WorldWideScience

Sample records for satellite communications technologies

  1. Satellite communication antenna technology

    Science.gov (United States)

    Mittra, R. (Editor); Imbriale, W. A. (Editor); Maanders, E. J. (Editor)

    1983-01-01

    A general overview of current technology in the field of communication satellite antennas is presented. Among the topics discussed are: the design of multiple beam systems; frequency reuse; and polarization control of antenna measurements. Consideration is also given to: contour beam synthesis; dual shaped reflector synthesis; beam shaping; and offset reflector design. The applications of the above technologies to present and future generations of communications satellites is considered, with emphasis given to such systems as: the Intelsats; the Defense Satellite Communications System, (DSCS-III); Satellite Business System (SBS), and Comstar.

  2. Communication satellite technology trends

    Science.gov (United States)

    Cuccia, Louis

    1986-01-01

    A chronology of space-Earth interconnectivity is presented. The Advanced Communications Technology Satellite (ACTS) system, Land Mobile Satellite, space-Earth antennas, impact of antenna size on coverage, intersatellite links are outlined. This presentation is represented by graphs and charts only.

  3. Advanced Communications Technology Satellite (ACTS)

    Science.gov (United States)

    Gedney, Richard T.; Schertler, Ronald J.

    1989-01-01

    The NASA Advanced Communications Technology Satellite (ACTS) was conceived to help maintain U.S. leadership in the world's communications-satellite market. This experimental satellite is expected to be launched by NASA in 1992 and to furnish the technology necessary for establishing very small aperture terminal digital networks which provide on-demand full-mesh connectivity, and 1.544-MBPS services with only a single hop. Utilizing on-board switching and processing, each individual voice or data circuit can be separately routed to any location in the network. This paper provides an overview of the ACTS and discusses the value of the technology for future communications systems.

  4. Advanced Communications Technology Satellite (ACTS)

    Science.gov (United States)

    Olmstead, Dean A.; Schertler, Ronald J.

    The benefits that will be offered by the NASA-sponsored communication spacecraft ACTS which is scheduled for launch in 1992 are described together with examples of demonstrations on proposed data, video, and voice applications supported by the advanced ACTS technologies. Compared to existing satellite service, the ACTS will provide lower cost, better service, greater convenience, and improved service reliability of telecommunications to customers around the world. In addition, the pioneering ACTS technology will provide many capabilities qualitatively different from those of current satellite systems, such as on-demand assignment, frequency reuse, and the flexible targeting of spot beams directly to the very-small-aperture terminals at customer premises.

  5. Research Supporting Satellite Communications Technology

    Science.gov (United States)

    Horan Stephen; Lyman, Raphael

    2005-01-01

    This report describes the second year of research effort under the grant Research Supporting Satellite Communications Technology. The research program consists of two major projects: Fault Tolerant Link Establishment and the design of an Auto-Configurable Receiver. The Fault Tolerant Link Establishment protocol is being developed to assist the designers of satellite clusters to manage the inter-satellite communications. During this second year, the basic protocol design was validated with an extensive testing program. After this testing was completed, a channel error model was added to the protocol to permit the effects of channel errors to be measured. This error generation was used to test the effects of channel errors on Heartbeat and Token message passing. The C-language source code for the protocol modules was delivered to Goddard Space Flight Center for integration with the GSFC testbed. The need for a receiver autoconfiguration capability arises when a satellite-to-ground transmission is interrupted due to an unexpected event, the satellite transponder may reset to an unknown state and begin transmitting in a new mode. During Year 2, we completed testing of these algorithms when noise-induced bit errors were introduced. We also developed and tested an algorithm for estimating the data rate, assuming an NRZ-formatted signal corrupted with additive white Gaussian noise, and we took initial steps in integrating both algorithms into the SDR test bed at GSFC.

  6. Introduction to Satellite Communications Technology for NREN

    Science.gov (United States)

    Stone, Thom

    2004-01-01

    NREN requirements for development of seamless nomadic networks necessitates that NREN staff have a working knowledge of basic satellite technology. This paper addresses the components required for a satellite-based communications system, applications, technology trends, orbits, and spectrum, and hopefully will afford the reader an end-to-end picture of this important technology.

  7. An Educator's Guide to Communication Satellite Technology.

    Science.gov (United States)

    Polcyn, Kenneth A.

    Recent developments in the area of sophisticated communications technology present challenges to the imagination of every educator. This guide provides educational planners with an awareness and understanding of communication satellite technology, its current uses, and some of the tentative plans for educational experimentation. The first part…

  8. 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.

  9. The Communications Technology Satellite /CTS/ Program

    Science.gov (United States)

    Evans, W. M.; Davies, N. G.; Hawersaat, W. H.

    1976-01-01

    The purposes of the joint Canadian-U.S. Communications Technology Satellite (CTS) Program are (1) to conduct satellite communication systems experiments using the 12- and 14-GHz bands and low-cost transportable ground terminals, (2) to develop and flight test a power amplifier tube having a greater than 50% efficiency with a saturated power output of 200 W at 12 GHz, (3) to develop and flight test a lightweight extendible solar array with an initial power output greater than 1 kW, and (4) to develop and flight test a 3-axis stabilization system to maintain accurate antenna boresight positioning on a spacecraft with flexible appendages. Brief descriptions of these experiments and of the ground facilities are provided.

  10. 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.

  11. 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.).

  12. 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.

  13. The role of technology in influencing future civil communications satellites

    Science.gov (United States)

    Bagwell, James W.; Mahle, Christoph E.

    1990-01-01

    Technology, both as an enabler and as a driver of new and improved communication satellites, is discussed. A brief look at the beginnings and evolution of satellite communications is given to reveal the continuing influence of technology over the past 25 years. An assessment of the current state of the art which serves as a benchmark representing how far technology has come and as a basis for comparison for future possibilities is presented. A short tutorial on communications satellite basics is presented, followed by an assessment of technologies used for satellite antennas and signal amplification and routing. A discussion of future service requirements follows, and emerging technologies are identified along with possible improved communications capabilities that can result from them. The outlook for the role of technology for future communication satellites is summarized.

  14. Mobile satellite communications - Vehicle antenna technology update

    Science.gov (United States)

    Bell, D.; Naderi, F. M.

    1986-01-01

    This paper discusses options for vehicle antennas to be used in mobile satellite communications systems. Two types of antennas are identified. A non-steerable, azimuthally omnidirectional antenna with a modest gain of 3 to 5 dBi is suggested when a low cost is desired. Alternatively, mechanically or electronically steerable antennas with a higher gain of 10 to 12 dBi are suggested to alleviate power and spectrum scarcity associated with mobile satellite communications. For steerable antennas, both open-loop and closed-loop pointing schemes are discussed. Monopulse and sequential lobing are proposed for the mechanically steered and electronically steered antennas, respectively. This paper suggests a hybrid open-loop/closed-loop pointing technique as the best performer in the mobile satellite environment.

  15. Multichannel demultiplexer/demodulator technologies for future satellite communication systems

    Science.gov (United States)

    Ivancic, William D.; Budinger, James M.; Staples, Edward J.; Abramovitz, Irwin; Courtois, Hector A.

    1992-01-01

    NASA-Lewis' Space Electronics Div. supports ongoing research in advanced satellite communication architectures, onboard processing, and technology development. Recent studies indicate that meshed VSAT (very small aperture terminal) satellite communication networks using FDMA (frequency division multiple access) uplinks and TDMA (time division multiplexed) downlinks are required to meet future communication needs. One of the critical advancements in such a satellite communication network is the multichannel demultiplexer/demodulator (MCDD). The progress is described which was made in MCDD development using either acousto-optical, optical, or digital technologies.

  16. Satellite Communications

    CERN Document Server

    Pelton, Joseph N

    2012-01-01

    The field of satellite communications represents the world's largest space industry. Those who are interested in space need to understand the fundamentals of satellite communications, its technology, operation, business, economic, and regulatory aspects. This book explains all this along with key insights into the field's future growth trends and current strategic challenges. Fundamentals of Satellite Communications is a concise book that gives all of the key facts and figures as well as a strategic view of where this dynamic industry is going. Author Joseph N. Pelton, PhD, former Dean of the International Space University and former Director of Strategic Policy at Intelstat, presents a r

  17. Satellite Communication.

    Science.gov (United States)

    Technology Teacher, 1985

    1985-01-01

    Presents a discussion of communication satellites: explains the principles of satellite communication, describes examples of how governments and industries are currently applying communication satellites, analyzes issues confronting satellite communication, links mathematics and science to the study of satellite communication, and applies…

  18. An overview of the Communications Technology Satellite (CTS) project

    Science.gov (United States)

    Rapp, W.; Ogden, D.; Wright, D.

    1982-01-01

    The Communications Technology Satellite (CTS) project is reviewed. A technical description of the CTS spacecraft and its cognate hardware and operations is included. A historical treatise of the CTS project is provided. Also presented is an overview of the CTS experiments and demonstrations conducted during the course of the project.

  19. Communications technology satellite output-tube design and development

    Science.gov (United States)

    Connolly, D. J.; Forman, R.; Jones, C. L.; Kosmahl, H.; Sharp, G. R.

    1977-01-01

    The design and development of a 200-watt-output, traveling-wave tube (TWT) for the Communications Technology Satellite (CTS) is discussed, with emphasis on the design evolution during the manufacturing phase of the development program. Possible further improvements to the tube design are identified.

  20. NASA's mobile satellite communications program; ground and space segment technologies

    Science.gov (United States)

    Naderi, F.; Weber, W. J.; Knouse, G. H.

    1984-10-01

    This paper describes the Mobile Satellite Communications Program of the United States National Aeronautics and Space Administration (NASA). The program's objectives are to facilitate the deployment of the first generation commercial mobile satellite by the private sector, and to technologically enable future generations by developing advanced and high risk ground and space segment technologies. These technologies are aimed at mitigating severe shortages of spectrum, orbital slot, and spacecraft EIRP which are expected to plague the high capacity mobile satellite systems of the future. After a brief introduction of the concept of mobile satellite systems and their expected evolution, this paper outlines the critical ground and space segment technologies. Next, the Mobile Satellite Experiment (MSAT-X) is described. MSAT-X is the framework through which NASA will develop advanced ground segment technologies. An approach is outlined for the development of conformal vehicle antennas, spectrum and power-efficient speech codecs, and modulation techniques for use in the non-linear faded channels and efficient multiple access schemes. Finally, the paper concludes with a description of the current and planned NASA activities aimed at developing complex large multibeam spacecraft antennas needed for future generation mobile satellite systems.

  1. NASA's mobile satellite communications program; ground and space segment technologies

    Science.gov (United States)

    Naderi, F.; Weber, W. J.; Knouse, G. H.

    1984-01-01

    This paper describes the Mobile Satellite Communications Program of the United States National Aeronautics and Space Administration (NASA). The program's objectives are to facilitate the deployment of the first generation commercial mobile satellite by the private sector, and to technologically enable future generations by developing advanced and high risk ground and space segment technologies. These technologies are aimed at mitigating severe shortages of spectrum, orbital slot, and spacecraft EIRP which are expected to plague the high capacity mobile satellite systems of the future. After a brief introduction of the concept of mobile satellite systems and their expected evolution, this paper outlines the critical ground and space segment technologies. Next, the Mobile Satellite Experiment (MSAT-X) is described. MSAT-X is the framework through which NASA will develop advanced ground segment technologies. An approach is outlined for the development of conformal vehicle antennas, spectrum and power-efficient speech codecs, and modulation techniques for use in the non-linear faded channels and efficient multiple access schemes. Finally, the paper concludes with a description of the current and planned NASA activities aimed at developing complex large multibeam spacecraft antennas needed for future generation mobile satellite systems.

  2. President's Task Force on Communications Policy. Domestic Applications of Communication Satellite Technology. Staff Paper Four.

    Science.gov (United States)

    President's Task Force on Communications Policy, Washington, DC.

    A staff paper to the President's Task Force on Communications Policy examines the feasibility of a domestic communications satellite system. Although, with expected technological advancement, satellites may play a significant role in domestic transmission and are economically feasible right now, a number of remaining questions make the…

  3. 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.

  4. 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.

  5. Technology for a quasi-GSO satellite communications system

    OpenAIRE

    Katagi, T.; Yonezawa, R.; Chiba, I.; Urasaki, S.

    1999-01-01

    In this paper, a satellite communications system using a Quasi Geostationary Satellite Orbit (Quasi-GSO) is proposed. A 24-hour period Quasi-GSO system could give high quality communication to high latitude regions with its satellites observed from earth stations having high elevation angles. In this paper, a system concept and a deployable flat antenna with light weight antenna elements are described proposing it to be a good candidate for mobile communications satellite use.

  6. 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…

  7. 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.

  8. NASA ACTS Multibeam Antenna (MBA) System. [Advanced Communications Technology Satellite

    Science.gov (United States)

    Choung, Youn H.; Stiles, W. Herschel; Wu, Joseph; Wong, William C.; Chen, C. Harry

    1986-01-01

    The design of the Advanced Communications Technology Satellite MBA system, which provides both spot beam and scanning beam coverage to both high and low burst rates data-users is examined. The MBA consists of receive and transmit antennas installed on a common precision mounting platform that is integrated to the bus through three flexures; a lightweight system with low thermal distortion is obtained by using composite materials for the MBA structures. The RF design, which is a Cassegrain reflector with a large equivalent focal length/aperture size, is described. Consideration is given to the position of the feed in order to minimize scan loss and sidelobe levels, the size of the subreflector in order to minimize feed spillover, and antenna performance degradation caused by reflector surface distortion. Breadbroad model test result reveal that the maximum sidelobe level outside the 2.5 HPBW region is -30 dB or lower relative to the power.

  9. Satellite communication engineering

    CERN Document Server

    Kolawole, Michael Olorunfunmi

    2013-01-01

    An undeniably rich and thorough guide to satellite communication engineering, Satellite Communication Engineering, Second Edition presents the fundamentals of information communications systems in a simple and succinct way. This book considers both the engineering aspects of satellite systems as well as the practical issues in the broad field of information transmission. Implementing concepts developed on an intuitive, physical basis and utilizing a combination of applications and performance curves, this book starts off with a progressive foundation in satellite technology, and then moves on

  10. Trends In Satellite Communication

    Science.gov (United States)

    Poley, William A.; Stevens, Grady H.; Stevenson, Steven M.; Lekan, Jack; Arth, Clifford H.; Hollansworth, James E.; Miller, Edward F.

    1988-01-01

    Report assesses trends in satellite communication from present to year 2010. Examines restrictions imposed by limited spectrum resource and technology needs created by trends. Personal communications, orbiting switchboards, and videophones foreseen.

  11. The Human-Technological Interface: An Analysis of a Satellite Communication Learning Environment.

    Science.gov (United States)

    Collins, Valerie A. C.; Murphy, Peter J.

    1987-01-01

    The effectiveness of distance education methods that involve direct interaction between the student and communications satellite technology is discussed, drawing on experiences in British Columbia adult distance education programs using interactive instructional television and other modern technologies. (MSE)

  12. Mobile satellite communications technology - A summary of NASA activities

    Science.gov (United States)

    Dutzi, E. J.; Knouse, G. H.

    1986-01-01

    Studies in recent years indicate that future high-capacity mobile satellite systems are viable only if certain high-risk enabling technologies are developed. Accordingly, NASA has structured an advanced technology development program aimed at efficient utilization of orbit, spectrum, and power. Over the last two years, studies have concentrated on developing concepts and identifying cost drivers and other issues associated with the major technical areas of emphasis: vehicle antennas, speech compression, bandwidth-efficient digital modems, network architecture, mobile satellite channel characterization, and selected space segment technology. The program is now entering the next phase - breadboarding, development, and field experimentation.

  13. 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.

  14. CTS United States experiments - A progress report. [Communications Technology Satellite for high power broadcasting

    Science.gov (United States)

    Robbins, W. H.; Donoughe, P. L.

    1976-01-01

    The Communications Technology Satellite (CTS) is a high-power broadcast satellite launched by NASA on January 17, 1976. CTS is the first satellite to operate at a frequency of 12 gigahertz and incorporates technology making possible new satellite telecommunications services. CTS is a cooperative program of the United States and Canada. This paper presents the results of the United States experimental activity to date. Wide segments of the population are involved in the Experiments Program, including the scientific community, other government agencies, industry, and the education and health entities. The experiments are associated with both technological objectives and the demonstration of new community and social services via satellite.

  15. Mobile satellite communications handbook

    CERN Document Server

    Cochetti, Roger

    2014-01-01

    With a Preface by noted satellite scientist Dr. Ahmad Ghais, the Second Edition reflects the expanded user base for this technology by updating information on historic, current, and planned commercial and military satellite systems and by expanding sections that explain the technology for non-technical professionals.   The book begins with an introduction to satellite communications and goes on to provide an overview of the technologies involved in mobile satellite communications, providing basic introductions to RF Issues, power Issues, link issues and system issues. It describes

  16. The rise and fall of COMSAT technology, business, and government in satellite communications

    CERN Document Server

    Whalen, D

    2014-01-01

    Satellite communications grosses over 100 billion annually and is heading toward 200 billion. COMSAT started all of this in 1963 when it was organized in compliance with the Communications Satellite Act of 1962. COMSAT was responsible for choosing geosynchronous earth orbit (GEO), forming INTELSAT, and generally promoting the technological change that saw satellite power increase from the 40 watts of Early Bird (INTELSAT I) to the almost 10 kilowatts of INTELSAT IX; earth station antennas were reduced from 30 meters to 1 meter. The business of satellite communications was expanded to mobile co

  17. Business Use of Satellite Communications.

    Science.gov (United States)

    Edelson, Burton I.; Cooper, Robert S.

    1982-01-01

    Reviews business communications development and discusses business applications of satellite communications, system technology, and prospects for future developments in digital transmission systems. (JN)

  18. CTS /Hermes/ - United States experiments and operations summary. [Communications Technology Satellite

    Science.gov (United States)

    Donoughe, P. L.; Hunczak, H. R.

    1977-01-01

    The U.S. experiments conducted with the Communications Technology Satellite, a joint Canadian-U.S. venture launched in 1976, are discussed. The 14/12 GHz frequencies employed by the 200-W transmitter on board the satellite provide two-way television and voice communications. Applications of the satellite in the categories of health care, community services and education are considered; experiments have also made use of the special properties of the super-high frequency band (e.g. link characterization and digital communications). Time-sharing of the 14/12 GHz communication between the U.S. and Canada has functioned well.

  19. Downsizing Antenna Technologies for Mobile and Satellite Communications

    Science.gov (United States)

    Huang, J.; Densmore, A.; Tulintseff, A.; Jamnejad, V.

    1993-01-01

    Due to the increasing and stringent functional requirements (larger capacity, longer distances, etc.) of modern day communication systems, higher antenna gains are generally needed. This higher gain implies larger antenna size and mass which are undesirable to many systems. Consequently, downsizing antenna technology becomes one of the most critical areas for research and development efforts. Techniques to reduce antenna size can be categorized and are briefly discussed.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. CTS digital video college curriculum-sharing experiment. [Communications Technology Satellite

    Science.gov (United States)

    Lumb, D. R.; Sites, M. J.

    1974-01-01

    NASA-Ames Research Center, Stanford University, and Carleton University, Ottawa, Canada, are participating in a joint experiment to evaluate the feasibility and effectiveness of college curriculum sharing using compressed digital television and the Communications Technology Satellite (CTS). Each university will offer televised courses to the other during the 1976-1977 academic year via CTS, a joint program by NASA and the Canadian Department of Communications. The video compression techniques to be demonstrated will enable economical interconnection of educational institutions using existing and planned domestic satellites.

  6. Evolution of the NOAA National Weather Service Satellite Broadcast Network (SBN) to Europe's DVB-S satellite communications technology standard

    Science.gov (United States)

    Cragg, Phil; Brockman, William E.

    2006-08-01

    The National Oceanic and Atmospheric Administration's (NOAA) National Weather Service (NWS) uses a commercial Satellite Broadcast Network (SBN) to distribute weather data to the NWS AWIPS workstations and National Centers and to NWS Family of Service Users. Advances in science and technology from NOAA's observing systems, such as remote sensing satellites and NEXRAD radars, and advances in Numeric Weather Prediction have greatly increased the volume of data to be transmitted via the SBN. The NOAA-NWS SBN Evolution Program did a trade study resulting in the selection of Europe's DVB-S communication protocol as the basis for enabling a significant increase in the SBN capacity. The Digital Video Broadcast (DVB) group, started to develop digital TV for Europe through satellite broadcasting, has become the current standard for defining technology for satellite broadcasting of digital data for much of the world. NOAA-NWS implemented the DVB-S with inexpensive, Commercial Off The Shelf receiving equipment. The modernized NOAA-NWS SBN meets current performance goals and provides the basis for continued future expansion with no increase in current communication costs. This paper discusses aspects of the NOAA-NWS decision and the migration to the DVB-S standard for its commercial satellite broadcasts of observations and Numerical Weather Prediction data.

  7. 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.

  8. Characterization of the CTS 12 and 14 GHz communications links - Preliminary measurements and evaluation. [Communications Technology Satellite

    Science.gov (United States)

    Ippolito, L. J.

    1976-01-01

    The Communications Link Characterization Experiment is designed to characterize the radio frequency links of the Communications Technology Satellite. The experiment is twofold: (1) it will study the natural characteristics in the CTS frequency bands (14 GHz uplink, and 12 GHz downlink) including attenuation and signal degradation due primarily to absorption and scattering induced by precipitation, and (2) it will perform environmental measurements for the characterization of man-made, earth-based signals which could interfere with the uplink frequency bands of the satellite.

  9. Extremely high frequency (EHF) satellite communications (SATCOM) technology-transmitters and receivers

    Science.gov (United States)

    Raue, Jorg E.

    1983-10-01

    During the past three years, interest in satellite communications in the frequency bands above Ku-band has expanded dramatically. As a result, a number of key technology developments, targeted to meet specific next generation spaceborne needs, were undertaken. The state-of-the-art in solid state power transmitters and low noise receivers, including critical passive component technology, is presented. This includes filters as well as a series of rugged high performance ferrite components such as isolators, circulators and latching switches.

  10. Trends in communications satellites

    CERN Document Server

    Curtin, Denis J

    1979-01-01

    Trends in Communications Satellites offers a comprehensive look at trends and advances in satellite communications, including experimental ones such as NASA satellites and those jointly developed by France and Germany. The economic aspects of communications satellites are also examined. This book consists of 16 chapters and begins with a discussion on the fundamentals of electrical communications and their application to space communications, including spacecraft, earth stations, and orbit and wavelength utilization. The next section demonstrates how successful commercial satellite communicati

  11. Communications technology

    Science.gov (United States)

    Cuccia, C. Louis; Sivo, Joseph

    1986-01-01

    The technologies for optimized, i.e., state of the art, operation of satellite-based communications systems are surveyed. Features of spaceborne active repeater systems, low-noise signal amplifiers, power amplifiers, and high frequency switches are described. Design features and capabilities of various satellite antenna systems are discussed, including multiple beam, shaped reflector shaped beam, offset reflector multiple beam, and mm-wave and laser antenna systems. Attitude control systems used with the antenna systems are explored, along with multiplexers, filters, and power generation, conditioning and amplification systems. The operational significance and techniques for exploiting channel bandwidth, baseband and modulation technologies are described. Finally, interconnectivity among communications satellites by means of RF and laser links is examined, as are the roles to be played by the Space Station and future large space antenna systems.

  12. 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.

  13. Communications satellites - The experimental years

    Science.gov (United States)

    Edelson, B. I.

    1983-10-01

    Only eight years after the launc of Sputnik-1 by the Soviet Union, the first commercial satellite, 'Early Bird', entered service. In just twelve years commercial satellite service extended around the earth and became profitable. The reasons for the successful development of the communications satellite services in a comparatively short time are considered. These reasons are related to the presence of three ingredients, taking into account technology to create the system, communications requirements to form a market, and a management structure to implement the system. The formation of the concept of using earth orbiting satellites for telecommunications is discussed. It is pointed out that the years from 1958 to 1964 were the true 'experimental years' for satellite communications. The rapid development of technology during this crucial period is described, giving attention to passive satellites, active systems, and development satellites.

  14. Educational Applications of Communications Satellites in Canada. New Technologies in Canadian Education Series. Paper 12.

    Science.gov (United States)

    Richmond, J. Murray

    Canada has explored the use of satellites as a means to provide information and communications services to geographically isolated populations since 1962. Between 1972 and 1984, five series of satellites known as Anik A, B, C, and D and Hermes were launched. Each satellite provided expanded communications services, and each led to research and…

  15. Renewable Energy SCADA/Training Using NASA's Advanced Technology Communication Satellite

    Science.gov (United States)

    Kalu, A.; Emrich, C.; Ventre, G.; Wilson, W.; Acosta, Roberto (Technical Monitor)

    2000-01-01

    The lack of electrical energy in the rural communities of developing countries is well known, as is the economic unfeasibility of providing much needed energy to these regions via electric grids. Renewable energy (RE) can provide an economic advantage over conventional forms in meeting some of these energy needs. The use of a Supervisory Control and Data Acquisition (SCADA) arrangement via satellite could enable experts at remote locations to provide technical assistance to local trainees while they acquire a measure of proficiency with a newly installed RE system through hands-on training programs using the same communications link. Upon full mastery of the technologies, indigenous personnel could also employ similar SCADA arrangements to remotely monitor and control their constellation of RE systems. Two separate ACTS technology verification experiments (TVEs) have demonstrated that the portability of the Ultra Small Aperture Terminal (USAT) and the versatility of NASA's Advanced Communications Technology Satellite (ACTS), as well as the advantages of Ka band satellites, can be invaluable in providing energy training via distance education (DE), and for implementing renewable energy system SCADA. What has not been tested is the capabilities of these technologies for a simultaneous implementation of renewable energy DE and SCADA. Such concurrent implementations will be useful for preparing trainees in developing countries for their eventual SCADA operations. The project described in this correspondence is the first effort, to our knowledge, in this specific TVE. The setup for this experiment consists of a one-Watt USAT located at Florida Solar Energy Center (FSEC) connected to two satellite modems tuned to different frequencies to establish two duplex ACTS Ka-band communication channels. A short training program on operation and maintenance of the system will be delivered while simultaneously monitoring and controlling the hybrid using the same satellite

  16. Renewable Energy SCADA/Training Using NASA's Advanced Technology Communication Satellite

    Science.gov (United States)

    Kalu, A.; Emrich, C.; Ventre, G.; Wilson, W.; Acosta, Roberto (Technical Monitor)

    2000-01-01

    The lack of electrical energy in the rural communities of developing countries is well known, as is the economic unfeasibility of providing much needed energy to these regions via electric grids. Renewable energy (RE) can provide an economic advantage over conventional forms in meeting some of these energy needs. The use of a Supervisory Control and Data Acquisition (SCADA) arrangement via satellite could enable experts at remote locations to provide technical assistance to local trainees while they acquire a measure of proficiency with a newly installed RE system through hands-on training programs using the same communications link. Upon full mastery of the technologies, indigenous personnel could also employ similar SCADA arrangements to remotely monitor and control their constellation of RE systems. Two separate ACTS technology verification experiments (TVEs) have demonstrated that the portability of the Ultra Small Aperture Terminal (USAT) and the versatility of NASA's Advanced Communications Technology Satellite (ACTS), as well as the advantages of Ka band satellites, can be invaluable in providing energy training via distance education (DE), and for implementing renewable energy system SCADA. What has not been tested is the capabilities of these technologies for a simultaneous implementation of renewable energy DE and SCADA. Such concurrent implementations will be useful for preparing trainees in developing countries for their eventual SCADA operations. The project described in this correspondence is the first effort, to our knowledge, in this specific TVE. The setup for this experiment consists of a one-Watt USAT located at Florida Solar Energy Center (FSEC) connected to two satellite modems tuned to different frequencies to establish two duplex ACTS Ka-band communication channels. A short training program on operation and maintenance of the system will be delivered while simultaneously monitoring and controlling the hybrid using the same satellite

  17. Satellite communications principles and applications

    CERN Document Server

    Calcutt, David

    1994-01-01

    Satellites are increasingly used for global communications, as well as for radio and television transmissions. With the growth of mobile communications, and of digital technology, the use of satellite systems is set to expand substantially and already all students of electronics or communications engineering must study the subject.This book steers a middle path between offering a basic understanding of the process of communication by satellite and the methodology used; and the extensive mathematical analysis normally adopted in similar texts. It presents the basic concepts, using as mu

  18. Newnes communications technology handbook

    CERN Document Server

    Lewis, Geoff

    1994-01-01

    Newnes Communications Technology Handbook provides a discussion on different topics relevant to communications technology. The book is comprised of 39 chapters that tackle a wide variety of concern in communications technology. The coverage of the text includes technologies, such as analog digital communications systems, radio frequency receiver, and satellite systems. The book also discusses some methods and techniques used in communications technology, including mixer signal processing, modulation and demodulation, and spread spectrum techniques. The text will be of great use to engineers, t

  19. ACTS (Advanced Communications Technology Satellite) Propagation Experiment: Preprocessing Software User's Manual

    Science.gov (United States)

    Crane, Robert K.; Wang, Xuhe; Westenhaver, David

    1996-01-01

    The preprocessing software manual describes the Actspp program originally developed to observe and diagnose Advanced Communications Technology Satellite (ACTS) propagation terminal/receiver problems. However, it has been quite useful for automating the preprocessing functions needed to convert the terminal output to useful attenuation estimates. Prior to having data acceptable for archival functions, the individual receiver system must be calibrated and the power level shifts caused by ranging tone modulation must be received. Actspp provides three output files: the daylog, the diurnal coefficient file, and the file that contains calibration information.

  20. Design, construction and testing of the Communications Technology Satellite protection against spacecraft charging

    Science.gov (United States)

    Gore, J. V.

    1977-01-01

    Detailed discussions are presented of the measures taken on the Communications Technology Satellite (CTS or Hermes) which provide protection against the effects of spacecraft charging. These measures include: a comprehensive grounding philosophy and implementation; provision of command and data line transmitters and receivers for transient noise immunity; and a fairly restrictive EMI specification. Ground tests were made on materials and the impact of these tests on the CTS spacecraft is described. Hermes, launched on 17 January 1976 on a 2914 Delta vehicle, has successfully completed 10 months of operations. Anomalies observed are being assessed in relation to spacecraft charging, but no definite correlations have yet been established. A list of conclusions with regard to the CTS experience is given and recommendations for future spacecraft are also listed.

  1. 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.

  2. Advanced Communications Technology Satellite (ACTS) Fade Compensation Protocol Impact on Very Small-Aperture Terminal Bit Error Rate Performance

    Science.gov (United States)

    Cox, Christina B.; Coney, Thom A.

    1999-01-01

    The Advanced Communications Technology Satellite (ACTS) communications system operates at Ka band. ACTS uses an adaptive rain fade compensation protocol to reduce the impact of signal attenuation resulting from propagation effects. The purpose of this paper is to present the results of an analysis characterizing the improvement in VSAT performance provided by this protocol. The metric for performance is VSAT bit error rate (BER) availability. The acceptable availability defined by communication system design specifications is 99.5% for a BER of 5E-7 or better. VSAT BER availabilities with and without rain fade compensation are presented. A comparison shows the improvement in BER availability realized with rain fade compensation. Results are presented for an eight-month period and for 24 months spread over a three-year period. The two time periods represent two different configurations of the fade compensation protocol. Index Terms-Adaptive coding, attenuation, propagation, rain, satellite communication, satellites.

  3. 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)

  4. Life characteristics assessment of the communications technology satellite transmitter experiment package

    Science.gov (United States)

    Smetana, J.; Curren, A. N.

    1979-01-01

    The performance characteristics of the transmitter experiment package (TEP) aboard the Communications Technology Satellite (CTS) measured during its first 2 years in orbit are presented. The TEP consists of a nominal 200 watt output stage tube (OST), a supporting power processing system (PPS), and a variable conductance heat pipe system (VCHPS). The OST, a traveling wave tube augmented with a 10 stage depressed collector has an overall saturated average efficiency of 51.5 percent and an average saturated radio frequency (rf) output power at center band frequency of 240 watts. The PPS operated with a measured efficiency of 86.5 to 88.5 percent. The VCHPS, using three pipes to conduct heat from the PPS and the OST to a 52 by 124 centimeter radiator fin, maintained the PPS baseplate temperature below 50 C for all operating conditions. The TEP performance characteristics presented include frequency response, rf output power, thermal performance, and efficiency. Communications characteristics were evaluated by using both video and audio modulated signals. On four occasions, the TEP experienced temporary thermal control system malfunctions. The anomalies were terminated safely, and the problem was investigated because of the potential for TEP damage due to the signficant temperature increases. Safe TEP operating procedures were established.

  5. Dynamic rain fade compensation techniques for the advanced communications technology satellite

    Science.gov (United States)

    Manning, Robert M.

    1992-01-01

    The dynamic and composite nature of propagation impairments that are incurred on earth-space communications links at frequencies in and above the 30/20 GHz Ka band necessitate the use of dynamic statistical identification and prediction processing of the fading signal in order to optimally estimate and predict the levels of each of the deleterious attenuation components. Such requirements are being met in NASA's Advanced Communications Technology Satellite (ACTS) project by the implementation of optimal processing schemes derived through the use of the ACTS Rain Attenuation Prediction Model and nonlinear Markov filtering theory. The ACTS Rain Attenuation Prediction Model discerns climatological variations on the order of 0.5 deg in latitude and longitude in the continental U.S. The time-dependent portion of the model gives precise availability predictions for the 'spot beam' links of ACTS. However, the structure of the dynamic portion of the model, which yields performance parameters such as fade duration probabilities, is isomorphic to the state-variable approach of stochastic control theory and is amenable to the design of such statistical fade processing schemes which can be made specific to the particular climatological location at which they are employed.

  6. Satellite Communications for ATM

    Science.gov (United States)

    Shamma, Mohammed A.

    2003-01-01

    This presentation is an overview on Satellite Communication for the Aeronautical Telecommunication Management (ATM) research. Satellite Communications are being considered by the FAA and NASA as a possible alternative to the present and future ground systems supporting Air Traffic Communications. The international Civil Aviation Organization (ICAO) have in place Standards and Recommended Practices (SARPS) for the Aeronautical Mobile Satellite Services (AMSS) which is mainly derived from the pre-existing Inmarsat service that has been in service since the 1980s. The Working Group A of the Aeronautical Mobile Communication Panel of ICAO has also been investigating SARPS for what is called the Next Generation Satellite Service (NGSS) which conforms less to the Inmarsat based architecture and explores wider options in terms of satellite architectures. Several designs are being proposed by Firms such as Boeing, ESA, NASA that are geared toward full or secondary usage of satellite communications for ATM. Satellite communications for ATM can serve several purposes ranging from primary usage where ground services would play a minimal backup role, to an integrated solution where it will be used to cover services, or areas that are less likely to be supported by the proposed and existing ground infrastructure. Such Integrated roles can include usage of satellite communications for oceanic and remote land areas for example. It also can include relieving the capacity of the ground network by providing broadcast based services of Traffic Information Services messages (TIS-B), or Flight Information Services (FIS-B) which can take a significant portion of the ground system capacity. Additionally, satellite communication can play a backup role to support any needs for ground replacement, or additional needed capacity even after the new digital systems are in place. The additional bandwidth that can be provided via satellite communications can also open the door for many new

  7. Communication satellite system beyond the year 2000

    Science.gov (United States)

    Robertson, G. J.; Fourquet, J. M.

    1991-10-01

    The primary evolutionary factors of satellite communications technologies are reviewed based on the results of a study of novel satellite developments. A critical evaluation of the viability and availability of the technologies is utilized in conjunction with market forecasts to determine promising commercial strategies. Modern technologies are almost prepared for the development of a class of communications satellites and include bandwidth utilization, spacecraft bus modularity, and functional integration.

  8. 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

  9. 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.

  10. An Overview Of Operational Satellites Built By China: Communications Satellites (Part1)

    Institute of Scientific and Technical Information of China (English)

    Guang Bo

    2008-01-01

    @@ Communications satellite technology has seen great advances since Decemher 1958 when the Americans launched the first experimental communications satellite.Currently, satellite communications account for over 80 percent of the intercontinental communications traffic and 100 percent of international live TV broadcast, while taking part in domestic and regional services. Moreover, the satellite communication service is showing a favorable continuous growth tendency.

  11. Communication Satellite Technology as a Potential Comprehensive Delivery System for Correctional Institution Education and Training Programs

    Science.gov (United States)

    Polcyn, Kenneth A.

    1977-01-01

    By pooling resources and using communication satellites to access quality regional or national programs and personnel, institutions may be able to determine inmate aptitudes and career options, receive career counselling for inmates based on job trends, access educational and vocational training programs that match the inmates' capabilities and…

  12. Communication Satellite Technology as a Potential Comprehensive Delivery System for Correctional Institution Education and Training Programs

    Science.gov (United States)

    Polcyn, Kenneth A.

    1977-01-01

    By pooling resources and using communication satellites to access quality regional or national programs and personnel, institutions may be able to determine inmate aptitudes and career options, receive career counselling for inmates based on job trends, access educational and vocational training programs that match the inmates' capabilities and…

  13. Future communications satellite applications

    Science.gov (United States)

    Bagwell, James W.

    1992-01-01

    The point of view of the research is made through the use of viewgraphs. It is suggested that future communications satellite applications will be made through switched point to point narrowband communications. Some characteristics of which are as follows: small/low cost terminals; single hop communications; voice compatible; full mesh networking; ISDN compatible; and possible limited use of full motion video. Some target applications are as follows: voice/data networks between plants and offices in a corporation; data base networking for commercial and science users; and cellular radio internodal voice/data networking.

  14. Proceedings of the Seventeenth NASA Propagation Experimenters Meeting (NAPEX 17) and the Advanced Communications Technology Satellite (ACTS) Propagation Studies Miniworkshop

    Science.gov (United States)

    Davarian, Faramaz (Editor)

    1993-01-01

    The NASA Propagation Experimenters Meeting (NAPEX) is convened annually to discuss studies made on radio wave propagation by investors from domestic and international organizations. NAPEX 17 was held on 15 June 1993. The meeting was organized into two technical sessions. The first session was dedicated to slant path propagation studies and experiments. The second session focused on propagation studies for mobile and personal communications. Preceding NAPEX 17, the Advanced Communications Technology Satellite (ACTS) Propagation Studies Miniworkshop was held on 14 June 1993 to review ACTS propagation activities with emphasis on ACTS experiments status and data collection, processing, and exchange.

  15. Advanced Communications Technology Satellite (ACTS). Phase 1: Industrial/academic experimenters

    Science.gov (United States)

    Maisel, James E.; Nowlin, Robert W.

