Sample records for satellite communications service

  1. A public service communications satellite user brochure

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The capabilities of a proposed communications satellite that would be devoted to experiments and demonstrations of various public services is described. A Public Service Communications Satellite study was undertaken at the NASA Goddard Space Flight Center (GSFC) to define the problems and opportunities of a renewed NASA role and the form such NASA involvement should take. The concept that has evolved has resulted from careful consideration of experiments that were already undertaken on existing satellites.

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

    ERIC Educational Resources Information Center

    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…

  3. Public Service Communications Satellite User Requirements Workshop

    NASA Technical Reports Server (NTRS)

    Wolff, E. A.

    1977-01-01

    Information on user requirements for public service communications was acquired to provide the basis of a study to determine the optimum satellite system to satisfy user requirements. The concept for such a system is described: Topics discussed included requirements for data and message services, elementary and secondary education, extension and continuing education, environmental communications, library services, medical education, medical services, public broadcasting, public safety, religious applications, state and local communications, and voluntary services. Information was also obtained on procedures to follow to make the transfer to commercial services.

  4. Communication satellite services for special purpose users

    NASA Technical Reports Server (NTRS)

    Wright, D. L.; Kiesling, J. D.

    1977-01-01

    The present study identifies potential satellite services, examines the technology necessary for efficient implementation of these services, and determines minimum service cost versus user network size. The generic satellite services evaluated comprise TV and radio distribution (for retransmission), video teleconferencing (interactive), audio/facsimile teleconferencing (interactive), multiplexed data/voice (point-to-point), and satellite-supported land mobile. Satellite costs are based on extrapolations from ongoing commercial satellite programs. Production methods, new technology, and effect of production quantities on present and future production costs are examined to provide information on earth station equipment cost versus the variable 'buy'. Six different launch vehicles from a Delta 2914 to a dedicated Shuttle and three frequency bands and both broadcast (no eclipse capability) and fixed service satellites are considered to assess the effect of satellite size on cost and performance. It is assumed that the user pays only for his prorata share of the space segment costs.

  5. Satellite communications for the next generation telecommunication services and networks

    NASA Technical Reports Server (NTRS)

    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. Satellite Communication.

    ERIC Educational Resources Information Center

    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…

  7. Planning satellite communication services and spectrum-orbit utilization

    NASA Technical Reports Server (NTRS)

    Sawitz, P. H.

    1982-01-01

    The relationship between approaches to planning satellite communication services and spectrum-orbit utilization is considered, with emphasis on the fixed-satellite and the broadcasting-satellite services. It is noted that there are several possible approaches to planning space services, differing principally in the rigidity with which technical parameters are prescribed, in the time for which a plan remains in force, and in the procedures adopted for implementation and modifications. With some planning approaches, spectrum-orbit utilization is fixed at the time the plan is made. Others provide for greater flexibility by making it possible to postpone some decisions on technical parameters. In addition, the two political questions of what is equitable access and how it can be guaranteed in practice play an important role.

  8. Emerging markets for satellite data communications in the public service

    NASA Technical Reports Server (NTRS)

    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.

  9. On the adaptability of LTE services in mobile satellite communications systems

    Microsoft Academic Search

    Xianghui Hu; Xiaohan Xia; Hongguang Lan; Jianjun Wu

    2012-01-01

    In this paper we mainly discuss the adaptability of LTE services in satellite communications systems. Four groups of LTE services are introduced, including the service aspects and transport requirements. Meanwhile several satellite systems are also listed in this paper. Based on these parameters and conditions, the adaptability of LTE services in mobile satellite communications systems is preliminarily discussed in terms

  10. Repeater in the sky. [public service communications satellite program

    NASA Technical Reports Server (NTRS)

    Cote, C. E.; Brown, J. P.

    1977-01-01

    The Public Service Communications Satellite (PSCS) program is intended to develop and demonstrate a space system aimed at stimulating future commercial markets in fixed and mobile applications. The services are envisioned for rural areas, regions beyond access to terrestrial systems, or for continuous cross-country applications. The system incorporates a UHF repeater for mobile voice and data experiments; 8 MHz of spectrum is specified for serving 70 channels. This paper describes the PSCS program and discusses some demonstration experiments. A future concept based on large structure multibeam antennas is also discussed.

  11. Provision of Electronic Healthcare Services via DVB-RCS Satellite Communication Technology

    E-print Network

    Vouyioukas, Demosthenes

    Provision of Electronic Healthcare Services via DVB-RCS Satellite Communication Technology V. Satellite broadband communications technologies, such as the Digital Video Broadcasting with Return Channel of Information and Communication Systems Engineering, University of the Aegean, Karlovasi 83200, Samos, Greece, e

  12. Satellite provided fixed communications services: A forecast of potential domestic demand through the year 2000: Volume 2: Main text

    NASA Technical Reports Server (NTRS)

    Kratochvil, D.; Bowyer, J.; Bhushan, C.; Steinnagel, K.; Kaushal, D.; Al-Kinani, G.

    1983-01-01

    Potential satellite-provided fixed communications services, baseline forecasts, net long haul forecasts, cost analysis, net addressable forecasts, capacity requirements, and satellite system market development are considered.

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

    NASA Technical Reports Server (NTRS)

    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.

  14. Public service communications satellite. [health, education, safety and information transfer applications

    NASA Technical Reports Server (NTRS)

    Wolff, E. A.

    1978-01-01

    Health, education, public safety, and information transfer applications of public service communications satellites are discussed with particular attention to the use of communications satellites to improve rural health delivery. Health-care communications requirements are summarized. The communications system concept involves small inexpensive stationary, portable, and moving ground terminals which will provide communications between any two points in the U.S. with both fixed and moving terminals on a continuous 24-hour basis. User requirements, wavebands, and privacy techniques are surveyed.

  15. Laser Communication Demonstration System (LSCS) and Future Mobile Satellite Services

    NASA Technical Reports Server (NTRS)

    Chen, C. -C.; Lesh, J. 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 (ISLs), laser communications technology can offer reduced mass , reduced power requirements, and increased channel bandwidths without regulatory restraint. This paper provides comparisons with radio systems and status of the program.

  16. Satellite communications experiment for the Ontario air ambulance service

    NASA Technical Reports Server (NTRS)

    Butterworth, John S.

    1988-01-01

    A satellite communications experiment was conducted to develop a reliable voice communications system between paramedics and doctors at certain larger medical centers. The experiment used INMARSAT's Atlantic Ocean Region satellite which provides coverage to the western border of Ontario. Forward downlink power from the satellite is in great demand, so two highly power-efficient modulation schemes were chosen for evaluation during the experiment. These were amplitude-companded single-sideband (ACSSB) and linear predictive coding in conjunction with DMSK modulation. Good performance with a signal to noise ratio of about 10 dB was demonstrated from many parts of the province with the evevation angle to the satellite ranging from five to twenty degrees and with the aircraft both in-flight and on the runway.

  17. Satellite applications to electric-utility communications needs. [land mobile satellite service

    NASA Technical Reports Server (NTRS)

    Horstein, M.; Barnett, R.

    1981-01-01

    Significant changes in the Nation's electric power systems are expected to result from the integration of new technology, possible during the next decade. Digital communications for monitor and control, exclusive of protective relaying, are expected to double or triple current traffic. A nationwide estimate of 13 Mb/s traffic is projected. Of this total, 8 Mb/s is attributed to the bulk-power system as it is now being operated (4 Mb/s). This traffic could be accommodated by current communications satellites using 3- to 4.5-m-diameter ground terminals costing $35,000 to $70,000 each. The remaining 5-Mb/s traffic is attributed to new technology concepts integrated into the distribution system. Such traffic is not compatible with current satellite technology because it requires small, low-cost ground terminals. Therefore, a high effective isotropic radiated power satellite, such as the one being planned by NASA for the Land Mobile Satellite Service, is required.

  18. Network Architecture and SONET Services in the NASA-ARPA Gigabit Satellite Network using NASA's Advanced Communications Technology Satellite (ACTS)

    Microsoft Academic Search

    Marcos A. Bergamo

    Abstract — The Gigabit Satellite Network, a project jointly sponsored by ARPA and NASA, will provide longhaul STS-3 (155.54 Mb\\/s) and STS-12 (622.08 Mb\\/s) point - to-point and point-to-multipoint full-duplex services over NASA's Advanced Communications Technology Satellite (ACTS). Data,multiplexing over the satellite will be accomplished using TDMA techniques coordinated with the switching and beam hopping facilities provided on-board the ACTS.

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

    NASA Technical Reports Server (NTRS)

    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.

  20. Use of communications. [satellite communication

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Progress in the field of satellite communications is reviewed, and useful services which may be provided by future satellite communications systems are considered. Recommendations are made with regard to mobile communications for use on land and at sea, position determination, mineral and energy exploration, the possibility of using electronic means to assist in main delivery, education and health-care experiments, and the use of satellite telecommunications to enhance the quality of life in rural areas by making available a full range of educational and entertainment programs. The needs of the amateur radio community are also considered.

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

    NASA Technical Reports Server (NTRS)

    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.

  2. The Role of Satellites in Personal Communication Services

    Microsoft Academic Search

    Fulvio Ananasso; Francesco Delli Priscoli

    1995-01-01

    This paper aims at providing a complete analysis of the issues relevant to satellite systems in the perspective of the third generation of mobile systems. The analysis considers, on the one hand, the possible satellite system evolutionary paths and, on the other hand, the satellite system requirements related to technological issues. As regards the satellite evolutionary paths, the paper provides

  3. Commercial communications satellite survivability

    NASA Astrophysics Data System (ADS)

    Bond, F. E.; Porter, R. L.

    The Government is considering the use of commercial communications satellite systems to support its national security and emergency preparedness needs. However, the vulnerabilities to hostile action inherent in commercial satellite systems could dramatically reduce their ability to provide essential services in emergency situations. Consequently, concern for the survivability of satellite, as well as other commercial telecommunications systems, has led to the establishment of the National Security Telecommunications Advisory Committee (NSTAC). Working in concert with the Government, the NSTAC, a Presidential Advisory Committee, has recommended a program to enhance the survivability of commercial communications satellite systems.

  4. Communication satellite studies applicable to mobile telephone services

    NASA Technical Reports Server (NTRS)

    Anderson, R. E.; Milton, R. T.; Brown, J. P.

    1979-01-01

    The potential use of satellites as extensions of existing terrestrial land mobile systems is discussed. Compatibility, particularly with cellular type systems, is considered. Sample technical and cost parameters and market assessments are also presented.

  5. Satellite spacing and frequency sharing for communication and broadcast services

    Microsoft Academic Search

    JOHN L. HULT; EDWARD E. REINHART

    1971-01-01

    Satellite relays complicate the problem of sharing a limited frequency spectrum that is in great demand. This paper reviews the problem and outlines a general approach for efficient use of orbits and spectrum. The protection of received signals, the equipment capabilities, and systems considerations pertinent to the problem are reviewed before systematically examining the principal direct and scatter modes of

  6. Telelibrary: Library Services via Satellite.

    ERIC Educational Resources Information Center

    Liu, Rosa

    1979-01-01

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

  7. Communications satellite systems capacity analysis

    NASA Technical Reports Server (NTRS)

    Browne, L.; Hines, T.; Tunstall, B.

    1982-01-01

    Analog and digital modulation techniques are compared with regard to efficient use of the geostationary orbit by communications satellites. Included is the definition of the baseline systems (both space and ground segments), determination of interference susceptibility, calculation of orbit spacing, and evaluation of relative costs. It is assumed that voice or TV is communicated at 14/11 GHz using either FM or QPSK modulation. Both the Fixed-Satellite Service and the Broadcasting-Satellite Service are considered. For most of the cases examined the digital approach requires a satellite spacing less than or equal to that required by the analog approach.

  8. Equalizers for communications satellites

    E-print Network

    Fay, Leon

    2008-01-01

    This thesis investigates equalization for advanced protected satellite communications systems in development at MIT Lincoln Laboratory. Equalizers facilitate high data rate communication by correcting dispersion in the ...

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

    Microsoft Academic Search

    Phil Cragg; William E. Brockman

    2006-01-01

    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

  10. Advanced Communications Technology Satellite (ACTS)

    NASA Technical Reports Server (NTRS)

    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.

  11. IRIDIUM(R) aeronautical satellite communications

    Microsoft Academic Search

    P. W. Lemme; S. M. Glenister; A. W. Miller

    1998-01-01

    The ever-increasing demand to stay in touch, to be able to communicate anywhere and anytime, has created a market for Low Earth Orbit (LEG) satellite communications services such as the Iridium System. The Iridium satellite communications network is being developed to support the needs of the passenger, the cabin crew and the flight crew. Iridium Communications LLC owns a network

  12. Experiment In Aeronautical-Mobile/Satellite Communication

    NASA Technical Reports Server (NTRS)

    Jedrey, Thomas C.; Lay, Norman E.; Dessouky, Khaled

    1992-01-01

    Report describes study of performance of digital mobile/satellite communication terminals of advanced design intended for use in ground stations and airplanes in aeronautical-mobile service. Study was collaboration of NASA, Federal Aviation Administration (FAA), Communications Satellite Corp. (COMSAT), and International Maritime Satellite System (INMARSAT).

  13. Satellite-Based Educational Services. Technical Memorandum.

    ERIC Educational Resources Information Center

    Operations Research, Inc., Silver Spring, MD.

    This memorandum contains engineering information relevant to the use of communication satellites for educational purposes. Information is provided for ground terminals as well as satellites. Satellite related issues addressed include: (1) expected life of service of various satellites, (2) constraints on the availability of the satellites, (3)…

  14. Iridium(R) aeronautical satellite communications

    Microsoft Academic Search

    P. W. Lemme; S. M. Glenister; A. W. Miller

    1999-01-01

    The ever-increasing demand to stay in touch, to be able to communicate anywhere and anytime, has created a market for low Earth orbit (LEO) satellite communications services such as the Iridium system. The Iridium satellite communications network is being developed to support the needs of the passenger, the cabin crew and the flight crew for: aeronautical public correspondence (APC); aeronautical

  15. Domestic Communications Satellites.

    ERIC Educational Resources Information Center

    Network Project Notebook, 1972

    1972-01-01

    The June, 1972 Federal Communications Commission's (FCC) decision allowed an "open skies" policy in regard to domestic communication satellites and raised Liberal opposition to a situation where exclusive and unchecked communications power is now in the hands of private entrepreneurs, primarily the big Defense Department oriented aerospace…

  16. Advanced Communications Technology Satellite (ACTS)

    NASA Technical Reports Server (NTRS)

    Plecity, Mark S.; Nall, Mark E.

    1991-01-01

    The NASA Advanced Communications Technology Satellite (ACTS) provides high risk technologies having the potential to dramatically enhance the capabilities of the satellite communications industry. This experimental satellite, which will be launched by NASA in 1993, will furnish the technology necessary for providing a range of services. Utilizing the ACTS very-high-gain-hopping spot-beam antennas with on-board routing and processing, Very Small Aperture Terminal (VSAT) digital networks which provide on-demand, full-mesh-convectivity 1.544-MBPS services with only a single hop can be established. The high-gain spot-beam antenna at Ka-band permits wide area, flexible networks providing high data rate services between modest-size earth terminals.

  17. Satellite communications and the information decade - An overview

    NASA Astrophysics Data System (ADS)

    Cuccia, C. L.

    1982-01-01

    The paper examines how the information era will utilize satellite communications and digital communication to initiate an era of new users and new satellite services to meet the needs of a highly competitive telecommunications market. Particular consideration is given to microwaves and the development of the chip; communication satellites and information flow; the communication satellite as an information path; the Ku-band direct broadcast satellite; and 30/20 GHz communication satellites.

  18. Domestic Communication Satellites

    ERIC Educational Resources Information Center

    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)

  19. Communication satellite antennas

    Microsoft Academic Search

    LEON J. RICARDI

    1977-01-01

    During the previous two decades, communication satellites have developed from the pioneering Telstar to the highly sophisticated ATS-6. Concurrrently, the spacecraft antennas have developed from a low-gain \\

  20. System considerations, projected requirements and applications for aeronautical mobile satellite communications for air traffic services

    NASA Technical Reports Server (NTRS)

    Mcdonald, K. D.; Miller, C. M.; Scales, W. C.; Dement, D. K.

    1990-01-01

    The projected application and requirements in the near term (to 1995) and far term (to 2010) for aeronautical mobile services supporting air traffic control operations are addressed. The implications of these requirements on spectrum needs, and the resulting effects on the satellite design and operation are discussed. The U.S. is working with international standards and regulatory organizations to develop the necessary aviation standards, signalling protocols, and implementation methods. In the provision of aeronautical safety services, a number of critical issues were identified, including system reliability and availability, access time, channel restoration time, interoperability, pre-emption techniques, and the system network interfaces. Means for accomplishing these critical services in the aeronautical mobile satellite service (AMSS), and the various activities relating to the future provision of aeronautical safety services are addressed.

  1. Signals from Communications Satellites.

    ERIC Educational Resources Information Center

    Thomsen, Volker

    1996-01-01

    Discusses the Doppler effect for relative motion between a source of waves and an observer and the orbital dynamics of communications satellites. Presents preliminary calculations of the satellite's altitude and linear velocity using only the concepts of the Doppler shift and the mechanics of motion in a circular path. (JRH)

  2. Mobile satellite communications

    Microsoft Academic Search

    W. W. Wu; E. F. Miller; W. L. Pritchard; R. L. Pickholtz

    1994-01-01

    The paper presents an up-to-date overview as well as new results on mobile satellite communications. Specifically, the following subjects are addressed: worldwide activities; satellite orbits; multiple access techniques; Novstar global positioning system; economic and regulatory issues; future trends. Some of these technical and nontechnical subjects appeal disjoint, but they are unique and significant among the many facets, which effect the

  3. Amateur Radio Satellite Communications.

    ERIC Educational Resources Information Center

    Koch, David P.

    The Amateur Radio Satellite Communications project had, as its goal, the assembly of an amateur radio satellite station in a high school physics classroom. Specific objectives were to provide: (1) a special source of interest as a motivator for attracting students and building public relations; (2) a center of interest as a motivator for the study…

  4. Efficient Packet Satellite Communications

    Microsoft Academic Search

    JOSEPH K. DEROSA; LAWRENCE H. OZAROW; LESLIE N. WEINER

    1979-01-01

    This paper gives an extensive analysis of a Packet satellite (PACSAT) communications system that uses a digital processing satellite in a packet data network. It is shown that multiple uplinks coupled with on-board switching and storage can provide significant gains in throughput, efficiency, and margin against instability. Design tradeoffs are presented and the theoretical results are verified by extensive computer

  5. Satellite Communications Using Commercial Protocols

    NASA Technical Reports Server (NTRS)

    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.

  6. Experimental Satellite Quantum Communications

    E-print Network

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

    2014-06-16

    Quantum Communications on planetary scale require complementary channels including ground and satellite links. The former have progressed up to commercial stage using fiber-cables, while for satellite links, the absence of terminals in orbit has impaired theirs development. However, the demonstration of the feasibility of such links is crucial for designing space payloads and to eventually enable the realization of protocols such as quantum-key-distribution (QKD) and quantum teleportation along satellite-to-ground or intersatellite links. We demonstrated the faithful transmission of qubits from space to ground by exploiting satellite corner cube retroreflectors acting as transmitter in orbit, obtaining a low error rate suitable for QKD. We also propose a two-way QKD protocol exploiting modulated retroreflectors that necessitates a minimal payload on satellite, thus facilitating the expansion of Space Quantum Communications.

  7. Laser satellite communications

    Microsoft Academic Search

    Morris Katzman

    1987-01-01

    The basic principles of laser communications and the designing of laser systems are analyzed. Consideration is given to the link equation, the transmitter terminal, antennas, the optical detector, optical modulation formats, deriving error rate data, and signal requirements for acquisition and tracking. The characteristics of some semiconductor laser sources used for satellite communications are examined. The functions of the optical

  8. Satellite communications system 'Tyulpan'

    NASA Astrophysics Data System (ADS)

    Tchuyan, R. K.; Tarasov, E. V.; Belousov, A. P.; Balyk, V. M.; Kovtunenko, V. M.; Morozov, V. A.; Andreev, V. A.; v'yunenko, K. A.

    1993-10-01

    A concept of the satellite communication system called 'Tyulpan' (because or its tulip-resembling shape) is considered. This conception envisages the use of six satellites-retranslators installed on high-latitude elliptic orbits. Such a system can provide the communication for mean- and high-latitude region of Europe, Asia, and America. For the communication, super small ground stations of 0.4 m in diameter can be used. In the development of system conception, the already existing technical solutions and possibility of conversion or existing installations of military destination were taken into account. Therefore, the system considered can be realized at the earliest possible date.

  9. Satellite Services Workshop, Volume 1

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Key issues associated with the orbital servicing of satellites are examined including servicing spacecraft and equipment, servicing operations, economics, satellite design, docking and berthing, and fluid management.

  10. Business use of satellite communications

    NASA Astrophysics Data System (ADS)

    Edelson, B. I.; Cooper, R. S.

    1982-02-01

    The development, systems technology, and future applications of digital transmission systems for business use of satellite systems are explored. Intelsat currently has 22 satellites in space, applied mostly to data, telephone, and television transmission. An all digital communications network called the Integrated Services Digital Network is replacing the former, analog, systems with wideband digital transmission for voice, data, video, and industrial control information, with domestic satellites serving as the central node of transmissions in a service area. The digital systems are faster than the analog systems, and the U.S. Postal Service is developing an electronic mail system with six other countries. Various magazines are now teleprinted in various locations from broadcasts from a central source, and chain stores are employing data transmission for centralized management, inventory, and procurement.

  11. Satellite communication system integrated into terrestrial ISDN

    Microsoft Academic Search

    TORU OTSU; KAZUHIRO NAGAYAMA; AKIRA KUROKAWA; HIROSHI NAKASHIMA; MASAHIRO UMEHIRA

    2000-01-01

    This paper presents an advanced satellite communication system named DYANET II. This system uses satellite channels as subscriber lines for ISDN customers as well as trunk circuits for overflow traffic. The system can offer the same ISDN services to satellite customers as those available to terrestrial subscribers in terms of numbering, signaling, and charging systems as well as user-network interfaces.

  12. Domestic satellite communications overview

    NASA Astrophysics Data System (ADS)

    Nickelson, R. L.

    1984-09-01

    The current status and future planning of satellite systems for intranational communication are examined in a summary of presentations given at the CCIR international seminar on domestic satellite communications held in Shanghai in October 1983. Topics discussed include operational and planned systems in Australia, Japan, the U.S., India, China, France, Brazil, Italy, Thailand, and the European region; development and planning by NASA and Intelsat; systems for rural areas or light traffic; modulation and multiple access; antennas, propagation, and interference; geostationary orbits; and economics, planning, and implementation.

  13. Land-mobile satellite communication system

    NASA Technical Reports Server (NTRS)

    Yan, Tsun-Yee (Inventor); Rafferty, William (Inventor); Dessouky, Khaled I. (Inventor); Wang, Charles C. (Inventor); Cheng, Unjeng (Inventor)

    1993-01-01

    A satellite communications system includes an orbiting communications satellite for relaying communications to and from a plurality of ground stations, and a network management center for making connections via the satellite between the ground stations in response to connection requests received via the satellite from the ground stations, the network management center being configured to provide both open-end service and closed-end service. The network management center of one embodiment is configured to provides both types of service according to a predefined channel access protocol that enables the ground stations to request the type of service desired. The channel access protocol may be configured to adaptively allocate channels to open-end service and closed-end service according to changes in the traffic pattern and include a free-access tree algorithm that coordinates collision resolution among the ground stations.

  14. Satellite Services Rate Schedule Effective March 26, 2014

    E-print Network

    Acton, Scott

    Satellite Services Rate Schedule Effective March 26, 2014 SCPS offers satellite communications Satellite Services email satellite@virginia.edu or call 434-982-5268. Services UVa/State Regular* UVa Studio to Vyvx $335 $500 $400 $600 IFB & PL $15 $20 $20 $30 Tape Playback $65 $100 $85 $125 Satellite

  15. SLCSAT (Submarine Laser Communication Satellite) communication system design study

    Microsoft Academic Search

    S. L. Bernstein; R. S. Bondurant; E. A. Bucher; V. W. Chan; F. G. Walther

    1989-01-01

    This report summarizes the results of a Lincoln Laboratory study of issues affecting Submarine Laser Communication Satellite (SLCSAT) implementation. The study compares alternative SLCSAT downlink implementations using semiconductor and solid-state lasers in terms of the satellite transmitter power required to provide a given level of communication service. Signal coding is applied to increase transmitter design flexibility by accommodating a wider

  16. Laser satellite communication network-vibration effect and possible solutions

    Microsoft Academic Search

    SHLOMI ARNON; N. S. Kopeika

    1997-01-01

    A number of serious consortiums develop satellite communication networks. The objective of these communication projects is to service personal communication users almost everywhere on Earth. The intersatellite links in those projects use microwave radiation as the carrier. Free-space optical communication between satellites networked together can make possible high-speed communication between different places on Earth. Some advantages of an optical communication

  17. Low Earth orbit communications satellite

    NASA Technical Reports Server (NTRS)

    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.

  18. AERONAUTICAL BROADBAND COMMUNICATIONS VIA SATELLITE

    Microsoft Academic Search

    M. Werner; M. Holzbock

    The paper discusses various aspects of aeronautical broadband satellite communications (AirCom). A range of applications and services is identified and categorized into the scenarios of in-flight entertainment, in-flight office, telemedicine, flight security, and flight logistics & maintenance. A number of operational and planned AirCom systems are presented. A structured overview of key issues and respective steps for the system design

  19. Business Use of Satellite Communications.

    ERIC Educational Resources Information Center

    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)

  20. Communication satellite processing repeaters

    Microsoft Academic Search

    R. Y. Huang; P. Hooten

    1971-01-01

    Two kinds of processing repeaters which may find application on communication satellites in the near future are described. The type I repeater allows access only if the transmitted signal contains a predetermined code structure. This serves three purposes: first, unauthorized users are excluded, second, co-channel interfering signals are not retransmitted on the downlink, so as not to waste a portion

  1. Coding for Satellite Communication

    Microsoft Academic Search

    William W. Wu; David Haccoun; Robert Peile; Yasuo Hirata

    1987-01-01

    This paper discusses a number of coding techniques for future satellite communication; they include Reed-Solomon error decoding for message blocks, probabilistic decoding techniques for punctured convolutional codes, and planar Euclidean geometry difference set codes for random multiple access applications. The provision of code concatenation, helical interleaving, and simulation results of new punctured convolutional codes are included. A number of coded

  2. Future communications satellite applications

    NASA Technical Reports Server (NTRS)

    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.

  3. Advanced Communications Technology Satellite (ACTS)

    Microsoft Academic Search

    R. T. Gedney; R. J. Schertler

    1989-01-01

    The authors provide an overview of the NASA Advanced Communications Technology Satellite (ACTS) and discuss the value of the technology for future communication systems. The high-risk technologies selected for ACTS were those having the potential to dramatically enhance the capabilities of the satellite communications industry. This experimental satellite, which is scheduled to be launched in 1992, will furnish very small

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

    NASA Technical Reports Server (NTRS)

    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.

