bandwidth limitations imposed on such systems, a combination of trellis coding and continuous-phase modulated signals are considered. Some schemes based on this idea are presented, and their performance is analyzed by computer simulation. The results obtained show that a scheme based on directional detection and Viterbi decoding appears promising for practical applications.

Satellite communication system for emergency monitoring within the Chernobyl exclusion zone

International Nuclear Information System (INIS)

Franchini, C.; Mensa, M.; Kanevsky, V.A.

1997-01-01

A Satellite Emergency Monitoring system of the Chernobyl Exclusive Zone (SEM CEZ) was designed to provide the Ukraine authorities and the neighbouring countries with updated information when an emergency situation occurs in the Exclusion Zone. This is of particular importance when environment contamination has transboundary effect. SEM system consists of mobile and fixed sensors reporting data via a dedicated satellite communications link. Mobile sensors are fitted with Global Positioning System (GPS) receivers that determine current coordinates of the sensor. Sensors data are transmitted to the Emergency Monitoring Centre equipped with PC and a satellite terminal. Both sensors data and the current position are visualized on digital maps

Intuitive Tools for the Design and Analysis of Communication Payloads for Satellites

Science.gov (United States)

Culver, Michael R.; Soong, Christine; Warner, Joseph D.

2014-01-01

In an effort to make future communications satellite payload design more efficient and accessible, two tools were created with intuitive graphical user interfaces (GUIs). The first tool allows payload designers to graphically design their payload by using simple drag and drop of payload components onto a design area within the program. Information about each picked component is pulled from a database of common space-qualified communication components sold by commerical companies. Once a design is completed, various reports can be generated, such as the Master Equipment List. The second tool is a link budget calculator designed specifically for ease of use. Other features of this tool include being able to access a database of NASA ground based apertures for near Earth and Deep Space communication, the Tracking and Data Relay Satellite System (TDRSS) base apertures, and information about the solar system relevant to link budget calculations. The link budget tool allows for over 50 different combinations of user inputs, eliminating the need for multiple spreadsheets and the user errors associated with using them. Both of the aforementioned tools increase the productivity of space communication systems designers, and have the colloquial latitude to allow non-communication experts to design preliminary communication payloads.

Navigating the Information Revolution: Choices for Laggard Countries

National Research Council Canada - National Science Library

Gatune, Julius

2007-01-01

The rapid diffusion of information and communication technologies (ICTs) during the last two decades has had a profound impact on all spheres of human endeavors, changes that are collectively referred to as the Information Revolution (IR...

Forecast of space shuttle flight requirements for launch of commercial communications satellites

Science.gov (United States)

1977-01-01

The number of communication satellites required over the next 25 years to support domestic and regional communication systems for telephony, telegraphy and other low speed data; video teleconferencing, new data services, direct TV broadcasting; INTELSAT; and maritime and aeronautical services was estimated to determine the number of space shuttle flights necessary for orbital launching.

R and D limited partnerships (possible applications in advanced communications satellite technology experiment program)

Science.gov (United States)

1985-01-01

Typical R&D limited partnership arrangements, advantages and disadvantages of R&D limited partnership (RDLPs) and antitrust and tax implications are described. A number of typical forms of RDLPs are described that may be applicable for use in stimulating R&D and experimental programs using the advanced communications technology satellite. The ultimate goal is to increase the rate of market penetration of goods and/or services based upon advanced satellite communications technology. The conditions necessary for these RDLP forms to be advantageous are outlined.

Proportional fair scheduling algorithm based on traffic in satellite communication system

Science.gov (United States)

Pan, Cheng-Sheng; Sui, Shi-Long; Liu, Chun-ling; Shi, Yu-Xin

2018-02-01

In the satellite communication network system, in order to solve the problem of low system capacity and user fairness in multi-user access to satellite communication network in the downlink, combined with the characteristics of user data service, an algorithm study on throughput capacity and user fairness scheduling is proposed - Proportional Fairness Algorithm Based on Traffic(B-PF). The algorithm is improved on the basis of the proportional fairness algorithm in the wireless communication system, taking into account the user channel condition and caching traffic information. The user outgoing traffic is considered as the adjustment factor of the scheduling priority and presents the concept of traffic satisfaction. Firstly,the algorithm calculates the priority of the user according to the scheduling algorithm and dispatches the users with the highest priority. Secondly, when a scheduled user is the business satisfied user, the system dispatches the next priority user. The simulation results show that compared with the PF algorithm, B-PF can improve the system throughput, the business satisfaction and fairness.

Research of remote control for Chinese Antarctica Telescope based on iridium satellite communication

Science.gov (United States)

Xu, Lingzhe; Yang, Shihai

2010-07-01

Astronomers are ever dreaming of sites with best seeing on the Earth surface for celestial observation, and the Antarctica is one of a few such sites only left owing to the global air pollution. However, Antarctica region is largely unaccessible for human being due to lacking of fundamental living conditions, travel facilities and effective ways of communication. Worst of all, the popular internet source as a general way of communication scarcely exists there. Facing such a dilemma and as a solution remote control and data transmission for telescopes through iridium satellite communication has been put forward for the Chinese network Antarctic Schmidt Telescopes 3 (AST3), which is currently under all round research and development. This paper presents iridium satellite-based remote control application adapted to telescope control. The pioneer work in China involves hardware and software configuration utilizing techniques for reliable and secure communication, which is outlined in the paper too.

1st International Conference on Intelligent Computing, Communication and Devices

CERN Document Server

Patnaik, Srikanta; Ichalkaranje, Nikhil

2015-01-01

In the history of mankind, three revolutions which impact the human life are the tool-making revolution, agricultural revolution and industrial revolution. They have transformed not only the economy and civilization but the overall development of the society. Probably, intelligence revolution is the next revolution, which the society will perceive in the next 10 years. ICCD-2014 covers all dimensions of intelligent sciences, i.e. Intelligent Computing, Intelligent Communication and Intelligent Devices. This volume covers contributions from Intelligent Communication which are from the areas such as Communications and Wireless Ad Hoc & Sensor Networks, Speech & Natural Language Processing, including Signal, Image and Video Processing and Mobile broadband and Optical networks, which are the key to the ground-breaking inventions to intelligent communication technologies. Secondly, Intelligent Device is any type of equipment, instrument, or machine that has its own computing capability. Contributions from ...

Satellite Communications Industry

Science.gov (United States)

1993-04-01

Ariane $loom SAJAC 1 Hughes Satellite Japan 06/94 $150m SAJAC 2 Hughes Satellite Japan -- (spare) $150m SatcomHl GE GE Americom /95 $50m SOLIDARIDAD ...1 Hughes SCT (Mexico) 11/93 Ariane $loom SOLIDARIDAD 2 Hughes SCT (Mexico) /94 $loom Superbird Al Loral Space Com Gp (Jap) 11/92 Ariane $175m

Mechanical Design of Military Communication Satellite X-band PCM

Directory of Open Access Journals (Sweden)

Hyung Je Woo

1998-12-01

Full Text Available Before an actual military communications satellite is designed and constructed, a feasibility study should take place. The basic functions of such system can be observed and demonstrated in an X-Band payload simulator. For this purpose a Payload Concept Model (PCM for X-Band payload subsystem has been developed to simulate the workings of an actual military communications payload. This paper explains and illustrates the mechanical design, manufacture, and integration of the PCM. Basic RF tests also have been performed in order to verify the design requirement of the system. The results demonstrate successful development of the PCM and operation without RF losses.

Emerging markets for satellite data communications in the public service

Science.gov (United States)

Potter, J. G.

1978-01-01

The paper discusses some of the current and potential markets for satellite data communications as projected by the Public Service Satellite Consortium (PSSC). Organizations in the public service sector are divided into three categories, depending on their expected benefits and organizational changes due to increased satellite telecommunications use: A - modest institutional adjustments are necessary and significant productivity gains are likely; B - institutional requirements picture is promising, but more information is needed to assess benefits and risk; and C - major institutional adjustments are needed, risks are high but possible benefits are high. These criteria are applied to the U.S. health care system, continuing education, equipment maintenance, libraries, environmental monitoring, and other potential markets. The potential revenues are seen to be significant, but what is needed is a cooperative effort by common carriers and major public service institutions to aggregate the market.

Optimizing communication satellites payload configuration with exact approaches

Science.gov (United States)

Stathakis, Apostolos; Danoy, Grégoire; Bouvry, Pascal; Talbi, El-Ghazali; Morelli, Gianluigi

2015-12-01

The satellite communications market is competitive and rapidly evolving. The payload, which is in charge of applying frequency conversion and amplification to the signals received from Earth before their retransmission, is made of various components. These include reconfigurable switches that permit the re-routing of signals based on market demand or because of some hardware failure. In order to meet modern requirements, the size and the complexity of current communication payloads are increasing significantly. Consequently, the optimal payload configuration, which was previously done manually by the engineers with the use of computerized schematics, is now becoming a difficult and time consuming task. Efficient optimization techniques are therefore required to find the optimal set(s) of switch positions to optimize some operational objective(s). In order to tackle this challenging problem for the satellite industry, this work proposes two Integer Linear Programming (ILP) models. The first one is single-objective and focuses on the minimization of the length of the longest channel path, while the second one is bi-objective and additionally aims at minimizing the number of switch changes in the payload switch matrix. Experiments are conducted on a large set of instances of realistic payload sizes using the CPLEX® solver and two well-known exact multi-objective algorithms. Numerical results demonstrate the efficiency and limitations of the ILP approach on this real-world problem.

A communication protocol for mobile satellite systems affected by rain attenuation

Science.gov (United States)

Lay, Norman; Dessouky, Khaled

1992-01-01

A communication protocol is described that has been developed as part of a K/Ka-band mobile terminal breadboard system to be demonstrated through NASA's Advanced Communications Technology Satellite (ACTS) in 1993. The protocol is aimed at providing the means for enhancing link availability and continuity by supporting real-time data rate selection and changes during rain events. Particular attention is given to the system architecture; types of links, connections, and packets; the protocol procedures; and design rationales.

A new antenna concept for satellite communications

Science.gov (United States)

Skahill, G.; Ciccolella, D.

1982-01-01

A novel antenna configuration of two reflecting surfaces and a phased array is examined for application to satellite communications and shown to be superior in every respect to earlier designs for service to the continental United States from synchronous orbit. The vignetting that afflicts other two reflector optical systems is eliminated by use of a reflecting field element. The remaining aberrations, predominantly coma, are isolated in the time delay distribution at the surface of the array and can be compensated by ordinary array techniques. The optics exhibits infinite bandwidth and the frequency range is limited only by the design of the array.

Satellite-based quantum communication terminal employing state-of-the-art technology

Science.gov (United States)

Pfennigbauer, Martin; Aspelmeyer, Markus; Leeb, Walter R.; Baister, Guy; Dreischer, Thomas; Jennewein, Thomas; Neckamm, Gregor; Perdigues, Josep M.; Weinfurter, Harald; Zeilinger, Anton

2005-09-01

Feature Issue on Optical Wireless Communications (OWC) We investigate the design and the accommodation of a quantum communication transceiver in an existing classical optical communication terminal on board a satellite. Operation from a low earth orbit (LEO) platform (e.g., the International Space Station) would allow transmission of single photons and pairs of entangled photons to ground stations and hence permit quantum communication applications such as quantum cryptography on a global scale. Integration of a source generating entangled photon pairs and single-photon detection into existing optical terminal designs is feasible. Even more, major subunits of the classical terminals such as those for pointing, acquisition, and tracking as well as those providing the required electronic, thermal, and structural backbone can be adapted so as to meet the quantum communication terminal needs.

Design of an anti-Rician-fading modem for mobile satellite communication systems

Science.gov (United States)

Kojima, Toshiharu; Ishizu, Fumio; Miyake, Makoto; Murakami, Keishi; Fujino, Tadashi

1995-01-01

To design a demodulator applicable to mobile satellite communication systems using differential phase shift keying modulation, we have developed key technologies including an anti-Rician-fading demodulation scheme, an initial acquisition scheme, automatic gain control (AGC), automatic frequency control (AFC), and bit timing recovery (BTR). Using these technologies, we have developed one-chip digital signal processor (DSP) modem for mobile terminal, which is compact, of light weight, and of low power consumption. Results of performance test show that the developed DSP modem achieves good performance in terms of bit error ratio in mobile satellite communication environment, i.e., Rician fading channel. It is also shown that the initial acquisition scheme acquires received signal rapidly even if the carrier-to-noise power ratio (CNR) of the received signal is considerably low.

Inside the Digital Revolution

OpenAIRE

Brooke, H.

2016-01-01

Technology and transparency combined to create the digital revolution, which in turn has ushered in a new form of monitory democracy. Communicative abun-dance and global interconnection mean the democratic franchise can expand and deepen, but the author argues that it matters who is made transparent and for what purpose. Content and context matter. Technology and transparency can be used to strengthen democracy by opening up government to citizens, but the same tools can also be used by the s...

THE FOURTH INDUSTRIAL REVOLUTION „INDUSTRY 4.0”

Directory of Open Access Journals (Sweden)

Alin STĂNCIOIU

2017-05-01

Full Text Available The many observers estimate that in the world is at the beginning of a new industrial revolution, which it is considered the fourth revolution and it is called "Industry 4.0". The connecting many products to the internet, presence of sensors, wireless communications expansion, robot and intelligent machine development, real-time data analysis have the potential to turn the way the production is done. Connecting the physical world to the virtual world in cyber-physical systems it will have a disruptive impact on technologies, manufacturing processes and people.

Personal communications via ACTS satellite HBR transponders

Science.gov (United States)

Fang, Russell J. F.

1991-01-01

The concept of a fully meshed network of briefcase-sized terminals is presented for personal communications over Ka-band satellite transponders. In this concept, undesirable double-hop delays are avoided for voice communications. The bandwidth and power resources of the transponder are efficiently shared by users in a simple demand-assigned manner via code-division multiple access (CDMA). Voice, data, and facsimile are statistically multiplexed at each terminal. In order to minimize terminal costs, frequency-precorrected, and level-preadjusted continuous-wave tones are sent from the central network control station in each beam so that the terminals in each down-link beam can use these pilots as references for antenna acquisition and tracking, as reliable frequency sources, and as indicators of signal fade for up-link power control (ULPC). The potential CDMA 'near-far' problem due to up-link fades is mitigated by using ULPC. Quasi-burst mode transmission is employed to minimize the potential clock and pseudorandom number code synchronization.

Evaluation of spacecraft technology programs (effects on communication satellite business ventures), volume 2

Science.gov (United States)

Greenburg, J. S.; Kaplan, M.; Fishman, J.; Hopkins, C.

1985-01-01

The computational procedures used in the evaluation of spacecraft technology programs that impact upon commercial communication satellite operations are discussed. Computer programs and data bases are described.

NASA satellite communications application research. Phase 2: Efficient high power, solid state amplifier for EFH communications

Science.gov (United States)

Benet, James

1993-01-01

The final report describes the work performed from 9 Jun. 1992 to 31 Jul. 1993 on the NASA Satellite Communications Application Research (SCAR) Phase 2 program, Efficient High Power, Solid State Amplifier for EHF Communications. The purpose of the program was to demonstrate the feasibility of high-efficiency, high-power, EHF solid state amplifiers that are smaller, lighter, more efficient, and less costly than existing traveling wave tube (TWT) amplifiers by combining the output power from up to several hundred solid state amplifiers using a unique orthomode spatial power combiner (OSPC).

78 FR 19172 - Earth Stations Aboard Aircraft Communicating with Fixed-Satellite Service Geostationary-Orbit...

Science.gov (United States)

2013-03-29

... FEDERAL COMMUNICATIONS COMMISSION 47 CFR Parts 2 and 25 [IB Docket No. 12-376; FCC 12-161] Earth Stations Aboard Aircraft Communicating with Fixed-Satellite Service Geostationary-Orbit Space Stations... the Federal Register of March 8, 2013. The document proposed rules for Earth Stations Aboard Aircraft...

Interim Service ISDN Satellite (ISIS) simulator development for advanced satellite designs and experiments

Science.gov (United States)

Pepin, Gerard R.

1992-01-01

The simulation development associated with the network models of both the Interim Service Integrated Services Digital Network (ISDN) Satellite (ISIS) and the Full Service ISDN Satellite (FSIS) architectures is documented. The ISIS Network Model design represents satellite systems like the Advanced Communications Technology Satellite (ACTS) orbiting switch. The FSIS architecture, the ultimate aim of this element of the Satellite Communications Applications Research (SCAR) Program, moves all control and switching functions on-board the next generation ISDN communications satellite. The technical and operational parameters for the advanced ISDN communications satellite design will be obtained from the simulation of ISIS and FSIS engineering software models for their major subsystems. Discrete event simulation experiments will be performed with these models using various traffic scenarios, design parameters, and operational procedures. The data from these simulations will be used to determine the engineering parameters for the advanced ISDN communications satellite.

Exploring the boundaries of quantum mechanics: advances in satellite quantum communications.

Science.gov (United States)

Agnesi, Costantino; Vedovato, Francesco; Schiavon, Matteo; Dequal, Daniele; Calderaro, Luca; Tomasin, Marco; Marangon, Davide G; Stanco, Andrea; Luceri, Vincenza; Bianco, Giuseppe; Vallone, Giuseppe; Villoresi, Paolo

2018-07-13

Recent interest in quantum communications has stimulated great technological progress in satellite quantum technologies. These advances have rendered the aforesaid technologies mature enough to support the realization of experiments that test the foundations of quantum theory at unprecedented scales and in the unexplored space environment. Such experiments, in fact, could explore the boundaries of quantum theory and may provide new insights to investigate phenomena where gravity affects quantum objects. Here, we review recent results in satellite quantum communications and discuss possible phenomena that could be observable with current technologies. Furthermore, stressing the fact that space represents an incredible resource to realize new experiments aimed at highlighting some physical effects, we challenge the community to propose new experiments that unveil the interplay between quantum mechanics and gravity that could be realizable in the near future.This article is part of a discussion meeting issue 'Foundations of quantum mechanics and their impact on contemporary society'. © 2018 The Author(s).

The 30/20 GHz experimental communications satellite system

Science.gov (United States)

Sivo, J. N.

NASA is continuing to pursue an agressive satellite communications technology development program focused on the 30/20 GHz frequency band. A review of the program progress to date is presented. Included is a discussion of the technology program status as well as a description of the experimental system concept under study. Expected system performance characteristics together with spacecraft and payload configuration details including weight and power budget is presented. Overall program schedules of both the technology development and the flight system development are included.

Communications satellite business ventures - Measuring the impact of technology programmes and related policies

Science.gov (United States)

Greenberg, J. S.

1986-01-01

An economic evaluation and planning procedure which assesses the effects of various policies on fixed satellite business ventures is described. The procedure is based on a stochastic financial simulation model, the Domsat II, which evaluates spacecraft reliability, market performance, and cost uncertainties. The application of the Domsat II model to the assessment of NASA's ion thrusters for on-orbit propulsion and GaAs solar cell technology is discussed. The effects of insurance rates and the self-insurance option on the financial performance of communication satellite business ventures are investigated. The selection of a transportation system for placing the satellites into GEO is analyzed.

Issues for the integration of satellite and terrestrial cellular networks for mobile communications

Science.gov (United States)

Delre, Enrico; Mistretta, Ignazio; Dellipriscoli, Francesco; Settimo, Franco

1991-01-01

Satellite and terrestrial cellular systems naturally complement each other for land mobile communications, even though present systems have been developed independently. The main advantages of the integrated system are a faster wide area coverage, a better management of overloading traffic conditions, an extension to geographical areas not covered by the terrestrial network and, in perspective, the provision of only one integrated system for all mobile communications (land, aeronautical, and maritime). To achieve these goals, as far as possible the same protocols of the terrestrial network should be used also for the satellite network. Discussed here are the main issues arising from the requirements of the main integrated system. Some results are illustrated, and possible future improvements due to technical solutions are presented.

R&D of a Next Generation LEO System for Global Multimedia Mobile Satellite Communications

Science.gov (United States)

Morikawa, E.; Motoyoshi, S.; Koyama, Y.; Suzuki, R.; Yasuda, Y.

2002-01-01

Next-generation LEO System Research Center (NeLS) was formed in the end of 1997 as a research group under the Telecommunications Advancement Organization of Japan, in cooperation with the telecommunications operators, manufacturers, universities and governmental research organization. The aim of this project is to develop new technology for global multimedia mobile satellite communications services with a user data rate around 2Mbps for handy terminals. component of the IMT-2000, and the second generation of the big-LEO systems. In prosecuting this project, two-phase approach, phase 1 and phase 2, is considered. Phase 1 is the system definition and development of key technologies. In Phase 2, we plan to verify the developed technology in Phase 1 on space. From this year we shifted the stage to Phase 2, and are now developing the prototype of on-board communication systems for flight tests, which will be planed at around 2006. The satellite altitude is assumed to be 1200 km in order to reduce the number of satellites, to avoid the Van Allen radiation belts and to increase the minimum elevation angle. Ten of the circular orbits with 55 degree of inclination are selected to cover the earth surface from -70 to 70 degree in latitude. 12 satellites are positioned at regular intervals in each orbit. In this case, the minimum elevation angle from the user terminal can be keep more than 20 degree for the visibility of the satellite, and 15 degree for simultaneous visibility of two satellites. Then, NeLS Research Center was focusing on the development of key technologies as the phase 1 project. Four kinds of key technologies; DBF satellite antenna, optical inter-satellite link system, satellite network technology with on-board ATM switch and variable rate modulation were selected. Satellite Antenna Technology: Development of on-board direct radiating active phased array antenna with digital beam forming technology would be one of the most important breakthroughs for the

Was there an ‘Industrious Revolution' before the Industrial Revolution?

DEFF Research Database (Denmark)

Allen, Robert C.; Weisdorf, Jacob Louis

It is conventionally assumed that the pre-modern working year was fixed and that consumption varied with changes in wages and prices. This is challenged by the twin theories of the ‘industrious' revolution and the consumer revolution, positing a longer working year as people earned surplus money...... estimates of the actual working year, we find two ‘industrious' revolutions among rural workers; both, however, are attributable to economic hardship, and we detect no signs of a consumer revolution. For urban labourers, by contrast, a growing gap between their actual working year and the work  required...... to buy the basket provides great scope for a consumer revolution....

More About Lens Antenna For Mobile/Satellite Communication

Science.gov (United States)

Rahmat-Samii, Y.; Bodnar, D. G.; Rainer, B. K.

1990-01-01

Report presents additional details of design of proposed phased-array antenna described in "Lens Antenna for Mobile/Satellite Communication" (NPO-16948). Intended to be compact and to lie flat on top of vehicle on ground. Transmits and receives circularly polarized radiation in frequency ranges of 821 to 825 MHz and 860 to 870 MHz. Transmitting and receiving beams electronically steerable to any of 48 evenly spaced directions to provide complete azimuth coverage, and would be fixed, but wide, in elevation, to provide coverage at elevation angles from 20 degrees to 60 degrees.

Dialing long distance : communications to northern operations like the MGP require sophisticated satellite networks for voice, data

Energy Technology Data Exchange (ETDEWEB)

Cook, D.

2006-04-15

Telecommunications will play a major role in the construction of the Mackenzie Gas Project due to the remoteness of its location and the volume of communication data required to support the number of people involved and the amount of construction activity. While suppliers for communications tools have not yet been identified, initial telecommunications plans call for the installation of communication equipment at all camps, major facility sites and construction locations. Equipment will be housed in self-contained, climate-controlled buildings called telecommunication service modules (TSMs), which will be connected to each other as well as to existing public communications networks. The infrastructure will support telephone and fax systems; Internet and electronic mail services; multiple channel very high frequency radios; air-to-ground communication at airstrips and helipads; ship-to-shore at barge landings; closed circuit television; satellite community antenna television; CBC radio broadcast; public address systems; security systems; and supervisory control and data acquisition (SCADA) systems. An Internet Protocol (IP) network with a voice telephone system will be implemented along with a geostationary orbit satellite network. Satellite servers and real-time data services will be used. Car kits that allow call and battery-operated self-contained telemetry devices designed to communicate via a satellite system have been commissioned for the project that are capable of providing cost-efficient and reliable asset tracking and fleet management in remote regions and assisting in deployment requirements. It was concluded that many of today's mega-projects are the driving factors behind new telecommunications solutions in remote areas. 1 fig.

A Mobile Communications Space Link Between the Space Shuttle Orbiter and the Advanced Communications Technology Satellite

Science.gov (United States)

Fink, Patrick; Arndt, G. D.; Bondyopadhyay, P.; Shaw, Roland

1994-01-01

A communications experiment is described as a link between the Space Shuttle Orbiter (SSO) and the Advanced Communications Technology Satellite (ACTS). Breadboarding for this experiment has led to two items with potential for commercial application: a 1-Watt Ka-band amplifier and a Ka-band, circularly polarized microstrip antenna. Results of the hybrid Ka-band amplifier show gain at 30 dB and a saturated output power of 28.5 dBm. A second version comprised of MMIC amplifiers is discussed. Test results of the microstrip antenna subarray show a gain of approximately 13 dB and excellent circular polarization.

The Media and the Making of the 2011 Egyptian Revolution

Directory of Open Access Journals (Sweden)

Amr Osman

2012-05-01

Full Text Available While views may differ on the factors that made the 2011 Egyptian revolution possible, the role of mass media will remain undisputable. The Internet-based social networks caught the Mubarak regime by surprise, and the popular disillusionment with the ‘national’ media led the public to turn to private newspapers and satellite channels for keeping pace with the events. This paper examines the role of specific media during the 18 days of the 2011 Egyptian revolution – from 25 January to 11 February, 2011 – which we have divided into four parts. It discusses how these media contributed to the unfolding of events, conceptualized the protests and the demands of the public, and presented the actors that participated in or opposed the revolution. These points are addressed by discussing the content of the Facebook pages of the Sixth of April Movement and We Are All Khalid Said, as well as that of a private Egyptian newspaper, al-Shuruq, and the state-run newspaper al-Ahram.

The Iranian Revolution: The Multiple Contexts of the Iranian Revolution

NARCIS (Netherlands)

Amineh, M.P.; Eisenstadt, S.N.

2007-01-01

The Iranian Islamic Revolution, the only continual regime constituted by a modern fundamentalist movement, shares many of the characteristics of the Great revolutions. The causes of the Iranian Revolution are indeed very similar to those of the classical ones—namely the breakdown of a modernizing

Equalization and detection for digital communication over nonlinear bandlimited satellite communication channels. Ph.D. Thesis

Science.gov (United States)

Gutierrez, Alberto, Jr.

1995-01-01

This dissertation evaluates receiver-based methods for mitigating the effects due to nonlinear bandlimited signal distortion present in high data rate satellite channels. The effects of the nonlinear bandlimited distortion is illustrated for digitally modulated signals. A lucid development of the low-pass Volterra discrete time model for a nonlinear communication channel is presented. In addition, finite-state machine models are explicitly developed for a nonlinear bandlimited satellite channel. A nonlinear fixed equalizer based on Volterra series has previously been studied for compensation of noiseless signal distortion due to a nonlinear satellite channel. This dissertation studies adaptive Volterra equalizers on a downlink-limited nonlinear bandlimited satellite channel. We employ as figure of merits performance in the mean-square error and probability of error senses. In addition, a receiver consisting of a fractionally-spaced equalizer (FSE) followed by a Volterra equalizer (FSE-Volterra) is found to give improvement beyond that gained by the Volterra equalizer. Significant probability of error performance improvement is found for multilevel modulation schemes. Also, it is found that probability of error improvement is more significant for modulation schemes, constant amplitude and multilevel, which require higher signal to noise ratios (i.e., higher modulation orders) for reliable operation. The maximum likelihood sequence detection (MLSD) receiver for a nonlinear satellite channel, a bank of matched filters followed by a Viterbi detector, serves as a probability of error lower bound for the Volterra and FSE-Volterra equalizers. However, this receiver has not been evaluated for a specific satellite channel. In this work, an MLSD receiver is evaluated for a specific downlink-limited satellite channel. Because of the bank of matched filters, the MLSD receiver may be high in complexity. Consequently, the probability of error performance of a more practical

Transcending behaviorism in communication education.