    1992-01-01

    This report presents the work done at Arizona State University under the ACTS Experimenters Program. The main thrust of the Program was to develop experiments to test, evaluate, and prove the commercial worthiness of the ACTS satellite which is scheduled for launch in 1993. To accomplish this goal, meetings were held with various governmental, industrial, and academic units to discuss the ACTS satellite and its technology and possible experiments that would generate industrial interest and support for ASU's efforts. Several local industries generated several experiments of their own. The investigators submitted several experiments of educational, medical, commercial, and technical value and interest. The disposition of these experimental proposals is discussed in this report.

  16. Space industrialization - Education. [via communication satellites

    Science.gov (United States)

    Joels, K. M.

    1978-01-01

    The components of an educational system based on, and perhaps enhanced by, space industrialization communications technology are considered. Satellite technology has introduced a synoptic distribution system for various transmittable educational media. The cost of communications satellite distribution for educational programming has been high. It has, therefore, been proposed to utilize Space Shuttle related technology and Large Space Structures (LSS) to construct a system with a quantum advancement in communication capability and a quantum reduction in user cost. LSS for communications purposes have three basic advantages for both developed and emerging nations, including the ability to distribute signals over wide geographic areas, the reduced cost of satellite communications systems versus installation of land based systems, and the ability of a communication satellite system to create instant educational networks.

  17. Experimental Satellite Quantum Communications.

    Science.gov (United States)

    Vallone, Giuseppe; Bacco, Davide; Dequal, Daniele; Gaiarin, Simone; Luceri, Vincenza; Bianco, Giuseppe; Villoresi, Paolo

    2015-07-24

    Quantum communication (QC), namely, the faithful transmission of generic quantum states, is a key ingredient of quantum information science. Here we demonstrate QC with polarization encoding from space to ground by exploiting satellite corner cube retroreflectors as quantum transmitters in orbit and the Matera Laser Ranging Observatory of the Italian Space Agency in Matera, Italy, as a quantum receiver. The quantum bit error ratio (QBER) has been kept steadily low to a level suitable for several quantum information protocols, as the violation of Bell inequalities or quantum key distribution (QKD). Indeed, by taking data from different satellites, we demonstrate an average value of QBER=4.6% for a total link duration of 85 s. The mean photon number per pulse μ_{sat} leaving the satellites was estimated to be of the order of one. In addition, we propose a fully operational satellite QKD system by exploiting our communication scheme with orbiting retroreflectors equipped with a modulator, a very compact payload. Our scheme paves the way toward the implementation of a QC worldwide network leveraging existing receivers.

  18. Trends in NASA communication satellites.

    Science.gov (United States)

    Sivo, J. N.; Robbins, W. H.; Stretchberry, D. M.

    1972-01-01

    Discussion of the potential applications of satellite communications technology in meeting the national needs in education, health care, culture, and data transfer techniques. Experiments with the NASA ATS 1, 3 and 5 spacecraft, which are conducted in an attempt to satisfy such needs, are reviewed. The future needs are also considered, covering the requirements of multiple region coverage, communications between regions, large numbers of ground terminals, multichannel capability and high quality TV pictures. The ATS F and CTS spacecraft are expected to be available in the near future to expand experiments in this field.

  19. Living antennas on communication satellites

    DEFF Research Database (Denmark)

    Lumholt, Michael

    2003-01-01

    Crises change the global pattern of communication. The communications problems occur because the satellites are optimized to cover specific geographic areas, and these areas cannot be altered once the satellites are in Earth orbit. An effective solution to the problem is to equip communication...... satellites with "living" antennas that can adjust their radiation coverage areas according to the new demands. The development of living antennas is, therefore, among the focus areas identified and supported by the European Space Agency, ESA....

  20. Narrow-Band Applications of Communications Satellites.

    Science.gov (United States)

    Cowlan, Bert; Horowitz, Andrew

    This paper attempts to describe the advantages of "narrow-band" applications of communications satellites for education. It begins by discussing the general controversy surrounding the use of satellites in education, by placing the concern within the larger context of the general debate over the uses of new technologies in education, and by…

  1. 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…

  2. Plan of advanced satellite communication experiments using ETS-6

    Science.gov (United States)

    Ikegami, Tetsushi

    1989-01-01

    In 1992, an Engineering Test Satellite 6 is scheduled to be launched by an H-2 rocket. The missions of ETS-6 are to establish basic technologies of inter-satellite communications using S-band, millimeter waves and optical beams and of fixed and mobile satellite communications using multibeam antenna on board the satellite. A plan of the experiments is introduced.

  3. Advanced satellite communication system

    Science.gov (United States)

    Staples, Edward J.; Lie, Sen

    1992-01-01

    The objective of this research program was to develop an innovative advanced satellite receiver/demodulator utilizing surface acoustic wave (SAW) chirp transform processor and coherent BPSK demodulation. The algorithm of this SAW chirp Fourier transformer is of the Convolve - Multiply - Convolve (CMC) type, utilizing off-the-shelf reflective array compressor (RAC) chirp filters. This satellite receiver, if fully developed, was intended to be used as an on-board multichannel communications repeater. The Advanced Communications Receiver consists of four units: (1) CMC processor, (2) single sideband modulator, (3) demodulator, and (4) chirp waveform generator and individual channel processors. The input signal is composed of multiple user transmission frequencies operating independently from remotely located ground terminals. This signal is Fourier transformed by the CMC Processor into a unique time slot for each user frequency. The CMC processor is driven by a waveform generator through a single sideband (SSB) modulator. The output of the coherent demodulator is composed of positive and negative pulses, which are the envelopes of the chirp transform processor output. These pulses correspond to the data symbols. Following the demodulator, a logic circuit reconstructs the pulses into data, which are subsequently differentially decoded to form the transmitted data. The coherent demodulation and detection of BPSK signals derived from a CMC chirp transform processor were experimentally demonstrated and bit error rate (BER) testing was performed. To assess the feasibility of such advanced receiver, the results were compared with the theoretical analysis and plotted for an average BER as a function of signal-to-noise ratio. Another goal of this SBIR program was the development of a commercial product. The commercial product developed was an arbitrary waveform generator. The successful sales have begun with the delivery of the first arbitrary waveform generator.

  4. A generalized transmultiplexer and its application to mobile satellite communications

    Science.gov (United States)

    Ichiyoshi, Osamu

    A generalization of digital transmultiplexer technology is presented. The proposed method can realize transmultiplexer (TMUX) and transdemultiplexer (TDUX) filter banks whose element filters have bandwidths greater than the channel spacing frequency. This feature is useful in many communications applications. As an example, a satellite switched (SS) Frequency Division Multiple Access (FDMA) system is proposed for spot beam satellite communications, particularly for mobile satellite communications.

  5. Cultural Effects and Uses of Communication Satellites.

    Science.gov (United States)

    Schramm, Wilbur

    The communication satellite already has developed a mature technology. It carries a substantial part of the world's long range communication, and is now useable for special cultural and educational purposes. Major cultural effects come from its contribution to increasing enormously the flow of information in the world. It will increase human…

  6. Delivery of Instructional Materials Using a Communications Satellite.

    Science.gov (United States)

    Bransford, Louis A.; Diebler, Mary

    During the past decade, satellite technology has grown increasingly more sophisticated. Satellites are being used in public interest activities, especially through the Public Service Satellite Consortium. But what about the field of education? How can education, especially vocational education, make use of satellite communications technology? In…

  7. On-orbit control of the Communications Technology Satellite (CTS)/HERMES

    Science.gov (United States)

    Raine, H. R.

    1980-01-01

    A variety of control functions for the CIS HERMES satellite are reviewed. Its mission, to demonstrate high power SHF (12 GHz) transmission is discussed. The satellite was controlled in geostationary orbit for nearly four years from the satellite control center in Ottawa, Canada. Highlights of these operations are outlined. The interactions between many of the automatic onboard control functions and control from the ground are described. Special emphasis is placed on the characteristics and performance of the three axis attitude control system.

  8. Trends in mobile satellite communication

    Science.gov (United States)

    Johannsen, Klaus G.; Bowles, Mike W.; Milliken, Samuel; Cherrette, Alan R.; Busche, Gregory C.

    1993-01-01

    Ever since the U.S. Federal Communication Commission opened the discussion on spectrum usage for personal handheld communication, the community of satellite manufacturers has been searching for an economically viable and technically feasible satellite mobile communication system. Hughes Aircraft Company and others have joined in providing proposals for such systems, ranging from low to medium to geosynchronous orbits. These proposals make it clear that the trend in mobile satellite communication is toward more sophisticated satellites with a large number of spot beams and onboard processing, providing worldwide interconnectivity. Recent Hughes studies indicate that from a cost standpoint the geosynchronous satellite (GEOS) is most economical, followed by the medium earth orbit satellite (MEOS) and then by the low earth orbit satellite (LEOS). From a system performance standpoint, this evaluation may be in reverse order, depending on how the public will react to speech delay and collision. This paper discusses the trends and various mobile satellite constellations in satellite communication under investigation. It considers the effect of orbital altitude and modulation/multiple access on the link and spacecraft design.

  9. 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

  10. Space Power for Communication Satellites Beyond 1995

    Science.gov (United States)

    Pierce, P. R.

    1984-01-01

    The space power trends for communication satellites beginning in the mid-70's are reviewed. Predictions of technology advancements and requirements were compared with actual growth patterns. The conclusions derived suggest that the spacecraft power system technology base and present rate of advancement will not be able to meet the power demands of the early to mid-90's. It is recommended that an emphasis on accelerating the technology development be made to minimize the technology gap.

  11. Application of the advanced communications technology satellite to teleradiology and real-time compressed ultrasound video telemedicine.

    Science.gov (United States)

    Stewart, B K; Carter, S J; Cook, J N; Abbe, B S; Pinck, D; Rowberg, A H

    1999-05-01

    The authors have investigated the application of the NASA Advanced Communications Technology Satellite (ACTS) to teleradiology and telemedicine using the Jet Propulsion Laboratory (JPL)-developed ACTS Mobile Terminal (AMT) uplink. In this experiment, bidirectional 128, 256, and 384 kbps satellite links were established between the ACTS/AMT, the ACTS in geosynchronous orbit, and the downlink terrestrial terminal at JPL. A terrestrial Integrated Digital Services Network (ISDN) link was established from JPL to the University of Washington Department of Radiology to complete the bidirectional connection. Ultrasound video imagery was compressed in real-time using video codecs adhering to the International Telecommunication Union-Telecommunication Standardization Sector (ITU-T) Recommendation H.261. A 16 kbps in-band audio channel was used throughout. A five-point Likert scale was used to evaluate the quality of the compressed ultrasound imagery at the three transmission bandwidths (128, 256, and 384 kbps). The central question involved determination of the bandwidth requirements to provide sufficient spatial and contrast resolution for the remote visualization of fine- and low-contrast objects. The 384 kbps bandwidth resulted in only slight tiling artifact and fuzziness owing to the quantizer step size; however, these motion artifacts were rapidly resolved in time at this bandwidth. These experiments have demonstrated that real-time compressed ultrasound video imagery can be transmitted over multiple ISDN line bandwidth links with sufficient temporal, contrast, and spatial resolution for clinical diagnosis of multiple disease and pathology states to provide subspecialty consultation and educational at a distance.

  12. Accelerated life tests of specimen heat pipe from Communication Technology Satellite (CTS) project

    Science.gov (United States)

    Tower, L. K.; Kaufman, W. B.

    1977-01-01

    A gas-loaded variable conductance heat pipe of stainless steel with methanol working fluid identical to one now on the CTS satellite was life tested in the laboratory at accelerated conditions for 14 200 hours, equivalent to about 70 000 hours at flight conditions. The noncondensible gas inventory increased about 20 percent over the original charge. The observed gas increase is estimated to increase operating temperature by about 2.2 C, insufficient to harm the electronic gear cooled by the heat pipes in the satellite. Tests of maximum heat input against evaporator elevation agree well with the manufacturer's predictions.

  13. China Satcom: Innovating Satellite Communication

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    China Satellite Communications Group Corporation (China Satcom) is a state-owned large-sized key enterprise formally established on Dec. 19, 2001 according to the general deployment of the State Council on telecommunication system reform. Relying on its complete service system, China Satcom provides various users with specialized and high quality information communication service.

  14. Mobile satellite communications for consumers

    Science.gov (United States)

    Noreen, Gary K.

    1991-11-01

    The RadioSat system based on MSAT satellites and scheduled for launch in 1994 is described. The RadioSat system will provide integrated communications and navigation services to consumers, including nationwide digital audio broadcasts, data broadcasts, precision navigation, and two-way voice and data communications. Particular attention is given to the MSAT satellite system capabilities and economics. It is concluded that the RadioSat system will be capable of providing a low-cost, highly flexible two-way communications for consumers that can be adapted to various applications.

  15. Man-Made Moons: Satellite Communications for Schools.

    Science.gov (United States)

    Grayson, Lawrence P.; And Others

    In an effort to prepare teachers for the coming changes in education caused by the rapidly developing communication satellite technology, this monograph offers a non-technical background to this new development. It begins by explaining the importance of such satellites and offers a layman's guide to the technology of satellite systems. It reviews…

  16. Information and communication technology

    Science.gov (United States)

    Edelson, Burton I.; Pelton, Joseph N.; Bostian, Charles W.; Brandon, William T.; Chan, Vincent W. S.; Hager, E. Paul; Helm, Neil R.; Jennings, Raymond D.; Kwan, Robert K.; Mahle, Christoph E.

    1994-01-01

    NASA and the National Science Foundation (NSF) commissioned a panel of U.S. experts to study the international status of satellite communications systems and technology. The study covers emerging systems concepts, applications, services, and the attendant technologies. The panel members traveled to Europe, Japan, and Russia to gather information firsthand. They visited 17 sites in Europe, 20 in Japan, and 4 in Russia. These included major manufacturers, government organizations, service providers, and associated research and development facilities. The panel's report was reviewed by the sites visited, by the panel, and by representatives of U.S. industry. The report details the information collected and compares it to U.S. activities.

  17. 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.

  18. Advances in satellite communications

    CERN Document Server

    Minoli, Daniel

    2015-01-01

    Discussing advances in modulation techniques and HTS spotbeam technologiesSurveying emerging high speed aeronautical mobility services and maritime and other terrestrial mobility servicesAssessing M2M (machine-to-machine) applications, emerging Ultra HD video technologies and new space technology

  19. Laser Communication Experiments with Artemis Satellite

    Science.gov (United States)

    Kuzkov, Sergii; Sodnik, Zoran; Kuzkov, Volodymyr

    2013-10-01

    In November 2001, the European Space Agency (ESA) established the world-first inter-satellite laser communication link between the geostationary ARTEMIS satellite and the low Earth orbiting (LEO) SPOT-4 Earth observation satellite, demonstrating data rates of 50 Mbps. In 2006, the Japanese Space Agency launched the KIRARI (OICETS) LEO satellite with a compatible laser communication terminal and bidirectional laser communication links (50 Mbps and 2 Mbps) were successfully realized between KIRARI and ARTEMIS. ESA is now developing the European Data Relay Satellite (EDRS) system, which will use laser communication technology to transmit data between the Sentinel 1 and 2 satellites in LEO to two geostationary satellites (EDRS-A and EDRS-C) at data rates of 1.8 Gbps. As the data handling capabilities of state-of-the-art telecommunication satellites in GEO increase so is the demand for the feeder-link bandwidth to be transmitted from ground. This is why there is an increasing interest in developing high bandwidth ground-to-space laser communication systems working through atmosphere. In 2002, the Main Astronomical Observatory (MAO) started the development of its own laser communication system for its 0.7m AZT-2 telescope, located in Kyiv, Ukraine. The work was supported by the National Space Agency of Ukraine and by ESA. MAO developed a highly accurate computerized tracking system for AZT-2 telescope and a compact laser communication package called LACES (Laser Atmosphere and Communication Experiments with Satellites). The LACES instrument includes a camera of the pointing and tracking subsystems, a receiver module, a laser transmitter module, a tip/tilt atmospheric turbulence compensation subsystem, a bit error rate tester module and other optical and electronic components. The principal subsystems are mounted on a platform, which is located at the Cassegrain focus of the AZT-2 telescope. All systems were tested with the laser communication payload on-board ARTEMIS and

  20. Space communication link propagation data for selected cities within the multiple beam and steerable antenna coverage areas of the advanced communications technology satellite

    Science.gov (United States)

    Manning, Robert M.

    1988-01-01

    Rain attenuation propagation data for 68 cities within the coverage area of the multiple beam and steerable antennas of the Advanced Communications Technology Satellite (ACTS) are presented. These data provide the necessary data base for purposes of communication link power budgeting and rain attenuation mitigation controller design. These propagation parameters are derived by applying the ACTS Rain Attenuation Prediction Model to these 68 locations. The propagation parameters enumerated in tabular form for each location are as follows: (1) physical description of the link and location (e.g., latitude, longitude, antenna elevation angle, etc.), link availability versus attenuation margin (also in graphical form), fading time across fade depths of 3, 5, 8, and 15 dB versus fade duration, and required fade control response time for controller availabilities of 99.999, 99.99, 99.9, and 99 percent versus sub-threshold attenuation levels. The data for these specific locations can be taken to be representative of regions near these locations.

  1. Low Earth orbit communications satellite

    Science.gov (United States)

    Moroney, D.; Lashbrook, D.; Mckibben, B.; Gardener, N.; Rivers, T.; Nottingham, G.; Golden, B.; Barfield, B.; Bruening, J.; Wood, D.

    1992-01-01

    A current thrust in satellite communication systems considers a low-Earth orbiting constellations of satellites for continuous global coverage. Conceptual design studies have been done at the time of this design project by LORAL Aerospace Corporation under the program name GLOBALSTAR and by Motorola under their IRIDIUM program. This design project concentrates on the spacecraft design of the GLOBALSTAR low-Earth orbiting communication system. Overview information on the program was gained through the Federal Communications Commission licensing request. The GLOBALSTAR system consists of 48 operational satellites positioned in a Walker Delta pattern providing global coverage and redundancy. The operational orbit is 1389 km (750 nmi) altitude with eight planes of six satellites each. The orbital planes are spaced 45 deg., and the spacecraft are separated by 60 deg. within the plane. A Delta 2 launch vehicle is used to carry six spacecraft for orbit establishment. Once in orbit, the spacecraft will utilize code-division multiple access (spread spectrum modulation) for digital relay, voice, and radio determination satellite services (RDSS) yielding position determination with accuracy up to 200 meters.

  2. A research feasibility study proposal for conducting experimental research in curriculum sharing via Communications Technology Satellite among institutions having large minority enrollments

    Science.gov (United States)

    Williams, L., Jr.

    1978-01-01

    The applicability of the tele-conference method of curriculum sharing as well as the sharing of scientific research results between universities and industrial organizations was evaluated in relation to other techniques and methods. Ten universities cooperated with NC A&T State University in an effort to increase the number of minority scientists and engineers in the USA via the utilization of the communication features of satellites. Research activities, experiments and studies in curriculum sharing are described as well as the techniques, interconnections and equipment utilized. Suggested methods and recommendations for a continuation of innovative applications of satellite technology in higher education at NC A&T State University are included.

  3. Communication Satellites, 1958-1992

    Science.gov (United States)

    1991-12-31

    Indonesian Domestic Sate)- 0.00 i te Commu nicat ions System," Paper 78-613, AIAA 7th Comn- -1.00 -6. C. C. Sanderson and B. R. Elbert. -Communication System...Computer Networking via Satellite." Conisat 7thclnical Re- Sanderson . T. R., et al.. "World-Wide Interactive Access to Scien- view. Vol. 10. No. I...Militar" Communications Comltir- Brandon . W. T., "Opportunities for Small, Low-Cost. SHF Satel- ence: Milhon 82 (October 1982). lite Communications

  4. Review on Development and New Technologies of Military Satellite Communications Aboard%国外军事卫星通信发展及新技术综述

    Institute of Scientific and Technical Information of China (English)

    朱立东

    2016-01-01

    The military communication is one of the most important factors to determine the outcome of war.The side having infor⁃mation superiority is more active in the war.The military communication includes HF communication,VHF communication,meteor trail communication and satellite communication.The satellite communication has such advantages as wide coverage and large capacity,which can meet the requirements of information transmission in the battlefield in a better way. The military powers represented by the United States of America,Russia and West Europe possess advanced technologies of military satellite communication,have built some typical military satellite communication systems,and have applied them to information transmission in the battlefield,which help the operational commanding authority to make real⁃time decision in military countermeasures.To get the advantages of military countermeasures,these military powers continue developing new techniques,and remain in a dominant position in information countermeasures.On the basis of analyzing the development trend of military satellite communication,this paper introduces briefly some new technologies.%军事通信是决定战争胜负的重要因素,具有信息优势的一方更容易获得战争的主动权。军事通信包含短波通信、超短波通信、流星余迹通信、卫星通信等方式,其中卫星通信具有覆盖范围广、容量大等优点,能更好地满足战场信息传输需求。以美国、俄罗斯、西欧发达国家为代表的军事强国,拥有先进的军事卫星通信技术,建造了一些典型的军事卫星通信系统,并应用于战场信息传递,为指挥机关的实时决策提供依据。为了在军事对抗中保持优势,这些军事强国又不断发展新技术,在信息对抗中始终处于主导地位。在分析现有军事卫星通信发展动态的基础上,对适用于军事卫星通信的新技术进行了综述。

  5. Beyond ATS-6: Social Uses of Communications Satellites.

    Science.gov (United States)

    Cater, Douglass

    A panel discussion was held to examine the efficacy of the Applications Technology Satellites, powerful communication satellites designed to send quality signals to low-cost ground terminals. The satellites have been used on an experimental basis in rural America, Canada, and India. While the panel generally agreed on the great potential of the…

  6. Communication Satellites 1958 to 1986

    Science.gov (United States)

    1984-10-01

    effort that is still advancing the state of the art . 2-1 3. EXPERIMENTAL SATELLITES Although the performance of communication satellites could be...bandwidths was much beyond the state of the art . The choice of the Delta launch vehicle provided basic design constraints such as size, weight, and... Griego M6/215 A. S. Gilcrest M4/958 T. J. Carr M5/699 C. H. Bredall M5/690 J. B. Bryson M5/669 R. L. Porter M5/692 T. M. Bedbury M5/669 R. D. Smith

  7. Vocoders in mobile satellite communications

    Science.gov (United States)

    Kriedte, W.; Canavesio, F.; dal Degan, N.; Pirani, G.; Rusina, F.; Usai, P.

    Owing to the power constraints that characterize onboard transmission sections, low-bit-rate coders seem suitable for speech communications inside mobile satellite systems. Vocoders that operate at rates below 4.8 kbit/s could therefore be a desirable solution for this application, providing also the redundancy that must be added to cope with the channel error rate. After reviewing the mobile-satellite-systems aspects, the paper outlines the features of two different types of vocoders that are likely to be employed, and the relevant methods of assessing their performances. Finally, some results from computer simulations of the speech transmission systems are reported.

  8. 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…

  9. 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...

  10. 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.

  11. Satellite Communications for Aeronautical Applications: Recent research and Development Results

    Science.gov (United States)

    Kerczewski, Robert J.

    2001-01-01

    Communications systems have always been a critical element in aviation. Until recently, nearly all communications between the ground and aircraft have been based on analog voice technology. But the future of global aviation requires a more sophisticated "information infrastructure" which not only provides more and better communications, but integrates the key information functions (communications, navigation, and surveillance) into a modern, network-based infrastructure. Satellite communications will play an increasing role in providing information infrastructure solutions for aviation. Developing and adapting satellite communications technologies for aviation use is now receiving increased attention as the urgency to develop information infrastructure solutions grows. The NASA Glenn Research Center is actively involved in research and development activities for aeronautical satellite communications, with a key emphasis on air traffic management communications needs. This paper describes the recent results and status of NASA Glenn's research program.

  12. Low-noise amplifiers for satellite communications

    Science.gov (United States)

    Whelehan, J.

    1984-02-01

    It is pointed out that over the past several years significant advances have been made in the overall capability of both microwave and mm-wave receivers. This is particularly apparent in the telecom market. Integral parts of advanced receiver technology are low-noise receivers. The advances currently being achieved in low-noise technology are partly based on developments in GaAs semiconductor technology. The development of high-cutoff-frequency beam lead mixer diodes has led to the development of mm-wave low-noise mixers with excellent low-noise capability. The advanced techniques are now being employed in field-deployable systems. Low noise is an important factor in satellite communications applications. Attention is given to C-band fixed satellite service, C-band parametric amplifiers, C-band FET, and X band, the Ku band, and the 30/20 GHz band.

  13. 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.

  14. 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.

  15. The Communications Satellite as Educational Tool.

    Science.gov (United States)

    Long, Peter

    1982-01-01

    Drawing on the experiences of several countries, the author describes satellite technology, discusses the feasibility of satellite use in traditional educational institutions, and analyzes the role of satellites in social development. (SK)

  16. A native IP satellite communications system

    Science.gov (United States)

    Koudelka, O.; Schmidt, M.; Ebert, J.; Schlemmer, H.; Kastner-Puschl, S.; Riedler, W.

    2004-08-01

    ≪ In the framework of ESA's ARTES-5 program the Institute of Applied Systems Technology (Joanneum Research) in cooperation with the Department of Communications and Wave Propagation has developed a novel meshed satellite communications system which is optimised for Internet traffic and applications (L*IP—Local Network Interconnection via Satellite Systems Using the IP Protocol Suite). Both symmetrical and asymmetrical connections are supported. Bandwidth on demand and guaranteed quality of service are key features of the system. A novel multi-frequency TDMA access scheme utilises efficient methods of IP encapsulation. In contrast to other solutions it avoids legacy transport network techniques. While the DVB-RCS standard is based on ATM or MPEG transport cells, the solution of the L*IP system uses variable-length cells which reduces the overhead significantly. A flexible and programmable platform based on Linux machines was chosen to allow the easy implementation and adaptation to different standards. This offers the possibility to apply the system not only to satellite communications, but provides seamless integration with terrestrial fixed broadcast wireless access systems. The platform is also an ideal test-bed for a variety of interactive broadband communications systems. The paper describes the system architecture and the key features of the system.

  17. Wireless communication technology NFC

    OpenAIRE

    MÁROVÁ, Kateřina

    2014-01-01

    Aim of this bachelor thesis is to handle the issue of new wireless communication technology NFC (Near Field Communication) including a comparison of advantages and disadvantages of NFC with other wireless technologies (Bluetooth, Wi-Fi, etc.). NFC is a technology for wireless communications between different electronic devices, one of which is typically a mobile phone. Near Field Communication allows wireless communication at very short distance by approaching or enclosing two devices and can...

  18. A Report on University Applications of Satellite/Cable Technology; First Annual International Communications Conference (Madison, Wisconsin, June 3-5, 1975).

    Science.gov (United States)

    Parker, Lorne A., Comp.; Riccomini, Betsy, Comp.

    The aim of the conference on University Applications of Satellite/Cable Technology was to stimulate discussion among universities, industry, and government on the possibilities of satellite and cable technology in the future. Twenty-six presentations were made covering the following topics: the current status of satellite/cable technology; the…

  19. 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.

  20. Broadband Satellite Technologies and Markets Assessed

    Science.gov (United States)

    Wallett, Thomas M.

    1999-01-01

    The current usage of broadband (data rate greater than 64 kilobits per second (kbs)) for multimedia network computer applications is increasing, and the need for network communications technologies and systems to support this use is also growing. Satellite technology will likely be an important part of the National Information Infrastructure (NII) and the Global Information Infrastructure (GII) in the next decade. Several candidate communications technologies that may be used to carry a portion of the increased data traffic have been reviewed, and estimates of the future demand for satellite capacity have been made. A study was conducted by the NASA Lewis Research Center to assess the satellite addressable markets for broadband applications. This study effort included four specific milestones: (1) assess the changing nature of broadband applications and their usage, (2) assess broadband satellite and terrestrial technologies, (3) estimate the size of the global satellite addressable market from 2000 to 2010, and (4) identify how the impact of future technology developments could increase the utility of satellite-based transport to serve this market.

  1. Satellite-Based Quantum Communications

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, Richard J [Los Alamos National Laboratory; Nordholt, Jane E [Los Alamos National Laboratory; McCabe, Kevin P [Los Alamos National Laboratory; Newell, Raymond T [Los Alamos National Laboratory; Peterson, Charles G [Los Alamos National Laboratory

    2010-09-20

    Single-photon quantum communications (QC) offers the attractive feature of 'future proof', forward security rooted in the laws of quantum physics. Ground based quantum key distribution (QKD) experiments in optical fiber have attained transmission ranges in excess of 200km, but for larger distances we proposed a methodology for satellite-based QC. Over the past decade we have devised solutions to the technical challenges to satellite-to-ground QC, and we now have a clear concept for how space-based QC could be performed and potentially utilized within a trusted QKD network architecture. Functioning as a trusted QKD node, a QC satellite ('QC-sat') could deliver secret keys to the key stores of ground-based trusted QKD network nodes, to each of which multiple users are connected by optical fiber or free-space QC. A QC-sat could thereby extend quantum-secured connectivity to geographically disjoint domains, separated by continental or inter-continental distances. In this paper we describe our system concept that makes QC feasible with low-earth orbit (LEO) QC-sats (200-km-2,000-km altitude orbits), and the results of link modeling of expected performance. Using the architecture that we have developed, LEO satellite-to-ground QKD will be feasible with secret bit yields of several hundred 256-bit AES keys per contact. With multiple ground sites separated by {approx} 100km, mitigation of cloudiness over any single ground site would be possible, potentially allowing multiple contact opportunities each day. The essential next step is an experimental QC-sat. A number of LEO-platforms would be suitable, ranging from a dedicated, three-axis stabilized small satellite, to a secondary experiment on an imaging satellite. to the ISS. With one or more QC-sats, low-latency quantum-secured communications could then be provided to ground-based users on a global scale. Air-to-ground QC would also be possible.

  2. 622 Mbps High-speed satellite communication system for WINDS

    Science.gov (United States)

    Ogawa, Yasuo; Hashimoto, Yukio; Yoshimura, Naoko; Suzuki, Ryutaro; Gedney, Richard T.; Dollard, Mike

    2006-07-01

    WINDS is the experimental communications satellite currently under joint development by Japanese Aerospace Exploration Agency (JAXA) and the National Institute of Information and Communications Technology (NICT). The high-speed satellite communication system is very effective for quick deployment of high-speed networks economically. The WINDS will realize ultra high-speed networking and demonstrate operability of satellite communication systems in high-speed internet. NICT is now developing high-speed satellite communication system for WINDS. High-speed TDMA burst modem with high performance TPC error correction is underdevelopment. Up to the DAC on the transmitter and from the ADC on the receiver, all modem functions are performed in the digital processing technology. Burst modem has been designed for a user data rate up to 1244 Mbps. NICT is developing the digital terminal as a user interface and a network controller for this earth station. High compatibility with the Internet will be provided.

  3. 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

  4. Communication Satellites: Experimental & Operational, Commercial & Public Service.

    Science.gov (United States)

    Development Communication Report, 1979

    1979-01-01

    The title reflects the first and major article in an issue of this newsletter devoted entirely to communication satellites. This series of articles on the potential and applications of communication satellites in development projects is concerned with their development for commercial and public service, development in the Pacific region, SPACECOM…

  5. Industrial communication technology handbook

    CERN Document Server

    Zurawski, Richard

    2005-01-01

    The Industrial Communication Technology Handbook focuses on current and newly emerging communication technologies and systems that are evolving in response to the needs of industry and the demands of industry-led consortia and organizations.Organized into two parts, the text first summarizes the basics of data communications and IP networks, then presents a comprehensive overview of the field of industrial communications. This book extensively covers the areas of fieldbus technology, industrial Ethernet and real-time extensions, wireless and mobile technologies in industrial applications, the

  6. women Contrlbute to Satellite Technology

    Institute of Scientific and Technical Information of China (English)

    1994-01-01

    IN the early morning of August 14, 1992, at the Xichang satellite launching center, China Central Television Station was about to do a live, worldwide broadcast on the launching of an Australian communications satellite made by the United States. With the order of the commander, "Ignition," people could watch the white rocket rise, pierce the blue sky and race toward the space with a long flaming tail trailing behind it.

  7. Privatization of data communication services by domestic satellite in Thailand

    Science.gov (United States)

    Reowilaisuk, Rianchai

    A summary of privatization of satellite communication services in Thailand is presented. A background of satellite communication in Thailand is given. Satellite communication providers, both government and private, are listed. Steps toward privatization and laws governing telecommunications are addressed.

  8. 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

  9. IP技术在卫星通信中的应用及发展趋势%The Application and Developing Trend of IP Technology in Satellite Communication

    Institute of Scientific and Technical Information of China (English)

    程磊; 孔博; 吴久银

    2012-01-01

    Internet Protocol(IP) technology has ubiquitous along with the development of communication,it is one of the hot points in the fields communication that combine IP technology with satellite communication(SATCOM).Addressed the characteristic of SATCOM,the paper analyses the peculiarity of SATCOM link in Internet and presents the im- provement of SATCOM link protocol,then predicts the developing trend of IP technology in SATCOM%随着通信的发展,IP技术已经泛化,将IP技术与卫星通信相结合的卫星IP网络是通信领域众多研究的热点之一。该文针对卫星通信的传输特性,分析了卫星链路在Intemet应用中的特点,介绍了对卫星链路协汉的改进,给出了当前卫星lP网络技术的发展趋势。

  10. A statistical rain attenuation prediction model with application to the advanced communication technology satellite project. 3: A stochastic rain fade control algorithm for satellite link power via non linear Markow filtering theory

    Science.gov (United States)

    Manning, Robert M.

    1991-01-01

    The dynamic and composite nature of propagation impairments that are incurred on Earth-space communications links at frequencies in and above 30/20 GHz Ka band, i.e., rain attenuation, cloud and/or clear air scintillation, etc., combined with the need to counter such degradations after the small link margins have been exceeded, necessitate the use of dynamic statistical identification and prediction processing of the fading signal in order to optimally estimate and predict the levels of each of the deleterious attenuation components. Such requirements are being met in NASA's Advanced Communications Technology Satellite (ACTS) Project by the implementation of optimal processing schemes derived through the use of the Rain Attenuation Prediction Model and nonlinear Markov filtering theory.

  11. 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.

  12. Experimental millimeter-wave satellite communications system

    Science.gov (United States)

    Suzuki, Yoshiaki; Shimada, Masaaki; Arimoto, Yoshinori; Shiomi, Tadashi; Kitazume, Susumu

    This paper describes an experimental system of millimeter-wave satellite communications via Japan's Engineering Test Satellite-VI (ETS-VI) and a plan of experiments. Two experimental missions are planned using ETS-VI millimeter-wave (43/38 GHz bands) transponder, considering the millimeter-wave characteristics such as large transmission capacity and possibility to construct a small earth station with a high gain antenna. They are a personal communication system and an inter-satellite communication system. Experimental system including the configuration and the fundamental functions of the onboard transponder and the outline of the experiments are presented.

  13. 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

  14. Determination of the key parameters affecting historic communications satellite trends

    Science.gov (United States)

    Namkoong, D.

    1984-01-01

    Data representing 13 series of commercial communications satellites procured between 1968 and 1982 were analyzed to determine the factors that have contributed to the general reduction over time of the per circuit cost of communications satellites. The model by which the data were analyzed was derived from a general telecommunications application and modified to be more directly applicable for communications satellites. In this model satellite mass, bandwidth-years, and technological change were the variable parameters. A linear, least squares, multiple regression routine was used to obtain the measure of significance of the model. Correlation was measured by coefficient of determination (R super 2) and t-statistic. The results showed that no correlation could be established with satellite mass. Bandwidth-year however, did show a significant correlation. Technological change in the bandwidth-year case was a significant factor in the model. This analysis and the conclusions derived are based on mature technologies, i.e., satellite designs that are evolutions of earlier designs rather than the first of a new generation. The findings, therefore, are appropriate to future satellites only if they are a continuation of design evolution.

  15. Spacecraft design project: High latitude communications satellite

    Science.gov (United States)

    Josefson, Carl; Myers, Jack; Cloutier, Mike; Paluszek, Steve; Michael, Gerry; Hunter, Dan; Sakoda, Dan; Walters, Wes; Johnson, Dennis; Bauer, Terry

    1989-01-01

    The spacecraft design project was part of AE-4871, Advanced Spacecraft Design. The project was intended to provide experience in the design of all major components of a satellite. Each member of the class was given primary responsibility for a subsystem or design support function. Support was requested from the Naval Research Laboratory to augment the Naval Postgraduate School faculty. Analysis and design of each subsystem was done to the extent possible within the constraints of an eleven week quarter and the design facilities (hardware and software) available. The project team chose to evaluate the design of a high latitude communications satellite as representative of the design issues and tradeoffs necessary for a wide range of satellites. The High-Latitude Communications Satellite (HILACS) will provide a continuous UHF communications link between stations located north of the region covered by geosynchronous communications satellites, i.e., the area above approximately 60 N latitude. HILACS will also provide a communications link to stations below 60 N via a relay Net Control Station (NCS), which is located with access to both the HILACS and geosynchronous communications satellites. The communications payload will operate only for that portion of the orbit necessary to provide specified coverage.

  16. Design and characteristics of a multiband communication satellite antenna system

    Science.gov (United States)

    Ueno, Kenji; Itanami, Takao; Kumazawa, Hiroyuki; Ohtomo, Isao

    1995-04-01

    Feasibility studies on a multiband communication satellite antenna system and the key technologies involved in devising this system are described. The proposed multiband communication satellite utilizes four frequency bands: Ka (30/20 GHz), Ku (14/12 GHz), C (6/4 GHz), and S (2.6/2.5 GHz). It has six beam configurations, three multibeam and three shaped-beam. The following key technologies are presented: (1) a low-loss frequency selective subreflector (FSR) for compact feeds, (2) a low-loss and broadband frequency selective surface (FSS), and (3) a highly accurate and reliable mesh reflector.

  17. Communications technology handbook

    CERN Document Server

    Lewis, Geoff

    2013-01-01

    This is the first point of reference for the communications industries. It offers an introduction to a wide range of topics and concepts encountered in the field of communications technology. Whether you are looking for a simple explanation, or need to go into a subject in more depth, the Communications Technology Handbook provides all the information you need in one single volume.This second edition has been updated to include the latest technology including: Video on DemandWire-less Distribution systemsHigh spee

  18. Satellite Communications: The Indian Scenario

    Directory of Open Access Journals (Sweden)

    Dr. Ranjit Singh

    2014-05-01

    Full Text Available India has launched as many as 73 Indian satellites as of today since its first attempt in 1975. Besides serving traditional markets of telephony and broadcasting, satellites are on the frontiers of advanced applications as telemedicine, distance learning, environment monitoring, remote sensing, and so on. Satellite systems are optimized for services such as Internet access, virtual private networks and personal access. Costs have been coming down in recent years to the point where satellite broadband is becoming competitive. This article is an attempt to view this important topic from Indian perspective. India’s Project GAGAN, GPS Aided Geo Augmented Navigation is discussed.