  5. Manual of satellite communications

    NASA Astrophysics Data System (ADS)

    Fthenakis, E.

    The design and operation of satellite communications systems (SCSs) are examined in an introductory text for graduate engineering students. The history of SCSs during the period 1962-1982 is traced with an emphasis on US commercial ventures, and the overall function and economics of SCSs is reviewed. Individual chapters are devoted to orbits, launch sequences, and on-station positioning; spacecraft systems; communications payloads; earth stations and terrestrial links; uplinks and downlinks; linear systems and signals; random processes and noise; analog modulation; digital communicatins; coding and forward error detection; transmission impairments; and networks and systems (multiplexing, FDMA, TDMA, CDMA, and variable-access demand asignment. Graphs showing the apparent motion of the sun with respect to an earth satellite; summaries of Fourier analysis, Hilbert transforms, vector and matrix representations; and a table listing the characteristics of major SCSs are included in appendices.

  6. Survey: National Environmental Satellite Service

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The national Environmental Satellite Service (NESS) receives data at periodic intervals from satellites of the Synchronous Meteorological Satellite/Geostationary Operational Environmental Satellite series and from the Improved TIROS (Television Infrared Observational Satellite) Operational Satellite. Within the conterminous United States, direct readout and processed products are distributed to users over facsimile networks from a central processing and data distribution facility. In addition, the NESS Satellite Field Stations analyze, interpret, and distribute processed geostationary satellite products to regional weather service activities.

  7. Channel characterisation for spread spectrum satellite communications

    Microsoft Academic Search

    Axel Jahn; Hermann Bischl; G. Heiss

    1996-01-01

    The paper examines the characteristics of satellite propagation channels for spread spectrum communications. Based on measurement campaigns at L-band, the signal bandwidth is determined when the channel becomes frequency-selective. A wideband channel model for land mobile satellite (LMS) services is presented which characterises the time-varying transmission channel between a satellite and a mobile user terminal. The parameters of the model

  8. NASA's program in communication satellites

    NASA Technical Reports Server (NTRS)

    Sivo, J. N.

    1980-01-01

    It is noted that NASA is currently proceeding with a revitalized R&D program aimed at the development and demonstration of advanced communication satellite system concepts and the related enabling technologies. The paper reviews the important elements of this program thrust, the approach NASA is taking to assure proper involvement of both the system supplier industry and the service supplier industry and the specific technology focus in the near term. Finally, highlights of the current NASA and industry activities related to opening up the 30/20 GHz frequency band for both commercial and military use are presented.

  9. Corporate strategies for satellite communications

    NASA Astrophysics Data System (ADS)

    Birch, David G. W.; Buck, S. Peter

    1991-10-01

    Terrestrial and satellite broadcast communications technologies, while clearly providing tremendous benefits in many market sectors, present something of a challenge to the strategic planning bodies in most organizations. This is because there is no existing analog for the services in the organizations' telecommunications networks. The marketplace is therefore a confusing place for such organizations swamped as it is with competing service providers, technologies, and services, and their telecommunications strategies cannot cope with the opportunities because they have been founded on the exploitation of point to point connections. A mechanism for creating and bounding strategies which combines the rigor of structured analysis with a comprehensive categorization of strategic directions which has been successfully used to generate new paneuropean telecommunications strategies is presented.

  10. Optical satellite communications in Europe

    Microsoft Academic Search

    Zoran Sodnik; Hanspeter Lutz; Bernhard Furch; Rolf Meyer

    2010-01-01

    This paper describes optical satellite communication activities based on technology developments, which started in Europe more than 30 years ago and led in 2001 to the world-first optical inter-satellite communication link experiment (SILEX). SILEX proved that optical communication technologies can be reliably mastered in space and in 2006 the Japanese Space Agency (JAXA) joined the optical inter-satellite experiment from their

  11. Mobile satellite service in the United States

    NASA Technical Reports Server (NTRS)

    Agnew, Carson E.; Bhagat, Jai; Hopper, Edwin A.; Kiesling, John D.; Exner, Michael L.; Melillo, Lawrence; Noreen, Gary K.; Parrott, Billy J.

    1988-01-01

    Mobile satellite service (MSS) has been under development in the United States for more than two decades. The service will soon be provided on a commercial basis by a consortium of eight U.S. companies called the American Mobile Satellite Consortium (AMSC). AMSC will build a three-satellite MSS system that will offer superior performance, reliability and cost effectiveness for organizations requiring mobile communications across the U.S. The development and operation of MSS in North America is being coordinated with Telesat Canada and Mexico. AMSC expects NASA to provide launch services in exchange for capacity on the first AMSC satellite for MSAT-X activities and for government demonstrations.

  12. Operating Frequencies for Educational Satellite Services.

    ERIC Educational Resources Information Center

    Singh, Jai P.

    Part of a continuing study of application of communication satellites for helping to meet educational needs, this memorandum discusses operating frequencies for educational satellite services. Each of the factors affecting choice of transmission frequencies is identified and discussed in a separate section. Included among these factors are…

  13. Europe's communications satellite system takes shape

    NASA Astrophysics Data System (ADS)

    1981-10-01

    Europe's current satellite system and impending additions are discussed, with emphasis on improvements in Europe's communications service. The first transponder for the ECS has been recently delivered from AEG-Telefunken to the French space flight center for the assembly of the AEG solar generator and integration into the satellite body. The communications satellite will be stationed at a height of 36,000 km in the spring of 1982, which should result in 24,500 new telephone connections and two new television channels for the people of Europe.

  14. Fault management on communications satellites

    Microsoft Academic Search

    R. D. Coblin

    1999-01-01

    There is a military communications (MILCOM) satellite system which is designed to provide communications for military users. To meet this mission, a key function to be performed is autonomous fault management of the MILCOM system which includes a constellation of satellites and a collection of dedicated ground control stations. The impact of the MILCOM fault management system to the space,

  15. Advanced satellite communication system

    NASA Technical Reports Server (NTRS)

    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.

  16. Satellites extend communications to remote areas

    SciTech Connect

    Amey, S. [Discovery Communications, Crofton, MD (United States)

    1996-10-01

    The advent of new communications technologies has played a lead role in building the global village, enabling companies to conduct international business more cost-efficiently, especially when an increasing number of companies are exploring remote parts of the world with minimal or non-existent infrastructure. Both voice and data communications have become significant challenges in these undeveloped areas. To solve this problem, oil and gas companies have begun relying on satellite communications. Recent advances in technology and new satellite systems being developed will enable companies to select from a broader range of services and price options.

  17. Global trade in satellites and launch services

    NASA Astrophysics Data System (ADS)

    Hearing before the Subcommittee on Space of the Committee on Science, Space, and Technology of the House of Representatives is presented. Written testimony, submittals for the record, and responses to written questions are included. Topics concerning the global trade in satellites and launch services include foreign competition, the China and Russia trade agreements, Commerce licensing on international sales and export, trade control, technology transfer, satellite communications and the economy, satellites and the global information infrastructure, commercial space revenues, and enforcement of trade policies.

  18. Antennas for mobile satellite communications

    NASA Technical Reports Server (NTRS)

    Huang, John

    1991-01-01

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

  19. A design of 30/20 GHz flight communications experiment for NASA. [satellite and earth segments for high data rate commercial service

    NASA Technical Reports Server (NTRS)

    Kawamoto, Y.

    1982-01-01

    The objective of the 30/20 GHz Flight Experiment System is to develop the required technology and to experiment with the communication technique for an operational communication satellite system. The system uses polarization, spatial, and frequency isolations to maximize the spectrum utilization. The key spacecraft technologies required for the concept are the scan beam antenna, the baseband processor, the IF switch matrix, TWTA, SSPA, and LNA. The spacecraft communication payload information will be telemetered and monitored closely so that these technologies and performances can be verified. Two types of services, a trunk service and a customer premise service, are demonstrated in the system. Many experiments associated with these services, such as synchronization, demand assignment, link control, and network control will be performed to provide important information on the operational aspect of the system.

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

    NASA Technical Reports Server (NTRS)

    Pepin, Gerard R.

    1992-01-01

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

  1. Power versus stabilization for laser satellite communication.

    PubMed

    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. PMID:18319913

  2. Adapting commercial satellites to military communication needs

    Microsoft Academic Search

    L. B. Jocic; S. A. Hovanessian; J. K. Kreng; M. D. Schultz

    1996-01-01

    Increased reliance on commercial equipment by the military is necessary in today's defense environment. Potential cost reductions due to leveraging off the commercial satellite communication (satcom) base are a strong factor in planning for future military satcom (milsatcom) systems. Commercial satcom services are being extended to the “Ka” frequency band (30\\/20 GHz) to accommodate increasing demands for higher throughput and

  3. Multiservice on-board switching for mobile satellite communications

    Microsoft Academic Search

    L. Bella

    1988-01-01

    Future satellites for mobile communications will be required to interface ground ISDN (integrated services digital network) and to provide services and performances comparable with those offered by cellular radio networks. Onboard processing is a key technique to satisfy these requirements and can provide efficient integration with fixed satellite services. The European Space Agency (ESA) has started the development of a

  4. Potential markets for advanced satellite communications

    NASA Technical Reports Server (NTRS)

    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.

  5. Traffic assignment in communication satellites

    Microsoft Academic Search

    E. Balas; P. R. Landweer

    1983-01-01

    A high capacity communication satellite interconnects scores of ground stations simultaneously. Under the Satellite-Switched\\/Time Division Multiple Access (SS\\/TDMA) system, each channel of the satellite is allocated to a pair of ground stations for a certain time period, after which the whole set of allocations (called a switch) is changed simultaneously. The problem the authors is to minimize the time length

  6. Remote operation of communications satellites

    NASA Astrophysics Data System (ADS)

    Garner, J. T.; Sturcbecher, J.; Jones, M.

    The role of ESA's Operations and Control Centre (OCC) in remote operation of communications satellites is discussed. The performance of OCC in this regard prior to launch is described, and developments in these operations are reviewed. The future prospects of remote operation of satellites are addressed.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Technical Reports Server (NTRS)

    Pepin, Gerard R.

    1992-01-01

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

  9. NOAA Satellite and Information Service

    NSDL National Science Digital Library

    "The Satellite Services Division of the National Environmental Satellite, Data, and Information Service (NESDIS) provides real time access to satellite data and products for the public and government." Users can locate Hazard Mapping System (HMS) Fire Analysis, real-time satellite fire monitoring, Web-based GIS fire analysis, and additional fire products. The OSEI (Operational Significant Event Imagery) link supplies archived and current images of flood events, severe weather, tropical cyclones, and other significant environmental events. Researchers can find technical information on the satellites. Individuals can also find bulletins, advisories, text data, and images of precipitation, snow and ice, volcanic activity, winds, and tropical weather.

  10. US weather satellites and services

    NASA Astrophysics Data System (ADS)

    The weather satellites and services of the National Weather Service of the National Oceanic and Atmospheric Administration are discussed. The economy and public safety of Washington State, monitoring of the extreme weather conditions around Mount St. Helens and search and rescue satellites are included.

  11. Communications satellites versus fiber optics

    NASA Astrophysics Data System (ADS)

    Goldman, A. M., Jr.

    Examples of the interfaces encountered in the provision of intercity, long-distance service in the U.S. are examined, and a comparison is conducted of the costs of the Intercity, Long-Distance portion of a single voice circuit derived from either fixed satellite trunking service or fiber optic bulk capacity. It is estimated that by the end of 1988, fiber optic should span the nation connecting New York and Washington with Los Angeles and San Francisco. It is shown that once fiber connects a given pair of cities, it becomes the least costly transmission medium, especially compared to fixed satellite service. Attention is given to equivalent transmission capacities, six providers of fiber optic capacity, a total satellite capacity comparison, an economic lifetime comparison, satellite and fiber optic network maps, satellite city-pair distance and cost matrices, and fiber optic city-pair distance matrices. It is pointed out that certain future CONUS satellite service applications will be inherently invulnerable to terrestrial fiber optics serving fixed routes.

  12. Communications Satellites Using Arrays

    Microsoft Academic Search

    R. C. Hansen

    1961-01-01

    Passive reflectors require large ground antennas and powers but permit use of unstabilized reflectors. Active systems, on the other hand, offer attractive performance through high directivity antennas but generally require stabilized vehicles. Further, the reliability of a satellite repeater amplifier is a critical factor. Automatic angle return arrays are investigated for both passive and active systems. These arrays, called Van

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  14. An experimental model design of bidirectional communication mobile terminal for Ku-band satellite-internet services

    Microsoft Academic Search

    Ung Hee Park; Young Bae Jung; Jae Seung Yun; Soon Ik Jeon; Chang Ju Kim

    2003-01-01

    ETRI has developed an active phased array antenna as an experimental model for use in the mobile satellite-internet services in Ku-band. In this paper, RF transmitter of this phased array antenna system is described, which is one of key components. This RF transmitter consists of TRx duplexer, 1:10 power divider and ten channels including Tx active channel block and antenna.

  15. Satellite Communications: Hopes and Fears

    ERIC Educational Resources Information Center

    Sirkin, Abraham M.

    1978-01-01

    The potentials of space communication, including the prospects and problems of direct broadcast TV satellites, are examined. Considered are future visions, internal and international goals, economic factors, political constraints, prior consent, U.S. and U.N. positions, and free flow of information. (LBH)

  16. Satellite communications and broadcasting; Proceedings of the International Conference, London, England, Dec. 2-4, 1986

    NASA Astrophysics Data System (ADS)

    Papers are presented on private satellite networks in the U.S.; the competitive market for international satellite services; private satellite networks in Europe; and various applications for satellites, in particular data broadcasting and business communications. Topics discussed include the worldwide regulation of satellite broadcasting and communications; the capabilities of Eutelsat II; trends in satellite technology; and the role of insurance in space industries. Consideration is given to the use of the ASTRA satellite for TV broadcasting; the services provided by Intelsat; the evolution of American television due to satellites; consumer satellite Television Receive Only marketing in Europe; and satellite programming.

  17. Low earth orbit satellite based communication systems — Research opportunities

    Microsoft Academic Search

    Bezalel Gavish

    1997-01-01

    Telecommunication systems are undergoing revolutionary changes that are transforming society, changing the way in which industrial and service organizations operate, and are having a profound effect on the daily life of individuals. Low earth orbit satellite (LEOS) based communication systems are a new and exciting endeavor in reshaping the global communication network and the services that it provides. Huge investments

  18. Satellite communications systems and technology. Volume 1: Analytical chapters

    NASA Technical Reports Server (NTRS)

    Edelson, Burton I. (editor); Pelton, Joseph N. (editor); 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.

    1993-01-01

    This is Volume 1 (Analytical Chapters) of the final report of the NASA/NSF Panel Satellite Communications Systems and Technology. The panel surveyed advanced technology being developed for commercial use in the satellite communications field in Europe, Japan, and Russia. All aspects of satellite communications were considered, including fixed, broadcast, mobile, personal communications, navigation, low earth orbit, and small satellites. The focus was on experimental and advanced technology being developed in R&D and demonstration programs rather than on today's production capabilities. Focus was on commercial satellite technology, and does not review defense-related or other confidential satellite communications capabilities. The NASA/NSF panel concluded that the United States has lost its leading position in many critical satellite communications technologies. Although U.S. industry retains a leading position in today's marketplace for satellite communications systems and services, this position is largely founded on technologies and capabilities developed in the 1960's and 1970's. Because the United States is losing ground with respect to a wide range of technologies and systems that will be key to future communications markets, the market share of the U.S. satellite communications industry is at risk.

  19. Satellite communications systems and technology. Volume 1; Analytic Chapters

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

    Volume 1 (Analytical Chapters) of the final report of the NASA/NSF Panel Satellite Communications Systems and Technology is presented. The panel surveyed advanced technology being developed for commercial use in the satellite communications field in Europe, Japan, and Russia. All aspects of satellite communications were considered, including fixed, broadcast, mobile, personal communications, navigation, low earth orbit, and small satellites. The focus of the study was on experimental and advanced technology being developed in R&D and demonstration programs rather than on today's production capabilities. The report focuses on commercial satellite technology, and does not review defense-related or other confidential satellite communications capabilities. The NASA/NSF panel concluded that the United States has lost its leading position in many critical satellite communications technologies. Although U.S. industry retains a leading position in today's marketplace for satellite communications systems and services, this position is largely founded on technologies and capabilities developed in the 1960s and 1970s. Because the United States is losing ground with respect to a wide range of technologies and systems that will be key to future communications markets, the market share of the U.S. satellite communications industry is at risk.

  20. Broadband satellite communication ... -Google Livros Descrio geral

    E-print Network

    Monteiro, Edmundo

    Broadband satellite communication ... - Google Livros Descrição geral > Pré-visualização Críticas satellite communication ... - Google Livros Esta é uma pré-visualização. O total de páginas apresentadasC&printsec=frontcover&hl=pt-PT&source=gbs_v2_summary_r&cad=0 (2 of 28) [12-08-2009 11:21:11] #12;Broadband satellite communication ... - Google

  1. NASA Launches Next-Generation Communications Satellite

    E-print Network

    Christian, Eric

    NASA Launches Next-Generation Communications Satellite Pg 3 Triumph Over Tragedy: Columbia's Last in Florida. "TDRS-K bolsters our network of satellites that provides essential communications to support Goddard View The Weekly ­ 2 NASA Launches Next-Generation Communications Satellite ­ 3 Dinosaur Footprints

  2. The Aerospace Corporation 2009 Communication Satellite Systems

    E-print Network

    Low, Steven H.

    © The Aerospace Corporation 2009 Communication Satellite Systems Trends and Network Aspects Paul://www.aero.org/ Lee Center, Caltech 13 April 2009 #12;22 Communication Satellites · Brief History by Decade · Trends: ­ Communication Satellites, fifth edition, by D. Martin, P. Anderson, L. Bartamian, Aerospace / AIAA Press, 2006

  3. Application of the aeronautical mobile satellite service (AMSS) and the providers of the service

    NASA Astrophysics Data System (ADS)

    Brangier, Francis

    1991-07-01

    The paper describes the different potential users of the AMSS, their requirements, and foreseen applications. The AMSS will be provided by several satellite-communication organizations, including INMARSAT, ARINC, SITA, and various national companies. Consideration is given to air-traffic-control services, aircraft operations communication, administrative communication, passenger communication services, and the problem of compatibility among these components.

  4. Telecom 1: French domestic communications satellite system

    NASA Astrophysics Data System (ADS)

    1981-05-01

    Services supplied by TELECOM 1, the components of the TELECOM 1 system, the industrial organization, and the project schedule are described. The TELECOM 1 system: provides broadband digital links between companies in France and neighboring states; routes telephone communications and television broadcasts between France and its overseas territories; and handles government communications. A ground control and monitoring station operates the TDMA system and supervises ground station performance, synchronizes the bursts from each station, surveys the repeaters and provides the billing. Three satellites, including one spare, developed from OTS, MARECS and ECS designs, are launched by Ariane.

  5. Research Supporting Satellite Communications Technology

    NASA Technical Reports Server (NTRS)

    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. Communications satellite no. 2 (CS-2)

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The purpose of the Japanese CS-2 satellite is to provide national communications and industrial communications, such as special emergency and remote communications, and to contribute to the development of technology pertaining to communications satellites. Description and operating parameters of the following satellite components are presented: structure, communications system, telemetry/command system, electric power system, attitude and antenna control system, secondary propulsion system, apogee motor, framework, and heat control system.

  7. Spacecraft in switch matrix for wide band service applicatons in 30/20 GHz communications satellite systems

    NASA Technical Reports Server (NTRS)

    Cory, B. J.

    1982-01-01

    Bandwidth, switching speed, off-state isolation, and reliability over a ten-year mission were factors in determining the optimum available technology for satellite communications switching in 1982. A proof of concept model for a 20 x 20 coupled crossbar switch matrix designed with FET devices for microwave switching and with high speed CMOS LIS for switch crosspoint addressing was fabricated and tested. Results show the design is feasible for application in a multichannel SS-TDMA communications system. Expandibility can readily be achieved with this design. A conceptual design study for a 100 x 100 switch matrix utilizing a coupled crossbar architecture implemented with a monolithic microwave integrated circuits revealed technology needs for high capacity switch matrices.

  8. Application of the Iridium Satellite System to Aeronautical Communications

    NASA Technical Reports Server (NTRS)

    Kerczewski, Robert J.; Meza, Mike; Gupta, Om

    2008-01-01

    The next generation air transportation system will require greater air-ground communications capacity to accommodate more air traffic with increased safety and efficiency. Communications will remain primarily terrestrially based, but satellite communications will have an increased role. Inmarsat s aeronautical services have been approved and are in use for aeronautical safety communications provided by geostationary satellites. More recently the approval process for the Iridium low earth orbit constellation is nearing completion. The current Iridium system will be able to provide basic air traffic services communications suitable for oceanic, remote and polar regions. The planned second generation of the Iridium system, called Iridium NEXT, will provide enhanced capabilities and enable a greater role in the future of aeronautical communications. This paper will review the potential role of satellite communications in the future of air transportation, the Iridium approval process and relevant system testing, and the potential role of Iridium NEXT.

  9. Trends in NASA communication satellites

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

    Satellite telecommunications can help to satisfy several national needs such as education, health care, cultural opportunities, and data transfer. There are current experiments being conducted with NASA spacecraft ATS 1, 3, and 5 in an attempt to satisfy these national needs. Future experiments are planned for the ATS F/G and CTS spacecrafts. The next generation of communications satellites must provide multiple region coverage, multichannel capability, high quality TV pictures, and must allow low cost ground receivers to be used. The proposed NASA spacecrafts, ATS H/I, will satisfy these requirements. Other countries of the world can benefit from ATS H/I technology.

  10. Satellite communications systems and technology. Executive Summary

    NASA Technical Reports Server (NTRS)

    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; Mahle, Christoph E.

    1993-01-01

    NASA and the National Science Foundation (NSF) commissioned a panel of US 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 travelled to Europe, Japan, and Russia to gather information first-hand. They visited 17 sites in Europe, 20 sites in Japan, and four in Russia. These included major manufacturers, government organizations, service providers, and associated R&D facilities. The panel's report was reviewed by the sites visited, by the panel, and by representatives of US industry. The report details the information collected and compares it to US activities.

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

    NASA Technical Reports Server (NTRS)

    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.

  12. A review of mobile satellite communication systems

    NASA Astrophysics Data System (ADS)

    Kondo, Kimio

    1990-03-01

    This article describes mobile satellite systems in the planning or development stage such as MSAT, AMSC and Geostar and mobile satellite communication experiments such as PRODAT. Studies on the system such as T-SAT are also reviewed. In addition, Japanese ETS-V and ETS-VI are described. The development of mobile-satellite communication systems is promoted along with those of communication and satellite technologies.

  13. Evaluating the Peruvian Rural Communication Services Project.

    ERIC Educational Resources Information Center

    Mayo, John

    1988-01-01

    Reviews the Peruvian Rural Communication Services (PRCS) Project and outlines selected findings. Topics discussed include a brief description of Peru's economic and social conditions; satellite communication systems; audio teleconferencing; telephone service; planning and administration; research design features; data collection; and project…

  14. Large communication-satellite antenna

    Microsoft Academic Search

    J. Schultz

    1977-01-01

    Antennas planned for future space satellites will be too large to be carried aloft in an assembled configuration. They will therefore have to be deployable. A design concept for such antennas, usable at UHF-to-microwave frequencies, is discussed with reference to communications system parameters, and structural analysis. Various possibilities for the electrical configuration of a flat-faced phased-array are presented, including space

  15. Communications and media services

    NASA Technical Reports Server (NTRS)

    Mcculla, James W.; Kukowski, James F.

    1990-01-01

    NASA's internal and external communication methods are reviewed. NASA information services for the media, for the public, and for employees are discussed. Consideration is given to electron information distribution, the NASA TV-audio system, the NASA broadcast news service, astronaut appearances, technology and information exhibits, speaker services, and NASA news reports for internal communications. Also, the NASA worldwide electronic mail network is described and trends for future NASA communications and media services are outlined.

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

    NASA Technical Reports Server (NTRS)

    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.

  17. Power Versus Stabilization for Laser Satellite Communication

    Microsoft Academic Search

    Shlomi Arnon

    1999-01-01

    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

  18. Ground-to-satellite laser communication experiments

    Microsoft Academic Search

    Monio Toyoshima; Yoshihisa Takayama; Takashi Takahashi; Kenji Suzuki; Shinichi Kimura; Kenichi Takizawa; Tosbiaki Kuri; Werner Klaus; Masahiro Toyoda; Hiroo Kunimori; Takashi Jono; Katsuyoshi Arai

    2008-01-01

    Ground-to-satellite laser communication experiments between the optical ground station located in Koganei, central Tokyo, and a low earth orbit (LEO) satellite were jointly performed by the Japan Aerospace Exploration Agency and the National Institute of Information and Communications Technology. In 18 trials during three non-consecutive months, the satellite was acquired and tracked 61 % of the time, when clear or

  19. Optical System in Laser Inter-Satellites Communication

    Microsoft Academic Search

    Zhou Li; Wen Chuanhua; Liu Baoming

    2008-01-01

    We know that Inter-satellites communication is a very important to us. However, real global coverage can only be achieved by satellite systems. Satellites communication is the most important mean of the communication network. The traditional satellites communication and inter-satellites links are built by microwave. Recent years, laser links for inter-satellites communication are becoming more and more important.

  20. Optimal Energy Allocation and Admission Control for Communications Satellites

    E-print Network

    Modiano, Eytan

    1 Optimal Energy Allocation and Admission Control for Communications Satellites Alvin Fu, Eytan control for communications satellites in earth orbit. These satellites receive requests for transmis- sion allocation problems in wireless commu- nications. Keywords-- Satellite, Communication, Resource Alloca- tion

  1. Information Delivery Through Broadcasting in Satellite Communication Networks

    E-print Network

    Tassiulas, Leandros

    Information Delivery Through Broadcasting in Satellite Communication Networks Leandros Tassiulas­range multicasting capability of satellites and the asymmetry of satellite communications (high bandwidth downlink. We consider a data broadcasting model that is encountered in most asymmetric satellite communication

  2. Teleradiology and telemedicine using the advanced communications technology satellite and international maritime satellite at varying bandwidths

    Microsoft Academic Search

    Robert E. de Treville; Stephen D. Scotti; Morgan P. Williamson; Eric J. Olson; Linda H. Brink; Ken Isle; Peter Kafaro

    1995-01-01

    The United States military gained experience with a deployed telemedicine team and unit during the deployment of United States military troops to Haiti as part of `Operation Uphold Democracy.' Consults were conducted primarily between the 28th combat support hospital in Haiti and Walter Reed Army Medical Center in Washington, D.C. The Advanced Communications Technology Satellite and International Maritime Satellite services

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

    NASA Technical Reports Server (NTRS)

    Pepin, Gerard R.