Science.gov (United States)

Hartrick, G

1999-01-01

During the past decade, nursing education has been engaged in a curriculum revolution. Although this ongoing revolution has led to profound changes in nursing curricula, one area that requires further scrutiny is communication education. This article addresses the limitations of behavioral communication curricula and suggests a pedagogical process responsive to the complexity of human caring relationships and the intricacies of relational practice. The discussion includes a description of a nursing communication course developed according to the principles of transformational learning theory.

NASA satellite communications application research, phase 2 addendum. Efficient high power, solid state amplifier for EHF communications

Science.gov (United States)

Benet, James

1994-01-01

This document is an addendum to the NASA Satellite Communications Application Research (SCAR) Phase 2 Final Report, 'Efficient High Power, Solid State Amplifier for EHF Communications.' This report describes the work performed from 1 August 1993 to 11 March 1994, under contract number NASW-4513. During this reporting period an array of transistor amplifiers was repaired by replacing all MMIC amplifier chips. The amplifier array was then tested using three different feedhorn configurations. Descriptions, procedures, and results of this testing are presented in this report, and conclusions are drawn based on the test results obtained.

Attitude Control Subsystem for the Advanced Communications Technology Satellite

Science.gov (United States)

Hewston, Alan W.; Mitchell, Kent A.; Sawicki, Jerzy T.

1996-01-01

This paper provides an overview of the on-orbit operation of the Attitude Control Subsystem (ACS) for the Advanced Communications Technology Satellite (ACTS). The three ACTS control axes are defined, including the means for sensing attitude and determining the pointing errors. The desired pointing requirements for various modes of control as well as the disturbance torques that oppose the control are identified. Finally, the hardware actuators and control loops utilized to reduce the attitude error are described.

The impact of customer-contractor interactions on spacecraft innovation: Insights from communication satellite history

Science.gov (United States)

Szajnfarber, Zoe; Stringfellow, Margaret V.; Weigel, Annalisa L.

2010-11-01

This paper captures a first detailed attempt to quantitatively analyze the innovation history of the space sector. Building on a communication satellite innovation metric and a spacecraft innovation framework developed as part of an ongoing project, this paper presents a preliminary model of global communication satellite innovation. In addition to innovation being a function of the rate of performance normalized by price, innovation was found to be strongly influenced by characteristics of the customer-contractor contractual relationship. Specifically, Department of Defense contracts tend to result in a lower level of innovation on average as compared to other customers. Also, particular customer-contractor pairs perform differently and exhibit a second order relationship in time.

Mitigating Aviation Communication and Satellite Orbit Operations Surprises from Adverse Space Weather

Science.gov (United States)

Tobiska, W. Kent

2008-01-01

Adverse space weather affects operational activities in aviation and satellite systems. For example, large solar flares create highly variable enhanced neutral atmosphere and ionosphere electron density regions. These regions impact aviation communication frequencies as well as precision orbit determination. The natural space environment, with its dynamic space weather variability, is additionally changed by human activity. The increase in orbital debris in low Earth orbit (LEO), combined with lower atmosphere CO2 that rises into the lower thermosphere and causes increased cooling that results in increased debris lifetime, adds to the environmental hazards of navigating in near-Earth space. This is at a time when commercial space endeavors are posed to begin more missions to LEO during the rise of the solar activity cycle toward the next maximum (2012). For satellite and aviation operators, adverse space weather results in greater expenses for orbit management, more communication outages or aviation and ground-based high frequency radio used, and an inability to effectively plan missions or service customers with space-based communication, imagery, and data transferal during time-critical activities. Examples of some revenue-impacting conditions and solutions for mitigating adverse space weather are offered.

The Future of Satellite Communications Technology.

Science.gov (United States)

Nowland, Wayne

1985-01-01

Discusses technical advances in satellite technology since the 1960s, and the International Telecommunications Satellite Organization's role in these developments; describes how AUSSAT, Australia's domestic satellite system, exemplifies the latest developments in satellite technology; and reviews satellite system features, possible future…

Integrating small satellite communication in an autonomous vehicle network: A case for oceanography

Science.gov (United States)

Guerra, André G. C.; Ferreira, António Sérgio; Costa, Maria; Nodar-López, Diego; Aguado Agelet, Fernando

2018-04-01

Small satellites and autonomous vehicles have greatly evolved in the last few decades. Hundreds of small satellites have been launched with increasing functionalities, in the last few years. Likewise, numerous autonomous vehicles have been built, with decreasing costs and form-factor payloads. Here we focus on combining these two multifaceted assets in an incremental way, with an ultimate goal of alleviating the logistical expenses in remote oceanographic operations. The first goal is to create a highly reliable and constantly available communication link for a network of autonomous vehicles, taking advantage of the small satellite lower cost, with respect to conventional spacecraft, and its higher flexibility. We have developed a test platform as a proving ground for this network, by integrating a satellite software defined radio on an unmanned air vehicle, creating a system of systems, and several tests have been run successfully, over land. As soon as the satellite is fully operational, we will start to move towards a cooperative network of autonomous vehicles and small satellites, with application in maritime operations, both in-situ and remote sensing.

A description of QUALCOMM Automatic Satellite Position Reporting (QASPR(R)) for mobile communications

Science.gov (United States)

Ames, William G.

1990-01-01

Two satellite position reporting has been introduced into the OmniTRACS mobile satellite communication system. This system significantly improves position reporting reliability and accuracy while simplifying the terminal's hardware. The positioning technique uses the original OmniTRACS TDMA timing signal formats in the forward and return link directions plus an auxiliary, low power forward link signal through a second satellite to derive distance values. The distances are then converted into the mobile terminal's latitude and longitude in real time. A minor augmentation of the spread spectrum profile of the return link allowed the resolution of periodic ambiguities. The system also locates the two satellites in real time with fixed platforms in known locations using identical mobile terminal hardware. Initial accuracies of 1/4 mile have been realized uniformly throughout the USA using a satellite separation of 22 degrees and there are no dead zones, skywaves, or cycle slips as found in terrestrial systems like LORAN-C.

Study on networking issues of medium earth orbit satellite communications systems

Science.gov (United States)

Araki, Noriyuki; Shinonaga, Hideyuki; Ito, Yasuhiko

1993-01-01

Two networking issues of communications systems with medium earth orbit (MEO) satellites, namely network architectures and location determination and registration methods for hand-held terminals, are investigated in this paper. For network architecture, five candidate architectures are considered and evaluated in terms of signaling traffic. For location determination and registration, two methods are discussed and evaluated.

Optical intersatellite links - Application to commercial satellite communications

Science.gov (United States)

Paul, D.; Faris, F.; Garlow, R.; Inukai, T.; Pontano, B.; Razdan, R.; Ganz, Aura; Caudill, L.

1992-01-01

Application of optical intersatellite links for commercial satellite communications services is addressed in this paper. The feasibility of commercialization centers around basic issues such as the need and derived benefits, implementation complexity and overall cost. In this paper, commercialization of optical ISLs is assessed in terms of the services provided, systems requirements and feasibility of appropriate technology. Both long- and short-range ISLs for GEO-GEO, GEO-LEO and LEO applications are considered. Impact of systems requirements on the payload design and use of advanced technology in reducing its mass, power, and volume requirements are discussed.

Quantum communication for satellite-to-ground networks with partially entangled states

International Nuclear Information System (INIS)

Chen Na; Quan Dong-Xiao; Pei Chang-Xing; Yang-Hong

2015-01-01

To realize practical wide-area quantum communication, a satellite-to-ground network with partially entangled states is developed in this paper. For efficiency and security reasons, the existing method of quantum communication in distributed wireless quantum networks with partially entangled states cannot be applied directly to the proposed quantum network. Based on this point, an efficient and secure quantum communication scheme with partially entangled states is presented. In our scheme, the source node performs teleportation only after an end-to-end entangled state has been established by entanglement swapping with partially entangled states. Thus, the security of quantum communication is guaranteed. The destination node recovers the transmitted quantum bit with the help of an auxiliary quantum bit and specially defined unitary matrices. Detailed calculations and simulation analyses show that the probability of successfully transferring a quantum bit in the presented scheme is high. In addition, the auxiliary quantum bit provides a heralded mechanism for successful communication. Based on the critical components that are presented in this article an efficient, secure, and practical wide-area quantum communication can be achieved. (paper)

Millimeter wave propagation modeling of inhomogeneous rain media for satellite communications systems

Science.gov (United States)

Persinger, R. R.; Stutzman, W. L.

1978-01-01

A theoretical propagation model that represents the scattering properties of an inhomogeneous rain often found on a satellite communications link is presented. The model includes the scattering effects of an arbitrary distribution of particle type (rain or ice), particle shape, particle size, and particle orientation within a given rain cell. An associated rain propagation prediction program predicts attenuation, isolation and phase shift as a function of ground rain rate. A frequency independent synthetic storm algorithm is presented that models nonuniform rain rates present on a satellite link. Antenna effects are included along with a discussion of rain reciprocity. The model is verified using the latest available multiple frequency data from the CTS and COMSTAR satellites. The data covers a wide range of frequencies, elevation angles, and ground site locations.

Economics of satellite communications systems

Science.gov (United States)

Pritchard, Wilbur L.

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

Communication and Control in the Canadian North: The Role of Interactive Satellites.

Science.gov (United States)

Valaskakis, Gail G.

In 1972 the Canadian government launched its first domestic communications satellite, Anik A, which relays direct broadcast television and telephone messages to northern communities. The impact of television on Inuit life has raised issues and concerns pertaining to native language broadcasting, media access and control, and cultural identity…

Optimization of Joint Power and Bandwidth Allocation in Multi-Spot-Beam Satellite Communication Systems

Directory of Open Access Journals (Sweden)

Heng Wang

2014-01-01

Full Text Available Multi-spot-beam technique has been widely applied in modern satellite communication systems. However, the satellite power and bandwidth resources in a multi-spot-beam satellite communication system are scarce and expensive; it is urgent to utilize the resources efficiently. To this end, dynamically allocating the power and bandwidth is an available way. This paper initially formulates the problem of resource joint allocation as a convex optimization problem, taking into account a compromise between the maximum total system capacity and the fairness among the spot beams. A joint bandwidth and power allocation iterative algorithm based on duality theory is then proposed to obtain the optimal solution of this optimization problem. Compared with the existing separate bandwidth or power optimal allocation algorithms, it is shown that the joint allocation algorithm improves both the total system capacity and the fairness among spot beams. Moreover, it is easy to be implemented in practice, as the computational complexity of the proposed algorithm is linear with the number of spot beams.

Mass and power modeling of communication satellites

Science.gov (United States)

Price, Kent M.; Pidgeon, David; Tsao, Alex

1991-01-01

Analytic estimating relationships for the mass and power requirements for major satellite subsystems are described. The model for each subsystem is keyed to the performance drivers and system requirements that influence their selection and use. Guidelines are also given for choosing among alternative technologies which accounts for other significant variables such as cost, risk, schedule, operations, heritage, and life requirements. These models are intended for application to first order systems analyses, where resources do not warrant detailed development of a communications system scenario. Given this ground rule, the models are simplified to 'smoothed' representation of reality. Therefore, the user is cautioned that cost, schedule, and risk may be significantly impacted where interpolations are sufficiently different from existing hardware as to warrant development of new devices.

Defense Science Board Task Force on Military Satellite Communication and Tactical Networking. Executive Summary

Science.gov (United States)

2017-03-01

Interface Processor BCT Brigade Combat Team BFT Blue Force Tracking BLOS Beyond Line-of-Sight C2 Command And Control C2E Communications in...Satellite Communications and Tactical Networking Appendix D-2 GIG Global Information Grid GMR Ground Mobile Radio GPS Global Positioning System...System SIPRNet Secret Internet Protocol Router Network SITREPS Situational Reports SMART -T Secure Mobile Anti-Jam Reliable Tactical Terminal SMC Space

The Computer Revolution.

Science.gov (United States)

Berkeley, Edmund C.

"The Computer Revolution", a part of the "Second Industrial Revolution", is examined with reference to the social consequences of computers. The subject is introduced in an opening section which discusses the revolution in the handling of information and the history, powers, uses, and working s of computers. A second section examines in detail the…

Prediction of Communication Outage Period between Satellite and Earth station Due to Sun Interference

Directory of Open Access Journals (Sweden)

Yongjun Song

2010-03-01

Full Text Available We developed a computer program to predict solar interference period. To calculate Sun‘s position, we used DE406 ephemerides and Earth ellipsoid model. The Sun‘s position error is smaller than 10arcsec. For the verification of the calculation, we used TU media ground station on Seongsu-dong, and MBSAT geostationary communication satellite. We analysis errors, due to satellite perturbation and antenna align. The time error due to antenna align has -35 to +16 seconds at 0.1 degree, and -27 to +41 seconds at 0.25 degree. The time errors derived by satellite perturbation has 30 to 60 seconds.

Intersatellite Link (ISL) application to commercial communications satellites. Volume 2: Technical final report

Science.gov (United States)

Young, S. Lee

1987-01-01

Intersatellite Link (ISL) applications can improve and expand communication satellite services in a number of ways. As the demand for orbital slots within prime regions of the geostationary arc increases, attention is being focused on ISLs as a method to utilize this resource more efficiently and circumvent saturation. Various GEO-to-GEO applications were determined that provide potential benefits over existing communication systems. A set of criteria was developed to assess the potential applications. Intersatellite link models, network system architectures, and payload configurations were developed. For each of the chosen ISL applications, ISL versus non-ISL satellite systems architectures were derived. Both microwave and optical ISL implementation approaches were evaluated for payload sizing and cost analysis. The technological availability for ISL implementations was assessed. Critical subsystems technology areas were identified, and an estamate of the schedule and cost to advance the technology to the requiered state of readiness was made.

Why is CDMA the solution for mobile satellite communication

Science.gov (United States)

Gilhousen, Klein S.; Jacobs, Irwin M.; Padovani, Roberto; Weaver, Lindsay A.

1989-01-01

It is demonstrated that spread spectrum Code Division Multiple Access (CDMA) systems provide an economically superior solution to satellite mobile communications by increasing the system maximum capacity with respect to single channel per carrier Frequency Division Multiple Access (FDMA) systems. Following the comparative analysis of CDMA and FDMA systems, the design of a model that was developed to test the feasibility of the approach and the performance of a spread spectrum system in a mobile environment. Results of extensive computer simulations as well as laboratory and field tests results are presented.

Effect of digital scrambling on satellite communication links

Science.gov (United States)

Dessouky, K.

1985-01-01

Digital data scrambling has been considered for communication systems using NRZ symbol formats. The purpose is to increase the number of transitions in the data to improve the performance of the symbol synchronizer. This is accomplished without expanding the bandwidth but at the expense of increasing the data bit error rate (BER). Models for the scramblers/descramblers of practical interest are presented together with the appropriate link model. The effects of scrambling on the performance of coded and uncoded links are studied. The results are illustrated by application to the Tracking and Data Relay Satellite System (TDRSS) links. Conclusions regarding the usefulness of scrambling are also given.

CubeSat quantum communications mission

Energy Technology Data Exchange (ETDEWEB)

Oi, Daniel K.L. [University of Strathclyde, SUPA Department of Physics, Glasgow (United Kingdom); University of Strathclyde, Strathclyde Space Institute, Glasgow (United Kingdom); Ling, Alex [National University of Singapore, Centre for Quantum Technologies, Singapore (Singapore); National University of Singapore, Dept. of Physics, Singapore (Singapore); Vallone, Giuseppe; Villoresi, Paolo [Universita degli Studi di Padova, Dipartimento di Ingegneria dell' Informazione, Padova (Italy); Greenland, Steve; Kerr, Emma [University of Strathclyde, Advanced Space Concepts Laboratory, Mechanical and Aerospace Engineering, Glasgow (United Kingdom); Macdonald, Malcolm [Technology and Innovation Centre, Scottish Centre of Excellence in Satellite Applications, Glasgow (United Kingdom); Weinfurter, Harald [Ludwig-Maximilians-Universitaet, Department fuer Physik, Munich (Germany); Kuiper, Hans [Delft University of Technology, Space Systems Engineering, Aerospace Engineering, Delft (Netherlands); Charbon, Edoardo [AQUA, EPFL, Lausanne (Switzerland); Delft University of Technology, Delft (Netherlands); Ursin, Rupert [Vienna Austrian Academy of Sciences, Institute for Quantum Optics and Quantum Information, Vienna (Austria)

2017-12-15

Quantum communication is a prime space technology application and offers near-term possibilities for long-distance quantum key distribution (QKD) and experimental tests of quantum entanglement. However, there exists considerable developmental risks and subsequent costs and time required to raise the technological readiness level of terrestrial quantum technologies and to adapt them for space operations. The small-space revolution is a promising route by which synergistic advances in miniaturization of both satellite systems and quantum technologies can be combined to leap-frog conventional space systems development. Here, we outline a recent proposal to perform orbit-to-ground transmission of entanglement and QKD using a CubeSat platform deployed from the International Space Station (ISS). This ambitious mission exploits advances in nanosatellite attitude determination and control systems (ADCS), miniaturised target acquisition and tracking sensors, compact and robust sources of single and entangled photons, and high-speed classical communications systems, all to be incorporated within a 10 kg 6 litre mass-volume envelope. The CubeSat Quantum Communications Mission (CQuCoM) would be a pathfinder for advanced nanosatellite payloads and operations, and would establish the basis for a constellation of low-Earth orbit trusted-nodes for QKD service provision. (orig.)

CubeSat quantum communications mission

International Nuclear Information System (INIS)

Oi, Daniel K.L.; Ling, Alex; Vallone, Giuseppe; Villoresi, Paolo; Greenland, Steve; Kerr, Emma; Macdonald, Malcolm; Weinfurter, Harald; Kuiper, Hans; Charbon, Edoardo; Ursin, Rupert

2017-01-01

Quantum communication is a prime space technology application and offers near-term possibilities for long-distance quantum key distribution (QKD) and experimental tests of quantum entanglement. However, there exists considerable developmental risks and subsequent costs and time required to raise the technological readiness level of terrestrial quantum technologies and to adapt them for space operations. The small-space revolution is a promising route by which synergistic advances in miniaturization of both satellite systems and quantum technologies can be combined to leap-frog conventional space systems development. Here, we outline a recent proposal to perform orbit-to-ground transmission of entanglement and QKD using a CubeSat platform deployed from the International Space Station (ISS). This ambitious mission exploits advances in nanosatellite attitude determination and control systems (ADCS), miniaturised target acquisition and tracking sensors, compact and robust sources of single and entangled photons, and high-speed classical communications systems, all to be incorporated within a 10 kg 6 litre mass-volume envelope. The CubeSat Quantum Communications Mission (CQuCoM) would be a pathfinder for advanced nanosatellite payloads and operations, and would establish the basis for a constellation of low-Earth orbit trusted-nodes for QKD service provision. (orig.)

Radiation-hard mid-power booster optical fiber amplifiers for high-speed digital and analogue satellite laser communication links

Science.gov (United States)

Stampoulidis, L.; Kehayas, E.; Stevens, G.; Henwood-Moroney, L.; Hosking, P.; Robertson, A.

2017-11-01

Optical laser communications (OLC) has been identified as the technology to enable high-data rate, secure links between and within satellites, as well as between satellites and ground stations with decreased mass, size, and electrical power compared to traditional RF technology.

Interim Service ISDN Satellite (ISIS) network model for advanced satellite designs and experiments

Science.gov (United States)

Pepin, Gerard R.; Hager, E. Paul

1991-01-01

The Interim Service Integrated Services Digital Network (ISDN) Satellite (ISIS) Network Model for Advanced Satellite Designs and Experiments describes a model suitable for discrete event simulations. A top-down model design uses the Advanced Communications Technology Satellite (ACTS) as its basis. The ISDN modeling abstractions are added to permit the determination and performance for the NASA Satellite Communications Research (SCAR) Program.

47 CFR 25.279 - Inter-satellite service.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Inter-satellite service. 25.279 Section 25.279 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Operations § 25.279 Inter-satellite service. (a) Any satellite communicating with other space...

Communications satellites in the national and global health care information infrastructure: their role, impact, and issues

Science.gov (United States)

Zuzek, J. E.; Bhasin, K. B.

1996-01-01

Health care services delivered from a distance, known collectively as telemedicine, are being increasingly demonstrated on various transmission media. Telemedicine activities have included diagnosis by a doctor at a remote location, emergency and disaster medical assistance, medical education, and medical informatics. The ability of communications satellites to offer communication channels and bandwidth on demand, connectivity to mobile, remote and under served regions, and global access will afford them a critical role for telemedicine applications within the National and Global Information Infrastructure (NII/GII). The importance that communications satellites will have in telemedicine applications within the NII/GII the differences in requirements for NII vs. GII, the major issues such as interoperability, confidentiality, quality, availability, and costs, and preliminary conclusions for future usability based on the review of several recent trails at national and global levels are presented.

Sexual revolutions

NARCIS (Netherlands)

Hekma, G.; Giami, A.

2014-01-01

The sexual revolution of 1960-1980 created a major break in attitudes and practices in Western societies. It created many new freedoms for gay men, youth and women, in terms of sexual imagery, information, and rights. Leftists denounced the revolution's consumerism whilst feminists lamented its

The Advanced Communication Technology Satellite and ISDN

Science.gov (United States)

Lowry, Peter A.

1996-01-01

This paper depicts the Advanced Communication Technology Satellite (ACTS) system as a global central office switch. The ground portion of the system is the collection of earth stations or T1-VSAT's (T1 very small aperture terminals). The control software for the T1-VSAT's resides in a single CPU. The software consists of two modules, the modem manager and the call manager. The modem manager (MM) controls the RF modem portion of the T1-VSAT. It processes the orderwires from the satellite or from signaling generated by the call manager (CM). The CM controls the Recom Laboratories MSPs by receiving signaling messages from the stacked MSP shelves ro units and sending appropriate setup commands to them. There are two methods used to setup and process calls in the CM; first by dialing up a circuit using a standard telephone handset or, secondly by using an external processor connected to the CPU's second COM port, by sending and receiving signaling orderwires. It is the use of the external processor which permits the ISDN (Integrated Services Digital Network) Signaling Processor to implement ISDN calls. In August 1993, the initial testing of the ISDN Signaling Processor was carried out at ACTS System Test at Lockheed Marietta, Princeton, NJ using the spacecraft in its test configuration on the ground.

Towards a new energy revolution?; Vers une nouvelle revolution energetique?

Energy Technology Data Exchange (ETDEWEB)

Rabourbin, Sabine

2011-09-22

At the time of the 19. century's 'energy revolution', a man was consuming about 20.000 kcal/day. Today, in industrialized countries and if we include all forms of energies (space heating, transport, production, feeding etc.) this consumption reaches up to 230.000 kcal/day. We have reached a 'power society' which has put no limit to its growth needs. However, this growth is based on an immoderate consumption of fossil fuels which are on the way of exhaustion. A new energy revolution appears as inevitable to us, but will it be similar or in opposition to the previous ones? This revolution will have to integrate a new parameter: the need to fit with a sustainable development philosophy. To determine the conditions of this revolution, it is useful to analyse the energy systems from the needs to the resources, in a historical, philosophical and technical manner. Starting from this analysis, this book explores the possibilities to build the transition towards this new energy revolution. (J.S.)

Bandwidth-Efficient Communication through 225 MHz Ka-band Relay Satellite Channel

Science.gov (United States)

Downey, Joseph; Downey, James; Reinhart, Richard C.; Evans, Michael Alan; Mortensen, Dale John

2016-01-01

The communications and navigation space infrastructure of the National Aeronautics and Space Administration (NASA) consists of a constellation of relay satellites (called Tracking and Data Relay Satellites (TDRS)) and a global set of ground stations to receive and deliver data to researchers around the world from mission spacecraft throughout the solar system. Planning is underway to enhance and transform the infrastructure over the coming decade. Key to the upgrade will be the simultaneous and efficient use of relay transponders to minimize cost and operations while supporting science and exploration spacecraft. Efficient use of transponders necessitates bandwidth efficient communications to best use and maximize data throughput within the allocated spectrum. Experiments conducted with NASA's Space Communication and Navigation (SCaN) Testbed on the International Space Station provides a unique opportunity to evaluate advanced communication techniques, such as bandwidth-efficient modulations, in an operational flight system. Demonstrations of these new techniques in realistic flight conditions provides critical experience and reduces the risk of using these techniques in future missions. Efficient use of spectrum is enabled by using high-order modulations coupled with efficient forward error correction codes. This paper presents a high-rate, bandwidth-efficient waveform operating over the 225 MHz Ka-band service of the TDRS System (TDRSS). The testing explores the application of Gaussian Minimum Shift Keying (GMSK), 248-phase shift keying (PSK) and 1632- amplitude PSK (APSK) providing over three bits-per-second-per-Hertz (3 bsHz) modulation combined with various LDPC encoding rates to maximize throughput. With a symbol rate of 200 Mbaud, coded data rates of 1000 Mbps were tested in the laboratory and up to 800 Mbps over the TDRS 225 MHz channel. This paper will present on the high-rate waveform design, channel characteristics, performance results, compensation

Crosstalk cancellation on linearly and circularly polarized communications satellite links

Science.gov (United States)

Overstreet, W. P.; Bostian, C. W.

1979-01-01

The paper discusses the cancellation network approach for reducing crosstalk caused by depolarization on a dual-polarized communications satellite link. If the characteristics of rain depolarization are sufficiently well known, the cancellation network can be designed in a way that reduces system complexity, the most important parameter being the phase of the cross-polarized signal. Relevant theoretical calculations and experimental data are presented. The simplicity of the cancellation system proposed makes it ideal for use with small domestic or private earth terminals.

Do future commercial broadband communication satellites really need laser-communication intersatellite links (ISLs)?

Science.gov (United States)

Freidell, James E.

1997-04-01

Large commercial satellite programs requiring ISLs are growing in number and maturing. An important segment of the commercial satellite market, and its ISL needs, is discussed in the paper. ISL value will increase as long-haul terrestrial backbones become increasingly congested. Providing interregional and intercontinental connectivity via ISL presents far lower cost and fewer problems than relying on terrestrial fiber-optic networks. To demonstrate this, a new metric is proposed which allows 'apples-to- apples' cost/performance comparisons between laser communications in GEO, LEO, and terrestrial fiber-optics. ISL requirements in to the next decade are predicted >= 50-100 Gb/s full duplex. Many attitudinal changes must be embraced among those who choose to focus on this new commercial business. Foremost among these is a preponderance to delivering fully acceptable hardware fast and at low cost, as opposed to merely designing such. Considerable attention must be given business considerations foreign to professionals who have spent time in the government or government contracting sectors. Successful ISL customers will come to recognize that ISLs are not commodity products. Failure to embrace these attitudes will nonetheless constitute decision to which the commercial market, and particularly the financial market, will appropriately respond.