  19. The Arctic Regional Communications Small SATellite (ARCSAT)

    Science.gov (United States)

    Casas, Joseph; Kress, Martin; Sims, William; Spehn, Stephen; Jaeger, Talbot; Sanders, Devon

    2013-01-01

    Traditional satellite missions are extremely complex and expensive to design, build, test, launch and operate. Consequently many complementary operational, exploration and research satellite missions are being formulated as a growing part of the future space community capabilities using formations of small, distributed, simple to launch and inexpensive highly capable small scale satellites. The Arctic Regional Communications small SATellite (ARCSAT) initiative would launch a Mini-Satellite "Mothership" into Polar or Sun Sync low-earth-orbit (LEO). Once on orbit, the Mothership would perform orbital insertion of four internally stored independently maneuverable nanosatellites, each containing electronically steerable antennas and reconfigurable software-defined radios. Unlike the traditional geostationary larger complex satellite communication systems, this LEO communications system will be comprised of initially a five small satellite formation that can be later incrementally increased in the total number of satellites for additional data coverage. ARCSAT will provide significant enabling capabilities in the Arctic for autonomous voice and data communications relay, Maritime Domain Awareness (MDA), data-extraction from unattended sensors, and terrestrial Search & Rescue (SAR) beacon detection missions throughout the "data starved desert" of the Arctic Region.

  20. 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.

  1. 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.

  2. Program on application of communications satellites to educational development

    Science.gov (United States)

    Morgan, R. P.; Singh, J. P.

    1971-01-01

    Interdisciplinary research in needs analysis, communications technology studies, and systems synthesis is reported. Existing and planned educational telecommunications services are studied and library utilization of telecommunications is described. Preliminary estimates are presented of ranges of utilization of educational telecommunications services for 1975 and 1985; instructional and public television, computer-aided instruction, computing resources, and information resource sharing for various educational levels and purposes. Communications technology studies include transmission schemes for still-picture television, use of Gunn effect devices, and TV receiver front ends for direct satellite reception at 12 GHz. Two major studies in the systems synthesis project concern (1) organizational and administrative aspects of a large-scale instructional satellite system to be used with schools and (2) an analysis of future development of instructional television, with emphasis on the use of video tape recorders and cable television. A communications satellite system synthesis program developed for NASA is now operational on the university IBM 360-50 computer.

  3. Subliminal communication technology

    Science.gov (United States)

    Various types of subliminal communication devices presently in use, the psychological basis for subliminal technology, and the effectiveness of subliminal communication for therapy are examined as well as potentials for abuse. Social, legal, and ethical aspects are considered with respect to the privacy and autonomy of captive audiences. Implications for the regulation of subliminal techniques are reviewed with application to the various media.

  4. Industrial communication technology handbook

    CERN Document Server

    Zurawski, Richard

    2014-01-01

    Featuring contributions from major technology vendors, industry consortia, and government and private research establishments, the Industrial Communication Technology Handbook, Second Edition provides comprehensive and authoritative coverage of wire- and wireless-based specialized communication networks used in plant and factory automation, automotive applications, avionics, building automation, energy and power systems, train applications, and more.New to the Second Edition:46 brand-new chapters and 21 substantially revised chaptersInclusion of the latest, most significant developments in spe

  5. 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.

  6. Communication technology update and fundamentals

    CERN Document Server

    Grant, August E

    2010-01-01

    New communication technologies are being introduced at an astonishing rate. Making sense of these technologies is increasingly difficult. Communication Technology Update and Fundamentals is the single best source for the latest developments, trends, and issues in communication technology. Featuring the fundamental framework along with the history and background of communication technologies, Communication Technology Update and Fundamentals, 12th edition helps you stay ahead of these ever-changing and emerging technologies.As always, every chapter ha

  7. Power versus stabilization for laser satellite communication.

    Science.gov (United States)

    Arnon, S

    1999-05-20

    To establish optical communication between any two satellites, the lines of sight of their optics must be aligned for the duration of the communication. The satellite pointing and tracking systems perform the alignment. The satellite pointing systems vibrate because of tracking noise and mechanical impacts (such as thruster operation, the antenna pointing mechanism, the solar array driver, navigation noise, tracking noise). These vibrations increase the bit error rate (BER) of the communication system. An expression is derived for adaptive transmitter power that compensates for vibration effects in heterodyne laser satellite links. This compensation makes it possible to keep the link BER performance constant for changes in vibration amplitudes. The motivation for constant BER is derived from the requirement for future satellite communication networks with high quality of service. A practical situation of a two-low-Earth-orbit satellite communication link is given. From the results of the example it is seen that the required power for a given BER increases almost exponentially for linear increase in vibration amplitude.

  8. Analysis of Maritime Mobile Satellite Communication Systems

    Science.gov (United States)

    1988-12-01

    Communications and Surveil- lance, IEE, Conference publication n.95, 13-15 Mar. 1973. 2. Y. Karasawa and T. Shiokawa , Characteristics of L-Band Multipath Fading... Shiokawa . Analysis of M-ultipath Fading due to Sea Suface Scattering in Maritime Satellite Communication, Technical Group on Antennas and Propagation. IECE

  9. Satellite Quantum Communication via the Alphasat Laser Communication Terminal

    CERN Document Server

    Elser, Dominique; Khan, Imran; Stiller, Birgit; Marquardt, Christoph; Leuchs, Gerd; Saucke, Karen; Tröndle, Daniel; Heine, Frank; Seel, Stefan; Greulich, Peter; Zech, Herwig; Gütlich, Björn; Richter, Ines; Meyer, Rolf

    2015-01-01

    By harnessing quantum effects, we nowadays can use encryption that is in principle proven to withstand any conceivable attack. These fascinating quantum features have been implemented in metropolitan quantum networks around the world. In order to interconnect such networks over long distances, optical satellite communication is the method of choice. Standard telecommunication components allow one to efficiently implement quantum communication by measuring field quadratures (continuous variables). This opens the possibility to adapt our Laser Communication Terminals (LCTs) to quantum key distribution (QKD). First satellite measurement campaigns are currently validating our approach.

  10. Robust Satellite Communications Under Hostile Interference

    Science.gov (United States)

    2015-01-08

    Gaussian Noise BER Bit Error Rate BLER Block Error Rate BPSK Binary Phase Shift Keying CODEC Coder and Decoder CRC Cyclic Redundancy Check dB...Satellite Communication SNR Signal to Noise Ratio STK Systems Took Kit TDRS Tracking and Data Relay Satellite Toff Idle Time of a Transmitter Ton...Received Signal-to- Noise Ratio at the Jammer ...................................................... 15  3.2.2  SNR Threshold for Repeating the Signal

  11. 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

  12. Quantum Communication Technology

    CERN Document Server

    Gisin, Nicolas

    2010-01-01

    Quantum communication is built on a set of disruptive concepts and technologies. It is driven by fascinating physics and by promising applications. It requires a new mix of competencies, from telecom engineering to theoretical physics, from theoretical computer science to mechanical and electronic engineering. First applications have already found their way to niche markets and university labs are working on futuristic quantum networks, but most of the surprises are still ahead of us. Quantum communication, and more generally quantum information science and technologies, are here to stay and will have a profound impact on the XXI century.

  13. Cockpit weather graphics using mobile satellite communications

    Science.gov (United States)

    Seth, Shashi

    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.

  14. Handbook on satellite communications and broadcasting

    Science.gov (United States)

    Askinazi, G. B.; Bykov, V. L.; Vodopianov, G. V.; D'Iachkova, M. N.; Kantor, L. Ia.; Model, A. M.; Pokras, A. M.; Timofeev, V. V.; Tsirlin, V. M.; Tsirlin, I. S.

    Principles underlying the design and operation of satellite communications systems (SCSs) are reviewed with emphasis on multiple-access techniques. Particular consideration is given to the quality characteristics of CSCs, the frequency ranges assigned to SCSs, an energy analysis of satellite lines, EMC aspects, and the effective utilization of the geostationary orbit. Also examined are the design of earth-station equipment, waveguides and multiplexing equipment, satellite antennas, reliability issues, the Ekran receiving installation, and Gradient-N and Gruppa multiple-access equipment.

  15. An Overview Of Operational Satellites Built By China:Communications Satellites (Part 2)

    Institute of Scientific and Technical Information of China (English)

    Zong He

    2009-01-01

    @@ INNOVATIVE GENERATION: THE DFH-4 PLATFORM AND SATELLITES The DFH-4 platform is the third generation of China-built large geostationary satellite platform with large output power,payload capacity and long service lifetime.Its overall performance ranks with other international advanced satellite platforms.This platform can be used for many services such as high capacity broadcast communication,direct TV broadcasting,digital audio broadcasting and broadband multimedia,which are badly needed for national economic construction and markets both at home and abroad.The platform also has effective technologies that can ensure the security of information transmission.

  16. 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 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...... 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....

  17. Students Partner with Laboratory Staff to Modernize LES-9 Satellite Communications

    Science.gov (United States)

    2016-04-29

    operation, LES-9 continues processing telemetry and exercising the command link. A technological feat of its time, the satellite featured communication at a... communications satellite was developed for the U.S. Air Force and designed to operate in coplanar, circular, inclined, and geosynchronous orbits. Royster...antijam military satellite communications systems.” The LES Operations Center (LESOC) remains preserved in a second-floor B-Building room. Inside, a

  18. Advanced communications technology satellite high burst rate link evaluation terminal power control and rain fade software test plan, version 1.0

    Science.gov (United States)

    Reinhart, Richard C.

    1993-01-01

    The Power Control and Rain Fade Software was developed at the NASA Lewis Research Center to support the Advanced Communications Technology Satellite High Burst Rate Link Evaluation Terminal (ACTS HBR-LET). The HBR-LET is an experimenters terminal to communicate with the ACTS for various experiments by government, university, and industry agencies. The Power Control and Rain Fade Software is one segment of the Control and Performance Monitor (C&PM) Software system of the HBR-LET. The Power Control and Rain Fade Software automatically controls the LET uplink power to compensate for signal fades. Besides power augmentation, the C&PM Software system is also responsible for instrument control during HBR-LET experiments, control of the Intermediate Frequency Switch Matrix on board the ACTS to yield a desired path through the spacecraft payload, and data display. The Power Control and Rain Fade Software User's Guide, Version 1.0 outlines the commands and procedures to install and operate the Power Control and Rain Fade Software. The Power Control and Rain Fade Software Maintenance Manual, Version 1.0 is a programmer's guide to the Power Control and Rain Fade Software. This manual details the current implementation of the software from a technical perspective. Included is an overview of the Power Control and Rain Fade Software, computer algorithms, format representations, and computer hardware configuration. The Power Control and Rain Fade Test Plan provides a step-by-step procedure to verify the operation of the software using a predetermined signal fade event. The Test Plan also provides a means to demonstrate the capability of the software.

  19. 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

  20. Cellular Satellites: Joint Communications With Integrated Acquisition

    Science.gov (United States)

    2015-04-01

    PEO C3T). He has an master’s degree in Business Management from Oklahoma City University, a master’s in National Resource Strategy from the...battlespace.This progress is possible due to the Mobile User Objective System (MUOS), the next-generation narrowband military satellite communication system that...nodes in extreme latitudes. Other demonstrations continue, including assessments of communications perfor- mance with different applications and

  1. Communication Technologies for Vehicles

    DEFF Research Database (Denmark)

    Vinel, Alexey

    This book constitutes the proceedings of the 8th International Workshop on Communication Technologies for Vehicles, Nets4Cars/Nets4Trains/Nets4Aircraft 2015, held in Sousse, Tunisia, in May 2015. The 20 papers presented in this volume were carefully reviewed and selected from 27 submissions...

  2. Wibree: wireless communication technology

    Science.gov (United States)

    Fernandes e Fizardo, Trima Piedade

    2011-12-01

    Nowadays everywhere we come across electronic devices and now the world has become entirely mobile with so many new electronic equipments. The number of computing and telecommunications devices is increasing and consequently the focus on how to connect them to each other. The usual solution is to connect the device with cables or using infra red light to make file transfer and synchronizations possible but infrared light requires line of sight. To solve these problems a new technology,Wibree radio technology complements other local connectivity technologies, consuming only a fraction of the power compared to other radio technologies, enabling smaller and less costly implementations and being easy to integrate with Bluetooth solutions, Furthermore it can be also used to enable communication between several units such as small radio LANs.This paper focuses on why this technology has got large attention although there are pro's and con's with respect to other technologies.

  3. Communication and collaboration technologies.

    Science.gov (United States)

    Cheeseman, Susan E

    2012-01-01

    This is the third in a series of columns exploring health information technology (HIT) in the neonatal intensive care unit (NICU). The first column provided background information on the implementation of information technology throughout the health care delivery system, as well as the requisite informatics competencies needed for nurses to fully engage in the digital era of health care. The second column focused on information and resources to master basic computer competencies described by the TIGER initiative (Technology Informatics Guiding Education Reform) as learning about computers, computer networks, and the transfer of data.1 This column will provide additional information related to basic computer competencies, focusing on communication and collaboration technologies. Computers and the Internet have transformed the way we communicate and collaborate. Electronic communication is the ability to exchange information through the use of computer equipment and software.2 Broadly defined, any technology that facilitates linking one or more individuals together is a collaborative tool. Collaboration using technology encompasses an extensive range of applications that enable groups of individuals to work together including e-mail, instant messaging (IM ), and several web applications collectively referred to as Web 2.0 technologies. The term Web 2.0 refers to web applications where users interact and collaborate with each other in a collective exchange of ideas generating content in a virtual community. Examples of Web 2.0 technologies include social networking sites, blogs, wikis, video sharing sites, and mashups. Many organizations are developing collaborative strategies and tools for employees to connect and interact using web-based social media technologies.3.

  4. Communication, Technology, Temporality

    Directory of Open Access Journals (Sweden)

    Mark A. Martinez

    2012-08-01

    Full Text Available This paper proposes a media studies that foregrounds technological objects as communicative and historical agents. Specifically, I take the digital computer as a powerful catalyst of crises in communication theories and certain key features of modernity. Finally, the computer is the motor of “New Media” which is at once a set of technologies, a historical epoch, and a field of knowledge. As such the computer shapes “the new” and “the future” as History pushes its origins further in the past and its convergent quality pushes its future as a predominate medium. As treatment of information and interface suggest, communication theories observe computers, and technologies generally, for the mediated languages they either afford or foreclose to us. My project describes the figures information and interface for the different ways they can be thought of as aspects of communication. I treat information not as semantic meaning, formal or discursive language, but rather as a physical organism. Similarly an interface is not a relationship between a screen and a human visual intelligence, but is instead a reciprocal, affective and physical process of contact. I illustrate that historically there have been conceptions of information and interface complimentary to mine, fleeting as they have been in the face of a dominant temporality of mediation. I begin with a theoretically informed approach to media history, and extend it to a new theory of communication. In doing so I discuss a model of time common to popular, scientific, and critical conceptions of media technologies especially in theories of computer technology. This is a predominate model with particular rules of temporal change and causality for thinking about mediation, and limits the conditions of possibility for knowledge production about communication. I suggest a new model of time as integral to any event of observation and analysis, and that human mediation does not exhaust the

  5. Communication technology update and fundamentals

    CERN Document Server

    Grant, August E

    2008-01-01

    New communication technologies are being introduced at an astonishing rate. Making sense of these technologies is increasingly difficult. Communication Technology Update is the single best source for the latest developments, trends, and issues in communication technology. Now in its 11th edition, Communication Technology Update has become an indispensable information resource for business, government, and academia. As always, every chapter has been completely rewritten to reflect the latest developments and market statistics, and now covers mobile computing, dig

  6. Antenna technology for advanced mobile communication systems

    Science.gov (United States)

    Rammos, Emmanuel; Roederer, Antoine; Rogard, Roger

    1988-01-01

    The onboard antenna front end is the key subsystem conditioning configuration and performance of mobile communication satellites. The objectives of this paper are to demonstrate this key role and to review L-band satellite antenna technology for earth coverage and regional applications. Multibeam arrays are first discussed, then unfurlable and inflatable reflector antennas are described. These technologies are now qualified in Europe for future mobile systems, for which the optimum choice of antenna technology has been found to be the key to efficient use of spectrum and power resources.

  7. Integrated Performance Optimization of Satellite Communications Constellation

    Institute of Scientific and Technical Information of China (English)

    Chen Xiaoyan; Han Chao

    2011-01-01

    In order to attain better communications performance rather than just expand coverage and save system cost,criteria related to the communications quality and capacity are extracted and revised to build an integrated performance metric system which aims to effectively guide the satellite communications constellation design.These performance metrics together with the system cost serve as the multiple objectives whilst the coverage requirement is regarded as the basic constraint in the optimization of the constellation configuration design applying a revised NSGA-Ⅱ algorithm.The Pareto hypervolumes lead to the best configuration schemes which achieve better integrated system performance compared with the conventional design results based merely on coverage and cost.

  8. Communications satellite system for Africa

    Science.gov (United States)

    Kriegl, W.; Laufenberg, W.

    1980-09-01

    Earlier established requirement estimations were improved upon by contacting African administrations and organizations. An enormous demand is shown to exist for telephony and teletype services in rural areas. It is shown that educational television broadcasting should be realized in the current African transport and communications decade (1978-1987). Radio broadcasting is proposed in order to overcome illiteracy and to improve educational levels. The technical and commercial feasibility of the system is provided by computer simulations which demonstrate how the required objectives can be fulfilled in conjunction with ground networks.

  9. The Communications Satellite - Vehicle for a New Kind of Reciprocal Interdependence in International Adult Education

    Science.gov (United States)

    Wedemeyer, Charles A.

    1971-01-01

    Adult education by means of communication satellites is stressed as a key to reciprocal interdependence. The author states that technological advances such as communications satellites can be used effectively to diffuse knowledge and offer options for choice in evolving societies. (RR)

  10. Intelligent fault isolation and diagnosis for communication satellite systems

    Science.gov (United States)

    Tallo, Donald P.; Durkin, John; Petrik, Edward J.

    1992-01-01

    Discussed here is a prototype diagnosis expert system to provide the Advanced Communication Technology Satellite (ACTS) System with autonomous diagnosis capability. The system, the Fault Isolation and Diagnosis EXpert (FIDEX) system, is a frame-based system that uses hierarchical structures to represent such items as the satellite's subsystems, components, sensors, and fault states. This overall frame architecture integrates the hierarchical structures into a lattice that provides a flexible representation scheme and facilitates system maintenance. FIDEX uses an inexact reasoning technique based on the incrementally acquired evidence approach developed by Shortliffe. The system is designed with a primitive learning ability through which it maintains a record of past diagnosis studies.

  11. Designing the next phase domestic satellites - A step to communication satellites as intelligent network nodes

    Science.gov (United States)

    Majus, J.

    1982-09-01

    Applications of satellite systems for telecommunication networks are discussed in terms of harmonizing the satellite capabilities with ground-based equipment, and design for the satellites are discussed. Modern network services are becoming increasingly digitized and use optic fiber switching and information transfer. Spaceborne nodes can be used for telephony, television, packet switching, leased lines, and teletex, with reserved sectors for point-to-point communications. Space systems are capable of 100% coverage, while terrestrial systems frequently have utilization rates near 5%, implying that demand-oriented satellite expansion of local systems is the suitable methodology. Technological requirements are explored, including exclusive use of digital processing, flexible flow rates, signal transmission times, and short time availability.

  12. 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.

  13. Parametric frequency dividers in satellite communications

    OpenAIRE

    Kosmopoulos, S. A.; Lo Forti, R.; Saggese, E.

    1990-01-01

    The performance of two different parametric frequency dividers, using GaAs varactor diodes in a balanced circuit configuration implemented by planar (microstrip) or quasi-planar (finline, coupled finline ) elements respectively, is presented. The almost phase noise free operation of these devices allows the construction of efficient miniature synthesizers or carrier recovering schemes, incorporated on the space segment of Ku- or Ka-band satellite communications systems.

  14. A guide to the literature on application of communications satellites to educational development

    Science.gov (United States)

    Morgan, R. P.; Singh, J. P.

    1972-01-01

    A review of literature dealing with communication satellite technology is presented for the nontechnical reader with emphasis on the educational aspects. An introduction is provided for: satellite technology; nontechnological aspects including economic, organizational, social, and political factors; and educational and developmental uses. A guide to selected literature, and a bibliography are included.

  15. Communicating with clean technology

    Energy Technology Data Exchange (ETDEWEB)

    Fournier, S.

    1996-09-01

    The potential role of computer-based communications on energy consumption, sustainable development, and the environment were discussed. Various potential benefits derivable from applications such as teleconferencing, videoconferencing, distance-learning, and teleworking as alternatives to travel by car or plane, data transmission by telefax, e-mail, or the Internet, and the resulting effect on paper consumption were cited as examples of how clean computer technology will have significant impact on energy policy and behaviour. It was contended that even if the environmental benefits are not yet promoted as widely as they should be, the increasing danger of air pollution and ozone depletion, combined with the falling cost of telecommunications, productivity gains and improved bottom lines will force the adoption of computer-based communication by mainstream society. 8 refs.

  16. Culture, technology, communication

    DEFF Research Database (Denmark)

    Ess, Charles; Sudweeks, Fay

    The first book-length anthology to collect some of the most significant culturally-oriented research and scholarship on CMC from the biennial conference series "Cultural Attitudes towards Technology and Communication" (CATaC). The collection is significant for its contribution towards calling...... attention to the role of culturally-variable dimensions, including communication preferences, in the design, implementation, and use of ICTs - and thereby helping to bring into the mainstream of related scholarship and research (e.g., HCI, etc.) what was then a novel perspective and series of questions...... and concerns, beginning with the possibility of "computer-mediated colonization," i.e., of imposing culturally-specific preferences and values through the design and implementation of ICTs as then distributed globally....

  17. Space Communication and Navigation Testbed Communications Technology for Exploration

    Science.gov (United States)

    Reinhart, Richard

    2013-01-01

    NASA developed and launched an experimental flight payload (referred to as the Space Communication and Navigation Test Bed) to investigate software defined radio, networking, and navigation technologies, operationally in the space environment. The payload consists of three software defined radios each compliant to NASAs Space Telecommunications Radio System Architecture, a common software interface description standard for software defined radios. The software defined radios are new technology developed by NASA and industry partners. The payload is externally mounted to the International Space Station truss and available to NASA, industry, and university partners to conduct experiments representative of future mission capability. Experiment operations include in-flight reconfiguration of the SDR waveform functions and payload networking software. The flight system communicates with NASAs orbiting satellite relay network, the Tracking, Data Relay Satellite System at both S-band and Ka-band and to any Earth-based compatible S-band ground station.

  18. 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.

  19. DOA estimation for attitude determination on communication satellites

    Institute of Scientific and Technical Information of China (English)

    Yang Bin; He Feng; Jin Jin; Xiong Huagang; Xu Guanghan

    2014-01-01

    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.

  20. Fostering Communicative Competence through Technology

    Directory of Open Access Journals (Sweden)

    Muhammad Aslam Sipra

    2013-05-01

    Full Text Available The article explores the use of technology in EFL classes to promote communicative competence. It elucidates communicative competence and explicates obstructions in communicative tasks. Moreover, it interprets the use of technology in fostering and supporting the development of communicative competence and explains how it is pragmatic in maintaining learners’ level of motivation and interest in learning a foreign language. The present article identifies the significance and use of mobile phone, camera, computer and internet, tape recorder, projector, and language labs in EFL classes. Besides, it discusses the use of technology as an educational tool in language teaching and learning.Keywords: Educational technology, fostering, communicative competence, language teaching, learning

  1. An Active K-Band Receive Slot Array for Mobile Satellite Communications

    Science.gov (United States)

    Tulintseff, A. N.; Lee, K. A.; Sukamto, L. M.; Chew, W.

    1994-01-01

    An active receive slot array has been developed for operation in the downlink frequency band, 19.914-20.064 GHz, of NASA's Advanced Communication Technology Satellite (ACTS) for the ACTS Mobile Terminal (AMT) project.

  2. Transmitter microdischarges in communications and broadcast Satellites

    Science.gov (United States)

    Briskman, Robert D.; Kaliski, Michael A. R.

    2016-09-01

    Most commercial communications and broadcast satellites operating at microwave radio frequencies use traveling wave tube amplifiers (TWTAs) as high power transmitters. Since TWTAs work at high voltages, it is not uncommon to experience micro-discharges, especially early in life. This observation led to the introduction of an autonomous restart function in the companion high voltage power supply (the electronic power conditioner or EPC) of the TWTA as a safety feature. A microdischarge with enough energy above a threshold would lead to a momentary removal of high voltages, followed by an automatic restart, which is usually sufficient to allow the microdischarge event to clear with minimal loss of RF transmission. In most cases the energy involved in the microdischarge is low enough that the removal of high voltages is not required and the event may go undetected. However, an unusual signature was first noted in early 1997 on a Ku-band satellite transmitter, where the characteristics of the microdischarge event were such that the control anode voltage dropped below nominal and typically recovered over a 20 min period. Such microdischarge events became known as the "20 min Effect" which has since been observed over subsequent years on other Ku-band TWTAs, as well as on Ka-band and S-band satellite TWTA transmitters in numerous satellites. This paper summarizes the in-orbit data on such microdischarges as well as the believed cause. In addition, the paper includes results from three S-band TWTAs which have operated on life test for many years. Due to ease of their monitoring instrumentation as contrast to monitoring microdischarges on orbiting operational satellites via telemetry, new data have been accumulated on this effect. The data substantiate the previous findings that microdischarges do not significantly affect satellite operation or their transmissions nor diminish the TWTAs performance, including long lifetime.

  3. A digitally implemented communications experiment utilizing the Hermes (CTS) satellite

    Science.gov (United States)

    Jackson, H. D.; Fiala, J. L.

    1977-01-01

    The Hermes (CTS) experiment program made possible a significant effort directed toward new developments which will reduce the costs associated with the distribution of satellite services. Advanced satellite transponder technology and small inexpensive earth terminals were demonstrated as part of the Hermes program. Another system element that holds promise for reduced transmission cost is associated with the communication link implementation. An experiment is described which uses CTS to demonstrate digital link implementation and its advantages over conventional analog systems. A Digitally Implemented Communications experiment which demonstrates the flexibility and efficiency of digital transmission of television video and audio, telephone voice and high-bit-rate data is also described. Presentation of the experiment concept which concentrates on the evaluation of full-duplex digital television in the teleconferencing environment is followed by a description of unique equipment that was developed.

  4. 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.

  5. 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…

  6. Laser Communication Demonstration System (LCDS) and future mobile satellite services

    Science.gov (United States)

    Chen, Chien-Chung; Wilhelm, Michael D.; Lesh, James R.

    1995-01-01

    The Laser Communications Demonstration System (LCDS) is a proposed in-orbit demonstration of high data rate laser communications technology conceived jointly by NASA and U.S. industry. The program objectives are to stimulate industry development and to demonstrate the readiness of high data rate optical communications in Earth orbit. For future global satellite communication systems using intersatellite links, laser communications technology can offer reduced mass and power requirements and higher channel bandwidths without regulatory constraints. As currently envisioned, LCDS will consist of one or two orbiting laser communications terminals capable of demonstrating high data rate (greater than 750Mbps) transmission in a dynamic space environment. Two study teams led by Motorola and Ball Aerospace are currently in the process of conducting a Phase A/B mission definition study of LCDS under contracts with JPL/NASA. The studies consist of future application survey, concept and requirements definition, and a point design of the laser communications flight demonstration. It is planned that a single demonstration system will be developed based on the study results. The Phase A/B study is expected to be completed by the coming June, and the current results of the study are presented in this paper.

  7. Emerging Technologies: Small Satellite and Associated TPED

    Science.gov (United States)

    Zitz, R.

    2014-09-01

    The 2010 National Space Policy directs the U.S. space community, comprised of the Department of Defense, Intelligence Community, Military Services and NASA to examine our nation's ability to conduct space-based ISR and communications even during a period of peer state and near peer state attacks intended to deny us our advantages we accrue from our use of space systems. DOD and the ICs past experience is largely one of building small numbers of extraordinarily capable and expensive (exquisite) satellites for communications and ISR. As potential adversaries continue to develop cyber-attack capabilities and have demonstrated an ability to kinetically attack spacecraft, the vulnerability of our architecture is now a serious concern. In addition, the sluggish U.S. economy, the draw down and pull back from a decade of combat operations, and other factors have combined to force a significant reduction in DOD and IC spending over the coming decade(s). Simultaneously, DOD and the IC have a growing awareness that the long lead times and long mission duration of the exquisite space assets can lead to fielding technologies that become obsolete and mission limiting. Some DOD and IC leaders are now examining alternative architectures to provide lower cost, flexible, more diverse and rapidly launchable space systems. Government leaders are considering commercially hosted payloads in geosynchronous orbits and smaller, lower cost, free flying government and commercial satellites in low earth orbits. Additional changes to the ground tasking, processing, exploitation and dissemination (TPED) systems would ensure small satellites have end-to-end mission capability and meet emerging needs such as ease of tasking, multi-INT processing, and more advanced distribution mechanisms (e.g., to users on the move). Today, a majority of agency leaders and their subordinate program managers remain convinced that only large, expensive systems can truly answer requirements and provide reliable

  8. Building technological capability within satellite programs in developing countries

    Science.gov (United States)

    Wood, Danielle; Weigel, Annalisa

    2011-12-01

    This paper explores the process of building technological capability in government-led satellite programs within developing countries. The key message is that these satellite programs can learn useful lessons from literature in the international development community. These lessons are relevant to emerging satellite programs that leverage international partnerships in order to establish local capability to design, build and operate satellites. Countries with such programs include Algeria, Nigeria, Turkey, Malaysia and the United Arab Emirates. The paper first provides background knowledge about space activity in developing countries, and then explores the nuances of the lessons coming from the international development literature. Developing countries are concerned with satellite technology because satellites provide useful services in the areas of earth observation, communication, navigation and science. Most developing countries access satellite services through indirect means such as sharing data with foreign organizations. More countries, however, are seeking opportunities to develop satellite technology locally. There are objective, technically driven motivations for developing countries to invest in satellite technology, despite rich debate on this topic. The paper provides a framework to understand technical motivations for investment in satellite services, hardware, expertise and infrastructure in both short and long term. If a country decides to pursue such investments they face a common set of strategic decisions at the levels of their satellite program, their national context and their international relationships. Analysis of past projects shows that countries have chosen diverse strategies to address these strategic decisions and grow in technological capability. What is similar about the historical examples is that many countries choose to leverage international partnerships as part of their growth process. There are also historical examples from

  9. Plan of advanced satellite communications experiment using ETS-VI

    Science.gov (United States)

    Shiomi, Tadashi

    1988-01-01

    Communications Research Laboratory (CRL, Ministry of Posts and Telecommunications, Japan) has been engaged in development of three advanced satellite communication payloads aiming at experiments by Japan's 2-ton class Engineering Test Satellite VI (ETS-VI) which is to be launched in H-II rocket by NASDA in August 1992. CRL's three experimental systems are: (1) S-band inter-satellite communications; (2) millimeter-wave inter-satellite and personal-satellite communications; and (3) optical inter-satellite communications. CRL develops experimental optical communication system with telescope of 75 mm diameter which has gimbal mirror beam pointing/tracking mechanism. The onboard system has fundamental optical communication functions with laser diode transmitter of wavelength 0.83 micron, laser beam point-ahead mechanism, receiver of wavelength 0.51 micron, modulation/demodulation subsystem, and so on.

  10. Cultural Heritage communication technology

    Directory of Open Access Journals (Sweden)

    Elena Ippoliti

    2011-12-01

    Full Text Available This magazine issue is about the relationship between digital techniques and the communication of cultural heritage and specifically aims at portraying how the interest and implications of these two things are widespread. Without trying to go too in depth, various points of view have been compared, each taken from different articles presenting a wide range of possible approaches on the subject of creating a wealth of information on cultural heritage and how it can be made available to the public without difficulty. Therefore, this issue wants to create a forum for a many-sided comparison built on a wealth of experience and opinions of different authors. In this way the abundance and versatility of the contributing professions (architects, archaeologists, engineers, mathematicians, graphic designers, artists, video producers, digital experts, 3D graphic designers, critics, directors, etc. has given life to a precious blend of know-how, which is without doubt enhanced by present-day digital technology.

  11. Technology and social communication

    Energy Technology Data Exchange (ETDEWEB)

    Moore, G.A.

    1996-12-31

    For centuries advances in what we now term media have generated concerns about the effect these advances have on values and morality-books, stage drama, movies, TV, and now computer-based fantasy and Internet-based distribution. These media comprise some of the most powerful agents for developing our fundamental strategies for living. Computer-based fantasy can provide waves of sensations that everyday life does not prepare us for; they create a wow effect. The implications are especially, strong for adolescents. Wow effects come to seem ordinary. We can easily overdose on them with a subsequent dulling of sensibility that motivates one to seek the next level. As the wow effect is numbed, socializing restrictions break down. A psychological strategy of distancing is one defense against enhanced imagery - a strategy of cool as antidote. The wow-cool dipole can foster a role as spectator that inhibits empathy and a fundamental distancing from the self. Technology - the source of our concerns-can also help to counteract them. The most powerful drive in children is to learn mastery of the world. New input and output devices and especially properly designed software can enhance the capacity to learn and to be creative, i.e. to gain mastery over the world. These powerful new modes of communication not only give us great access to the world, they give the world great access to us. We must supplant what is now mostly a passive broadcast system with interactive exploration and two-way communication.

  12. Satellite Networks: Architectures, Applications, and Technologies

    Science.gov (United States)

    Bhasin, Kul (Compiler)

    1998-01-01

    Since global satellite networks are moving to the forefront in enhancing the national and global information infrastructures due to communication satellites' unique networking characteristics, a workshop was organized to assess the progress made to date and chart the future. This workshop provided the forum to assess the current state-of-the-art, identify key issues, and highlight the emerging trends in the next-generation architectures, data protocol development, communication interoperability, and applications. Presentations on overview, state-of-the-art in research, development, deployment and applications and future trends on satellite networks are assembled.

  13. Test using communication satellite for security telecommunication network

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, M.

    1988-01-01

    The authors confirmed by their experiment results that the satellite communication could be practically used for remote monitoring and control in gas distribution systems and data communication not only in emergency but also as the reinforced means of communication network. This report deals with the general description of the security communication network, our experiment of satellite operating system, the results and further plan for the practical application. Their company has started the test on the utilization of a communication satellite (CS-2 Japanese domestic communication satellite) since July, 1984, for the purpose of securing the telecommunication network in case of disaster and applying the satellite communications to data communication suitable for the information age, as for a gas utility industry.

  14. Comparison of INMARSAT and ATS3 satellite communication

    Energy Technology Data Exchange (ETDEWEB)

    1993-03-29

    There exists a need to provide communication through a satellite- based network which allows a user to communicate from a remote site to a fixed site. This discussion provides a comparison, both technical and financial, between the existing ATS3 satellite system and the commercial INMARSAT system. This comparison identified the limitations of each system to provide various types of communication.

  15. 78 FR 14920 - Earth Stations Aboard Aircraft Communicating With Fixed-Satellite Service Geostationary-Orbit...

    Science.gov (United States)

    2013-03-08

    ... forwarding and receiving communications signals via a system of satellites or reselling satellite... specialized telecommunications services, such as satellite tracking, communications telemetry, and radar... of Subjects in 47 CFR Parts 2 and 25 Frequency allocations, Satellites. Federal Communications...

  16. Satellite systems for personal applications concepts and technology

    CERN Document Server

    Richharia, Madhavendra

    2010-01-01

    Presents the concepts, technology, and role of satellite systems in support of personal applications, such as mobile and broadband communications, navigation, television, radio and multimedia broadcasting, safety of life services, etc. This book presents a novel perspective on satellite systems, reflecting the modern personal technology context, and hence a focus on the individual as end-user. The book begins by outlining key generic concepts before discussing techniques adopted in particular application areas; next, it exemplifies these techniques through discussion of state-of-art c

  17. The Role of Communication Satellites in Education and Training: The 1990s.

    Science.gov (United States)

    Polcyn, Kenneth A.

    1981-01-01

    Presents an overview of satellite technology and trends in its use, reviews the evolution of education and training applications of communication satellites, and prognosticates about the possible national and international uses during the 1990s. A bibliography of 26 items is included. (CHC)

  18. The Role of Communication Satellites in Education and Training: The 1990s.

    Science.gov (United States)

    Polcyn, Kenneth A.

    1981-01-01

    Presents an overview of satellite technology and trends in its use, reviews the evolution of education and training applications of communication satellites, and prognosticates about the possible national and international uses during the 1990s. A bibliography of 26 items is included. (CHC)

  19. A Guide to the Literature on Application of Communications Satellites to Educational Development.

    Science.gov (United States)

    Morgan, Robert P.; Singh, Jai P.

    Because of the ability of communications satellites to distribute electronic information (radio, television, digital computer data) over wide areas with potentially attractive costs, considerable interest has been shown in using satellite technology to enhance educational programs, both in the United States and in other countries. In view of these…

  20. ACTS multibeam communications package - Technology for the 1990s

    Science.gov (United States)

    Graebner, John C.; Cashman, William F.

    To maintain its competitive position in the 1990s, satellite communications must evolve to provide new services and to reduce the costs of supplying existing services. NASA's Advanced Communications Technology Satellite (ACTS) program is directed toward developing the technology base that will support this evolution. The ACTS communications payload is optimized for digital communications using a time-division multiple access format. Scanning spot-beam antennas provide high-performance on-demand service to the earth communication stations. On-board processing and switching allow full connectivity in a single-hop network architecture. ACTS employs Ka-band (30/20 GHz) links for communications traffic and includes techniques for mitigating rain fades. Scheduled to be launched by a Space Shuttle in 1992, ACTS will provide in-orbit technology verification and support experimental communications networks for up to four years.

  1. Present and Future Trends in Military Satellite Communication Systems

    Directory of Open Access Journals (Sweden)

    C.K. Chatterjee

    1993-01-01

    Full Text Available Recent years have seen a phenomenal growth in the field of satellite communications. Satcom systems offer many advantages for military applications which include wide area coverage, rapid deployment, flexible networking and long range service to moving platforms like ships, aircraft and vehicles. This paper gives an overview of the special features and future trends in military satcom systems. A brief account of various countermeasures against threats, use of EHF, spread-spectrum techniques and on board processing has also been given. Major technological advances are anticipated in near future to realise high capacity, secure and survivable satcom systems for Defence applications.