    1992-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Pepin, Gerard R.

    1992-01-01

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

  5. Satellite communications systems and technology. Volume 2: Site reports

    NASA Technical Reports Server (NTRS)

    Edelson, Burton I. (editor); Pelton, Joseph N. (editor); 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.

    1993-01-01

    This is volume 2 of the final report of the NASA/NSF Panel on Satellite Communications Systems and Technology. It consists of the site reports from the panel's visits to satellite communications facilities and laboratories in Europe, Japan, and Russia. The Executive Summary of the panel's final report is published separately. Volume 1, also published separately, consists of the panel's analytical chapters. Information on ordering the Executive Summary and Volume 1 from the National Technical Information Service is included.

  6. Experiments on aeronautical satellite communications using ETS-V satellite

    Microsoft Academic Search

    S. Ohmori; Y. Hase; H. Wakana; S. Taira

    1992-01-01

    The world's first aeronautical satellite communication experiments, conducted at L-band frequencies using a commercial aircraft, are described. An airborne antenna with electronically steerable beam and communication equipment was installed in a B-747F freighter flying over transoceanic flight routes. The satellite used in these experiments is the Engineering Test Satellite-Five (ETS-V). During the test period, various experiments, such as antenna pattern

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

    Microsoft Academic Search

    Shingo Ohmori; Shunkichi Isobe; Makoto Takeuchi; Hideyuki Naito

    1993-01-01

    Early in the 21st century, the demand for personal communications using mobile, hand-held, and VSAT terminals will rapidly increase. In a future system, many different types of services should be provided with one-hop connection. The Communications Research Laboratory (CRL) has studied a future advanced mobile satellite communications system using millimeter wave and Ka band. In 1990, CRL started the Communications

  8. A new antenna concept for satellite communications

    NASA Technical Reports Server (NTRS)

    Skahill, G.; Ciccolella, D.

    1982-01-01

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

  9. Achieving QoS for TCP traffic in Satellite Networks with Differentiated Services Arjan Durresi1

    E-print Network

    Durresi, Arjan

    intersatellite links, advanced link access methods and multicast technologies. Many new satellite communication. However, satellite systems have several inherent constraints. The resources of the satellite communication1 Achieving QoS for TCP traffic in Satellite Networks with Differentiated Services Arjan Durresi1

  10. Satellite services handbook. Interface guidelines

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Satellite interfaces for on orbit servicing, both manned and unmanned are identified, and is intended to be used by designers of space vehicles, both foreign and domestic. A primary concern is for design of interfaces with the astronaut in the loop, especially extravehicular activity, but also intravehicular activity and operations that are remote but have man-in-the-loop. The main emphasis is on servicing in low earth orbits from the Space Shuttle and also from the Space Station or other platforms.

  11. Satellite Antenna Pointing Procedure Driven by the Ground Service Quality

    Microsoft Academic Search

    Yoshitsugu Yasui

    2008-01-01

    A satellite antenna alignment technique is proposed to ensure terrestrial service quality for users. The antenna bore sight orientation is calculated directly from measured data acquired from general ground receivers, which intercept the communication radio waves from any position on the earth's surface. The method coordinates the satellite pointing parameters with signal strength at the receivers while considering location-specific geographical

  12. Resource allocation and scheduling for communication satellites with advanced transmission antennas

    E-print Network

    Choi, Jihwan Patrick, 1975-

    2006-01-01

    For multimedia and other data services over satellite networks, the efficient management of scarce satellite communication resources is critical for the economic competitiveness of the medium. To support a broad spectrum ...

  13. Prediction of fading phenomena in land-satellite communication links

    Microsoft Academic Search

    N. Blaunstein; Y. Cohen; M. Hayakawa

    2010-01-01

    This paper addresses the problem of prediction of probability of successful radio communication of any mobile or stationary subscriber located in areas of service such as complex urban environments characterized by nonline-of-sight propagation conditions, which limit GPS, Low Earth Orbit, and Medium Earth Orbit services in land-satellite communications. It presents a self-consistent physical-statistical approach for predicting fading phenomena usually occurring

  14. Photovoltaic solar arrays for communication satellites

    Microsoft Academic Search

    W. I. Berks; W. Luft

    1971-01-01

    Photovoltaic solar arrays are the principal means of converting solar energy to electrical energy for satellites. Array configurations depend on the spacecraft stabilization concept, orbit, and power requirements. The current generation of communication satellites are spin-stabilized in synchronous equatorial orbits; their arrays are spinning cylinders. As satellite power requirements increase, it is expected that the trend will be toward extendible

  15. ARCHITECTING A COMMUNICATION SATELLITE PRODUCT LINE

    Microsoft Academic Search

    Rania Hassan; Olivier de Weck; Philip Springmann

    Current unfavorable market conditions have shifted the preference of commercial communication satellite operators from large spacecraft systems with high bandwidth capacities, to small and medium size spacecraft. However, most satellite manufacturers have not caught up yet with this trend and are still positioned as providers of large capacity satellite systems. This paper investigates the application of product family concepts to

  16. Satellite communications in Europe - The earth-segment market

    NASA Astrophysics Data System (ADS)

    Bartholome, P.; Hughes, C. D.

    1985-11-01

    The earth segment market of the new European satellite telecommunications field is projected for the next decade, and suggestions are made for its improvement. The home market for large Eutelsat stations (comprising the international telephone and television exchanges) is being dominated by the Japanese industry. Small station fixed satellite services (including business multiservices, distribution of CATV and SMATV, and the distribution of information to closed user groups) could create a substantial market for European industry with the relaxation of regulatory restraints. Four high-power satellites currently under development will open a market in direct broadcasting (DBS). Although the potential for mobile-satellite services (land mobile and maritime communications) is great, the European industry possesses only 15 percent of the present Inmarsat ship-terminal market. It is concluded that European industrial competitiveness could be increased by a general telecommunications policy for regulation, standardization, and research. Tables summarizing the telecommunications service potential and the satellite transponders available for TV distribution, are included.

  17. Applications of MEMS in communication satellites

    Microsoft Academic Search

    S. J. Fiedziuszko

    2000-01-01

    Micro-electro-mechanical-systems (MEMS) are finding more and more applications in microwave systems. Communications satellites, which typically have a large microwave hardware content, will be discussed as an example of these potential applications. In the first part, general MEMS technology and early examples will be described. Next, space applications of MEMS (sensors, actuators, propulsion etc.) in a communications satellite vehicle (bus) will

  18. Digital communications: Satellite\\/earth station engineering

    Microsoft Academic Search

    K. Feher

    1983-01-01

    The analysis and design of the elements of modern satellite communications systems are considered. Illustrative earth station and satellite communications subsystems are first introduced, and link budget calculations are discussed. Signal processing and multiplexing techniques used in terrestrial interface subsystems are described, as are baseband transmission systems principles and design techniques. The principles, performance analysis, and design tools of power-efficient

  19. EHF satellite communication systems for mobile users

    Microsoft Academic Search

    R. E. Eaves

    1979-01-01

    The large amounts of spectrum available in the EHF and upper SHF region offer the potential to provide secure satellite communications to large numbers of users. However, the cost-effective realization of this potential requires the development of satellite communication system architectures which will serve small and relatively inexpensive terminals. Conventional transponder systems are inadequate both in the security they provide

  20. Architectural trends in military satellite communications systems

    Microsoft Academic Search

    P. C. Jain

    1990-01-01

    A historical overview of military communications by satellites and a detailed description of current systems are provided. The capabilities of present systems are reviewed in relation to user requirements and threats. It is concluded that use of satellite communications by a large number of small-terminal users (aircraft, ships, submarines, and land mobiles) still requires major technological innovations to meet needs

  1. A Dynamic Routing Concept for ATM-Based Satellite Personal Communication Networks

    Microsoft Academic Search

    Markus Werner

    1997-01-01

    Satellite systems are going to build a part of the future personal communications infrastructure. The first-generation candidates for satellite personal communication networks (S-PCN) will rely on low Earth orbit (LEO) and medium Earth orbit (MEO) constellations. A noticeable trend in this field is toward broadband services and the use of ATM. For LEO satellite systems employing intersatellite links (ISLs), this

  2. Turbo-Coded APSK Modulations Design for Satellite Broadband Communications

    E-print Network

    Guillén i Fàbregas, Albert

    Turbo-Coded APSK Modulations Design for Satellite Broadband Communications Riccardo De Gaudenzi with application to satellite broad- band communications. APSK represents an attractive modulation format systems. 1 Introduction Satellite communication systems strength lies in their ability to efficiently

  3. 22nd AIAA International Communications Satellite Systems Conference & Exhibit 2004 9.12 May 2004, Monterey, California

    E-print Network

    Baras, John S.

    22nd AIAA International Communications Satellite Systems Conference & Exhibit 2004 9.12 May 2004. Barast Departmentof Electrical and Computer Engineering and Centerfor Satellite and Hybrid Communication communication has placed focus on communication satellites as an efficient way to extend the multicast services

  4. Inmarsat and personal mobile satellite services

    NASA Astrophysics Data System (ADS)

    McDougal, Patrick; Barendse, Victor

    Personal communications - mobile satellite services (PC-MSS) hold much promise as a profitable business opportunity for a number of interested operators and manufacturers. What will be their impact on the overall mobile communications landscape, and what role will they play in the drive towards the universal personal communicator? It is the thesis of this paper that PC-MSS can provide one of the critical enabling technologies to allow a more rapid, global assimilation of personal mobile communications. Terrestrial mobile communications are local by definition, both in terms of service reach and regulatory oversight. It is estimated that cellular, and other forms of terrestrial mobile communications, will cover over 50% of the world's population, but only 15% of the land mass area by the year 2000. PC-MSS will allow 'cellular extension' to interested users in the uncovered parts of the world. The market opportunity is established and technical solutions are available. However 'user cooperation' will be required and cross mapping of market needs to the technology solutions is the key to financially viable solutions. The potential political and regulatory hurdles are daunting. Inmarsat, as the existing global MSS partnership, is already introducing PC-MSS products and services in the 1990s. The widespread use of briefcase satphones (Inm-M), laptop-sized data terminals (Inm-C), and pocket satpagers (Inm-paging) will break new ground in reshaping the international regulatory context of mobile communications, and in initiating the optimal public switched network integration necessary for global interconnect. It is suggested that this evolutionary approach, by means of international consensus-building within a global partnership of operators, is an effective and proven method to ensure both a sufficient financial return for investors, and fair and equitable access of these services for all countries and users.

  5. Perspectives on European satellite communications

    NASA Astrophysics Data System (ADS)

    Weber, H.

    1984-09-01

    The Intelsat System is the classic intercontinental transmission system for television signals and large FDM beams is outlined. An important medium for the transmission of small beams and of individual telephone communication traffic. With its satellites of continuously increasing size and complexity the fifth generation is now in operation, the sixth in development it provides the following capacities in several areas of its radiation: the 6/4-GHz range (C band) and the 14/11-GHz range (Ku band). The prevailing transmission technology in the Intelsat System was analog, however changeover to digital transmission technology with pulse code modulation (PCM) as source coding and using time division multiple access (TDMA), has commenced with the construction of the ground stations.

  6. Communications Satellite System by Using Moon Orbit Satellite Constellation

    Microsoft Academic Search

    Sang-Uk Lee; Jae-Hoon Kim; Seong-Pal Lee

    2003-01-01

    A communications satellite system placed in three-Lagrange points, L3, L4, and L5, of the restricted three-body problem in Earth-Moon system is proposed in this paper. LEO satellite constellation has been another choice of communications system. The proposed system which is alternatives of limited geostationary orbit resources, has some weak points such as long distance from the Earth, relatively expensive launch

  7. Issues in satellite personal communication systems

    Microsoft Academic Search

    Erich Lutz

    1998-01-01

    In the paper various issues in personal satellite communications are addressed. Basic geostationary and non?geostationary\\u000a satellite constellations are considered. The narrowband and wideband characterization of the mobile satellite channel and\\u000a related system implications are discussed. Satellite diversity is presented as a measure to overcome signal shadowing. The\\u000a capacity of TDMA and CDMA multiple access is estimated, taking into account co?channel

  8. Space industrialization - Education. [via communication satellites

    NASA Technical Reports Server (NTRS)

    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.

  9. Variable data rate modem for low Earth orbiting satellite (LEOS) communication

    Microsoft Academic Search

    C. H. Lee

    1995-01-01

    There is wide interest in providing mobile satellite services (MSS) via low Earth orbiting satellite (LEOS) instead of by the traditional geosynchronous satellites (GEOS). This development conforms with the trends in personal communication services (PCS) where low cost, low power and high volume users are the goals. The distinct features of LEOS are characterized by its low altitude (4000 km

  10. On-line bandwidth control for quality of service mapping over satellite independent service access points

    Microsoft Academic Search

    Mario Marchese; Maurizio Mongelli

    2006-01-01

    The Quality of Service (QoS) provision requires the cooperation of all network layers from bottom to top. More spe- cifically, for Broadband Satellite Multimedia (BSM) communications, the physical layers (strictly satellite dependent) are isolated from the rest by a Satellite Independent Service Access Point (SI-SAP), which should offer specific QoS to IP and the upper layers. The structure of SI-SAP

  11. Development of maritime satellite communication aids in the USSR

    NASA Astrophysics Data System (ADS)

    Cherniaev, R.; Volodin, V.; Atserov, Iu.; Pcheliakov, L.; D'Iakov, V.

    1987-10-01

    Maritime satellite communications facilities developed in the USSR to meet Inmarsat technical requirements are described. The availability of coast earth station special-purpose software supports such services as teletex reception/transmission, facsimile transmit/receive, store and forward, and relaying of multiple-address messages. The USSR has proposed its Proton rocket as a launch vehicle for a new series of Inmarsat satellites.

  12. Keep in Touch: Communications and Satellites

    NSDL National Science Digital Library

    Integrated Teaching and Learning Program,

    How do we communicate with each other? How do we communicate with people who are close by? How do we communicate with people who are far away? In this lesson, students will explore the role of communications and how satellites help people communicate with others far away and in remote areas with nothing around (i.e., no obvious telecommunications equipment). Students will learn about how engineers design satellites to benefit life on Earth. This lesson also introduces the theme of the rockets curricular unit.

  13. Recent Korean R&D in Satellite Communications

    NASA Astrophysics Data System (ADS)

    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 a collaborative R&D with Korea for mutual benefit of the future.

  14. Vibration noise control in laser satellite communication

    Microsoft Academic Search

    Avigdor Saksonov; Shlomi Arnon; Norman S. Kopeika

    2001-01-01

    Laser satellite communication has become especially attractive in recent years. Because the laser beam width is narrow than in the RF or microwave range, the transmitted optical power may be significantly reduced. This leads to development of miniature communication systems with extremely low power consumption. On the other hand, the laser communication channel is very sensitive to vibrations of the

  15. A figure of merit for competing communications satellite designs

    NASA Technical Reports Server (NTRS)

    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.

  16. Satellite services system analysis study. Volume 3: Service equipment requirements

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Service equipment mission requirements are discussed. On-orbit operations, satellite classes, and reference missions are included. Service equipment usage and requirements are considered. Equipment identification methodology is discussed. Service equipment usage is analyzed, including initial launch, revisit, Earth return, and orbital storage. A summary of service requirements and equipment is presented, including service equipment status, even interaction, satellite features, and observations.

  17. Spacecraft design project: High latitude communications satellite

    NASA Technical Reports Server (NTRS)

    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.

  18. Communication Capacity Optimization for Broadband Satellite Communication Systems

    NASA Astrophysics Data System (ADS)

    Nakasuga, Yoshinori; Mitsugi, Jin; Ueba, Masazumi; Mizuno, Hideki

    2002-01-01

    ground-based access systems, such as FTTH, ADSL and even terrestrial cellular systems, are only available within limited geographical areas, broadband satellite communication systems that can cover unlimited service area have attracted wide interest. However, the success of broadband satellite communication depends heavily on the cost of user terminals and satellite circuits. and frequency bandwidth, which involves design parameters. For such parameters, we must consider modulation, coding, the number of radiating beams and the number of areas in which frequency bandwidth can be reused. These parameters should be chosen such that maximum communication capacity can be provided with minimum system resources under a designated rain attenuation and interference environment. The difficulty in optimization stems from the number of design parameters and the interactions between them. The optimization also has to be done in a manner such that the service provider can determine the relation between the service cost and the service grade. The service grade can be expressed in terms of the available user information rate, return link as well as forward link, and the number of available communication channels, while the system cost can be expressed in terms of required satellite power and the bandwidth. power and bandwidth parameters. In the method, the number of spot beams, the number of repeated bandwidth areas and the type of modulation are separately determined for the return and forward link. From the selected design parameters, the relationship between bandwidth capacity and power capacity is derived assuming they are linear. The power and bandwidth required for the return and forward link are then integrated by applying a linear programming method. The constraints in linear programming are power and bandwidth. To denote the system resource management proficiency, we introduce an index called power-utilization efficiency, which is a ratio of the maximum capacity to the required power. systems that have 15 or 35 spot beams. Since circuit quality degradation in Ku band systems due to the propagation environments is less than that in Ka band systems, the power-utilization efficiency of the Ku band is 1.25 times more that of the Ka band. On the other hand, the total capacity of the Ka band is 3.5 times that of the Ku band since the allocated bandwidth in the Ku band is narrower than that of the Ka band. Bandwidth reuse is an effective way to increase total available bandwidth. For the same service area and the same number of reused bandwidths, increasing the number of spot beams can reduce the interference between different areas assigned the same frequency, since the distance between those areas widens. This enables total capacity and power-utilization efficiency for a 35-spot-beam system to be more than 2.2 and 2.75 times greater, respectively, than for a 15-spot-beam system. limited transmission power of the user terminal. Therefore, the return link transponder requires a higher transmission power level to compensate for this limitation. On the other hand, a high-quality downlink is also required for the forward link because of the small size of the user terminal antenna. However, the quality of the forward link can be maintained since it is possible to increase uplink quality by improving hub-station performance. This makes it possible to suppress the increase in the transmission power of the forward link transponder in comparison with that of the return link transponder. As an example, we compared two cases, in one of which the capacity ratio (forward link capacity divided by the return link capacity) was 2.0 and in the other of which it was 10.0. We found that the amount of capacity and power utilization efficiency were, respectively, 33% and 50% greater for the latter case than for the former case. applications.

  19. Satellite fixed communications service: A forecast of potential domestic demand through the year 2000. Volume 3: Appendices

    NASA Astrophysics Data System (ADS)

    Kratochvil, D.; Bowyer, J.; Bhushan, C.; Steinnagel, K.; Kaushal, D.; Al-Kinani, G.

    1983-09-01

    Voice applications, data applications, video applications, impacted baseline forecasts, market distribution model, net long haul forecasts, trunking earth station definition and costs, trunking space segment cost, trunking entrance/exit links, trunking network costs and crossover distances with terrestrial tariffs, net addressable forecasts, capacity requirements, improving spectrum utilization, satellite system market development, and the 30/20 net accessible market are considered.

  20. Microwave intersatellite links for communications satellites

    NASA Technical Reports Server (NTRS)

    Welti, G. R.

    1982-01-01

    Applications and interface requirements for intersatellite links (ISLs) between commercial communications satellites are reviewed, ranging from ISLs between widely separated satellites to ISLs between clustered satellites. On-board processing architectures for ISLs employing a variety of modulation schemes are described. These schemes include FM remodulation and QPSK regeneration in combination with switching and buffering. The various architectures are compared in terms of complexity, required performance, antenna size, mass, and power.

  1. Narrow-Band Applications of Communications Satellites.

    ERIC Educational Resources Information Center

    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…

  2. Advances in multibeam communications satellite antennas

    Microsoft Academic Search

    A. I. Zaghloul; Y. Hwang; R. M. Sorbello; F. T. Assal

    1990-01-01

    The evolution of satellite antennas over the past quarter of a century is presented. Five major areas of advances in communications satellite antenna technology are reviewed: single offset reflectors with feed arrays, shaped reflector systems, active phased arrays, phased-array-fed dual reflector systems, and lightweight feed elements. Examples are given of existing systems and of the ongoing development of new technologies

  3. Satellite Communication and Development: A Reassessment.

    ERIC Educational Resources Information Center

    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 application of…

  4. Large communications platforms versus smaller satellites

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Communications systems using large platforms are compared with systems using conventional satellites. Systems models were generated and compared for U.S. domestic application and for 1 INTELSAT's international and domestic transponder lease application. Technology advances were assumed the platforms and the evolution of conventional satellites.

  5. The role of rain in satellite communications

    Microsoft Academic Search

    D. C. Hogg; Ta-Shing Chu

    1975-01-01

    The most fundamental obstacle encountered in design of satellite communication systems at frequencies above 10 GHz is attenuation by rain. The microwave power radiated toward an earth station, being limited by factors such as available primary power and size of antenna on the satellite, is insufficient, with present technology, to overcome the large attenuation produced by intense rain cells on

  6. Strategic satellite communications come of age

    Microsoft Academic Search

    J. H. Gruetzmacher

    1979-01-01

    The Afsatcom (Air Force Satellite Communications) system is described, discussing the smooth transition from Afsatcom I, with initial operational capability attained in Spring of 1979, to SSS (Strategic Satellite System) or Afsatcom II in the late 1980's. The Afsatcom system is designed to direct the Single Integrated Operations Plan (SIOP) forces, composed of U.S. Air Force bombers, ICBMs, ALCMs, and

  7. Handbook on satellite communications and broadcasting

    Microsoft Academic Search

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

    1983-01-01

    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

  8. Future Trends in Military Communication Satellite Repeaters

    Microsoft Academic Search

    D. P. Sullivan

    1970-01-01

    The future development trends in military communication satellite repeaters will be dictated by greater spacecraft capability in terms of payload size, weight, power, and complexity, and attempts to better satisfy the satellite user's needs and desires. This paper presents the basic repeater configurations that have been employed and those that can be expected in the future, along with the user

  9. The Arctic Regional Communications Small SATellite (ARCSAT)

    NASA Technical Reports Server (NTRS)

    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.

  10. Communication satellites: Guidelines for a strategic plan

    NASA Technical Reports Server (NTRS)

    1987-01-01

    To maintain and augment the leadership that the United States has enjoyed and to ensure that the nation is investing sufficiently and wisely to this purpose, a strategic plan for satellite communications research and development was prepared by NASA. Guidelines and recommendations for a NASA plan to support this objective and for the conduct of communication satellite research and development program over the next 25 years were generated. The guidelines are briefly summarized.

  11. Modelling of handover of multimedia traffic in mobile satellite communication

    Microsoft Academic Search

    A. Sali; N. K. Noordin; B. M. Ali; R. K. Z. Sahbudin; A. Anthony; Ng Chee Kyun

    2002-01-01

    This paper presents the handover management in mobile satellite communications with multimedia traffic. Multimedia traffic is becoming the next hop in mobile satellite communication, due to its demand. The coverage of the satellite network knows no boundary and with the concept of the broadband satellite network, communication for multimedia and high-data rate multimedia communications can be provided. The handover initiation

  12. Explanatory information for news conference on satellite communications

    NASA Technical Reports Server (NTRS)

    1983-01-01

    The CS-2 communications satellite which has features such as frequencies of the 30/20GHz band, demand assign time division multiple access, improved ship-to-satellite communications methods, and multibeam satellite communications methods. Research is continuing towards the production of larger, more economical communication systems via satellite which have greater efficiency and capacity.

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

    NASA Technical Reports Server (NTRS)

    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.

  14. The Globalstar mobile satellite system for worldwide personal communications

    NASA Astrophysics Data System (ADS)

    Wiedeman, Robert A.; Viterbi, Andrew J.

    Loral Aerospace Corporation along with Qualcomm Inc. have developed a satellite system which offers global mobile voice and data services to and from handheld and mobile user terminals with omni-directional antennas. By combining the use of low-earth orbit (LEO) satellites with existing terrestrial communications systems and innovative, highly efficient spread spectrum techniques, the Globalstar system provides users with low-cost, reliable communications throughout the world. The Globalstar space segment consists of a constellation of 48 LEO satellites in circular orbits with 750 NM (1389 km) altitude. Each satellite communicates with the mobile users via the satellite-user links and with gateway stations. The gateway stations handle the interface between the Globalstar network and the OSTN/PLMN systems. Globalstar transceivers are similar to currently proposed digital cellular telephones in size and have a serial number that will allow the end user to make and receive calls from or to that device anywhere in the world. The Globalstar system is designed to operate as a complement to existing local, long-distance, public, private and specialized telecommunications networks. Service is primarily designed to serve the rural and thin route communications needs of consumers, government users, and private networks.

  15. The future for domestic communications satellites - Lease or buy

    NASA Astrophysics Data System (ADS)

    Rooney, K. J.

    1982-04-01

    The demand for leased satellite communications services is growing at such a rate that a dedicated leasing satellite system is envisioned to deal with the demand. The most economical solution would be three similarly designed 24-channel capacity satellites with on-orbit antenna beam reconfiguration offering regional C-band coverage and situated over America, Africa, and Asia. Spatial frequency reuse is not considered necessary until at least the next generation. A two-meter antenna projecting a three dB beamwidth nearly three degrees in diameter at 4 GHz can achieve global coverage with only 19 adjacent beams at the aforementioned locations. Circular polarization will be continued in leasing. It is proposed to operate dual orthogonal polarization frequency reuse for uplink and downlink to increase the available capacity. The communications repeater is discussed in detail together with a glossary of terms and an economic analysis of the competition from dedicated domestic satellites.

  16. High-speed satellite mobile communications: technologies and challenges

    Microsoft Academic Search

    MOHAMED IBNKAHLA; QUAZI MEHBUBAR RAHMAN; AHMED IYANDA SULYMAN; HISHAM ABDULHUSSEIN AL-ASADY; Jun Yuan; AHMED SAFWAT

    2004-01-01

    Central features of future 4G mobile communication systems are high-speed data transmission (up to 1 Gb\\/s) and interactive multimedia services. For effective delivery of these services, the network must satisfy some stringent QoS metrics, defined typically in terms of maximum delay and\\/or minimum throughput. Mobile satellite systems will be fully integrated with the terrestrial cellular systems to provide ubiquitous global

  17. Use of low orbital satellite communications systems for humanitarian programs

    NASA Technical Reports Server (NTRS)

    Vlasov, Vladimir N.; Gorkovoy, Vladimir

    1991-01-01

    Communication and information exchange play a decisive role in progress and social development. However, in many parts of the world the communication infrastructure is inadequate and the capacity for on-line exchange of information may not exist. This is true of underdeveloped countries, remote and relatively inaccessible regions, sites of natural disasters, and of all cases where the resources needed to create complex communication systems are limited. The creation of an inexpensive space communications system to service such areas is therefore a high priority task. In addition to a relatively low-cost space segment, an inexpensive space communications systems requires a large number of ground terminals, which must be relatively inexpensive, energy efficient (using power generated by storage batteries, or solar arrays, etc.), small in size, and must not require highly expert maintenance. The ground terminals must be portable, and readily deployable. Communications satellites in geostationary orbit at altitudes of about 36,000 km are very expensive and require complex and expensive ground stations and launch vehicles. Given current technology, it is categorically impossible to develop inexpensive satellite systems with portable ground terminals using such satellites. To solve the problem of developing an inexpensive satellite communications system that can operate with relatively small ground stations, including portable terminals, we propose to use a system with satellites in low Earth orbit, at an altitude of 900-1500 km. Because low orbital satellites are much closer to the Earth than geostationary ones and require vastly less energy expenditure by the satellite and ground terminals for transmission of messages, a system using them is relatively inexpensive. Such a system could use portable ground terminals no more complex than ordinary mobile police radios.