Positional stabilization of communications satellites - The RITA ion propulsion system is ready for commercial use

Science.gov (United States)

The radiofrequency ion thruster assembly (RITA) intended for service aboard the new Artemis communications satellite will operate for three hours twice a day, in order to furnish orbital position adjustments that keep antennas accurately pointed toward the earth. These engines are, despite such frequent and sustained use, projected to eject no more than 30 kG of Xe over the course of a decade. RITA operation is also extremely reliable and, due to its very low propellant consumption, is the basis of a long satellite service life. RITA will be among the 15 experiments that are to be performed by ESA's Eureca research satellite.

Virtual target tracking (VTT) as applied to mobile satellite communication networks

Science.gov (United States)

Amoozegar, Farid

1999-08-01

Traditionally, target tracking has been used for aerospace applications, such as, tracking highly maneuvering targets in a cluttered environment for missile-to-target intercept scenarios. Although the speed and maneuvering capability of current aerospace targets demand more efficient algorithms, many complex techniques have already been proposed in the literature, which primarily cover the defense applications of tracking methods. On the other hand, the rapid growth of Global Communication Systems, Global Information Systems (GIS), and Global Positioning Systems (GPS) is creating new and more diverse challenges for multi-target tracking applications. Mobile communication and computing can very well appreciate a huge market for Cellular Communication and Tracking Devices (CCTD), which will be tracking networked devices at the cellular level. The objective of this paper is to introduce a new concept, i.e., Virtual Target Tracking (VTT) for commercial applications of multi-target tracking algorithms and techniques as applied to mobile satellite communication networks. It would be discussed how Virtual Target Tracking would bring more diversity to target tracking research.

SAW based systems for mobile communications satellites

Science.gov (United States)

Peach, R. C.; Miller, N.; Lee, M.

1993-01-01

Modern mobile communications satellites, such as INMARSAT 3, EMS, and ARTEMIS, use advanced onboard processing to make efficient use of the available L-band spectrum. In all of these cases, high performance surface acoustic wave (SAW) devices are used. SAW filters can provide high selectivity (100-200 kHz transition widths), combined with flat amplitude and linear phase characteristics; their simple construction and radiation hardness also makes them especially suitable for space applications. An overview of the architectures used in the above systems, describing the technologies employed, and the use of bandwidth switchable SAW filtering (BSSF) is given. The tradeoffs to be considered when specifying a SAW based system are analyzed, using both theoretical and experimental data. Empirical rules for estimating SAW filter performance are given. Achievable performance is illustrated using data from the INMARSAT 3 engineering model (EM) processors.

A design proposal of a certain missile tactical command system based on Beidou satellite communication and GPS positioning techniques

Science.gov (United States)

Ma, Jian; Hao, Yongsheng; Miao, Jian; Zhang, Jianmao

2007-11-01

This paper introduced a design proposal of tactical command system that applied to a kind of anti-tank missile carriers. The tactical command system was made up of embedded computer system based on PC104 bus, Linux operating system, digital military map, Beidou satellite communication equipments and GPS positioning equipments. The geographic coordinates was measured by the GPS receiver, the positioning data, commands and information were transmitted real-time between tactical command systems, tactical command systems and command center, by the Beidou satellite communication systems. The Beidou satellite communication equipments and GPS positioning equipments were integrated to an independent module, exchanging data with embedded computer through RS232 serial ports and USB ports. The decision support system software based on information fusion, calculates positioning data, geography information and battle field information synthetically, shows the position of allies and the position of enemy on the military map, and assesses the various threats of different enemy objects, educes a situation assessment and threat assessment.

TYCHO: Demonstrator and operational satellite mission to Earth-Moon-Libration point EML-4 for communication relay provision as a service

Science.gov (United States)

Hornig, Andreas; Homeister, Maren

2015-03-01

In the current wake of mission plans to the Moon and to Earth-Moon Libration points (EML) by several agencies and organizations, TYCHO identifies the key role of telecommunication provision for the future path of lunar exploration. It demonstrates an interesting extension to existing communication methods to the Moon and beyond by combining innovative technology with a next frontier location and the commercial space communication sector. It is evident that all communication systems will rely on direct communication to Earth ground stations. In case of EML-2 missions around HALO orbits or bases on the far side of the Moon, it has to be extended by communication links via relay stations. The innovative approach is that TYCHO provides this relay communication to those out-of-sight lunar missions as a service. TYCHO will establish a new infrastructure for future missions and even create a new market for add-on relay services. The TMA-0 satellite is TYCHO's first phase and a proposed demonstrator mission to the Earth-Moon Libration point EML-4. It demonstrates relay services needed for automated exploratory and manned missions (Moon bases) on the rim (>90°E and >90°W) and far side surface, to lunar orbits and even to EML-2 halo orbits (satellites and space stations). Its main advantage is the permanent availability of communication coverage. This will provide full access to scientific and telemetry data and furthermore to crucial medical monitoring and safety. The communication subsystem is a platform for conventional communication but also a test-bed for optical communication with high data-rate LASER links to serve the future needs of manned bases and periodic burst data-transfer from lunar poles. The operational TMA-1 satellite is a stand-alone mission integrated into existing space communication networks to provide open communication service to external lunar missions. Therefore the long-time stable libration points EML-4 and -5 are selected to guarantee an

Studying The Great Russian Revolution

Directory of Open Access Journals (Sweden)

A. V. Torkunov

2017-01-01

Full Text Available The article revises an established view of Russian Revolution as two separate events - February Revolution and October Revolution. The author supports the concept of the «Great Russian Revolution», which unites these two events in a single process of revolutionary development. The author draws attention to the following advantages of the concept under consideration. First, it conceptualizes the revolution as a process contingent of a local and global historical context. In this sense, the revolution is presented as the transition of society to the modern stage of development, meaning the transition to modernity. Second, revolutionary events in Russia are considered from the point of view of the evolution of the spatial and socioeconomic distribution and rearrangement of key social groups: peasantry, elites, national and ethnic minorities. Third, it takes into account the personal factor in the revolutionary events, the influence of individual personalities on escalation or the reduction of socio-political tensions. Fourth, it draws attention to the fact that revolutions imply the use of various forms of political violence. Each revolution is characterized by a unique correlation of forms and intensity of political violence. Finally, it gives a normative assessment of the Revolution, encouraging a national discussion on the results and consequences of this great event.

Multiple wavelength spectral system simulating background light noise environment in satellite laser communications

Science.gov (United States)

Lu, Wei; Sun, Jianfeng; Hou, Peipei; Xu, Qian; Xi, Yueli; Zhou, Yu; Zhu, Funan; Liu, Liren

2017-08-01

Performance of satellite laser communications between GEO and LEO satellites can be influenced by background light noise appeared in the field of view due to sunlight or planets and some comets. Such influences should be studied on the ground testing platform before the space application. In this paper, we introduce a simulator that can simulate the real case of background light noise in space environment during the data talking via laser beam between two lonely satellites. This simulator can not only simulate the effect of multi-wavelength spectrum, but also the effects of adjustable angles of field-of-view, large range of adjustable optical power and adjustable deflection speeds of light noise in space environment. We integrate these functions into a device with small and compact size for easily mobile use. Software control function is also achieved via personal computer to adjust these functions arbitrarily. Keywords:

“Si Nicaragua Venció”: Lesbian and Gay Solidarity with the Revolution

Directory of Open Access Journals (Sweden)

Emily K. Hobson

2012-12-01

Full Text Available This article analyzes the radical imagination of lesbian and gay activism in solidarity with the Nicaraguan Revolution. It examines the reasons US lesbian and gay radicals supported that revolution and investigates the ways that homoerotic, especially lesbian, desire shaped their solidarity. Drawing on Herbert Marcuse and Michel Foucault, the article argues that lesbian and gay radicals viewed the Nicaraguan Revolution in erotic and heterotopic terms. Posters, fliers, and interviews reveal that US activists, people of color and white, represented the Revolution and solidarity through tropes of female masculinity and women’s affection. Many Nicaraguan lesbians and gay men shared these nonnormative images of socialist change. Yet while Nicaraguans claimed Sandinismo as their own, for US activists revolution remained a distant object of desire and solidarity a “seduction,” “crush,” or embrace.  United States activists who embraced developmentalist views of Latin American sexualities remained unable to witness lesbian and gay life inside Nicaragua, while lesbian and gay Sandinistas kept silent about FSLN homophobia so as not to undermine solidarity against the Contra war. Desire served as a powerful tool for mobilizing transnational solidarity. By failing to examine desire critically, however, US activists limited their communications with Nicaraguan lesbians and gay men and weakened the relationship they sought with revolution itself.

Mobile satellite communications in the 1990's

Science.gov (United States)

Singh, Jai

1992-07-01

The evolution of Inmarsat global services from a single market and single service of the 1980's to all of the key mobile markets and a wide range of new terminals and services in the 1990's is described. An overview of existing mobile satellite services, as well as new services under implementation for introduction in the near and longer term, including a handheld satellite phone (Inmarsat-P), is provided. The initiative taken by Inmarsat in the integration of its global mobile satellite services with global navigation capability derived from GPS (Global Positioning System) and the GLONASS (Russian GPS) navigation satellite systems and the provision of an international civil overlay for GPS/GLONASS integrity and augmentation is highlighted. To complete the overview of the development of mobile satellite services in the 1990's, the known national and regional mobile satellite system plans and the various recent proposals for both orbiting and geostationary satellite systems for proving handheld satellite phone and/or data messaging services are described.

Modulation Classification of Satellite Communication Signals Using Cumulants and Neural Networks

Science.gov (United States)

Smith, Aaron; Evans, Michael; Downey, Joseph

2017-01-01

National Aeronautics and Space Administration (NASA)'s future communication architecture is evaluating cognitive technologies and increased system intelligence. These technologies are expected to reduce the operational complexity of the network, increase science data return, and reduce interference to self and others. In order to increase situational awareness, signal classification algorithms could be applied to identify users and distinguish sources of interference. A significant amount of previous work has been done in the area of automatic signal classification for military and commercial applications. As a preliminary step, we seek to develop a system with the ability to discern signals typically encountered in satellite communication. Proposed is an automatic modulation classifier which utilizes higher order statistics (cumulants) and an estimate of the signal-to-noise ratio. These features are extracted from baseband symbols and then processed by a neural network for classification. The modulation types considered are phase-shift keying (PSK), amplitude and phase-shift keying (APSK),and quadrature amplitude modulation (QAM). Physical layer properties specific to the Digital Video Broadcasting - Satellite- Second Generation (DVB-S2) standard, such as pilots and variable ring ratios, are also considered. This paper will provide simulation results of a candidate modulation classifier, and performance will be evaluated over a range of signal-to-noise ratios, frequency offsets, and nonlinear amplifier distortions.

Bandwidth-Efficient Communication through 225 MHz Ka-band Relay Satellite Channel

Science.gov (United States)

Downey, Joseph A.; Downey, James M.; Reinhart, Richard C.; Evans, Michael A.; Mortensen, Dale J.

2016-01-01

The communications and navigation space infrastructure of the National Aeronautics and Space Administration (NASA) consists of a constellation of relay satellites (called Tracking and Data Relay Satellites (TDRS)) and a global set of ground stations to receive and deliver data to researchers around the world from mission spacecraft throughout the solar system. Planning is underway to enhance and transform the infrastructure over the coming decade. Key to the upgrade will be the simultaneous and efficient use of relay transponders to minimize cost and operations while supporting science and exploration spacecraft. Efficient use of transponders necessitates bandwidth efficient communications to best use and maximize data throughput within the allocated spectrum. Experiments conducted with NASA's Space Communication and Navigation (SCaN) Testbed on the International Space Station provides a unique opportunity to evaluate advanced communication techniques, such as bandwidth-efficient modulations, in an operational flight system. Demonstrations of these new techniques in realistic flight conditions provides critical experience and reduces the risk of using these techniques in future missions. Efficient use of spectrum is enabled by using high-order modulations coupled with efficient forward error correction codes. This paper presents a high-rate, bandwidth-efficient waveform operating over the 225 MHz Ka-band service of the TDRS System (TDRSS). The testing explores the application of Gaussian Minimum Shift Keying (GMSK), 2/4/8-phase shift keying (PSK) and 16/32- amplitude PSK (APSK) providing over three bits-per-second-per-Hertz (3 b/s/Hz) modulation combined with various LDPC encoding rates to maximize through- put. With a symbol rate of 200 M-band, coded data rates of 1000 Mbps were tested in the laboratory and up to 800 Mbps over the TDRS 225 MHz channel. This paper will present on the high-rate waveform design, channel characteristics, performance results

Power attenuation characteristics as switch-over criterion in personal satellite mobile communications

Science.gov (United States)

Castro, Jonathan P.

1993-01-01

A third generation mobile system intends to support communications in all environments (i.e., outdoors, indoors at home or office and when moving). This system will integrate services that are now available in architectures such as cellular, cordless, mobile data networks, paging, including satellite services to rural areas. One way through which service integration will be made possible is by supporting a hierarchical cellular structure based on umbrella cells, macro cells, micro and pico cells. In this type of structure, satellites are part of the giant umbrella cells allowing continuous global coverage, the other cells belong to cities, neighborhoods, and buildings respectively. This does not necessarily imply that network operation of terrestrial and satellite segments interconnect to enable roaming and spectrum sharing. However, the cell concept does imply hand-off between different cell types, which may involve change of frequency. Within this propsective, the present work uses power attenuation characteristics to determine a dynamic criterion that allows smooth transition from space to terrestrial networks. The analysis includes a hybrid channel that combines Rician, Raleigh and Log Normal fading characteristics.

Advanced architectures and the required technologies for next-generation communications satellite systems

Science.gov (United States)

Arnold, Ray; Naderi, F. Michael

1988-01-01

The hardware requirements for multibeam operation and onboard data processing and switching on future communication satellites are reviewed. Topics addressed include multiple-beam antennas, frequency-addressable beams, baseband vs IF switching, FDM/TDMA systems, and bulk demodulators. The proposed use of these technologies in the NASA ACTS, Italsat, and the Japanese ETS-VI is discussed in detail and illustrated with extensive diagrams, maps, drawings, and tables of projected performance data.

Link establishment criterion and topology optimization for hybrid GPS satellite communications with laser crosslinks

Science.gov (United States)

Li, Lun; Wei, Sixiao; Tian, Xin; Hsieh, Li-Tse; Chen, Zhijiang; Pham, Khanh; Lyke, James; Chen, Genshe

2018-05-01

In the current global positioning system (GPS), the reliability of information transmissions can be enhanced with the aid of inter-satellite links (ISLs) or crosslinks between satellites. Instead of only using conventional radio frequency (RF) crosslinks, the laser crosslinks provide an option to significantly increase the data throughput. The connectivity and robustness of ISL are needed for analysis, especially for GPS constellations with laser crosslinks. In this paper, we first propose a hybrid GPS communication architecture in which uplinks and downlinks are established via RF signals and crosslinks are established via laser links. Then, we design an optical crosslink assignment criteria considering the practical optical communication factors such as optical line- of-sight (LOS) range, link distance, and angular velocity, etc. After that, to further improve the rationality of establishing crosslinks, a topology control algorithm is formulated to optimize GPS crosslink networks at both physical and network layers. The RF transmission features for uplink and downlink and optical transmission features for crosslinks are taken into account as constraints for the optimization problem. Finally, the proposed link establishment criteria are implemented for GPS communication with optical crosslinks. The designs of this paper provide a potential crosslink establishment and topology control algorithm for the next generation GPS.

Prediction of the Sun-Glint Locations for the Communication, Ocean and Meteorological Satellite

Directory of Open Access Journals (Sweden)

Jae-Ik Park

2005-09-01

Full Text Available For the Communication, Ocean and Meteorological Satellite (COMS which will be launched in 2008, an algorithm for finding the precise location of the sun-glint point on the ocean surface is studied. The precise locations of the sun-glint are estimated by considering azimuth and elevation angles of Sun-satellite-Earth geometric position and the law of reflection. The obtained nonlinear equations are solved by using the Newton-Raphson method. As a result, when COMS is located at 116.2°E or 128.2°E longitude, the sun-glint covers region of ±10° (N-S latitude and 80-150° (E-W longitude. The diurnal path of the sun-glint in the southern hemisphere is curved towards the North Pole, and the path in the northern hemisphere is forwards the south pole. The algorithm presented in this paper can be applied to predict the precise location of sun-glint region in any other geostationary satellites.

Marxism as permanent revolution

OpenAIRE

van Ree, E.

2013-01-01

This article argues that the 'permanent revolution' represented the dominant element in Karl Marx and Friedrich Engels' political discourse, and that it tended to overrule considerations encapsulated in 'historical materialism'. In Marx and Engels's understanding, permanent revolution did not represent a historical shortcut under exceptional circumstances, but the course revolutions in the modern era would normally take. Marx and Engels traced back the pattern to the sixteenth century. It is ...

High Data Rate Satellite Communications for Environmental Remote Sensing

Science.gov (United States)

Jackson, J. M.; Munger, J.; Emch, P. G.; Sen, B.; Gu, D.

2014-12-01

Satellite to ground communication bandwidth limitations place constraints on current earth remote sensing instruments which limit the spatial and spectral resolution of data transmitted to the ground for processing. Instruments such as VIIRS, CrIS and OMPS on the Soumi-NPP spacecraft must aggregate data both spatially and spectrally in order to fit inside current data rate constraints limiting the optimal use of the as-built sensors. Future planned missions such as HyspIRI, SLI, PACE, and NISAR will have to trade spatial and spectral resolution if increased communication band width is not made available. A number of high-impact, environmental remote sensing disciplines such as hurricane observation, mega-city air quality, wild fire detection and monitoring, and monitoring of coastal oceans would benefit dramatically from enabling the downlinking of sensor data at higher spatial and spectral resolutions. The enabling technologies of multi-Gbps Ka-Band communication, flexible high speed on-board processing, and multi-Terabit SSRs are currently available with high technological maturity enabling high data volume mission requirements to be met with minimal mission constraints while utilizing a limited set of ground sites from NASA's Near Earth Network (NEN) or TDRSS. These enabling technologies will be described in detail with emphasis on benefits to future remote sensing missions currently under consideration by government agencies.

An Irish Revolution Without A Revolution

Directory of Open Access Journals (Sweden)

Aidan Beatty

2016-03-01

Full Text Available There is a conventional view among Irish historians that a revolution occurred in that country between the passing of the Third Home Rule Bill of 1912 and the end of the Civil War in 1923.  The violence of those years, the collapse in support for the Irish Parliamentary Party (IPP, the meteoric rise to power of Sinn Féin, a new sense of meritocracy, a greater sense of democracy and a widespread radicalism; all are seen as elements of a major change in Irish politics and life, a ‘Revolution.’  Drawing on Gramsci's notion of a “revolution without a revolution”, this paper seeks to understand the events in Ireland of 1912-23, not as a sudden rupture with the past but as the culmination of a much longer period of (often British-backed capitalist development in post-Famine Ireland. This paper argues that Irish nationalist politics in the decades before 1912 is better understood via categories such as class, gender, capitalism and the pervasive power of the British state.  As such, as well as pursuing a reassessment of the project of Irish historical development and state-building, this paper also seeks a reassessment of the project of (an equally statist Irish historiography.

A systems approach to the commercialization of space communications technology - The NASA/JPL Mobile Satellite Program

Science.gov (United States)

Weber, William J., III; Gray, Valerie W.; Jackson, Byron; Steele, Laura C.

1991-10-01

This paper discusss the systems approach taken by NASA and the Jet Propulsion Laboratory in the commercialization of land-mobile satellite services (LMSS) in the United States. As the lead center for NASA's Mobile Satellite Program, JPL was involved in identifying and addressing many of the key barriers to commercialization of mobile satellite communications, including technical, economic, regulatory and institutional risks, or uncertainties. The systems engineering approach described here was used to mitigate these risks. The result was the development and implementation of the JPL Mobile Satellite Experiment Project. This Project included not only technology development, but also studies to support NASA in the definition of the regulatory, market, and investment environments within which LMSS would evolve and eventually operate, as well as initiatives to mitigate their associated commercialization risks. The end result of these government-led endeavors was the acceleration of the introduction of commercial mobile satellite services, both nationally and internationally.

Deviations in CBERS-4 Satellite Direction Components From The Electromagnetic Disturbance of Communication Antennas

Science.gov (United States)

Heilmann, A.; Fernandes, C.

2017-10-01

The CBERS-4 is a low Earth orbit satellite, with a set of antennas S-band/UHF for communication almost omni-direcional. For the electromagnetic radiation from transmission antennas, was developed a model of electromagnetic disturbance considering the antennas theory and the laws of the conservation energy-momentum. Was propagated the orbit of the CBERS-4 satellite considering your state vector from the March 14, 2016, at 11h 14m 15.23s using the equation of motion in the form of cartesian components. From the state vector of the CBERS-4 satellite was possible to propagate the orbit for different periods, without disturbance (considering just the problem of two bodies) and with a disturbance of electromagnetic origin. The model of reaction of electromagnetic acceleration on the satellite depends on only the type of antenna. Quadrifilar and parabolic propeller antennas were considered in this paper. Using the equation of motion of the satellite based on the method of Runge-Kutta of fourth and fifth degree, the effect disturber this modeling was applied on the CBERS-4 considering the mass of satellite, characteristics of antenna, power irradiated and gain maximum of antenna. The final analysis discusses the values of components in the direction (radial, cross and normal) and the coordinates X-Y-Z considering the case disturbed to both antennas.

A Strategic Analysis of Commercial Satellite communications Enterprises and their Role for the Warfighter of the Future

National Research Council Canada - National Science Library

Gonder, Richard

1998-01-01

.... After initially setting the baseline, the paper will discuss the ability of the exploding commercial satellite communications market to meet some, if not most of the uniquely military requirements (the pros...

The Coming Primary Care Revolution.

Science.gov (United States)

Ellner, Andrew L; Phillips, Russell S

2017-04-01

The United States has the most expensive, technologically advanced, and sub-specialized healthcare system in the world, yet it has worse population health status than any other high-income country. Rising healthcare costs, high rates of waste, the continued trend towards chronic non-communicable disease, and the growth of new market entrants that compete with primary care services have set the stage for fundamental change in all of healthcare, driven by a revolution in primary care. We believe that the coming primary care revolution ought to be guided by the following design principles: 1) Payment must adequately support primary care and reward value, including non-visit-based care. 2) Relationships will serve as the bedrock of value in primary care, and will increasingly be fostered by teams, improved clinical operations, and technology, with patients and non-physicians assuming an ever-increasing role in most aspects of healthcare. 3) Generalist physicians will increasingly focus on high-acuity and high-complexity presentations, and primary care teams will increasingly manage conditions that specialists managed in the past. 4) Primary care will refocus on whole-person care, and address health behaviors as well as vision, hearing, dental, and social services. Design based on these principles should lead to higher-value healthcare, but will require new approaches to workforce training.

Summary of the CTS Transient Event Counter data after one year of operation. [Communication Technology Satellite

Science.gov (United States)

Stevens, N. J.; Klinect, V. W.; Gore, J. V.

1977-01-01

The environmental charging of satellite surfaces during geomagnetic substorms is the apparent cause of a significant number of anomalous events occurring on geosynchronous satellites since the early 1970's. Electromagnetic pulses produced in connection with the differential charging of insulators can couple into the spacecraft harness and cause electronic switching anomalies. An investigation conducted to determine the response of the spacecraft surfaces to substorm particle fluxes makes use of a harness transient detector. The harness transient detector, called the Transient Event Counter (TEC) was built and integrated into the Canadian-American Communications Technology Satellite (CTS). A description of the TEC and its operational characteristics is given and the obtained data are discussed. The data show that the satellite surfaces appear to be charged to the point that discharges occur and that the discharge-induced transients couple into the wire harnesses.

The design of a linear L-band high power amplifier for mobile communication satellites

Science.gov (United States)

Whittaker, N.; Brassard, G.; Li, E.; Goux, P.

1990-01-01

A linear L-band solid state high power amplifier designed for the space segment of the Mobile Satellite (MSAT) mobile communication system is described. The amplifier is capable of producing 35 watts of RF power with multitone signal at an efficiency of 25 percent and with intermodulation products better than 16 dB below carrier.

[Mobile hospital -real time mobile telehealthcare system with ultrasound and CT van using high-speed satellite communication-].

Science.gov (United States)

Takizawa, Masaomi; Miyashita, Toyohisa; Murase, Sumio; Kanda, Hirohito; Karaki, Yoshiaki; Yagi, Kazuo; Ohue, Toru

2003-01-01

A real-time telescreening system is developed to detect early diseases for rural area residents using two types of mobile vans with a portable satellite station. The system consists of a satellite communication system with 1.5Mbps of the JCSAT-1B satellite, a spiral CT van, an ultrasound imaging van with two video conference system, a DICOM server and a multicast communication unit. The video image and examination image data are transmitted from the van to hospitals and the university simultaneously. Physician in the hospital observes and interprets exam images from the van and watches the video images of the position of ultrasound transducer on screenee in the van. After the observation images, physician explains a results of the examination by the video conference system. Seventy lung CT screening and 203 ultrasound screening were done from March to June 2002. The trial of this real time screening suggested that rural residents are given better healthcare without visit to the hospital. And it will open the gateway to reduce the medical cost and medical divide between city area and rural area.

The dual Green Revolutions in South Korea: reforestation and agricultural revolution under the authoritarian regime.

Science.gov (United States)

Moon, Manyong

2012-01-01

In South Korea, the Green Revolution has been commonly understood as the development and dissemination of new rice varieties ('Tongil' rice) and the rapid increase of rice yield in the 1970s. However, revolutionary success in agriculture was not the only green revolution South Korea experienced; another green revolution lay in the success of reforestation projects. In the 1970s, South Korea's forest greening was closely related to its agricultural revolution in several ways. Therefore, South Korea's Green Revolution was an intrinsically linked double feature of agriculture and forestry. This two-pronged revolution was initiated by scientific research - yet accomplished by the strong administrative mobilization of President Park Chung Hee's regime. The process of setting goals and meeting them through a military-like strategy in a short time was made possible under the authoritarian regime, known as 'Yushin', though the administration failed to fully acknowledge scientific expertise in the process of pushing to achieve goals.

Spacecraft design project: Low Earth orbit communications satellite

Science.gov (United States)

Moroney, Dave; Lashbrook, Dave; Mckibben, Barry; Gardener, Nigel; Rivers, Thane; Nottingham, Greg; Golden, Bill; Barfield, Bill; Bruening, Joe; Wood, Dave

1991-01-01

This is the final product of the spacecraft design project completed to fulfill the academic requirements of the Spacecraft Design and Integration 2 course (AE-4871) taught at the U.S. Naval Postgraduate School. The Spacecraft Design and Integration 2 course is intended to provide students detailed design experience in selection and design of both satellite system and subsystem components, and their location and integration into a final spacecraft configuration. The design team pursued a design to support a Low Earth Orbiting (LEO) communications system (GLOBALSTAR) currently under development by the Loral Cellular Systems Corporation. Each of the 14 team members was assigned both primary and secondary duties in program management or system design. Hardware selection, spacecraft component design, analysis, and integration were accomplished within the constraints imposed by the 11 week academic schedule and the available design facilities.

Mexican Revolution

OpenAIRE

Scheuzger, Stephan

2016-01-01

It was the complex and far-reaching transformation of the Mexican Revolution rather than the First World War that left its mark on Mexican history in the second decade of the 20th century. Nevertheless, although the country maintained its neutrality in the international conflict, it was a hidden theatre of war. Between 1914 and 1918, state actors in Germany, Great Britain and the United States defined their policies towards Mexico and its nationalist revolution with a view not only to improve...