  2. Advanced technology for space communications, tracking, and robotic sensors

    Science.gov (United States)

    Krishen, Kumar

    1989-01-01

    Technological advancements in tracking, communications, and robotic vision sensors are reviewed. The development of communications systems for multiple access, broadband, high data rate, and efficient operation is discussed. Consideration is given to the Tracking and Data Relay Satellite systems, GPS, and communications and tracking systems for the Space Shuttle and the Space Station. The use of television, laser, and microwave sensors for robotics and technology for autonomous rendezvous and docking operations are examined.

  3. Use of satellite natural vibrations to improve performance of free-space satellite laser communication.

    Science.gov (United States)

    Arnon, S

    1998-07-20

    In some of the future laser communication satellites, it is plausible to assume that tracking and communication receivers will use the same detector array. The reason for dual use of the detector is to design simpler and less expensive satellites. Satellites vibrate continually because of their subsystems and environmental sources. The vibrations cause nonuniform spreading of the received energy on the detector array. In view of this, the information from the tracking system is used to adapt individually the communication signal gain of each of the detectors in the array. This adaptation of the gains improves communication system performance. It is important to emphasize that the communication performance improvement is achieved only by gain adaptation. Any additional vibrations decrease the tracking and laser pointing system performances, which decrease the return communication performances (two-way communication). A comparison of practical communication systems is presented. The novelty of this research is the utilization of natural satellite vibrations to improve the communication system performance.

  4. TUBSAT-1, satellite technology for educational purposes

    Science.gov (United States)

    Ginati, A.

    1988-01-01

    TUBSAT-1 (Technical University of Berlin Satellite) is an experimental low-cost satellite within the NASA Get Away Special (GAS) program. This project is being financed by the German BMFT (Federal Ministry for Research and Technology), mainly for student education. The dimensions and weight are determined by GAS requirements and the satellite will be ejected from the space shuttle into an approximately 300-km circular orbit. It is a sun/star oriented satellite with an additional spin stabilization mode. The first planned payload is to be used for observing flight paths of migratory birds from northern Europe to southern Africa and back.

  5. Quantum cryptography communication technology

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jai Wan; Choi, Young Soo; Lee, Jae Chul; Choi, Yu Rak; Jung, Gwang Il; Jung, Jong Eun; Hong, Seok Boong; Koo, In Soo

    2007-09-15

    Quantum cryptography communication based on quantum mechanics provides and unconditional security between two users. Even though huge advance has been done since the 1984, having a complete system is still far away. In the case of real quantum cryptography communication systems, an unconditional security level is lowered by the imperfection of the communication unit. It is important to investigate the unconditional security of quantum communication protocols based on these experimental results and implementation examples for the advanced spread all over the world. The Japanese report, titled, 'Investigation report on the worldwide trends of quantum cryptography communications systems' was translated and summarized in this report. An unconditional security theory of the quantum cryptography and real implementation examples in the domestic area are investigated also. The goal of the report is to make quantum cryptography communication more useful and reliable alternative telecommunication infrastructure as the one of the cyber security program of the class 1-E communication system of nuclear power plant. Also another goal of this report is to provide the quantitative decision basis on the quantum cryptography communication when this secure communication system will be used in class 1-E communication channel of the nuclear power plant.

  6. Communication technology update and fundamentals

    CERN Document Server

    Grant, August E

    2014-01-01

    A classic now in its 14th edition, Communication Technology Update and Fundamentals is the single best resource for students and professionals looking to brush up on how these technologies have developed, grown, and converged, as well as what's in store for the future. It begins by developing the communication technology framework-the history, ecosystem, and structure-then delves into each type of technology, including everything from mass media, to computers and consumer electronics, to networking technologies. Each chapter is written by faculty and industry experts who p

  7. A New Approach for Enhanced Communication to LEO Satellites

    NARCIS (Netherlands)

    Gill, E.K.A.; Verhoeven, C.; Gill, K.; De Milliano, M.

    2010-01-01

    Operations of satellites in Low-Earth Orbit (LEO) have been based on exploiting the maximum time of visibility of satellites over their ground stations. In this paper, it is shown that a key parameter for communication between a satellite and a ground station is not the time of visibility but the am

  8. 14/12-GHz-band satellite communication services

    Science.gov (United States)

    Hayashi, Kunihiro; Nagaki, Kiyoaki; Mori, Yasuo

    1990-01-01

    Three new systems for integrated TV-relay services have been developed: Satellite Video Comunication Service (SVCS) and Satellite Digital Communication Service (SDCS), with Japan's 14/12-GHz-band commercial communication satellites. These systems have been in commercial use since May 1989. Usually SVCS and SDCS have been provided using Ka-band (30/20 GHz-band) of CS-2 and Cs-3. This paper provides an overview of the design, the performance, and the systems of the new 14/12-GHz-band satellite communication services.

  9. 基于DVB-RCS的VSAT宽带卫星通信技术与应用%VSAT Broadband Satellite Communications Technology Based on DVB-RCS and its Applications

    Institute of Scientific and Technical Information of China (English)

    郅琦

    2011-01-01

    This paper describes the principles of VSAT data networks,satellite communication systems and the development trend of the broadband DVB-RCS open standard.Through the introduction of VSAT DVB-RCS based broadband satellite communication system in an engineering application examples,including system operations and characteristics,and the basic configuration of the subsystem,it can be concluded that along with broadband networks and services,VSAT satellite communication systems are transforming from the narrowband to broadband system.In the existing technology,based on DVB-RCS standard which has the advantages of openness and low cost,the VSAT broadband satellite communications system will have broad market prospects,especially in the vast remote rural areas.It will be one of the major solutions to the communication problem of the rural areas.%介绍了VSAT数据网原理、卫星通信系统宽带化的发展趋势及DVB-RCS开放标准。通过介绍基于DVB-RCS的VSAT宽带卫星通信系统在工程中的应用实例,其中包括系统业务与特点,以及各子系统的基本配置等,可以得出,随着网络和业务的宽带化,VSAT卫星通信系统正在从传统的窄带向宽带系统转变。在现有技术中,基于DVB-RCS标准因其开放性和较高性价比,在VSAT宽带卫星通信系统中的应用将具有广泛的市场前景,尤其在广大偏远农村地区,将成为解决我国农村通信问题的主要手段之一。

  10. Personal communications via ACTS satellite HBR transponders

    Science.gov (United States)

    Fang, Russell J. F.

    1991-09-01

    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.

  11. Hybrid Global Communication Architecture with Balloons and Satellites

    Science.gov (United States)

    Pignolet, G.; Celeste, A.; Erb, B.

    2002-01-01

    Global space communication systems have been developed now for more than three decades, based mainly on geostationary satellites or almost equivalent systems such as the Molnya orbit concepts. The last decade of the twentieth century has seen the emergence of satellite constellations in low or medium Earth orbit, in order to improve accessibility in terms of visibility at higher latitudes and limited size or power requirement for ground equipment. However such systems are complex to operate, there are still many situations where connection may remain difficult to achieve, and commercial benefits are still to be proven. A new concept, using a network combination of geostationary relay satellites and high altitude stratospheric platforms may well overcome the inconveniences of both geostationary systems and satellite constellations to improve greatly global communication in the future. The emergence of enabling technologies developed in Japan and in several other countries will soon make it possible to fly helium balloons in the upper layers of the atmosphere, at altitudes of 20 km or more. At such an altitude, well above the meteorological disturbances and the jet-streams, the stratosphere enjoys a regular wind at moderate speeds ranging between 10 m/s and 30 m/s, depending on latitude and also on season. It is possible for balloons powered by electric engines to fly non- stop upstream of the wind in order to remain stationary above a particular location. Large balloons, with sizes up to 300 m in length, would be able to carry sub-satellite communication payloads, as well as observation apparatus and scientific equipment. The range of visibility for easy both-way communication between the balloon and operators or customers on the ground could be as large as 200 km in radius. Most current studies consider a combination of solar cells and storage batteries to power the balloons, but microwave beam wireless power transportation from the ground could be a very

  12. A Survey of New Communications Technologies and Their Uses.

    Science.gov (United States)

    Ploman, Edward W.

    The present survey focuses on certain major developments in various countries which are of immediate relevance to the production, distribution, reception and uses of new communications technologies and media; i.e., satellite communications, cable television, videograms and new forms of video-production. Technical explanations have been avoided,…

  13. Radiofrequency testing of satellite segment of simulated 30/20 GHz satellite communications system

    Science.gov (United States)

    Leonard, R. F.; Kerczewski, R.

    1985-01-01

    A laboratory communications system has been developed that can serve as a test bed for the evaluation of advanced microwave (30/20 GHz) components produced under NASA technology programs. The system will ultimately permit the transmission of a stream of high-rate (220 Mbps) digital data from the originating user, through a ground terminal, through a hardware-simulated satellite, to a receiving ground station, to the receiving user. This report contains the results of radiofrequency testing of the satellite portion of that system. Data presented include output spurious responses, attainable signal-to-noise ratios, a baseline power budget, usable frequency bands, phase and amplitude response data for each of the frequency bands, and the effects of power level variation.

  14. Communications Technology--Its Potential.

    Science.gov (United States)

    Ramsay, R. D.

    1981-01-01

    Highlights some of the more significant trends in communications systems and technology, and predicts that the social and educational impact of such changes will be dramatic, with communications becoming more personalized and specialized, and electronics finding its way into nearly all aspects of everyday life. (Author/CHC)

  15. New Voices: Communication through Technology.

    Science.gov (United States)

    Exceptional Parent, 1983

    1983-01-01

    The article recalls working with young severely disabled children able to communicate only through eye movements or specially developed communication boards. These children could now be helped by sophisticated computerized technology, standard and specialized forms of which are described. The influence of positioning, portability, and other…

  16. MEMS technologies for rf communications

    Science.gov (United States)

    Wu, Qun; Kim, B. K.

    2001-04-01

    Microelectromechanical system (MEMS) represents an exciting new technology derived from the same fabricating processes used to make integrated circuits. The trends of growing importance of the wireless communications market is toward the system with minimal size, cost and power consumption. For the purpose of MEMS R&D used for wireless communications, a history and present situation of MEMS device development are reviewed in this paper, and an overview of MEMS research topics on RF communication applications and the state of the art technologies are also presented here.

  17. Baseband processor development for the Advanced Communications Satellite Program

    Science.gov (United States)

    Moat, D.; Sabourin, D.; Stilwell, J.; Mccallister, R.; Borota, M.

    1982-01-01

    An onboard-baseband-processor concept for a satellite-switched time-division-multiple-access (SS-TDMA) communication system was developed for NASA Lewis Research Center. The baseband processor routes and controls traffic on an individual message basis while providing significant advantages in improved link margins and system flexibility. Key technology developments required to prove the flight readiness of the baseband-processor design are being verified in a baseband-processor proof-of-concept model. These technology developments include serial MSK modems, Clos-type baseband routing switch, a single-chip CMOS maximum-likelihood convolutional decoder, and custom LSL implementation of high-speed, low-power ECL building blocks.

  18. The Principle of Navigation Constellation Composed of SIGSO Communication Satellites

    CERN Document Server

    Ji, Hai-Fu; Ai, Guo-Xiang; Shi, Hu-Li

    2012-01-01

    The Chinese Area Positioning System (CAPS), a navigation system based on GEO communication satellites, was developed in 2002 by astronomers at Chinese Academy of Sciences. Extensive positioning experiments of CAPS have been performed since 2005. On the basis of CAPS, this paper studies the principle of navigation constellation composed of Slightly Inclined Geostationary Orbit (SIGSO) communication satellites. SIGSO satellites are derived from end-of-life Geostationary Orbit (GEO) satellites under inclined orbit operation. Considering the abundant frequency resources of SIGSO satellites, multi-frequency observations could be conducted to enhance the precision of pseudorange measurements and ameliorate the positioning performence. The constellation composed of two GEO satellites and four SIGSO satellites with inclination of 5 degrees can provide the most territory of China with 24-hour maximum PDOP less than 42. With synthetic utilization of the truncated precise (TP) code and physical augmentation factor in fo...

  19. Current technologies in vehicular communication

    CERN Document Server

    Dimitrakopoulos, George

    2017-01-01

    This book provides a concise and comprehensive overview of vehicular communication technologies. It classifies all relevant standards, protocols and applications, so as to enable the reader to gain a holistic approach towards the subject of vehicular communications. The primary methods are algorithmic processes and simulation results. First, an overview and classification of vehicular technologies is presented. Then, the book focuses on specific applications of V2V and V2I communications. Special attention is given to recent research and development results regarding R&D projects in the field, in cooperation with car manufacturing companies and universities at a global level. Designed to facilitate understanding of vehicle to vehicle and vehicle to infrastructure technologies, this textbook is appropriate for undergraduate and graduate students of vehicular communications or mobile networks.

  20. Design and analysis of the satellite laser communications network

    Science.gov (United States)

    Ren, Pei-an; Qian, Fengchen; Liu, Qiang; Jin, Linlin

    2015-02-01

    A satellite laser communications network structure with two layers and multiple domains has been proposed, which performance has been simulated by OPENT. To simulation, we design several OPNET models of the network's components based on a satellite constellation with two layers and multiple domains, as network model, node model, MAC layer protocol and optical antenna model. The network model consists of core layer and access layer. The core network consists of four geostationary orbit (GEO) satellites which are uniformly distributed in the geostationary orbit. The access network consists of 6 low Earth orbit (LEO) satellites which is the walker delta (walk-δ) constellation with three orbit planes. In access layer, each plane has two satellites, and the constellation is stably. The satellite constellation presented for space laser network can meet the demand of coverage in the middle and low latitude by a few satellites. Also several terminal device models such as the space laser transmitter, receiver, protocol layer module and optical antenna have been designed according to the inter-satellite links in different orbits t from GEO to LEO or GEO to ground. The influence to network of different transmitting throughput, receiving throughput, network protocol and average time delay are simulated. Simulation results of network coverage, connectivity and traffic load performance in different scenes show that the satellite laser network presented by the paper can be fit for high-speed satellite communications. Such analysis can provide effective reference for the research of satellite laser networking and communication protocol.

  1. Communication on and via technology

    CERN Document Server

    Rothkegel, Annely

    2012-01-01

    The interdependency of technology and communication presents theoreticians as well as practitioners with a wide range of problems. Among the topics discussed in this interdisciplinary volume are: technological knowledge in text and context in combination with cognitive and social conditions, knowledge transfer beyond languages and cultures, the influence of the world wide web on social communities.

  2. Satellite communications application to Pacific countries above Ku band

    Science.gov (United States)

    Iida, Takashi

    1992-01-01

    An application of satellite communications above the Ku band to the Pacific region is described, focusing on: (1) Lightsat system and (2) a high capacity satellite system. A small geostationary satellite system using Ku band for the Federated States of Micronesia is shown as an example. A concept of multi-gigabits/second high capacity communications system using two satellites in the Ka band is described. The onboard bit-by-bit processing is very useful in the low link margin environment due to rain attenuation. These topics were obtained by the Asia Pacific Telecommunications Study granted by NASA conducted by the University of Colorado at Boulder.

  3. 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.

  4. The use of mobile satellite communication terminals

    Science.gov (United States)

    Law, P. A.

    The role of small portable terminals in military satellite systems is examined; the discussion embraces terminals with an antenna reflector diameter of seven meters or less. Emphasis is placed on the specification of MARMOSET (Marconi Mobile Satellite Earth Terminal). Also considered are ship-borne satellite terminals, the improved SCOT terminal, interoperability, reduced downlink power, and reliability and availability.

  5. A Review on Inter-satellite Link in Inter-satellite Optical Wireless Communication

    Science.gov (United States)

    Arora, Heena; Goyal, Rakesh

    2017-06-01

    In this paper, inter-satellite optical wireless communication (IsOWC) system is proposed, one of the imperative utilizations of free space optics/wireless space optics (FSO)/WSO innovation. IsOWC frameworks give a high bandwidth, small size, small weight, low power and minimal effort different option for present microwave satellite frameworks. Optical communications systems have evolved from lengthy fibers to powerful wireless system. This has hence resulted in the use of optical wireless communication system in space communications. As the quantity of satellites circling the Earth expands year by year, a system between the satellites gives a strategy to them to correspond with one another. This is vital for satellites to send data to each other furthermore to hand off the data starting with one satellite then onto the next satellite and after that to the ground stations. By utilizing laser satellite correspondence, the satellites can be joined with information rates up to a few Gbps. The system performance including bit rates, input power, wavelength and distance on an inter-satellite link was analyzed. Various issues such as bit rates, input power, wavelength and distance were presented in IsOWC.

  6. Beyond the Ionosphere: Fifty Years of Satellite Communication

    Science.gov (United States)

    Butrica, Andrew J. (Editor)

    1997-01-01

    The three overlapping stages of satellite communications development outlined provide the three-part framework for the organization of the papers contained in this book. Part 1, 'Passive Origins,' treats the first stage of satellite communications development, extending from the 1940s into the early 1960s, when passive artificial and natural satellites funded by the military and private enterprise established the field. Part 2, 'Creating the Global, Regional, and National Systems,' addresses events that constituted the second stage of development. Early in this stage, which stretched from the 1960s into the 1970s, satellite systems began to make their appearance in the United States, while domestic and international efforts sought to bring order to this new but chaotic, field in the form of Comsat and Intelsat. Part 3, 'The Unfolding of the World System,' explores the development of satellite communications in the remainder of the world, with a strong emphasis on Asia.

  7. INFORMATION COMMUNICATION TECHNOLOGIES

    African Journals Online (AJOL)

    The thesis of this paper is that technology mediated teaching and learning ... abstract, sustainable development, and turn it into reality for all the world's ..... order to underline the fact that online teaching, virtual as it is, it also a highly interac-.

  8. [Wireless human body communication technology].

    Science.gov (United States)

    Sun, Lei; Zhang, Xiaojuan

    2014-12-01

    The Wireless Body Area Network (WBAN) is a key part of the wearable monitoring technologies, which has many communication technologies to choose from, like Bluetooth, ZigBee, Ultra Wideband, and Wireless Human Body Communication (WHBC). As for the WHBC developed in recent years, it is worthy to be further studied. The WHBC has a strong momentum of growth and a natural advantage in the formation of WBAN. In this paper, we first briefly describe the technical background of WHBC, then introduce theoretical model of human-channel communication and digital transmission machine based on human channel. And finally we analyze various of the interference of the WHBC and show the AFH (Adaptive Frequency Hopping) technology which can effectively deal with the interference.

  9. 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.

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

    Science.gov (United States)

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

    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.

  11. 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…

  12. Conformal phased array with beam forming for airborne satellite communication

    NARCIS (Netherlands)

    Schippers, H.; Verpoorte, J.; Jorna, P.; Hulzinga, A.; Meijerink, A.; Roeloffzen, C.G.H.; Heideman, R.G.; Leinse, A.; Wintels, M.

    2008-01-01

    For enhanced communication on board of aircraft novel antenna systems with broadband satellite-based capabilities are required. The installation of such systems on board of aircraft requires the development of a very low-profile aircraft antenna, which can point to satellites anywhere in the upper h

  13. Mobile communications by satellite in Europe - Overview of ESA activities

    Science.gov (United States)

    Rogard, R.; Jongejans, A.; Bartholome, P.

    ESA is conducting studies aimed at the definition of a Land Mobile Satellite System for digital communications within the Western European region, in view of recent market studies indicating the existence of substantial demand for the provision of mobile communications services by satellite. Attention is presently given to the 'Prodat' low-rate system and its ARQ-coding scheme, Prodat's CDMA return link (noting interference protection and spectrum use efficiency criteria) and the aims of Prodat performance trials.

  14. Communication technology update and fundamentals

    CERN Document Server

    Grant, August E

    2012-01-01

    Communication technologies surround us in every part of our lives: via television, web, blogging, mass media, and much more. How do people in business keep up with the latest and greatest trends, and how do they differentiate good information from bad information? How do they get help analyzing information and coming to conclusions about trends that will impact their businesses and business decisions? How do they consider the environmental and sustainability issues surrounding communication technology? This book answers these essential questions. It's for professionals and students working

  15. Myogenic skeletal muscle satellite cells communicate by tunnelling nanotubes.

    Science.gov (United States)

    Tavi, Pasi; Korhonen, Topi; Hänninen, Sandra L; Bruton, Joseph D; Lööf, Sara; Simon, Andras; Westerblad, Håkan

    2010-05-01

    Quiescent satellite cells sit on the surface of the muscle fibres under the basal lamina and are activated by a variety of stimuli to disengage, divide and differentiate into myoblasts that can regenerate or repair muscle fibres. Satellite cells adopt their parent's fibre type and must have some means of communication with the parent fibre. The mechanisms behind this communication are not known. We show here that satellite cells form dynamic connections with muscle fibres and other satellite cells by F-actin based tunnelling nanotubes (TNTs). Our results show that TNTs readily develop between satellite cells and muscle fibres. Once developed, TNTs permit transport of intracellular material, and even cellular organelles such as mitochondria between the muscle fibre and satellite cells. The onset of satellite cell differentiation markers Pax-7 and MyoD expression was slower in satellite cells cultured in the absence than in the presence of muscle cells. Furthermore physical contact between myofibre and satellite cell progeny is required to maintain subtype identity. Our data establish that TNTs constitute an integral part of myogenic cell communication and that physical cellular interaction control myogenic cell fate determination.

  16. 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.

  17. An Alternative for Industrial Arts: Communication Technology.

    Science.gov (United States)

    Maughan, George R., Jr.; Ritz, John M.

    1978-01-01

    Presents a rationale for including the study of communication technology as a part of the general education process in industrial arts. Analyzes communication technology and suggests methods of implementing the technology in industrial arts. (CSS)

  18. Development of Telexistence on a Ship by Using Satellite Communication

    Directory of Open Access Journals (Sweden)

    Noriyuki Sasaki

    2017-03-01

    Full Text Available Nowadays shipping industry has problems such as reduction of mariners, aging of mariners, and labor expenses. To solve the problems, One Person Bridge Operation was developed as navigation supporting system. However, One Person Bridge Operation remained technological problems and one man error. Therefore, in this study, telexistence on a ship was proposed by using satellite communication. Telexistence on a ship is a concept of maneuvering between land and ship with at least two mariners such as navigation officer and helmsman. Navigation officer works on ship as usual and helmsman supports ship from land. In this paper, remote maneuvering system was developed as the first step of telexistence on a ship. For evaluating the effectiveness, ship experiment was carried out. From the result, navigation officer and helmsman could alter ship’s course to 20 degrees within 60 seconds and less than 5% overshoot in the proposed remote maneuvering system.

  19. FEC combined burst-modem for business satellite communications use

    Science.gov (United States)

    Murakami, K.; Miyake, M.; Fuji, T.; Moritani, Y.; Fujino, T.

    The authors recently developed two types of FEC (forward error correction) combined modems both applicable to low-data-rate and intermediate-data-rate TDMA international satellite communications. Each FEC combined modem consists of a QPSK (quadrature phase-shift keyed) modem, a convolutional encoder, and a Viterbi decoder. Both modems are designed taking into consideration the fast acquisition of the carrier and bit timing and the low cycle slipping rate in the low-carrier-to-noise-ratio environment. Attention is paid to designing the Viterbi decoder to be operated in a situation in which successive bursts may have different coding rates according to the punctured coding scheme. The overall scheme of the FEC combined modems are presented, and some of the key technologies applied in developing them are outlined. The hardware implementation and experimentation are also discussed. The measured data are compared with results of theoretical analysis, and relatively good performances are obtained.

  20. Applications of Communications Satellites in Higher Education.

    Science.gov (United States)

    Morgan, Robert P.

    Early experiments with the ATS-1 and ATS-3 satellites utilized one way and two way audio for a variety of university purposes, and several different television modes were employed in the ATS-6 satellite. Among the higher education activities on ATS-6 were inservice teacher education and the facilitation of regionalized medical education. A college…

  1. Propagation Models for Dimensioning and Estimation of Performance and Availability of New Satellite Communication Systems

    OpenAIRE

    2001-01-01

    A rapid growth of new satellite systems utilizing the Ka-band (27 – 40 Ghz) and even higher frequencies is expected in the coming years. The services offered will include broadband communication, interactive broadcasting, multimedia applications, interconnection of local area networks and Internet connectivity. Many of the new systems will use technologies as multiple spot-beams, onboard processing, and switching of packets between beams and inter satellite links. Because of congestion in the...

  2. A Guide to Satellite Communication. Reports and Papers on Mass Communication Number 66.

    Science.gov (United States)

    United Nations Educational, Scientific, and Cultural Organization, Paris (France).

    Basic information about the characteristics, uses, and implications of communication satellites is presented. Characteristics covered include the various types of systems--such as point-to-point, distribution, and broadcasting satellites--and the flexibility, capacity, geographical coverage, cost and disadvantages of satellites. The section on…

  3. 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.

  4. Sperry Univac speech communications technology

    Science.gov (United States)

    Medress, Mark F.

    1977-01-01

    Technology and systems for effective verbal communication with computers were developed. A continuous speech recognition system for verbal input, a word spotting system to locate key words in conversational speech, prosodic tools to aid speech analysis, and a prerecorded voice response system for speech output are described.

  5. New Technologies and Communications Tools

    Science.gov (United States)

    Bouse, Jim

    2016-01-01

    Relationships are key to the success of everything higher education hopes to accomplish, from recruiting the next class to retaining them, guiding them to graduation, creating successful alumni, and fostering satisfied donors. Creation of those relationships can be engaged and facilitated by the technology, communications tools, and ideas…

  6. Communication Technology and Postdivorce Coparenting

    Science.gov (United States)

    Ganong, Lawrence H.; Coleman, Marilyn; Feistman, Richard; Jamison, Tyler; Markham, Melinda Stafford

    2012-01-01

    Divorced individuals who share parenting responsibilities have to figure out ways to work together to raise their children. The purpose of this qualitative study of 49 divorced coparents was to examine how they used technology (e.g., cell phones, computers) to communicate. For parents in effective coparenting relationships, communication…

  7. New Technologies and Communications Tools

    Science.gov (United States)

    Bouse, Jim

    2016-01-01

    Relationships are key to the success of everything higher education hopes to accomplish, from recruiting the next class to retaining them, guiding them to graduation, creating successful alumni, and fostering satisfied donors. Creation of those relationships can be engaged and facilitated by the technology, communications tools, and ideas…

  8. Communication Technology and Postdivorce Coparenting

    Science.gov (United States)

    Ganong, Lawrence H.; Coleman, Marilyn; Feistman, Richard; Jamison, Tyler; Markham, Melinda Stafford

    2012-01-01

    Divorced individuals who share parenting responsibilities have to figure out ways to work together to raise their children. The purpose of this qualitative study of 49 divorced coparents was to examine how they used technology (e.g., cell phones, computers) to communicate. For parents in effective coparenting relationships, communication…

  9. 卫星通信发展展望%Prospect of Satellite Communication Development

    Institute of Scientific and Technical Information of China (English)

    张俊祥

    2012-01-01

    Satellite communication, due to its features of wide area application and flexible networking, has attracted extensive attention and has been used widely since its emergence. In the new century, satellite communication is being updated in technology. By introducing the history of satellite communication and analyzing the characteristics of several current satellite communication systems, the paper presents some hot technologies and applications of satellite communication systems as well as their development trends and developing strategy in the future.%卫星通信由于具有广域性、组网灵活等优良特点,自诞生之日起就得到了广泛关注和应用,进入新世纪后卫星通信正在进行着技术上的换代升级。通过简单回顾卫星通信技术发展的历程,以及对当今几个典型系统技术特点的分析,提出新时期卫星通信系统的技术和应用热点,未来的发展趋势以及应该采用的发展策略。

  10. Land vehicle antennas for satellite mobile communications

    Science.gov (United States)

    Haddad, H. A.; Pieper, B. V.; Mckenna, D. B.

    1985-01-01

    The RF performance, size, pointing system, and cost were investigated concepts are: for a mechanically steered 1 x 4 tilted microstrip array, a mechanically steered fixed-beam conformal array, and an electronically steered conformal phased array. Emphasis is on the RF performance of the tilted 1 x 4 antenna array and methods for pointing the various antennas studied to a geosynchronous satellite. An updated version of satellite isolations in a two-satellite system is presented. Cost estimates for the antennas in quantities of 10,000 and 100,000 unites are summarized.

  11. 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.

  12. Internetworking satellite and local exchange networks for personal communications applications

    Science.gov (United States)

    Wolff, Richard S.; Pinck, Deborah

    1993-01-01

    The demand for personal communications services has shown unprecedented growth, and the next decade and beyond promise an era in which the needs for ubiquitous, transparent and personalized access to information will continue to expand in both scale and scope. The exchange of personalized information is growing from two-way voice to include data communications, electronic messaging and information services, image transfer, video, and interactive multimedia. The emergence of new land-based and satellite-based wireless networks illustrates the expanding scale and trend toward globalization and the need to establish new local exchange and exchange access services to meet the communications needs of people on the move. An important issue is to identify the roles that satellite networking can play in meeting these new communications needs. The unique capabilities of satellites, in providing coverage to large geographic areas, reaching widely dispersed users, for position location determination, and in offering broadcast and multicast services, can complement and extend the capabilities of terrestrial networks. As an initial step in exploring the opportunities afforded by the merger of satellite-based and land-based networks, several experiments utilizing the NASA ACTS satellite and the public switched local exchange network were undertaken to demonstrate the use of satellites in the delivery of personal communications services.

  13. Future large broadband switched satellite communications networks

    Science.gov (United States)

    Staelin, D. H.; Harvey, R. R.

    1979-01-01

    Critical technical, market, and policy issues relevant to future large broadband switched satellite networks are summarized. Our market projections for the period 1980 to 2000 are compared. Clusters of switched satellites, in lieu of large platforms, etc., are shown to have significant advantages. Analysis of an optimum terrestrial network architecture suggests the proper densities of ground stations and that link reliabilities 99.99% may entail less than a 10% cost premium for diversity protection at 20/30 GHz. These analyses suggest that system costs increase as the 0.6 power of traffic. Cost estimates for nominal 20/30 GHz satellite and ground facilities suggest optimum system configurations might employ satellites with 285 beams, multiple TDMA bands each carrying 256 Mbps, and 16 ft ground station antennas. A nominal development program is outlined.

  14. The international maritime satellite communications system INMARSAT (Handbook)

    Science.gov (United States)

    Zhilin, Viktor A.

    The organization and services provided by the INMARSAT satellite communications system are summarized. The structure and operation of the system are described with reference to transmission line parameters, frequency assignment, signals, telex communications, electrical parameters of communication channels, modulation, synchronization, and methods of protection against errors in the transmission of discrete messages. The discussion also covers the principal components of the INMARSAT system and the operation of ship-based stations.

  15. System Design and Key Technologies of the GF-3 Satellite

    Directory of Open Access Journals (Sweden)

    ZHANG Qingjun

    2017-03-01

    Full Text Available GF-3 satellite, the first C band and multi-polarization SAR satellite in China, achieves breakthroughs in a number of core and key technologies. The satellite technology abides by the principle of “Demand Pulls, Technology Pushes”, forming a series of innovation point, and reaching or surpassing international level in main technical specification.

  16. Broadband conformal phased array with optical beam forming for airborne satellite communication

    NARCIS (Netherlands)

    Schippers, H.; Verpoorte, J.; Jorna, P.; Hulzinga, A.; Meijerink, A.; Roeloffzen, C.G.H.; Zhuang, L.; Marpaung, D.A.I.; Etten, van W.; Heideman, R.G.; Leinse, A.; Borreman, A.; Hoekman, M.; Wintels, M.

    2008-01-01

    For enhanced communication on board an aircraft, novel antenna systems with broadband satellite based capabilities are required. The technology will enhance airline operations by providing in-flight connectivity for flight crew information and will bring live TV and high speed Internet connectivity

  17. Research on key technology of space laser communication network

    Science.gov (United States)

    Chang, Chengwu; Huang, Huiming; Liu, Hongyang; Gao, Shenghua; Cheng, Liyu

    2016-10-01

    Since the 21st century, Spatial laser communication has made a breakthrough development. Europe, the United States, Japan and other space powers have carried out the test of spatial laser communication technology on-orbit, and put forward a series of plans. In 2011, China made the first technology demonstration of satellite-ground laser communication carried by HY-2 satellite. Nowadays, in order to improve the transmission rate of spatial network, the topic of spatial laser communication network is becoming a research hotspot at home and abroad. This thesis, from the basic problem of spatial laser communication network to solve, analyzes the main difference between spatial network and ground network, which draws forth the key technology of spatial laser communication backbone network, and systematically introduces our research on aggregation, addressing, architecture of spatial network. From the perspective of technology development status and trends, the thesis proposes the development route of spatial laser communication network in stages. So as to provide reference about the development of spatial laser communication network in China.

  18. Destination directed packet switch architecture for a geostationary communication satellite network

    Science.gov (United States)

    Ivancic, W. D.; Shalkhauser, M. J.; Bobinsky, E. A.; Soni, N. J.; Quintana, J. A.; Kim, H.; Wagner, P.; Vanderaar, M.

    1992-01-01

    A major effort at NASA/Lewis is to identify and develop critical digital technologies and components that enable new commercial missions or significantly improve the performance, cost efficiency, and/or reliability of existing and planned space comunications systems. NASA envisions the need for low data rate, direct to the user communications services, for data, facsimile, voice, and video conferencing. A report that focuses on destination directed packet switching architectures for geostationary communication satellites is presented.

  19. Destination directed packet switch architecture for a geostationary communication satellite network

    Science.gov (United States)

    Ivancic, W. D.; Shalkhauser, M. J.; Bobinsky, E. A.; Soni, N. J.; Quintana, J. A.; Kim, H.; Wagner, P.; Vanderaar, M.

    1992-08-01

    A major effort at NASA/Lewis is to identify and develop critical digital technologies and components that enable new commercial missions or significantly improve the performance, cost efficiency, and/or reliability of existing and planned space comunications systems. NASA envisions the need for low data rate, direct to the user communications services, for data, facsimile, voice, and video conferencing. A report that focuses on destination directed packet switching architectures for geostationary communication satellites is presented.

  20. Communicating in English for Science and Technology

    DEFF Research Database (Denmark)

    Mousten, Birthe

    Communicating in English for Science and Technology covers some of the most important questions in connection with communication models, stylistics and genre conventions within the area of English used in science and technology texts. Moreover,knowledge management, terminology management...

  1. APPLICATION OF VISION METROLOGY TO IN-ORBIT MEASUREMENT OF LARGE REFLECTOR ONBOARD COMMUNICATION SATELLITE FOR NEXT GENERATION MOBILE SATELLITE COMMUNICATION

    Directory of Open Access Journals (Sweden)

    M. Akioka

    2016-06-01

    Full Text Available 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. 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

  3. 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.

  4. 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.

  5. Impact of information technology on business communication

    Directory of Open Access Journals (Sweden)

    Zvonimir Jurković

    2013-12-01

    Full Text Available Business communication is a very important part of any business, organization and management system, while information technology merges microelectronics, computers, telecommunications and software, thus facilitating the input, processing and distribution of information. Information technology is one of the key generic technologies because it has entered all spheres of economic, scientific, social and private life and has brought with it radical changes. Different information technologies and communication are closely linked. The new business communication using Web 2.0 technology defines active factors in a completely new business communication environment. For the new approach to business communication to be effective, a good knowledge of various communication technologies is required. The aim of this paper is to present contemporary business communication and demonstrate how much information technology affects business communication using a practical example (private business.

  6. A figure of merit for competing communications satellite designs

    Science.gov (United States)

    Lovell, R. R.; Fordyce, S. W.

    1983-01-01

    Trends in launch schedules, weights, power, and space segment costs per transponder year for Intelsats and North American domsats (domestic communications satellites) are discussed. The Intelsat system currently services 25,000 point to point telephone links at any one moment, and a $3 billion order has been placed for Intelsat VIs, which feature 36,000 telephone circuits each. The Intelsat VI spacecraft will weigh 1670 kg in orbit, a continuance of the trend to heavier satellites, while the domsats will stay at 650 kg due to launch vehicle limitations. Direct television broadcast satellites are being designed for receive only (R/O) earth stations, with each satellite capable of servicing 50,000 individual ground stations. Competition is growing for C and Ku band satellite transponders for DBS, with costs $350,000 each. No standardized design has yet emerged.

  7. Satellite utilization for educational communications in the U.S.

    Science.gov (United States)

    Morgan, R. P.; Singh, J. P.

    1974-01-01

    This paper summarizes completed, continuing and planned satellite experiments in the U.S. related to the delivery of educational services and networking. It also describes some results of an on-going study at Washington University directed towards defining applications of fixed/broadcast communication satellites in the U.S. and alternative systems and strategies for large-scale telecommunication-based educational delivery systems utilizing satellites. An analysis is presented of recent actions which may influence future development of such systems.

  8. Interference susceptibility measurements for an MSK satellite communication link

    Science.gov (United States)

    Kerczewski, Robert J.; Fujikawa, Gene

    1992-01-01

    The results are presented of measurements of the degradation of an MSK satellite link due to modulated and CW (unmodulated) interference. These measurements were made using a hardware based satellite communication link simulator at NASA-Lewis. The results indicate the amount of bit error rate degradation caused by CW interference as a function of frequency and power level, and the degradation caused by adjacent channel and cochannel modulated interference as a function of interference power level. Results were obtained for both the uplink case (including satellite nonlinearity) and the downlink case (linear channel).

  9. A Survey of Satellite Communications System Vulnerabilities

    Science.gov (United States)

    2008-06-01

    Myers, Raymond M. Nuber, Jaime L. Prieto , Jr., and Eric R. Wiswell, “Fast Packet Vs. Circuit Switch and Bent Pipe Satellite Network Architectures...2008. 81. Howell, Alan , “INMARSAT HORIZONS PROGRAM,” Institution of Electrical Engineers, Savoy Place, London, 1998. 82. http://www.infosec.gov.hk...ntia-rpt/02- 393/02-393.pdf, NTIA Report 02-393, pages 1-20, May 2002. 134. Sardella, Alan , “Securing Provider Backbone Networks: Packet Filters

  10. Emerging Communication Technologies (ECT) Phase 4 Report

    Science.gov (United States)

    Bastin, Gary L.; Harris, William G.; Marin, Jose A.; Nelson, Richard A.

    2005-01-01

    The Emerging Communication Technology (ECT) project investigated three First Mile communication technologies in support of NASA s Crew Exploration Vehicle (CEV), Advanced Range Technology Working Group (ARTWG), and the Advanced Spaceport Technology Working Group (ASTWG). These First Mile technologies have the purpose of interconnecting mobile users with existing Range Communication infrastructures on a 24/7 basis. ECT is a continuation of the Range Information System Management (RISM) task started in 2002. This is the fourth year of the project.