  18. Soviet satellite communications science and technology

    SciTech Connect

    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.

  19. Satellite broadcasting - Capabilities for public service

    NASA Technical Reports Server (NTRS)

    Marsten, R. B.

    1975-01-01

    Satellite broadcast services to support health-care and educational transmissions must work with small, low-cost terminals in allocated radio-frequency bands. The ATS-6 spacecraft has successfully demonstrated such capability in the bands of non-technical users. It supports interactive television broadcasting to simple, low-cost terminals in a nationwide series of experiments in the delivery of health-care and educational services. ATS-6 achieves this capability with a very large antenna and moderate transmitter power. The coverage limitations inherent in this approach will be overcome by the joint U.S.-Canadian Communications Technology Satellite to be launched in December 1975. The CTS will demonstrate broadcast capability with new, high-power technology in a newly-allocated radio-frequency band. This will make it possible to use smaller antennas, greatly enlarging the area coverage available to the many nontechnical experimenters using CTS for their own needs. A practical application of these technologies is now in development for operational broadcasting services in Japan.

  20. Satellite multiple access systems for mobile communication

    NASA Technical Reports Server (NTRS)

    Lewis, J. L.

    1979-01-01

    This paper considers multiple access techniques for a mobile radio system which incorporates a geosynchronous orbiting satellite repeater through which mobile terminals communicate. The communication capacities of FDMA, TDMA and CDMA systems are examined for a 4 MHz bandwidth system to serve up to 10,000 users. An FDMA system with multibeam coverage is analyzed in detail. The system includes an order-wire network for demand-access control and reassignment of satellite channels. Satellite and terminal configurations are developed to a block diagram level and system costs and implementation requirements are discussed.

  1. The Advanced Communication Technology Satellite and ISDN

    NASA Technical Reports Server (NTRS)

    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.

  2. Positioning determination and communications using two geostationary satellites

    NASA Astrophysics Data System (ADS)

    Morikawa, Eihisa; Miura, Ryu; Kimura, Kazuhiro; Kawase, Seiichiro; Ohmori, Shingo; Matsumoto, Yasushi; Wakao, Masayoshi

    1992-07-01

    A hybrid satellite communication system has been developed which can provide both communications and positioning services in one system using two geostationary satellites. The experimental system consists of the ETS-V (150 deg E) and INMARSAT (180 deg E), a base earth station (Kashima Space Research Center, Japan), and mobile earth stations. The frequencies between the satellites and mobile stations are 1.6/1.5 GHz. The distinctive feature of this system is that position determination of the mobile earth stations and communication, such as voice and data transmission, can be carried out over the same channel at the same time. Another feature is that the frequency bandwidth of the system is very narrow compared to those of GPS and GEOSTAR. The two types of terminals developed for the experiments with this hybrid system use the single channel per carrier method and the spread spectrum method. An outline of the experimental system is presented, and the estimated positioning accuracy is described.

  3. Communication satellite and related advanced technologies in Japan

    NASA Astrophysics Data System (ADS)

    Takahara, Kiyoshi

    Satellite communications research in Japan is examined, focusing on the development of a high power communications satellite called the Super Bird. The Super Bird uplink frequencies are 14.0-14.4 GHz in the Ku band and 27.5 and 29.25 GHz in the Ka band with downlink frequencies of 12.35-12.75 GHz and 17.7-19.45 GHz for the Ku and Ka bands, respectively. The Ku band has 19 operating channels, while the Ka band has 10. The antenna coverage for both bands includes all of Japan. The service planning, configuration, and fundamental features of the Super Bird are described. Also, the possible development of a multibeam satellite communication system is considered.

  4. Study of spread spectrum multiple access systems for satellite communications with overlay on current services: Executive summary

    NASA Technical Reports Server (NTRS)

    Ha, Tri T.; Pratt, Timothy

    1987-01-01

    Two different methods of generating spread spectrum signals for an overlay service are discussed, and the data rate and efficiency which can be achieved while maintaining low interference with existing traffic are examined.

  5. The history and future of commercial satellite communications

    NASA Astrophysics Data System (ADS)

    Pritchard, W. L.

    1984-05-01

    The development and operations of commercial satellite communications are described. The development of passive satellites and early active satellites is reviewed, a list of operational and planned communications satellite systems is presented, and active satellites are discussed, including global fixed civil telecommunications satellites, regional systems, domestic fixed satellite systems, global mobile systems, domestic mobile and broadcast systems, and experimental satellites. Comparisons with other transmission techniques are made, the use of earth stations is briefly examined, and industrial growth and future trends are considered.

  6. Vibration suppression techniques for optical inter-satellite communications

    Microsoft Academic Search

    Tong Luo; Yu Hu

    2002-01-01

    Optical inter-satellite communications is a promising method in space-based communications. In order to communicate between satellites, the laser beam of the communication partner must be acquired, pointed and tracked. The optical communication transceiver is impacted by the host platform vibration and space environment as payload of the satellite. This paper summarily explains the design requirements of acquisition, pointing and tracking

  7. Repeated Transmissions In Mobile/Satellite Communications

    NASA Technical Reports Server (NTRS)

    Yan, Tsun-Yee; Clare, Loren P.

    1988-01-01

    Repetition increases throughput and decreases delay. Paper discusses theoretical performance of communication system for land-mobile stations with satellite relay using ALOHA random-access protocol modified for repeated transimssions. Methods and conclusions contribute to general understanding of packet communications in fading channels.

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

    ERIC Educational Resources Information Center

    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…

  9. Traveling wave tubes for communication satellites

    Microsoft Academic Search

    ROBERT STRAUSS; JORK BRETTING; ROBERT METIVIER

    1977-01-01

    Traveling wave tubes (TWT's) have contributed markedly to the development of communications satellites. As the prime-power consuming and transmitting device, the major transponder gain element, and the largest contributor to transmission nonlinearities, the TWT has been the focal point for continuous but carefully measured evolutionary improvements. Efficiency improvements continue to be made without compromising desired communications characteristics or tube lifetimes.

  10. Cultural Effects and Uses of Communication Satellites.

    ERIC Educational Resources Information Center

    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…

  11. Satellite Communications in the 1980's.

    ERIC Educational Resources Information Center

    Usunier, Pierre

    Space communications have developed tremendously since 1963 when the National Aeronautics and Space Administration (NASA) launched the synchronous communication satellite, Syncom II, into geostationary orbit. The capacity of that spacecraft was one two-circuit voice channel. Intelsat V, launched in 1980, has a capacity of 12,000 circuits plus two…

  12. The Politics and Technology of Satellite Communications.

    ERIC Educational Resources Information Center

    Galloway, Jonathan F.

    The study discussed in this book approaches the task of understanding the interrelated effects of innovations on society by concentrating on one technological innovation--satellite communications--as it relates to three basic processes: the relation of innovations in communications technology to innovations in policy and the policy-making process,…

  13. Silicon-Germanium Fast Packet Switch Developed for Communications Satellites

    NASA Technical Reports Server (NTRS)

    Quintana, Jorge A.

    1999-01-01

    Emerging multimedia applications and future satellite systems will require high-speed switching networks to accommodate high data-rate traffic among thousands of potential users. This will require advanced switching devices to enable communication between satellites. The NASA Lewis Research Center has been working closely with industry to develop a state-of-the-art fast packet switch (FPS) to fulfill this requirement. Recently, the Satellite Industry Task Force identified the need for high-capacity onboard processing switching components as one of the "grand challenges" for the satellite industry in the 21st century. In response to this challenge, future generations of onboard processing satellites will require low power and low mass components to enable transmission of services in the 100 gigabit (1011 bits) per second (Gbps) range.

  14. High-Latitude Communications Satellite (HILACS)

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The Naval Postgraduate School in the AE 4871 Advanced Spacecraft Design course designed a communications satellite (HILACS) that will provide a continuous UHF communications link between stations located north of the region covered by geosynchronous communications satellites. The communications payload will operate only for that portion of the orbit necessary to provide specific coverage. The satellite orbit is elliptic with perigee at 1204 km in the Southern Hemisphere and an apogee at 14,930 km with 63.4 degrees inclination. Analysis and design of each of the subsystems was done to the extent possible within the constraints of an eleven week quarter and the design and analysis tools available. Work was completed in orbital analysis, the reaction control system, attitude control subsystem, electric power subsystem, telemetry, tracking, and control, thermal control subsystem, and the structures subsystem. The design team consisted of 12 students. Additional support was provided by the Jet Propulsion Laboratory and the Naval Research Laboratory.

  15. Satellite Antenna Pointing Procedure Driven by the Ground Service Quality

    NASA Astrophysics Data System (ADS)

    Yasui, Yoshitsugu

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

  16. Performance of Duplex Communication between a Leo Satellite and Terrestrial Location Using a Geo Constellation

    NASA Technical Reports Server (NTRS)

    Robinson, Daryl C.; Konangi, Vijay K.; Wallett, Thomas M.

    1998-01-01

    A network comprised of a terrestrial site, a constellation of three GEO satellites and a LEO satellite is modeled and simulated. Continuous communication between the terrestrial site and the LEO satellite is facilitated by the GEO satellites. The LEO satellite has the orbital characteristics of the International Space Station. Communication in the network is based on TCP/IP over ATM, with the ABR service category providing the QoS, at OC-3 data rate. The OSPF protocol is used for routing. We simulate FTP file transfers, with the terrestrial site serving as the client and the LEO satellite being the server. The performance characteristics are presented.

  17. Prediction of fading phenomena in land-satellite communication links

    NASA Astrophysics Data System (ADS)

    Blaunstein, N.; Cohen, Y.; Hayakawa, M.

    2010-12-01

    This paper addresses the problem of prediction of probability of successful radio communication of any mobile or stationary subscriber located in areas of service such as complex urban environments characterized by nonline-of-sight propagation conditions, which limit GPS, Low Earth Orbit, and Medium Earth Orbit services in land-satellite communications. It presents a self-consistent physical-statistical approach for predicting fading phenomena usually occurring in land-satellite communication links caused by influence of the terrain features on radio signal propagation from the ground-based to the satellite antenna. This approach combines (1) the statistical description of the buildings array located on the rough terrain and the buildings' overlay profile, based on special probabilistic distributions of built-up terrain parameters, and (2) the theoretical description of propagation phenomena, taking into account multiple scattering, reflection, and diffraction mechanisms. A new technique is proposed for predicting the probability of fading phenomena occurring in land-satellite links using the so-called stochastic multiparametric model. Results of theoretical predictions are compared with those obtained from the "pure statistical" Lutz model and physical-statistical Saunders-Evans model, and then with experimental data obtained for different European cities. Obtained results show that the proposed stochastic approach can be used as a good predictor of fading phenomena in land-satellite communication links for different satellite constellation scenarios and elevations of satellites during their movement surrounding the Earth, with respect to the ground-based antenna for different land environments: rural, mixed residential, suburban, and urban.

  18. A Novel Communication Protocol and Delay Model for Networking Satellites

    Microsoft Academic Search

    Stevan Jovanovic; Ardian Greca

    2006-01-01

    Satellite systems, which can extend the communication of data and multimedia, have drawn a great enthusiasm in the research environment. These systems involve a large number of satellites communicating with each other via inter-satellite links for satellites in the same layer and via inter-orbital links between satellites in different layers. The system can be extended beyond the existing LEO, MEO

  19. Short Communication Satellite tracking highlights difficulties in the design

    E-print Network

    Exeter, University of

    Short Communication Satellite tracking highlights difficulties in the design of effective protected are concentrated near neritic breeding and nesting grounds. We used satellite telemetry to de- scribe patterns

  20. Turbo Decoder Development in Regenerative Communications Satellites

    Microsoft Academic Search

    B. Lestriez; E. R. Perez

    2006-01-01

    For regenerative telecom satellite systems, the turbo decoder has become a basic component of the on-board processing (OBP). This paper presents the algorithm selection choices and the test bench policy during the design process of a communication system critical block such as a turbo decoder compliant with the DVB-RCS standard (digital video broadcast-return channel satellite). The architecture, based on the

  1. MCPC system and terminal equipment for satellite communication

    Microsoft Academic Search

    T. Saruwatari; K. Yamada; T. Takahashi; S. Isobe; M. Iguchi; H. Ohashi; I. Nishiyama; S. Tsuchiya

    1982-01-01

    In a domestic satellite communication system, small capacity communication links using small-sized earth stations are required for thin routes. At Radio Research Laboratories, the Multi-Channel Per Carrier (MCPC), a small capacity satellite communication system, has been proposed and successfully developed in the Medium Capacity Communications Satellite for Experimental Purposes (CS) experimental project. The operation of the MCPC system is similar

  2. Mobile satellite communications systems: Toward global personal communications

    Microsoft Academic Search

    John H. Lodge

    1991-01-01

    The constraints imposed by the RF environment are reviewed. An overview of present and planned mobile satellite systems is given. Present systems refer to those already in operation, while planned systems refer to those that have authority to offer the services and have either a satellite in orbit or one being built to support the systems. Future directions for mobile

  3. A personal communications network using a Ka-band satellite

    NASA Technical Reports Server (NTRS)

    Palmer, Larry C.; Laborde, Enrique; Stern, Alan; Sohn, Philip Y.

    1992-01-01

    The feasibility of a personal communications network using portable terminals that can provide 4.8-kb/s voice communications to a hub station via a Ka-band geosynchronous satellite has been investigated. Tradeoffs are examined so that the combined system of hub and gateway earth stations, the satellite, and the personal terminals can provide a competitive service in terms of cost, availability, and quality. A baseline system that uses a spacecraft with approximately 140 spot beams to cover the contiguous US (CONUS) and 5-W power amplifiers in each beam is described. Satellite access in both the forward and return directions uses frequency-division multiple-access/code-division multiple-access (FDMA/CDMA) with a chip rate of 2.5 Mchip/s.

  4. Laser data links for communication satellites

    NASA Technical Reports Server (NTRS)

    Ohern, W. L.; Rodenberger, C. A.

    1974-01-01

    Laser data relays potentially offer continuous 1 Gb/sec bandwidths, drastically increasing low-altitude satellite data collection capacity over present store-and-dump techniques. Availability of the laser link as a reliable alternative, operating within conventional low-altitude communication subsystem weight and power allocations, will create customer pressure for adoption. Major communication relay system impacts are discussed including reliability, mechanical design, attitude control, on-board data handling, contamination control, and traffic-net management. Interface parameters which drive the fundamental relay satellite design concepts are discussed, and conditions requiring early quantitative analysis are identified.

  5. Optical communication systems for satellite applications

    NASA Astrophysics Data System (ADS)

    Suter, Joseph J.

    1999-07-01

    In conventional satellites, the RF and microwave signal transmissions between electronic modules are accomplished using waveguide or coaxial lines. Advances in fiber-optic technology have made it possible to modulate low-noise RF and microwave signal on fiber-optic distribution lines, resulting in weight and space savings. These optical communication systems enable intrasatellite communications among the electronic modules like transmitters, receivers, and clocks. This paper summarizes findings from several studies on the use of fiber-optic lines for RF/microwave signal transmission on-board satellites. It will also update some experimental results of prototype systems developed previously for intrasatellite signal distribution.

  6. ETS-VI multibeam satellite communications systems

    NASA Astrophysics Data System (ADS)

    Kawai, Makoto; Tanaka, Masayoshi; Ohtomo, Isao

    1989-10-01

    The fixed and mobile satellite communications systems of the Japanese Engineering Test Satellite-VI (ETS-VI) are described. The system requirements are outlined along with the system configuration. The ETS-VI multibeam system employs three frequency bands. When used for Ka-band fixed communications, it covers the Japanese main islands with thirteen 0.3-degree-wide spot beam. Four of the beams are active for ETS-VI. When used for S-band mobile communications, five beams cover the area within 200 nautical miles from the Japanese coast. The C-band beam for fixed communications covers the central area of the Japanese main islands with a single beam. The onboard antenna system is described along with the transponders and their associated onboard systems. A discussion of the system technology follows, covering the TDMA transmisssion system, the relay function, rainfall compensation, and the antenna and propagation performance.

  7. 25 Years of British military satellite communications

    Microsoft Academic Search

    Dennis Cummings CEng FIEE

    1993-01-01

    Next year sees the 25th anniversary of the birth of satellite communications since the launch in 1969 of Skynet 1. The intervening years have seen the advent of universal communications systems for both military and civilian purposes of increasing technical sophistication, to the extent that the 1991–92 Gulf War has been called the ‘first space war’. Here Dennis Cum?mings celebrates

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

    E-print Network

    Lohmeyer, Whitney Quinne

    In this work, we analyze a historical archive of single event upsets (SEUs) maintained by Inmarsat, one of the world's leading providers of global mobile satellite communications services. Inmarsat has operated its ...

  9. Innovative Networking Concepts Tested on the Advanced Communications Technology Satellite

    NASA Technical Reports Server (NTRS)

    Friedman, Daniel; Gupta, Sonjai; Zhang, Chuanguo; Ephremides, Anthony

    1996-01-01

    This paper describes a program of experiments conducted over the advanced communications technology satellite (ACTS) and the associated TI-VSAT (very small aperture terminal). The experiments were motivated by the commercial potential of low-cost receive only satellite terminals that can operate in a hybrid network environment, and by the desire to demonstrate frame relay technology over satellite networks. The first experiment tested highly adaptive methods of satellite bandwidth allocation in an integrated voice-data service environment. The second involved comparison of forward error correction (FEC) and automatic repeat request (ARQ) methods of error control for satellite communication with emphasis on the advantage that a hybrid architecture provides, especially in the case of multicasts. Finally, the third experiment demonstrated hybrid access to databases and compared the performance of internetworking protocols for interconnecting local area networks (LANs) via satellite. A custom unit termed frame relay access switch (FRACS) was developed by COMSAT Laboratories for these experiments; the preparation and conduct of these experiments involved a total of 20 people from the University of Maryland, the University of Colorado and COMSAT Laboratories, from late 1992 until 1995.

  10. Traffic model for advanced satellite designs and experiments for ISDN services

    NASA Technical Reports Server (NTRS)

    Pepin, Gerard R.; Hager, E. Paul

    1991-01-01

    The data base structure and fields for categorizing and storing Integrated Services Digital Network (ISDN) user characteristics is outlined. This traffic model data base will be used to exercise models of the ISDN Advanced Communication Satellite to determine design parameters and performance for the NASA Satellite Communications Applications Research (SCAR) Program.

  11. Designing Satellite Communication Networks by Zero-One Quadratic Programming

    E-print Network

    Helme, Marcia P.

    In satellite communications networks, distinctive facilities called homing stations perform special transmission functions. Local demand nodes clustered around each homing station communicate with each other via a local ...

  12. Multibeam active phased arrays for communications satellites

    Microsoft Academic Search

    A. Jacomb-Hood; E. Lier

    2000-01-01

    It is well known that an active phased array (APA) payload has the potential to overcome the flexibility limitations associated with conventional communications satellites. This article discusses the benefits and design drivers associated with APAs and features a deployed APA antenna architecture for multiple-beam applications that is modular in construction and programmable in performance. This architecture applies to both receive

  13. Laser satellite communications: current status and directions

    Microsoft Academic Search

    Geoffrey Hyde; Burton I. Edelson

    1997-01-01

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

  14. An experiment to enable commercial mobile satellite service

    NASA Technical Reports Server (NTRS)

    Lovell, R. R.; Knouse, G. H.; Weber, W. J.

    1982-01-01

    A Mobile Satellite Experiment (MSAT-X) is described, based on a planned cooperative U.S./Canadian program. The experiment would establish network architecture, develop system and ground-segment technology, and define the technical characteristics needed to help structure the regulatory/institutional framework needed to enable a first-generation commercial satellite service. A satellite of this type would augment terrestrial systems, both cellular and noncellular, in the thin-route/rural areas of the country where service is either unavailable or inadequate. Applications range from wide-area radio/dispatch (e.g., oil exploration and interstate trucking) to extension of the public mobile telephone service. Market estimates are provided and experiment objectives and requirements are delineated. The requirements are being developed in close coordination with the Department of Communications (DOC) of Canada and with industry and potential-user organizations. The paper closes with a development plan and milestone chart.

  15. Satellite communications systems move into the twenty-first century

    Microsoft Academic Search

    Leonard S. Golding

    1998-01-01

    This paper discusses the evolution of communication satellite systems and communications satellite technology from the 1960's\\u000a to the 1990's. The paper identifies the key attributes of satellite communications that has driven this evolution and now\\u000a drives the future directions such systems will take. The paper then discusses the future direction of communication satellite\\u000a systems including DBS, MSS, FSS and hybrid

  16. New trends in laser satellite communications: design and limitations

    Microsoft Academic Search

    J. Císar; O. Wilfert; F. Fanjul-Vélez; N. Ortega-Quijano; J. L. Arce-Diego

    2008-01-01

    Optical communications offer a capable alternative to radio frequency (RF) communications for applications where high data-rate is required. This technology is particularly promising and challenging in the field of future inter-satellite communications. The term laser satellite communications (LSC) stands for optical links between satellites and\\/or high altitude platforms (HAPs). However, optical links between an earth station and a satellite or

  17. MICHAELMATSON NOAA National Earth Satellite Service

    E-print Network

    Dozier, Jeff

    in the computation of sea sur- face temperature by providing corrections for at- mospheric water vapor and cloud by the computer-enhanced NOAA-6satellite image of the midwestem United States in Figure 1, the 3.8-pm dataMICHAELMATSON NOAA National Earth Satellite Service Washington, DC 20233 JEFFDOZIER Department

  18. WDM Polymer Substrate Mode Photonic Interconnects for Satellite Communications

    E-print Network

    Chen, Ray

    WDM Polymer Substrate Mode Photonic Interconnects for Satellite Communications Jian Liu Polar is an enabling technology for future satellite communications to increase capacity ofbandwidth and network-3]. Compared with RF satellite communications, they use much smaller antenna aperture size and consume less

  19. Satellite Communications David Hart, dhart@cis.ohio-state.edu

    E-print Network

    Jain, Raj

    Satellite Communications David Hart, dhart@cis.ohio-state.edu This paper is intended to give an overview of that methods of and uses for satellite communications, in addition to presenting recent trends Page Table of Contents Introductionq Basic Elementsq Various Uses of Satellite Communications

  20. ANALYSIS OF HANDOVER CHARACTERISTICS IN SHADOWED LEO SATELLITE COMMUNICATION NETWORKS

    E-print Network

    Sung, Dan Keun

    ANALYSIS OF HANDOVER CHARACTERISTICS IN SHADOWED LEO SATELLITE COMMUNICATION NETWORKS£ YOUNG HOON In the near future low earth orbit (LEO) satellite communication networks will partially substitute for fixed communication networks more than one satellite need to be simultaneously visible in order to hand over a call

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

    NASA Technical Reports Server (NTRS)

    Ichiyoshi, Osamu

    1990-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

  3. An Earth Orbiting Satellite Service and Repair Facility

    NASA Technical Reports Server (NTRS)

    Berndt, Andrew; Cardoza, Mike; Chen, John; Daley, Gunter; Frizzell, Andy; Linton, Richard; Rast, Wayne

    1989-01-01

    A conceptual design was produced for the Geosynchronous Satellite Servicing Platform (GSSP), an orbital facility capable of repairing and servicing satellites in geosynchronous orbit. The GSSP is a man-tended platform, which consists of a habitation module, operations module, service bay and truss assembly. This design review includes an analysis of life support systems, thermal and power requirements, robotic and automated systems, control methods and navigation, and communications systems. The GSSP will utilize existing technology available at the time of construction, focusing mainly on modifying and integrating existing systems. The entire facility, along with two satellite retrieval vehicles (SRV), will be placed in geosynchronous orbit by the Advanced Launch System. The SRV will be used to ferry satellites to and from the GSSP. Technicians will be transferred from Earth to the GSSP and back in an Apollo-derived Crew Transfer Capsule (CTC). These missions will use advanced telerobotic equipment to inspect and service satellites. Four of these missions are tentatively scheduled per year. At this rate, the GSSP will service over 650 satelites during the projected 25 year lifespan.

  4. Microscale diversity in satellite communications

    NASA Technical Reports Server (NTRS)

    Cardoso, J. C.; Safaai-Jazi, Ahmad; Stutzman, Warren L.

    1993-01-01

    Results from an investigation into a microscale diversity scheme for the purpose of mitigating attenuation due to tropospheric scintillations are presented. Data from an experiment using the 20 GHz Olympus satellite beacon were analyzed to evaluate the performance of short-baseline site-diversity systems. Results indicate that with a baseline separation of about 50 m the signals received by the main and diversity terminals become decorrelated. Examination of several high-scintillation events shows that such a diversity technique could substantially increase the uptime of low-power-margin VSAT systems. The performance of microscale diversity for several baseline separations is evaluated in terms of a parameter called diversity recovery. Applications and conditions under which microscale diversity performs best are addressed.

  5. An optimization model of communications satellite planning

    Microsoft Academic Search

    Amitava Dutta; Dasaratha V. Rama

    1992-01-01

    A mathematical planning model is developed to help make cost effective decisions on key physical and operational parameters, for a satellite intended to provide customer premises services. The major characteristics of the model are: (1) interactions and tradeoffs among technical variables are formally captured; (2) values for capacity and operational parameters are obtained through optimization; (3) effects of physical and

  6. Optical intersatellite links - Application to commercial satellite communications

    NASA Technical Reports Server (NTRS)

    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.

  7. The 30/20 GHz fixed communications systems service demand assessment. Volume 3: Appendices

    NASA Technical Reports Server (NTRS)

    Gabriszeski, T.; Reiner, P.; Rogers, J.; Terbo, W.

    1979-01-01

    The market analysis of voice, video, and data 18/30 GHz communications systems services and satellite transmission services is discussed. Detail calculations, computer displays of traffic, survey questionnaires, and detailed service forecasts are presented.

  8. Method for scrambling satellite communications

    NASA Technical Reports Server (NTRS)

    Brockman, Milton H. (Inventor)

    1992-01-01

    A secure communications system multiplexes segments of the information signal for keyed encoding and modulation onto a plurality of different carrier frequencies and/or polarizations, and transmits the encoded carriers to multi-channel signal summing receivers that decode the segments from all channels, to reassemble the information signal for use by authorized stations with a key. The use of the multi-channel link and the summing receiver allows the greatest number of different coding algorithms for accommodating the greatest number of discrete secure channels.