The American Satellite Company (ASC) satellite deployed from payload bay

Science.gov (United States)

1985-01-01

The American Satellite Company (ASC) communications satellite is deployed from the payload bay of the Shuttle Discovery. A portion of the cloudy surface of the earth can be seen to the left of the frame.

Wars, Revolutions and the First Real World Revolution

Directory of Open Access Journals (Sweden)

Petri Minkkinen

2009-12-01

Full Text Available El objetivo de este artículo es promover la discusión conceptual para una publicación más amplia “Los Ciclos del Imperialismo, Guerra, y Revolución”. Empieza desde una presuposición que nuestro mundo común esta atravesando una transición desde un contexto histórico amplio eurocéntrico hacia un contexto histórico amplio non-eurocéntrico. Continua con la discusión histórica de los conceptos relacionados con la guerra, la reforma y la revolución y explica porque, en el contexto de la fase actual de la transición mundial y la Primera Verdadera Guerra Mundial, a pesar de la discusión anterior acerca de las revoluciones y revoluciones mundiales, es razonable sugerir que nuestro mundo común esta atravesando la Primera Verdadera Revolución Mundial._____________________ABSTRACTThe purpose of this article is to engage in a conceptual discussion for a broader publication on “The Cycles of Imperialism, War and Revolution”. It departs from a presupposition that our common world is experiencing a transition from a broad Eurocentric historical context into a non-Eurocentric broad historical context. It proceeds by a historical discussion on the concepts related to wars, reforms and revolutions and explains why, in the context of the actual phase of global transition and the First Real World War, it is, despite earlier discussions on revolutions and world revolutions, meaningful to suggest that our common world is experiencing a First Real World Revolution.

The Mexican Revolution and health care or the health of the Mexican Revolution.

Science.gov (United States)

Horn, J J

1985-01-01

Despite a victorious social revolution, a self-proclaimed "revolutionary" government, and a significant post-war economic growth, Mexico has not achieved a just or equitable social system. The Mexican Revolution led to the emergence of a new bureaucratic class whose "trickle-down" development strategy sacrificed social welfare to capital accumulation. Mexican morbidity and mortality patterns resemble those of more impoverished developing nations without revolutionary experience. The patterns of health care in Mexico reflect inequities and contradictions in the society and economy at large and flow from the erosion of the egalitarian aims of the revolution concomitant with the expansion of capitalism and the concentration of the benefits of "modernization" in the hands of privileged elites. Mexico's health problems are symptomatic of a general socio-economic malaise which questions the legitimacy of the Revolution.

Trellis coding with Continuous Phase Modulation (CPM) for satellite-based land-mobile communications

Science.gov (United States)

1989-01-01

This volume of the final report summarizes the results of our studies on the satellite-based mobile communications project. It includes: a detailed analysis, design, and simulations of trellis coded, full/partial response CPM signals with/without interleaving over various Rician fading channels; analysis and simulation of computational cutoff rates for coherent, noncoherent, and differential detection of CPM signals; optimization of the complete transmission system; analysis and simulation of power spectrum of the CPM signals; design and development of a class of Doppler frequency shift estimators; design and development of a symbol timing recovery circuit; and breadboard implementation of the transmission system. Studies prove the suitability of the CPM system for mobile communications.

Description and Simulation of a Fast Packet Switch Architecture for Communication Satellites

Science.gov (United States)

Quintana, Jorge A.; Lizanich, Paul J.

1995-01-01

The NASA Lewis Research Center has been developing the architecture for a multichannel communications signal processing satellite (MCSPS) as part of a flexible, low-cost meshed-VSAT (very small aperture terminal) network. The MCSPS architecture is based on a multifrequency, time-division-multiple-access (MF-TDMA) uplink and a time-division multiplex (TDM) downlink. There are eight uplink MF-TDMA beams, and eight downlink TDM beams, with eight downlink dwells per beam. The information-switching processor, which decodes, stores, and transmits each packet of user data to the appropriate downlink dwell onboard the satellite, has been fully described by using VHSIC (Very High Speed Integrated-Circuit) Hardware Description Language (VHDL). This VHDL code, which was developed in-house to simulate the information switching processor, showed that the architecture is both feasible and viable. This paper describes a shared-memory-per-beam architecture, its VHDL implementation, and the simulation efforts.

Data manage and communication of lunar orbital X-ray imaging analyzer in CE-1 satellite

International Nuclear Information System (INIS)

Wang Jinzhou; Wang Huanyu; Zhang Chengmo; Liang Xiaohua; Gao Min; CaoXuelei; Zhang Jiayu; Peng Wenxi; Cui Xingzhu; Xu Yupeng; Zhang Yongjie

2006-01-01

We present the software design for data management and communication software designed for the Lunar Orbital X-ray Imaging Analyzer in CE-1 Satellite. The software uses the appropriate format to assemble science data package and appropriate command respond mode, realizes the data transferring tasks through the 1553B bus on time, event though the channel bandwidth is under the limited. Also, the memory distribution and management of LOXIA (remote terminal) that fitted the communication with BC(Bus Controller) was introduced. Furthermore, for the spatial application, the security and reliability of software are emphasized. (authors)

en uislamisk revolution

DEFF Research Database (Denmark)

Mathiesen, Kasper

2011-01-01

artiklen diskuterer det teologiske grundlag for de arabiske opstande. Er det tilladt ifølge islamisk lov at lave revolution på det grundlag der kendetegner den arabiske verden i 2011?......artiklen diskuterer det teologiske grundlag for de arabiske opstande. Er det tilladt ifølge islamisk lov at lave revolution på det grundlag der kendetegner den arabiske verden i 2011?...

Proceedings of the Twenty-First NASA Propagation Experimenters Meeting (NAPEX XXI) and the Advanced Communications Technology Satellite (ACTS) Propagation Studies Miniworkshop

Science.gov (United States)

Golshan, Nasser (Editor)

1997-01-01

The NASA Propagation Experimenters (NAPEX) meeting is convened each year to discuss studies supported by the NASA Propagation Program. Representatives from the satellite communications industry, academia and government who have an interest in space-ground radio wave propagation are invited to NAPEX meetings for discussions and exchange of information. The reports delivered at this meeting by program managers and investigators present recent activities and future plans. This forum provides an opportunity for peer discussion of work in progress, timely dissemination of propagation results, and close interaction with the satellite communications industry.

Marxism as permanent revolution

NARCIS (Netherlands)

van Ree, E.

2013-01-01

This article argues that the 'permanent revolution' represented the dominant element in Karl Marx and Friedrich Engels' political discourse, and that it tended to overrule considerations encapsulated in 'historical materialism'. In Marx and Engels's understanding, permanent revolution did not

Using satellite communications for a mobile computer network

Science.gov (United States)

Wyman, Douglas J.

1993-01-01

The topics discussed include the following: patrol car automation, mobile computer network, network requirements, network design overview, MCN mobile network software, MCN hub operation, mobile satellite software, hub satellite software, the benefits of patrol car automation, the benefits of satellite mobile computing, and national law enforcement satellite.

Defining a Communications Satellite Policy System for the 21st Century: A Model for a International Legal Framework and A New _Code of Conduct_

Science.gov (United States)

Pelton, Joseph N.

1996-02-01

This paper addresses the changing international communications environment and explores the key elements of a new policy framework for the 21st Century. It addresses the issues related to changing markets, trade considerations, standards, regulatory changes and international institutions and law. The most important aspects will related to new international policy and regulatory frameworks and in particular to a new international code of ethics and behavior in the field of satellite communications. A new communications satellite policy framework requires systematically addressing the following points: • Multi-lateral agreements at the nation state and the operating entity level • Systematic means to access both private and public capital • Meshing ITU regulations with regional and national policy guidelines including • landing rights" and national allocation procedures. • Systematic approach to local partnerships • Resolving the issue of the relative standing of various satellite systems (i.e. GEO, MEO, and LEO systems) • Resolving the rights, duties, and priorities of satellite facility providers versus types of service prviders. Beyond this policy framework and generalized legal infrastructure there is also another need. This is a need that arises from both increased globalism and competitive international markets. This is what might quite simply be called a "code of reasonable conduct:" To provide global and international communications services effectively and well in the 21st Century will require more than meeting minimum international legal requirements. A new "code of conduct" for global satellite communications will thus likely need to address: • Privacy and surveillance • Ethics of transborder data flow • Censorship and moral values • Cultural and linguistic sensitivity • Freedom of the press and respect for journalistic standards As expanding global information and telecommunications systems grow and impact every aspect of modern

Orbital resonances of Taiwan's FORMOSAT-2 remote sensing satellite

Science.gov (United States)

Lin, Shin-Fa; Hwang, Cheinway

2018-06-01

Unlike a typical remote sensing satellite that has a global coverage and non-integral orbital revolutions per day, Taiwan's FORMOSAT-2 (FS-2) satellite has a non-global coverage due to the mission requirements of one-day repeat cycle and daily visit around Taiwan. These orbital characteristics result in an integer number of revolutions a day and orbital resonances caused by certain components of the Earth's gravity field. Orbital flight data indicated amplified variations in the amplitudes of FS-2's Keplerian elements. We use twelve years of orbital observations and maneuver data to analyze the cause of the resonances and explain the differences between the simulated (at the pre-launch stage) and real orbits of FS-2. The differences are quantified using orbital perturbation theories that describe secular and long-period orbital evolutions caused by resonances. The resonance-induced orbital rising rate of FS-2 reaches +1.425 m/day, due to the combined (modeled) effect of resonances and atmospheric drags (the relative modeling errors remote sensing mission similar to FS-2, especially in the early mission design and planning phase.

Advanced Communication Technology Satellite (ACTS) Very Small Aperture Terminal (VSAT) Network Control Performance

Science.gov (United States)

Coney, T. A.

1996-01-01

This paper discusses the performance of the network control function for the Advanced Communications Technology Satellite (ACTS) very small aperture terminal (VSAT) full mesh network. This includes control of all operational activities such as acquisition, synchronization, timing and rain fade compensation as well as control of all communications activities such as on-demand integrated services (voice, video, and date) connects and disconnects Operations control is provided by an in-band orderwire carried in the baseboard processor (BBP) control burst, the orderwire burst, the reference burst, and the uplink traffic burst. Communication services are provided by demand assigned multiple access (DAMA) protocols. The ACTS implementation of DAMA protocols ensures both on-demand and integrated voice, video and data services. Communications services control is also provided by the in-band orderwire but uses only the reference burst and the uplink traffic burst. The performance of the ACTS network control functions have been successfully tested during on-orbit checkout and in various VSAT networks in day to day operations. This paper discusses the network operations and services control performance.

The 2017 Hurricane Season: A Revolution in Geostationary Weather Satellite Imaging and Data Processing

Science.gov (United States)

Weiner, A. M.; Gundy, J.; Brown-Bertold, B.; Yates, H.; Dobler, J. T.

2017-12-01

Since their introduction, geostationary weather satellites have enabled us to track hurricane life-cycle movement from development to dissipation. During the 2017 hurricane season, the new GOES-16 geostationary satellite demonstrated just how far we have progressed technologically in geostationary satellite imaging, with hurricane imagery showing never-before-seen detail of the hurricane eye and eyewall structure and life cycle. In addition, new ground system technology, leveraging high-performance computing, delivered imagery and data to forecasters with unprecedented speed—and with updates as often as every 30 seconds. As additional satellites and new products become operational, forecasters will be able to track hurricanes with even greater accuracy and assist in aftermath evaluations. This presentation will present glimpses into the past, a look at the present, and a prediction for the future utilization of geostationary satellites with respect to all facets of hurricane support.

Evolving earth-based and in-situ satellite network architectures for Mars communications and navigation support

Science.gov (United States)

Hastrup, Rolf; Weinberg, Aaron; McOmber, Robert

1991-09-01

Results of on-going studies to develop navigation/telecommunications network concepts to support future robotic and human missions to Mars are presented. The performance and connectivity improvements provided by the relay network will permit use of simpler, lower performance, and less costly telecom subsystems for the in-situ mission exploration elements. Orbiting relay satellites can serve as effective navigation aids by supporting earth-based tracking as well as providing Mars-centered radiometric data for mission elements approaching, in orbit, or on the surface of Mars. The relay satellite orbits may be selected to optimize navigation aid support and communication coverage for specific mission sets.

Multi-Satellite MIMO Communications at Ku-Band and Above: Investigations on Spatial Multiplexing for Capacity Improvement and Selection Diversity for Interference Mitigation

Directory of Open Access Journals (Sweden)

Liolis Konstantinos P

2007-01-01

Full Text Available This paper investigates the applicability of multiple-input multiple-output (MIMO technology to satellite communications at the Ku-band and above. After introducing the possible diversity sources to form a MIMO matrix channel in a satellite environment, particular emphasis is put on satellite diversity. Two specific different topics from the field of MIMO technology applications to satellite communications at these frequencies are further analyzed: (i capacity improvement achieved by MIMO spatial multiplexing systems and (ii interference mitigation achieved by MIMO diversity systems employing receive antenna selection. In the first case, a single-user capacity analysis of a satellite MIMO spatial multiplexing system is presented and a useful analytical closed form expression is derived for the outage capacity achieved. In the second case, a satellite MIMO diversity system with receive antenna selection is considered, adjacent satellite cochannel interference on its forward link is studied and an analytical model predicting the interference mitigation achieved is presented. In both cases, an appropriate physical MIMO channel model is assumed which takes into account the propagation phenomena related to the frequencies of interest, such as clear line-of-sight operation, high antenna directivity, the effect of rain fading, and the slant path lengths difference. Useful numerical results obtained through the analytical expressions derived are presented to compare the performance of multi-satellite MIMO systems to relevant single-input single-output (SISO ones.

Information and Communication Technology

DEFF Research Database (Denmark)

Kaila, Heidi Kristiina

2017-01-01

The emergence and development of the information and communication sector has been rapid in rural Viet Nam over 2006–14, and a true information and communication technology (ICT) revolution has taken place. This chapter examines household ownership and use of ICT. It studies the geographic and de...... wealthier and more educated than households with phones on average, the adoption patterns of these two technologies are very similar. ICT adoption is driven by education and income, as well as wealth and ownership of other technology.......The emergence and development of the information and communication sector has been rapid in rural Viet Nam over 2006–14, and a true information and communication technology (ICT) revolution has taken place. This chapter examines household ownership and use of ICT. It studies the geographic...... and demographic differences across ownership of technology, especially phones and the Internet, and the determinants of ICT adoption. First, it finds that expansion of telephones has been much more rapid than the expansion of the Internet. Second, it finds that even though in 2014 internet users were relatively...

Towards a new energy revolution?

International Nuclear Information System (INIS)

Rabourbin, Sabine

2011-01-01

At the time of the 19. century's 'energy revolution', a man was consuming about 20.000 kcal/day. Today, in industrialized countries and if we include all forms of energies (space heating, transport, production, feeding etc.) this consumption reaches up to 230.000 kcal/day. We have reached a 'power society' which has put no limit to its growth needs. However, this growth is based on an immoderate consumption of fossil fuels which are on the way of exhaustion. A new energy revolution appears as inevitable to us, but will it be similar or in opposition to the previous ones? This revolution will have to integrate a new parameter: the need to fit with a sustainable development philosophy. To determine the conditions of this revolution, it is useful to analyse the energy systems from the needs to the resources, in a historical, philosophical and technical manner. Starting from this analysis, this book explores the possibilities to build the transition towards this new energy revolution. (J.S.)

Considerations of digital phase modulation for narrowband satellite mobile communication

Science.gov (United States)

Grythe, Knut

1990-01-01

The Inmarsat-M system for mobile satellite communication is specified as a frequency division multiple access (FDMA) system, applying Offset Quadrature Phase Shift Keying (QPSK) for transmitting 8 kbit/sec in 10 kHz user channel bandwidth. We consider Digital Phase Modulation (DPM) as an alternative modulation format for INMARSAT-M. DPM is similar to Continuous Phase Modulation (CPM) except that DPM has a finite memory in the premodular filter with a continuous varying modulation index. It is shown that DPM with 64 states in the VA obtains a lower bit error rate (BER). Results for a 5 kHz system, with the same 8 kbit/sec transmitted bitstream, is also presented.

French revolution or industrial revolution?

DEFF Research Database (Denmark)

Weisdorf, Paul R. Sharp Jacob L.; Weisdorf, Jacob Louis

2012-01-01

in London and Paris in the centuries leading up to 1800. Whilst in London, building workers were facing low and stable consumer prices over the period, leaving plenty of scope for a demand-driven consumer revolution (in particular after 1650), their Parisian counterparts had to engage in a year-long grind...

Representing revolution: icons of industrialization.

Science.gov (United States)

Fara, Patricia

2006-03-01

Appreciating pictures entails a consideration not only of the people, objects and landscape that their artists have chosen to portray, but also an imagining of what has been excluded. The term 'Industrial Revolution' has been given multiple meanings, and this article (part of the Science in the Industrial Revolution series) explores some of these by exposing the messages concealed inside some of the most enduring images of the Revolution.

Colour revolutions: criminal-legal aspect

Directory of Open Access Journals (Sweden)

Sergey Alekseyevich Gordeychik

2015-03-01

Full Text Available Objective basing on the analysis of colour revolution technologies in different countries to formulate propositions for improving criminal legislation aimed at counteraction against this phenomenon. Methods general scientific induction deduction analysis synthesis and specific scientific formaljuridical and comparativelegal. Results using the results of colour revolutionsrsquo research carried out by political scientists the author evaluates the character and level of public danger of colour revolutions. The author states that the colour revolutions threaten the normal existence of the country or several countries. The conclusion is made that the colour revolutions must be counteracted by criminallegal means. The article states the absence of norms in the existing criminal legislation which would impose criminal liability on organizers incendiaries and participants of colour revolutions. It is proposed to supplement the existing criminal law with the norm stipulating the liability for such deeds and to insert this norm into Art. 34 ldquoCrimes against peace and security of humanityrdquo thus equating organization preparation and implementing colour revolutions with planning preparation launching and conducting an aggressive war Art. 353 of the Russian Criminal Code. Scientific novelty basing on the existing legal norms modern politological and juridical scientific literature a conclusion is made that the colour revolutions are based on the abuse of law. This allows the organizers of colour revolutions to legally prepare and implement the subversion of undesirable political regimes. The author formulates proposals for supplementing the criminal legislation. Practical value the materials and conclusions of the article can be used in lawmaking activity when elaborating the drafts of legal acts for changing and supplementing the Russian Criminal Code for research activity when preparing monographs and dissertations tutorials and articles when

Intelligent hearing aids: the next revolution.

Science.gov (United States)

Tao Zhang; Mustiere, Fred; Micheyl, Christophe

2016-08-01

The first revolution in hearing aids came from nonlinear amplification, which allows better compensation for both soft and loud sounds. The second revolution stemmed from the introduction of digital signal processing, which allows better programmability and more sophisticated algorithms. The third revolution in hearing aids is wireless, which allows seamless connectivity between a pair of hearing aids and with more and more external devices. Each revolution has fundamentally transformed hearing aids and pushed the entire industry forward significantly. Machine learning has received significant attention in recent years and has been applied in many other industries, e.g., robotics, speech recognition, genetics, and crowdsourcing. We argue that the next revolution in hearing aids is machine intelligence. In fact, this revolution is already quietly happening. We will review the development in at least three major areas: applications of machine learning in speech enhancement; applications of machine learning in individualization and customization of signal processing algorithms; applications of machine learning in improving the efficiency and effectiveness of clinical tests. With the advent of the internet of things, the above developments will accelerate. This revolution will bring patient satisfactions to a new level that has never been seen before.

Global-scale Observations of the Limb and Disk (GOLD) Mission: Science from Geostationary Orbit on-board a Commercial Communications Satellite

Science.gov (United States)

Eastes, R.; Deaver, T.; Krywonos, A.; Lankton, M. R.; McClintock, W. E.; Pang, R.

2011-12-01

Geostationary orbits are ideal for many science investigations of the Earth system on global scales. These orbits allow continuous observations of the same geographic region, enabling spatial and temporal changes to be distinguished and eliminating the ambiguity inherent to observations from low Earth orbit (LEO). Just as observations from geostationary orbit have revolutionized our understanding of changes in the troposphere, they will dramatically improve our understanding of the space environment at higher altitudes. However, geostationary orbits are infrequently used for science missions because of high costs. Geostationary satellites are large, typically weighing tons. Consequently, devoting an entire satellite to a science mission requires a large financial commitment, both for the spacecraft itself and for sufficient science instrumentation to justify a dedicated spacecraft. Furthermore, the small number of geostationary satellites produced for scientific missions increases the costs of each satellite. For these reasons, it is attractive to consider flying scientific instruments on satellites operated by commercial companies, some of whom have fleets of ~40 satellites. However, scientists' lack of understanding of the capabilities of commercial spacecraft as well as commercial companies' concerns about risks to their primary mission have impeded the cooperation necessary for the shared use of a spacecraft. Working with a commercial partner, the GOLD mission has successfully overcome these issues. Our experience indicates that there are numerous benefits to flying on commercial communications satellites (e.g., it is possible to downlink large amounts of data) and the costs are low if the experimental requirements adequately match the capabilities and available resources of the host spacecraft. Consequently, affordable access to geostationary orbit aboard a communications satellite now appears possible for science payloads.

The non-Euclidean revolution

CERN Document Server

Trudeau, Richard J

1986-01-01

How unique and definitive is Euclidean geometry in describing the "real" space in which we live? Richard Trudeau confronts the fundamental question of truth and its representation through mathematical models in The Non-Euclidean Revolution. First, the author analyzes geometry in its historical and philosophical setting; second, he examines a revolution every bit as significant as the Copernican revolution in astronomy and the Darwinian revolution in biology; third, on the most speculative level, he questions the possibility of absolute knowledge of the world. Trudeau writes in a lively, entertaining, and highly accessible style. His book provides one of the most stimulating and personal presentations of a struggle with the nature of truth in mathematics and the physical world. A portion of the book won the Pólya Prize, a distinguished award from the Mathematical Association of America. "Trudeau meets the challenge of reaching a broad audience in clever ways...(The book) is a good addition to our literature o...

GEO satellite markets and functions : Quarterly Launch Report : special report

Science.gov (United States)

1996-01-01

The information revolution has transformed telecommunication markets. The explosive demand for global communication has spawned accelerating technical innovation and fierce competition for telecommunication revenues. Deregulation of telecommunication...

The Meanings of 'Bourgeois Revolution': Conceptualizing the French Revolution

DEFF Research Database (Denmark)

Nygaard, Bertel

2007-01-01

Through an analysis of Marx’s writings on the French Revolution of 1789, the concept ‘bourgeois revolution’ can be shown to contain a much richer potential than the simplistic and widely rejected ‘orthodox’ notion of a capitalist bourgeoisie as a social agent with a fully developed class consciou......Through an analysis of Marx’s writings on the French Revolution of 1789, the concept ‘bourgeois revolution’ can be shown to contain a much richer potential than the simplistic and widely rejected ‘orthodox’ notion of a capitalist bourgeoisie as a social agent with a fully developed class...

Advanced Communication Technology Satellite (ACTS) multibeam antenna analysis and experiment

Science.gov (United States)

Acosta, Roberto J.; Lagin, Alan R.; Larko, Jeffrey M.; Narvaez, Adabelle

1992-01-01

One of the most important aspects of a satellite communication system design is the accurate estimation of antenna performance degradation. Pointing error, end coverage gain, peak gain degradation, etc. are the main concerns. The thermal or dynamic distortions of a reflector antenna structural system can affect the far-field antenna power distribution in a least four ways. (1) The antenna gain is reduced; (2) the main lobe of the antenna can be mispointed thus shifting the destination of the delivered power away from the desired locations; (3) the main lobe of the antenna pattern can be broadened, thus spreading the RF power over a larger area than desired; and (4) the antenna pattern sidelobes can increase, thus increasing the chances of interference among adjacent beams of multiple beam antenna system or with antenna beams of other satellites. The in-house developed NASA Lewis Research Center thermal/structural/RF analysis program was designed to accurately simulate the ACTS in-orbit thermal environment and predict the RF antenna performance. The program combines well establish computer programs (TRASYS, SINDA and NASTAN) with a dual reflector-physical optics RF analysis program. The ACTS multibeam antenna configuration is analyzed and several thermal cases are presented and compared with measurements (pre-flight).

Plan of Time Management of Satellite Positioning System using Quasi-zenith Satellite

Science.gov (United States)

Takahashi, Yasuhiro; Fujieda, Miho; Amagai, Jun; Yokota, Shoichiro; Kimura, Kazuhiro; Ito, Hiroyuki; Hama, Shin'ichi; Morikawa, Takao; Kawano, Isao; Kogure, Satoshi

The Quasi-Zenith satellites System (QZSS) is developed as an integrated satellite service system of communication, broadcasting and positioning for mobile users in specified regions of Japan from high elevation angle. Purposes of the satellite positioning system using Quasi-Zenith satellite (QZS) are to complement and augment the GPS. The national institutes concerned have been developing the positioning system using QZS since 2003 and will carry out experiments and researches in three years after the launch. In this system, National Institute of Information and Communications Technology (NICT) is mainly in charge of timing system for the satellite positioning system using QZS, such as onboard hydrogen maser atomic clock and precise time management system of the QZSS. We started to develop the engineering model of the time management system for the QZSS. The time management system for the QZSS will be used to compare time differences between QZS and earth station as well as to compare between three onboard atomic clocks. This paper introduces time management of satellite positioning system using the QZSS.

47 CFR 25.143 - Licensing provisions for the 1.6/2.4 GHz mobile-satellite service and 2 GHz mobile-satellite...

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Licensing provisions for the 1.6/2.4 GHz mobile-satellite service and 2 GHz mobile-satellite service. 25.143 Section 25.143 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses...

Telelibrary: Library Services via Satellite.

Science.gov (United States)

Liu, Rosa

1979-01-01

Investigates the provision of library services via satellite, explains briefly the operation and advantages of communication satellites, and discusses the various telecommunications equipment and services which, when coupled with satellite transmission, will enhance library activities. Demand trend projections for telecommunications services…

Toward the Public Dividend: A Report on Satellite Telecommunications and the Public Interest Satellite Association.

Science.gov (United States)

McGraw, Walter

This report points out that the communications satellite appears to be on its way to becoming one of the most dominant and controlling technologies of our time, and this requires that a new evaluation be made of our entire communications process. The first section of the report discusses many aspects of the history of satellites, including the…

Study of Education Satellite Communication Demonstration. Third Quarterly Progress Report. Report of Activities and Accomplishments January 11, 1975 to April 10, 1975.

Science.gov (United States)

Syracuse Univ. Research Corp., NY. Educational Policy Research Center.

A report on the Education Satellite Communication Demonstration (ESCD) describes activities of the evaluators during the first quarter of 1975, including staff trips and site visits and activities of various staff members. A calendar of future events in satellites, telecommunications, and education is included, with revision on dates and new…

Particle Filtering Equalization Method for a Satellite Communication Channel

Directory of Open Access Journals (Sweden)

Amblard Pierre-Olivier

2004-01-01

Full Text Available We propose the use of particle filtering techniques and Monte Carlo methods to tackle the in-line and blind equalization of a satellite communication channel. The main difficulties encountered are the nonlinear distortions caused by the amplifier stage in the satellite. Several processing methods manage to take into account these nonlinearities but they require the knowledge of a training input sequence for updating the equalizer parameters. Blind equalization methods also exist but they require a Volterra modelization of the system which is not suited for equalization purpose for the present model. The aim of the method proposed in the paper is also to blindly restore the emitted message. To reach this goal, a Bayesian point of view is adopted. Prior knowledge of the emitted symbols and of the nonlinear amplification model, as well as the information available from the received signal, is jointly used by considering the posterior distribution of the input sequence. Such a probability distribution is very difficult to study and thus motivates the implementation of Monte Carlo simulation methods. The presentation of the equalization method is cut into two parts. The first part solves the problem for a simplified model, focusing on the nonlinearities of the model. The second part deals with the complete model, using sampling approaches previously developed. The algorithms are illustrated and their performance is evaluated using bit error rate versus signal-to-noise ratio curves.