  11. An Analysis of Marine Corps Beyond Line of Sight Wideband Satellite Communications Requirements

    Science.gov (United States)

    2010-09-01

    Network (SWAN) ............................................40 9. Tropo /Satellite Support Radio (TSSR) ............................................42...Service Tactical Communications Program TROPO ...tropospheric scatter TSSR..................................................tropospheric scatter ( TROPO )-satellite support radio TSST

  12. Terahertz Science, Technology, and Communication

    Science.gov (United States)

    Chattopadhyay, Goutam

    2013-01-01

    The term "terahertz" has been ubiquitous in the arena of technology over the past couple of years. New applications are emerging every day which are exploiting the promises of terahertz - its small wavelength; capability of penetrating dust, clouds, and fog; and possibility of having large instantaneous bandwidth for high-speed communication channels. Until very recently, space-based instruments for astrophysics, planetary science, and Earth science missions have been the primary motivator for the development of terahertz sensors, sources, and systems. However, in recent years the emerging areas such as imaging from space platforms, surveillance of person-borne hidden weapons or contraband from a safe stand-off distance and reconnaissance, medical imaging and DNA sequencing, and in the world high speed communications have been the driving force for this area of research.

  13. 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.

  14. NASA to launch second business communications satellite

    Science.gov (United States)

    1981-01-01

    The two stage Delta 3910 launch vehicle was chosen to place the second small business satellite (SBS-B) into a transfer orbit with an apogee of 36,619 kilometers and a perigee of 167 km, at an inclination of 27.7 degrees to Earth's equator. The firing and separation sequence and the inertial guidance system are described as well as the payload assist module. Facilities and services for tracking and control by NASA, COMSAT, Intelsat, and SBS are outlined and prelaunch operations are summarized.

  15. High-precision satellite relative-trajectory simulating servosystem for inter-satellite laser communications

    Science.gov (United States)

    Zhang, Lei; Liu, Liren; Luan, Zhu; Liu, Hongzhan; Xu, Rongwei

    2004-10-01

    Because PAT (pointing-acquisition-tracking) parameters and integrated technical specifications of laser communication terminals for inter-satellite link must be pre-verified and assessed thoroughly on a ground-based test-bed before launched into the space, it is necessary to develop a system as a primary part of the test bed to simulate the relative trajectory between the satellites. In this paper, an original high-precision satellite relative-trajectory simulating servosystem is introduced in detail as well as its structures and characteristics. The system is used to simulate the motion of relative-trajectory between satellites in different orbits. The principle of the system is to import the data of two satellites" orbits into a computer-based control system in advance. After processed and analyzed, the data is transformed into the angular displacement of the servomotor which drives the gimbal directly. The angular displacement of the two axes of the gimbal can simulate precisely the relative-trajectory, namely elevation angle and azimuth angle of the two satellites in communication. A laser communication terminal mounted on the gimbal then performs the PAT mechanisms to evaluate the system"s capacity.

  16. A digitally implemented communications experiment utilizing the Hermes /CTS/ satellite

    Science.gov (United States)

    Jackson, H. D.; Fiala, J.

    1977-01-01

    Attention is given to an investigation being conducted by NASA-Lewis and Comsat Laboratories which uses the Hermes (CTS) satellite to explain digital link implementation and the advantages it provides over conventional analog systems. The experiment concentrates on developing several video, audio, and data digital communications techniques.

  17. Uplink Power Control For Earth/Satellite/Earth Communication

    Science.gov (United States)

    Chakraborty, Dayamoy

    1994-01-01

    Proposed control subsystem adjusts power radiated by uplink transmitter in Earth station/satellite relay station/ Earth station communication system. Adjustments made to compensate for anticipated changes in attenuation by rain. Raw input is a received downlink beacon singal, amplitude of which affected not only by rain fade but also by scintillation, attenuation in atmospheric gases, and diurnal effects.

  18. Architectures for ku-band broadband airborne satellite communication antennas

    NARCIS (Netherlands)

    Verpoorte, Jaco; Schippers, Harmen; Jorna, Pieter; Roeloffzen, Chris G.H.; Marpaung, David A.I.; Baggen, Rens; Sanadgol, Bahram

    2010-01-01

    This paper describes different architectures for a broadband antenna for satellite communication on aircraft. The antenna is a steerable (conformal) phased array antenna in Ku-band (receive-only). First the requirements for such a system are addressed. Subsequently a number of potential architecture

  19. An Orbiting Standards Platform for communication satellite system RF measurements

    Science.gov (United States)

    Wallace, R. G.; Woodruff, J. J.

    1978-01-01

    The Orbiting Standards Platform (OSP) is a proposed satellite dedicated to performing RF measurements on space communications systems. It would consist of a quasi-geostationary spacecraft containing an ensemble of calibrated RF sources and field strength meters operating in several microwave bands, and would be capable of accurately and conveniently measuring critical earth station and satellite RF performance parameters, such as EIRP, gain, figure of merit (G/T), crosspolarization, beamwidth, and sidelobe levels. The feasibility and utility of the OSP concept has been under joint study by NASA, NBS, Comsat and NTIA. A survey of potential OSP users was conducted by NTIA as part of this effort. The response to this survey, along with certain trends in satellite communications system design, indicates a growing need for such a measurement service.

  20. The principle of the positioning system based on communication satellites

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    It is a long dream to realize the communication and navigation functionality in a satellite system in the world. This paper introduces how to establish the system, a positioning system based on communication satellites called Chinese Area Positioning System (CAPS). Instead of the typical navigation satellites, the communication satellites are configured firstly to transfer navigation signals from ground stations, and can be used to obtain service of the positioning, velocity and time, and to achieve the function of navigation and positioning. Some key technique issues should be first solved; they include the accuracy position determination and orbit prediction of the communication satellites, the measur- ing and calculation of transfer time of the signals, the carrier frequency drift in communication satellite signal transfer, how to improve the geometrical configuration of the constellation in the system, and the integration of navigation & communication. Several innovative methods are developed to make the new system have full functions of navigation and communication. Based on the development of crucial techniques and methods, the CAPS demonstration system has been designed and developed. Four communication satellites in the geosynchronous orbit (GEO) located at 87.5°E, 110.5°E, 134°E, 142°E and barometric altimetry are used in the CAPS system. The GEO satellites located at 134°E and 142°E are decommissioned GEO (DGEO) satellites. C-band is used as the navigation band. Dual frequency at C1=4143.15 MHz and C2=3826.02 MHz as well as dual codes with standard code (CA code and precision code (P code)) are adopted. The ground segment consists of five ground stations; the master station is in Lintong, Xi’an. The ground stations take a lot of responsibilities, including monitor and management of the operation of all system components, determination of the satellite position and prediction of the satellite orbit, accomplishment of the virtual atomic clock

  1. 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.

  2. Integrated Cryogenic Satellite Communications Cross-Link Receiver Experiment

    Science.gov (United States)

    Romanofsky, R. R.; Bhasin, K. B.; Downey, A. N.; Jackson, C. J.; Silver, A. H.; Javadi, H. H. S.

    1995-01-01

    An experiment has been devised which will validate, in space, a miniature, high-performance receiver. The receiver blends three complementary technologies; high temperature superconductivity (HTS), pseudomorphic high electron mobility transistor (PHEMT) monolithic microwave integrated circuits (MMIC), and a miniature pulse tube cryogenic cooler. Specifically, an HTS band pass filter, InP MMIC low noise amplifier, HTS-sapphire resonator stabilized local oscillator (LO), and a miniature pulse tube cooler will be integrated into a complete 20 GHz receiver downconverter. This cooled downconverter will be interfaced with customized signal processing electronics and integrated onto the space shuttle's 'HitchHiker' carrier. A pseudorandom data sequence will be transmitted to the receiver, which is in low Earth orbit (LEO), via the Advanced Communication Technology Satellite (ACTS) on a 20 GHz carrier. The modulation format is QPSK and the data rate is 2.048 Mbps. The bit error rate (BER) will be measured in situ. The receiver is also equipped with a radiometer mode so that experiment success is not totally contingent upon the BER measurement. In this mode, the receiver uses the Earth and deep space as a hot and cold calibration source, respectively. The experiment closely simulates an actual cross-link scenario. Since the receiver performance depends on channel conditions, its true characteristics would be masked in a terrestrial measurement by atmospheric absorption and background radiation. Furthermore, the receiver's performance depends on its physical temperature, which is a sensitive function of platform environment, thermal design, and cryocooler performance. This empirical data is important for building confidence in the technology.

  3. Commercial and Military Communication Satellite Acquisition Practices.

    Science.gov (United States)

    1985-05-01

    1.83 69 F-5 Ivf 0 0.00 na na F-6 1/70 - 3/71 6 1.70 0.33 19 F-7 4/70 - 1/72 0 0.00 Ila la F-8 amf 0 0.00 Ila na I S AT- IV F-I 5/7 5 - 11/82 7 4.82 4.82...Air Force but integration, especi- ally the development of electronics buffers to integrate the encryption devices into the satellite electronics, was...of a nature similar to DSCS-II, so these should roughly cancel out. The electronics buffer interface to the encryption boxes and nuclear hardening

  4. Economically sustainable public security and emergency network exploiting a broadband communications satellite

    OpenAIRE

    Lawal, Lasisi Salami

    2014-01-01

    The research contributes to work in Rapid Deployment of a National Public Security and Emergency Communications Network using Communication Satellite Broadband. Although studies in Public Security Communication networks have examined the use of communications satellite as an integral part of the Communication Infrastructure, there has not been an in-depth design analysis of an optimized regional broadband-based communication satellite in relation to the envisaged service coverage area, with l...

  5. The principle of the positioning system based on communication satellites

    Institute of Scientific and Technical Information of China (English)

    AI GuoXiang; SHI HuLi; WU HaiTao; LI ZhiGang; GUO Ji

    2009-01-01

    It is a long dream to realize the communication and navigation functionality in a satellite system in the world.This paper introduces how to establish the system,a positioning system based on communication satellites called Chinese Area Positioning System (CAPS).Instead of the typical navigation satelIites,the communication satellites are configured firstly to transfer navigation signals from ground stations,and can be used to obtain service of the positioning,velocity and time,and to achieve the function of navigation and positioning.Some key technique issues should be first solved; they include the accuracy position determination and orbit prediction of the communication satellites,the measuring and calculation of transfer time of the signals,the carrier frequency drift in communication satellite ignal transfer,how to improve the geometrical configuration of the constellation in the system,and the integration of navigation & communication.Several innovative methods are developed to make the new system have full functions of navigation and communication.Based on the development of crucial techniques and methods,the CAPS demonstration system has been designed and developed.Four communication satellites in the geosynchronous orbit (GEO) located at 87.5°E,110.5°E,134°E,142°E and barometric altimetry are used in the CAPS system.The GEO satellites located at 134°E and 142°E re decommissioned GEO (DGEO) satellites.C-band is used as the navigation band.Dual frequency at C1=4143.15 MHz and C2=3826.02 MHz as well as dual codes with standard code (CA code and precision code (P code)) are adopted.The ground segment consists of five ground stations; the master station is in Lintong,Xi'an.The ground stations take a lot of responsibilities,including monitor and management of the operation of all system components,determination of the satellite position and prediction of the satellite orbit,accomplishment of the virtual atomic clock measurement,transmission and receiving

  6. Communications Satellites: A New Channel for International Communications, A New Source of International Tension.

    Science.gov (United States)

    Mickelson, Sig

    Communications satellites could be the subject of bitter and potentially dangerous international controversy. They threaten to upset the comfortable monopoly of internal national communications systems which have enrolled national governments to screen intrusions of unwanted information or ideas. The United Nations Working Committee on Direct…

  7. 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...

  8. Information and Communication Technology Application in ...

    African Journals Online (AJOL)

    Information and Communication Technology Application in Collection Development ... The library is the heart and life-line of any citadel of learning. ... promotes quick delivery of information materials, enhances communication with publishers ...

  9. A system for the simulation and evaluation of satellite communication networks

    Science.gov (United States)

    Bagwell, J. W.

    1984-01-01

    With the emergence of a new era in satellite communications, brought about by NASA's thrust into the Ka band with multibeam and onboard processing technologies, new and innovative techniques for evaluating these concepts and systems are required. To this end, NASA, in conjunction with its extensive program for advanced communications technology development, has undertaken to develop a concept for the simulation and evaluation of a complete communications network. Incorporated in this network will be proof-of-concept models of the latest technologies proposed for future satellite communications systems. These include low noise receivers, matrix switches, baseband processors, and solid state and tube type high power amplifiers. To accomplish this, numerous supporting technologies must be added to those aforementioned proof-of-concept models. These include controllers for synchronization, order wire, resource allocation, gain compensation, signal leveling, power augmentation, and rain fade and range delay simulation. Taken together, these will be assembled to comprise a system capable of addressing numerous design and performance questions. The simulation and evaluation system, as planned, will be modular in design and implementation, capable of modification and updating to track and evaluate a continuum of emerging concepts and technologies. Previously announced in STAR as N84-13400

  10. Aerospace Communications Security Technologies Demonstrated

    Science.gov (United States)

    Griner, James H.; Martzaklis, Konstantinos S.

    2003-01-01

    In light of the events of September 11, 2001, NASA senior management requested an investigation of technologies and concepts to enhance aviation security. The investigation was to focus on near-term technologies that could be demonstrated within 90 days and implemented in less than 2 years. In response to this request, an internal NASA Glenn Research Center Communications, Navigation, and Surveillance Aviation Security Tiger Team was assembled. The 2-year plan developed by the team included an investigation of multiple aviation security concepts, multiple aircraft platforms, and extensively leveraged datalink communications technologies. It incorporated industry partners from NASA's Graphical Weather-in-the-Cockpit research, which is within NASA's Aviation Safety Program. Two concepts from the plan were selected for demonstration: remote "black box," and cockpit/cabin surveillance. The remote "black box" concept involves real-time downlinking of aircraft parameters for remote monitoring and archiving of aircraft data, which would assure access to the data following the loss or inaccessibility of an aircraft. The cockpit/cabin surveillance concept involves remote audio and/or visual surveillance of cockpit and cabin activity, which would allow immediate response to any security breach and would serve as a possible deterrent to such breaches. The datalink selected for the demonstrations was VDL Mode 2 (VHF digital link), the first digital datalink for air-ground communications designed for aircraft use. VDL Mode 2 is beginning to be implemented through the deployment of ground stations and aircraft avionics installations, with the goal of being operational in 2 years. The first demonstration was performed December 3, 2001, onboard the LearJet 25 at Glenn. NASA worked with Honeywell, Inc., for the broadcast VDL Mode 2 datalink capability and with actual Boeing 757 aircraft data. This demonstration used a cockpitmounted camera for video surveillance and a coupling to

  11. 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

  12. Wireless communication technologies in distribution automation

    Energy Technology Data Exchange (ETDEWEB)

    Takala, J. [VTT Energy, Espoo (Finland)

    1996-12-31

    The project examines four different wireless communication technologies: GSM short message service, NMT data calls, packet radio network, Autonet (Actionet) status message service. The targets for communication include: energy measurement, especially in the de-regulated electricity market, secondary sub-station control, fault indicators. The research concentrates on the usability of different communication technologies for different purposes. Data about response times, error rates, retry times, communication delays, costs etc. will be collected for each communication technology and comparative results will be obtained. Some field experiments and demonstrations will be made in energy measurement and distribution network remote control. The project is divided in four tasks. Each task is described briefly

  13. 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.

  14. 77 FR 58579 - Certain Two-Way Global Satellite Communication Devices, System and Components Thereof...

    Science.gov (United States)

    2012-09-21

    ... COMMISSION Certain Two-Way Global Satellite Communication Devices, System and Components Thereof; Institution...-way global satellite communication devices, system and components thereof by reason of infringement of... after importation of certain two-way global satellite communication devices, system and components...

  15. 78 FR 31576 - Enforcement Proceeding; Certain Two-Way Global Satellite Communication Devices, System and...

    Science.gov (United States)

    2013-05-24

    ... Proceeding; Certain Two-Way Global Satellite Communication Devices, System and Components Thereof; Notice of... United States after importation of certain two-way global satellite communication devices, system and... States after importation any two-way global satellite communication devices, system, and components...

  16. Introduction. Aging, Communication and Media Technologies

    OpenAIRE

    Kim Sawchuk

    2016-01-01

    What does it mean to age within “networked societies” (Castells, 2000)? What might be learned if we take the Internet and Communication Technology (ICT) and media experiences of older adults into account in our research? These questions are core to this special issue on Aging, Communication and Media Technologies. Comprised of six papers from authors working in five cultural contexts in Europe and North America, Aging, Communication and Media Technologies offers insights into demographic tran...

  17. Information Communication Technology Planning in Developing Countries

    Science.gov (United States)

    Malapile, Sandy; Keengwe, Jared

    2014-01-01

    This article explores major issues related to Information Communication Technology (ICT) in education and technology planning. Using the diffusion of innovation theory, the authors examine technology planning opportunities and challenges in Developing countries (DCs), technology planning trends in schools, and existing technology planning models…

  18. Information Communication Technology Planning in Developing Countries

    Science.gov (United States)

    Malapile, Sandy; Keengwe, Jared

    2014-01-01

    This article explores major issues related to Information Communication Technology (ICT) in education and technology planning. Using the diffusion of innovation theory, the authors examine technology planning opportunities and challenges in Developing countries (DCs), technology planning trends in schools, and existing technology planning models…

  19. Satellite communications provisions on NASA Ames instrumented aircraft platforms for Earth science research/applications

    Science.gov (United States)

    Shameson, L.; Brass, J. A.; Hanratty, J. J.; Roberts, A. C.; Wegener, S. S.

    1995-01-01

    Earth science activities at NASA Ames are research in atmospheric and ecosystem science, development of remote sensing and in situ sampling instruments, and their integration into scientific research platform aircraft. The use of satellite communications can greatly extend the capability of these agency research platform aircraft. Current projects and plans involve satellite links on the Perseus UAV and the ER-2 via TDRSS and a proposed experiment on the NASA Advanced Communications Technology Satellite. Provisions for data links on the Perseus research platform, via TDRSS S-band multiple access service, have been developed and are being tested. Test flights at Dryden are planned to demonstrate successful end-to-end data transfer. A Unisys Corp. airborne satcom STARLink system is being integrated into an Ames ER-2 aircraft. This equipment will support multiple data rates up to 43 Mb/s each via the TDRS S Ku-band single access service. The first flight mission for this high-rate link is planned for August 1995. Ames and JPL have proposed an ACTS experiment to use real-time satellite communications to improve wildfire research campaigns. Researchers and fire management teams making use of instrumented aircraft platforms at a prescribed burn site will be able to communicate with experts at Ames, the U.S. Forest Service, and emergency response agencies.

  20. Introduction. Aging, Communication and Media Technologies

    Directory of Open Access Journals (Sweden)

    Kim Sawchuk

    2016-06-01

    Full Text Available What does it mean to age within “networked societies” (Castells, 2000? What might be learned if we take the Internet and Communication Technology (ICT and media experiences of older adults into account in our research? These questions are core to this special issue on Aging, Communication and Media Technologies. Comprised of six papers from authors working in five cultural contexts in Europe and North America, Aging, Communication and Media Technologies offers insights into demographic transformations towards ‘ageing societies’ in the industrialized world, changes in the media and technological landscape, and the variegated practices of communication in different cultural contexts.

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

    Science.gov (United States)

    2017-03-01

    product of the Defense Science Board (DSB). The DSB is a Federal Advisory Committee established to provide independent advice to the Secretary of Defense...December 2014, the Under Secretary of Defense for Acquisition, Technology, and Logistics (USD(AT&L)) signed the “Terms of Reference – Defense Science ...Board Task Force on Military Satellite Communication and Tactical Networking.” As a result, the Chairman of the Defense Science Board established a

  2. Electric Propulsion for Low Earth Orbit Communication Satellites

    Science.gov (United States)

    Oleson, Steven R.

    1997-01-01

    Electric propulsion was evaluated for orbit insertion, satellite positioning and de-orbit applications on big (hundreds of kilograms) and little (tens of kilograms) low earth orbit communication satellite constellations. A simple, constant circumferential thrusting method was used. This technique eliminates the complex guidance and control required when shading of the solar arrays must be considered. Power for propulsion was assumed to come from the existing payload power. Since the low masses of these satellites enable multiple spacecraft per launch, the ability to add spacecraft to a given launch was used as a figure of merit. When compared to chemical propulsion ammonia resistojets, ion, Hall, and pulsed plasma thrusters allowed an additional spacecraft per launch Typical orbit insertion and de-orbit times were found to range from a few days to a few months.

  3. Channel Estimation And Multiuser Detection In Asynchronous Satellite Communications

    CERN Document Server

    Chaouech, Helmi; 10.5121/ijwmn.2010.2411

    2010-01-01

    In this paper, we propose a new method of channel estimation for asynchronous additive white Gaussian noise channels in satellite communications. This method is based on signals correlation and multiuser interference cancellation which adopts a successive structure. Propagation delays and signals amplitudes are jointly estimated in order to be used for data detection at the receiver. As, a multiuser detector, a single stage successive interference cancellation (SIC) architecture is analyzed and integrated to the channel estimation technique and the whole system is evaluated. The satellite access method adopted is the direct sequence code division multiple access (DS CDMA) one. To evaluate the channel estimation and the detection technique, we have simulated a satellite uplink with an asynchronous multiuser access.

  4. 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.

  5. 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.

  6. Research in space commercialization, technology transfer, and communications

    Science.gov (United States)

    1982-01-01

    Research and internship programs in technology transfer, space commercialization, and information and communications policy are described. The intern's activities are reviewed. On-campus research involved work on the costs of conventional telephone technology in rural areas, an investigation of the lag between the start of a research and development project and the development of new technology, using NASA patent and patent waiver data, studies of the financial impact and economic prospects of a space operation center, a study of the accuracy of expert forecasts of uncertain quantities and a report on frequency coordination in the fixed and fixed satellite services at 4 and 6 GHz.

  7. EFFECTS OF RAIN ATTENUATION ON SATELLITE COMMUNICATION LINK

    Directory of Open Access Journals (Sweden)

    G. N. Ezeh

    2014-06-01

    Full Text Available Rain attenuation is a major challenge to microwave satellite communication especially at frequencies above 10 GHz, causing unavailability of signals most of the time. Rain attenuation predictions have become one of the vital considerations while setting up a satellite communication link. In this study, rain attenuation models, cumulative distribution curves and other analytical tools for successful prediction of rain attenuation are presented. A three year Rain rate data was obtained from the Nigeria Meteorological Agency (NIMET database in addition to experimental data. Of the three prediction models used in the study, Ajayi model gave the range of values closest to the experimental data. A correctional factor was determined as 1.0988 and used to modify the Ajayi model. This modification to Ajayi’s model enabled its rain attenuation values conform more closely to the experimental result.

  8. 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.

  9. Defense Satellite Communications: DOD Needs Additional Information to Improve Procurements

    Science.gov (United States)

    2015-07-01

    SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT Same as Report (SAR) 18. NUMBER OF PAGES 31 19a. NAME OF RESPONSIBLE PERSON a. REPORT...information available, DOD spent over $1 billion leasing commercial SATCOM. In prior work, GAO found that some major DOD users of commercial...Committee on Armed Services United States Senate The Department of Defense (DOD) leases commercial satellite communications (SATCOM) to support a variety

  10. System analysis for millimeter-wave communication satellites

    Science.gov (United States)

    Holland, L. D.; Hilsen, N. B.; Gallagher, J. J.; Stevens, G.

    1980-01-01

    Research and development needs for millimeter-wave space communication systems are presented. Assumed propagation fade statistics are investigated along with high data rate diversity link and storage. The development of reliable ferrite switches, and high performance receivers and transmitters is discussed, in addition to improved tolerance of dish and lens fabrication for the antennas. The typical cost for using a simplex voice channel via a high capacity 40/50 GHz satellite is presented.

  11. 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.

  12. Status of the Third Miniature Sensor Technology Integration Satellite Mission

    OpenAIRE

    Barnhart, David; Hurtz, Rick; McClelland, Jim; Cellarius, Mark; Meyers, AI

    1994-01-01

    The MSTI-3 satellite is the third in a series established to test, in realistic scenarios, miniature spacecraft and sensor technologies for missile detection and tracking on low-cost, low-earth orbit technology demonstration satellites. Cooperative demonstrations are planned to combine MSTI-provided target track file information, with interceptor technology tests, to fully demonstrate technologies associated with theater missile defense (TMO) targeting. The program is sponsored by the Ballist...

  13. The Impact of Technology on Superintendent Communication

    Science.gov (United States)

    Kelly, Victoria L.

    2009-01-01

    Technological advances have revolutionized the communication patterns and behaviors of district leaders. In this information-based society, the ability of the leader to select the form of communication most appropriate to the context and situation qualifies his or her effectiveness at communication. The findings emerging from this study highlight…

  14. Fiber Optic Communications Technology. A Status Report.

    Science.gov (United States)

    Hull, Joseph A.

    Fiber optic communications (communications over very pure glass transmission channels of diameter comparable to a human hair) is an emerging technology which promises most improvements in communications capacity at reasonable cost. The fiber transmission system offers many desirable characteristics representing improvements over conventional…

  15. Interactive Communication Technologies in Business Organizations.

    Science.gov (United States)

    Rogers, Everett M.; Allbritton, Marcel M.

    1995-01-01

    Explores the distinctive aspects of the new interactive communication technologies (electronic mail over the Internet) in business communication and their implications. Discusses the growth of interactive communication, the concept of interactivity, physical distance and social presence, getting to critical mass, and flexibility and control of…

  16. Trust and New Communication Technologies

    DEFF Research Database (Denmark)

    Ess, Charles

    2010-01-01

    I approach philosophical analyses of the phenomenon of trust vis-à-vis online communication, beginning with an overview from within the framework of computer-mediated communication (CMC) of concerns and paradigmatic failures of trust in the history of online communication. I turn to more directly...

  17. Information and Communications Technology Literacy

    Directory of Open Access Journals (Sweden)

    Syarifuddin Syarifuddin

    2014-12-01

    Full Text Available Development of information and communication technology (ICT has brought changes for the people of Indonesia. With ICT, community can easily access a variety of information and support jobs. But the problem that arises is the uneven penetration of ICT in all parts of Indonesia, including in South Sulawesi. Giving rise to the digital divide as well as the weakness of ICT literacy. Therefore, this study aims to determine the ICT literacy community in South Sulawesi. The method used in this study is a survey with a quantitative approach. The results show that ICT (computer, mobile phone, and internet has been used by communities in South Sulawesi. Among the three media, mobile phone has the highest number of penetration followed by computer and the internet. The majority of respondents have also entered into 5 levels of ICT literacy mobile phones and computers as an integral part of daily activities. While the internet was still in level 3 where they have been used but not significantly.

  18. 78 FR 14952 - Earth Stations Aboard Aircraft Communicating with Fixed-Satellite Service Geostationary-Orbit...

    Science.gov (United States)

    2013-03-08

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 2 Earth Stations Aboard Aircraft Communicating with Fixed-Satellite Service Geostationary-Orbit Space Stations AGENCY: Federal Communications Commission. ACTION: Proposed rule....

  19. Terabit-per-Second Satellite Links: a Path Toward Ubiquitous Terahertz Communication

    Science.gov (United States)

    Suen, Jonathan Y.

    2016-07-01

    Due to the demand for high-speed wireless communications, carrier frequencies have increased in the search for both available and wider bands. The millimeter-wave and terahertz bands (0.1-3 THz) are commonly believed to be impractical for all but short-range links due to severe attenuation by atmospheric water vapor. However, the field of submillimeter radio astronomy has demonstrated that this can be effectively mitigated by the construction of large aperture telescopes in very dry high-altitude locations, such as the Atacama Large Millimeter/submillimeter Array (ALMA) in the Chilean Andes. Modeling has shown that Earth-satellite links in excess of 1 Tb per second can be achieved with a system patterned off observatories, since the loss of a satellite link from a dry location equals a sea-level path of only several kilometers. Despite advantages over optical satellite links, THz links have not been an area of active study. We review the technology and science necessary to develop a terabit-per-second THz satellite link and argue that a satellite link offers a good first step toward the development of ubiquitous THz communications.

  20. Communication Satellite Payload Special Check out Equipment (SCOE) for Satellite Testing

    Science.gov (United States)

    Subhani, Noman

    2016-07-01

    This paper presents Payload Special Check out Equipment (SCOE) for the test and measurement of communication satellite Payload at subsystem and system level. The main emphasis of this paper is to demonstrate the principle test equipment, instruments and the payload test matrix for an automatic test control. Electrical Ground Support Equipment (EGSE)/ Special Check out Equipment (SCOE) requirements, functions and architecture for C-band and Ku-band payloads are presented in details along with their interface with satellite during different phases of satellite testing. It provides test setup, in a single rack cabinet that can easily be moved from payload assembly and integration environment to thermal vacuum chamber all the way to launch site (for pre-launch test and verification).

  1. 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.

  2. Distribution system protection with communication technologies

    DEFF Research Database (Denmark)

    Wei, Mu; Chen, Zhe

    2010-01-01

    Due to the communication technologies’ involvement in the distribution power system, the time-critical protection function may be implemented more accurately, therefore distribution power systems’ stability, reliability and security could be improved. This paper presents an active distribution...... power system, including CHPs (Combined Heating and Power) and small scaled WTs (Wind Turbines), as a practical example to examine the possible impacts of communication technologies on the power system. Under some fault scenarios, the power system’s responses to the fault are compared between the system...... with communication technologies and that without communication technologies. At the same time, the previously proposed study method of combining the simulations of communication and power systems is adopted in this study. The performance of a communication network adopted for power system is simulated by OPNET...

  3. Massive information sharing among global data centers based on satellite laser communication

    Science.gov (United States)

    Yi, Longteng; Li, Cong; Liu, Naijin

    2015-10-01

    With the development of big data and information globalization, the requirements of massive information transmitting and sharing among data centers are expanding, especially among those data centers which are extremely far away from each other. In the above field, conventional optical fiber transmission faces many problems such as complex networking, poor security, long node switching delay, high lease and maintain cost and low migration flexibility. Besides, in the near future, data centers may tend to be built in the remote Polar Regions or on the sea for natural cooling. For the above situation, sharing the massive information among global data centers based on satellite laser communication is proposed in this paper. This proposal includes advantage analysis, research of restraining atmosphere interference, etc. At last, by comparison with conventional technology, the research result shows that massive information transmitting and sharing among global data centers based on satellite laser communication has far reaching application potential.

  4. W频段卫星通信中正交频分复用技术的误码性能分析%Bit error rate analysis of orthogonal frequency division multiplexing technology in W-band satellite communication

    Institute of Scientific and Technical Information of China (English)

    赵乐; 宋爱民; 刘剑; 薛斌; 郭兴阳

    2015-01-01

    针对传统的卫星通信频段( C频段、Ku频段、Ka频段)应用逐渐趋于饱和的问题,研究了更高的W频段卫星通信。该频段带宽更宽,可以支持更高的数据传输速率,同等条件下天线尺寸更小并可获得更大的天线增益。正交频分复用技术具有很高的频带利用率,适合于高速数据传输,在W频段具有很好的应用前景。参照“IKNOW”项目中的链路预算,采用固态功放的Rapp模型,对OFDM技术应用在W频段卫星通信中的误码性能进行了仿真分析。仿真结果表明:在考虑功放非线性时,存在一个最佳的输入功率补偿点,使OFDM系统的误码率最低,并且发射功率越高,最佳补偿点对应的误码率越低。%Since traditional band applications ( C-band, Ku-band, Ka-band) for satellite communication will gradually tend to be saturated, the higher W-band was studied. W-band has a wider bandwidth, supports a higher data rate, acquires a smaller equipment size and a bigger antenna gain under the same conditions. Orthogonal Frequency Division Multiplexing ( OFDM) technology has a high spectrum efficiency, which makes it be suitable for high data rate transmission, so it has a good application prospect in W-band. Referring to the link budget of “IKNOW” project and using the Rapp model of solid-state power amplifier, the Bit Error Rate ( BER) of OFDM in W-band was simulated and analyzed. The simulation results show that there is a best input power backoff point which makes the BER be lowest when the nonlinear power amplifier is taken in account, and the higher the transmission power is, the lower the BER of the best input power backoff point will be.

  5. The Federal Communications Commission and the Communications Satellite Corporation: A Question of Ownership.

    Science.gov (United States)

    Lee, William E.

    When NASA announced in 1960 that private enterprise would produce communication satellites, rather than the Federal government, several large corporations proposed a joint venture involving a group of international carriers and electronic manufacturers, while American Telephone and Telegraph requested sole ownership. At that time, the Federal…

  6. Advanced Communication and Networking Technologies for Mars Exploration

    Science.gov (United States)

    Bhasin, Kul; Hayden, Jeff; Agre, Jonathan R.; Clare, Loren P.; Yan, Tsun-Yee

    2001-01-01

    Next-generation Mars communications networks will provide communications and navigation services to a wide variety of Mars science vehicles including: spacecraft that are arriving at Mars, spacecraft that are entering and descending in the Mars atmosphere, scientific orbiter spacecraft, spacecraft that return Mars samples to Earth, landers, rovers, aerobots, airplanes, and sensing pods. In the current architecture plans, the communication services will be provided using capabilities deployed on the science vehicles as well as dedicated communication satellites that will together make up the Mars network. This network will evolve as additional vehicles arrive, depart or end their useful missions. Cost savings and increased reliability will result from the ability to share communication services between missions. This paper discusses the basic architecture that is needed to support the Mars Communications Network part of NASA's Space Science Enterprise (SSE) communications architecture. The network may use various networking technologies such as those employed in the terrestrial Internet, as well as special purpose deep-space protocols to move data and commands autonomously between vehicles, at disparate Mars vicinity sites (on the surface or in near-Mars space) and between Mars vehicles and earthbound users. The architecture of the spacecraft on-board local communications is being reconsidered in light of these new networking requirements. The trend towards increasingly autonomous operation of the spacecraft is aimed at reducing the dependence on resource scheduling provided by Earth-based operators and increasing system fault tolerance. However, these benefits will result in increased communication and software development requirements. As a result, the envisioned Mars communications infrastructure requires both hardware and protocol technology advancements. This paper will describe a number of the critical technology needs and some of the ongoing research

  7. 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.

  8. Novel Ku Band Reflectarray Antenna for Satellite Communication

    Directory of Open Access Journals (Sweden)

    Sridhar Bilvam

    2014-04-01

    Full Text Available This study focuses on the design and analysis of Ku band reflectarray antenna using a novel crossed dumbbell (clover patch unit cell. The reflectarray is proposed for application in satellite communication more specifically for Satellite newsgathering (12.5-13.75 GHz. The clover shaped unit cell is designed for 13.07 GHz and the suitability of the unit cell is validated using the phase characteristics analysis. The effect of the elements on the performance represented by the range of the reflection phase is of prime importance. From the observation, Clover unit cell has large phase variation compared to minkowski and koch unit cells. Therefore, the main purpose of this study is to investigate and validate the novel unit cell with a wide phase characteristics and the reflectarray constructed.

  9. Chaos Based Secure IP Communications over Satellite DVB

    Science.gov (United States)

    Caragata, Daniel; El Assad, Safwan; Tutanescu, Ion; Sofron, Emil

    2010-06-01

    The Digital Video Broadcasting—Satellite (DVB-S) standard was originally conceived for TV and radio broadcasting. Later, it became possible to send IP packets using encapsulation methods such as Multi Protocol Encapsulation, MPE, or Unidirectional Lightweight Encapsulation, ULE. This paper proposes a chaos based security system for IP communications over DVB-S with ULE encapsulation. The proposed security system satisfies all the security requirements while respecting the characteristics of satellite links, such as the importance of efficient bandwidth utilization and high latency time. It uses chaotic functions to generate the keys and to encrypt the data. The key management is realized using a multi-layer architecture. A theoretical analysis of the system and a simulation of FTP and HTTP traffic are presented and discussed to show the cost of the security enhancement and to provide the necessary tools for security parameters setup.

  10. Two way satellite communication for telemetrology and remote control

    Science.gov (United States)

    Hanebrekke, H.

    Low-data-rate satellite communication to fixed and floating buoys at sea, remote observation stations, and fishing vessels is studied. Particular attention is paid to Norwegian conditions, that is, high latitude and high mountains. Coverage and reliability measurements utilizing Inmarsat C and Prodat stations have been done along the coast of western and northern Norway, and on major roads in southern Norway. Good coverage is found in the coastal areas, with only 5 percent loss of messages when both the AOR and IOR satellites are used from the same location, whereas the land mobile experiments gave 40 percent to 70 percent loss, depending on the elevation angle. The possibility of using Inmarsat C or Prodat stations in the major fishing areas between Norway, Greenland, and Svalbard and in the Barents Sea are also being investigated. A method of data collection from ocean areas based on the fishing fleet is proposed.

  11. Strengthening 4-H Program Communication through Technology

    Science.gov (United States)

    Robideau, Kari; Santl, Karyn

    2011-01-01

    Advances in technology are transforming how youth and parents interact with programs. The Strengthening 4-H Communication through Technology project was implemented in eight county 4-H programs in Northwest Minnesota. This article outlines the intentional process used to effectively implement technology in program planning. The project includes:…

  12. Research on the Status Quo of Satellite Optical Communication%卫星光通信的现状研究

    Institute of Scientific and Technical Information of China (English)

    吕岳海

    2015-01-01

    在空间卫星通信中,激光通信技术是一种能够传输大容量数据的计术。文章整理了一些卫星光通信的实验数据。特别是日本宇宙航空研究开发机构(JAXA)的光学轨道间通信工程试验卫星(OICETS)与日本国家信息通信技术研究所(NICT)光学地面站之间的低轨道双向光学通信试验。试验成功的证明了在大气环境影响下激光通信的可行性。%In satellite communications, laser communication technology is a transmission of large capacity data technology. Experimental data of some satellite optical communication are organized in this paper. In particular, the Japan Aerospace Exploration Agency (JAXA) optical inter orbit communications engineering test satellite (oicets) and Japanese national information and communication technology of the (NICT) optical ground station between low earth orbit bi-directional optical communication test. The feasibility of laser communication in atmosphere is proved successfully.