  9. Land mobile communications satellite mission (LAMOCOSAMIS) Task 1: Market study

    NASA Astrophysics Data System (ADS)

    1985-12-01

    Land mobile communication service demand in Europe and the Mediterranean basin in the years 1995-2005 was estimated. A traffic model was derived. There is an exploding demand for land mobile communications in Europe, with overwhelming preference for two way telephone services. The users survey shows a surprising lack of sensitivity to prices and tariffs, which widely contributed to the preeminence of the needs for telephone services. This demand justifies that every effort be made to develop as fast as possible a compatible pan-European terrestrial mobile system. If a large proportion of the needs may be satisfied by terrestrial mobile system solutions, the potential remaining needs for telephony, outside of the presently planned terrestrial mobile, which can be served only by satellite, even under the pessimistic economic scenario and high cost/tariff assumptions, requires a number of equivalent telephone circuits which cannot be achieved with available state of the art technology.

  10. Satellite Counseling Services: What Makes Them Go?

    ERIC Educational Resources Information Center

    Birch, Wade G.; And Others

    1974-01-01

    The decentralization of counseling services has become a major form of outreach on college campuses. This article describes the establishment of two such satellite services, one successful and the other comparatively unsuccessful based on the criterion of student usage. Applications of this form of outreach to other settings are also discussed.…

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

    Microsoft Academic Search

    Guoxiang Ai; Huli Shi; Haitao Wu; Zhigang Li; Ji Guo

    2009-01-01

    It is a long dream to realize the communication and navigation functionality in a satellite system in the world. This paper\\u000a introduces how to establish the system, a positioning system based on communication satellites called Chinese Area Positioning\\u000a System (CAPS). Instead of the typical navigation satellites, the communication satellites are configured firstly to transfer\\u000a navigation signals from ground stations, and

  12. Leveraging Commercial Communication Satellites to support the Space Situational

    NASA Astrophysics Data System (ADS)

    Deaver, T.

    The majority of USSTRATCOM detect and track requirements in the geosynchronous regime could be met via strategic placement of medium grade optical sensors on select geosynchronous satellites at relatively low cost in less than 48 months. An architecture which includes hosting SSA sensors on eight to ten commercial communication satellites could provide for highly accurate, timely and relatively inexpensive detect and track capabilities. The major factors considered when hosting any sensor on a commercial communications satellite are size, weight (mass) and power or SWAP. Additional sensor specific items must also be considered to form a complete feasibility analysis. These include data rate, mounting constraints, thermal balance, timing accuracy, and attitude stability requirements. All of these factors directly impact the cost and flexibility of hosting such a sensor on a geosynchronous communication satellite. By choosing a relatively light weight, low power consumption sensor which requires a small amount of bandwidth to transmit its data, the cost of hosting the sensor is kept to a minimum. Once the type of sensor or sensors is identified, the next step is to identify idea geosynchronous locations for the "hosted" sensors. Once these locations are identified, then one would identify a potential host which needs to be replaced within the desired timeframe. Once the host is identified, then the satellite owner / operator should be approached about hosting a "neighborhood" watch sensor aboard their spacecraft. Commercial satellites are routinely replaced based on age, lack of available station keeping fuel or to allow a service provider to upgrade its capabilities. Each commercial communication satellite operator maintains a plan of replacing spacecraft. Between the two largest commercial SATCOM providers, INTELSAT and SES, six to eight spacecraft will be replaced each year (100 plus spacecraft with 15 year average lifetimes). The satellites are usually procured, designed, built, launched and operational within 36 months. In order for the US Government to adapt to this timeline, a sensor specification would need to be established as well as a sensor procurement pipeline. The sensors would then be provided to the satellite bus manufacturer for integration onto the bus. The spacecraft would then be launched and operated by the commercial SATCOM operator for the life of the spacecraft. Based on this approach, it is highly conceivable that a complete geosynchronous "neighborhood" watch program could be completed within 48 months of initiation.

  13. Engineering calculations for communications satellite systems planning

    NASA Astrophysics Data System (ADS)

    Martin, C. H.; Gonsalvez, D. J.; Levis, C. A.; Wang, C. W.

    1983-12-01

    Progress is reported on a computer code to improve the efficiency of spectrum and orbit utilization for the Broadcasting Satellite Service in the 12 GHz band for Region 2. It implements a constrained gradient search procedure using an exponential objective function based on aggregate signal to noise ratio and an extended line search in the gradient direction. The procedure is tested against a manually generated initial scenario and appears to work satisfactorily. In this test it was assumed that alternate channels use orthogonal polarizations at any one satellite location.

  14. Intersatellite link application to commercial communications satellites

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

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

  15. Hispasat 1: A breakthrough in communications satellites

    NASA Astrophysics Data System (ADS)

    Garreau, Michel

    1991-10-01

    Principal features and background for the first generation of Hispasat space communications system approved in January 1989 by the Spanish government are presented. The development started in August 1989 and comprises two satellites and a Ground Control System (GCS). Details of the operational plan and spacecraft characteristics are given. The platform payload and main repeater equipment are described. The spacecraft operational aspects, mass budget, power budget, launcher, lifetime, development and procurement are considered.

  16. A New Era Begins: Satellite Communications and Development.

    ERIC Educational Resources Information Center

    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…

  17. Presentations of the Ninth Advanced Communications Technology Satellite Propagation Studies Workshop (APSW IX)

    NASA Technical Reports Server (NTRS)

    Golshan, Nasser (Editor)

    1997-01-01

    The Advanced Communications Technology Satellite Propagation Studies Workshop (APSW) is convened each year to present the results of the ACTS Propagation Campaign. Representatives from the satellite communications (satcom) industry, academia, and government are invited to APSW for discussions and exchange of information. The ACTS Propagation campaign is completing three years of Ka-Band data collection at seven sites in North America. Through this effort, NASA is making a major contribution to growth of satcom services by providing timely propagation data and models for predicting the performance of Ka-Band satellite communications systems.

  18. Spread spectrum synchronization for a LEO personal communications satellite system

    Microsoft Academic Search

    D. E. Dodds; M. Moher

    1995-01-01

    This paper investigates required signal structure and receiver code synchronization techniques for satellite based CDMA personal communications systems. A signal structure is proposed in which different CDMA codes are used to differentiate each satellite (as in the GPS system) and different phases of one code (as in the IS-95 standard) to differentiate spot beams on one satellite. Due to satellite

  19. A digitally implemented communications experiment utilizing the communications technology satellite, Hermes

    NASA Technical Reports Server (NTRS)

    Jackson, H. D.; Fiala, J.

    1980-01-01

    Developments which will reduce the costs associated with the distribution of satellite services are considered with emphasis on digital communication link implementation. A digitally implemented communications experiment (DICE) which demonstrates the flexibility and efficiency of digital transmission of television video and audio, telephone voice, and high-bit-rate data is described. The utilization of the DICE system in a full duplex teleconferencing mode is addressed. Demonstration teleconferencing results obtained during the conduct of two sessions of the 7th AIAA Communication Satellite Systems Conference are discussed. Finally, the results of link characterization tests conducted to determine (1) relationships between the Hermes channel 1 EIRP and DICE model performance and (2) channel spacing criteria for acceptable multichannel operation, are presented.

  20. Communications satellite systems operations with the space station. Volume 3: Supplementary technical report

    NASA Technical Reports Server (NTRS)

    Price, K. M.; Russell, P.; Weyandt, C.

    1988-01-01

    The NASA space station has the potential to provide significant economic benefits to commercial communications satellite operators. The initial reports qunatified the benefits of space-based activities and assessed the impacts on the satellite design and the space station. Results are given for the following additional tasks: quantify the value of satellite retrievability operations and define its operational aspects; evaluate the use of expendable launch vehicles for transportation of satellites from the Earth to the space station; and quantify the economic value of modular satellites that are assembled and serviced in space.

  1. A framework for implementing data services in multi-service mobile satellite systems

    NASA Technical Reports Server (NTRS)

    Ali, Mohammed O.; Leung, Victor C. M.; Spolsky, Andrew I.

    1988-01-01

    Mobile satellite systems being planned for introduction in the early 1990s are expected to be invariably of the multi-service type. Mobile Telephone Service (MTS), Mobile Radio Service (MRS), and Mobile Data Service (MDS) are the major classifications used to categorize the many user applications to be supported. The MTS and MRS services encompass circuit-switched voice communication applications, and may be efficiently implemented using a centralized Demand-Assigned Multiple Access (DAMA) scheme. Applications under the MDS category are, on the other hand, message-oriented and expected to vary widely in characteristics; from simplex mode short messaging applications to long duration, full-duplex interactive data communication and large file transfer applications. For some applications under this service category, the conventional circuit-based DAMA scheme may prove highly inefficient due to the long time required to set up and establish communication links relative to the actual message transmission time. It is proposed that by defining a set of basic bearer services to be supported in MDS and optimizing their transmission and access schemes independent of the MTS and MRS services, the MDS applications can be more efficiently integrated into the multi-service design of mobile satellite systems.

  2. Land vehicle antennas for satellite mobile communications

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

    Antenna designs applicable to future satellite mobile vehicle communications are examined. Microstrip disk, quadrifilar helix, cylindrical microstrip, and inverted V and U crossed-dipole low gain antennas (3-5 dBic) that provide omnidirectional coverage are described. Diagrams of medium gain antenna (9-12 dBic) concepts are presented; the antennas are classified into three types: (1) electronically steered with digital phase shifters; (2) electronically switched with switchable power divider/combiner; and (3) mechanically steered with motor. The operating characteristics of a conformal antenna with electronic beam steering and a nonconformal design with mechanical steering are evaluated with respect to isolation levels in a multiple satellite system. Vehicle antenna pointing systems and antenna system costs are investigated.

  3. Delta capability for launch of communications satellites

    NASA Technical Reports Server (NTRS)

    Grimes, D. W.; Russell, W. A., Jr.; Kraft, J. D.

    1982-01-01

    The evolution of capabilities and the current performance levels of the Delta launch vehicle are outlined. The first payload was the Echo I passive communications satellite, weighing 179 lb, and placed in GEO in 1960. Emphasis since then has been to use off-the-shelf hardware where feasible. The latest version in the 3924 first stage, 3920 second stage, and Pam D apogee kick motor third stage. The Delta is presently equipped to place 2800 lb in GEO, as was proven with the 2717 lb Anik-D1 satellite. The GEO payload placement performance matches the Shuttle's, and work is therefore under way to enhance the Delta performance to handle more massive payloads. Installation of the Castor-IV solid motor separation system, thereby saving mass by utilizing compressed nitrogen, rather than mechanical thrusters to remove the strap-on boosters, is indicated, together with use of a higher performance propellant and a wider nose fairing.

  4. Two-way time transfer via communication satellites

    Microsoft Academic Search

    Dieter Kirchner

    1991-01-01

    The history of two-way satellite time transfer is provided and developments in satellite communications technology conducive to this time transfer technique are briefly reviewed. The difference between one-way and two-way satellite time transfer is explained, and the advantages and disadvantages of the two-way method are pointed out. The theory of the two-way technique using geostationary communication satellites is presented showing

  5. Ka-band aeronautical satellite communications experiments using COMETS

    Microsoft Academic Search

    Amane Miura; Shinichi Yamamoto; Huan-Bang Li; Masato Tanaka; Hiromitsu Wakana

    2002-01-01

    This paper describes the results of evaluation tests of an aeronautical satellite communications experiments system in the Ka-band using Japan's communications and broadcasting engineering test satellite (COMETS). An active phased-array antenna with an open-loop satellite tracking capability operating in the Ka-band was installed just behind the passenger window of an airplane to receive a satellite signal. The propagation measurements showed

  6. 75 FR 71434 - Notice of Public Information Collection(s) Being Reviewed by the Federal Communications...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-23

    ...including communications and remote sensing satellite services...evaluate satellite operators...approval for communications activities...ascertain whether satellite operators...space for communications and...

  7. 78 FR 61348 - Information Collection Being Reviewed by the Federal Communications Commission Under Delegated...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-03

    ...including communications and remote sensing satellite services...evaluate satellite operators...approval for communications activities...ascertain whether satellite operators...space for communications and...

  8. 6 Channel PCM Sound Receiver For Japanese Communication Satellite Audio Broadcasting System

    Microsoft Academic Search

    Tomozo OHTA; Masao MIYAZAKI; Takamitsu KITAYAMA; Takahiro CHIHARA; Minoru KUBOTA; Yasuhiro HAMAGUCHI; Kazuhiro KISHIMOTO

    1992-01-01

    The 6 channel PCM sound receiver for Japanese Chi- - nUitlPiLXer -6 CS(Communication Satellite) audio broadcasting PCI High-quality PCM sound broadcasting service via CS in the 12 GHz band will be started soon in Japan. In this service, 6 channels of 2.048Mbps PCM sound signal are multiplexed by time division, and are broadcasted to home individually using one satellite transponder(l).

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

    Microsoft Academic Search

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

    1991-01-01

    This paper discusss the systems approach taken by NASA and the Jet Propulsion Laboratory in the commercialization of land-mobile satellite services (LMSS) in the United States. As the lead center for NASA's Mobile Satellite Program, JPL was involved in identifying and addressing many of the key barriers to commercialization of mobile satellite communications, including technical, economic, regulatory and institutional risks,

  10. 76 FR 17347 - Aviation Communications

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-29

    ...Aeronautical Mobile Satellite (Route) Service...air-to-air communications in Hawaii...Aeronautical Mobile Satellite (Route) Service...air-to-air communications in Hawaii...requiring that mobile satellite systems accord...to AMS(R)S communications in...

  11. On-board processing concepts for future satellite communications systems

    NASA Technical Reports Server (NTRS)

    Brandon, W. T. (editor); White, B. E. (editor)

    1980-01-01

    The initial definition of on-board processing for an advanced satellite communications system to service domestic markets in the 1990's is discussed. An exemplar system with both RF on-board switching and demodulation/remodulation baseband processing is used to identify important issues related to system implementation, cost, and technology development. Analyses of spectrum-efficient modulation, coding, and system control techniques are summarized. Implementations for an RF switch and baseband processor are described. Among the major conclusions listed is the need for high gain satellites capable of handling tens of simultaneous beams for the efficient reuse of the 2.5 GHz 30/20 frequency band. Several scanning beams are recommended in addition to the fixed beams. Low power solid state 20 GHz GaAs FET power amplifiers in the 5W range and a general purpose digital baseband processor with gigahertz logic speeds and megabits of memory are also recommended.

  12. Low cost satellite land mobile service for nationwide applications

    NASA Technical Reports Server (NTRS)

    Weiss, J. A.

    1978-01-01

    A satellite land mobile system using mobile radios in the UHF band, and Ku-band Communications Routing Terminals (earth stations) for a nationwide connection from any mobile location to any fixed or mobile location, and from any fixed location to any mobile location is proposed. The proposed nationwide satellite land mobile service provides: telephone network quality (1 out of 100 blockage) service, complete privacy for all the users, operation similar to the telephone network, alternatives for data services up to 32 Kbps data rates, and a cost effective and practical mobile radio compatible with system sizes ranging from 10,000 to 1,000,000 users. Seven satellite alternatives (ranging from 30 ft diameter dual beam antenna to 210 ft diameter 77 beam antenna) along with mobile radios having a sensitivity figure of merit (G/T) of -15 dB/deg K are considered. Optimized mobile radio user costs are presented as a function of the number of users with the satellite and mobile radio alternatives as system parameters.

  13. An advanced conceptual design study for a mobile satellite communications system

    NASA Astrophysics Data System (ADS)

    Salmasi, A. B.

    It is pointed out that a vast portion of the land mass, and a significant portion of the U.S. population in rural and remote areas, are deprived of most of the advanced telecommunication services offered in metropolitan areas. For the last decade, investigations have been conducted regarding the feasibility to provide telecommunication services throughtout the thinly populated areas with the aid of a geostationary satellite. The considered communication services are related to mobile and thin-route radiotelephony, wideband and narrowband data transmissions, and position location services. The mobile satellite (MSAT) communications system studied could provide a truly national and ubiquitous service. Attention is given to satellite antenna design, an MSAT link design analysis, and analysis results.

  14. Near Field Communication Network Services

    Microsoft Academic Search

    Jorma Ylinen; Mikko Koskela; Lari Iso-anttila; Pekka Loula

    2009-01-01

    Near Field Communication (NFC) provides means to close-range contactless identification and communication for mobile phones and other devices alike. NFC is a new technology but it is maturing fast as it is being standardized. The first NFC services have mostly been simple applications but with the expansion of NFC technology and its application areas there is an urgent need to

  15. NASA to launch second business communications satellite

    NASA Technical Reports Server (NTRS)

    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.

  16. Payload system tradeoffs for mobile communications satellites

    NASA Technical Reports Server (NTRS)

    Moody, H. J.

    1990-01-01

    System level trade-offs carried out during Mobile Satellite (M-SAT) design activities are described. These trade-offs relate to the use of low level beam forming, flexible power and spectrum distribution, and selection of the number of beams to cover the service area. It is shown that antenna performance can be improved by sharing horns between beams using a low level beam forming network (BFN). Additionally, greatly increased power utilization is possible using a hybrid matrix concept to share power between beams.

  17. FM-SCPC system and equipments for satellite communication

    Microsoft Academic Search

    S. Isobe; T. Saruwatari; M. Iguchi; H. Ohashi; S. Tsuchiya; I. Nishiyama; T. Takahashi

    1982-01-01

    It is planned that one of the K-band transponders of a Japanese communications satellite will be used for small traffic communications. In order to establish the small capacity communications system, the Signal Channel per Carrier (SCPC) system operating in 30\\/20 GHz band is being considered as part of the Medium Capacity Communications Satellite for Experimental Purposes (CS), and small-size earth

  18. Computer Communication Via Satellites--A Queueing Model

    Microsoft Academic Search

    BEZALEL GAVISH; ALAN G. KONHEIM

    1977-01-01

    The last few years have witnessed the intensive growth of computer communication networks. The need for nationwide and multination computer communication systems brought about the development of packet-switching networks such as the ARPANET. In this paper we examine a model for computer-to-computer communication via a satellite link. In each network, a single node, the satellite communication concentrator (SCC), manages the

  19. 47 CFR 73.667 - TV subsidiary communications services.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Telecommunication FEDERAL COMMUNICATIONS COMMISSION... BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES...TV subsidiary communications services...TV subsidiary communications services that...carrier or private radio in nature...

  20. 47 CFR 73.667 - TV subsidiary communications services.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Telecommunication FEDERAL COMMUNICATIONS COMMISSION... BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES...TV subsidiary communications services...TV subsidiary communications services that...carrier or private radio in nature...

  1. Utilization of L-band frequencies for the maritime mobile-satellite service

    Microsoft Academic Search

    A. Das; J. Gilsenan

    1975-01-01

    A portion of the L-Band frequencies has been allocated for the maritime mobile-satellite service. The advantages and disadvantages of using 1.6\\/1.5 GHz, 6\\/4 GHz and 14\\/11 GHz bands between land earth station and satellite are reviewed. A double-hop or an inter-satellite link would be necessary to complete some communications links and limited experiments show no deleterious effect of a double-hop

  2. Communications technology satellite: United States experiments and disaster communications applications

    NASA Technical Reports Server (NTRS)

    Donoughe, P.; Hunczak, H. R.; Gurski, G. S.

    1978-01-01

    Ground antennas from 0.6 to 5.0 meters in diameter were used as remote earth terminals by the United States for both wideband (television) and narrowband (voice, data) communication in conjunction with the Canadian Hermes satellite's high power transmitter. Experiments summarized cover teleconferencing and duplex videoconferencing for medical, educational, and civic purposes, as well as the remote interpretation of multilingual broadcasts from the United Nations. The capabilities of the system during real and simulated disasters at airports are assessed. Particular attention is given to miniexperiments for flood control in the Mississippi River basin and in Johnstown, Pennsylvania during the 1977 flood.

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

    ERIC Educational Resources Information Center

    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…

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

    ERIC Educational Resources Information Center

    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…

  5. FormSat, a scalable formation flying communication satellite system

    Microsoft Academic Search

    A. Braukhane; M. Arza; M. Bacher; M. Calaprice; H. Fiedler; V. Koehne; H. R. McGuire; J. J. Rivera

    2010-01-01

    The competitive and evolving nature of the commercial communications satellite market sector, combined with the limited number of allocations in geosynchronous orbit, have led to a steady increase in the complexity, size and weight of satellites. Satellite manufacturers in the sector have suffered from increased non-recurring engineering costs and low rate production, leading to insufficient profit margins. This paper identifies

  6. Rain Fade Compensation Alternatives for Ka Band Communication Satellites

    NASA Technical Reports Server (NTRS)

    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.

  7. Adaptive Beamforming in Mobile, Massively Multiuser Satellite Communications: A System

    E-print Network

    Gesbert, David

    Adaptive Beamforming in Mobile, Massively Multiuser Satellite Communications: A System Perspective Xiao Lei, Laura Cottatellucci, Samah A. M. Ghanem Mobile Communications Department, Eurecom, France Email: {xiao.lei; laura.cottatellucci; samah.ghanem}@eurecom.fr Abstract--We consider a Mobile Satellite

  8. Satellite communications systems and technology. Volume 2; Site Reports

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

    Volume 2 of the final report of the NASA/NSF Panel on Satellite Communications Systems and Technology is presented. It consists of the site reports from the panel's visits to satellite communications facilities and laboratories in Europe, Japan, and Russia.

  9. Main trends in satellite communication and broadcasting research

    Microsoft Academic Search

    Y. B. Zubarev; L. Y. Kantor

    1985-01-01

    The main advantages of satellite communication systems are possibility of multiple-call communication over a wide geographical zone, multistation access to a common satellite trunk resulting in a high utilization factor, formation of direct channels between any ground stations, commutation of floating channels in the time domain according to demand, and elimination of the distance between ground stations as a factor

  10. Research and development for international satellite communications in Japan

    Microsoft Academic Search

    A. Ogawa

    1984-01-01

    Major research and development activities for international satellite communications in Japan are introduced. Countermeasures against heavy rainfall-induced deterioration of communications signals, particularly for satellites above the Indian ocean, are addressed. These include results of studies on depolarization compensation for dual-polarized waves, and of a series of propagation experiments for determining the rain attenuation characteristics at 11 GHz for propagation paths

  11. On-board processing for future satellite communications systems: Satellite-Routed FDMA

    NASA Technical Reports Server (NTRS)

    Berk, G.; Christopher, P. F.; Hoffman, M.; Jean, P. N.; Rotholz, E.; White, B. E.

    1981-01-01

    A frequency division multiple access (FDMA) 30/20 GHz satellite communications architecture without on-board baseband processing is investigated. Conceptual system designs are suggested for domestic traffic models totaling 4 Gb/s of customer premises service (CPS) traffic and 6 Gb/s of trunking traffic. Emphasis is given to the CPS portion of the system which includes thousands of earth terminals with digital traffic ranging from a single 64 kb/s voice channel to hundreds of channels of voice, data, and video with an aggregate data rate of 33 Mb/s. A unique regional design concept that effectively smooths the non-uniform traffic distribution and greatly simplifies the satellite design is employed. The satellite antenna system forms thirty-two 0.33 deg beam on both the uplinks and the downlinks in one design. In another design matched to a traffic model with more dispersed users, there are twenty-four 0.33 deg beams and twenty-one 0.7 deg beams. Detailed system design techniques show that a single satellite producing approximately 5 kW of dc power is capable of handling at least 75% of the postulated traffic. A detailed cost model of the ground segment and estimated system costs based on current information from manufacturers are presented.

  12. The Future of Satellite Communications Technology.

    ERIC Educational Resources Information Center

    Nowland, Wayne

    1985-01-01

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

  13. Mugunghwa: The first Korean domestic satellite for FSS and DBS services

    NASA Astrophysics Data System (ADS)

    Hwangbo, Han

    Mugunghwa is the first generation satellite for the Republic of Korea. It uses the advanced digital technology for direct broadcasting and fixed satellite services in Korea. It will provide basic satellite communications facilities with small low-cost remote stations for rural and remote areas presently having inadequate or no telecommunication facilities. It will also provide high speed data and video distributions for business television and other professional program services such as tele-educational video networks. High quality color television and high definition TV services will also be available anywhere in Korea.

  14. Distributed Satellite Communication System Design: First-Order Interactions between System and Network

    E-print Network

    de Weck, Olivier L.

    Distributed Satellite Communication System Design: First-Order Interactions between System to bankruptcy. The upfront capital required to implement a satellite communications system is staggering and performance of a system. Traditionally, the first step toward designing satellite communication systems

  15. IEEE TRANSACTIONS ON COMMUNICATIONS, VOL. 46, NO. 3, MARCH 1998 309 Doppler Characterization for LEO Satellites

    E-print Network

    Al-Dhahir, Naofal

    when communicating through low earth orbit (LEO) satellites. This paper deals with the analytic approximation, satellite visibility. I. INTRODUCTION F OR SATELLITE communications through low earth orbit (LEOIEEE TRANSACTIONS ON COMMUNICATIONS, VOL. 46, NO. 3, MARCH 1998 309 Doppler Characterization

  16. What Drives Spacecraft Innovation? A Quantitative Analysis of Communication Satellite History

    E-print Network

    de Weck, Olivier L.