Toilet revolution in China.

Science.gov (United States)

Cheng, Shikun; Li, Zifu; Uddin, Sayed Mohammad Nazim; Mang, Heinz-Peter; Zhou, Xiaoqin; Zhang, Jian; Zheng, Lei; Zhang, Lingling

2018-06-15

The wide-spread prevalence of unimproved sanitation technologies has been a major cause of concern for the environment and public health, and China is no exception to this. Towards the sanitation issue, toilet revolution has become a buzzword in China recently. This paper elaborates the backgrounds, connotations, and actions of the toilet revolution in China. The toilet revolution aims to create sanitation infrastructure and public services that work for everyone and that turn waste into value. Opportunities for implementing the toilet revolution include: fulfilling Millennium Development Goals and new Sustainable Development Goals; government support at all levels for popularizing sanitary toilet; environmental protection to alleviate wastewater pollution; resource recovery from human waste and disease prevention for health and wellbeing improvement. Meanwhile, the challenges faced are: insufficient funding and policy support, regional imbalance and lagging approval processes, weak sanitary awareness and low acceptance of new toilets, lack of R&D and service system. The toilet revolution requires a concerted effort from many governmental departments. It needs to address not only technology implementation, but also social acceptance, economic affordability, maintenance issues and, increasingly, gender considerations. Aligned with the ecological sanitation principles, it calls for understanding issues across the entire sanitation service chain. Public-private partnership is also recommended to absorb private capital to make up the lack of funds, as well as arouse the enthusiasm of the public. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Izviđanje satelitskih komunikacija u funkciji savremenih operacija / Reconnaissance of satellite communications in contemporary operations

Directory of Open Access Journals (Sweden)

Slaviša Đukanović

2004-05-01

Full Text Available Raspoloživi vojni resursi u bilo kojoj kategoriji nisu kritični u mirnodopskom periodu, jer se dimenzionišu za ratno naprezanje određenog nivoa. Međutim, u uslovima izvođenja borbenih dejstava postoje ekstremi u zahtevima za angažovanjem, koje sistemi ne mogu da izdrže. Takav slučaj je kod satelitskih komunikacija. U radu su prezentovane taktičko-tehničke i dinamičke osobine komercijalnih (INMARSAT, INTELSAT, IRIDIJUM.. i vojnih (DSCS, FLEET-SATCOM, NATO, SKYNET.. satelitskih sistema, koje su bitne za uspešno vođenje elektronskog rata. Takođe, dat je pregled raspoloživih korisničkih servisa savremenih satelitskih sistema (Internet provajding video-konferencije, prenos multimedija uživo, fax, e-mail, voice. Nova generacija širokopojasnih satelita, koja se pušta u rad tokom ove godine omogućiće globalni roming navedenih servisa INMARSAT satelitskom sistemu koji se sve češće koristi u vojne svrhe. U perspektivi je da se usluge koje pružaju satelitski sistemi (komunikacioni, navigacioni, izviđački meteorološki.. stave na raspolaganje nižim taktičkim jedinicama vazduhoplovima, pa čak i svakom vojniku ponaosob. Poznavanje satelitskih sistema potencijalnog agresora pruža mogućnost da se odrede ranjive tačke samog sistema sa aspekta izviđanja i ometanja. / Available military resources in any category are not critical in peace since they are tailored for military use under extreme conditions. However, some systems such as satellite communications, cannot meet extreme requirements during combat actions. The paper presents tactical and technical specifications and dynamic characteristics of commercial (INMARSAT. INTELSAT, IRIDIJUM,.. and military (DSCS, FLEET-SATCOM, NATO, SKYNET,.. satellite systems which are important for electronic warfare. The paper also gives available user services of contemporary satellite systems (Internet providing, videoconferences, live multi-media, fax, e-mail, voice. A new generation of

Satellite communication on pipeline supervision using TCP-IP Protocol; Comunicacao via satelite na supervisao de dutos usando o protocolo TCP-IP

Energy Technology Data Exchange (ETDEWEB)

Silva, Agliberto Pessoa da [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil); Brunette, Sergio Henrique de Moraes

2003-07-01

Bit transparent type or X-25 protocols have been used in VSAT satellite communication by PETROBRAS pipeline Supervisory Control and Data Acquisition System (SCADA) as access protocol. Both solutions have inconveniences. By the first one, difficulties exist for analysis and diagnosis of connection flaws, and therefore, for a ready identification by the system management stations of abnormality location. On the other hand, the usage of the X-25 brings an additional over-head in the communication since this is not an available option in most of the equipment that compose the SCADA. The access to VSAT through Ethernet, in the opposite, makes available all networks management tools of the TCP/IP platform and it allows a direct connection to the field devices, since the main models of the several makers of Programmable Controllers and Remote Terminal Units have Ethernet port. An additional earnings is the possibility of standardization that this solution allows. This paper describes a series of communication tests between two Programmable Controllers communicating through the satellite, using a protocol over Ethernet/TCP/IP. (author)

Communication schemes for olfar's inter-satellite links

NARCIS (Netherlands)

Budianu, A.; Willink-Castro, T.J.; Meijerink, Arjan; Bentum, Marinus Jan

2012-01-01

The Orbiting Low Frequency Array for Radio astronomy(OLFAR) project is aimed at developing a radio telescope in space sensitive for the 0.3–30 MHz range by using a swarm of more than 50 identical nano-satellites. The satellites will form a very large aperture, capable of capturing very weak

The Industrial Revolution: A Misnomer.

Science.gov (United States)

Cameron, Rondo

1982-01-01

Argues that the British industrial revolution was in no sense inevitable and scarcely deserves the term "revolution." Examined are the characteristics which the British shared with other Europeans and ways in which they were distinctive that enabled them to become the first industrial nation. (RM)

The neosexual revolution.

Science.gov (United States)

Sigusch, V

1998-08-01

The affluent societies of the Western world have witnessed a tremendous cultural and social transformation of sexuality during the 1980s and 1990s, a process I refer to as the neosexual revolution. Up to now, this recoding and reassessment of sexuality has proceeded rather slowly and quietly. Yet both its real and its symbolic effects may indeed be more consequential than those brought about in the course of the rapid, noisy sexual revolution of the 1960s and 1970s. The neosexual revolution is dismantling the old patterns of sexuality and reassembling them anew. In the process, dimensions, intimate relationships, preferences, and sexual fragments emerge, many of which had been submerged, were unnamed, or simply did not exist before. In general, sexuality has lost much of its symbolic meaning as a cultural phenomenon. Sexuality is no longer the great metaphor for pleasure and happiness, nor is it so greatly overestimated as it was during the sexual revolution. It is now widely taken for granted, much like egotism or motility. Whereas sex was once mystified in a positive sense--as ecstasy and transgression, it has now taken on a negative mystification characterized by abuse, violence, and deadly infection. While the old sexuality was based primarily upon sexual instinct, orgasm, and the heterosexual couple, neosexualities revolve predominantly around gender difference, thrills, self-gratification, and prosthetic substitution. From the vast number of interrelated processes from which neosexualities emerge, three empirically observable phenomena have been selected for discussion here: the dissociation of the sexual sphere, the dispersion of sexual fragments, and the diversification of intimate relationships. These processes go hand in hand with the commercialization and banalization of sexuality. They are looked upon as being controlled individually through the mechanisms of a fundamentally egotistical consensus morality. In conformity with the general principles at

Information Technology and the Third Industrial Revolution.

Science.gov (United States)

Fitzsimmons, Joe

1994-01-01

Discusses the so-called third industrial revolution, or the information revolution. Topics addressed include the progression of the revolution in the U.S. economy, in Europe, and in Third World countries; the empowering technologies, including digital switches, optical fiber, semiconductors, CD-ROM, networks, and combining technologies; and future…

Revolutions that made the earth

CERN Document Server

Lenton, Tim

2013-01-01

The Earth that sustains us today was born out of a few remarkable, near-catastrophic revolutions, started by biological innovations and marked by global environmental consequences. The revolutions have certain features in common, such as an increase in the complexity, energy utilization, and information processing capabilities of life. This book describes these revolutions, showing the fundamental interdependence of the evolution of life and its non-living environment. We would not exist unless these upheavals had led eventually to 'successful' outcomes - meaning that after each one, at length, a new stable world emerged. The current planet-reshaping activities of our species may be the start of another great Earth system revolution, but there is no guarantee that this one will be successful. This book explains what a successful transition through it might look like, if we are wise enough to steer such a course. This book places humanity in context as part of the Earth system, using a new scientific synthe...

Full Service ISDN Satellite (FSIS) network model for advanced ISDN satellite design and experiments

Science.gov (United States)

Pepin, Gerard R.

1992-01-01

The Full Service Integrated Services Digital Network (FSIS) network model for advanced satellite designs describes a model suitable for discrete event simulations. A top down model design uses the Advanced Communications Technology Satellite (ACTS) as its basis. The ACTS and the Interim Service ISDN Satellite (ISIS) perform ISDN protocol analyses and switching decisions in the terrestrial domain, whereas FSIS makes all its analyses and decisions on-board the ISDN satellite.

Conceptual design of a synchronous Mars telecommunications satellite

Science.gov (United States)

Badi, Deborah M.; Farmer, Jeffrey T.; Garn, Paul A.; Martin, Gary L.

1989-01-01

Future missions to Mars will require a communications system to link activities on the Martian surface with each other and with mission controllers on Earth. A conceptual design is presented for an aerosynchronous communications satellite to provide these links. The satellite provides the capability for voice, data/command, and video transmissions. The mission scenario assumed for the design is described, and a description of a single aerosynchronous satellite is explained. A viable spacecraft design is then presented. Communication band selection and channel allocation are discussed. The communications system conceptual design is presented along with the trades used in sizing each of the required antennas. Also, the analyses used to develop the supporting subsystem designs are described as is the communications impact on each subsystem design.

Satellite data transferring subsystem based on system 'Materik'

International Nuclear Information System (INIS)

Belogub, V.P.; Kal'schikov, I.B.; Kirillov, Yu.K.; Kulikov, V.N.; Shumov, A.N.

1998-01-01

One of the most important indicators of successful function of the International Monitoring System is existence of highly reliable communication channels providing transfer data from observation points in a real time scales. Up to present, the most communication channels were provided with existing VF-channels (Voice Frequency) that are relatively low-speedy in transfer process (4.8-9.6 kbit/sec.). In addition, reliability of the channels is insufficient because of many retransmission points. In connection with it, the special control service of MD RF decided to improve the information transfer system (ITS) installed between the observation point and National Data Center (Dubna-city). The improvement of the ITS comprises replacement of wire lines of VF-channels with satellite ones within the framework of the computer-aided satellite communication system (CASCS) M aterik . Besides it was considered to be expedient that the satellite system of data transfer from NPP to the Crisis Center of 'ROSENERGOATOM' Concern would be combined with CASCS M aterik , using the facilities of the Central Earth Station of Satellite Communication (CESSC) in Dubna. Such approach to the creation of Satellite communication has advantages in solution of radiation safety and global monitoring issues

Annual view (1999) - aeronautic relation/space relation. Space relation - communication/broadcasting/engineering test satellite; Nenkan tenbo (1999) koku kankei uchu kankei. Tsushin, hoso, gijutsu shiken eisei kanren

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-05

To cope with the increasing communication demand, the R and D of engineering test satellite V III are being conducted being aimed at developing a technology of the world's largest class geostationary satellite. As to the large developing rectenna, a model for development was manufactured and is now in test. In August and September 1999, the system combustion test of complete two-liquid chemical propulsion system was carried out at Ishikawajima-Harima Heavy Industries. The R and D of the data relay technology satellite are being conducted for the purpose of conducting orbital demonstrative tests to improve the data relay functional performance of satellite and to spread the data relay range. The engineering test satellite VII was developed to study the space rendezvous/docking technology and the basic technology of space use robot. It was launched in November 1997 and got a lot of valuable data. The operation of satellite has been continued for the acquisition of data such as secular changes of satellite equipment. About the communication broadcasting satellite, experiments and functional tests were finished, and the operation was stopped in August 1999. (NEDO)

Satellite transmission of oceanographic data

Digital Repository Service at National Institute of Oceanography (India)

Desa, E.S.; Desai, R.G.P.; DeSa, E.J.

Oceanographic data collected on a research vessel has been transmitted to a shore laboratory using the INMARSAT maritime satellite The system configuration used, consisted of Satellite Communication Terminals interfaced to desk top computers...

Challenges of communication system during emergency disaster ...

African Journals Online (AJOL)

pc

2017-10-05

Oct 5, 2017 ... 3.2.3.Satellite-Based Communication. Satellite-based communication is another alternative for communication in the event of disaster. Japan, United States of America and Russia are the countries that have utilised the system to disseminate emergency messages during previous disasters. Satellite-based.

The Nanotechnology R(evolution)

OpenAIRE

Tahan, Charles

2006-01-01

Nanotechnology as a social concept and investment focal point has drawn much attention. Here we consider the place of nanotechnology in the second great technological revolution of mankind that began some 200 years ago. The so-called nanotechnology revolution represents both a continuation of prior science and technology trends and a re-awakening to the benefits of significant investment in fundamental research. We consider the role the military might play in the development of nanotechnology...

History of Satellite TV Broadcasting and Satellite Broadcasting Market in Turkey

Directory of Open Access Journals (Sweden)

Mihalis KUYUCU

2015-09-01

Full Text Available The present study analyses the satellite broadcasting that is the first important development that emerged as a result of digitalization in communication technologies and its reflections in Turkey. As the first milestone in the globalization of television broadcasting, satellite broadcasting provided substantial contribution towards the development of the media. Satellite bro adcasting both increased the broadcasting quality and geographical coverage of the television media. A conceptual study was carried out in the first part of the study in connection with the history of satellite broadcasting in Turkey and across the world. In the research part of the study, an analysis was performed on 160 television channels that broadcast in Turkey via Turksat Satellite. Economic structure of the television channels broadcasting in Turkey via satellite was studied and an analysis was perfo rmed on the operational structure of the channels. As a result of the study, it was emphasized that the television channels broadcasting via satellite platform also use other platforms for the purpose of spreading their broadcasts and television channel ow ners make investments in different branches of the media, too. Capital owners invest in different business areas other than the media although television channels broadcasting via Turksat mostly focus on thematic broadcasting and make effort to generate ec onomic income from advertisements. Delays are encountered in the course of the convergence between the new media and television channels that broadcast only from the satellite platform and such television channels experience more economic problems than the other channels. New media and many TV broadcasting platforms emerged as a result of the developments in the communication technologies. In television broadcasting, satellite platform is not an effective platform on its own. Channels make effort to reach t o more people by using other platforms in addition to

Laser experiments in light cloudiness with the geostationary satellite ARTEMIS

Science.gov (United States)

Kuzkov, V.; Kuzkov, S.; Sodnik, Z.

2016-08-01

The geostationary satellite ARTEMIS was launched in July 2001. The satellite is equipped with a laser communication terminal, which was used for the world's first inter-satellite laser communication link between ARTEMIS and the low earth orbit satellite SPOT-4. Ground-to-space laser communication experiments were also conducted under various atmospheric conditions involving ESA's optical ground station. With a rapidly increasing volume of information transferred by geostationary satellites, there is a rising demand for high-speed data links between ground stations and satellites. For ground-to-space laser communications there are a number of important design parameters that need to be addressed, among them, the influence of atmospheric turbulence in different atmospheric conditions and link geometries. The Main Astronomical Observatory of NAS of Ukraine developed a precise computer tracking system for its 0.7 m AZT-2 telescope and a compact laser communication package LACES (Laser Atmosphere and Communication experiments with Satellites) for laser communication experiments with geostationary satellites. The specially developed software allows computerized tracking of the satellites using their orbital data. A number of laser experiments between MAO and ARTEMIS were conducted in partial cloudiness with some amount of laser light observed through clouds. Such conditions caused high break-up (splitting) of images from the laser beacon of ARTEMIS. One possible explanation is Raman scattering of photons on molecules of a water vapor in the atmosphere. Raman scattering causes a shift in a wavelength of the photons.In addition, a different value for the refraction index appears in the direction of the meridian for the wavelength-shifted photons. This is similar to the anomalous atmospheric refraction that appears at low angular altitudes above the horizon. We have also estimated the atmospheric attenuation and the influence of atmospheric turbulence on observed results

Revolution, modernity, and the potential of narratives

DEFF Research Database (Denmark)

Eriksson, Birgit

2013-01-01

The article investigates the impact of the French Revolution on Goethe’s narrative works in the mid-1790s. I argue that the reductive interpretation of Goethe’s attitude to the Revolution as distant and reluctant ignores the formal and thematic impact of the Revolution on his prose works. Similarly......, we lose important perspectives when reducing German intellectual life of the late eighteenth century to apolitical inwardness. The Revolution had an impact, also in the German context, and Goethe’s literary works were significantly affected by it. Working in various literary genres, he investigated...... and experimented with some of the fundamental challenges of the Revolution and the modern era, especially those regarding self-determination, community, and the nexus between individual and shared history. Following a brief sketch of how these issues looked from a German perspective, I will focus on Goethe’s...

Cooperative and cognitive satellite systems

CERN Document Server

Chatzinotas, Symeon; De Gaudenzi, Riccardo

2015-01-01

Cooperative and Cognitive Satellite Systems provides a solid overview of the current research in the field of cooperative and cognitive satellite systems, helping users understand how to incorporate state-of-the-art communication techniques in innovative satellite network architectures to enable the next generation of satellite systems. The book is edited and written by top researchers and practitioners in the field, providing a comprehensive explanation of current research that allows users to discover future technologies and their applications, integrate satellite and terrestrial systems

Japan's telecommunications - New initiatives in space communications

Science.gov (United States)

Iida, T.

1992-04-01

Despite recent advances in optical transmission technology, intensive R&D work in the field of satellite communications is now being undertaken in Japan. It is believed that satellites offer advantages in several important areas, including wide coverage broadcasting, immediacy of service, suitability for the implementation of HDTV, and advantages in disaster communications and other social services. Here, some experimental projects in the field of satellite communications planned in Japan for the 1990s are summarized. In particular, attention is given to broadcast satellite development, intersatellite links, advanced mobile communication concepts, large antenna assembly experiment, small satellite R&D, and Pan-Pacific information network experiment.

Using Satellite Technology to Increase Professional Communications Among Teachers: a Report of Experiments Conducted by the National Education Association.

Science.gov (United States)

National Education Association, Washington, DC. Div. of Instruction and Professional Development.

The National Education Association (NEA) in conjunction with the National Aeronautics and Space Administration, the National Library of Medicine, The Alaska Broadcasting Commission, and the Pacific PEACESAT Network, conducted four satellite experiments designed to improve professional communication among teachers. These programs were the Satellite…

Design and Evaluation of 10-Gbps Inter-satellite Optical Wireless Communication Link for Improved Performance

Science.gov (United States)

Gupta, Amit; Nagpal, Shaina

2017-05-01

Inter-satellite optical wireless communication (IsOWC) systems can be chosen over existing microwave satellite systems for deploying in space in the future due to their high bandwidth, small size, light weight, low power and low cost. However, the IsOWC system suffers from various attenuations due to weather conditions, turbulence or scintillations which limit its performance and decreases its availability. So, in order to improve the performance, IsOWC system using directly modulated laser source is proposed in this work. The system is designed and evaluated to be suitable for high data rate transmissions up to 10 Gbps. The performance of the system is investigated in order to reduce the cost and complexity of link and improving the quality of information signal. Further the proposed IsOWC system is analysed using BER analyser, power meter and oscilloscope Visualizer.

Revolutions in astronomy, physics and cosmology

International Nuclear Information System (INIS)

Idlis, G.M.

1985-01-01

As consecutive turning-points in the development of natural science four global natural science revolutions (Aristotelian, Newton, Einstein and post-Einstein) are marked out and briefly outlined. Each of them simultaneously occurred in astronomy, physics and cosmology and was accompanied by radical changes of cosmological representations. These changes had quite a regular consecutive character and represented necessary steps in turn along the natural way of further elimination of ego centrism from cosmology. The first (Aristotelian) revolution turnes out a peculiar prototype of all three subsequent revolutions in astronomy, physics and cosmology. The special more detailed analysis of this revolution in this monograph allows one to tie together antique and modern phases of the science development including corresponding representations on fundamental structural elements of the matter. Besides the review of literature data the monograph comprises a series of author's scientific results

Proceedings of the Twentieth NASA Propagation Experimenters Meeting (NAPEX XX) and the Advanced Communications Technology Satellite (ACTS) Propagation Studies Miniworkshop

Science.gov (United States)

Golshan, Nassar (Editor)

1996-01-01

The NASA Propagation Experimenters (NAPEX) Meeting and associated Advanced Communications Technology Satellite (ACTS) Propagation Studies Miniworkshop convene yearly to discuss studies supported by the NASA Propagation Program. Representatives from the satellite communications (satcom)industry, academia, and government with an interest in space-ground radio wave propagation have peer discussion of work in progress, disseminate propagation results, and interact with the satcom industry. NAPEX XX, in Fairbanks, Alaska, June 4-5, 1996, had three sessions: (1) "ACTS Propagation Study: Background, Objectives, and Outcomes," covered results from thirteen station-years of Ka-band experiments; (2) "Propagation Studies for Mobile and Personal Satellite Applications," provided the latest developments in measurement, modeling, and dissemination of propagation phenomena of interest to the mobile, personal, and aeronautical satcom industry; and (3)"Propagation Research Topics," covered a range of topics including space/ground optical propagation experiments, propagation databases, the NASA Propagation Web Site, and revision plans for the NASA propagation effects handbooks. The ACTS Miniworkshop, June 6, 1996, covered ACTS status, engineering support for ACTS propagation terminals, and the ACTS Propagation Data Center. A plenary session made specific recommendations for the future direction of the program.

Satellite outreach in Asia and the Pacific.

Science.gov (United States)

1977-01-01

Communication by satellite is rapidly changing information exchange in Asia, especially for rural areas. The integrated education planned for satellite networks includes family planning as part of general development. A series of conferences has already been held successfully via satellite for family planning associations who are members of the East and Southeast Asia and Oceania Region of the International Planned Parenthood Federation. These included a conference on nursing training. In India the Satellite Instructional Television Experiment (SITE) made history during its 1-year trial. By 1981 the entire nation is to be linked by satellite. The question is whether the television education will truly change rural life or whether it will become merely a diversion. In Indonesia, satellites were chosen as the fastest way to obtain interisland communication. The Domsat system links the entire 13,000-island archipelago and is already being used for emergency communications. The system, which was developed in 1 1/2 years by the Hughes Aircraft Corporation will be used for teaching basic health, hygiene, and family planning. It will be several years before Domsat is fully operational, but it bears watching.

The future of mathematical communication. Final technical report

Energy Technology Data Exchange (ETDEWEB)

Christy, J.

1994-12-31

One of the first fruits of cooperation with LBL was the use of the MBone (Multi-Cast Backbone) to broadcast the Conference on the Future of Mathematical Communication, held at MSRI November 30--December 3, 1994. Late last fall, MSRI brought together more than 150 mathematicians, librarians, software developers, representatives of scholarly societies, and both commercial and not-for-profit publishers to discuss the revolution in scholarly communication brought about by digital technology. The conference was funded by the Department of Energy, the National Science Foundation, and the Paul and Gabriella Rosenbaum Foundation. It focused on the impact of the technological revolution on mathematics, but necessarily included issues of a much wider scope. There were talks on electronic publishing, collaboration across the Internet, economic and intellectual property issues, and various new technologies which promise to carry the revolution forward. There were panel discussions of electronic documents in mathematics, the unique nature of electronic journals, technological tools, and the role of scholarly societies. There were focus groups on Developing Countries, K-12 Education, Libraries, and Te{sub X}. The meeting also embodied the promises of the revolution; it was multicast over the MBone channel of the Internet to hundreds of sites around the world and much information on the conference will be available on their World Wide Web server at the URL http://www.msri.org/fmc. The authors have received many comments about the meeting indicating that it has had a profound impact on how the community thinks about how scientists can communicate and make their work public.

Three Views of the Information Revolution.

Science.gov (United States)

McHale, Magda Cordell; Harris, David A.

1983-01-01

Cultural institutions and attitudes are being reshaped and often disrupted without warning or intention by the information revolution. Different socio-cultural visions of the information revolution among scholars in France, Japan, and the third world are described. (Author/RM)

Proceedings of the Fifth International Mobile Satellite Conference 1997

Science.gov (United States)

Jedrey, T. (Compiler); Rigley, J. (Compiler); Anderson, Louise (Editor)

1997-01-01

Satellite-based mobile communications systems provide voice and data communications to users over a vast geographic area. The users may communicate via mobile or hand-held terminals, which may also provide access to terrestrial communications services. While previous International Mobile Satellite Conferences have concentrated on technical advances and the increasing worldwide commercial activities, this conference focuses on the next generation of mobile satellite services. The approximately 80 papers included here cover sessions in the following areas: networking and protocols; code division multiple access technologies; demand, economics and technology issues; current and planned systems; propagation; terminal technology; modulation and coding advances; spacecraft technology; advanced systems; and applications and experiments.

Mexico´s long revolutions

Directory of Open Access Journals (Sweden)

Petri Minkkinen

2011-06-01

Full Text Available México celebraba en el año 2010 el Bicentenario del empiezo de sus luchas de independencia y el Centenario de la Revolución Mexicana de 1910. Lo que no se celebra oficialmente es el proceso revolucionario contemporáneo, aunque sus ciertas fases han incluido entusiasmo por parte de diferentes actores sociales. En este artículo les ofrezco un análisis histórico de estos procesos revolucionarios como tres largas revoluciones de México. Además de eso, las explicaré dentro de un contexto histórico más amplio la transición desde un contexto histórico amplio eurocéntrico hacia un contexto histórico amplio no-eurocéntrico, que podemos entender también como la Primera Verdadera Revolución Mundial (PVRM. Empiezo con la explicación de este contexto histórico amplio. Continúo con el análisis del proceso de independencia desde 1810 así como la Revolución Mexicana desde 1910. Adelanto con la explicación de la tercera larga revolución mexicana, para la cual he seleccionado como el año del empiezo el 1988 y las elecciones presidenciales. Otros posibles años del empiezo podrían ser la represión del movimiento estudiantil en 1968 y la rebelión neozapatista desde 1994. En manera de conclusión se analiza como las largas revoluciones mexicanas están conectadas a las transiciones en la esfera del contexto histórico amplio.Palabras clave: México, revolución, largas revoluciones, Primera Verdadera Revolución Mundial (PVEM___________________________Abstract:Mexico celebrated in 2010 the Bicentenary of the beginning of its struggles of independence and the Centenary of the Mexican Revolution of 1910. What is not celebrated officially is the contemporary revolutionary process though some of its phases have included enthusiasm for the part of different social actors. In this article I offer you a historical analysis of these revolutionary processes as Mexico’s three long revolutions. Besides that I will explain them within the

The Industrial Revolution: An ERIC/ChESS Sample.