  13. Cultures in orbit: Satellite technologies, global media and local practice

    Science.gov (United States)

    Parks, Lisa Ann

    Since the launch of Sputnik in 1957, satellite technologies have had a profound impact upon cultures around the world. "Cultures in Orbit" examines these seemingly disembodied, distant relay machines in relation to situated social and cultural processes on earth. Drawing upon a range of materials including NASA and UNESCO documents, international satellite television broadcasts, satellite 'development' projects, documentary and science fiction films, remote sensing images, broadcast news footage, World Wide Web sites, and popular press articles I delineate and analyze a series of satellite mediascapes. "Cultures in Orbit" analyzes uses of satellites for live television relay, surveillance, archaeology and astronomy. The project examines such satellite media as the first live global satellite television program Our World, Elvis' Aloha from Hawaii concert, Aboriginal Australian satellite programs, and Star TV's Asian music videos. In addition, the project explores reconnaissance images of mass graves in Bosnia, archaeological satellite maps of Cleopatra's underwater palace in Egypt, and Hubble Space Telescope images. These case studies are linked by a theoretical discussion of the satellite's involvement in shifting definitions of time, space, vision, knowledge and history. The satellite fosters an aesthetic of global realism predicated on instantaneous transnational connections. It reorders linear chronologies by revealing traces of the ancient past on the earth's surface and by searching in deep space for the "edge of time." On earth, the satellite is used to modernize and develop "primitive" societies. Satellites have produced new electronic spaces of international exchange, but they also generate strategic maps that advance Western political and cultural hegemony. By technologizing human vision, the satellite also extends the epistemologies of the visible, the historical and the real. It allows us to see artifacts and activities on earth from new vantage points

  14. Development of a web-based picture archiving and communication system using satellite data communication.

    Science.gov (United States)

    Hwang, S; Lee, J; Kim, H; Lee, M

    2000-01-01

    Using the JAVA language we have developed a Web-based picture archiving and communication system (PACS) which allows a remote hospital to access medical images. An asymmetric satellite data communication system (ASDCS) provided a receive-only link for data delivery and a conventional terrestrial link (which could be the conventional telephone network) allowed data transmission. The satellite communication link was 10-30 times faster than the conventional terrestrial link. To increase image transmission speeds over the Internet connection, JPEG and wavelet compression methods were used. The resulting images were evaluated quantitatively by measuring the peak signal:noise ratio and qualitatively by radiologists. Compression ratios of 10:1 or less were deemed acceptable for diagnostic purposes. The system appears to be suitable for teleradiology and telemedicine.

  15. 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.

  16. 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.

  17. STRUCTURE OF THE SPANISH SYSTEM OF SATELLITE OF COMMUNICATIONS

    Directory of Open Access Journals (Sweden)

    F. Sacristán - Romero

    2007-04-01

    Full Text Available The objectives of satellites HISPASAT are oriented towards the search to satisfy necessities derived from the transport of television and radio signals. It tries the supplying of a basic and safe support of communications for the defence and security of the national territory, the creation of an infrastructure of channels for official networks, routes of data, restoration of connections, rural telephony. Also is wanted to foment the provision of television channels for the Hispanic community in the south and center of America and the broadcasting of services of television for people in general.

  18. Coordination procedure for radio relay and communication satellite services

    Science.gov (United States)

    Eckerman, J.

    1973-01-01

    A global rain rate statistic model is used to link microwave propagation statistics to measurable rain statistics in order to develop international telecommunication site criteria for radio relay and communication satellite services that minimize interference between receivers and transmitters. This rain coordination procedure utilizes a rain storm cell size, a statistical description of the rainfall rate within the cell valid for most of the earth's surface, approximations between Raleigh scatter and constancy of precipitation with altitude, and an analytic relation between radar reflectivity and rain rate.

  19. Computing, Information and Communications Technology (CICT) Website

    Science.gov (United States)

    Hardman, John; Tu, Eugene (Technical Monitor)

    2002-01-01

    The Computing, Information and Communications Technology Program (CICT) was established in 2001 to ensure NASA's Continuing leadership in emerging technologies. It is a coordinated, Agency-wide effort to develop and deploy key enabling technologies for a broad range of mission-critical tasks. The NASA CICT program is designed to address Agency-specific computing, information, and communications technology requirements beyond the projected capabilities of commercially available solutions. The areas of technical focus have been chosen for their impact on NASA's missions, their national importance, and the technical challenge they provide to the Program. In order to meet its objectives, the CICT Program is organized into the following four technology focused projects: 1) Computing, Networking and Information Systems (CNIS); 2) Intelligent Systems (IS); 3) Space Communications (SC); 4) Information Technology Strategic Research (ITSR).

  20. SATELLITE GRAVITY SURVEYING TECHNOLOGY AND RESEARCH OF EARTH'S GRAVITY FIELD

    Institute of Scientific and Technical Information of China (English)

    Ning Jinsheng

    2003-01-01

    This is a summarized paper. Two topics are discussed: Firstly, the concept, development and application of four kinds of satellite gravity surveying technology are introduced; Secondly, some problems of theory and method, which must be considered in the study of the Earth's gravity field based on satellite gravity data, are expounded.

  1. Wireless communication technologies in distribution automation

    Energy Technology Data Exchange (ETDEWEB)

    Takala, J. [VTT Energy, Espoo (Finland)

    1998-08-01

    The project started in mid 1995 and will be finished in 1997. The project examines four different wireless communication technologies: GSM short message service, NMT data calls, packet radio network and Autonet (Actionet) status message service. The targets for communication include: Energy measurement, especially in the de-regulated electricity market, secondary sub-station control and fault indicators. The research has been focused on the usability of different communication technologies for different purposes. Data about response times, reliability, error rates, retry times, communication delays, costs etc. has been collected about each communication technology and comparative results were analysed. Some field experiments and demonstrations will be made in energy measurement and distribution network remote control. The project is divided into four tasks. Each task is described briefly

  2. High-speed analog fiber optic links for satellite communication

    Science.gov (United States)

    Daryoush, A. S.; Herczfeld, P. R.; Kunath, R. R.

    1988-01-01

    Large-aperture phased array antennas operating at millimeter wave frequencies are designed for space-based communications and imaging. Array elements are comprised of active transmit/receive (T/R) modules which are linked to the central processing unit through a high-speed fiberoptic network. This paper demonstrates optical control of active modules for satellite communication at 24 GHz. An approach called T/R level data mixing, which utilizes fiberoptic transmission of a data signal to individual T/R modules to be upconverted by an optically synchronized local oscillator, is demonstrated at 24 GHz. A free-running HEMT oscillator, used as local oscillator at 24 GHz, is synchronized using indirect subharmonic optical injection locking over a locking range of 14 MHz. Results of data link performance over 500-1000 MHz is also reported in terms of gain-bandwidth, linearity and third-order intercept, sensitivity, and dynamic range.

  3. Improving MILSATCOM (Military Satellite Communication) acquisition outcomes: Lease versus buy

    Science.gov (United States)

    Dinneen, P. M.; Quinn, T. H.

    1985-01-01

    This study was requested by the Director of Space Systems and Command, Control, and Communications, Office of the Deputy Chief of Staff (Research, Development, and Acquisition), Headquarters United States Air Force, to assist in improving the outcomes of military satellite communication (MILSATCOM) programs. In view of rapidly rising costs of military space systems, leasing has been suggested as one way of controlling these costs. The purpose of this study, therefore, was to identify and analyze the central considerations relevant to determining whether to lease or by MILSATCOM services. The results of this report should be of interest to members of MILSATCOM acquisition community and others concerned with making lease versus buy decisions in the public sector. The work was conducted under the MILSATCOM Acquisition Policy project of the Project Air Force Resource Management Program.

  4. Relevance of integrating Information Communication Technology ...

    African Journals Online (AJOL)

    ... Communication Technology (ICT) into programmes of teacher formation in Nigerian ... The paper defined ICT in pedagogical context and so established its ... tool need to be reduced significantly or eliminated for effective teacher formation.

  5. India's Perspective of Information and Communication Technologies ...

    African Journals Online (AJOL)

    India's Perspective of Information and Communication Technologies (ICTs) for ... Information is a vital resource for the national development and ensuring ... manner and the role of ICT in the rapid growth of economic transactions over the past ...

  6. Effect of Information Communications Technology on Cataloguing ...

    African Journals Online (AJOL)

    Effect of Information Communications Technology on Cataloguing and ... Data was collected through the use of questionnaire designed for the study. ... at anytime and from any terminal and expect the computer to react and reply immediately.

  7. Information And Communication Technology Literacy Among ...

    African Journals Online (AJOL)

    Information And Communication Technology Literacy Among Academics In Ahmadu Bello ... horizon in education in USA was adopted as data collection instruments. ... The research discovered that computer system, CD-Rom, flash drives, ...

  8. Effect of Information Communication Technology Facilities on ...

    African Journals Online (AJOL)

    Effect of Information Communication Technology Facilities on Students' Performance: ... Results indicated a significant difference in performance in both tests between ... ICT facilities in all secondary schools to enhance teaching and learning.

  9. Information communication Technology (ICT) compliance among ...

    African Journals Online (AJOL)

    Information communication Technology (ICT) compliance among ... The one with very strong effect is the high cost of hardware and software including fear of virus ... requisite education and upgrade themselves through training programme to ...

  10. 122 Factors Influencing Information and Communication Technology ...

    African Journals Online (AJOL)

    Yemi Olojede

    Information and communication technology (ICT) is a veritable tool for ... Respondents' major challenges in accessing ICT were time (x̅ =3.27), Network error .... Furthermore, data collected to address Objective 4 was analyzed with logit.

  11. Development of the sandra antenna for airborne satellite communication

    NARCIS (Netherlands)

    Verpoorte, J.; Schippers, H.; Jorna, P.; Hulzinga, A.; Roeloffzen, C.G.H.; Marpaung, D.A.I.; Sanadgol, B.; Baggen, R.; Wang, Qin; Noharet, B.; Beeker, W.; Leinse, A.; Heideman, R.G.

    2011-01-01

    Novel avionics communication systems are required for increasing flight safety and operational integrity, for optimizing economy of operations and for enhancing passenger services. One of the key technologies to be developed is an antenna system that will provide broadband connectivity within aircra

  12. Enabling Technology for Small Satellite Launch Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Access to space for Small Satellites is enabled by the use of excess launch capacity on existing launch vehicles. A range of sizes, form factors and masses of small...

  13. Enabling Technology for Small Satellite Launch Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Access to space for Small Satellites is enabled by the use of excess launch capacity on existing launch vehicles. A range of sizes, form factors and masses need to...

  14. (CICT) Computing, Information, and Communications Technology Overview

    Science.gov (United States)

    VanDalsem, William R.

    2003-01-01

    The goal of the Computing, Information, and Communications Technology (CICT) program is to enable NASA's Scientific Research, Space Exploration, and Aerospace Technology Missions with greater mission assurance, for less cost, with increased science return through the development and use of advanced computing, information and communications technologies. This viewgraph presentation includes diagrams of how the political guidance behind CICT is structured. The presentation profiles each part of the NASA Mission in detail, and relates the Mission to the activities of CICT. CICT's Integrated Capability Goal is illustrated, and hypothetical missions which could be enabled by CICT are profiled. CICT technology development is profiled.

  15. Networked Operations of Hybrid Radio Optical Communications Satellites

    Science.gov (United States)

    Hylton, Alan; Raible, Daniel

    2014-01-01

    In order to address the increasing communications needs of modern equipment in space, and to address the increasing number of objects in space, NASA is demonstrating the potential capability of optical communications for both deep space and near-Earth applications. The Integrated Radio Optical Communications (iROC) is a hybrid communications system that capitalizes on the best of both the optical and RF domains while using each technology to compensate for the other's shortcomings. Specifically, the data rates of the optical links can be higher than their RF counterparts, whereas the RF links have greater link availability. The focus of this paper is twofold: to consider the operations of one or more iROC nodes from a networking point of view, and to suggest specific areas of research to further the field. We consider the utility of Disruption Tolerant Networking (DTN) and the Virtual Mission Operation Center (VMOC) model.

  16. Communicating in English for Science and Technology

    DEFF Research Database (Denmark)

    Mousten, Birthe

    Communicating in English for Science and Technology covers some of the most important questions in connection with communication models, stylistics and genre conventions within the area of English used in science and technology texts. Moreover,knowledge management, terminology management and data...... and database management principles are included as a means to create consistent writing. Other means of help, such as manuals of style and the adoption of a language policy in corporate life, are included, too....

  17. Power Allocation Algorithm for IDMA-based Multi-Beam Satellite Communication Systems

    Directory of Open Access Journals (Sweden)

    Gongliang Liu

    2012-08-01

    Full Text Available Rain attenuation is one of the most dominant impairment factors that degrade the performance of satellite communications at Ka band and above. In order to solve the technical bottlenecks in the existing Ka-band satellite communication schemes, the authors has introduced the emerging Interleave Division Multiple Access (IDMA technology into multi-beam satellite communication systems, and consequently, a novel power allocation algorithm is proposed for the emerging and promising system in this paper. The main goal of the proposed scheme is to provide sufficient transmission quality to as many mobiles as possible, even for the users suffering heavy rain attenuation. Analysis and simulation results show that compared to the traditional power allocation schemes, the proposed scheme can guarantee high power efficiency even in heavy rain attenuation conditions, illustrating the high efficiency of the Chip-by-Chip (CBC Multi-user Detection (MUD technique in IDMA. Furthermore, in virtue of the Signal to Interference plus Noise Ratio (SINR evolution technique, the proposed scheme can make accurate estimation of available resource on considering the effect of MUD, leading to low outage probability.

  18. Building Technological Capability within Satellite Programs in Developing Countries

    Science.gov (United States)

    Wood, Danielle Renee

    Global participation in space activity is growing as satellite technology matures and spreads. Countries in Africa, Asia and Latin America are creating or reinvigorating national satellite programs. These countries are building local capability in space through technological learning. They sometimes pursue this via collaborative satellite development projects with foreign firms that provide training. This phenomenon of collaborative satellite development projects is poorly understood by researchers of technological learning and technology transfer. The approach has potential to facilitate learning, but there are also challenges due to misaligned incentives and the tacit nature of the technology. Perspectives from literature on Technological Learning, Technology Transfer, Complex Product Systems and Product Delivery provide useful but incomplete insight for decision makers in such projects. This work seeks a deeper understanding of capability building through collaborative technology projects by conceiving of the projects as complex, socio-technical systems with architectures. The architecture of a system is the assignment of form to execute a function along a series of dimensions. The research questions explore the architecture of collaborative satellite projects, the nature of capability building during such projects, and the relationship between architecture and capability building. The research design uses inductive, exploratory case studies to investigate six collaborative satellite development projects. Data collection harnesses international field work driven by interviews, observation, and documents. The data analysis develops structured narratives, architectural comparison and capability building assessment. The architectural comparison reveals substantial variation in project implementation, especially in the areas of project initiation, technical specifications of the satellite, training approaches and the supplier selection process. The individual

  19. Transfer of satellite applications and technology - The need for a U.S. initiative

    Science.gov (United States)

    Hudson, Heather E.

    In the brief history of satellite communications, the United States has passed through three major eras: the Era of Conjecture, the Era of Experiments and the Era of Services. NASA took the lead in the experimental era to demonstrate both technology and applications - and to ensure their transfer for commercial use. The developing world has also entered the Era of Services, but without the benefit of an experimental phase. Several developing countries now have their own domestic systems; others share regqional systems or lease domestic capacity from INTELSAT. However, the record of developmental applications of these satellites has been disappointing to date. Much capacity sits idle. The U.S. has a great deal to share with the developing world to assist in the effective utilization of this technology. A U.S. Satellite Applications and Technology Transfer (SATT) program is proposed.

  20. 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.

  1. Effective communication : satellite system poised to improve information flow

    Energy Technology Data Exchange (ETDEWEB)

    Macedo, R.

    2009-01-15

    This paper described a new satellite technology that can be used to transfer important information from offshore oil and gas facilities to decision-makers in distant onshore offices. Cascade Data Services (CDS), a subsidiary of British Columbia-based MDA Corporation, is developing a high-speed low-latency satellite information transfer service which has its roots in the Cascade Smallsat and Ionospheric Polar Explorer (CASSIOPE) mission scheduled for launch in 2009. The technology will enable customers to move thousands of gigabytes to and from anywhere on the planet on a daily basis. CASSIOPE received funding from the Canadian Space Agency and Technology Partnerships Canada. The first payload will be a suite of space science instruments known as the Enhanced Polar Outflow Probe (e-Pop) developed by researchers at the University of Calgary. The second payload will involve a demonstration of the digital courier service model and delivery of large digital data files. CDS has entered into an alliance with O3b Networks funded by Google Inc., Liberty Global Inc., and HSBC Principal Investments, among others. The technological development should improve the flow of information, making oil and gas operations in remote areas more efficient and help cut costs. 1 ref., 2 figs.

  2. Amateur Radio Communication Technology Contingency Communication in Emergency Situation

    Directory of Open Access Journals (Sweden)

    Johar Azlee

    2017-01-01

    Full Text Available Disasters cannot be avoided, but efforts can be made to reduce death, injuries and property damages through better communications and better planning to deal with it before it happen. Thus we need to adopt available technology, like the Amateur Radio Communication Technology (ACT, to face this problem. These include providing awareness, training and support for the communities who adopt the technology for Emergency Communication (EC. Through having more qualified Amateur Radio Communities (ARC in the adoption of the ARCT, we would be able to improve the communication before, during and after the disasters struck. There are many challenges and issues in the adoption of the ARCT that would part of this study. This article also describes several case studies of communication failure during Hurricane Katrina (2005 in the USA, as well as disasters in several other countries and Malaysia. The tragedies led to failure of existing communication infrastructure, and were reprieved by the help of the voluntary ARC to support the relief agencies in the evacuation and assistance the disaster victims. Therefore, this article will highlight the significant issues that influence the adoption of ARCT in EC.

  3. Test results of the optical PAT test bed for satellite laser communications

    Science.gov (United States)

    Sun, Jianfeng; Liu, Liren; Zhou, Yu; Liu, De'an

    2008-08-01

    Satellite laser communication systems offer many advantages such as high data rate, small sized equipment, low consumption electric power and others. Recent successful demonstrations of laser communications have demonstrated the feasibility of some of the key aspects of this technology. Sub-microradian pointing, acquisition, and tracking (PAT) functions are key issue to establish the laser communication system in space. The terminals must perform a series of onground test to evaluate characteristics of The PAT performances before flight test. So an optical dynamical PAT test bed is developed to perform ground test of a laser terminal. In this paper, we detail the separate test and the system test results of the optical dynamical PAT test bed. The test was carried out by auto-collimation method, the precision deflect accuracy, scan accuracy and deflect scan accuracy are obtained.

  4. Satellite-based technology, systems testing of fishing vessels: Newfoundland Region (1997) = Essais de systèmes de satellites pour les bateaux de pêche : règion de Terre-Neuve (1997)

    National Research Council Canada - National Science Library

    1998-01-01

    The application of satellite-based technology for monitoring fishing vessels and fishing activity is an effective management tool, permitting two-way communication and electronic tracking and reporting...

  5. Advanced Power Technology Development Activities for Small Satellite Applications

    Science.gov (United States)

    Piszczor, Michael F.; Landis, Geoffrey A.; Miller, Thomas B.; Taylor, Linda M.; Hernandez-Lugo, Dionne; Raffaelle, Ryne; Landi, Brian; Hubbard, Seth; Schauerman, Christopher; Ganter, Mathew; hide

    2017-01-01

    NASA Glenn Research Center (GRC) has a long history related to the development of advanced power technology for space applications. This expertise covers the breadth of energy generation (photovoltaics, thermal energy conversion, etc.), energy storage (batteries, fuel cell technology, etc.), power management and distribution, and power systems architecture and analysis. Such advanced technology is now being developed for small satellite and cubesat applications and could have a significant impact on the longevity and capabilities of these missions. A presentation during the Pre-Conference Workshop will focus on various advanced power technologies being developed and demonstrated by NASA, and their possible application within the small satellite community.

  6. CONTACT: An Air Force technical report on military satellite control technology

    Science.gov (United States)

    Weakley, Christopher K.

    1993-07-01

    This technical report focuses on Military Satellite Control Technologies and their application to the Air Force Satellite Control Network (AFSCN). This report is a compilation of articles that provide an overview of the AFSCN and the Advanced Technology Program, and discusses relevant technical issues and developments applicable to the AFSCN. Among the topics covered are articles on Future Technology Projections; Future AFSCN Topologies; Modeling of the AFSCN; Wide Area Communications Technology Evolution; Automating AFSCN Resource Scheduling; Health & Status Monitoring at Remote Tracking Stations; Software Metrics and Tools for Measuring AFSCN Software Performance; Human-Computer Interface Working Group; Trusted Systems Workshop; and the University Technical Interaction Program. In addition, Key Technology Area points of contact are listed in the report.

  7. Alternative packet switch architectures for a 30/20 GHz FDMA/TDMA geostationary communication satellite network

    Science.gov (United States)

    Stehle, Roy; Ogier, Richard G.

    1995-01-01

    This study has investigated alternatives for realizing a packet-based network switch for deployment on a communication satellite. The emphasis was on the avoidance of contention problems that can occur due to the simultaneous arrival of an excessive number of packets destined for the same downlink dwell. The study was to look ahead, beyond the current Advanced Communications Technology Satellite (ACTS) capability, to the next generation of satellites. The study has not been limited by currently available technology, but has used university and commercial research efforts as a basis for designs that can be readily constructed and launched within the next five years. Tradeoffs in memory requirement, power requirement, and architecture have been considered as a part of our study.

  8. INFORMATION TECHNOLOGY AND COMMUNICATION IN NURSING EDUCATION

    Directory of Open Access Journals (Sweden)

    C. R. B. Costa

    2014-07-01

    Full Text Available The use of information and communication technologies in education, transforms not only the way we communicate, but also work, decide and think, as well as allows you to create rich, complex and diversified learning situations, through sharing the tasks between teachers and students , providing an interactive, continuous and lifelong learning. The paper aims to reflect on the importance of the use of information and communication technologies in higher education and show the potential in promoting changes and challenges for teachers of undergraduate nursing course. This is a literary review concerning the issue at hand, in the period from February to March 2014. The result indicates that the resources of information and communication technologies are strategies for the education of future nurses and promote the changing process for teachers , providing quality education to students and understanding that we must seek new opportunities to build a new style of training.

  9. White LED visible light communication technology research

    Science.gov (United States)

    Yang, Chao

    2017-03-01

    Visible light communication is a new type of wireless optical communication technology. White LED to the success of development, the LED lighting technology is facing a new revolution. Because the LED has high sensitivity, modulation, the advantages of good performance, large transmission power, can make it in light transmission light signal at the same time. Use white LED light-emitting characteristics, on the modulation signals to the visible light transmission, can constitute a LED visible light communication system. We built a small visible optical communication system. The system composition and structure has certain value in the field of practical application, and we also research the key technology of transmitters and receivers, the key problem has been resolved. By studying on the optical and LED the characteristics of a high speed modulation driving circuit and a high sensitive receiving circuit was designed. And information transmission through the single chip microcomputer test, a preliminary verification has realized the data transmission function.

  10. Optical wireless communications an emerging technology

    CERN Document Server

    Capsoni, Carlo; Ghassemlooy, Zabih; Boucouvalas, Anthony; Udvary, Eszter

    2016-01-01

    This book focuses on optical wireless communications (OWC), an emerging technology with huge potential for the provision of pervasive and reliable next-generation communications networks. It shows how the development of novel and efficient wireless technologies can contribute to a range of transmission links essential for the heterogeneous networks of the future to support various communications services and traffic patterns with ever-increasing demands for higher data-transfer rates. The book starts with a chapter reviewing the OWC field, which explains different sub-technologies (visible-light, ultraviolet (UV) and infrared (IR) communications) and introduces the spectrum of application areas (indoor, vehicular, terrestrial, underwater, intersatellite, deep space, etc.). This provides readers with the necessary background information to understand the specialist material in the main body of the book, which is in four parts. The first of these deals with propagation modelling and channel characterization of ...

  11. A statistical rain attenuation prediction model with application to the advanced communication technology satellite project. Part 2: Theoretical development of a dynamic model and application to rain fade durations and tolerable control delays for fade countermeasures

    Science.gov (United States)

    Manning, Robert M.

    1987-01-01

    A dynamic rain attenuation prediction model is developed for use in obtaining the temporal characteristics, on time scales of minutes or hours, of satellite communication link availability. Analagous to the associated static rain attenuation model, which yields yearly attenuation predictions, this dynamic model is applicable at any location in the world that is characterized by the static rain attenuation statistics peculiar to the geometry of the satellite link and the rain statistics of the location. Such statistics are calculated by employing the formalism of Part I of this report. In fact, the dynamic model presented here is an extension of the static model and reduces to the static model in the appropriate limit. By assuming that rain attenuation is dynamically described by a first-order stochastic differential equation in time and that this random attenuation process is a Markov process, an expression for the associated transition probability is obtained by solving the related forward Kolmogorov equation. This transition probability is then used to obtain such temporal rain attenuation statistics as attenuation durations and allowable attenuation margins versus control system delay.

  12. Research on Receiving Technology Based on Blind Signal Separation for Satellite MIMO Communication System%基于盲分离的卫星MIMO系统接收技术研究

    Institute of Scientific and Technical Information of China (English)

    辛吉荣; 万坚; 陈绍贺; 程建

    2013-01-01

    针对卫星MIMO(Multi-Input Multi-Output)通信系统,提出采用盲分离的思路对各卫星信号进行接收.考虑到盲分离性能易受噪声、混合矩阵病态性的影响,分析了噪声对接收性能影响最小时信道传输矩阵(即盲分离中的混合矩阵)应满足的条件,并给出了满足此条件的等距线阵的构建方式.通过计算机仿真分析了在此方式下,等距线阵的方位角、间距以及信号频率对盲分离接收的影响,最后得出对天线阵列建设具有一定指导意义的结论,为进一步进行实验奠定基础.%Methods of using blind signal processing was proposed to receive the communication signal in Satellite MIMO (Multi-Input Multi-Output) system. Since the receiving performance was affected by noise and illness of mixing matrix, the channel transfer matrix (also called mixing matrix in blind signal processing) that minimized the noise affection was analyzed. The relationship between the transfer matrix and the uniform linear array's parameter such as azimuth angle, distance between two adjacent antennas and the frequency was also analyzed by simulation. Final, some conclusions useful in designing an antenna array in satellite communication system were given out.

  13. Communication Technologies Preferred by School Based Administrators

    Science.gov (United States)

    Weir, Paul

    2012-01-01

    The purpose of this study was to determine the communication technologies preferred by school based administrators. This study surveyed and interviewed 96 school based administrators in a mid-sized suburban school system. The data show that individual emails, email lists, and cell phone technologies had the highest percentage effectiveness ratings…

  14. Adoption of communication technologies and national culture

    NARCIS (Netherlands)

    Hofstede, G.J.

    2001-01-01

    This paper investigates the question what attributes of countries influence the differential speed at which they adopt new communication technologies. On the basis of empirical data, it concludes that besides GNP per capita, cultural variables predict the speed of technology adoption. In particular,

  15. WDM in Courses of Communication Technologies

    Directory of Open Access Journals (Sweden)

    Miloslav Filka

    2008-01-01

    Full Text Available This conference paper shows and demonstrates how modern technologies (such as WDM – Wavelength Division Multiplex were introduced to students of Optical Networks lectured at Brno University of Technology, Faculty of Electrical Engineering and Communication, Dept. of Telecommunications.

  16. Blogging in the Communication Technology Course

    Science.gov (United States)

    Platt, Carrie Anne

    2011-01-01

    This article describes an assignment that was developed for an undergraduate course on communication technologies taught at a public university in the Upper Midwest. The course focuses on the impact of new media technologies on traditional media industries and contemporary culture, and is taken by students majoring in journalism, public relations,…

  17. Information and Communication Technology Inside Out

    DEFF Research Database (Denmark)

    Riis, Søren

    2017-01-01

    Information and communication technology (ICT) has become the great technological fix of our time and not the least in the education system. There seems to be no end to the hype of ICT and the accompanying promises that education will be revolutionized—“smart” pupils will be made and the so...

  18. Information and Communication Technology as a Driver for Change in Agri-food Chains

    NARCIS (Netherlands)

    Poppe, Krijn J.; Wolfert, J.; Verdouw, Cor; Verwaart, Tim

    2013-01-01

    Agri-food chains will be changed in the coming years by Information and Communication Technology (ICT). Technological trends and economic analysis suggest that ICT will be a major driver for innovation. Satellites and sensors make precision agriculture possible. More and more data are being generate

  19. Communicating Customer Value Based on Modern Technologies

    Directory of Open Access Journals (Sweden)

    Slawomir Czarniewski

    2014-06-01

    Full Text Available The article presents the idea of gaining a position of competitive advantage by companies operating in the knowledge-based economy and in the age of modern technology. The rate of change in companies’ environments forces organizations to react quickly to clients’ needs. In recent years, there has been an observed systematic increase in the importance of communicating customer value in Poland. This paper shows changes (trends in the system of market communication in the age of modern technology and changes in the economy. The author presents the mechanisms and effects of communication in age new technology in Poland. Modern technologies enable the collection, storage and transmission of information. Reflections contained in the paper do not have definite characteristics and should be treated as an opinion in the discussion.

  20. Communication technologies in the study environment

    DEFF Research Database (Denmark)

    Thorhauge, Anne Mette

    2012-01-01

    technologies are integrated into organisational structures and practices on campus. This involves a comparison between course management systems on the one hand and students’ personal media (mobile phones, e-mails) on the other hand, with regard to how these are used on campus. On the basis of this analysis, I......In this article, I will analyse and discuss two qualitative case studies concerning ICT in the study environment at the University of Copenhagen, Denmark. I will place special focus on the way in which organisational perspectives as well as technological affordances shape how communication...... will argue that the ways in which these technologies are used reflects two different perspectives on the interplay between communication technology and organisational structure: organisational structure as an anticipation of communication patterns implied in course management system’s design...

  1. FQPSK techniques for satellite and mobile radio communications systems

    Science.gov (United States)

    Li, Yazhuo; Tang, Jing; Tao, Xiaofeng

    2005-11-01

    A continuous phase modulation (CPM) and constant envelope modulation (CEM) alternative of Feher-Patented quadrature phase-shift keying (FQPSK) modulation technique is presented. It is found to provide good spectral efficiencies, power efficiencies, and bit error rate (BER) performance. The modulation schemes of FQPSK are described. The spectral efficiencies, BER performance are also compared with FQPSK and other modulation techniques which are widely used in current mobile and cordless radio standards. The results show that FQPSK modulated signal exhibits much less spectrum spreading than QPSK, OQPSK, and MSK, and the error probability performance of the FQPSK is superior to those in narrow-band nonlinear channels. Based on that, the system capacity and power dissipation are also analyzed for communication systems. It is found that the encoder or receiver for the FQPSK signal to be fully compatible with original I/Q modulated one. FQPSK technique is suitable for nonlinear channels, such as satellite and mobile communications systems reducing the AM/AM and AM/PM adverse effects. At last it is also attempted to extend the application in 3G (CDMA) and 4G (OFDM) mobile communications systems.

  2. 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

  3. Spacetime effects on satellite-based quantum communications

    Science.gov (United States)

    Bruschi, David Edward; Ralph, Timothy C.; Fuentes, Ivette; Jennewein, Thomas; Razavi, Mohsen

    2014-08-01

    We investigate the consequences of space-time being curved on space-based quantum communication protocols. We analyze tasks that require either the exchange of single photons in a certain entanglement distribution protocol or beams of light in a continuous-variable quantum key distribution scheme. We find that gravity affects the propagation of photons, therefore adding additional noise to the channel for the transmission of information. The effects could be measured with current technology.

  4. Spacetime effects on satellite-based quantum communications

    CERN Document Server

    Bruschi, David Edward; Fuentes, Ivette; Jennewein, Thomas; Razavi, Mohsen

    2013-01-01

    We investigate the effects of space-time curvature on space-based quantum communication protocols. We analyze tasks that require either the exchange of single photons in a certain entanglement distribution protocol or beams of light in a continuous-variable quantum key distribution scheme. We find that gravity affects the propagation of photons, therefore acting as a noisy channel for the transmission of information. The effects can be measured with current technology.

  5. Aerospace laser communications technology as enabler for worldwide quantum key distribution

    Science.gov (United States)

    Moll, Florian; Weinfurter, Harald; Rau, Markus; Schmidt, Christopher; Melén, Gwen; Vogl, Tobias; Nauerth, Sebastian; Fuchs, Christian

    2016-04-01

    A worldwide growing interest in fast and secure data communications pushes technology development along two lines. While fast communications can be realized using laser communications in fiber and free-space, inherently secure communications can be achieved using quantum key distribution (QKD). By combining both technologies in a single device, many synergies can be exploited, therefore reducing size, weight and power of future systems. In recent experiments we demonstrated quantum communications over large distances as well as between an aircraft and a ground station which proved the feasibility of QKD between moving partners. Satellites thus may be used as trusted nodes in combination with QKD receiver stations on ground, thereby enabling fast and secure communications on a global scale. We discuss the previous experiment with emphasis on necessary developments to be done and corresponding ongoing research work of German Aerospace Center (DLR) and Ludwig Maximilians University Munich (LMU). DLR is performing research on satellite and ground terminals for the high-rate laser communication component, which are enabling technologies for the QKD link. We describe the concept and hardware of three generations of OSIRIS (Optical High Speed Infrared Link System) laser communication terminals for low Earth orbiting satellites. The first type applies laser beam pointing solely based on classical satellite control, the second uses an optical feedback to the satellite bus and the third, currently being in design phase, comprises of a special coarse pointing assembly to control beam direction independent of satellite orientation. Ongoing work also targets optical terminals for CubeSats. A further increase of beam pointing accuracy can be achieved with a fine pointing assembly. Two ground stations will be available for future testing, an advanced stationary ground station and a transportable ground station. In parallel the LMU QKD source size will be reduced by more than an

  6. Round table on the future of satellite communications and broadcasting in Europe

    Science.gov (United States)

    Bartholome, P.; Burke, W. R.

    1987-08-01

    Organizations that operate or intend to operate satellite systems for telecommunications or broadcasting in Europe (Eutelsat, Telecom 1, ASTRA, Italsat, DFS/Kopernikus, Tele-X, TV-Sat, TDF 1, Olympus/SARIT) explained the reasons that motivated them to set up a network, the services provided, and gave their views on the future of satellites in Europe. Apart from ASTRA, whose motivations were clearly market oriented right from the start, all projects were launched for reasons other than the desire to satisfy a definite requirement in term of new service offerings. However, all organizations are now focusing on distribution of television programs to the public, either directly or via cable networks. The exceptions are TELE-X, which places higher expectations on the success of business services, and Italsat concentrates on advanced-technology and hopes to make a breakthrough in conventional communications.

  7. Star on the horizon: The emergence of the direct broadcast satellite in American mass communications

    Science.gov (United States)

    Thomas, J. H.

    1984-12-01

    The purpose of this thesis is to describe the concept of broadcasting from satellites directly to the viewer equipped with a small, inexpensive receiving antenna, and the evolution of this technology as a means of commercial broadcast. Emphasis is placed on the problems of developing a regulatory framework for DBS by the Federal Communications Commission. The opposition of the existing broadcasters to the unregulated development of direct broadcast satellite (DBS) is explored in light of the possible effect that DBS may have on the economic base, audience, and advertising revenue of existing broadcasters. The information for this study was obtained from government documents, legal journals, books and the popular press. Two basic conclusions are drawn from this study: First, that the existing broadcasters have opposed the marketplace development of DBS, and second, that DBS does not pose as great a threat, at least in the near term, as the broadcasters fear.

  8. 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.

  9. 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.

  10. 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.

  11. Adaptive beamforming in a CDMA mobile satellite communications system

    Science.gov (United States)

    Munoz-Garcia, Samuel G.

    1993-01-01

    Code-Division Multiple-Access (CDMA) stands out as a strong contender for the choice of multiple access scheme in these future mobile communication systems. This is due to a variety of reasons such as the excellent performance in multipath environments, high scope for frequency reuse and graceful degradation near saturation. However, the capacity of CDMA is limited by the self-interference between the transmissions of the different users in the network. Moreover, the disparity between the received power levels gives rise to the near-far problem, this is, weak signals are severely degraded by the transmissions from other users. In this paper, the use of time-reference adaptive digital beamforming on board the satellite is proposed as a means to overcome the problems associated with CDMA. This technique enables a high number of independently steered beams to be generated from a single phased array antenna, which automatically track the desired user signal and null the unwanted interference sources. Since CDMA is interference limited, the interference protection provided by the antenna converts directly and linearly into an increase in capacity. Furthermore, the proposed concept allows the near-far effect to be mitigated without requiring a tight coordination of the users in terms of power control. A payload architecture will be presented that illustrates the practical implementation of this concept. This digital payload architecture shows that with the advent of high performance CMOS digital processing, the on-board implementation of complex DSP techniques -in particular digital beamforming- has become possible, being most attractive for Mobile Satellite Communications.

  12. Use of CDMA access technology in mobile satellite systems

    Science.gov (United States)

    Ramasastry, Jay; Wiedeman, Bob

    1995-01-01

    Use of Code Division Multiple Access (CDMA) technology in terrestrial wireless systems is fairly well understood. Similarly, design and operation of Power Control in a CDMA-based system in a terrestrial environment is also well established. Terrestrial multipath characteristics, and optimum design of the CDMA receiver to deal with multipath and fading conditions are reliably established. But the satellite environment is different. When the CDMA technology is adopted to the satellite environment, other design features need to be incorporated (for example; interleaving, open-loop and closed-loop power control design, diversity characteristics) to achieve comparable level of system performance. In fact, the GLOBALSTAR LEO/MSS system has incorporated all these features. Contrary to some published reports, CDMA retains the advantages in the satellite environment that are similar to those achieved in the terrestrial environment. This document gives a description of the CDMA waveform and other design features adopted for mobile satellite applications.

  13. Laser-based satellite communication systems stabilized by non-mechanical electro-optic scanners

    Science.gov (United States)

    Ziemkiewicz, Michael; Davis, Scott R.; Rommel, Scott D.; Gann, Derek; Luey, Benjamin; Gamble, Joseph D.; Anderson, Mike

    2016-05-01

    Laser communications systems provide numerous advantages for establishing satellite-to-ground data links. As a carrier for information, lasers are characterized by high bandwidth and directionality, allowing for fast and secure transfer of data. These systems are also highly resistant to RF influences since they operate in the infrared portion of the electromagnetic spectrum, far from radio bands. In this paper we will discuss an entirely non-mechanical electro-optic (EO) laser beam steering technology, with no moving parts, which we have used to form robust 400 Mbps optical data connections through air. This technology will enable low cost, compact, and rugged free space optical (FSO) communication modules for small satellite applications. The EO beam-steerer at the heart of this system is used to maintain beam pointing as the satellite orbits. It is characterized by extremely low values for size, weight and power consumption (SWaP) - approximately 300 cm3, 300 g, and 5 W respectively, which represents a marked improvement compared to heavy, and power-consuming gimbal mechanisms. It is capable of steering a 500 mW, 1 mm short wave infrared (SWIR) beam over a field of view (FOV) of up to 50° x 15°, a range which can be increased by adding polarization gratings, which provide a coarse adjust stage at the EO beam scanner output. We have integrated this device into a communication system and demonstrated the capability to lock on and transmit a high quality data stream by modulation of SWIR power.