    1 What Drives Spacecraft Innovation? A Quantitative Analysis of Communication Satellite History of Communication Satellite History by Zoe Szajnfarber Submitted to the Department of Aeronautics tradeoffs associated with adopting this principle in the context of communication satellites

  17. INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING Int. J. Satell. Commun. Network. 2006; 24:261281

    E-print Network

    INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING Int. J. Satell. Commun. Network: 10.1002/sat.841 Turbo-coded APSK modulations design for satellite broadband communications Riccardo phase shift keying (APSK) modulation with application to satellite broadband communications. APSK

  18. Controlling satellite communication system unwanted emissions in congested RF spectrum

    NASA Astrophysics Data System (ADS)

    Olsen, Donald; Heymann, Roger

    2007-09-01

    The International Telecommunication Union (ITU), a United Nations (UN) agency, is the agency that, under an international treaty, sets radio spectrum usage regulations among member nations. Within the United States of America (USA), the organization that sets regulations, coordinates an application for use, and provides authorization for federal government/agency use of the radio frequency (RF) spectrum is the National Telecommunications and Information Administration (NTIA). In this regard, the NTIA defines which RF spectrum is available for federal government use in the USA, and how it is to be used. The NTIA is a component of the United States (U.S.) Department of Commerce of the federal government. The significance of ITU regulations is that ITU approval is required for U.S. federal government/agency permission to use the RF spectrum outside of U.S. boundaries. All member nations have signed a treaty to do so. U.S. federal regulations for federal use of the RF spectrum are found in the Manual of Regulations and Procedures for Federal Radio Frequency Management, and extracts of the manual are found in what is known as the Table of Frequency Allocations. Nonfederal government and private sector use of the RF spectrum within the U.S. is regulated by the Federal Communications Commission (FCC). There is a need to control "unwanted emissions" (defined to include out-of-band emissions, which are those immediately adjacent to the necessary and allocated bandwidth, plus spurious emissions) to preclude interference to all other authorized users. This paper discusses the causes, effects, and mitigation of unwanted RF emissions to systems in adjacent spectra. Digital modulations are widely used in today's satellite communications. Commercial communications sector standards are covered for the most part worldwide by Digital Video Broadcast - Satellite (DVB-S) and digital satellite news gathering (DSNG) evolutions and the second generation of DVB-S (DVB-S2) standard, developed by the European Telecommunications Standards Institute (ETSI). In the USA, the Advanced Television Systems Committee (ATSC) has adopted Europe's DVB-S and DVB-S2 standards for satellite digital transmission. With today's digital modulations, RF spectral side lobes can extend out many times the modulating frequency on either side of the carrier at excessive power levels unless filtered. Higher-order digital modulations include quadrature phase shift keying (QPSK), 8 PSK (8-ary phase shift keying), 16 APSK (also called 12-4 APSK (amplitude phase shift keying)), and 16 QAM (quadrature amplitude modulation); they are key for higher spectrum efficiency to enable higher data rate transmissions in limited available bandwidths. Nonlinear high-power amplifiers (HPAs) can regenerate frequency spectral side lobes on input-filtered digital modulations. The paper discusses technologies and techniques for controlling these spectral side lobes, such as the use of square root raised cosine (SRRC) filtering before or during the modulation process, HPA output power back-off (OPBO), and RF filters after the HPA. Spectral mask specifications are a common method of the NTIA and ITU to define spectral occupancy power limits. They are intended to reduce interference among RF spectrum users by limiting excessive radiation at frequencies beyond the regulatory allocated bandwidth.The focus here is on the communication systems of U.S. government satellites used for space research, space operations, Earth exploration satellite services (EESS), meteorological satellite services (METSATS), and other government services. The 8025 to 8400 megahertz (MHz) X band can be used to illustrate the "unwanted emissions" issue. 8025 to 8400 MHz abuts the 8400 to 8450 MHz band allocated by the NTIA and ITU to space research for space-to-Earth transmissions such as receiving very weak Deep Space Network signals. The views and ideas expressed in this paper are those of the authors and do not necessarily reflect those of The Aerospace Corporation or The National Oceanic and Atmosphe

  19. Advanced Communications Technology Satellite (ACTS): four-year system performance

    Microsoft Academic Search

    Roberto J. Acosta; Robert Bauer; Richard J. Krawczyk; Richard C. Reinhart; Michael J. Zernic; Frank Gargione

    1999-01-01

    The Advanced Communications Technology Satellite (ACTS) was conceived at the National Aeronautics and Space Administration (NASA) in the late 1970s as a follow-on program to ATS and CTS to continue NASA's long history of satellite communications projects. The ACTS project set the stage for the C-band satellites that started the industry, and later the ACTS project established the use of

  20. HR SERVICES COMMUNICATION SESSION

    E-print Network

    ;Completed Projects 2013 · Data Cleansing ­ ­ New Processes Implementation ­ Audit Reports · Core Upgrade Level Agreement · Recruitment KPIs · HRIS KPIs #12;HR Services Projects ­ 2013 DMS Core Data Cleansing

  1. Mass and power modeling of communication satellites

    NASA Technical Reports Server (NTRS)

    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.

  2. SAW based systems for mobile communications satellites

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

  4. RAPID COMMUNICATION / COMMUNICATION RAPIDE Results of pop-up satellite tagging of spawning

    E-print Network

    Hawai'i at Manoa, University of

    RAPID COMMUNICATION / COMMUNICATION RAPIDE Results of pop-up satellite tagging of spawning size bluefin tuna were captured in September and October 1997 and tagged and released with pop-up satellite pistées par satellite qui devaient se libérer de mars à juillet 1998. Dix-sept étiquettes ont bien été

  5. A network architecture for a geostationary communication satellite

    Microsoft Academic Search

    William D. Ivancic; M. J. Shalkhauser; J. A. Quintana

    1994-01-01

    An M-VSAT communication system envisioned by NASA would provide low data rate, direct-to-the-user communications services for interactive data, voice, facsimile, and video conferencing. Such a system would enhance current communications services and enable new services

  6. Personal communications via ACTS satellite HBR transponders

    NASA Technical Reports Server (NTRS)

    Fang, Russell J. F.

    1991-01-01

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

  7. Communication technology is integral to most aerospace systems. Communication satel-lites bring us live coverage of events from around the world, deep-space communication

    E-print Network

    Peraire, Jaime

    lacking terrestrial communication infrastructure, satellite-based networks provide the only viable mechanism for vital communication ser- vices. For example, the U.S. military depends on satellites for rapidly deployable, robust, and reliable communications during military operations, and satellites

  8. Emerging commercial opportunities based on combined communication navigation services

    NASA Astrophysics Data System (ADS)

    Gill, Eberhard; Fox, Brian M.; Kreisel, Joerg

    2006-07-01

    Cost reduction pressure on companies and increasing regulatory and legislative demand together with rapid technological progress in space-based communication and navigation are opening up new and exciting commercial opportunities. In this framework, a novel service for maritime applications is presented using a two-way messaging system and the global navigation satellite system (GNSS). The system implements an end-to-end solution for asset tracking and fleet management, positioning and tracing, messaging and security for all types of sea-going vessels. The service applies a vessel-based terminal hosting a GNSS receiver which transmits the navigation status together with messages to a Service Center with a flexible return-link capability. A hybrid space segment is considered comprising the Inmarsat constellation of geostationary communications satellites augmented by two highly inclined low earth orbit satellites for truly global services. Services will be offered to commercial enterprises such as fishing companies as well as public entities such as National Coast Guards. A detailed market analysis has been performed to assess these markets and to determine their penetration. Commercial viability has been proven for business models purely based on Inmarsat and a hybrid space segment using Inmarsat and dedicated micro-satellites. Both cases represent viable businesses in the range of MEUR 100 p.a. Although tailored to a specific market, the approach can be extended to other commercial opportunities requiring space-based communication-navigation services.

  9. Computer communications through telecommunications satellite systems - The NADIR project

    NASA Astrophysics Data System (ADS)

    Grange, J.-L.

    Current developments in satellite digital communication in Europe are surveyed, and the status of the French NADIR project begun in 1980 is reported. The geographic coverage, transmission rates, propagation delays, broadcasting and multidestination channels, and error rates characteristic of present satellite systems are discussed, and the specific performance parameters of the Telecom-1 system, comprising three geosynchronous satellites (one operational and two backup) with six 25-Mbit/sec, 12-14-GHz digital transponders and one 4-6 GHz analog port (for telephone and TV services) each, are examined. Telecom-1 will operate in a TDMA-AD mode with coverage of up to 320 earth stations in Central and Western Europe, transmission rates of 2.4-2000 kbit/sec, and error rates less than 10 to the -6th during 99 percent of the time. New applications foreseen include remote processing, distributed databases, computer teleconferencing, and electronic mail systems; new basic tools such as bulk-transfer and transaction-transfer protocols and database-management systems will be required. These tools are under development and testing (using the ANIS Telecom-1 simulator) by NADIR.

  10. Low cost Ku-band electronic steerable array antenna for mobile satellite communications

    Microsoft Academic Search

    Stefano Vaccaro; Daniel Llorens del Rio; Jose Padilla; Rens Baggen

    2011-01-01

    This paper presents the results of the development of an active phased array antenna for Ku-Band Receive-only mobile satellite communications realised within the ESA-project NATALIA. The phased array antenna is designed for mobile satellite services and dedicated for automotive applications. An overview of the complete build-up will be provided as well as the current status of the multilayer Printed Circuit

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

    NASA Technical Reports Server (NTRS)

    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.

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

    E-print Network

    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...

  13. DMSK Receiver For Mobile/Satellite Service

    NASA Technical Reports Server (NTRS)

    Davarian, Faramaz; Simon, Marvin K.; Sumida, Joe T.

    1989-01-01

    Receiver for 2.4-kbit/s differential minimum-shift keying (DMSK) and Gaussian minimum-shift keying(GMSK) suitable for communication between land-mobile stations via geostationary satellites. Operating on phase-shifted signal in 800-MHz band, in presence of fading and Doppler frequency shifts, receiver compact, makes efficient use of frequency spectrum, and wastes little power. Receiver design implemented in very-large-scale-integrated circuits. Basic DMSK receiver design relies on baseband rather than intermediate-frequency processing of in-phase and quadrature signal components because phase errors due to differential delays smaller at baseband.

  14. Design and analysis of the satellite laser communications network

    NASA Astrophysics Data System (ADS)

    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-?) 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.

  15. Communication flows during financial service innovation

    Microsoft Academic Search

    A. Lievens; R. K. Moenaert

    2001-01-01

    Reports on research concerning the role and nature of communication during the innovation process of new financial services. A causal framework has been developed on the antecedent role of communication in financial service innovation and its impact on success. Project team communication is conceptualized by: intra-project communication (communication between project team members); and extra-project communication (boundary-spanning communication). Examines the effectiveness

  16. Satellite servicing mission preliminary cost estimation model

    NASA Technical Reports Server (NTRS)

    1987-01-01

    The cost model presented is a preliminary methodology for determining a rough order-of-magnitude cost for implementing a satellite servicing mission. Mission implementation, in this context, encompassess all activities associated with mission design and planning, including both flight and ground crew training and systems integration (payload processing) of servicing hardward with the Shuttle. A basic assumption made in developing this cost model is that a generic set of servicing hardware was developed and flight tested, is inventoried, and is maintained by NASA. This implies that all hardware physical and functional interfaces are well known and therefore recurring CITE testing is not required. The development of the cost model algorithms and examples of their use are discussed.

  17. A Hybrid Satellite-Terrestrial Approach to Aeronautical Communication Networks

    NASA Technical Reports Server (NTRS)

    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.

  18. Satellite Packet Communication--Multiple Access Protocols and Performance

    Microsoft Academic Search

    S. Lam

    1979-01-01

    Satellite communication systems have traditionally been designed for voice traffic. Multiple access protocols for conflict resolution have typically been channel-oriented with either fixed or demand assignment. Data communications, however, have much more diverse traffic characteristics and transmission requirements than voice communications. We present in this paper an overview of two major categories of packet-oriented multiple access protocols: contention and reservation

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

    NASA Technical Reports Server (NTRS)

    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.

  20. A satellite system for land-mobile communications in Europe

    NASA Astrophysics Data System (ADS)

    Bartholome, P.; Rogard, R.

    1988-05-01

    There exists a great unsatisified demand for land mobile communications in Europe, particularly in sectors of business activity such as the road transport industry. This demand could best be satisfied by means of satellite-based private networks providing voice and data communications in a hub configuration. The potential market is estimated to encompass several hundred thousand road vehicles and the transmission capacity required would be several thousand channels. ESA is currently demonstrating the potential of satellite communications for this type of application, using a system called PRODAT. System studies are being performed with the aim of defining the architecture of a regional satellite system for Europe.

  1. Communicating Services Brands' Values Internally and Externally

    Microsoft Academic Search

    Leslie De Chernatony; Susan Cottam; Susan Segal-Horn

    2006-01-01

    This paper explores the ways that services brand values are communicated to both staff and customers. Values are communicated to employees via overt internal communications, the ripple effect, senior management example\\/involvement, HR activities and external communications. A number of failure factors which could hinder the communication of values to employees are identified. For consumers, values are communicated via their holistic

  2. Telecommunication service by leased transponders of the regional satellite

    NASA Astrophysics Data System (ADS)

    Jordan, Andrew

    Various telecommunications applications and services that can be provided by regional satellites are discussed. The potential for extending and enhancing Asia's telecommunications infrastructure is huge; and as Asian countries further develop economically, they will require the speed and power of satellites in order to develop their telecom and television broadcasting facilities quickly and economically. Topics discussed include emergence of regional satellite systems; services offered by regional satellites; rural telecommunication; trunk routes; international links; and television broadcasting.

  3. Mobile communications satellite antenna flight experiment definition

    NASA Astrophysics Data System (ADS)

    Freeland, Robert E.

    There are classes of application that collectively require a variety of different types of large-aperture space antennas. Fortunately, there are a number of different deployable antenna concepts that have tremendous potential for such applications. However, these concepts vary in maturity from flight-proven designs to extremely innovative configuration definitions. But these promising concepts lack sufficient demonstrations of maturity to be seriously considered in the large size range for immediate application. The reason for this situation is an extremely limited space flight data base in addition to the technical limitations and great costs associated with meaningful ground testing of large, flexible, precision space structures. The user community of such structures, especially the commercial organizations interested in providing a Mobile Communications Satellite (MSAT) on a profit-making basis, will require significant demonstrations of technology readiness prior to application commitment. Such demonstrations will probably be based on a combination of extensive ground testing and subsequent space flight experiments. The Communications Division of the National Aeronautics and Space Administration (NASA) Office of Space Science and Applications sponsored a study at the Jet Propulsion Laboratory (JPL) to determine the technical feasibility and cost of a Shuttle-based flight experiment specifically intended for the MSAT commercial user community. The experiment will include demonstrations of technology in the areas of radio frequency (RF), sensing and control, and structures. This paper summarizes the results of the structural subsystem study. These results include experiment objective and technical approach, experiment structural description, structure/environment interactions, structural characterization, thermal characterization, structural measurement system, and experiment functional description.

  4. Space transportation, satellite services, and space platforms

    NASA Technical Reports Server (NTRS)

    Disher, J. H.

    1979-01-01

    The paper takes a preview of the progressive development of vehicles for space transportation, satellite services, and orbital platforms. A low-thrust upper stage of either the ion engine or chemical type will be developed to transport large spacecraft and space platforms to and from GEO. The multimission spacecraft, space telescope, and other scientific platforms will require orbital serves going beyond that provided by the Shuttle's remote manipulator system, and plans call for extravehicular activity tools, improved remote manipulators, and a remote manned work station (the cherry picker).

  5. Application of advanced on-board processing concepts to future satellite communications systems

    NASA Technical Reports Server (NTRS)

    Katz, J. L.; Hoffman, M.; Kota, S. L.; Ruddy, J. M.; White, B. F.

    1979-01-01

    An initial definition of on-board processing requirements for an advanced satellite communications system to service domestic markets in the 1990's is presented. An exemplar system architecture with both RF on-board switching and demodulation/remodulation baseband processing was used to identify important issues related to system implementation, cost, and technology development.

  6. Beyond the Ionosphere: Fifty Years of Satellite Communication

    NASA Technical Reports Server (NTRS)

    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. Continuation of the compendium of applications technology satellite and communications technology satellite user experiments 1967-1977, volume 2. [bibliography

    NASA Technical Reports Server (NTRS)

    Engler, N. A.; Nash, J. F.; Strange, J. D.

    1978-01-01

    Approximately 453 reports, papers, and articles catalogued into an information retrieval system, covering communications experiments and demonstrations conducted, utilizing the Communications Technology Satellite and the Applications Technology Satellites 1, 3, 5, and 6 are listed.

  8. Aeronautical mobile satellite service: Air traffic control applications

    NASA Technical Reports Server (NTRS)

    Sim, Dave

    1990-01-01

    Canada's history both in aviation and in satellite communications development spans several decades. The introduction of aeronautical mobile satellite communications will serve our requirements for airspace management in areas not served by line-of-sight radio and radar facilities. The ensuing improvements in air safety and operating efficiency are eagerly awaited by the aviation community.

  9. Dynamic resource allocation DAMA alternatives study for satellite communications systems

    E-print Network

    Yao, Huan

    We consider the design of demand assigned multiple access (DAMA) algorithms that efficiently utilize limited RF uplink resources for packet switched military satellite communication networks. In previous work, we designed ...

  10. Bandwidth Efficient Turbo Coding For High Speed Mobile Satellite Communications

    Microsoft Academic Search

    Mark Rice; Paul Gray; S. Adrian Barbulescu; Wade Farrell

    1997-01-01

    ABSTRACT This paper describes an application of turbo codes in conjunction with 16QAM in high speed mobile satellite communications The channel characteristics, the architecture of the modem and the performance curves for the selected turbo codes are presented

  11. An advanced system design for future global mobile satellite communications

    Microsoft Academic Search

    Hideo Okinaka; Yasuo Hirata

    1986-01-01

    This paper presents a system concept applicable to the future global mobile satellite communications system. The main features of the proposed system are a demand-assigned beam-hopping TDMA operation in the satellite-to-mobile direction and a demand-assigned SCPC operation in the mobile-to-satellite direction. A beam-hopping repeater configuration which does not require a dynamic switch between transmitters and a multiple spot beam antenna

  12. Palapa-B communications satellite launched from the Shuttle Challenger

    NASA Technical Reports Server (NTRS)

    1983-01-01

    The Indonesian Palapa-B communications satellite is just about to clear the vertical stabilizer of the shuttle Challenger as it moves into its orbit. Also visible are the shuttle pallet satellite, the experiment package for NASA's Office of Space and Terrestrial Applications (OSTA-2), the now vacated cradles for Palapa and Telsat Canada's Anik C2 satellites, some getaway special (GAS) canisters and the Canadian-built remote manipulator system (RMS) arm.

  13. Power beaming to communication satellites in GEO

    NASA Astrophysics Data System (ADS)

    Morgan, R. M.; Lipinski, R. J.

    Batteries normally provide power to geosynchronous satellites during earth eclipse 90 times each year, but the heavy charge-discharge cycle decreases their life expectancy. Battery life, and thus satellite life, could be extended by providing power during eclipses via laser illumination of the photovoltaic array. For a spin-stabilized satellite this would require 35 kill using an 8-m diameter transmission mirror (and 850-nm light) or 180 kW using a 3.5-m mirror. A 3-axis stabilized satellite has a larger span and requires an elongated spot to use a comparable laser. At present, 70 satellites are scheduled to be replaced by the year 2000 at a cost of almost $10 billion. Power beaming could save a substantial portion of this cost. Laser illumination also could augment solar power to increase the power available to new satellites. Increased power could boost the signal strength or allow more channels on the satellite. In addition, high-frequency channels (which require higher power to penetrate the atmosphere) could be used. Removal of waste heat from the satellite limits the amount of power that can be transmitted. Nevertheless, a spin-stabilized satellite with power beaming could generate 0.9 kill per square meter of the collector array, which is six times that of an equivalent conventional satellite using the same size solar panel. A 3-axis stabilized satellite could generate 0.6 kW/sq m (four times conventional).

  14. Optimal energy allocation and admission control for communications satellites

    Microsoft Academic Search

    Alvin C. Fu; Eytan Modiano; John N. Tsitsiklis

    2003-01-01

    We address the issue of optimal energy allocation and admission control for communications satellites in earth orbit. Such satellites receive requests for transmission as they orbit the earth, but may not be able to serve them all, due to energy limitations. The objective is to choose which requests to serve so that the expected total reward is maximized. The special

  15. Optimal Energy Allocation and Admission Control for Communications Satellites

    Microsoft Academic Search

    Alvin Fu; Eytan Modiano; John N. Tsitsiklis

    2002-01-01

    We address the issue of optimal energy allocation and admis- sion control for communications satellites in earth orbit. These satellites receive requests for transmission as they orbit the earth, but may not be able to serve them all, due to energy limitations. The objective is to choose which requests to serve so that the expected total reward is maximized. The

  16. Computer-Aided Communication Satellite System Analysis and Optimization.

    ERIC Educational Resources Information Center

    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…

  17. Analysis of submarine cable and communication satellite systems reliabilities

    Microsoft Academic Search

    G. S. Li

    1977-01-01

    The performance of AT&T's overseas message telephone circuits for the years 1970-1975 was the basis for ana analysis of the reliability of submarine cables and communication satellite systems. Data presented in 24 tables is devided into three categories: (1) over cable and satellite system outage statistics for each of the six years and the six year average, (2) detailed cable

  18. Advanced technology in satellite communication antennas: Electrical and mechanical design

    Microsoft Academic Search

    Takashi Kitsuregawa

    1990-01-01

    Antenna technology for earth stations and satellites is discussed. The fundamentals, including common analysis methods, for antenna technology for satellite communication are reviewed. Details of the analysis method for beam waveguide feeds are shown, and electrical and mechanical designs for earth station antennas are examined. Offset dual-reflector antennas and offset reflector antennas with beam waveguide feed are examined, giving comprehensive

  19. Channel-Individual Adaptive Beamforming for Mobile Satellite Communications

    Microsoft Academic Search

    Thomas Gebauer; Heinz G. Göckler

    1995-01-01

    A digital frequency-division multiplex demultiplexer for single channel per carrier (SCPC) signals was developed for use in a digital channel-individual beamforming network for an adaptive satellite array antenna for mobile satellite communications. The available ASIC (35000 gate functions in CMOS technology, clock rate up to 30 MHz with low power consumption) permits the separation of FDM signals comprising up to

  20. The optimization location of communication and broadcasting satellite

    Microsoft Academic Search

    Gu Ningjiang; Gu Longxiang

    1991-01-01

    The optimal location of communication and broadcasting satellites in a static satellite orbit is discussed. Every country should choose the most advantageous orbit location on the limited arc-sector so that the loss of power flux density in its particular area will be lower, the receiving elevation will be higher, the receiving effect will be better, and the user's cost will

  1. Adaptive power control for satellite to ground laser communication

    Microsoft Academic Search

    Michael Gubergrits; Roman E. Goot; Uri Mahlab; Shlomi Arnon

    2007-01-01

    We develop an adaptive power control algorithm to facilitate satellite to ground laser communication through turbulence fading channels. Adaptive control is a powerful tool that improves energetic gain of the satellite laser. We use discrete laser transmitter intensity levels in our control algorithm. A novel recursive technique defines optimal laser transmitting intensity levels so that the laser-transmitted power is adapted

  2. IRECIN Nano-satellite communication system and ground segment

    Microsoft Academic Search

    M. Ferrante; M. Povia; L. Di Ciolo; A. Ortenzi; M. Petrozzi

    2005-01-01

    On board resources necessary to perform the mission tasks are very limited in nano-satellites. This paper proposes a real-time multi-processing system for the communication system between ground segment and IRECIN nano-satellite.The first microprocessor is devoted to interface to the rice-transceiver subsystem decoding packet information and the second one is in charge to communicate with the other subsystems through I2C bus.

  3. HTTP Performance Analysis over Multi-Hops Satellite Communication System

    Microsoft Academic Search

    Hiroyasu Obata; Kenji Ishida; Junichi Funasaka; Satoru Takeuchi; Kouichi Hirose; Katsuyuki Yamazaki

    2004-01-01

    In order to provide a long distance communication such as the one between two nodes separated by about halfway around the earth, a multi-hops satellite communication system which goes through multiple satellites is attractive. Furthermore, in case of disasters, the system is useful as the alternative to submarine optical fiber links. HTTP1.1 (HyperText Transfer Protocol version 1.1) is one of

  4. Spacecraft IF switch matrix for wideband service applications in 30/20 GHz communications satellite systems: Proof-of-concept model, executive summary

    NASA Technical Reports Server (NTRS)

    Ho, P. T.; Coban, E.; Pelose, J.

    1983-01-01

    The design and development of a unique coupler crossbar 20 x 20 microwave switch matrix are described. The test results of the proof of concept model that meets the requirements for a high speed satellite switched, time division multiple access (SS-TDMA) system are presented.

  5. Hybrid system of communication and positioning determination using two geostationary satellites

    NASA Astrophysics Data System (ADS)

    Morikawa, Eihisa; Matsumoto, Yasushi; Ohmori, Shingo; Wakao, Masayoshi

    1991-04-01

    A new hybrid satellite system has been developed which can provide both communications and positioning services in one system using two geostationary satellites. The first distinctive feature is that location information can be provided by transmitting and receiving ranging signals over the same channel that is used for voice communication employing two geostationary satellites. The second is that the frequency bandwidth of the system is very narrow compared with those of the GPS (Global Positioning System) and GEOSTAR. The experimental system, equipment configuration, and positioning accuracy are discussed. The dominant error factor of position determination was found to be the tracking error of the delay-lock loop of a receiver, and it was estimated to be several meters and several tens of meters in the spread-spectrum and single-channel-per-carrier systems, respectively. Taking account of satellite motions of ETS-V and INMARSAT, a positioning accuracy of several hundreds of meters was found in Pacific Ocean areas.

  6. Engineering calculations for communications satellite systems planning

    NASA Technical Reports Server (NTRS)

    Walton, E.; Aebker, E.; Mata, F.; Reilly, C.

    1991-01-01

    The final phase of a satellite synthesis project is described. Several methods for generating satellite positionings with improved aggregate carrier to interference characteristics were studied. Two general methods for modifying required separation values are presented. Also, two methods for improving aggregate carrier to interference (C/I) performance of given satellite synthesis solutions are presented. A perturbation of the World Administrative Radio Conference (WARC) synthesis is presented.

  7. Power beaming to communication satellites in GEO

    Microsoft Academic Search

    R. M. Morgan; R. J. Lipinski

    1992-01-01

    Batteries normally provide power to geosynchronous satellites during earth eclipse 90 times each year, but the heavy charge-discharge cycle decreases their life expectancy. Battery life, and thus satellite life, could be extended by providing power during eclipses via laser illumination of the photovoltaic array. For a spin-stabilized satellite this would require 35 kill using an 8-m diameter transmission mirror (and

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

    ERIC Educational Resources Information Center

    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…

  9. Impact of GOES satellites on the National Weather Service

    Microsoft Academic Search

    Elbert W. Friday

    1996-01-01

    The geostationary weather satellites are a critical component of the National Weather Service operations and on going nation wide modernization program. Geostationary satellites, because of their ability to constantly image the Earth, are important tools for observing severe weather such as hurricanes, severe thunderstorms, flash floods and winter storms. When satellite data are combined with other observing technologies such as

  10. Satellite communication and navigation for mobile users

    NASA Technical Reports Server (NTRS)

    Bernstein, S. L.

    1972-01-01

    Efforts made to utilize space technology for solving communication and navigation problems faced by mobile users in earth orientated situations are outlined. Applications include transoceanic airline communications, reliable long range ship-shore communications, emergency communications in regions with rough terrain, and military operations.

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

    ERIC Educational Resources Information Center

    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…

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

    ERIC Educational Resources Information Center

    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…

  13. Advanced Communications Technology Satellite (ACTS): Four-Year System Performance

    NASA Technical Reports Server (NTRS)

    Acosta, Roberto J.; Bauer, Robert; Krawczyk, Richard J.; Reinhart, Richard C.; Zernic, Michael J.; Gargione, Frank

    1999-01-01

    The Advanced Communications Technology Satellite (ACTS) was conceived at the National Aeronautics and Space Administration (NASA) in the late 1970's as a follow-on program to ATS and CTS to continue NASA's long history of satellite communications projects. The ACTS project set the stage for the C-band satellites that started the industry, and later the ACTS project established the use of Ku-band for video distribution and direct-to-home broadcasting. ACTS, launched in September 1993 from the space shuttle, created a revolution in satellite system architecture by using digital communications techniques employing key technologies such as a fast hopping multibeam antenna, an on-board baseband processor, a wide-band microwave switch matrix, adaptive rain fade compensation, and the use of 900 MHz transponders operating at Ka-band frequencies. This paper describes the lessons learned in each of the key ACTS technology areas, as well as in the propagation investigations.