Science.gov (United States)

Pinhey, Laura A.

2000-01-01

Provides a list, from the ERIC database, of teaching materials and background information on the Industrial Revolution. Specific topics include life in Lowell (Massachusetts), the global impact of the Industrial Revolution, and England's Industrial Revolution. Offers directions for obtaining the full text of these materials. (CMK)

Mobile Communications within the Deepwater Lifelines

Science.gov (United States)

2013-12-13

Commission FDA United States Food and Drug Administration FFC Fleet Force Command FM Frequency Modulation GIG Global Information Grid GNSS Global...ago . . . Like a chrysalis, we’re emerging from the economy of the Industrial Revolution.” ―Ravitch, “Ronald Reagan Speech” The purpose of this...oceans are under satellite coverage capable of providing global information grid ( GIG ) connectivity? 6. What are the security concerns with using

Performance Analysis of an Enhanced PRMA-HS Protocol for LEO Satellite Communication

Institute of Scientific and Technical Information of China (English)

ZHUO Yong-ning; YAN Shao-hu; WU Shi-qi

2005-01-01

The packet reservation multiple access with hindering state (PRMA-HS) is a protocol suitable for LEO satellite mobile communication. Although working well with light system payload (amount of user terminals), the protocol imposes high channel congestion on system with heavy payload, thus degrades the system's quality of service. To controlling the channel congestion, a scheme of enhanced PRMA-HS protocol is proposed, which aims to reduce the collision of voice packets by adopting a mechanism of access control. Through theoretic analysis, the system's mathematic model is presented and the packet drop probability of the scheme is deduced. To testify the performance of the scheme, a simulation is performed and the results support our analysis.

The third energy revolution

International Nuclear Information System (INIS)

Lauvergeon, A.; Jamard, M.H.

2008-01-01

The first energy revolution was fueled by coal, the second by oil and electricity. The third energy revolution will be that of carbon-free energies, with nuclear power in the lead. For authors all available resources will be needed to satisfy the huge demand for energy shaping up for the future while preserving an increasingly fragile environment. Confronting these major challenges, they explain how reliable, carbon-free nuclear power has a real role to play in a more diversified energy mix. (A.L.B.)

A Novel Location-Awareness Method Using CubeSats for Locating the Spot Beam Emitters of Geostationary Communications Satellites

Directory of Open Access Journals (Sweden)

Weicai Yang

2018-01-01

Full Text Available As more spacecraft are launched into the Geostationary Earth Orbit (GEO belt, the possibility of fatal collisions or unnecessary interference between spacecraft increases. In this paper, a new location-awareness method that uses CubeSats is proposed to assist with radiofrequency (RF domain verification by means of awareness and identification of the positions of the spot beam emitters of communications satellites in geostationary orbit. By flying a CubeSat (or a constellation of CubeSats through the coverage area of a spot beam, the spot beam emitter’s position is identified and the spot beam’s pattern knowledge is characterized. The geometry, the equations of motion of the spacecraft, the measurement process, and the filtering equations in a location system are addressed with respect to the location methods investigated in this study. A realistic scenario in which a CubeSat receives signals from GEO communications satellites is simulated using the Systems Tool Kit (STK. The results of the simulation and the analysis presented in this study provide a thorough verification of the performance of the location-awareness method.

French Revolution or Industrial Revolution? A Note on the Contrasting Experiences of England and France up to 1800

OpenAIRE

Paul R. Sharp; Jacob L. Weisdorf

2011-01-01

At the end of the eighteenth century, England and France both underwent revolutions: France the French Revolution, England the industrial revolution. This note sheds new light on these contrasting experiences in the histories of England and France by looking at the evolution of real consumer prices in London and Paris in the centuries leading up to 1800. Whilst in London, building workers were facing low and stable consumer prices over the period, leaving plenty of scope for a demand-driven c...

Education and the Satellite: Possibilities for Saudi Arabia?

Science.gov (United States)

Al-Sharhan, Jamal

2000-01-01

Discussion of developments in satellite communications and educational applications focuses on the possibilities of adapting satellite technology for instruction in developing countries. Topics include satellite use in Australia and the United States; and recommendations for the adoption of satellite technology in Saudi Arabia. (Author/LRW)

Constructing Marxism: Karl Kautsky and the French Revolution

DEFF Research Database (Denmark)

Nygaard, Bertel

2009-01-01

Karl Kautsky's writings on the French Revolution were crucial to the construction not only of the Marxist interpretation of the Revolution, which was perhaps the most important reference point for the historiography of that event during the 20th century, but even of Marxism itself as a comprehens......Karl Kautsky's writings on the French Revolution were crucial to the construction not only of the Marxist interpretation of the Revolution, which was perhaps the most important reference point for the historiography of that event during the 20th century, but even of Marxism itself...

An introduction to optimal satellite range scheduling

CERN Document Server

Vázquez Álvarez, Antonio José

2015-01-01

The satellite range scheduling (SRS) problem, an important operations research problem in the aerospace industry consisting of allocating tasks among satellites and Earth-bound objects, is examined in this book. SRS principles and solutions are applicable to many areas, including: Satellite communications, where tasks are communication intervals between sets of satellites and ground stations Earth observation, where tasks are observations of spots on the Earth by satellites Sensor scheduling, where tasks are observations of satellites by sensors on the Earth. This self-contained monograph begins with a structured compendium of the problem and moves on to explain the optimal approach to the solution, which includes aspects from graph theory, set theory, game theory and belief networks. This book is accessible to students, professionals and researchers in a variety of fields, including: operations research, optimization, scheduling theory, dynamic programming and game theory. Taking account of the distributed, ...

Dissent, revolution and liberty beyond Earth

CERN Document Server

2016-01-01

This volume provides an in-depth discussion on the central question – how can people express and survive dissent and disagreement in confined habitats in space? The discussion is an important one because it could be that the systems of inter-dependence required to survive in space are so strong that dissent becomes impossible. John Locke originally said that people have a right to use revolution to overthrow a despotic regime. But if revolution causes violence and damage that causes depressurisation with the risk of killing many people, is it even permissible to have a revolution? How then are people to express their liberty or dissatisfaction with their rulers? The emergence of structures of dissent and disagreement is an essential part of the construction of a framework of liberty in space (revolution is just the extreme example) and thus the topic deserves in-depth and immediate attention. Even today, the way in which we assemble organisations and corporations for the government and private exploration o...

GAUSS Market Analysis for Integrated Satellite Communication and Navigation Location Based services

Science.gov (United States)

Di Fazio, Antonella; Dricot, Fabienne; Tata, Francesco

2003-07-01

The demand for mobile information services coupled with positioning technologies for delivering value- added services that depend on a user's location has rapidly increased during last years. In particular, services and applications related with improved mobility safety and transport efficiency look very attractive.Solutions for location services vary in respect of positioning accuracy and the technical infrastructure required, and the associated investment in terminals and networks. From the analysis of the state-of-the art, it comes that various technologies are currently available on the European market, while mobile industry is gearing up to launch a wide variety of location services like tracking, alarming and locating.Nevertheless, when addressing safety of life as well as security applications, severe hurdles have to be posed in the light of existing technologies. Existing navigation (e.g. GPS) and communication systems are not able to completely satisfy the needs and requirements of safety-of-life-critical applications. As a matter of fact, the GPS system's main weaknesses today is its lack of integrity, which means its inability to warn users of a malfunction in a reasonable time, while the other positioning techniques do not provide satisfactory accuracy as well, and terrestrial communication networks are not capable to cope with stringent requirement in terms of service reliability and coverage.In this context, GAUSS proposes an innovative satellite-based solution using novel technology and effective tools for addressing mobility challenges in a cost efficient manner, improving safety and effectiveness.GAUSS (Galileo And UMTS Synergetic System) is a Research and Technological Development project co- funded by European Commission, within the frame of the 5th IST Programme. The project lasted two years, and it was successfully completed in November 2002. GAUSS key concept is the integration of Satellite Navigation GNSS and UMTS communication technology, to

Cyber security with radio frequency interferences mitigation study for satellite systems

Science.gov (United States)

Wang, Gang; Wei, Sixiao; Chen, Genshe; Tian, Xin; Shen, Dan; Pham, Khanh; Nguyen, Tien M.; Blasch, Erik

2016-05-01

Satellite systems including the Global Navigation Satellite System (GNSS) and the satellite communications (SATCOM) system provide great convenience and utility to human life including emergency response, wide area efficient communications, and effective transportation. Elements of satellite systems incorporate technologies such as navigation with the global positioning system (GPS), satellite digital video broadcasting, and information transmission with a very small aperture terminal (VSAT), etc. The satellite systems importance is growing in prominence with end users' requirement for globally high data rate transmissions; the cost reduction of launching satellites; development of smaller sized satellites including cubesat, nanosat, picosat, and femtosat; and integrating internet services with satellite networks. However, with the promising benefits, challenges remain to fully develop secure and robust satellite systems with pervasive computing and communications. In this paper, we investigate both cyber security and radio frequency (RF) interferences mitigation for satellite systems, and demonstrate that they are not isolated. The action space for both cyber security and RF interferences are firstly summarized for satellite systems, based on which the mitigation schemes for both cyber security and RF interferences are given. A multi-layered satellite systems structure is provided with cross-layer design considering multi-path routing and channel coding, to provide great security and diversity gains for secure and robust satellite systems.

Energy Revolution Against Climate Change

International Nuclear Information System (INIS)

Potocnik, V.

2007-01-01

Energy revolution is taking place in the world with objective to mitigate consequences of evident climate change, caused mostly by emissions of the greenhouse gases from combustion of fossil fuels (coal, oil and natural gas). The principal elements of the energy revolution are decrease in energy consumption by increase in energy efficiency and substitution of fossil fuels by renewable energies, supported by 'clean' fossil fuels and nuclear energy. (author)

The Fourth Revolution: Educating Engineers for Leadership.

Science.gov (United States)

Mark, Hans; Carver, Larry

1988-01-01

Urges a change in engineering education for developing leaders. Describes three previous revolutions in American higher education which responded to the needs of the community. Suggests lifelong education as the fourth revolution. (YP)

Design of an Image Motion Compenstaion (IMC Algorithm for Image Registration of the Communication, Ocean, Meteorolotical Satellite (COMS-1

Directory of Open Access Journals (Sweden)

Taek Seo Jung

2006-03-01

Full Text Available This paper presents an Image Motion Compensation (IMC algorithm for the Korea's Communication, Ocean, and Meteorological Satellite (COMS-1. An IMC algorithm is a priority component of image registration in Image Navigation and Registration (INR system to locate and register radiometric image data. Due to various perturbations, a satellite has orbit and attitude errors with respect to a reference motion. These errors cause depointing of the imager aiming direction, and in consequence cause image distortions. To correct the depointing of the imager aiming direction, a compensation algorithm is designed by adapting different equations from those used for the GOES satellites. The capability of the algorithm is compared with that of existing algorithm applied to the GOES's INR system. The algorithm developed in this paper improves pointing accuracy by 40%, and efficiently compensates the depointings of the imager aiming direction.

Public and Private Responsibility for Mental Health: Mental Health's Fourth Revolution.

Science.gov (United States)

Dokecki, Paul R.

Three revolutions in the history of mental health were identified by Nicholas Hobbs: the humane revolution, the scientific and therapeutic revolution, and the public health revolution. The shift of responsibilities for mental health and substance abuse services from the public to the private sector may constitute a fourth mental health revolution.…

GIER: A Danish computer from 1961 with a role in the modern revolution of astronomy - II

Science.gov (United States)

Høg, Erik

2018-04-01

A Danish computer, GIER, from 1961 played a vital role in the development of a new method for astrometric measurement. This method, photon counting astrometry, ultimately led to two satellites with a significant role in the modern revolution of astronomy. A GIER was installed at the Hamburg Observatory in 1964 where it was used to implement the entirely new method for the measurement of stellar positions by means of a meridian circle, at that time the fundamental instrument of astrometry. An expedition to Perth in Western Australia with the instrument and the computer was a success. This method was also implemented in space in the first ever astrometric satellite Hipparcos launched by ESA in 1989. The Hipparcos results published in 1997 revolutionized astrometry with an impact in all branches of astronomy from the solar system and stellar structure to cosmic distances and the dynamics of the Milky Way. In turn, the results paved the way for a successor, the one million times more powerful Gaia astrometry satellite launched by ESA in 2013. Preparations for a Gaia successor in twenty years are making progress.

Interim Service ISDN Satellite (ISIS) hardware experiment development for advanced ISDN satellite designs and experiments

Science.gov (United States)

Pepin, Gerard R.

1992-01-01

The Interim Service Integrated Service Digital Network (ISDN) Satellite (ISIS) Hardware Experiment Development for Advanced Satellite Designs describes the development of the ISDN Satellite Terminal Adapter (ISTA) capable of translating ISDN protocol traffic into Time Division Multiple Access (TDMA) signals for use by a communications satellite. The ISTA connects the Type 1 Network Termination (NT1) via the U-interface on the line termination side of the CPE to the RS-499 interface for satellite uplink. The same ISTA converts in the opposite direction the RS-499 to U-interface data with a simple switch setting.

Interim Service ISDN Satellite (ISIS) hardware experiment design for advanced ISDN satellite design and experiments

Science.gov (United States)

Pepin, Gerard R.

1992-01-01

The Interim Service Integrated Services Digital Network (ISDN) Satellite (ISIS) Hardware Experiment Design for Advanced Satellite Designs describes the design of the ISDN Satellite Terminal Adapter (ISTA) capable of translating ISDN protocol traffic into time division multiple access (TDMA) signals for use by a communications satellite. The ISTA connects the Type 1 Network Termination (NT1) via the U-interface on the line termination side of the CPE to the V.35 interface for satellite uplink. The same ISTA converts in the opposite direction the V.35 to U-interface data with a simple switch setting.

Research of real-time communication software

Science.gov (United States)

Li, Maotang; Guo, Jingbo; Liu, Yuzhong; Li, Jiahong

2003-11-01

Real-time communication has been playing an increasingly important role in our work, life and ocean monitor. With the rapid progress of computer and communication technique as well as the miniaturization of communication system, it is needed to develop the adaptable and reliable real-time communication software in the ocean monitor system. This paper involves the real-time communication software research based on the point-to-point satellite intercommunication system. The object-oriented design method is adopted, which can transmit and receive video data and audio data as well as engineering data by satellite channel. In the real-time communication software, some software modules are developed, which can realize the point-to-point satellite intercommunication in the ocean monitor system. There are three advantages for the real-time communication software. One is that the real-time communication software increases the reliability of the point-to-point satellite intercommunication system working. Second is that some optional parameters are intercalated, which greatly increases the flexibility of the system working. Third is that some hardware is substituted by the real-time communication software, which not only decrease the expense of the system and promotes the miniaturization of communication system, but also aggrandizes the agility of the system.

Visible light communication: Applications, architecture, standardization and research challenges

OpenAIRE

Khan, Latif Ullah

2016-01-01

The Radio Frequency (RF) communication suffers from interference and high latency issues. Along with this, RF communication requires a separate setup for transmission and reception of RF waves. Overcoming the above limitations, Visible Light Communication (VLC) is a preferred communication technique because of its high bandwidth and immunity to interference from electromagnetic sources. The revolution in the field of solid state lighting leads to the replacement of florescent lamps by Light E...

The Orbital Dynamics of Synchronous Satellites: Irregular Motions in the 2 : 1 Resonance

Directory of Open Access Journals (Sweden)

Jarbas Cordeiro Sampaio

2012-01-01

Full Text Available The orbital dynamics of synchronous satellites is studied. The 2 : 1 resonance is considered; in other words, the satellite completes two revolutions while the Earth completes one. In the development of the geopotential, the zonal harmonics J20 and J40 and the tesseral harmonics J22 and J42 are considered. The order of the dynamical system is reduced through successive Mathieu transformations, and the final system is solved by numerical integration. The Lyapunov exponents are used as tool to analyze the chaotic orbits.

Newspaper Uses of Satellite Technology.

Science.gov (United States)

Johns, David

Replacing slower mail service, satellite transmission now gives the newspaper industry a practical and almost spontaneous method for sending all kinds of information to any newspaper across the country. Unlike other communication industries, newspapers did not begin to make widespread use of satellite technology until 1979, when government…

47 CFR 25.276 - Points of communication.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Points of communication. 25.276 Section 25.276 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS... International Telecommunications Satellite Organization and Inmarsat, are subject to the policies set forth in...

Education in Revolution: Is Iran Duplicating the Chinese Cultural Revolution?

Science.gov (United States)

Sobhe, Khosrow

1982-01-01

Compares Chinese and Iranian Cultural Revolutions via examination of similarities and differences between the two and draws lessons from the Chinese experience for Iran or any other developing nations which decides to politicize its education systems. (Author/AH)

Russia’s Reactions to the Color Revolutions

Science.gov (United States)

2017-03-01

leadership brought into power by the Tulip Revolution also sought closer ties with Russia, and moved away from the democratic ideal espoused by their...words) The color revolutions, the popular democratic protests that occurred in Georgia, Ukraine, and Kyrgyzstan from 2003–2005 and overturned the pro...PAGE INTENTIONALLY LEFT BLANK v ABSTRACT The color revolutions, the popular democratic protests that occurred in Georgia, Ukraine, and

Application of the advanced communications technology satellite for teleradiology and telemedicine

Science.gov (United States)

Stewart, Brent K.; Carter, Stephen J.; Rowberg, Alan H.

1995-05-01

The authors have an in-kind grant from NASA to investigate the application of the Advanced Communications Technology Satellite (ACTS) to teleradiology and telemedicine using the JPL developed ACTS Mobile Terminal (AMT) uplink. This experiment involves the transmission of medical imagery (CT, MR, CR, US and digitized radiographs including mammograms), between the ACTS/AMT and the University of Washington. This is accomplished by locating the AMT experiment van in various locations throughout Washington state, Idaho, Montana, Oregon and Hawaii. The medical images are transmitted from the ACTS to the downlink at the NASA Lewis Research Center (LeRC) in Cleveland, Ohio, consisting of AMT equipment and the high burst rate-link evaluation terminal (HBR-LET). These images are then routed from LeRC to the University of Washington School of Medicine (UWSoM) through the Internet and public switched Integrated Serviced Digital Network (ISDN). Once images arrive in the UW Radiology Department, they are reviewed using both video monitor softcopy and laser-printed hardcopy. Compressed video teleconferencing and transmission of real-time ultrasound video between the AMT van and the UWSoM are also tested. Image quality comparisons are made using both subjective diagnostic criteria and quantitative engineering analysis. Evaluation is performed during various weather conditions (including rain to assess rain fade compensation algorithms). Compression techniques also are tested to evaluate their effects on image quality, allowing further evaluation of portable teleradiology/telemedicine at lower data rates and providing useful information for additional applications (e.g., smaller remote units, shipboard, emergency disaster, etc.). The medical images received at the UWSoM over the ACTS are directly evaluated against the original digital images. The project demonstrates that a portable satellite-land connection can provide subspecialty consultation and education for rural and remote

Perception of emotional climate in a revolution: Test of a multistage theory of revolution in the Tunisian context.

Science.gov (United States)

Rimé, Bernard; Yzerbyt, Vincent; Mahjoub, Abdelwahab

2017-12-01

Participation in social movements and collective action depends upon people's capacity to perceive their societal context. We examined this question in the context of Arab Spring revolutions. In a classic theory of revolution highlighting the role of collective emotions, Brinton (1938) claimed that revolutions, far from chaos, proceed in an orderly sequence involving four stages: euphoria, degradation, terror, and restoration. The emotional climate (EC) as perceived by ordinary Tunisian citizens (2,699 women and 3,816 men) was measured during the 4 years of the Tunisian revolution. A quadratic pattern of perceived EC measures over time provided strong support to Brinton's model. In addition, three different analyses suggested the presence of four distinct stages in the evolution of perceived EC. Third, the socio-political developments in Tunisia during the four stages proved entirely consistent with both Brinton's theoretical model and the perceived EC indicators. Finally, social identification proved closely related to the temporal evolution of positive EC scores. In sum, data from this study not only lend support to the views put forth in an heretofore untested classic theory of revolution but also demonstrate that psychosocial measurements can validly monitor a major process of socio-political transformation. © 2017 The British Psychological Society.

Electromagnetic Modeling of the Propagation Characteristics of Satellite Communications Through Composite Precipitation Layers, Part1: Mathematical Formulation

Directory of Open Access Journals (Sweden)

H.M. Al-Rizzo

2000-12-01

Full Text Available A systematic and general formulation of a Propagation Simulation Program (PSP is developed for the coherent field of microwave and millimeter wave carrier signals traversing intermediate layered precipitation media, taking into account the random behavior of particle size, orientation, shape and concentration distributions.  Based on a rigorous solution of the volumetric multiple-scattering integral equations, the formalism offers the capability of treating the potential transmission impairments on satellite-earth links and radar remote sensing generated by composite atmospheric layers of precipitation in conjunction with the finite polarization isolation of dual-polarized transmitting and receiving antennas. A multi-layered formulation is employed which encompasses an ensemble of discrete particles comprising an arbitrary mixture of ice crystals, melting snow and raindrops that may exist simultaneously along satellite-earth communication paths.

The Computer and the Fourth Revolution.

Science.gov (United States)

Molnar, Andrew R.

An overview is provided of the Fourth Revolution, i.e., the revolution which is taking place in education as a result of the introduction of computers into the field. The growth of computing in education, especially in higher education, is traced, and some major National Science Foundation (NSF) programs are mentioned. Following this, a few of the…

An information revolution in orthopaedics.

Science.gov (United States)

Goldberg, A J; MacGregor, A; Spencer, S A

2012-04-01

With the established success of the National Joint Registry and the emergence of a range of new national initiatives for the capture of electronic data in the National Health Service, orthopaedic surgery in the United Kingdom has found itself thrust to the forefront of an information revolution. In this review we consider the benefits and threats that this revolution poses, and how orthopaedic surgeons should marshal their resources to ensure that this is a force for good.

Technique for Geolocation of EMI Emitters by O3B Satellites

Science.gov (United States)

2016-06-01

Communication Systems: An Introduction to Signals and Noise in Electrical Communications , 5th edition (New York: McGraw -Hill, 2011), 4. 6 system to...the only one caused by humans , that will be our focus—the others can be thought of as the cost of doing business in satellite communications and can...SATELLITE COMMUNICATIONS OVERVIEW ...............................2  B.  EMI AND JAMMING OVERVIEW .......................................................5

Solar effects on communications

International Nuclear Information System (INIS)

Cleveland, F.; Malcolm, W.; Nordell, D.E.; Zirker, J.

1991-01-01

When people involved in the power industry think of Solar Magnetic Disturbances (SMD), they normally consider the potential for disrupting power transmission which results form solar-induced disturbances to the earth's magnetic field known as geomagnetic storms. However, in addition to the disruption of power transmission, solar phenomena can interfere with utility communication systems. Utilities use many different types of communication media, some of which can be affected by various solar phenomena. These include wire-based facilities (metallic cables and power line carrier), radio systems (HF, VHF, UHF mobile radio, microwave networks, and satellite transmissions), and fiber optic systems. This paper reports that the solar flares and other solar phenomena can affect these media through different mechanisms: Radio communications can be disturbed by flare-induced changes in the ionispheric layer of the atmosphere; Cable communications can be disrupted by the flare-induced changes in the magnetosphere which surrounds the earth. These changes, in turn, induce currents in the power equipment that energizes long communications cables; Satellite communications can be disrupted by the flare-induced perturbations of satellite orbits and equipment

The performance evaluation of a new neural network based traffic management scheme for a satellite communication network

Science.gov (United States)

Ansari, Nirwan; Liu, Dequan

1991-01-01

A neural-network-based traffic management scheme for a satellite communication network is described. The scheme consists of two levels of management. The front end of the scheme is a derivation of Kohonen's self-organization model to configure maps for the satellite communication network dynamically. The model consists of three stages. The first stage is the pattern recognition task, in which an exemplar map that best meets the current network requirements is selected. The second stage is the analysis of the discrepancy between the chosen exemplar map and the state of the network, and the adaptive modification of the chosen exemplar map to conform closely to the network requirement (input data pattern) by means of Kohonen's self-organization. On the basis of certain performance criteria, whether a new map is generated to replace the original chosen map is decided in the third stage. A state-dependent routing algorithm, which arranges the incoming call to some proper path, is used to make the network more efficient and to lower the call block rate. Simulation results demonstrate that the scheme, which combines self-organization and the state-dependent routing mechanism, provides better performance in terms of call block rate than schemes that only have either the self-organization mechanism or the routing mechanism.

Proceedings of the Twenty-First NASA Propagation Experiments Meeting (NAPEX XXI) and the Advanced Communications Technology Satellite (ACTS) Propagation Studies Miniworkshop

Science.gov (United States)

Golshan, Nasser (Editor)

1997-01-01

The NASA Propagation Experimenters (NAPEX) meeting is convened each year to discuss studies supported by the NASA Propagation Program. Representatives from the satellite communications industry, academia and government who have an interest in space-ground radio wave propagation are invited to NAPEX meetings for discussions and exchange of information. The reports delivered at this meeting by program managers and investigators present recent activities and future plans. This forum provides an opportunity for peer discussion of work in progress, timely dissemination of propagation results, and close interaction with the satellite communications industry. NAPEX XXI took place in El Segundo, California on June 11-12, 1997 and consisted of three sessions. Session 1, entitled "ACTS Propagation Study Results & Outcome " covered the results of 20 station-years of Ka-band radio-wave propagation experiments. Session 11, 'Ka-band Propagation Studies and Models,' provided the latest developments in modeling, and analysis of experimental results about radio wave propagation phenomena for design of Ka-band satellite communications systems. Session 111, 'Propagation Research Topics,' covered a diverse range of propagation topics of interest to the space community, including overviews of handbooks and databases on radio wave propagation. The ACTS Propagation Studies miniworkshop was held on June 13, 1997 and consisted of a technical session in the morning and a plenary session in the afternoon. The morning session covered updates on the status of the ACTS Project & Propagation Program, engineering support for ACTS Propagation Terminals, and the Data Center. The plenary session made specific recommendations for the future direction of the program.

The large satellite program of ESA and its relevance for broadcast missions

Science.gov (United States)

Fromm, H.-H.; Herdan, B. L.

1981-03-01

In an investigation of the market prospects and payload requirements of future communications satellites, it was concluded that during the next 15 years many space missions will demand larger satellite platforms than those currently available. These platforms will be needed in connection with direct-broadcasting satellites, satellites required to enhance capacities in the case of traditional services, and satellites employed to introduce new types of satellite-based communications operating with small terminals. Most of the larger satellites would require the Ariane III capability, corresponding to about 1400 kg satellite mass in geostationary orbit. Attention is given to L-SAT platform capabilities and broadcast payload requirements, taking into account a European direct-broadcast satellite and Canadian direct-broadcast missions.

Ruin and Revolution in ``Hamlet."

Science.gov (United States)

Usher, P. D.