  14. The Use of Communication Satellites for Distance Education: A World Perspective.

    Science.gov (United States)

    Coldevin, Gary; Amundsen, Cheryl

    1985-01-01

    Reviews communications satellites configurations (point-to-point, distribution, and direct broadcast)and presents an overview of primary uses for satellite communications worldwide, including extension of preparatory and first year university courses; inservice teacher, professional, and continuing education; non-formal education; primary level…

  15. Advanced Microelectronics Technologies for Future Small Satellite Systems

    Science.gov (United States)

    Alkalai, Leon

    1999-01-01

    Future small satellite systems for both Earth observation as well as deep-space exploration are greatly enabled by the technological advances in deep sub-micron microelectronics technologies. Whereas these technological advances are being fueled by the commercial (non-space) industries, more recently there has been an exciting new synergism evolving between the two otherwise disjointed markets. In other words, both the commercial and space industries are enabled by advances in low-power, highly integrated, miniaturized (low-volume), lightweight, and reliable real-time embedded systems. Recent announcements by commercial semiconductor manufacturers to introduce Silicon On Insulator (SOI) technology into their commercial product lines is driven by the need for high-performance low-power integrated devices. Moreover, SOI has been the technology of choice for many space semiconductor manufacturers where radiation requirements are critical. This technology has inherent radiation latch-up immunity built into the process, which makes it very attractive to space applications. In this paper, we describe the advanced microelectronics and avionics technologies under development by NASA's Deep Space Systems Technology Program (also known as X2000). These technologies are of significant benefit to both the commercial satellite as well as the deep-space and Earth orbiting science missions. Such a synergistic technology roadmap may truly enable quick turn-around, low-cost, and highly capable small satellite systems for both Earth observation as well as deep-space missions.

  16. Network design for telemedicine--e-health using satellite technology.

    Science.gov (United States)

    Graschew, Georgi; Roelofs, Theo A; Rakowsky, Stefan; Schlag, Peter M

    2008-01-01

    Over the last decade various international Information and Communications Technology networks have been created for a global access to high-level medical care. OP 2000 has designed and validated the high-end interactive video communication system WinVicos especially for telemedical applications, training of the physician in a distributed environment, teleconsultation and second opinion. WinVicos is operated on a workstation (WoTeSa) using standard hardware components and offers a superior image quality at a moderate transmission bandwidth of up to 2 Mbps. WoTeSa / WinVicos have been applied for IP-based communication in different satellite-based telemedical networks. In the DELTASS-project a disaster scenario was analysed and an appropriate telecommunication system for effective rescue measures for the victims was set up and evaluated. In the MEDASHIP project an integrated system for telemedical services (teleconsultation, teleelectro-cardiography, telesonography) on board of cruise ships and ferries has been set up. EMISPHER offers an equal access for most of the countries of the Euro-Mediterranean area to on-line services for health care in the required quality of service. E-learning applications, real-time telemedicine and shared management of medical assistance have been realized. The innovative developments in ICT with the aim of realizing a ubiquitous access to medical resources for everyone at any time and anywhere (u-Health) bear the risk of creating and amplifying a digital divide in the world. Therefore we have analyzed how the objective needs of the heterogeneous partners can be joined with the result that there is a need for real integration of the various platforms and services. A virtual combination of applications serves as the basic idea for the Virtual Hospital. The development of virtual hospitals and digital medicine helps to bridge the digital divide between different regions of the world and enables equal access to high-level medical care. Pre

  17. Investigating Modern Communication Technologies: The effect of Internet-based Communication Technologies on the Investigation Process

    Directory of Open Access Journals (Sweden)

    Matthew Phillip Simon

    2011-12-01

    Full Text Available Communication technologies are commonplace in modern society. For many years there were only a handful of communication technologies provided by large companies, namely the Public Switched Telephone Network (PSTN and mobile telephony; these can be referred to as traditional communication technologies. Over the lifetime of traditional communication technologies has been little technological evolution and as such, law enforcement developed sound methods for investigating targets using them. With the advent of communication technologies that use the Internet – Internet-based or contemporary communication technologies – law enforcement are faced with many challenges. This paper discusses these challenges and their potential impact. It first looks at what defines the two technologies then explores the laws and methods used for their investigation. It then looks at the issues of applying the current methodologies to the newer and fundamentally different technology. The paper concludes that law enforcement will be required to update their methods in order to remain effective against the current technology trends.

  18. High Spectral Density Optical Communication Technologies

    CERN Document Server

    Nakazawa, Masataka; Miyazaki, Tetsuya

    2010-01-01

    The latest hot topics of high-spectral density optical communication systems using digital coherent optical fibre communication technologies are covered by this book. History and meaning of a "renaissance" of the technology, requirements to the Peta-bit/s class "new generation network" are also covered in the first part of this book. The main topics treated are electronic and optical devices, digital signal processing including forward error correction, modulation formats as well as transmission and application systems. The book serves as a reference to researchers and engineers.

  19. Study of Development of Information and Communication Technology in Azerbaijan with Marketing Approach

    Directory of Open Access Journals (Sweden)

    Rovshan Karimov

    2015-03-01

    Full Text Available This paper is devoted to study of development and also spread of information and communication technology, including activity of mobile operators and telecommunications satellite in Azerbaijan. In the study work, particular emphasis is laid on conducting marketing in order to investigate the current condition of communication technology, and also the role of related subjects of entrepreneurship as key players in the market. With applying marketing, the advantages and also existing problems in this sector are revealed. The carried research allows determine the socioeconomic effect of communication technologies, as well as business strategy and the peculiarities of functioning of mobile operators with taking into consideration interests of customers in Azerbaijan.

  20. Rain Fade Compensation Alternatives for Ka Band Communication Satellites

    Science.gov (United States)

    Acosta, Roberto J.

    1997-01-01

    Future satellite communications systems operating in Ka-band frequency band are subject to degradation produced by the troposphere which is much more severe than those found at lower frequency bands. These impairments include signal absorption by rain, clouds and gases, and amplitude scintillation's arising from refractive index irregularities. For example, rain attenuation at 20 GHz is almost three times that at 11 GHz. Although some of these impairments can be overcome by oversizing the ground station antennas and high power amplifiers, the current trend is using small (less than 20 inches apertures), low-cost ground stations (less than $1000) that can be easily deployed at user premises. As a consequence, most Ka-band systems are expected to employ different forms of fade mitigation that can be implemented relatively easily and at modest cost. The rain fade mitigation approaches are defined by three types of Ka-band communications systems - a low service rate (less than 1.5 Mb/s), a moderate service rate (1.5 to 6 Mb/s) system and a high service rate (greater than 43 Mb/s) system. The ACTS VSAT network, which includes an adaptive rain fade technique, is an example of a moderate service rate.

  1. 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.

  2. Near Field Communication: Technology and Market Trends

    Directory of Open Access Journals (Sweden)

    Gabriella Arcese

    2014-09-01

    Full Text Available Among the different hi-tech content domains, the telecommunications industry is one of the most relevant, in particular for the Italian economy. Moreover, Near Field Communication (NFC represents an example of innovative production and a technological introduction in the telecommunications context. It has a threefold function: card emulator, peer-to-peer communication and digital content access, and it could be pervasively integrated in many different domains, especially in the mobile payment one. The increasing attention on NFC technology from the academic community has improved an analysis on the changes and the development perspective about mobile payments. It has considered the work done by the GSMA (Global System for Mobile Communications Association and the NFC Forum in recent years. This study starts from an analysis of the scientific contributions to Near Field Communication and how the main researches on this topic were conceived. Our focus is on the diffusion rates, the adoption rates and the technology life cycle. After that, we analyze the technical-economical elements of NFC. Finally, this work presents the state of art of the improvements to this technology with a deeper focus on NFC technologies applied to the tourism industry. In this way, we have done a case analysis that shows some of the NFC existent applications linked to each stage of the tourism value chain.

  3. Satellite-aided mobile radio concepts study: Concept definition of a satellite-aided mobile and personal radio communication system

    Science.gov (United States)

    Anderson, R. E.

    1979-01-01

    The satellite system requires the use of a large satellite antenna and spacecraft array power of about 12 kW or more depending on the operating frequency. Technology developments needed include large offset reflector multibeam antennas, satellite electrical power sybsystems providing greater than 12 kW of power, signal switching hardware, and linearized efficient solid state amplifiers for the satellite-aided mobile band. Presently there is no frequency assignment for this service, and it is recommended that an allocation be pursued. The satellite system appears to be within reasonable extrapolation of the state of the art. It is further recommended that the satellite-aided system spacecraft definition studies and supporting technology development be initiated.

  4. Canadian EHF (28/19 GHz) satellite communication terminals for the Olympus program

    Science.gov (United States)

    Pike, C. J.; Bradley, D. R.; Hindson, D. J. M.

    Researchers at the Communications Research Center (CRC) are actively developing extremely high frequency (EHF) technology for the development of the Olympus satellite terminals. The specifications and performance evaluation of the terminals are presented from the radio frequency (RF) perspective as well as the digital approach using 70 MHz modems. Terminals constructed at CRC will be used to conduct experiments in the areas of rain fade countermeasures using an adaptive data rate transmission technique, in on-board processing (OBP) that will be demonstrated in a double-hop configuration using a surface acoustic wave demodulator, and in other user trials related to tele-education, and tele-medicine. Phase shift keyed (PSK) modems will be used for the rain fade countermeasures experiment. Terminals will also be used for demonstrations of point-to-point communications applicable to private business, tele-education and tele-medicine networks.

  5. Mediterranean Conference on Information & Communication Technologies 2015

    CERN Document Server

    Choubani, Fethi; Moussati, Ali

    2016-01-01

    This volume presents the first part of the proceedings of the Mediterranean Conference on Information & Communication Technologies (MedICT 2015), which was held at Saidia, Morocco during 7–9 May, 2015. MedICT provides an excellent international forum to the researchers and practitioners from both academia as well as industry to meet and share cutting-edge development. The conference has also a special focus on enabling technologies for societal challenges, and seeks to address multidisciplinary challenges in Information & Communication Technologies such as health, demographic change, wellbeing, security and sustainability issues. The proceedings publish high quality papers which are closely related to the various theories, as well as emerging and practical applications of particular interest to the ICT community. This first volume provides a compact yet broad view of recent developments in devices, technologies and processing, and covers recent research areas in the field including Microwave Devices...

  6. 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.

  7. Application of Satellite Communication in Emergency%卫星通信在消防应急中的应用

    Institute of Scientific and Technical Information of China (English)

    丁舒羽; 郭阳

    2015-01-01

    突发灾害和自然灾害所造成的损失和破环是十分严重的,预防和处理突发灾害显得尤为重要,所以卫星通信的需求和要求日益增多和提高。应急卫星通信系统不仅要求机动性强,通信无死角,而且要求适用范围广,反应快速,根据这些需求,文章进行了卫星应急通信系统的研究工作。主要讲述了在消防救援中的应用。文章涉及应急通信系统研究的目的、意义、发展现状及趋势;然后从卫星通信技术手段分析了卫星通信的组成和原理等等。%Sudden disasters and the losses caused by natural disasters and the damage is very serious, the prevention and treatment of sudden disaster is particularly important, so the satellite communication needs and requirements are increasing and improving. Emergency satellite communications system requires not only strong mobility, communication is not dead, but also wide application range, fast response, according to these requirements, this paper carried out research work of satellite emergency communication system. Focuses on the application in ifre ifghting and rescue. The purpose, signiifcance, current situation and development trend of the research involving emergency communication system; and then analyzes the composition and principle of satellite communication technology and so on in satellite communication.

  8. Technology Development for High Efficiency Optical Communications

    Science.gov (United States)

    Farr, William H.

    2012-01-01

    Deep space optical communications is a significantly more challenging operational domain than near Earth space optical communications, primarily due to effects resulting from the vastly increased range between transmitter and receiver. The NASA Game Changing Development Program Deep Space Optical Communications Project is developing four key technologies for the implementation of a high efficiency telecommunications system that will enable greater than 10X the data rate of a state-of-the-art deep space RF system (Ka-band) for similar transceiver mass and power burden on the spacecraft. These technologies are a low mass spacecraft disturbance isolation assembly, a flight qualified photon counting detector array, a high efficiency flight laser amplifier and a high efficiency photon counting detector array for the ground-based receiver.

  9. Terahertz wireless communications based on photonics technologies.

    Science.gov (United States)

    Nagatsuma, Tadao; Horiguchi, Shogo; Minamikata, Yusuke; Yoshimizu, Yasuyuki; Hisatake, Shintaro; Kuwano, Shigeru; Yoshimoto, Naoto; Terada, Jun; Takahashi, Hiroyuki

    2013-10-07

    There has been an increasing interest in the application of terahertz (THz) waves to broadband wireless communications. In particular, use of frequencies above 275 GHz is one of the strong concerns among radio scientists and engineers, because these frequency bands have not yet been allocated at specific active services, and there is a possibility to employ extremely large bandwidths for ultra-broadband wireless communications. Introduction of photonics technologies for signal generation, modulation and detection is effective not only to enhance the bandwidth and/or the data rate, but also to combine fiber-optic (wired) and wireless networks. This paper reviews recent progress in THz wireless communications using telecom-based photonics technologies towards 100 Gbit/s.

  10. Communication technologies in the study environment

    DEFF Research Database (Denmark)

    Thorhauge, Anne Mette

    2012-01-01

    In this article, I will analyse and discuss two qualitative case studies concerning ICT in the study environment at the University of Copenhagen, Denmark. I will place special focus on the way in which organisational perspectives as well as technological affordances shape how communication...... and implementation as well as organisational structure as a product of the use of personal media...

  11. School Leadership and Information Communication Technology

    Science.gov (United States)

    Afshari, Mojgan; Bakar, Kamariah Abu; Luan, Wong Su; Samah, Bahaman Abu; Fooi, Foo Say

    2008-01-01

    Leadership is an important component in guiding the teaching-learning process. Principal as school leaders have a major responsibility for initiating and implementing school change through the use of Information and Communication Technology (ICT) and can facilitate complex decision to integrate it into learning, teaching and school administration.…

  12. Management of Information and Communication Technology (ICT ...

    African Journals Online (AJOL)

    Management of Information and Communication Technology (ICT) in ... Bedeviled with sundry crises in the form of staff strikes, student riots, cultism and in ... on the high side, considering the factor of resistance to change as one of the myriad ...

  13. Teaching Responsibly with Technology-Mediated Communication

    Science.gov (United States)

    Veltsos, Jennifer R.; Veltsos, Christophe

    2010-01-01

    Technology-mediated communication, or "new media," such as blogs, Twitter, wikis, and social network sites, can be an endless source of ideas for activities or inspiration for classroom discussion. Many instructors ask students to monitor current events by following keywords and industry leaders on Twitter and reading both corporate and trade…

  14. Empirical modeling of information communication technology usage ...

    African Journals Online (AJOL)

    Hennie

    2015-11-01

    Nov 1, 2015 ... Information Communication Technology (ICT) usage behavior), based on ... highly integrated ICT schemes with competent personnel, using ICTs in .... skilled business teachers, office administrators and ... management of various aspects of the learning ..... Library, 31(6):792-807. doi: 10.1108/EL-04-2012-.

  15. Teaching Responsibly with Technology-Mediated Communication

    Science.gov (United States)

    Veltsos, Jennifer R.; Veltsos, Christophe

    2010-01-01

    Technology-mediated communication, or "new media," such as blogs, Twitter, wikis, and social network sites, can be an endless source of ideas for activities or inspiration for classroom discussion. Many instructors ask students to monitor current events by following keywords and industry leaders on Twitter and reading both corporate and…

  16. An assessment of information communication technology content ...

    African Journals Online (AJOL)

    An assessment of information communication technology content, context and process dimensions in public health facilities in Machakos and Nairobi ... to lack of support from hospital top management team (χ 9.44, d.f.=4 and p=0.005).

  17. INTERNAL COMMUNICATION, THE PROGRESS OF TECHNOLOGY AND SUSTAINABLE DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    CRISTINA ANDREI

    2014-05-01

    Full Text Available Sustainable development involves the broad public participation including the national, regional and local authorities, business and industry, civil society, all major groups – women, children and youth, all workers, trade unions and families. Not only organizations but also employees have a role to play in applying sustainable development in their jobs because their decisions taken every day have an environmental impact. Communication within organization is used as a means to coordinate information exchange and to establish effective coordination of activities between the members of organization. Internet, e-mail, mobile phones, satellite and wireless have had an effect on the way in which information is exchanged and on how people communicate not only in their day-to-day life but also within in the organizations they belong to. New communication technologies have increased the possibilities for a better access to information for employees and made possible to have their voices heard from their colleagues to superior levels, offering the possibility of a two-way communication and creating the potential for greater understanding and dialogue between them. Besides increasing profits, saving time and costs, the use of e-communication within organizations, offer the convenience of combating environmental damage through cutting back on paper and ink usage

  18. Land Mobile Satellite Service (LMSS): A conceptual system design and identification of the critical technologies. Part 1: Executive summary

    Science.gov (United States)

    Naderi, F. (Editor)

    1982-01-01

    A system design for a satellite aided land mobile service is described. The advanced system is based on a geostationary satellite which employs a large UHF reflector to communicate with small user antennas on mobile vehicles. It is shown that the system through multiple beam antennas and frequency reuse provides for radiotelephone and dispatch channels. It is concluded that the system is technologically feasible to provide service to rural and remote regions.

  19. High throughput satellites in 5G and MIMO interference limited communications

    Directory of Open Access Journals (Sweden)

    Pérez-Neria Ana

    2016-01-01

    Full Text Available Classically, thermal noise has been the workhorse of satellite communications due to the long distances to be covered between the satellite and the user terminal (UT. Lately, LDPC (Low-Density Parity-Check codes allow the noise threshold to be set very close to the Shannon limit for the memory-less satellite channel; thus, solving the noise problem that turbo codes were not able to solve. However, recently, the high target rates in next generation 5G wireless terrestrial system are pushing the required spectral efficiency in Satellite Communications; therefore, shifting the SatCom paradigm towards an interference limited one. This paper revisits the 5G scene and the role of next generation satellite communications, with a special focus on high throughput satellites (HTS together with the future accompanying MIMO interference mitigation techniques.

  20. Communications and technology for violence prevention: workshop summary

    National Research Council Canada - National Science Library

    Blakeslee, Katherine M; Patel, Deepali; Simon, Melissa A

    2012-01-01

    .... At the same time, new communications technologies and distribution channels have altered traditional means of communications, and have made community-based efforts to prevent violence possible...

  1. Performance tests of a satellite-based asymmetric communication network for the 'hyper hospital'.

    Science.gov (United States)

    Yamaguchi, T

    1997-01-01

    The Hyper Hospital is a prototype networked telemedicine system which uses virtual reality. We measured the performance of a novel multimedia network based on satellite communications. The network was a hybrid system consisting of a satellite channel in one direction and a terrestrial channel in the other. Each user was equipped with a standard satellite communication receiver and a telephone connection. Requests from the users were sent by modern and telephone line and responses were received by satellite. The user requests were initiated by clicking buttons on a World Wide Web browser screen. The transmission rates of satellite and normal telephone-line communications were compared for standardized text data. Satellite communication was three to five times faster. The transmission rate was also measured for standardized graphical data (GIF format). With a file size of about 400 kByte, satellite-mediated communication was 10 times faster than telephone lines. The effect of simultaneous access on performance was also explored. For simultaneous access of nine users to a single graphics file, 78% of the transmission speed was obtained in comparison with that of a single user. The satellite-based system showed excellent high-speed communication performance, particularly for multimedia data.

  2. Future Aeronautical Communication Infrastructure Technology Investigation

    Science.gov (United States)

    Gilbert, Tricia; Jin, Jenny; Bergerm Jason; Henriksen, Steven

    2008-01-01

    This National Aeronautics and Space Administration (NASA) Contractor Report summarizes and documents the work performed to investigate technologies that could support long-term aeronautical mobile communications operating concepts for air traffic management (ATM) in the timeframe of 2020 and beyond, and includes the associated findings and recommendations made by ITT Corporation and NASA Glenn Research Center to the Federal Aviation Administration (FAA). The work was completed as the final phase of a multiyear NASA contract in support of the Future Communication Study (FCS), a cooperative research and development program of the United States FAA, NASA, and EUROCONTROL. This final report focuses on an assessment of final five candidate technologies, and also provides an overview of the entire technology assessment process, including final recommendations.

  3. 77 FR 51045 - Certain Two-Way Global Satellite Communication Devices, System and Components Thereof; Notice of...

    Science.gov (United States)

    2012-08-23

    ... COMMISSION Certain Two-Way Global Satellite Communication Devices, System and Components Thereof; Notice of... Commission has received a complaint entitled Certain Two-Way Global Satellite Communication Devices, System... satellite communication devices, systems. The complaint names as respondents Delorme Publishing Company Inc...

  4. Technology status of HNF-based monopropellants for satellite propulsion

    NARCIS (Netherlands)

    Marée, A.G.M.; Moerel, J.L.P.A.; Weiland-Veltmans, W.H.M.; Wierkx, F.J.M.; Zevenbergen, J.

    2004-01-01

    This paper reports on significant technological progress made over the last few years in determining the feasibility of HNF-based monopropellants. An HNF-based monopropellant is an interesting alternative for hydrazine as monopropellant for satellite propulsion. New non-toxic monopropellants based o

  5. Technology status of HNF-based monopropellants for satellite propulsion

    NARCIS (Netherlands)

    Marée, A.G.M.; Moerel, J.L.P.A.; Weiland-Veltmans, W.H.M.; Wierkx, F.J.M.; Zevenbergen, J.

    2004-01-01

    This paper reports on significant technological progress made over the last few years in determining the feasibility of HNF-based monopropellants. An HNF-based monopropellant is an interesting alternative for hydrazine as monopropellant for satellite propulsion. New non-toxic monopropellants based o

  6. Satellite Technology Contribution to Water and Food Security

    Science.gov (United States)

    Brown, Molly E.

    2010-01-01

    This slide presentation reviews the issue of supplies of food, the relationship to food security, the ability of all people to attain sufficient food for an active and healthy life, and the ability to use satellite technology and remote sensing to assist with planning and act as an early warning system.

  7. Progress on the use of satellite technology for gravity exploration

    Directory of Open Access Journals (Sweden)

    Yanwei Ding

    2015-07-01

    Full Text Available In this paper, the technological progress on Chinese gravity exploration satellites is presented. Novel features such as ultra-stable structure, high accurate thermal control, drag-free and attitude control, micro-thrusters, aerodynamic configuration, the ability to perform micro-vibration analyses, microwave ranging system and mass center trimmer are described.

  8. A Scheme to Improve Throughput for ARQ-Protected Satellite Communication

    Science.gov (United States)

    Friedman, Daniel; Ephremides, Anthony

    1997-01-01

    Automatic-repeat-request (ARQ) error control is often employed to assure high fidelity information transmission. However, ARQ error control can provide poor throughput for satellite multicasting. The throughput in such communication may be improved by the combination of a terrestrial network parallel to the satellite network and a judiciously modified ARQ protocol. In particular, retransmitted ARQ frames can be sent terrestrially in such a hybrid network, allowing higher throughput than in a pure-satellite network. This work presents analytic results to establish the potential for improving the throughput of satellite multicast communication employing ARQ error control by the adoption of such a hybrid network architecture.

  9. 78 FR 19172 - Earth Stations Aboard Aircraft Communicating with Fixed-Satellite Service Geostationary-Orbit...

    Science.gov (United States)

    2013-03-29

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Parts 2 and 25 Earth Stations Aboard Aircraft Communicating with Fixed-Satellite Service Geostationary-Orbit Space Stations AGENCY: Federal Communications Commission. ACTION: Proposed rule;...

  10. Communication technologies and emotionality in transnational families

    Directory of Open Access Journals (Sweden)

    María Guadalupe Ramírez Contreras

    2014-07-01

    Full Text Available It was estimated in 2009 that 11,500.0 millions Mexican immigrants were living in the United States (Pew Hispanic Center, 2009. However, such immigrants can’t take their families with them to the US breaking-up of the family unit. Therefore, immigrants and their families become members of a transnational family.  In order to cope with such family break-up, members of such families try to balance themselves through developing an emotional intimacy using communication technologies. However, what kind of emotional support is offered when one of the members of the transnational family is a senior citizen and chronically ill? What kind of emotions do these transnational families experience? Which communication technologies do they use to be in touch? How these communication technologies are related to the emotional support? In order to answer these research questions, I explored previous studies in which I found that they only included the immigrants’ point of view. To overcome this limitation in this study, I included the point of view of all members of transnational families. I conducted a qualitative study. It took place in Sahuayo, Michoacan. I interviewed members of 15 transnational families during 2012 and 2013. The results showed that emotional support was identified as: a contacting relatives in Mexico, initiated by immigrants, b exchanging daily life experiences; c solving issues and conflicts; and d immigrants supporting, participating or being virtually in special celebrations. Immigrants also used communication technologies in order to maintain emotional ties and give emotional support to their parents. The communication help immigrants to provide the emotional support to their parents and also to express their feelings. I recommend studying national migrants and rural populations, in order to analyse any differences between them and my sample.

  11. An Enhanced Multiple Random Access Scheme for Satellite Communications

    CERN Document Server

    Bui, Huyen-Chi; Boucheret, Marie-Laure

    2011-01-01

    In this paper, we introduce Multi-Slots Coded ALOHA (MuSCA) as a multiple random access method for satellite communications. This scheme can be considered as a generalization of the Contention Resolution Diversity Slotted Aloha (CRDSA) mechanism. Instead of transmitting replicas, this system replaces them by several parts of a single word of an error correcting code. It is also different from Coded Slotted ALOHA (CSA) as the assumption of destructive collisions is not adopted. In MuSCA, the entity in charge of the decoding mechanism collects all bursts of the same user (including the interfered slots) before decoding and implements a successive interference cancellation (SIC) process to remove successfully decoded signals. Simulations show that for a frame of 100 slots, the achievable total normalized throughput is greater than 1.25 and 1.4 for a frame of 500 slots, resulting in a gain of 80% and 75% with respect to CRDSA and CSA respectively. This paper is a first analysis of the proposed scheme and opens se...

  12. Orbital performance of communication satellite microwave power amplifiers (MPAs)

    Science.gov (United States)

    Strauss, R.

    1993-01-01

    This paper presents background data on the performance of microwave power amplifiers (MPAs) used as transmitters in currently operating commercial communication satellites. Specifically aspects of two competing MPA types are discussed. These are well known TWTA (travelling wave tube amplifier) and the SSPA (solid state power amplifier). Extensive in-orbit data has been collected from over 2000 MPAs in 1991 and 1993. The study in 1991 invovlved 75 S/C (spacecraft) covering 463 S/C years. The 1993 'second-look' study encompassed a slightly different population of 72 S/C with 497 S/C years of operation. A surprising result of both studies was that SSPAs, although quite reliable, did not achieve the reliability of TWTAs were one-third more reliable in the 1993 study. This was at C-band with comparable power amplifiers, e.g. 6-16W of RF output power and similar gains. Data at K(sub u)-band is for TWTAs only since there are no SSPAs in the current S/C inventory. The other complementary result was that the projected failure rates used as S/C payload design guidelines were, on average, somewhat higher for TWTAs than the actual failure rates uncovered by this study. SSPA rates were as projected.

  13. Information and Communication Technologies in Engineering Education

    Directory of Open Access Journals (Sweden)

    Maldague Xavier

    2016-01-01

    Full Text Available In the emerging digital era it is difficult to train highly-skilled, competent specialists without the use of information and communication technology (ICT. The use of ICT in education increases the motivation to learn, stimulates cognitive activity and independent work, facilitates information exchange, enables interactive communication between teachers and students, and improves learning outcomes. This paper reviews the literature regarding the use of ICTs in education, explores their advantages and challenges, and surveys first-year students at the Institute of Non-Destructive Testing, National Research Tomsk Polytechnic University to determine their attitude toward ICT in foreign language learning.

  14. Satellite remote-sensing technologies used in forest fire management

    Institute of Scientific and Technical Information of China (English)

    TIAN Xiao-rui; Douglas J. Mcrae; SHU Li-fu; WANG Ming-yu; LI Hong

    2005-01-01

    Satellite remote sensing has become a primary data source for fire danger rating prediction, fuel and fire mapping, fire monitoring, and fire ecology research. This paper summarizes the research achievements in these research fields, and discusses the future trend in the use of satellite remote-sensing techniques in wildfire management. Fuel-type maps from remote-sensing data can now be produced at spatial and temporal scales quite adequate for operational fire management applications. US National Oceanic and Atmospheric Administration (NOAA) and Moderate Resolution Imaging Spectroradiometer (MODIS) satellites are being used for fire detection worldwide due to their high temporal resolution and ability to detect fires in remote regions. Results can be quickly presented on many Websites providing a valuable service readily available to fire agency. As cost-effective tools, satellite remote-sensing techniques play an important role in fire mapping. Improved remote-sensing techniques have the potential to date older fire scars and provide estimates of burn severity. Satellite remote sensing is well suited to assessing the extent of biomass burning, a prerequisite for estimating emissions at regional and global scales, which are needed for better understanding the effects of fire on climate change. The types of satellites used in fire research are also discussed in the paper. Suggestions on what remote-sensing efforts should be completed in China to modernize fire management technology in this country are given.

  15. A Fast, Affordable, Science and Technology SATellite (FASTSAT) and the Small Satellite Market Development Environment

    Science.gov (United States)

    Boudreaux, Mark; Montgomery, Edward; Cacas, Joseph

    2008-01-01

    The National Aeronautics and Space Administr ation at Marshall Space Flight Center and the National Space Science and Technology Center in Huntsville Alabama USA, are jointly developing a new class of science and technology mission small satellites. The Fast, Affordable, Science and Technology SATell ite (FASTSAT) was designed and developed using a new collaborative and best practices approach. The FASTSAT development, along with the new class of low cost vehicles currently being developed, would allow performance of 30 kg payload mass missions for a cost of less than 10 million US dollars.

  16. Environmental effects of information and communications technologies.

    Science.gov (United States)

    Williams, Eric

    2011-11-16

    The digital revolution affects the environment on several levels. Most directly, information and communications technology (ICT) has environmental impacts through the manufacturing, operation and disposal of devices and network equipment, but it also provides ways to mitigate energy use, for example through smart buildings and teleworking. At a broader system level, ICTs influence economic growth and bring about technological and societal change. Managing the direct impacts of ICTs is more complex than just producing efficient devices, owing to the energetically expensive manufacturing process, and the increasing proliferation of devices needs to be taken into account.

  17. INNOVATION TRENDS ON INFORMATION AND COMMUNICATION TECHNOLOGIES

    Directory of Open Access Journals (Sweden)

    Radu CURETEANU

    2010-12-01

    Full Text Available The importance of innovation was long underestimated in service activities. In contrast to the radical innovations vital to growth in manufacturing sectors, innovations in services and tourism were secondary and capital-scarce, and for this reason they were excluded from the scope of government interest and action. It is interesting to note that the discourse changed with the emergence of new information and communication technologies, which have been especially influential in the realm of tourism.

  18. Assessment of a satellite power system and six alternative technologies

    Energy Technology Data Exchange (ETDEWEB)

    Wolsko, T.; Whitfield, R.; Samsa, M.; Habegger, L.S.; Levine, E.; Tanzman, E.

    1981-04-01

    The satellite power system is assessed in comparison to six alternative technologies. The alternatives are: central-station terrestrial photovoltaic systems, conventional coal-fired power plants, coal-gasification/combined-cycle power plants, light water reactor power plants, liquid-metal fast-breeder reactors, and fusion. The comparison is made regarding issues of cost and performance, health and safety, environmental effects, resources, socio-economic factors, and insitutional issues. The criteria for selecting the issues and the alternative technologies are given, and the methodology of the comparison is discussed. Brief descriptions of each of the technologies considered are included. (LEW)

  19. Information and communication technology in Home Economic class

    OpenAIRE

    Beronja, Jana

    2014-01-01

    The diploma thesis defines information and communication technology, its involvement in educational processes; the legislation in the field of integration of information and communication technology in the teaching process and the impact of progress in information and communication technology on its use in class are presented. Followed by a short historical overview of the application of information and communication technology in educational processes. In the empirical part the results o...

  20. Potentials and Limitations of CDMA Networks for Combined Inter-Satellite Communication and Relative Navigation

    NARCIS (Netherlands)

    Sun, R.; Guo, J.; Gill, E.K.A.; Maessen, D.C.

    2012-01-01

    Precision formation flying missions require formation acquisition and maintenance through the interactions among spacecraft by the inter-satellite communication and relative navigation. This paper analyses the dedicated system constraints of the network architecture for precision formation flying mi

  1. 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.

  2. Beam forming networks for mm-wave satellite communications

    Science.gov (United States)

    Sharon, T. E.

    1983-01-01

    Technology features of a beam forming network (BFN) employing ferrite devices to provide multiple beam antenna pattern control for satellites used in telecommunications are described. The BFN produces the phase and amplitude distribution for each horn in an antenna array, with the number of horns in the array being equal to the number of outputs in the BFN. One configuration involves microwave switches and permits illumination of a single feed horn at a time using ferrite latching circulators that function by reversing the circulation direction. A more flexible version, yielding a variable amplitude distribution across the feed horn array to accommodate changing traffic patterns or serving a TDMA system, includes the capability of forming nulls in the system with a variable phase shifter in the input ports. The antenna scan angles in phased arrays can be limited to 8 deg from center. Acceptable insertion losses have been demonstrated in BFN with hundreds of ports and switching rates as high as 10 kHz.

  3. Beam forming networks for mm-wave satellite communications

    Science.gov (United States)

    Sharon, T. E.

    1983-08-01

    Technology features of a beam forming network (BFN) employing ferrite devices to provide multiple beam antenna pattern control for satellites used in telecommunications are described. The BFN produces the phase and amplitude distribution for each horn in an antenna array, with the number of horns in the array being equal to the number of outputs in the BFN. One configuration involves microwave switches and permits illumination of a single feed horn at a time using ferrite latching circulators that function by reversing the circulation direction. A more flexible version, yielding a variable amplitude distribution across the feed horn array to accommodate changing traffic patterns or serving a TDMA system, includes the capability of forming nulls in the system with a variable phase shifter in the input ports. The antenna scan angles in phased arrays can be limited to 8 deg from center. Acceptable insertion losses have been demonstrated in BFN with hundreds of ports and switching rates as high as 10 kHz.

  4. Validation of the Information/Communications Technology Literacy Test

    Science.gov (United States)

    2016-10-01

    Technical Report 1360 Validation of the Information / Communications Technology Literacy Test D. Matthew Trippe Human Resources Research...TITLE AND SUBTITLE Validation of the Information / Communications Technology Literacy Test 5a. CONTRACT OR GRANT NUMBER W91WAS-09-D-0013 5b...validate a measure of cyber aptitude, the Information / Communications Technology Literacy Test (ICTL), in predicting trainee performance in Information

  5. Design for an Analysis and Assessment of the Education Satellite Communications Demonstration: Final Report.

    Science.gov (United States)

    Practical Concepts, Inc., Washington, DC.

    A 3-month evaluation design effort developed a strategy and implementation plan for a policy level evaluation of the Educational Satellite Communications Demonstration (ESCD). The final report of the effort covers: (1) development of the evaluation strategy and plan; (2) data collection and analysis; (3) measurement of the impact of satellite TV…

  6. A Highly Secure Identity-Based Authenticated Key-Exchange Protocol for Satellite Communication

    NARCIS (Netherlands)

    Zhong Yantao, [No Value; Ma Jianfeng, [No Value

    2010-01-01

    In recent years, significant improvements have been made to the techniques used for analyzing satellite communication and attacking satellite systems. In 2003, a research team at Los Alamos National Laboratory, USA, demonstrated the ease with which civilian global positioning system (GPS) spoofing a

  7. A Highly Secure Identity-Based Authenticated Key-Exchange Protocol for Satellite Communication

    NARCIS (Netherlands)

    Zhong Yantao, [No Value; Ma Jianfeng, [No Value

    2010-01-01

    In recent years, significant improvements have been made to the techniques used for analyzing satellite communication and attacking satellite systems. In 2003, a research team at Los Alamos National Laboratory, USA, demonstrated the ease with which civilian global positioning system (GPS) spoofing a

  8. Functions of retired GEO communication satellites in improving the PDOP value of CAPS

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    This paper briefly introduces the maneuverable feature of the slightly inclined geosynchronous orbit (SIGSO) satellites under a new control model degraded from the geosynchronous orbit (GEO) communication satellites which will retire as most of the fuel in these satellites has been consumed. Basing on the transmitting Chinese Area Positioning System (CAPS), the authors, by analyses, indicate that such satellites can make an improvement to CAPS constellation configuration, especially to the PDOP value from simulation. The results show that the use of SIGSO satellites can (1) actualize three-dimensional (3D) navigation and positioning compared with the situation, which, only using GEO satellites, cannot be carried out, and improve navigation and positioning accuracy to some extent; (2) reuse the communication services of these satellites for more years, and GEO communication satellites will be retired at a later time and delay their time to become space debris and reduce their pollution of the space environment, so that valuable space resources are maximally used. As for the use of these satellites in the transmitting positioning system, the authors present some views and suggestions in this work.

  9. Functions of retired GEO communication satellites in improving the PDOP value of CAPS

    Institute of Scientific and Technical Information of China (English)

    HAN YanBen; MA LiHua; QIAO QiYuan; YIN ZhiQiang; SHI HuLi; AI GuoXiang

    2009-01-01

    This paper briefly Introduces the maneuverable feature of the slightly Inclined geosynchronous orbit (SlGSO) satellites under e new control model degraded from the geosynchronous orbit (GEO) communication satellites which will retire as most of the fuel in these satellites has been consumed.Basing on the transmitting Chinese Area Positioning System (CAPS),the authors,by analyses,indicate that such satellites can make an improvement to CAPS constellation configuration,especially to the PDOP value from simulation.The results show that the use of SIGSO satellites can (1) actualize three-dimensional (3D) navigation and positioning compared with the situation,which,only using GEO satellites,cannot be carried out,and improve navigation and positioning accuracy to some extent; (2) reuse the communication services of these satellites for more years,and GEO communication satellites will be retired at a later time and delay their time to become space debris and reduce their pollution of the apace environment,so that valuable space resources are maximally used.As for the use of these satellites in the transmitting positioning system,the authors present some views and suggestions in this work.