  14. Computer Modeling and Simulation of Communications Satellite Channels

    Microsoft Academic Search

    LARRY C. PALMER

    1984-01-01

    Computer modeling of satellite communications channels is a valuable adjunct to analytical modeling and hardware simulation for predicting and verifying communications link performance. In the computer simulation approach, sampled signals are created in the computer and operated on by algorithms that simulate the effects of filtering, channel nonlinearities, interference, and noise. After passage through the simulated channel, the distorted signals

  15. An overview of the communications technology satellite project: Executive summary

    NASA Astrophysics Data System (ADS)

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

    1982-12-01

    An overview of the Communications Technology Satellite (CTS) project, a joint venture between NASA and the Canadian Department of Communications is given. A brief technical description of the CTS spacecraft and its cognate hardware and operations, a history of the CTS project, and a list of the CTS experiments and demonstrations conducted during the course of the project are given.

  16. A digital transmission system for global maritime satellite communications

    Microsoft Academic Search

    Y. Hirata; Y. Yasuda; H. Okinaka; K. Kashiki

    1984-01-01

    A digital transmission system for global maritime satellite communications has been designed, and experimental communications equipment has been developed, taking account of its potential application to the Inmarsat system where analog modulation is currently used for telephone signal transmission. This paper discusses possible digital technologies to realize an efficient digital transmission system, and presents a concept for the designed system.

  17. An overview of the communications technology satellite project: Executive summary

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

    An overview of the Communications Technology Satellite (CTS) project, a joint venture between NASA and the Canadian Department of Communications is given. A brief technical description of the CTS spacecraft and its cognate hardware and operations, a history of the CTS project, and a list of the CTS experiments and demonstrations conducted during the course of the project are given.

  18. Power Control Algorithms for Satellite Communication Systems

    Microsoft Academic Search

    A. Ince; D. Brown; J. Midgley

    1976-01-01

    Three different ground terminal transmit power control concepts for a Satcom system are examined. The effectiveness of constant satellite power (CSP) sharing among the carriers and adaptive satellite power (ASP) sharing is compared with constant ground terminal transmit power (CTP). It is shown that ASP offers substantial advantages over CSP in combating environmental degradations and that both can increase link

  19. EHF (28/19 GHz) personal communications satellite terminal development

    NASA Technical Reports Server (NTRS)

    Pike, Corey

    1991-01-01

    The concept of communicating on a personal basis using a small terminal has been investigated globally from many different applications and technology perspectives. Applications range from terrestrial handheld communicators for paging, cellular, zone voice/data networks, etc., to satellite terminals of pocket dimensions for voice/low speed data or similar terminals using larger antennas for VSAT, news gathering (30 cm), and video (1.2 m). A brief status of some developments in the satellite personal communications at CRC will be presented.

  20. AeroTCP: A Splitting Transport Protocol for an IP-based Satellite Network Supporting Aeronautical Communications

    E-print Network

    Baras, John S.

    Communications Yadong Shang* , Michael Hadjitheodosiou and John Baras Center for Satellite & Hybrid Communication to establish broadband aeronautical communication networks. Satellite network is recognized as one- ocean coverage. The expected advantages of the satellite systems for aeronautical communications also

  1. 47 CFR 90.371 - Dedicated short range communications service.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...false Dedicated short range communications service. 90.371 Section...Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) ...for Dedicated Short-Range Communications Service (dsrcs) §...

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

    NASA Astrophysics Data System (ADS)

    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 satellite communication systems. Therefore, the experimental DBF network with 16 radiating elements was developed for confirming a basic signal processing performance. A/D sampled data are processed by using FPGA circuit for beam forming by real-time basis. Optical Inter-Satellite Link Technology: The inter-satellite link (ISL) technology is also important, because the inter-satellite network is essential to realize the low delay network connection for multimedia services. The optical ISL simulator was developed for the study of optical modem and optical tracking mechanism. And the sensitivity of 56 photons/bit at 10-9 of error rate has been achieved by employing the Erbium doped fiber amplifier, polarizing filter and narrow band optical filter. Coude path type, the active universal joint (AUJ) type and two flat mirror type of optical antenna mechanism were developed. Satellite Network Technology: For constructing this optical ISL ring, the utilization of wavelength division multiplexing (WDM) technology is envisaged. By applying WDM technology to the optical intra-orbital ISL, logical mesh connections can be achieved by assigning the appropriate wavelength for the links among satellites. By using inclined orbit, inter-orbital ISL connection can be keep continuously. Therefore, WDM technology is also applicable to the inter-orbital ISL network. The satellite ATM network simulator was developed in order to investigate the effect of delay fluctuation caused by the satellite constellations. This simulator works as real-time basis by using commercial ATM switches and personal computers. This simulator was installed Dijkstra's algorithm to determine satellite routing path in order to minimize the end-to-end delay time from the source terminal to the destination terminal. The satellite IP network simulator has been developed in order to evaluate the congestion of the multimedia traffic. Variable Rate Modulation Technology: Considering the propagation impairments in the mobile conditions, we employ the variable rate transmission, which maintains the communication service

  3. A New Satellite Communication System Integrated into Public Switched Networks. - DYANET

    Microsoft Academic Search

    Masahumi Ohnuki; Masahiro Umehira; Hiroshi Nakashima; Shuzo Kato

    1992-01-01

    A system concept of a common alternative routing system is proposed for reducing total network costs by integrating satellite communications into public-switched networks, where satellite systems carry overflow traffic from terrestrial systems through common satellite channels. This concept has been realized by a satellite communication system called DYANET (dynamic channel assigning and routing satellite aided digital networks), which provides trunk

  4. Performance-aware Security of Unicast Communication in Hybrid Satellite Networks

    E-print Network

    Baras, John S.

    Performance-aware Security of Unicast Communication in Hybrid Satellite Networks Ayan Roy for securing the end-to-end communication in hybrid satellite networks. Satellite networks use TCP and HTTP communication in hybrid satellite networks. We therefore propose the use of the Layered IPSEC (LES) protocol

  5. Proof of concept effort for demonstrating an all-digital satellite communications earth terminal

    Microsoft Academic Search

    H. Beljour; R. Hoffmann; G. Michael; W. Schoonveld; J. Shields; I. Sumit; C. Swenson; A. Willson; T. Curtis; V. Weerackody

    2010-01-01

    The Space and Terrestrial Communications Directorate of the U.S. Army's Communications- Electronics Research, Development and Engineering Center is executing a proof of concept program to develop and demonstrate an All-Digital Satellite Communications Earth Terminal. The Future Advanced Satellite Terminal (FAST) program initially focuses on the satellite terminal's receive component of the satellite link. The two main efforts under FAST are

  6. Broadband and scalable mobile satellite communication system for future access networks

    NASA Astrophysics Data System (ADS)

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

    2005-07-01

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

  7. Satellites vs. fiber optics based networks and services - Road map to strategic planning

    NASA Astrophysics Data System (ADS)

    Marandi, James H. R.

    An overview of a generic telecommunications network and its components is presented, and the current developments in satellite and fiber optics technologies are discussed with an eye on the trends in industry. A baseline model is proposed, and a cost comparison of fiber- vs satellite-based networks is made. A step-by-step 'road map' to the successful strategic planning of telecommunications services and facilities is presented. This road map provides for optimization of the current and future networks and services through effective utilization of both satellites and fiber optics. The road map is then applied to different segments of the telecommunications industry and market place, to show its effectiveness for the strategic planning of executives of three types: (1) those heading telecommunications manufacturing concerns, (2) those leading communication service companies, and (3) managers of telecommunication/MIS departments of major corporations. Future networking issues, such as developments in integrated-services digital network standards and technologies, are addressed.

  8. Development status of the Communications and Broadcasting Engineering Test Satellite (COMETS)

    Microsoft Academic Search

    Keisuke Ozawa; Kazuhiko Oshida; Junichi Aoyama; Naoki Sato; Masayoshi Kawaguchi; Katsumi Oishi; Mizuho Ikeda

    1993-01-01

    COMETS (Communications and Broadcasting Engineering Test Satellite) is the research and development purpose satellite in the area of satellite communications and broadcasting technologies, to be launched in 1997 by H-2 launch vehicle. The main mission is to experimentally demonstrate and evaluate the technologies on inter-orbit communications, advanced satellite broadcasting on Ka-band and advanced mobile satellite communications on Ka-band and millimeter-wave

  9. 47 CFR 73.295 - FM subsidiary communications services.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Section 73.295 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES FM Broadcast Stations § 73.295 FM subsidiary communications services. (a) Subsidiary...

  10. 47 CFR 73.295 - FM subsidiary communications services.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Section 73.295 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES FM Broadcast Stations § 73.295 FM subsidiary communications services. (a) Subsidiary...

  11. 47 CFR 73.295 - FM subsidiary communications services.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Section 73.295 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES FM Broadcast Stations § 73.295 FM subsidiary communications services. (a) Subsidiary...

  12. Hitchhiker payloads for new commercial satellite services

    NASA Astrophysics Data System (ADS)

    Elizondo, E. L.; Buntschuh, R. F.; Seliga, J. F.

    A hitchhiker package is an addition to a satellite which provides a payload capability not previously present on the satellite and which utilizes a relatively minor portion of the available satellite resources. In this paper, feasibility considerations for hitchhiker packages are discussed in a general way, and some practical hitchhiker packages are described. These are the Search and Rescue Satellite Aided Tracking System (SARSAT), the Geostar Radio Determination (RDSS) hitchhiker packages, the Aviation Satellite (Avsat) proposed early entry system, and the Mobile Satellite (MSS) proposed early entry system.

  13. Thin-route rural communications using Intelsat satellites

    NASA Astrophysics Data System (ADS)

    Jennings, R. D.; McManamon, P. M.

    Application requirements exist and are growing in developing countries for telecommunications services that can be supplied best by use of satellite technology. Many of these requirements can be satisfied with one or two telephone circuits per earth station location. In many areas of the world, the only satellite capacity available to support these thin-route service requirements is in the Intelsat system. Small earth stations, suited economically and sized to provide the required thin-route service capacity, have not been common in the Intelsat system. However, Intelsat is recognizing the need for thin-route services and the opportunities that will develop for providing these services using small earth stations in the Intelsat system. This paper explores the potential advantages of continuously-variable-slope delta modulation (CVSD) voice encoding and the technical parameters of small earth stations suited for thin-route services, as well as the developments within Intelsat for responding to these service needs.

  14. LMST-the lightweight multiband satellite communications terminal

    Microsoft Academic Search

    Alexander J. Kelly; Alan Henderson; J. Wandrei; J. Schwefler

    1994-01-01

    LMST is a rapidly deployable, self-contained satellite communications subsystem capable of accessing international, regional, military, and domestic satellites worldwide. Operation is supported at commercial C- and Ku-band frequencies, as is operation at military X-band frequencies. LMST is the first multiband terminal which is capable of rapid band change during deployment. All of the electronics are triband. Only the antenna feed

  15. An adaptive array antenna for mobile satellite communications

    NASA Technical Reports Server (NTRS)

    Milne, Robert

    1990-01-01

    The design of an adaptive array antenna for land vehicle operation and its performance in an operational satellite system is described. Linear and circularly polarized antenna designs are presented. The acquisition and tracking operation of a satellite is described and the effect on the communications signal is discussed. A number of system requirements are examined that have a major impact on the antenna design. The results of environmental, power handling, and RFI testing are presented and potential problems are identified.

  16. Partial Processing Satellite Relays for Frequency-Hop Antijam Communications

    Microsoft Academic Search

    S. Sussman; P. Kotiveeriah

    1982-01-01

    Military satellite communications systems may be implemented with varying levels of satellite on-board processing. For frequency-hop (FH) spread-spectrum signals two options are the dehop-rehop transponder (DRT) and the symbol regenerative processor (SRP). This paper considers FH,M-ary FSK modulation in the presence of full band and worst case partial-band noise jamming. The relationships among end-to-end signal-to-noise ratio (SNR) performance or probability

  17. Mobile small aperture satellite terminals for military communications

    Microsoft Academic Search

    Vijitha Weerackody; Lino Gonzalez

    2007-01-01

    The United States Army is currently developing a satellite-based network-centric waveform. Mobile terminals that are small and compact are highly desirable for the military. This article gives an overview of the technical challenges and performance issues when mobile small aperture satellite terminals are connected to a network- centric communication system. The specific issues addressed are regulatory limits on off-axis emissions,

  18. Extravehicular Crewman Work System (ECWS) study program. Volume 3: Satellite service

    NASA Technical Reports Server (NTRS)

    Wilde, R. C.

    1980-01-01

    The satellite service portion of the Extravehicular Crewman Work System Study defines requirements and service equipment concepts for performing satellite service from the space shuttle orbiter. Both normal and contingency orbital satellite service is required. Service oriented satellite design practices are required to provide on orbit satellite service capability for the wide variety of satellites at the subsystem level. Development of additional satellite service equipment is required. The existing space transportation system provides a limited capability for performing satellite service tasks in the shuttle payload bay area.

  19. Performance Limitations of a Free-Space Optical Communication Satellite Network Owing to Vibrations: Heterodyne Detection

    Microsoft Academic Search

    Shlomi Arnon; Stanley R. Rotman; Norman S. Kopeika

    1998-01-01

    Free-space optical communication between satellites in a distributed network can permit high data rates of communication between different places on Earth. To establish optical communication between any two satellites requires that the line of sight of their optics be aligned during the entire communication time. Because of the large distance between the satellites and the alignment accuracy required, the pointing

  20. The 30/20 GHz fixed communications systems service demand assessment. Volume 2: Main report

    NASA Technical Reports Server (NTRS)

    Gamble, R. B.; Seltzer, H. R.; Speter, K. M.; Westheimer, M.

    1979-01-01

    A forecast of demand for telecommunications services through the year 2000 is presented with particular reference to demand for satellite communications. Estimates of demand are provided for voice, video, and data services and for various subcategories of these services. The results are converted to a common digital measure in terms of terabits per year and aggregated to obtain total demand projections.

  1. Satellite Technologies and Services: Implications for International Distance Education.

    ERIC Educational Resources Information Center

    Stahmer, Anna

    1987-01-01

    This examination of international distance education and open university applications of communication satellites at the postsecondary level notes activities in less developed countries (LDCs); presents potential models for cooperation; and describes technical systems for distance education, emphasizing satellite technology and possible problems…

  2. Land Mobile Satellite Service (LMSS): A conceptual system design and identification of the critical technologies: Part 2: Technical report

    NASA Technical Reports Server (NTRS)

    Naderi, F. (editor)

    1982-01-01

    A conceptual system design for a satellite-aided land mobile service is described. A geostationary satellite which employs a large (55-m) UHF reflector to communicate with small inexpensive user antennas on mobile vehicles is discussed. It is shown that such a satellite system through multiple beam antennas and frequency reuse can provide thousands of radiotelephone and dispatch channels serving hundreds of thousands of users throughout the U.S.

  3. Development of Small Optical Antenna for Inter-Satellite Communication

    NASA Astrophysics Data System (ADS)

    Kodeki, Kazuhide; Kashiwase, Toshio; Suzuki, Ryutaro; Arimoto, Yoshinori

    In inter-satellite links with many Low Earth Orbit (LEO) satellites, each satellite will communicate with one or more satellites. In such cases, a satellite needs multiple, small, and light optical antennas. A communication link between satellites is not sustained at high latitudes because antenna drive angles are large due to high relative angular rates. To reduce such link lost time, a wide drive range with high speed is required for optical antennas. To meet these requirements, we propose a coude path type optical antenna. Furthermore, optical fiber application will be required to achieve optical communication of the next generation of gigabit class. Therefore, it is necessary to develop the technology which introduces the laser received with the optical antenna to an optical fiber. The optical antenna’s experimental model is equipped with optical fiber. This paper describes the mechanism, control system and experimental results of the optical antenna we have developed. The principle and performance of the coude path type optical antenna with optical fiber was verified by using an experimental model of the optical antenna.

  4. Fault-tolerant onboard digital information switching and routing for communications satellites

    NASA Technical Reports Server (NTRS)

    Shalkhauser, Mary JO; Quintana, Jorge A.; Soni, Nitin J.; Kim, Heechul

    1993-01-01

    The NASA Lewis Research Center is developing an information-switching processor for future meshed very-small-aperture terminal (VSAT) communications satellites. The information-switching processor will switch and route baseband user data onboard the VSAT satellite to connect thousands of Earth terminals. Fault tolerance is a critical issue in developing information-switching processor circuitry that will provide and maintain reliable communications services. In parallel with the conceptual development of the meshed VSAT satellite network architecture, NASA designed and built a simple test bed for developing and demonstrating baseband switch architectures and fault-tolerance techniques. The meshed VSAT architecture and the switching demonstration test bed are described, and the initial switching architecture and the fault-tolerance techniques that were developed and tested are discussed.

  5. Yamal satellite communication and broadcast system

    Microsoft Academic Search

    V. V. Remizov; B. V. Budzuliak; V. I. Rostenko; N. N. Sevastianov; N. I. Nagorny

    1998-01-01

    Management of such a large company as Gasprom is a complex task requiring permanent broadening of the sphere of application and updating of the information technologies. Having this in mind, since the 1990s Gasprom's top managers have been working towards modernization and updating of its technological communication network (TCN) on a modern technical basis. Gasprom communications network, one of the

  6. Interference susceptibility measurements for an MSK satellite communication link

    NASA Technical Reports Server (NTRS)

    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).

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

    NASA Technical Reports Server (NTRS)

    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.

  8. Time Division Access for Military Communications Satellites

    Microsoft Academic Search

    R. M. Huiltberg; F. H. Jean; M. E. Jones

    1965-01-01

    Simultaneous use of a single satellite repeater by several surface terminals is of considerable interest to the military user. A method of achieving multiple access by means of time division is described. Bursts of digital data from different surface terminals are interleaved in a manner that allows them to be identified and demodulated. A comparison is made between the access

  9. Effects of satellite transponder nonlinearities on spread spectrum satellite communication systems

    Microsoft Academic Search

    Masaaki Katayama; Norihiko Morinaga; Toshihiko Namekawa

    1982-01-01

    Correlation analysis using the autocorrelation function is applied to assess the effects of satellite-transponder nonlinearities on multiple access SS (spread-spectrum) signals when SS techniques are applied to satellite-communication systems. Both AM\\/PM-conversion and AM\\/AM-conversion nonlinearities are employed in the model (parameters k and L). The model can represent various kinds of nonlinearities by choosing the pair of parameters (k, L) and

  10. Communications satellite developments: Technology; Communications Satellite Systems Conference, 5th, Los Angeles, Calif., April 22-24, 1974, Technical Papers

    Microsoft Academic Search

    W. G. Schmidt; G. E. Lavean

    1976-01-01

    Aspects of spacecraft technology are considered, taking into account efficient high-capacity communications satellites, a constrained lens antenna for multiple-beam satellites, an ATS-6 interferometer, the development and the air bearing test of a double-gimballed momentum wheel attitude-control system, and the advantages of nuclear power systems compared to the current solar systems. Aspects of terminal technology are discussed along with subjects of

  11. Emerging communication technologies in emergency medical services

    Microsoft Academic Search

    Richard C. Hunt

    2002-01-01

    Advances in communication technologies are changing the face of emergency medical services (EMS). Two communication technologies in particular—cellular-enhanced 9-1-1 service and automatic crash notification (ACN)—will have a considerable impact on EMS. Although enhanced 9-1-1 service from land-line phones is now available in nearly every EMS system across the country, enhanced 9-1-1 service from cell phones currently does not exist. With

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

    NASA Technical Reports Server (NTRS)

    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.).

  13. A study and experiment plan for digital mobile communication via satellite

    NASA Technical Reports Server (NTRS)

    Jones, J. J.; Craighill, E. J.; Evans, R. G.; Vincze, A. D.; Tom, N. N.

    1978-01-01

    The viability of mobile communications is examined within the context of a frequency division multiple access, single channel per carrier satellite system emphasizing digital techniques to serve a large population of users. The intent is to provide the mobile users with a grade of service consistant with the requirements for remote, rural (perhaps emergency) voice communications, but which approaches toll quality speech. A traffic model is derived on which to base the determination of the required maximum number of satellite channels to provide the anticipated level of service. Various voice digitalization and digital modulation schemes are reviewed along with a general link analysis of the mobile system. Demand assignment multiple access considerations and analysis tradeoffs are presented. Finally, a completed configuration is described.

  14. Fiber optic links for millimeter wave communication satellites

    Microsoft Academic Search

    A. S. Daryoush; A. P. S. Khanna; K. Bhasin; R. Kunath

    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 fiber-optic network. Experimental results are reported that demonstrate optical control of active modules for satellite communication at 24 GHz. An approach called T\\/R level data mixing,

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

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

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

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

    NASA Technical Reports Server (NTRS)

    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.

  17. AIAA International Communication Satellite Systems Conference and Exhibit, 14th, Washington, DC, Mar. 22-26, 1992, Technical Papers. Pts. 1-3

    SciTech Connect

    Not Available

    1992-01-01

    The present conference on international communication satellite systems discusses GEO launch vehicle development, military Satcom systems, GEO mobile Satcom systems, advanced transponder technology, and digital network architecture. Attention is given to digital network architecture, the optical Satcom system, emerging launch alternatives, military and government Satcom systems, satellite communications developments in newly industrialized nations, launch options to nongeostationary orbits, and data relay satellite technology. Topics addressed include LEO satellite systems, earth terminal technology, personal communications, high data rate links via satellite, Italsat, antenna systems, Intelsat system and service development, new spacecraft system concepts, orbit/spectrum allocation and use, and ACTS technology. Also discussed are array antenna technology, VSAT and other small terminal systems, orbits, propagation, onboard satellite switching, reflector antenna technology, and panel small communication satellite systems.

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

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

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

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

    Microsoft Academic Search

    Shunkichi Isobe; Shingo Ohmori; Naokazu Hamamoto; Minoru Yamamoto

    1991-01-01

    Communications Research Laboratory (CRL) studied an advanced mobile satellite communications system using Ka and millimeter-wave bands in the R&D Satellite project. The project started in 1990 and the satellite will be launched in 1997. On-board multi-beam interconnecting is one of basic functions to realize one-hop connection among Very Small Aperture Terminals (VSATs), mobile, and hand-held terminals in future mobile satellite

  20. Optical deep space communication via relay satellite

    NASA Technical Reports Server (NTRS)

    Gagliardi, R. M.; Vilnrotter, V. A.; Dolinar, S. J., Jr.

    1981-01-01

    The possible use of an optical for high rate data transmission from a deep space vehicle to an Earth-orbiting relay satellite while RF links are envisioned for the relay to Earth link was studied. A preliminary link analysis is presented for initial sizing of optical components and power levels, in terms of achievable data rates and feasible range distances. Modulation formats are restricted to pulsed laser operation, involving bot coded and uncoded schemes. The advantage of an optical link over present RF deep space link capabilities is shown. The problems of acquisition, pointing and tracking with narrow optical beams are presented and discussed. Mathematical models of beam trackers are derived, aiding in the design of such systems for minimizing beam pointing errors. The expected orbital geometry between spacecraft and relay satellite, and its impact on beam pointing dynamics are discussed.

  1. The Army's Use of the Advanced Communications Technology Satellite

    NASA Technical Reports Server (NTRS)

    Ilse, Kenneth

    1996-01-01

    Tactical operations require military commanders to be mobile and have a high level of independence in their actions. Communications capabilities providing intelligence and command orders in these tactical situations have been limited to simple voice communications or low-rate narrow bandwidth communications because of the need for immediate reliable connectivity. The Advanced Communications Technology Satellite (ACTS) has brought an improved communications tool to the tactical commander giving the ability to gain access to a global communications system using high data rates and wide bandwidths. The Army has successfully tested this new capability of bandwidth-on-demand and high data rates for commanders in real-world conditions during Operation UPHOLD DEMOCRACY in Haiti during the fall and winter of 1994. This paper examines ACTS use by field commanders and details the success of the ACTS system in support of a wide variety of field condition command functions.

  2. Wearable Circularly Polarized Antenna for Personal Satellite Communication and Navigation

    Microsoft Academic Search

    Emmi K. Kaivanto; Markus Berg; Erkki Salonen; Peter de Maagt

    2011-01-01

    Integrating antennas into fabrics is a potential way for facilitating many applications, such as health monitoring of patients, fire-fighting, rescue work, and space and military per- sonal communications. This paper studies possibilities to construct a flexible, lightweight and mechanically robust textile antenna for dual-band satellite use: Iridium and GPS. Different textile mate- rials were characterized and the most promising materials

  3. Dual offset reflector multibeam antenna for international communications satellite applications

    Microsoft Academic Search

    R. Jorgensen; P. Balling; W. J. English

    1985-01-01

    Dual offset reflector antenna systems offer exciting possibilities for achieving both low scan losses and low cross polarization in geosynchronous communications satellite antennas providing narrow and multiple beam frequency reuse coverages over an 18 deg conical field of view. Novel geometrical configurations for the reflectors are characterized by simultaneously achieving: (1) blockage-free apertures for all element beams within the 18

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

    Microsoft Academic Search

    R. Strauss

    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

  5. Toward a Communications Satellite Network for Humanitarian Relief

    NASA Technical Reports Server (NTRS)

    Burleigh, Scott C.; Birrane, Edward J.

    2011-01-01

    Since the introduction in 2008 of the "Ring Road" concept, proposing a communications satellite network designed to support disadvantaged populations, there have been a number of advances in the underlying technologies, CubeSat picosatellites and Delay-Tolerant Networking. We review the original Ring Road proposal, discuss relevant recent technological progress, and offer some tentative notes on projected cost and performance.