1999-05-01

In the cosmic allegorical interpretation of Shakespeare's "Hamlet" (BAAS 28, 859 & 1305, 1996; Mercury 26:1, 20, 1997; RPS 18:3, 6, 1997; Giornale di Astronomia 24:3, 27, 1998), the usurper King Claudius, namesake of Ptolemy, personifies geocentricity. Textual support for this reading is found in 1.2 where Hamlet is associated with the Sun, as befits a rightful heir, while Claudius is associated with the Earth. In 3.3 Claudius fears Hamlet's antics. Rosencrantz states that the lives of many depend on the well-being of the King. He warns that if the King were to be imperiled, his subjects, those "ten thousand lesser things", would fall in a "boisterous ruin" along with "each small annexment" and "petty consequence." These 10,000 lesser lights are the naked eye stars (mv ~ 6.5) which would collapse with the demise of the pre-Diggesian firmament, along with ancient planets and their geometrical contrivances. In 5.1 Shakespeare puns on "De revolutionibus" when he refers to "fine revolution." The double meaning of "revolution" (alteration, orbital motion) was in use long before 1600. Since "revolution" is used in the context of digging, it may refer as much to the Diggesian as the Copernican Revolution. Shakespeare's prescience is revealed by his anticipation of change, as encapsulated geocentricity is transformed to stellar boundlessness, while his presence is suggested by fatherly concerns and ghost-like direction.

"CLASS APPROACH" AND "PROLETARIAN CHARACTER" OF RUSSIAN REVOLUTION OF 1917

Directory of Open Access Journals (Sweden)

Эдуард Эдуардович Шульц

2014-12-01

Full Text Available Study of the problem of “class character” of 1917’ revolution and competency of the term “proletarian revolution”. The author considers questions of participation of various social groups in the Russian revolution, draws analogies of social composition of previous revolutions, considers the principle of “proletarian revolution”, as an ideology element for positioning of Bolsheviks and power capture. It is necessary to consider that an age, gender and national factor played much bigger role un Russian revolution than class factor. Revolution in Russia in many respects leaned on young generations which made more than a third of the population of the Russian Empire by 1917. In fight against tsarism separate calculation was based on the non-russian population and national suburbs of the empire. The special role in the Russian revolution was played by the peasantry. Revolution happened in the capital (in two capitals in Russia, the peasantry remained indifferent to revolution while Bolsheviks didn't begin to take away from them the food violently. This period:(summer - fall of 1919 became the time of peak of the Civil war. However return of landowners and their claim for property of the land forced peasants to turn bayonets for revolution and the earth and, eventually, to provide to Bolsheviks a victory in the Civil war.

Lightning-generated whistler waves observed by probes on the Communication/Navigation Outage Forecast System satellite at low latitudes

Science.gov (United States)

Holzworth, R. H.; McCarthy, M. P.; Pfaff, R. F.; Jacobson, A. R.; Willcockson, W. L.; Rowland, D. E.

2011-06-01

Direct evidence is presented for a causal relationship between lightning and strong electric field transients inside equatorial ionospheric density depletions. In fact, these whistler mode plasma waves may be the dominant electric field signal within such depletions. Optical lightning data from the Communication/Navigation Outage Forecast System (C/NOFS) satellite and global lightning location information from the World Wide Lightning Location Network are presented as independent verification that these electric field transients are caused by lightning. The electric field instrument on C/NOFS routinely measures lightning-related electric field wave packets or sferics, associated with simultaneous measurements of optical flashes at all altitudes encountered by the satellite (401-867 km). Lightning-generated whistler waves have abundant access to the topside ionosphere, even close to the magnetic equator.

The Fourth Revolution

Science.gov (United States)

Abelson, Philip H.

1972-01-01

Comments on the conclusions of the Carnegie Commission on Higher Education's report, The Fourth Revolution: Instructional Technology in Higher Education,'' and advocates effort in exploiting the new technology and in assessing the possible adverse effects. (AL)

Geostationary Communications Satellites as Sensors for the Space Weather Environment: Telemetry Event Identification Algorithms

Science.gov (United States)

Carlton, A.; Cahoy, K.

2015-12-01

Reliability of geostationary communication satellites (GEO ComSats) is critical to many industries worldwide. The space radiation environment poses a significant threat and manufacturers and operators expend considerable effort to maintain reliability for users. Knowledge of the space radiation environment at the orbital location of a satellite is of critical importance for diagnosing and resolving issues resulting from space weather, for optimizing cost and reliability, and for space situational awareness. For decades, operators and manufacturers have collected large amounts of telemetry from geostationary (GEO) communications satellites to monitor system health and performance, yet this data is rarely mined for scientific purposes. The goal of this work is to acquire and analyze archived data from commercial operators using new algorithms that can detect when a space weather (or non-space weather) event of interest has occurred or is in progress. We have developed algorithms, collectively called SEER (System Event Evaluation Routine), to statistically analyze power amplifier current and temperature telemetry by identifying deviations from nominal operations or other events and trends of interest. This paper focuses on our work in progress, which currently includes methods for detection of jumps ("spikes", outliers) and step changes (changes in the local mean) in the telemetry. We then examine available space weather data from the NOAA GOES and the NOAA-computed Kp index and sunspot numbers to see what role, if any, it might have played. By combining the results of the algorithm for many components, the spacecraft can be used as a "sensor" for the space radiation environment. Similar events occurring at one time across many component telemetry streams may be indicative of a space radiation event or system-wide health and safety concern. Using SEER on representative datasets of telemetry from Inmarsat and Intelsat, we find events that occur across all or many of

Revolution in Detection Affairs

Energy Technology Data Exchange (ETDEWEB)

Stern W.

2013-11-02

The detection of nuclear or radioactive materials for homeland or national security purposes is inherently difficult. This is one reason detection efforts must be seen as just one part of an overall nuclear defense strategy which includes, inter alia, material security, detection, interdiction, consequence management and recovery. Nevertheless, one could argue that there has been a revolution in detection affairs in the past several decades as the innovative application of new technology has changed the character and conduct of detection operations. This revolution will likely be most effectively reinforced in the coming decades with the networking of detectors and innovative application of anomaly detection algorithms.

Digital Revolution and Innovative Business Models in Healthcare: Global Trends and Russian Realities.

Science.gov (United States)

Bereznoy, A V; Saygitov, R T

Digital revolution is one of the major global trends resulting in the unprecedented scale and depth of penetration of information and communication technologies into all sectors of national economy, including healthcare. The development of this trend brought about high expectations related to the improvement of quality of medical assistance, accessibility and economic efficiency of healthcare services. However, euphoria of the first steps of digital revolution is passing now, opening doors to more realistic analysis of opportunities and conditions of realization of the true potential hidden in the digital transformation of healthcare. More balanced perception of the peculiarities of innovation processes in the sector is coming together with understanding of the serious barriers, hampering implementation of the new ideas and practices due to complicated interweaving of social, economic, ethical and psychological factors. When taking into account the industry specifics it becomes evident that digital revolution cannot be a quick turnaround but rather would pass a number of phases and is likely to last more than one decade. In this context the article focuses on the prospects of the new business models, capable of making significant changes in today’s economic landscape of the sector (including uber-medicine, retail clinics, retainer medicine, network models of medical services). The authors also provide assessment of the current situation and perspectives of digital healthcare development in Russia.

Scientific revolution, incommensurability and truth in theories ...

African Journals Online (AJOL)

Scientific revolution, incommensurability and truth in theories: objection to Kuhn's perspective. ... AFRREV STECH: An International Journal of Science and Technology ... The core of our discussion is, ultimately, to provide a clearer and broader picture of the general characteristics of scientific revolution or theory change.

A Framework for Developing Artificial Intelligence for Autonomous Satellite Operations

Science.gov (United States)

Anderson, Jason L.; Kurfess, Franz J.; Puig-Suari, Jordi

2009-09-01

In the world of educational satellites, student teams manually conduct operations daily. Educational satellites typically travel in a Low Earth Orbit allowing communication for approximately thirty minutes each day. Manual operations during these times is manageable for student teams as the required manpower is minimal. The international Global Educational Network for Satellite Operations (GENSO), however, promises satellite contact upwards of sixteen hours per day by connecting earth stations globally through the Internet. This large increase in satellite communication time makes manual student operations unreasonable and alternatives must be explored. This paper introduces a framework to conduct autonomous satellite operations using different AI methodologies. This paper additionally demonstrates the framework's usability by introducing a sample rule-based implementation for Cal Poly's CubeSat, CP3.

MARAD maritime experiments using the NASA ATS-6 satellite

Science.gov (United States)

Brandel, D. L.; Kaminsky, Y.

1975-01-01

The objectives of the MARAD maritime experiments (conducted in the L-band fan beam mode) using the ATS-6 satellite are detailed. They include the following: (1) to evaluate the economic benefits of fleet operators through the use of satellite communications, (2) to evaluate performance criteria for shipboard terminal equipment needed to establish various grades of fleet operations services using commercial satellite systems, (3) to determine the effects of signal propagation, ship radio frequency noise, and ship antenna pointing on the maritime communications and navigation channel, and (4) to evaluate various modems for the transmission and reception of voice, data and position location signals via satellite systems.

Assessment of Intergenerational Communication and Relationships

Science.gov (United States)

Strom, Robert D.; Strom, Paris S.

2015-01-01

The revolution in communication technology has resulted in more age-segregated conversation among adolescents. In a similar way, older adults have increased online conversations with their peers. This article explores some obstacles that prevent the intergenerational connections needed for mutual understanding and care. Several research emphases…

Satellite Antenna Pointing Procedure Driven by the Ground Service Quality

Science.gov (United States)

Yasui, Yoshitsugu

A satellite antenna alignment technique is proposed to ensure terrestrial service quality for users. The antenna bore sight orientation is calculated directly from measured data acquired from general ground receivers, which intercept the communication radio waves from any position on the earth's surface. The method coordinates the satellite pointing parameters with signal strength at the receivers while considering location-specific geographical and antenna radiation characteristics and control accuracy. The theoretical development and its validity are examined in the course of equation derivation. Actual measured data of an existing satellite at the maneuver was applied to the method, and the capability was demonstrated and verified. With the wide diversity of satellite usage, such as for mobile communications, temporary network deployment or post-launch positioning accommodations, the proposed method provides a direct evaluation of satellite communication performance at the service level, in conjunction with using high frequency spot beam antennas, which are highly susceptible to pointing gain. This can facilitate swift and flexible satellite service planning and deployment for operators.

Finite element model for nonlinear shells of revolution

International Nuclear Information System (INIS)

Cook, W.A.

1979-01-01

Nuclear material shipping containers have shells of revolution as basic structural components. Analytically modeling the response of these containers to severe accident impact conditions requires a nonlinear shell-of-revolution model that accounts for both geometric and material nonlinearities. Existing models are limited to large displacements, small rotations, and nonlinear materials. The paper presents a finite element model for a nonlinear shell of revolution that will account for large displacements, large strains, large rotations, and nonlinear materials

The digital revolution in energy

International Nuclear Information System (INIS)

Therme, Jean

2015-01-01

The growth of renewable sources of energy on the planet (in particular, solar power) is deeply altering the economics of energy. The decentralization of decision-making, the placing of users at the center of systems, the management of energy consumption in buildings, new forms of mobility... all these are expectations that digital technology can satisfy. Do digital technology and energy naturally converge... or will there be a revolution? For sure, a revolution, but one that has to take place, first of all, in our heads

47 CFR 25.401 - Satellite DARS applications subject to competitive bidding.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Satellite DARS applications subject to competitive bidding. 25.401 Section 25.401 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Competitive Bidding Procedures for DARS § 25.401...

47 CFR 25.140 - Qualifications of fixed-satellite space station licensees.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Qualifications of fixed-satellite space station licensees. 25.140 Section 25.140 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses Space Stations § 25.140 Qualifications...

Cross-polarisation discrimination-induced interference in dual-polarised high-capacity satellite communication systems

Directory of Open Access Journals (Sweden)

Abdulkareem Sarki Karasuwa

2016-05-01

Full Text Available The design of spectrally-efficient, high-throughput satellite (HTS systems with capacity approaching one terabit per second requires operating at Ka-band frequencies and above, where there are several gigahertz of allocated radio spectrum, using multiple spot beams with dual orthogonal polarisation mode. At these high frequencies, rain attenuation poses a major obstacle to the design of high-availability satellite links which are needed for the realisation of ubiquitous broadband multimedia communication services including high-speed Internet access at rural and remote locations. Furthermore, depolarisation-induced interference in such systems could have a performance-limiting impact if a co-channel cross-polar signal combines with system noise to drive the carrier-to-noise-plus-interference ratio (CNIR below an acceptable threshold. This paper employs real measurement data to investigate the impact of depolarisation-induced interference on dual-polarised HTS systems for temperate and tropical climatic regions. Scenarios that cause significant system performance degradation are analysed, including the effects of signal frequency, antenna size, and regional rainfall rate. The impact of depolarisation on system performance is quantified by the reductions in the CNIR and link availability of a dual-polarised system when compared with those of a similarly-dimensioned single-polarised system.

NEW EDUCATION FOR NEW INFORMATION AND TECHNOLOGICAL REVOLUTIONS

Directory of Open Access Journals (Sweden)

Вадим Валерьевич Гриншкун

2017-12-01

Full Text Available The development of the education system are largely determined by scientific and technical progress. In recent times it is spoken about approach of a new, fourth industrial revolution. According to researchers, this revolution coincides with a series of information revolutions and is based on the development and implementation of new means and technologies of informatization, such as the Internet of things, VR and AR, 3D-printing, and quantum computers. It is obvious that the education system needs to respond to these challenges. For the solution of relevant problems the article describes a number of urgent measures to be taken in education in the coming years. These measures are systematized depending on the factors of the fourth industrial revolution. In particular, special training of teachers, establishment of a closer partnership organizations vocational education with industry, fundamentalization of training of students, is invariant to rapidly changing technologies, and other measures. Special attention is paid to development of information technologies and approaches to the allocation information revolutions. Their change also has an impact on approaches to reforming the education system.

Satellite switching concepts for European business services in the nineties

Science.gov (United States)

Lombard, D.; Rouffet, D.

A first generation of business communication satellites are now operational or to be launched. Increased demands for communication satellite facilities will develop, if special services, such as videoconferencing, can be provided at a reasonable cost. For such developments, it will be necessary to define a second generation of business communication satellites. The present investigation evaluates briefly the size of the expected European market for 1995. A study is conducted of the payload structure for the required satellite system, and aspects related to link budgets and power consumption are explored. It is found that system dimensioning is determined by the up-link and by technology. Critical factors are related to the output and input multiplexors for the link budget, the switching matrix, and implications for the mass budget. The best trade-off between technological, mass, and link budget limitations is achieved in connection with the employment of a hinged antennas satellite, using an intermediate number of spot beams and associated earth stations of reasonable size.

Revolution in Communication Technologies: Impact on Distance Education

Science.gov (United States)

Rajesh, M.

2015-01-01

Information and Communication Technologies have transformed the way the world lives and thinks. Education, especially, Distance Education is no different. While the technologies per se are an important factor, the social milieus in which these technologies are implemented are equally important. Technological convergence in the Indian context…

Satellite Demonstration: The Videodisc Technology.

Science.gov (United States)

Propp, George; And Others

1979-01-01

Originally part of a symposium on educational media for the deaf, the paper describes a satellite demonstration of video disc materials. It is explained that a panel of deaf individuals in Washington, D.C. and another in Nebraska came into direct two-way communication for the first time, and video disc materials were broadcast via the satellite.…

Live Satellite Communications... An Exciting Teaching Aid

Science.gov (United States)

Journal of Aerospace Education, 1976

1976-01-01

Describes ways that orbiting satellites carrying amateur radios can be used in the classroom at various grade levels to supplement physics, mathematics, electronics, and social science curricula. (MLH)

The ebook revolution

CERN Document Server

Sheehan, Kate

2013-01-01

The eBook Revolution: A Primer for Librarians on the Front Lines is exactly what its title promises: an essential resource for librarians facing the formidable task of coordinating the library-wide transition to eBooks and fielding questions from patrons

Green revolution: impacts, limits, and the path ahead.

Science.gov (United States)

Pingali, Prabhu L

2012-07-31

A detailed retrospective of the Green Revolution, its achievement and limits in terms of agricultural productivity improvement, and its broader impact at social, environmental, and economic levels is provided. Lessons learned and the strategic insights are reviewed as the world is preparing a "redux" version of the Green Revolution with more integrative environmental and social impact combined with agricultural and economic development. Core policy directions for Green Revolution 2.0 that enhance the spread and sustainable adoption of productivity enhancing technologies are specified.

Urbanism Faced with the New Urban Revolution

DEFF Research Database (Denmark)

Ascher, François

2002-01-01

Med den industrielle revolution fulgte den urbane revolution og urbanismen som bymæssig videns- og planlægningsdisciplin. Med de nye informations- og kommunikationsteknologier står vi i dag over for samfundsmæssige forandringer, som sætter en ny urban revolution på dagsordenen. Urbanismen er...... tilsvarende ved at blive afløst af en "meta-urbanisme", som adskiller sig fra den foregående med hensyn til målsætninger, kundskabsmæssige redskaber og handlingsinstrumenter. I artiklen redegøres for sammenhænge mellem disse teknologiske, samfundsmæssige, bymæssige og urbanistiske forandringer....

Taxation and the American Revolution

Directory of Open Access Journals (Sweden)

John Passant

2017-09-01

Full Text Available This article looks at the interrelationship between revolution and tax in the context of the American Revolution. It examines the role of ordinary people in demanding, among other things, as part of wider demands for democracy and equality, no taxation without representation. The article aims to reintroduce the neglected notions of class and class struggle into current discussions and debates about tax and history, putting the people back into academic narratives about the history of taxation and to their place as political actors on history’s stage.

Solar Power Satellites

CERN Document Server

Flournoy, Don M

2012-01-01

Communication satellites are a $144 billion industry. Is there any space-based industry that could possibly beat that market? 'Solar Power Satellites' shows why and how the space satellite industry will soon begin expanding its market from relaying signals to Earth to generating energy in space and delivering it to the ground as electricity. In all industrialized nations, energy demand is growing exponentially. In the developing world, the need for energy is as basic as food and water. The Sun's energy is available everywhere, and it is non-polluting. As business plans demonstrate its technical feasibility, commercial potential, and environmental acceptability, every country on Earth will look to space for the power it needs.

The 1917 Revolution in Tuva

Directory of Open Access Journals (Sweden)

Vladimir G. Dazishen

2017-12-01

Full Text Available Based on both archival and previously published documents, this article examines the issue of impact that Russia’s revolution of 1917 had on contemporary events in Tuva. Tuva acceded to the USSR in 1944, many years after the Bolshevik revolution and the rise of the Soviet state. However, we postulate that the “Soviet history” of Tuva, just like that of Russia, started in 1917. Soviet historiography prioritized the Great October Socialist revolution, but the events of 1917 began in February. The course of February revolution in Tannu Tuva Uriankhai did not automatically lead to the victory of the Bolsheviks and the establishment of the Soviet power. In spring and summer 1917, revolutionary change in Tuva was largely peaceful and constructive. Supported by the whole Russian population of Tuva, members of the Socialist Revolutionary Party formed the new local government and coopted representatives of Tuvan principalities as partners of the new Russian power. Bolshevik ideas, howsoever high the popularity of their supporters in Tuva might have been, did not find massive endorsement in the region. Consequently, Uriankhai saw no “dual power” (dvoevlastiie in 1917, and the victory of communists in Russia did not mean that the power should transfer to them in Tuva as well. One of the most complex issues of the revolution in the region was incorporating the political system of Tuva into that of the Russian Republic. The complications of the “Uriankhai issue” and the rise of Tuvan separatism did not lead to interethnic conflicts, and the use of force to settle the burning issues was not deemed mandatory. On the whole, both the revolutionary events of 1917 and the vocal presence of all Russian political forces in the region pointed towards the future accession of Tuva into the Russian Republic. Our study made use of sources from the Foreign Policy Archive of the Russian Empire in Moscow, as well as regional archives of Tuva, Novosibirsk

Gaussian entanglement distribution via satellite

Science.gov (United States)

Hosseinidehaj, Nedasadat; Malaney, Robert

2015-02-01

In this work we analyze three quantum communication schemes for the generation of Gaussian entanglement between two ground stations. Communication occurs via a satellite over two independent atmospheric fading channels dominated by turbulence-induced beam wander. In our first scheme, the engineering complexity remains largely on the ground transceivers, with the satellite acting simply as a reflector. Although the channel state information of the two atmospheric channels remains unknown in this scheme, the Gaussian entanglement generation between the ground stations can still be determined. On the ground, distillation and Gaussification procedures can be applied, leading to a refined Gaussian entanglement generation rate between the ground stations. We compare the rates produced by this first scheme with two competing schemes in which quantum complexity is added to the satellite, thereby illustrating the tradeoff between space-based engineering complexity and the rate of ground-station entanglement generation.

The changing face of terrorism in the 21st century: the communications revolution and the virtual community of hatred.

Science.gov (United States)

Post, Jerrold M; McGinnis, Cody; Moody, Kristen

2014-01-01

There are no psychological characteristics or psychopathology separating terrorists from the general population. Rather, it is group dynamics, with a particular emphasis on collective identity, that helps to explain terrorist psychology. Just as there is a diverse spectrum of kinds of terrorism, so too is there a spectrum of terrorist psychologies. Some terrorists, those in nationalist-separatist groups, such as Fatah and the IRA, are continuing with the mission of their parents who are dissident to the regime. The opposite generational provenance is seen among social-revolutionary terrorists, such as the Weather Underground and the Red Army Faction in Germany, who are rebelling against their parents' generation, which is loyal to the regime. Four waves of terrorism can be distinguished: the "anarchist wave"; the "anti-colonial wave" (nationalist-separatist), with minority groups seeking to be liberated from their colonial masters or from the majority in their country; the "new left" wave (social-revolutionary); and now the "religious" wave. With the communications revolution, a new phenomenon is emerging which may presage a fifth wave: lone wolf terrorists who through the Internet are radicalized and feel they belong to the virtual community of hatred. A typology of lone wolf terrorism is proposed. Copyright © 2014 John Wiley & Sons, Ltd.

Next Generation Source Measuments: CRADA partner communication sheet

Science.gov (United States)

Partnerships to Advance Next Gen. Source MeasurementsA growing number of government, academic, and industry groups are recognizing the revolution in air pollution and greenhouse gas source measurement science enabled by the rapid advances in sensors, communications, data integrat...

The Fourth Revolution in Teaching: Meta-Analyses.

Science.gov (United States)

Kulik, James A.

Three major educational revolutions have been the advent of writing, the use of books as teaching tools, and the shift in educational responsibility from the home to the school. The fourth revolution, which is based on the use of electronic technology in teaching, began with programmed teaching machines, individualized instruction, and the…

Analysis of Development Plans from Communications Perspective

Directory of Open Access Journals (Sweden)

Zohreh Shahghasemi

2016-12-01

Full Text Available The movement towards the goals of "Vision plan 1404" needs the perception of the requirements to prepare plans for achieving the favorite objectives of development. With the advent of the information age, the rules of development policy-making strongly have changed in the world and also unique opportunities areprovided by variables of communications for countries that have been in early stages of development. Based on this, considering the communications in macro-level and in the political, social, economic and cultural development plans is important and necessary. This requires a review and pathology of previous plans and evaluation of their strengths and weaknesses for preparing of more comprehensive future plans. Themain question of this study is: what is the approach of development plans to communications section after Islamic revolution?  Which aspects of communications are considered, and what aspects are ignored?  This study analyzes five development plans after the revolution, by using of qualitative content analysis. Results show that in all five-year plans the focus was on hardware and quantitative dimensions of communication development and media, but qualitative and content aspects, such as the right to universal access to information, freedom to obtain and disseminate information within the constitution, freedom of speech and press, a move towards the information society and knowledge-based, also other dimensions of communications such as human, traditional and social communication has been less considered. In the fourth development plan that is "knowledge" – centered, new fields of communications has been studied comprehensively in comparison to other plans. According to these approaches and new scientific and experimental perspectives, this paper suggests further engagement in communications necessity for development policy-making.

Prediction Method for Rain Rate and Rain Propagation Attenuation for K-Band Satellite Communications Links in Tropical Areas

Directory of Open Access Journals (Sweden)

Baso Maruddani

2015-01-01

Full Text Available This paper deals with the prediction method using hidden Markov model (HMM for rain rate and rain propagation attenuation for K-band satellite communication link at tropical area. As is well known, the K-band frequency is susceptible of being affected by atmospheric condition, especially in rainy condition. The wavelength of K-band frequency which approaches to the size of rain droplet causes the signal strength is easily attenuated and absorbed by the rain droplet. In order to keep the quality of system performance for K-band satellite communication link, therefore a special attention has to be paid for rain rate and rain propagation attenuation. Thus, a prediction method for rain rate and rain propagation attenuation based on HMM is developed to process the measurement data. The measured and predicted data are then compared with the ITU-R recommendation. From the result, it is shown that the measured and predicted data show similarity with the model of ITU-R P.837-5 recommendation for rain rate and the model of ITU-R P.618-10 recommendation for rain propagation attenuation. Meanwhile, statistical data for measured and predicted data such as fade duration and interfade duration have insignificant discrepancy with the model of ITU-R P.1623-1 recommendation.

Europe at the crossroads: The future of its satellite communications industry

Science.gov (United States)

Bartholome, Pierre; Battrick, B.

1993-11-01

Ways of adapting the European Space Agency's role to the new industrial environment of satellite communications, which is characterized by the disappearance of traditional monopolies and the introduction of competition, are presented. As far as ESA is concerned, it is found that a general consensus exists to recommend that the agency should take a much wider view of its role as a research and development (R&D) organization. It should no longer restrict its field of activity to space technology only, but should take a more global approach. More emphasis should be placed on the development of complete communications systems and of commercial applications. European industry indeed feels very strongly that it is not getting from ESA the support it needs to match the performance of its foreign competitors on the world markets. It can only succeed commercially in the fierce competition with the U.S. and Japan if a substantial R&D program is defined and funded at European level, as required by the magnitude of the financial effort necessary. It is concluded that anything the agency untertakes in the future to redress the situation would produce much greater dividends if it were part of a coherent plan where all the European partners play their role in a cooperative spirit. It is recommended that the European Commission should, as a matter of urgency, take steps to institute a concertation mechanism involving all major players with a view to defining and developing a coherent strategy for Europe.

Modern Social Media and Social Revolutions

Science.gov (United States)

2011-12-16

another part of the world is equally presented on the event domain and observable by the social revolution domain. Engagements work as the linkage...MODERN SOCIAL MEDIA AND SOCIAL REVOLUTIONS A thesis presented to the Faculty of the U.S. Army Command and General Staff College in...MM-YYYY) 16-12-2011 2. REPORT TYPE Master’s Thesis 3. DATES COVERED (From - To) FEB 2011 – DEC 2011 4. TITLE AND SUBTITLE Modern Social

Fiber optical sensing on-board communication satellites

Science.gov (United States)

Hurni, A.; Lemke, N. M. K.; Roner, M.; Obermaier, J.; Putzer, P.; Kuhenuri Chami, N.