  10. Pervasive E-health services using the DVB-RCS communication technology.

    Science.gov (United States)

    Vouyioukas, Demosthenes; Maglogiannis, Ilias; Pasias, Vasilios

    2007-08-01

    Two-way satellite broadband communication technologies, such as the Digital Video Broadcasting with Return Channel via Satellite (DVB-RCS) technology, endeavour to offer attractive wide-area broadband connectivity for telemedicine applications, taking into consideration the available data rates, Quality of Service (QoS) provision, survivability, flexibility and operational costs, even in remote areas and isolated regions where the terrestrial technologies suffer. This paper describes a wide-area tele-medicine platform, specially suited for homecare services, based on the DVB-RCS and Wi-Fi communication technologies. The presented platform combines medical data acquisition and transfer, patient remote monitoring and teleconference services. Possible operational scenarios concerning this platform and experimental results regarding tele-monitoring, videoconference and medical data transfer are also provided and discussed in the paper.

  11. An Anonymity Revocation Technology for Anonymous Communication

    Science.gov (United States)

    Antoniou, Giannakis; Batten, Lynn; Parampalli, Udaya

    A number of privacy-enhancing technologies (PETs) have been proposed in the last three decades offering unconditional communication anonymity to their users. Unconditional anonymity can, however, be a security threat because it allows users to employ a PET in order to act maliciously while hiding their identity. In the last few years, several technologies which revoke the identity of users who use PETs have been proposed. These are known as anonymity revocation technologies (ARTs). However, the construction of ARTs has been developed in an ad hoc manner without a theoretical basis outlining the goals and underlying principles. In this chapter we present a set of fundamental principles and requirements for construction of an ART, identifying the necessary features. We then propose an abstract scheme for construction of an ART based on these features.

  12. Household's use of information and communication technologies

    DEFF Research Database (Denmark)

    Jensen, Jesper Ole; Gram-Hanssen, Kirsten; Røpke, Inge

    2009-01-01

    Increasing consumption of electricity due to a growing number of information and communication technology (ICT) appliances in households is a major challenge to reducing energy consumption. Several studies have predicted escalating ICT-related energy consumption, but relatively little has been said....... Through presentation and discussion of qualitative interviews with families having extensive ICT use in their everyday lives, the interviews illustrate how users domesticate and use technologies in many different ways. The interviews reveal a variety of practices and dynamics in different aspects...... of everyday life, including sport, shopping, entertainment and different hobbies. The growing electricity consumption related to ICT is thus as dependent on the consumers' use and domestication of the technologies as on the energy efficiency of the appliances. By analysing the interviews with the use...

  13. Prospective teachers information and communication technology metaphors

    Directory of Open Access Journals (Sweden)

    Ömür Akdemir

    2015-04-01

    Full Text Available Determination of the perceptions of the prospective teachers for the Information and Communications Technology (ICT terms have a remarkable potential to provide input for technology integration plans and ICT trainings. Within this context, the purpose of this study is to discover the metaphors constructed by prospective teachers for the ICT terms. Data were gathered from 180 prospective teachers through survey. 977 valid metaphors constructed by the participants were grouped into conceptual categories for the six ICT terms. The most common conceptual categories are “developing and changing” for technology, “making life easy” for computers and search engines, “limitless and endless” for the Internet, “means of communication” for social networks, and “addictive items” for video games. Future research should concentrate on investigating the match and mismatches between intended use of the ICT tools and the perception of the prospective teachers.

  14. CAPS satellite spread spectrum communication blind multi-user detecting system based on chaotic sequences

    Institute of Scientific and Technical Information of China (English)

    LEI LiHua; SHI HuLi; MA GuanYi

    2009-01-01

    Multiple Path Interference (MPI) and Multiple Access Interference (MAI) are Important factors that affect the performance of Chinese Area Positioning System (CAPS),These problems can be solved by using spreading sequences with ideal properties and multi-user detectors.Chaotic sequences based on Chebyshev map are studied and the satellite communication system model is set up to investigate the application of chaotic sequences for CAPS in this paper,Simulation results show that chaotic sequences have desirable correlation properties and it is easy to generate a large number of chaotic sequences with good security.It has great practical value to apply chaotic sequences to CAPS together with multi-user detecting technology and the system performance can be improved greatly.

  15. CAPS satellite spread spectrum communication blind multi-user detecting system based on chaotic sequences

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Multiple Path Interference (MPI) and Multiple Access Interference (MAI) are important factors that affect the performance of Chinese Area Positioning System (CAPS). These problems can be solved by using spreading sequences with ideal properties and multi-user detectors. Chaotic sequences based on Chebyshev map are studied and the satellite communication system model is set up to investigate the application of chaotic sequences for CAPS in this paper. Simulation results show that chaotic sequences have desirable correlation properties and it is easy to generate a large number of chaotic sequences with good security. It has great practical value to apply chaotic sequences to CAPS together with multi-user detecting technology and the system performance can be improved greatly.

  16. 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.

  17. Proceedings of the Workshop on Advanced Network and Technology Concepts for Mobile, Micro, and Personal Communications

    Science.gov (United States)

    Paul, Lori (Editor)

    1991-01-01

    The Workshop on Advanced Network and Technology Concepts for Mobile, Micro, and Personal Communications was held at NASA's JPL Laboratory on 30-31 May 1991. It provided a forum for reviewing the development of advanced network and technology concepts for turn-of-the-century telecommunications. The workshop was organized into three main categories: (1) Satellite-Based Networks (L-band, C-band, Ku-band, and Ka-band); (2) Terrestrial-Based Networks (cellular, CT2, PCN, GSM, and other networks); and (3) Hybrid Satellite/Terrestrial Networks. The proceedings contain presentation papers from each of the above categories.

  18. Cultural Deterritorialisation: Communications Technology, Provenance and Place

    Directory of Open Access Journals (Sweden)

    Aleksandra Bida

    2009-07-01

    Full Text Available The deterritorialisation, or uprooting from time and place, of culture through communication technologies can be explored through John Tomlinson's idea of globalisation as "complex connectivity". This paper aims to cover various areas of research to highlight the ways in which cultural deterritorialisation continually permeates cultural experience. The analysis is grounded in an understanding of globalisation as both a homogenising and differentiating force. Three aspects of communication's "complex connectivity" are looked at in greater detail: control, speed/ease, and the idea of a global village. These are discussed in terms of ownership and market concentration, and notions of "direct connectivity" and "indirect connectivity". Adapted from Tomlinson's "complex connectivity", "direct connectivity" focuses on interpersonal relations and deterritorialisation on individual scales through personal global contact, while "indirect connectivity" enlarges the scale with a focus on mass cultural production and global consumption. Finally, a discussion of possible kinds of reterritorialisation will consider the impact of these aspects of communication's "complex connectivity" on cultural flows. Rather than concepts such as transterritoriality which are not rooted and remain deterritorialised, reterritorialisation is explored as a means of balancing global trends in the cultural and communications sectors of global and local villages alike.

  19. Acquisition cost analysis for the near term military application of laser versus millimeter wave for satellite crosslink communications

    Science.gov (United States)

    Marlow, S. W.

    1983-12-01

    Two alternative satellite communication technologies have evolved independently of each other and now seem to be in direct competition for limited R&D dollars. In an attempt to identify which technology is best, this study concentrates on one aspect of satellite communications - intersatellite crosslinks which are capable of processing one to ten megabits of data per second. The analysis effort is further limited to comparisons of procurement costs and factors which influence these costs. The RCA PRICE Model is used to estimate costs of crosslink subsystems. Extensive review of the literature, as well as design estimates from experts, is necessary to provide the PRICE Model with sufficient details to produce a credible cost figure. A modified Delphi method is used to aggregate the estimates of the experts. From the cost comparison of laser versus millimeter wave crosslink systems, it seems that millimeter wave with its more mature technology has the cost advantage. However, as laser technology reaches a level of maturity close to that of millimeter wave, the difference in procurement costs should become minimal. There are eleven technical, operational, and cost factors which must be analyzed to adequately determine which technology is best. Procurement cost analysis by itself does not determine which technology should be continued or stopped.

  20. G. Marconi: A Data Relay Satellite for Mars Communications

    Science.gov (United States)

    Dionisio, C.; Marcozzi, M.; Landriani, C.

    2002-01-01

    Mars has always been a source of intrigue and fascination. Recent scientific discoveries have stimulated this longstanding interest, leading to a renaissance in Mars exploration. Future missions to Mars will be capable of long-distance surface mobility, hyperspectral imaging, subsurface exploration, and even life-detection. Manned missions and, eventually, colonies may follow. No mission to the Red Planet stands alone. New scientific and technological knowledge is passed on from one mission to the next, not only improving the journey into space, but also providing benefits here on Earth. The Mars Relay Network, an international constellation of Mars orbiters with relay radios, directly supports other Mars missions by relaying communications between robotic vehicles at Mars and ground stations on Earth. The ability of robotic visitors from Earth to explore Mars will take a gigantic leap forward in 2007 with the launch of the Guglielmo Marconi Orbiter (GMO), the first spacecraft primarily dedicated to providing communication relay, navigation and timing services at Mars. GMO will be the preeminent node of the Mars Relay Network. GMO will relay communications between Earth and robotic vehicles near Mars. GMO will also provide navigation services to spacecraft approaching Mars. GMO will receive transmissions from ground stations on Earth at X-band and will transmit to ground stations on Earth at X- and Ka-bands. GMO will transmit to robotic vehicles at Mars at UHF and receive from these vehicles at UHF and X-band. GMO's baseline 4450 km circular orbit provides complete coverage of the planet for telecommunication and navigation support. GMO will arrive at Mars in mid-2008, just before the NetLander and Mars Scout missions that will be its first users. GMO is designed for a nominal operating lifetime of 10 years and will support nominal commanding and data acquisition, as well as mission critical events such as Mars Orbit Insertion, Entry, Descent and Landing, and Mars

  1. 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.

  2. 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.

  3. PEACESAT (Pan Pacific Education and Communication Experiments by Satellite) Project Early Experience: The Design and Early Years of the First Educational Communication Satellite Experiment. Report 1.

    Science.gov (United States)

    Hawaii Univ., Honolulu.

    The PEACESAT Project (Pan Pacific Education and Communication Experiments by Satellite) has been in daily operation for four years since April 1971. Initiated as an individual research project of a university faculty member, it has expanded to involve educational institutions in 12 countries or jurisdictions in the Pacific Basin. These…

  4. Quantum communication and other quantum information technologies

    CSIR Research Space (South Africa)

    Roux, FS

    2014-02-01

    Full Text Available phase screen calculations: 0 1 2 3 w 0/r0 −0.2 0 0.2 0.4 0.6 0.8 1 1.2 1.4 T a n g l e l = 1 l = 2 l = 3 l = 4 l = 5 l = 6 l = 7 – p. 40/41 Conclusions ⊲ Quantum communication, which enables fundamentally secure communication, is a new technology...) = ∫∫ E∗m(r1)En(r2)ψ(r1)ψ∗(r2) × exp [ −12Dθ (|r1 − r2|) ] d2r1 d2r2 Function of only w 0/r0 (contains all parameters including z) Evaluated at z = 0 aC. Paterson, Phys. Rev. Lett., 94, 153901 (2005) – p. 22/41 Entanglement decay Decay of qubit OAM...

  5. The use of communication technology in medicine

    Science.gov (United States)

    Reis, Howard P.

    1991-01-01

    NYNEX Science and Technology is engineering a multi-layered approach to multimedia communications by combining high-resolution images, video, voice, and text into a new fiber-optic service. The service, Media Broadband Service (MBS), is a network-based visual communications capability. It permits real time sharing of images in support of collaborative work among geographically dispersed locations. The health care industry was identified as a primary target market due to their need for high resolution images, the need to transport these images over great distances, and the need to achieve the transport in a short amount of time. The NYNEX Corporation, the current state of the MBS project, including the market needs driving the development of MBS, the overall design of the service, its current implementation and development status, and the progress of MBS projects underway for various customers participating in the initial service offering are described.

  6. Future information communication technology and applications

    CERN Document Server

    Kim, Jung; Sahama, Tony; Yang, Chung-Huang; 2013 International Conference on Future Information & Communication Engineering (ICFICE 2013)

    2013-01-01

    These proceedings are based on the 2013 International Conference on Future Information & Communication Engineering (ICFICE 2013), which will be held at Shenyang in China from June 24-26, 2013. The conference is open to all over the world, and participation from Asia-Pacific region is particularly encouraged. The focus of this conference is on all technical aspects of electronics, information, and communications ICFICE-13 will provide an opportunity for academic and industry professionals to discuss the latest issues and progress in the area of FICE. In addition, the conference will publish high quality papers which are closely related to the various theories and practical applications in FICE. Furthermore, we expect that the conference and its publications will be a trigger for further related research and technology improvements in this important subject.  "This work was supported by the NIPA (National IT Industry Promotion Agency) of Korea Grant funded by the Korean Government (Ministry of Science, ICT...

  7. SpaceWire model development technology for satellite architecture.

    Energy Technology Data Exchange (ETDEWEB)

    Eldridge, John M.; Leemaster, Jacob Edward; Van Leeuwen, Brian P.

    2011-09-01

    Packet switched data communications networks that use distributed processing architectures have the potential to simplify the design and development of new, increasingly more sophisticated satellite payloads. In addition, the use of reconfigurable logic may reduce the amount of redundant hardware required in space-based applications without sacrificing reliability. These concepts were studied using software modeling and simulation, and the results are presented in this report. Models of the commercially available, packet switched data interconnect SpaceWire protocol were developed and used to create network simulations of data networks containing reconfigurable logic with traffic flows for timing system distribution.

  8. Next generation communications satellites: multiple access and network studies

    Science.gov (United States)

    Meadows, H. E.; Schwartz, M.; Stern, T. E.; Ganguly, S.; Kraimeche, B.; Matsuo, K.; Gopal, I.

    1982-01-01

    Efficient resource allocation and network design for satellite systems serving heterogeneous user populations with large numbers of small direct-to-user Earth stations are discussed. Focus is on TDMA systems involving a high degree of frequency reuse by means of satellite-switched multiple beams (SSMB) with varying degrees of onboard processing. Algorithms for the efficient utilization of the satellite resources were developed. The effect of skewed traffic, overlapping beams and batched arrivals in packet-switched SSMB systems, integration of stream and bursty traffic, and optimal circuit scheduling in SSMB systems: performance bounds and computational complexity are discussed.

  9. Need for, and financial feasibility of, satellite-aided land mobile communications

    Science.gov (United States)

    Castruccio, P. A.; Marantz, C. S.; Freibaum, J.

    Questions regarding the role of a mobile-satellite system in augmenting the terrestrial communications system are considered, and a market assessment study is discussed. Aspects of an investment analysis are examined, taking into account a three phase financial study of four postulated land Mobile Satellite Service (LMSS) systems, project profitability evaluation methods, risk analysis methods, financial projections, potential investor acceptance standards, and a risk analysis. It is concluded that a satellite augmented terrestrial mobile service appears to be economically and technically superior to a service depending exclusively on terrestrial systems. The interest in the Mobile Satellite Service is found to be worldwide, and the ground equipment market is potentially large.

  10. A review of satellite communication and propagation experiments for frequencies above 10 GHz

    Science.gov (United States)

    Setty, P. N. R.; Goessl, H.; Hounam, D.

    1983-02-01

    Satellite experiments aimed at improving communications in the higher frequency bands, especially above 10 GHz, are described. The basic types of transmission and measurement methods in these experiments are discussed, including beacon transmission, transmission from the ground with measurement on the ground.The satellite experiments considered include: ATS-5 millimeter wave propagation experiments; ATS-6 experiments at 13, 18, 20 and 30 GHz; Comstar experiments at 19 and 28 GHz; experiments with the CTS, ETS-II, SIRIO, CS, BSE, and OTS satellites. The payload parameters of the satellites are shown, and functional block diagrams for the ground terminals are presented.

  11. Satellite/Terrestrial Networks: End-to-End Communication Interoperability Quality of Service Experiments

    Science.gov (United States)

    Ivancic, William D.

    1998-01-01

    Various issues associated with satellite/terrestrial end-to-end communication interoperability are presented in viewgraph form. Specific topics include: 1) Quality of service; 2) ATM performance characteristics; 3) MPEG-2 transport stream mapping to AAL-5; 4) Observation and discussion of compressed video tests over ATM; 5) Digital video over satellites status; 6) Satellite link configurations; 7) MPEG-2 over ATM with binomial errors; 8) MPEG-2 over ATM channel characteristics; 8) MPEG-2 over ATM over emulated satellites; 9) MPEG-2 transport stream with errors; and a 10) Dual decoder test.

  12. Statistical Design Model (SDM) of power supply and communication subsystem's Satellite

    Science.gov (United States)

    Mirshams, Mehran; Zabihian, Ehsan; Zabihian, Ahmadreza

    In this paper, based on the fact that in designing the energy providing and communication subsystems for satellites, most approaches and relations are empirical and statistical, and also, considering the aerospace sciences and its relation with other engineering fields such as electrical engineering to be young, these are no analytic or one hundred percent proven empirical relations in many fields. Therefore, we consider the statistical design of this subsystem. The presented approach in this paper is entirely innovative and all parts of the energy providing and communication subsystems for the satellite are specified. In codifying this approach, the data of 602 satellites and some software programs such as SPSS have been used. In this approach, after proposing the design procedure, the total needed power for the satellite, the mass of the energy providing and communication subsystems , communication subsystem needed power, working band, type of antenna, number of transponders the material of solar array and finally the placement of these arrays on the satellite are designed. All these parts are designed based on the mission of the satellite and its weight class. This procedure increases the performance rate, avoids wasting energy, and reduces the costs. Keywords: database, Statistical model, the design procedure, power supply subsystem, communication subsystem

  13. Policy Issues in Planning for Distance Education Using a Domestic Communication Satellite.

    Science.gov (United States)

    Gough, J. Eric; And Others

    1981-01-01

    Considers important political and practical issues within the field of distance education raised by the decision for Australia to have its own communications satellite. The experiences of other countries are examined and the importance of communication policy and planning, educational needs-assessment, cost-effectiveness studies, resource…

  14. International Congress on Information and Communication Technology

    CERN Document Server

    Bhatt, Yogesh; Joshi, Amit; Mishra, Durgesh

    2016-01-01

    This volume contains 69 papers presented at ICICT 2015: International Congress on Information and Communication Technology. The conference was held during 9th and 10th October, 2015, Udaipur, India and organized by CSI Udaipur Chapter, Division IV, SIG-WNS, SIG-e-Agriculture in association with ACM Udaipur Professional Chapter, The Institution of Engineers (India), Udaipur Local Centre and Mining Engineers Association of India, Rajasthan Udaipur Chapter. This volume contains papers mainly focused on ICT for Managerial Applications, E-governance, IOT and e-Mining.

  15. Assistive Technologies for Communication and Information

    Directory of Open Access Journals (Sweden)

    Dusan Simsik

    2005-01-01

    Full Text Available Information and communication technologies (ICT affect all aspects of life, in the time of technical progress there are also special assistive devices developed that makes the daily life easier. The use of the ICT is rapidly becoming an essential part of social, educational and economic of sphere of European citizens’ life. There is a concern whether the products and services, that are available nowadays, are fully accessible to the public area, but also to elderly people and people with disabilities. The aim of this article is to acquire an outline about recent programmes of information society (Slovakia and EU, to revue the basic knowledge about the accessible ICT related to the equal opportunities for people with disabilities and to the social inclusion and describes the principles of accessible technologies (design for all, accessible webpages, electronic services. ICTs offer the enormous potential to maintain, improve quality of life, integration and independence.

  16. Information and Communication Technologies Innovations conference

    CERN Document Server

    Kocarev, Ljupco

    2012-01-01

    Information and Communication Technologies has enlarged its horizon and it is practiced under multidisciplinary contexts that introduce new challenges to theoretical and technical approaches. The most critical benefit of introducing new ICT technologies in our real world living are the new ways of working that the online world makes possible. Complexity, uncertainty and scaling issues of real world problems as well as natural phenomena in ecology, medicine and biology demanding ICT assistance create challenging application domains for artificial intelligence, decision support and intelligence systems, wireless sensor networks, pervasive and ubiquitous computing, multimedia information systems, data management systems, internet and web applications and services, computer networks, security and cryptography, distributed systems, GRID and cloud computing. This book offers a collection of papers presented at the Third International Conference on ICT Innovations held in September 2011, in Skopje, Macedonia. The co...

  17. Optimizing Satellite Communications With Adaptive and Phased Array Antennas

    Science.gov (United States)

    Ingram, Mary Ann; Romanofsky, Robert; Lee, Richard Q.; Miranda, Felix; Popovic, Zoya; Langley, John; Barott, William C.; Ahmed, M. Usman; Mandl, Dan

    2004-01-01

    A new adaptive antenna array architecture for low-earth-orbiting satellite ground stations is being investigated. These ground stations are intended to have no moving parts and could potentially be operated in populated areas, where terrestrial interference is likely. The architecture includes multiple, moderately directive phased arrays. The phased arrays, each steered in the approximate direction of the satellite, are adaptively combined to enhance the Signal-to-Noise and Interference-Ratio (SNIR) of the desired satellite. The size of each phased array is to be traded-off with the number of phased arrays, to optimize cost, while meeting a bit-error-rate threshold. Also, two phased array architectures are being prototyped: a spacefed lens array and a reflect-array. If two co-channel satellites are in the field of view of the phased arrays, then multi-user detection techniques may enable simultaneous demodulation of the satellite signals, also known as Space Division Multiple Access (SDMA). We report on Phase I of the project, in which fixed directional elements are adaptively combined in a prototype to demodulate the S-band downlink of the EO-1 satellite, which is part of the New Millennium Program at NASA.

  18. Design and Implementation of a Lunar Communications Satellite and Server for the 2012 SISO Smackdown

    Science.gov (United States)

    Bulgatz, Dennis; Heater, Daniel; O'Neal, Daniel A.; Norris, Bryan; Schricker, Bradley C.

    2012-01-01

    Last year, the Simulation Interoperability Standards Organization (SISO) inaugurated the now annual High Level Architecture (HLA) Smackdown at the Spring Simulation Interoperability Workshop (SIW). A primary objective of the Smackdown event is to provide college students with hands-on experience in the High Level Architecture (HLA). The University of Alabama in Huntsville (UAHuntsville) fielded teams in 2011 and 2012. Both the 2011 and 2012 smackdown scenarios were a lunar resupply mission. The 2012 UAHuntsville fielded four federates: a communications network Federate called Lunar Communications and Navigation Satellite Service (LCANServ) for sending and receiving messages, a Lunar Satellite Constellation (LCANSat) to put in place radios needed by the communications network for Line-Of-Sight communication calculations, and 3D graphical displays of the orbiting satellites and a 3D visualization of the lunar surface activities. This paper concentrates on the first two federates by describing the functions, algorithms, the modular FOM, experiences, lessons learned and recommendations for future Smackdown events.

  19. Research on Coal Exploration Technology Based on Satellite Remote Sensing

    Directory of Open Access Journals (Sweden)

    Dong Xiao

    2016-01-01

    Full Text Available Coal is the main source of energy. In China and Vietnam, coal resources are very rich, but the exploration level is relatively low. This is mainly caused by the complicated geological structure, the low efficiency, the related damage, and other bad situations. To this end, we need to make use of some advanced technologies to guarantee the resource exploration is implemented smoothly and orderly. Numerous studies show that remote sensing technology is an effective way in coal exploration and measurement. In this paper, we try to measure the distribution and reserves of open-air coal area through satellite imagery. The satellite picture of open-air coal mining region in Quang Ninh Province of Vietnam was collected as the experimental data. Firstly, the ENVI software is used to eliminate satellite imagery spectral interference. Then, the image classification model is established by the improved ELM algorithm. Finally, the effectiveness of the improved ELM algorithm is verified by using MATLAB simulations. The results show that the accuracies of the testing set reach 96.5%. And it reaches 83% of the image discernment precision compared with the same image from Google.

  20. 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.

  1. Commentary: how can technology help us understand the communication process?

    Science.gov (United States)

    Keyton, Joann

    2012-08-01

    In this commentary, the author reflects on the articles chosen for the special section on communications analysis. These articles problematize communication and raise an interesting set of questions for both human factors and communication scholars to ponder. In the end, both sets of scholars seek the same goal: How do we better examine communication to improve it? Problematizing communication requires scholars to challenge their fundamental assumptions about the phenomenon as well as to tease out the distinctions of methodological approaches typically used by both human factors and communication scholars. Human factors scholars tend to favor forms of communication in which technology or task roles control who can communicate and how. Communication scholars tend to favor contexts in which information flows more freely with fewer explicit restrictions. Creating opportunities to collaborate in research on the communication process may create the best understanding of technology that can better serve our understanding of communication.

  2. Advances in gallium arsenide monolithic microwave integrated-circuit technology for space communications systems

    Science.gov (United States)

    Bhasin, K. B.; Connolly, D. J.

    1986-01-01

    Future communications satellites are likely to use gallium arsenide (GaAs) monolithic microwave integrated-circuit (MMIC) technology in most, if not all, communications payload subsystems. Multiple-scanning-beam antenna systems are expected to use GaAs MMIC's to increase functional capability, to reduce volume, weight, and cost, and to greatly improve system reliability. RF and IF matrix switch technology based on GaAs MMIC's is also being developed for these reasons. MMIC technology, including gigabit-rate GaAs digital integrated circuits, offers substantial advantages in power consumption and weight over silicon technologies for high-throughput, on-board baseband processor systems. In this paper, current developments in GaAs MMIC technology are described, and the status and prospects of the technology are assessed.

  3. Control of satellite clusters in elliptic orbit with limited communication.

    Science.gov (United States)

    Chichka, David F; Belanger, Gene; Speyer, Jason L

    2004-05-01

    The cooperative control of satellite clusters in elliptical, low-Earth orbit is studied, with the goal of minimizing the necessary information passed among the individual satellites in the cluster. We investigate two possible control paradigms in this paper. The system is described using linearized equations of motion, allowing it to be expressed as a time-varying linear system. The control objective is to attain a required formation at a specified point along the orbit. A decentralized controller is used, in which each satellite maintains a local estimate of the overall state of the cluster. These estimates, along with any control information, are shared after any satellite executes a control action. The second paradigm is an extension of the first, in which state estimates are never shared, and only the control information is passed. In each case, less information being passed results in a higher computational burden on each satellite. Simulation results show cyclic errors, likely induced by higher-order terms in eccentricity and inclinations. The controller that shares state estimates performs much better than the controller that passes only control information.

  4. The principle of a navigation constellation composed of SIGSO communication satellites

    Institute of Scientific and Technical Information of China (English)

    Hai-Fu Ji; Li-Hua Ma; Guo-Xiang Ai; Hu-Li Shi

    2013-01-01

    The Chinese Area Positioning System (CAPS),a navigation system based on geostationary orbit (GEO) communication satellites,was developed in 2002 by astronomers at Chinese Academy of Sciences.Extensive positioning experiments of CAPS have been performed since 2005.On the basis of CAPS,this paper studies the principle of a navigation constellation composed of slightly inclined geostationary orbit (SIGSO) communication satellites.SIGSO satellites are derived from GEO satellites which are near the end of their operational life by inclined orbit operation.Considering the abundant frequency resources of SIGSO satellites,multi-frequency observations could be conducted to enhance the precision of pseudorange measurements and ameliorate the positioning performance.A constellation composed of two GEO satellites and four SIGSO satellites with an inclination of 5° can provide service to most of the territory of China with a maximum position dilution of precision (PDOP) over 24 h of less than 42.With synthetic utilization of the truncated precise code and a physical augmentation factor in four frequencies,the navigation system with this constellation is expected to obtain comparable positioning performance to that of the coarse acquisition code of the Global Positioning System (GPS).When the new method of code-carrier phase combinations is adopted,the system has the potential to possess commensurate accuracy with the precise code in GPS.Additionally,the copious frequency resources can also be used to develop new anti-interference techniques and integrate navigation and communication.

  5. Application of SAW technology in satellites for mobile services

    Science.gov (United States)

    Andreassen, O.; Viddal, V.; Galteland, J.

    1990-03-01

    Two surface acoustic wave (SAW) technologies for IF processing in a mobile satellite are discussed. The components and operations of the SAW filters method and the SAW filtering, routing, and beamforming concept are described. The capabilities of these two concepts are evaluated and compared. It is observed that the use of SAW filters is the more conventional and mature technology; it performs the channelizing function with a bank of SAW filters and routing of these channels by a switch matrix arrangement. The SAW filtering, routing, and beamforming concept is a more advanced technology that has the ability to give high resolution at low cost in volume and power; however, it has a high power consumption at large total processed bandwidth.

  6. Monte Carlo simulations of precise timekeeping in the Milstar communication satellite system

    Science.gov (United States)

    Camparo, James C.; Frueholz, R. P.

    1995-01-01

    The Milstar communications satellite system will provide secure antijam communication capabilities for DOD operations into the next century. In order to accomplish this task, the Milstar system will employ precise timekeeping on its satellites and at its ground control stations. The constellation will consist of four satellites in geosynchronous orbit, each carrying a set of four rubidium (Rb) atomic clocks. Several times a day, during normal operation, the Mission Control Element (MCE) will collect timing information from the constellation, and after several days use this information to update the time and frequency of the satellite clocks. The MCE will maintain precise time with a cesium (Cs) atomic clock, synchronized to UTC(USNO) via a GPS receiver. We have developed a Monte Carlo simulation of Milstar's space segment timekeeping. The simulation includes the effects of: uplink/downlink time transfer noise; satellite crosslink time transfer noise; satellite diurnal temperature variations; satellite and ground station atomic clock noise; and also quantization limits regarding satellite time and frequency corrections. The Monte Carlo simulation capability has proven to be an invaluable tool in assessing the performance characteristics of various timekeeping algorithms proposed for Milstar, and also in highlighting the timekeeping capabilities of the system. Here, we provide a brief overview of the basic Milstar timekeeping architecture as it is presently envisioned. We then describe the Monte Carlo simulation of space segment timekeeping, and provide examples of the simulation's efficacy in resolving timekeeping issues.

  7. Analysis of synchronous digital-modulation schemes for satellite communication

    Science.gov (United States)

    Takhar, G. S.; Gupta, S. C.

    1975-01-01

    The multipath communication channel for space communications is modeled as a multiplicative channel. This paper discusses the effects of multiplicative channel processes on the symbol error rate for quadrature modulation (QM) digital modulation schemes. An expression for the upper bound on the probability of error is derived and numerically evaluated. The results are compared with those obtained for additive channels.

  8. 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.

  9. Mass Communication: Technology Use and Instruction. ERIC Digest.

    Science.gov (United States)

    Brynildssen, Shawna

    This Digest reviews the literature on recent attempts to incorporate technology into the instruction of journalism and mass communication. It first discusses the four main categories of current technology use in journalism and mass communication: classroom instruction; online syllabi/materials; distance learning; and technological literacy. It…

  10. Computing, Information, and Communications Technology (CICT) Program Overview

    Science.gov (United States)

    VanDalsem, William R.

    2003-01-01

    The Computing, Information and Communications Technology (CICT) Program's goal is to enable NASA's Scientific Research, Space Exploration, and Aerospace Technology Missions with greater mission assurance, for less cost, with increased science return through the development and use of advanced computing, information and communication technologies

  11. Information and Communication Technologies in Social Work.

    Science.gov (United States)

    Perron, Brian E; Taylor, Harry O; Glass, Joseph E; Margerum-Leys, Jon

    2010-01-01

    Information and communication technologies (ICTs) are electronic tools used to convey, manipulate and store information. The exponential growth of Internet access and ICTs greatly influenced social, political, and economic processes in the United States, and worldwide. Regardless of the level of practice, ICTs will continue influencing the careers of social workers and the clients they serve. ICTs have received some attention in the social work literature and curriculum, but we argue that this level of attention is not adequate given their ubiquity, growth and influence, specifically as it relates to upholding social work ethics. Significant attention is needed to help ensure social workers are responsive to the technological changes in the health care system, including the health care infrastructure and use of technology among clients. Social workers also need ICT competencies in order to effectively lead different types of social change initiatives or collaborate with professionals of other disciplines who are using ICTs as part of existing strategies. This paper also identifies potential pitfalls and challenges with respect to the adoption of ICTs, with recommendations for advancing their use in practice, education, and research.

  12. Information and Communication Technologies in Social Work

    Directory of Open Access Journals (Sweden)

    Brian E. Perron

    2010-03-01

    Full Text Available Information and communication technologies (ICTs are electronic tools used to convey, manipulate and store information. The exponential growth of Internet access and ICTs greatly influenced social, political, and economic processes in the United States, and worldwide. Regardless of the level of practice, ICTs will continue influencing the careers of social workers and the clients they serve. ICTs have received some attention in the social work literature and curriculum, but we argue that this level of attention is not adequate given their ubiquity, growth and influence, specifically as it relates to upholding social work ethics. Significant attention is needed to help ensure social workers are responsive to the technological changes in the health care system, including the health care infrastructure and use of technology among clients. Social workers also need ICT competencies in order to effectively lead different types of social change initiatives or collaborate with professionals of other disciplines who are using ICTs as part of existing strategies. This paper also identifies potential pitfalls and challenges with respect to the adoption of ICTs, with recommendations for advancing their use in practice, education, and research.

  13. Low-Power Reflective Optical Communication System for Pico- and Nano-Satellites

    Science.gov (United States)

    Sinn, A.; Riel, T.; Deisl, F.; Saathof, R.; Schitter, G.

    2016-09-01

    Pico- and nano-satellites (PNS) are promising options for cost-effective and rapid deployable satellite systems. Due to their small size, the available power and therefore the transmittable data volume is limited. This paper proposes optical communication by means of reflected laser light using a modulating retro-reflector (MRR) for energy efficient optical communication with PNS. No laser source or beam steering assembly is necessary at the satellite, thus allowing a weight and energy efficient communication interface. Existing ground stations (GS) as used for satellite laser ranging (SLR) provide all equipment required for this system. By providing a link budget for communication to PNS in LEOs feasibility is investigated. It is shown that an affordable GS based on small telescopes with diameters below 0.3m in combination with commercial mounts enables the targeted application. A detailed analysis of LCD based MRRs is shown, denoting cost-efficient modulators for reflective optical communication. A data-rate of 2.5kbps at an input power of less than 80 mW is shown in a laboratory setup. Using a high performance sampling circuit and a laser power of only 1mW, a bit error ratio (BER) of below 10e-3 is achieved, successfully demonstrating reflective optical communication as an alternative to current RF based systems.

  14. 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...

  15. Effectiveness of information communication technology in rural insurance

    OpenAIRE

    Varadaraju Thamodaran; Mahalingam Ramesh

    2010-01-01

    Information and communications technologies are a device set of technological tools and resources used to communicate rural people about to disseminate awareness, create interest and to stimulate enroll intentions of insurance. It has enabled countries to leapfrog traditional modes of service delivery and make manifold improvements in process effectiveness and efficiency. Widespread adoption and application of information communication technology across the different fields of society and the...

  16. A satellite system for multimedia personal communications at Ka-band and beyond

    Science.gov (United States)

    Vatalaro, F.; Losquadro, G.

    1995-01-01

    The main characteristics of the satellite extremely high frequency (EHF) communication of multimedia mobile services (SECOMS) system are given and the results of the preliminary analysis are included. The SECOMS provides a first generation Ka band system with coverage over Western Europe, in order to satisfy business user needs of very large bandwidths and terminal mobility. The satellite system also provides a second generation EHF enhanced system with increased capacity and enlarged coverage, to serve all of Europe and the nearby countries.

  17. A Neural Network MLSE Receiver Based on Natural Gradient Descent: Application to Satellite Communications

    Directory of Open Access Journals (Sweden)

    Ibnkahla Mohamed

    2004-01-01

    Full Text Available The paper proposes a maximum likelihood sequence estimator (MLSE receiver for satellite communications. The satellite channel model is composed of a nonlinear traveling wave tube (TWT amplifier followed by a multipath propagation channel. The receiver is composed of a neural network channel estimator (NNCE and a Viterbi detector. The natural gradient (NG descent is used for training. Computer simulations show that the performance of our receiver is close to the ideal MLSE receiver in which the channel is perfectly known.

  18. A fault tolerant design for autonomous attitude control of the DSCS-III communication satellite

    Science.gov (United States)

    Matijevic, J.; Mettler, E.

    1983-01-01

    The first of a new series of satellites, which will provide the principal elements in the Defense Space Communications System (DSCS), was launched on Oct. 31, 1982. This satellite, DSCS-III, is part of a system which will consist of super-high frequency communications satellites in synchronous, equatorial orbits, continuously operating in four widely separate geographic regions. The DSCS-III is designed both to maintain critical communications in the presence of an electronic jamming threat and to survive nuclear radiation exposure. The results of the present investigation are to provide a basis for the design of a spacecraft tolerant of on-board failures, survivable against external threats, and capable of performing its mission autonomously for periods as long as six months.

  19. Developing satellite communications for public service: Prospects in four service areas

    Science.gov (United States)

    1977-01-01

    The Public Service Satellite Consortium evaluated prospects for satellite telecommunications in four areas of the public service: the U.S. health care system, elementary and secondary education, American libraries, and that sector of the public service which is concerned with the provision of continuing education to health professionals. Three important conclusions were reached. First, throughout the public service there are three recurring needs: improved access, cost containment, and maintenance of quality. Appropriate application of communication satellite systems could ameliorate each of these concerns. Second, there appears to be an enormous latent demand for data communication services throughout the public service. The potential demand in 1982 to support requirements in hospital administration, library services and other information-retrieval activities, equipment maintenance, and environmental monitoring may be in excess of $300 million a year. Third, administrative applications of data communication networks show particular promise, especially in rural areas.

  20. Optimization of orbital assignment and specification of service areas in satellite communications

    Science.gov (United States)

    Wang, Cou-Way; Levis, Curt A.; Buyukdura, O. Merih

    1987-01-01

    The mathematical nature of the orbital and frequency assignment problem for communications satellites is explored, and it is shown that choosing the correct permutations of the orbit locations and frequency assignments is an important step in arriving at values which satisfy the signal-quality requirements. Two methods are proposed to achieve better spectrum/orbit utilization. The first, called the delta S concept, leads to orbital assignment solutions via either mixed-integer or restricted basis entry linear programming techniques; the method guarantees good single-entry carrier-to-interference ratio results. In the second, a basis for specifying service areas is proposed for the Fixed Satellite Service. It is suggested that service areas should be specified according to the communications-demand density in conjunction with the delta S concept in order to enable the system planner to specify more satellites and provide more communications supply.