2017-11-01

Striving constantly to reduce mass, AIT effort and overall cost of the classical point-to-point wired temperature sensor harness on-board telecommunication satellites, OHB System (formerly Kayser-Threde) has introduced the Hybrid Sensor Bus (HSB) system. As a future spacecraft platform element, HSB relies on electrical remote sensor units as well as fiber-optical sensors, both of which can serially be connected in a bus architecture. HSB is a modular measurement system with many applications, also thanks to the opportunities posed by the digital I²C bus. The emphasis, however, is on the introduction of fiber optics and especially fiber-Bragg grating (FBG) temperature sensors as disruptive innovation for the company's satellite platforms. The light weight FBG sensors are directly inscribed in mechanically robust and radiation tolerant fibers, reducing the need for optical fiber connectors and splices to a minimum. Wherever an FBG sensor shall be used, the fiber is glued together with a corresponding temperature transducer to the satellites structure or to a subsystem. The transducer is necessary to provide decoupling of mechanical stress, but simultaneously ensure a high thermal conductivity. HSB has been developed in the frame of an ESA-ARTES program with European and German co-funding and will be verified as flight demonstrator on-board the German Heinrich Hertz satellite (H2Sat). In this paper the Engineering Model development of HSB is presented and a Fiber-optical Sensor Multiplexer for a more flexible sensor bus architecture is introduced. The HSB system aims at telecommunication satellite platforms with an operational life time beyond 15 years in geostationary orbit. It claims a high compatibility in terms of performance and interfaces with existing platforms while it was designed with future applications with increased radiation exposure already in mind. In its basic configuration HSB consists of four modules which are the Power Supply Unit, the HSB

Advanced Communication Technology Satellite (ACTS) Multibeam Antenna On-Orbit Performance

Science.gov (United States)

1995-01-01

The NASA Lewis Research Center's Advanced Communication Technology Satellite (ACTS) was launched in September 1993. ACTS introduced several new technologies, including a multibeam antenna (MBA) operating at extremely short wavelengths never before used in communications. This antenna, which has both fixed and rapidly reconfigurable high-energy spot beams (150 miles in diameter), serves users equipped with small antenna terminals. Extensive structural and thermal analyses have been performed for simulating the ACTS MBA on-orbit performance. The results show that the reflector surfaces (mainly the front subreflector), antenna support assembly, and metallic surfaces on the spacecraft body will be distorted because of the thermal effects of varying solar heating, which degrade the ACTS MBA performance. Since ACTS was launched, a number of evaluations have been performed to assess MBA performance in the space environment. For example, the on-orbit performance measurements found systematic environmental disturbances to the MBA beam pointing. These disturbances were found to be imposed by the attitude control system, antenna and spacecraft mechanical alignments, and on-orbit thermal effects. As a result, the MBA may not always exactly cover the intended service area. In addition, the on-orbit measurements showed that antenna pointing accuracy is the performance parameter most sensitive to thermal distortions on the front subreflector surface and antenna support assemblies. Several compensation approaches were tested and evaluated to restore on-orbit pointing stability. A combination of autotrack (75 percent of the time) and Earth sensor control (25 percent of the time) was found to be the best way to compensate for antenna pointing error during orbit. This approach greatly minimizes the effects of thermal distortions on antenna beam pointing.

Walking through the Revolution: A Spatial Reading of Literary Echoes

Science.gov (United States)

Queiroz, Ana Isabel; Alves, Daniel

2015-01-01

This paper presents an embryo of a literary guide on the Carnation Revolution to be explored for educational historical excursions other than leisure and tourism. We propose a historical trail through the centre of Lisbon, city of the Carnation Revolution, called "Walk through the Revolution." The trail aims to reinforce collective…

Development and Analysis of Image Registration Program for the Communication, Ocean, Meteorological Satellite (COMS

Directory of Open Access Journals (Sweden)

Un-Seob Lee

2007-09-01

Full Text Available We developed a software for simulations and analyses of the Image Navigation and Registration (INR system, and compares the characteristics of Image Motion Compensation (IMC algorithms for the INR system. According to the orbit errors and attitude errors, the capabilities of the image distortions are analyzed. The distortions of images can be compensated by GOES IMC algorithm and Modified IMC (MIMC algorithm. The capabilities of each IMC algorithm are confirmed based on compensated images. The MIMC yields better results than GOES IMC although both the algorithms well compensate distorted images. The results of this research can be used as valuable asset to design of INR system for the Communication, Ocean, Meteorological Satellite (COMS.

47 CFR 25.148 - Licensing provisions for the Direct Broadcast Satellite Service.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Licensing provisions for the Direct Broadcast Satellite Service. 25.148 Section 25.148 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses Space Stations § 25.148...

47 CFR 25.211 - Analog video transmissions in the Fixed-Satellite Services.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Analog video transmissions in the Fixed-Satellite Services. 25.211 Section 25.211 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Standards § 25.211 Analog video transmissions...

The Cultural Revolution and Contemporary Chinese Art

Science.gov (United States)

Yang, Guey-Meei; Suchan, Tom

2009-01-01

Using this instructional resource, teachers can explore the impact of the Cultural Revolution (1966-1976) on contemporary art in mainland China with their students. The three artists Luo Zhongli (b. 1948), Xu Bing (b. 1955), and Wang Guangyi (b. 1957) came of age during the Cultural Revolution and are representative of a much larger number of…

Military Revolution, Organisational Revolutions...and Other Revolutions

DEFF Research Database (Denmark)

Harste, Gorm

  This paper is a continuation of Kantian peace and war analysis, but with other means. The paper is part of an effort to establish a systemic theory of state-formation based on the description of the emergence of a number of functional systems. In a historical perspective the military system...... was dominant in the establishment of the European State-model as well as it has a decisive role in the stabilisation of recent states. Using Niklas Luhmann's system theory that does not describes neither military systems nor the emergence of a organisational system, the present paper outlines a system...... theoretical perspective on the present and historical transformations of military systems. One the one hand the paper offers a systemic criticism of the recent so called revolution in military affairs (RMA), on the other hand the historical establishment of a self-referential form of the military system...

The next generation of Palapa satellite (Palapa-C)

Science.gov (United States)

Setiawan, Bambang

The Indonesian Palapa Communication Satellite System was established in Aug. 1976 when the first satellite of Palapa A series (Palapa A1) began operation. The system is owned and operated by PT. Telekomunikasi Indonesia (Telkom), which is a state owned company. The purpose of the system was to unify the telecommunications of the nation. Many years of operation have shown that satellite technology is the best solution for improving telecommunications in Indonesia. The system was started with 2 (two) satellites, each with 12 transponders (for a total of 24), and 40 earth stations. Now the system has 3 (three) satellites, each with 24 transponders (for a total of 72 transponders), and thousands of earth stations. The services have been extended to satisfy the requirements of the region as well as the original objectives. The use of satellite transponders in the region is increasing rapidly. In the next ten years, opportunities in the satellite communications business will become even more attractive. The next generation Palapa-C will incorporate improvements in capacity, quality, and coverage. The new frequency bands (ku- and Extended-C Band) will be used to meet the new transponder capacity requirements.

The design and networking of dynamic satellite constellations for global mobile communication systems

Science.gov (United States)

Cullen, Cionaith J.; Benedicto, Xavier; Tafazolli, Rahim; Evans, Barry

1993-01-01

Various design factors for mobile satellite systems, whose aim is to provide worldwide voice and data communications to users with hand-held terminals, are examined. Two network segments are identified - the ground segment (GS) and the space segment (SS) - and are seen to be highly dependent on each other. The overall architecture must therefore be adapted to both of these segments, rather than each being optimized according to its own criteria. Terrestrial networks are grouped and called the terrestrial segment (TS). In the SS, of fundamental importance is the constellation altitude. The effect of the altitude on decisions such as constellation design choice and on network aspects like call handover statistics are fundamental. Orbit resonance is introduced and referred to throughout. It is specifically examined for its useful properties relating to GS/SS connectivities.

TETRA Backhauling via Satellite: Improving Call Setup Times and Saving Bandwidth

Directory of Open Access Journals (Sweden)

Anton Donner

2014-01-01

Full Text Available In disaster management scenarios with seriously damaged, not existing, or saturated communication infrastructures satellite communications can be an ideal means to provide connectivity with unaffected remote terrestrial trunked radio (TETRA core networks. However, the propagation delay imposed by the satellite link affects the signalling protocols. This paper discusses the suitability of using a satellite link for TETRA backhauling, introducing two different architectures. In order to cope with the signal delay of the satellite link, the paper proposes and analyzes a suitable solution based on the use of a performance enhancing proxy (PEP. Additionally, robust header compression (ROHC is discussed as suitable technology to transmit TETRA voice via IP-based satellite networks.

Future of wireless communication

Energy Technology Data Exchange (ETDEWEB)

Barker, M

1996-12-31

This document reproduces slides from a conference presentation giving an overview of current and upcoming wireless communication methods of interest to Canadian electric utilities. Both voice and data communication methods are considered, including cellular telephone, satellite communications, personal communication services, regulated licensed arrowband data systems, and integrated services.

The Use of a Satellite Communications System for Command and Control of the National Aeronautics and Space Administration Surrogate Unmanned Aerial System Research Aircraft

Science.gov (United States)

Howell, Charles T.; Jones, Frank; Hutchinson, Brian; Joyce, Claude; Nelson, Skip; Melum, Mike

2017-01-01

The NASA Langley Research Center has transformed a Cirrus Design SR22 general aviation (GA) aircraft into an Unmanned Aerial Systems (UAS) Surrogate research aircraft which has served for several years as a platform for unmanned systems research and development. The aircraft is manned with a Safety Pilot and a Research Systems Operator (RSO) that allows for flight operations almost any-where in the national airspace system (NAS) without the need for a Federal Aviation Administration (FAA) Certificate of Authorization (COA). The UAS Surrogate can be remotely controlled from a modular, transportable ground control station (GCS) like a true UAS. Ground control of the aircraft is accomplished by the use of data links that allow the two-way passage of the required data to control the aircraft and provide the GCS with situational awareness. The original UAS Surrogate data-link system was composed of redundant very high frequency (VHF) data radio modems with a maximum range of approximately 40 nautical miles. A new requirement was developed to extend this range beyond visual range (BVR). This new requirement led to the development of a satellite communications system that provided the means to command and control the UAS Surrogate at ranges beyond the limits of the VHF data links. The system makes use of the Globalstar low earth orbit (LEO) satellite communications system. This paper will provide details of the development, implementation, and flight testing of the satellite data communications system on the UAS Surrogate research aircraft.

The Whiteboard Revolution: Illuminating Science Communication in the Digital Age.

Science.gov (United States)

Mar, Florie Anne; Ordovas-Montanes, Jose; Oksenberg, Nir; Olson, Alexander M

2016-04-01

Journal-based science communication is not accessible or comprehensible to a general public curious about science and eager for the next wave of scientific innovation. We propose an alternative medium for scientists to communicate their work to the general public in an engaging and digestible way through the use of whiteboard videos. We describe the process of producing science whiteboard videos and the benefits and challenges therein. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Next Revolution

Science.gov (United States)

Bell, Carolyn Shaw

1975-01-01

The future status of women is envisioned as more than labor market projections of wider employment opportunities. Responsibilities of human beings such as family formation, upbringing of children, the process of human growth and development, marriage and divorce are seen as components of the second revolution. (Author/AM)

Den moderate revolution

DEFF Research Database (Denmark)

Larsen, Bøje

"normale" industrivirksomheder, men den er absolut set begrænset. Årsagerne til denne kun "moderate revolution" af organisationsformerne diskuteres: Er det fordi klassisk organisation og social nærkontakt er nødvendig i den nye økonomi, eller er det manglende fantasi og tryghedsbehov? Begge muligheder...

Handbook of satellite applications

CERN Document Server

Madry, Scott; Camacho-Lara, Sergio

2013-01-01

Top space experts from around the world have collaborated to produce this comprehensive, authoritative, and clearly illustrated reference guide to the fast growing, multi-billion dollar field of satellite applications and space communications. This handbook, done under the auspices of the International Space University based in France, addresses not only system technologies but also examines market dynamics, technical standards and regulatory constraints. The handbook is a completely multi-disciplinary reference book that covers, in an in-depth fashion, the fields of satellite telecommunications, Earth observation, remote sensing, satellite navigation, geographical information systems, and geosynchronous meteorological systems. It covers current practices and designs as well as advanced concepts and future systems. It provides a comparative analysis of the common technologies and design elements for satellite application bus structures, thermal controls, power systems, stabilization techniques, telemetry, com...

Relative tracking control of constellation satellites considering inter-satellite link

Science.gov (United States)

Fakoor, M.; Amozegary, F.; Bakhtiari, M.; Daneshjou, K.

2017-11-01

In this article, two main issues related to the large-scale relative motion of satellites in the constellation are investigated to establish the Inter Satellite Link (ISL) which means the dynamic and control problems. In the section related to dynamic problems, a detailed and effective analytical solution is initially provided for the problem of satellite relative motion considering perturbations. The direct geometric method utilizing spherical coordinates is employed to achieve this solution. The evaluation of simulation shows that the solution obtained from the geometric method calculates the relative motion of the satellite with high accuracy. Thus, the proposed analytical solution will be applicable and effective. In the section related to control problems, the relative tracking control system between two satellites will be designed in order to establish a communication link between the satellites utilizing analytical solution for relative motion of satellites with respect to the reference trajectory. Sliding mode control approach is employed to develop the relative tracking control system for body to body and payload to payload tracking control. Efficiency of sliding mode control approach is compared with PID and LQR controllers. Two types of payload to payload tracking control considering with and without payload degree of freedom are designed and suitable one for practical ISL applications is introduced. Also, Fuzzy controller is utilized to eliminate the control input in the sliding mode controller.

Real-time monitoring of seismic data using satellite telemetry

Directory of Open Access Journals (Sweden)

L. Merucci

1997-06-01

Full Text Available This article describes the ARGO Satellite Seismic Network (ARGO SSN as a reliable system for monitoring, collection, visualisation and analysis of seismic and geophysical low-frequency data, The satellite digital telemetry system is composed of peripheral geophysical stations, a centraI communications node (master sta- tion located in CentraI Italy, and a data collection and processing centre located at ING (Istituto Nazionale di Geofisica, Rome. The task of the peripheral stations is to digitalise and send via satellite the geophysical data collected by the various sensors to the master station. The master station receives the data and forwards them via satellite to the ING in Rome; it also performs alI the monitoring functions of satellite communications. At the data collection and processing centre of ING, the data are received and analysed in real time, the seismic events are identified and recorded, the low-frequency geophysical data are stored. In addition, the generaI sta- tus of the satellite network and of each peripheral station connected, is monitored. The procedure for analysjs of acquired seismic signals allows the automatic calculation of local magnitude and duration magnitude The communication and data exchange between the seismic networks of Greece, Spain and Italy is the fruit of a recent development in the field of technology of satellite transmission of ARGO SSN (project of European Community "Southern Europe Network for Analysis of Seismic Data"

The synchronization method for distributed small satellite SAR

Science.gov (United States)

Xing, Lei; Gong, Xiaochun; Qiu, Wenxun; Sun, Zhaowei

2007-11-01

One of critical requirement for distributed small satellite SAR is the trigger time precision when all satellites turning on radar loads. This trigger operation is controlled by a dedicated communication tool or GPS system. In this paper a hardware platform is proposed which has integrated navigation, attitude control, and data handling system together. Based on it, a probabilistic synchronization method is proposed for SAR time precision requirement with ring architecture. To simplify design of transceiver, half-duplex communication way is used in this method. Research shows that time precision is relevant to relative frequency drift rate, satellite number, retry times, read error and round delay length. Installed with crystal oscillator short-term stability 10 -11 magnitude, this platform can achieve and maintain nanosecond order time error with a typical three satellites formation experiment during whole operating process.

Communication-based positioning systems: past, present and prospects

International Nuclear Information System (INIS)

Ma Guanyi; Wan Qingtao; Gan Tong

2012-01-01

This paper reviews positioning systems in the context of communication systems. First, the basic positioning technique is described for location based service (LBS) in mobile communication systems. Then the high integrity global positioning system (iGPS) is introduced in terms of aspects of what it is and how the low Earth orbit (LEO) Iridium telecommunication satellites enhance the global positioning system (GPS). Emphasis is on the Chinese Area Positioning System (CAPS) which is mainly based on commercial geostationary (GEO) communication satellites, including decommissioned GEO and inclined geosynchronous communication satellites. Characterized by its low cost, high flexibility, wide-area coverage and ample frequency resources, a distinctive feature of CAPS is that its navigation messages are generated on the ground, then uploaded to and forwarded by the communication satellites. Fundamental principles and key technologies applied in the construction of CAPS are presented in detail from the CAPS validation phase to its experimental system setup. A prospective view of CAPS has concluded it to be a seamless, high accuracy, large capacity navigation and communication system which can be achieved by expanding it world wide and enhancing it with LEO satellites and mobile base stations. Hence, this system is a potential candidate for the next generation of radio navigation after GPS. (invited reviews)

On the revolution of heavenly spheres

CERN Document Server

Copernicus, Nicolaus

1995-01-01

The Ptolemaic system of the universe, with the earth at the center, had held sway since antiquity as authoritative in philosophy, science, and church teaching. Following his observations of the heavenly bodies, Nicolaus Copernicus (1473-1543) abandoned the geocentric system for a heliocentric model, with the sun at the center. His remarkable work, On the Revolutions of Heavenly Spheres, stands as one of the greatest intellectual revolutions of all time, and profoundly influenced, among others, Galileo and Sir Isaac Newton.

Crisis Communication and Social

DEFF Research Database (Denmark)

Tække, Jesper

2017-01-01

The academic field of crisis communication is more relevant than ever due to the digital media revolution, setting new standards for how to manage criticism and crises. This paper presents a systems theoretical approach to crisis communication in the age of digital media with a special regard...... to social media. The paper shows that the recent changes in the media environment require that organizations be more observant, reflected and responsive to the public opinion. Correspondingly, organizations need to engage in strategic impression management with the aim to be, or to be observed to be, more...... consistent with their communicated values and strategies, thus managing to appear as trustworthy in a hyper-dynamic social surrounding world. Copyright © 2017 John Wiley & Sons, Ltd....

Satellite Telecommunications in Education: An Overview of Related Organizations and Activities.

Science.gov (United States)

Schneller, Paul

An overview is presented of the organizations, institutions, and projects involved in the educational use of satellite communications. This paper is intended for use as a reference tool for educators rather than a means to discuss the implications of satellite communications for individuals and society. A description of the major components of…

The 'Shale Gas Revolution'. Hype and Reality

International Nuclear Information System (INIS)

Stevens, P.

2010-09-01

The 'shale gas revolution' - responsible for a huge increase in unconventional gas production in the US over the last couple of years - is creating huge investor uncertainties for international gas markets and renewables and could result in serious gas shortages in 10 years time. This report casts serious doubt over industry confidence in the 'revolution', questioning whether it can spread beyond the US, or indeed be maintained within it, as environmental concerns, high depletion rates and the fear that US circumstances may be impossible to replicate elsewhere, come to the fore. Investor uncertainty will reduce investment in future gas supplies to lower levels than would have happened had the 'shale gas revolution' not hit the headlines. While the markets will eventually solve this problem, rising gas demand and the long lead-in-times on most gas projects are likely to inflict high prices on consumers in the medium term. The uncertainties created by the 'shale gas revolution' are also likely to compound existing investor uncertainty in renewables for power generation in the aftermath of Copenhagen. The serious possibility of cheap, relatively clean gas may threaten investment in more expensive lower carbon technologies.

Future Legacy of the Russian Revolution. Participatory Political Economies

Czech Academy of Sciences Publication Activity Database

Hrubec, Marek

2017-01-01

Roč. 7, č. 4 (2017), s. 565-580 ISSN 2159-8282 Institutional support: RVO:67985955 Keywords : revolution * participation * political economy * Russian revolution Subject RIV: AA - Philosophy ; Religion OBOR OECD: Political science

Hacking the quantum revolution: 1925-1975

Science.gov (United States)

Schweber, Silvan S.

2015-01-01

I argue that the quantum revolution should be seen as an Ian Hacking type of scientific revolution: a profound, longue durée, multidisciplinary process of transforming our understanding of physical nature, with deep-rooted social components from the start. The "revolution" exhibits a characteristic style of reasoning - the hierarchization of physical nature - and developed and uses a specific language - quantum field theory (QFT). It is by virtue of that language that the quantum theory has achieved some of its deepest insights into the description of the dynamics of the physical world. However, the meaning of what a quantum field theory is and what it describes has deeply altered, and one now speaks of "effective" quantum field theories. Interpreting all present day quantum field theories as but "effective" field theories sheds additional light on Phillip Anderson's assertion that "More is different". This important element is addressed in the last part of the paper.

Revolution in nuclear detection affairs

International Nuclear Information System (INIS)

Stern, Warren M.

2014-01-01

The detection of nuclear or radioactive materials for homeland or national security purposes is inherently difficult. This is one reason detection efforts must be seen as just one part of an overall nuclear defense strategy which includes, inter alia, material security, detection, interdiction, consequence management and recovery. Nevertheless, one could argue that there has been a revolution in detection affairs in the past several decades as the innovative application of new technology has changed the character and conduct of detection operations. This revolution will likely be most effectively reinforced in the coming decades with the networking of detectors and innovative application of anomaly detection algorithms

Public Diplomacy and the Clash of Satellites

OpenAIRE

Marwa Fikry Abdel Samei

2016-01-01

The communication revolution has shifted the paradigm of diplomacy by emphasizing the role of public diplomacy, at the same time complicating the environment within which state-managed public diplomacy is conducted. The rise of regional media has provided weaker states with opportunities to challenge the monopoly of information on the part of the more powerful states. Al-Hurra, the American sponsored channel to the Arab World, stands as evidence of the challenges facing US policies in thi...

Citizen's protests in times of energy revolution

International Nuclear Information System (INIS)

Hoeft, Christoph; Messinger-Zimmer, Soeren; Zilles, Julia

2017-01-01

Part A covers the German energy revolution as socio-scientific research field. Part B deals with local conflicts concerning energy revolution projects - inspections: protests against transmission line location, protests against wind mills, protests against fracking. Part C includes contributions on participants and non-involved people - perception and perspectives: the conflicts in the view of different groups. Part D summarizes the protests and concludes with nine hypotheses.

Economic Motives Behind the 2011 Egyptian Revolution

Science.gov (United States)

2014-09-01

from below,”8 attaching revolutions to a combination of several conflicts between state, bourgeoisies , and the lower class. She also states...of France , Russia, and China (New York: Cambridge University Press, 1979), 4. 9 Theda Skocpol, “ France , Russia, China: A Structural Analysis of...Social Revolutions: A Comparative Analysis of France , Russia, and China. New York: Cambridge University Press, 1979. Soliman, Ibrahim, and Shahla

SDI satellite autonomy using AI and Ada

Science.gov (United States)

Fiala, Harvey E.

1990-01-01

The use of Artificial Intelligence (AI) and the programming language Ada to help a satellite recover from selected failures that could lead to mission failure are described. An unmanned satellite will have a separate AI subsystem running in parallel with the normal satellite subsystems. A satellite monitoring subsystem (SMS), under the control of a blackboard system, will continuously monitor selected satellite subsystems to become alert to any actual or potential problems. In the case of loss of communications with the earth or the home base, the satellite will go into a survival mode to reestablish communications with the earth. The use of an AI subsystem in this manner would have avoided the tragic loss of the two recent Soviet probes that were sent to investigate the planet Mars and its moons. The blackboard system works in conjunction with an SMS and a reconfiguration control subsystem (RCS). It can be shown to be an effective way for one central control subsystem to monitor and coordinate the activities and loads of many interacting subsystems that may or may not contain redundant and/or fault-tolerant elements. The blackboard system will be coded in Ada using tools such as the ABLE development system and the Ada Production system.

Heterogeneous Networks for the IoT and Machine Type Communications

OpenAIRE

Abrignani, Melchiorre Danilo

2016-01-01

The Internet of Things promises to be a key-factor in the forthcoming industrial and social revolution. The Internet of Things concept rely on pervasive communications where ’things’ are ’always connected’. The focus of the thesis is on Heterogeneous Networks for Internet of Things and Machine Type Communications. Heterogeneous Networks are an enabling factor of paramount important in order to achieve the ’always connected’ paradigm. On the other hand, Machine Type Communications are deeply d...

Investigation of multipactor breakdown in communication satellite microwave co-axial systems

Science.gov (United States)

Nagesh, S. K.; Revannasiddiah, D.; Shastry, S. V. K.

2005-01-01

Multipactor breakdown or multipactor discharge is a form of high frequency discharge that may occur in microwave components operating at very low pressures. Some RF components of multi-channel communication satellites have co-axial geometry and handle high RF power under near-vacuum conditions. The breakdown occurs due to secondary electron resonance, wherein electrons move back and forth in synchronism with the RF voltage across the gap between the inner and outer conductors of the co-axial structure. If the yield of secondary electrons from the walls of the co-axial structure is greater than unity, then the electron density increases with time and eventually leads to the breakdown. In this paper, the current due to the oscillating electrons in the co-axial geometry has been treated as a radially oriented Hertzian dipole. The electric field, due to this dipole, at any point in the coaxial structure, may then be determined by employing the dyadic Green's function technique. This field has been compared with the field that would exist in the absence of multipactor.

The Demographic Revolution: Reconceptualizing Macroeconomics

Directory of Open Access Journals (Sweden)

Orio Giarini

2013-05-01

Full Text Available It is important to reconsider the measurements which refer to the “Wealth of Nations” and from which the most appropriate references for better welfare policies are derived. In the present Service Economy, not all the “value added” measures indicate an increase in the level of wealth (the costs to cope with pollution for instance, whereas many developments in service functions and performances (in the case of many communication systems for instance add to real wealth much more than the usual value added references indicate. In particular, the notion of productivity in a Service economy is much more relevant with reference to performance in time (hence in a probabilistic system than to the production factor costs (in an equilibrium-based system. But all this is linked to progress in economics as a discipline, and to its integration with environmental issues (which also pretend to solve the problems of the “Wealth of Nations” on the basis of their “sustainability”. This will be a new era in economic development which will be beyond current extrapolations and will hope for “growth” in the traditional Industrial Revolution perspective.

Teaching Graphics in Technical Communication Classes.

Science.gov (United States)

Spurgeon, Kristene C.

Perhaps because the United States is undergoing a video revolution, perhaps because of its increasing sales of goods to non-English speaking markets where graphics can help explain the products, perhaps because of the decreasing communication skills of the work force, graphic aids are becoming more and more widely used and more and more important.…

Communications Satellite Receiver Systems for Public Schools: A Technical Primer.

Science.gov (United States)

Texas Education Agency, Austin.

Designed to aid school districts contemplating use of some of the telecommunications services now available by satellite, this document contains information on home satellite receiving dishes (Television Receive-Only--TVROs), which can receive radio signals carrying television, sound, and data. This information includes: some factors involved in…

21st Century Socialism: Making a State for Revolution

Directory of Open Access Journals (Sweden)

Lee Artz

2012-05-01

Full Text Available The Bolivarian Revolution in Venezuela has built mass organizations of workers and communities that have erratically challenged class and market relations—verifying that taking political power is difficult but essential to fundamental social change and that capitalist cultural practices complicate the revolutionary process. This work identifies components of state power, separating state apparatus (government as a crucial site for instituting social change. The case of democratic, participatory communication and public media access is presented as central to the successes and problems of Venezuelan 21st century socialism. Drawing on field research in community media in Caracas, the essay highlights some of the politico-cultural challenges and class contradictions in producing and distributing cultural values and social practices for a new socialist hegemony necessary for fundamental social change.

THE INDUSTRIAL ENGINEER: CAUGHT BETWEEN TWO REVOLUTIONS?

OpenAIRE

Niek Du Preez; Liliane Pintelon

2012-01-01

The .Industrial Engineer is caught between the Industrial Revolution and the Information revolution. He is confronted with choosing between pragmatic improvements in productivity and efficiency of a single operation or the opportunistic modelling and reshaping of the networked "virtual enterprise" to become more competitive in a global marketplace . The diagram below depicts the different extremes of the Industrial Engineering timeline. This implies that the two societies (Industrial and info...

Mobile Communication, Public Participation and E-Governance in China

DEFF Research Database (Denmark)