  6. Multiquantum well beam-steering device for laser satellite communication

    Microsoft Academic Search

    Roee Lahat; Itamar Levy; Shlomi Arnon

    2002-01-01

    With the increasing interest in laser satellite communications, new methods are sought to solve the existing problems of accurate and rapid laser beam deflection. Current solutions in the form of galvanometers or piezo fast steering mirrors with one or two degrees of freedom are bulky, power-consuming and slow. The Multi-Quantum Well (MQW) is a semiconductor device with unique potential to

  7. Digital computer simulation of satellite quadrature data communication systems

    Microsoft Academic Search

    M. C. Jeruchim

    1975-01-01

    This paper describes a Monte-Carlo simulation developed to predict the bit error rate (BER) for digital satellite communication links using quadrature signaling (QPSK or QAM). Primary emphasis is placed on modeling considerations. The model contains two nonlinear amplifiers and thermal noise, phase noise, and bit timing jitter. Provision is made to either insert arbitrary transfer functions or to specify the

  8. Prediction of the effects of rain on satellite communication systems

    Microsoft Academic Search

    R. K. Crane

    1977-01-01

    The major propagation effects for satellite communication systems operating above 4 GHz are caused by rain. With the possible exceptions of depolarization and multiple scattering at frequencies above 20 GHz, these effects may be calculated if the distribution of rain intensity is known in both time and space. The major effects-attenuation and interference-require information about path and volume averaged rain

  9. CLOSED LOOP STABILITY CONTROLS FOR S-ALOHA SATELLITE COMMUNICATIONS

    E-print Network

    Kleinrock, Leonard

    Kleinrock Computer Science Department University of California, Los Angeles ABSTRACT S-ALOHA channels setting of the parameters). I. INTRODUCTION The S-ALOHA (slotted ALOHA) channel is a time divisionCLOSED LOOP STABILITY CONTROLS FOR S-ALOHA SATELLITE COMMUNICATIONS Mario Gerla and Leonard

  10. Satellite communication and broadcasting systems in the 21st century

    Microsoft Academic Search

    V. R. Anpilogov

    1998-01-01

    There has been much technical progress and development in all areas of technology over recent years. The information society, satellite communication and broadcasting are part of this process, and have become a characteristic of the second half of the 20th century. In the global information infrastructure (GII) today, the space segment, on the one hand, plays an integrating role, and

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

    NASA Technical Reports Server (NTRS)

    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.

  12. Precipitation scatter as an interference source in communication satellite systems

    Microsoft Academic Search

    Arnett S. Dennis

    1962-01-01

    Communication satellite systems operating at frequencies as high as 3 Gc are now in the active planning stage. A number of recent papers have dealt with the interference produced at the ground receiving sites of such systems by tropospheric scatter from sources below the radio horizon. However, theoretical and experimental data from the field of radar meteorology show that scattering

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

    NASA Technical Reports Server (NTRS)

    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.

  14. Applications of Multi Port Amplifier to personal satellite communications

    NASA Technical Reports Server (NTRS)

    Egami, Shunichiro

    1995-01-01

    In personal satellite communications, satellite antenna beam becomes narrow, and number of beams will be thirty to more than one hundred. This paper shows that Multi Port Amplifier is most suitable to multiple beam transmitter for personal communications satellite. It was shown that the single beam coverage area(cell) diameter is determined by personal earth station(PES) eirp, uplink C/No and uplink frequency band. Required number of cells for European or North American regional coverage at FPLMTS uplink frequency band is shown as around 32. It was shown that 32 beams systems will be easily implemented by using 2 set of 16-port MPA. Redundancy to SSPA failure is considered by increasing number of SSPAs. Actual configuration for 16-port MPA are briefly shown. The presented configuration will be easy to implement and the most economical solution.

  15. Application of adaptive antenna techniques to future commercial satellite communication

    NASA Technical Reports Server (NTRS)

    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.

  16. Development of antenna system for S-band mobile satellite communications and broadcasting

    Microsoft Academic Search

    Ken-ichi Haryu; Yasuhiko Yamasa; Teruki Okamoto; Yuichi Otsu; Kazuhiko Yoneyama

    1996-01-01

    Advanced Space Communications Research Laboratory is studying an antenna system for future S-band mobile satellite communication and broadcasting. This system uses a GEO satellite and is composed of a large deployable satellite antenna with a 10 m diameter mesh reflector and a mobile antenna for vehicles and hand-held terminals. In this paper, we present our deployable satellite antenna program and

  17. An active retrodirective array for satellite communications

    Microsoft Academic Search

    S. Andre; D. Leonard

    1964-01-01

    The concept and design of an active retrodirective array, resulting from the specialized requirements and constraints of space\\/earth communications, is presented. The advantages of employing active microwave gain are discussed. The attendant problem of instability is defined and several aspects of the solution, namely frequency offsetting and polarization isolation, are detailed. The latter technique makes use of orthogonally polarized \\

  18. Integrated text-communication services digital networks

    NASA Astrophysics Data System (ADS)

    Montemurro, R.; Villani, F.

    1980-12-01

    Circuit and packet switched facilities as well as distributed information processing units handling new text communication services are part of future integrated services digital networks. The functional integration of text communicaton procedures with the digital network is discussed. Unified handling of batch and interactive text communications is proposed. The use of standardized protocols at both transport and user service levels is suggested. The implementation of transport service layered functions into actual hierarchical communication levels is examined. It is shown possible to define standardized protocols common to both circuit switched and packet switched operating facilities. The text communication functions pertaining to session and presentation tasks are described. A session protocol common to both batch and interactive services is envisaged and real as well as virtual presentation services are considered.

  19. Frequency allocation problem in a SDMA satellite communication system Laurent Houssin12

    E-print Network

    Paris-Sud XI, Université de

    Frequency allocation problem in a SDMA satellite communication system Laurent Houssin12 , Christian to a clever algorithm in charge of resource allocation. As satellite communication systems move towards) in a satellite communication system involving a gateway connected to a terrestrial network and some user

  20. Neuronal somatic ATP release triggers neuron satellite glial cell communication in dorsal

    E-print Network

    Newman, Eric A.

    Neuronal somatic ATP release triggers neuron­ satellite glial cell communication in dorsal root activates P2X7 receptors in satellite cells that enwrap each DRG neuron and triggers the communication neuronal somata and thus triggers bidirectional communication between neurons and satellite cells. Results

  1. Design of Rate Constrained Multi-user Receivers for Satellite Communications

    E-print Network

    Paris-Sud XI, Université de

    Design of Rate Constrained Multi-user Receivers for Satellite Communications Sami Mekki Ecole: merouane.debbah@supelec.fr Abstract--In the realm of satellite communications, one of the great impairments allocation for successive interference cancellation can enhance the performance of satellite communications

  2. 22nd AIAA International Communications Satellite Systems Conference & Exhibit 2004 9 -12 May 2004, Monterey, California

    E-print Network

    Baras, John S.

    22nd AIAA International Communications Satellite Systems Conference & Exhibit 2004 9 -12 May 2004 of satellite technology for aeronautical communications, the airline industry is developing a design for a global satellite-based communications system to meet the needs of the aviation industry [2]. Copyright

  3. The Transformational Satellite Communications System (TSAT) is poised to become the DoD's next generation

    E-print Network

    Touch, Joe

    1 of 7 ABSTRACT The Transformational Satellite Communications System (TSAT) is poised to become, as well as providing security at physical and link layer. I. INTRODUCTION Satellite communications, the US Government has a history of deploying pro- tected satellite communications systems, beginning

  4. Optimizing Satellite Communications With Adaptive and Phased Array Antennas Mary Ann Ingram

    E-print Network

    Ingram, Mary Ann

    Optimizing Satellite Communications With Adaptive and Phased Array Antennas Mary Ann Ingram the focus of the current project is for a ground station to communicate with only one satellite at a time communication with mul- tiple satellites. Two phased array technologies are being investigated by re- searchers

  5. Space Communications 21 (2007/2008) 6982 69 Satellite system performance assessment for

    E-print Network

    Mailhes, Corinne

    Space Communications 21 (2007/2008) 69­82 69 IOS Press Satellite system performance assessment. Concurrent satellite systems have been proposed for IFE (In-Flight Entertainment) communications, thus. At the same time, an increasing interest in the use of satellite communications for ATC (Air Traffic Control

  6. Assessing the Technical, Economic and Policy-centered Feasibility of a Proposed Satellite Communication System for

    E-print Network

    in Technology and Policy Abstract Satellite communication systems remain one of the most under utilized and policy related frontiers of the problem are integrated within a MATLAB based satellite communication to establish a low earth orbit satellite communications system for the developing world. The inputs

  7. Perceived issues associated with military use of satellite based personal communications systems

    Microsoft Academic Search

    A. Bartko; A. Q. Le; T. N. Thomas

    1995-01-01

    As charged by Congress and the Office of the Secretary of Defense, the Defense Information Systems Agency (DISA) created the Commercial Satellite Communications Initiatives (CSCI) program. The CSCI program's purpose is to assess the use of available and planned commercial communications satellites to fulfill, in a cost-effective manner, certain military communications that would be otherwise provided by Government satellite systems.

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

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

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

  9. A TMS320-based modem for the aeronautical-satellite core data service

    NASA Astrophysics Data System (ADS)

    Moher, Michael L.; Lodge, John H.

    The International Civil Aviation Organization (ICAO) Future Air Navigation Systems (FANS) committee, the Airlines Electronics Engineering Committee (AEEC), and Inmarsat have been developing standards for an aeronautical satellite communications service. These standards encompass a satellite communications system architecture to provide comprehensive aeronautical communications services. Incorporated into the architecture is a core service capability, providing only low rate data communications, which all service providers and all aircraft earth terminals are required to support. In this paper an implementation of the physical layer of this standard for the low data rate core service is described. This is a completely digital modem (up to a low intermediate frequency). The implementation uses a single TMS320C25 chip for the transmit baseband functions of scrambling, encoding, interleaving, block formatting and modulation. The receiver baseband unit uses a dual processor configuration to implement the functions of demodulation, synchronization, de-interleaving, decoding and de-scrambling. The hardware requirements, the software structure and the algorithms of this implementation are described.

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

    ERIC Educational Resources Information Center

    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…

  11. Compatibility - A challenge to universal communications Global cables and satellite communication

    Microsoft Academic Search

    T. B. Westfall

    1966-01-01

    The prognosis for worldwide communications is discussed from six viewpoints. A look at the future roles of satellites and submarine cables, an evaluation of the advances in international telephone routing, and a CCITT progress report are presented. The technical and economic tasks necessary to achieve compatibility are outlined, and Comsat's organizational structure, and its relationship to international communications, is appraised.

  12. FET Mixers for Communication Satellite Transponders

    Microsoft Academic Search

    P. Bura; R. Dikshit

    1976-01-01

    Two different types of FET mixer circuits have been developed for 6\\/4 GHz frequency translation for communications sateIIite transponder. Gate mixer uses non-linear I d - V g characteristic, with LO being injected into the gate circuit, while in the drain mixer the LO is injected into the drain circuit and non-linear I d - V d characteristic is utilized.

  13. Performance studies of Low Earth Orbit Satellite (LEOS) communication networks for global communications

    SciTech Connect

    Raines, R.A.; Janoso, R.F.; Stenger, D.K. [Department of Electrical and Computer Engineering Air Force Institute of Technology Wright-Patterson AFB, Ohio45433-7765 (United States)

    1997-01-01

    Communicating appropriate information to desired destinations is of critical importance to the Air Force and the Department of Defense (DoD). The communications infrastructure used to provide this information must be reliable and also efficient in terms of minimizing delay. Additionally, {open_quotes}anytime and anywhere{close_quotes} communication capabilities are desired of the infrastructure. In order to provide global communications, satellite communication systems must be used for primary as well as supplemental communication mediums. Satellite communication systems can be used to provide the infrastructure with the {open_quotes}anytime and anywhere{close_quotes} capability. Recent advances in microelectronic and cellular radio technologies have allowed for the proposed implementation of low earth orbit satellite (LEOS) communication networks for global personal communications. This paper examines the performance of LEOS networks in a packet-switched environment. Performance is defined here in terms of link availability and reliability in a faulty environment. An overview of LEOS systems is provided, as well as critical issues associated with the implementation of such a system. To illustrate the nature of LEOS network communications, the commercially proposed system Iridium is examined. {copyright} {ital 1997 American Institute of Physics.}

  14. Vibration-induced jitter control in satellite optical communication

    NASA Astrophysics Data System (ADS)

    Xue, Zheng-yan; Qi, Bo; Ren, Ge

    2013-08-01

    Laser satellite communication has become especially attractive in recent years. However, because the laser beam is very narrow and there is a long distance between satellites, the laser communication channel is very sensitive to vibrations of the optical platform. These vibrations cause optical jitter, leading to the reduction of received signals and bit-error rate degradation. Consequently, optical jitter control with PAT (pointing acquisition and tracking) subsystems is a critical problem in laser satellite communication. To compensate for the platform vibration effectively in realtime, in this paper, an adaptive feedback control technique based on Youla-parameterization is presented, which can adapt to the current disturbance acting on the laser beam by adjusting its parameters in realtime to maintain optimal performance. The main idea is to use the well-known Youla parameterization formula to construct a feedback control scheme with the guaranteed closed loop stability, and the feedback controller is a function of plant coprime factors and a free parameter Q. For adaptive disturbance estimation, the free parameter Q is set to an adaptive finite impulse response (FIR) filter, the coefficients of which are updated by a recursive least-squares (RLS) algorithm in realtime. It is shown in experiment that the adaptive feedback control technique based on Youla-parameterization can reject the optical jitter caused by satellite platform vibration effectively and improve the performance of the system.

  15. Emergency Communications over Satellite: the WISECOM Approach

    Microsoft Academic Search

    M. Berioli; N. Courville; M. Werner

    2007-01-01

    This paper presents the overall architecture of the WISECOM system, which can quickly re-establish and provide telecommunication services after a disaster. The architecture is explained and it is described together with a role model, which adapts to the system. The work tries to map the existing complex interactions taking place nowadays in an emergency situation to a sensible architecture, which

  16. Destination-directed, packet-switched architecture for a geostationary communications satellite network

    NASA Technical Reports Server (NTRS)

    Ivancic, William D.; Shalkhauser, Mary JO; Bobinsky, Eric A.; Soni, Nitin J.; Quintana, Jorge A.; Kim, Heechul; Wager, Paul; Vanderaar, Mark

    1993-01-01

    A major goal of the Digital Systems Technology Branch at the NASA Lewis Research Center is to identify and develop critical digital components and technologies that either enable new commercial missions or significantly enhance the performance, cost efficiency, and/or reliability of existing and planned space communications systems. NASA envisions a need for low-data-rate, interactive, direct-to-the-user communications services for data, voice, facsimile, and video conferencing. The network would provide enhanced very-small-aperture terminal (VSAT) communications services and be capable of handling data rates of 64 kbps through 2.048 Mbps in 64-kbps increments. Efforts have concentrated heavily on the space segment; however, the ground segment has been considered concurrently to ensure cost efficiency and realistic operational constraints. The focus of current space segment developments is a flexible, high-throughput, fault-tolerant onboard information-switching processor (ISP) for a geostationary satellite communications network. The Digital Systems Technology Branch is investigating both circuit and packet architectures for the ISP. Destination-directed, packet-switched architectures for geostationary communications satellites are addressed.

  17. 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

    NASA Technical Reports Server (NTRS)

    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.

  18. Intelligent fault isolation and diagnosis for communication satellite systems

    NASA Technical Reports Server (NTRS)

    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.

  19. The link evaluation terminal for the advanced communications technology satellite experiments program

    NASA Technical Reports Server (NTRS)

    May, Brian D.

    1992-01-01

    The experimental NASA satellite, Advanced Communications Technology Satellite (ACTS), introduces new technology for high throughput 30 to 20 GHz satellite services. Contained in a single communication payload is both a regenerative TDMA system and multiple 800 MHz 'bent pipe' channels routed to spot beams by a switch matrix. While only one mode of operation is typical during any experiment, both modes can operate simultaneously with reduced capability due to sharing of the transponder. NASA-Lewis instituted a ground terminal development program in anticipation of the satellite launch to verify the performance of the switch matrix mode of operations. Specific functions are built into the ground terminal to evaluate rain fade compensation with uplink power control and to monitor satellite transponder performance with bit error rate measurements. These functions were the genesis of the ground terminal's name, Link Evaluation Terminal, often referred to as LET. Connectors are included in LET that allow independent experimenters to run unique modulation or network experiments through ACTS using only the RF transmit and receive portions of LET. Test data indicate that LET will be able to verify important parts of ACTS technology and provide independent experimenters with a useful ground terminal. Lab measurements of major subsystems integrated into LET are presented. Bit error rate is measured with LET in an internal loopback mode.

  20. The Link Evaluation Terminal for the Advanced Communications Technology Satellite Experiments Program

    NASA Technical Reports Server (NTRS)

    May, Brian D.

    1992-01-01

    The experimental NASA satellite, Advanced Communications Technology Satellite (ACTS), introduces new technology for high throughput 30 to 20 GHz satellite services. Contained in a single communication payload is both a regenerative TDMA system and multiple 800 MHz 'bent pipe' channels routed to spot beams by a switch matrix. While only one mode of operation is typical during any experiment, both modes can operate simultaneously with reduced capability due to sharing of the transponder. NASA-Lewis instituted a ground terminal development program in anticipation of the satellite launch to verify the performance of the switch matrix mode of operations. Specific functions are built into the ground terminal to evaluate rain fade compensation with uplink power control and to monitor satellite transponder performance with bit error rate measurements. These functions were the genesis of the ground terminal's name, Link Evaluation Terminal, often referred to as LET. Connectors are included in LET that allow independent experimenters to run unique modulation or network experiments through ACTS using only the RF transmit and receive portions of LET. Test data indicate that LET will be able to verify important parts of ACTS technology and provide independent experimenters with a useful ground terminal. Lab measurements of major subsystems integrated into LET are presented. Bit error rate is measured with LET in an internal loopback mode.

  1. Compact mobile terminals for multi-beam mobile satellite communication systems

    NASA Astrophysics Data System (ADS)

    Sakai, Tsutomu; Komagata, Hitoshi; Terada, Noriyoshi; Hagiwara, Eiji

    Two types of compact mobile terminals for multibeam mobile satellite communications systems are described. One of them is designed for telephone service with 8-kb/s or 16-kb/s APC-AB (adaptive predictive coding-asynchronous binary) codecs or corresponding nontelephone services, such as facsimile; the other is for low-speed message service. For the 8-kb/s or 16-kb/s mobile terminal, an electronically steerable switched antenna technique, a digital signal processing technique, and custom LSIs are adopted to reduce equipment size. This terminal can be mounted on a small vessel or vehicle. For the message terminal, an omnidirectional antenna with a conically shaped radiation pattern is used, and its portability allows easy and instant communications anywhere at any time.

  2. An optimized bandwidth efficient demand assigned protocol for integrated Mobile Satellite Services

    NASA Technical Reports Server (NTRS)

    Yan, T.-Y.; Wang, C. C.

    1985-01-01

    This paper describes the design of a demand assigned protocol based on bandwidth efficiency for integrated services of a Mobile Satellite System (MSS). An MSS provides data (closed-ended) and voice (open-ended) communications services for a large number of mobile users dispersed over a wide geographical area. Each mobile requests its desired service through a designated set of channels to a network management center. Either pure or slotted ALOHA random access scheme can be used to make connection requests, while data and voice communications are demand assigned. All channels have equal bandwidth and can be adaptively used for reservation requests, data connections or voice connections to maximize the bandwidth utilization. In this paper, perfect communications channels are assumed. It has been shown that, for the case considered, using the slotted ALOHA scheme for making connection requests can save about 30 percent on the total number of channels over using the pure ALHOA scheme.

  3. Satellite Servicing in Mission Design Studies at the NASA GSFC

    NASA Technical Reports Server (NTRS)

    Leete, Stephen J.

    2003-01-01

    Several NASA missions in various stages of development have undergone one-week studies in the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) Integrated Mission Design Center (IMDC), mostly in preparation for proposals. The possible role of satellite servicing has been investigated for several of these missions, applying the lessons learned from Hubble Space Telescope (HST) servicing, taking into account the current state of the art, projecting into the future, and implementing NASA long-range plans, and is presented here. The general benefits and costs of injecting satellite servicing are detailed, including components such as mission timeline, mass, fuel, spacecraft design, risk abatement, life extension, and improved performance. The approach taken in addressing satellite servicing during IMDC studies is presented.

  4. Space Network IP Services (SNIS): An Architecture for Supporting Low Earth Orbiting IP Satellite Missions

    NASA Technical Reports Server (NTRS)

    Israel, David J.

    2005-01-01

    The NASA Space Network (SN) supports a variety of missions using the Tracking and Data Relay Satellite System (TDRSS), which includes ground stations in White Sands, New Mexico and Guam. A Space Network IP Services (SNIS) architecture is being developed to support future users with requirements for end-to-end Internet Protocol (IP) communications. This architecture will support all IP protocols, including Mobile IP, over TDRSS Single Access, Multiple Access, and Demand Access Radio Frequency (RF) links. This paper will describe this architecture and how it can enable Low Earth Orbiting IP satellite missions.

  5. The 30/20 Gigahertz transponder study. [wideband multichannel transponders for a communications satellite

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Design features and performance parameters are described for three types of wideband multiple channel satellite transponders for use in a 30/20 GHz communications satellite, which provides high data rate trunking service to ten ground station terminals. The three types of transponder are frequency division multiplex (FDM), time division multiplex (TDM), and a hybrid transponder using a combination of FDM and TDM techniques. The wideband multiple beam trunking concept, the traffic distribution between the trunking terminals, and system design constraints are discussed. The receiver front end design, the frequency conversion scheme, and the local oscillator design are described including the thermal interface between the transponders and the satellite. The three designs are compared with regard to performance, weight, power, cost and initial technology. Simplified block diagrams of the baseline transponder designs are included.

  6. ISO/OSI satellite communication network

    NASA Astrophysics Data System (ADS)

    Birch, David G. W.

    A strategy for the specification and implementation of a Very Small Aperture Terminal (VSAT) Managed Network Service is presented, based on the International Standards Organization (ISO) specification processes, ISO 7498. The management strategy for the system configuration, security, faults, accounting, performance, and user interface are described. The implementation strategy advocates the maximum use of off-the-shelf components and the development of standard gateways and packet assembler/dissassembler architectures. It is found that the VSAT network can support functions such as point-to-multipoint transmission and group addressing at the network layer.

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

    NASA Technical Reports Server (NTRS)

    Young, S. Lee

    1987-01-01

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

  8. WORLD DATA SERVICES Iridium Satellite LLC Rev. 2; June 15, 2001

    E-print Network

    Ashley, Michael C. B.

    WORLD DATA SERVICES Overview Iridium Satellite LLC Rev. 2; June 15, 2001 #12;IRIDIUM WORLD DATA Introduction to Iridium World Data Services............................................................................................ 6 Iridium Satellite LLC 2 Rev. 2; June 15, 2001 #12;IRIDIUM WORLD DATA SERVICES

  9. Low earth orbit satellite/terrestrial mobile service compatibility

    NASA Astrophysics Data System (ADS)

    Sheriff, R. E.; Gardiner, J. G.

    Digital cellular mobile 'second generation' systems are now gradually being introduced into service; one such example is GSM, which will provide a digital voice and data service throughout Europe. Total coverage is not expected to be achieved until the mid '90's, which has resulted in several proposals for the integration of GSM with a geostationary satellite service. Unfortunately, because terrestrial and space systems have been designed to optimize their performance for their particular environment, integration between a satellite and terrestrial system is unlikely to develop further than the satellite providing a back-up service. This lack of system compatibility is now being addressed by system designers of third generation systems. The next generation of mobile systems, referred to as FPLMTS (future public land mobile telecommunication systems) by CCIR and UMTS (universal mobile telecommunication system) in European research programs, are intended to provide inexpensive, hand-held terminals that can operate in either satellite, cellular, or cordless environments. This poses several challenges for system designers, not least in terms of the choice of multiple access technique and power requirements. Satellite mobile services have been dominated by the geostationary orbital type. Recently, however, a number of low earth orbit configurations have been proposed, for example Iridium. These systems are likely to be fully operational by the turn of the century, in time for the implementation of FPLMTS. The developments in LEO mobile satellite service technology were recognized at WARC-92 with the allocation of specific frequency bands for 'big' LEO's, as well as a frequency allocation for FPLMTS which included a specific satellite allocation. When considering integrating a space service into the terrestrial network, LEO's certainly appear to have their attractions: they can provide global coverage, the round trip delay is of the order of tens of milliseconds, and good visibility to the satellite is usually possible. This has resulted in their detailed investigation in the European COST 227 program and in the work program of the European Telecommunications Standards Institute (ETSI). This paper will consider the system implications of integrating a LEO mobile service with a terrestrial service. Results will be presented from simulation software to show how a particular orbital configuration affects the performance of the system in terms of area coverage and visibility to a terminal for various locations and minimum elevation angle. Possible network topologies are then proposed for an integrated satellite/terrestrial network.

  10. Channel Estimation And Multiuser Detection In Asynchronous Satellite Communications

    E-print Network

    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.

  11. Secure Satellite Communication Systems Design with Individual Secrecy Rate Constraints

    E-print Network

    Lei, Jiang; Vázquez-Castro, M A; Hjørungnes, Are

    2011-01-01

    In this paper, we study multibeam satellite secure communication through physical (PHY) layer security techniques, i.e., joint power control and beamforming. By first assuming that the Channel State Information (CSI) is available and the beamforming weights are fixed, a novel secure satellite system design is investigated to minimize the transmit power with individual secrecy rate constraints. An iterative algorithm is proposed to obtain an optimized power allocation strategy. Moreover, sub-optimal beamforming weights are obtained by completely eliminating the co-channel interference and nulling the eavesdroppers' signal simultaneously. In order to obtain jointly optimized power allocation and beamforming strategy in some practical cases, e.g., with certain estimation errors of the CSI, we further evaluate the impact of the eavesdropper's CSI on the secure multibeam satellite system design. The convergence of the iterative algorithm is proven under justifiable assumptions. The performance is evaluated by taki...

  12. Considerations for NATO satellite communications in the post-2000 era

    NASA Astrophysics Data System (ADS)

    Ince, A. Nejat

    1993-02-01

    The National Delegates Board of AGARD, upon recommendation by the Avionics Panel of AGARD, approved in March 1986 the establishment of WG-13 to study satellite communications for NATO under the direction of Prof. Dr. Nejat Ince of Turkey. Some 14 scientists/engineers, from research and industrial establishments of Canada, France, the Federal Republic of Germany, Norway, Turkey, the United Kingdom, the United States of America as well as from International Military Staff of NATO and SHAPE Technical Centre, participated in the work of WG-13. This paper is a brief summary of the studies carried out by the group in the period 1988-1990 on the type of satellite communication systems which NATO can have in the post-2000 era including the critical techniques and technologies that need to be developed for this purpose.

  13. Coherent versus noncoherent signaling for satellite-aided mobile communications

    NASA Technical Reports Server (NTRS)

    Davarian, F.; Sumida, J.

    1986-01-01

    The use of coherent versus noncoherent communications is an unresolved issue for the mobile satellite community. Should one select the more robust but less efficient noncoherent strategy for communications over satellite-aided mobile channels, or does the introduction of a space platform in the mobile link improve signal stability (both amplitude and phase) such that conventional coherent schemes become attractive? This publication tries to answer some of the questions by discussing the results from experiments using a coherent QPSK receiver. The issues discussed include items such as the measured performance in Rician fading, the link error floor in a fading environment, etc. The results are compared and contrasted with that of a noncoherent limiter/discriminator FM receiver.

  14. Multipath link and modem design for satellite mobile communications

    NASA Astrophysics Data System (ADS)

    Gardner, F. M.

    1983-08-01

    Modems for digital L-band communication between satellites and aircraft, ships, and land vehicles are discussed. Low-rate, low-cost communications for small users is desired, so antennas are nonsteerable. Received signal-to-noise ratios are small so power conservation is critically important. Reflections from the Earth's surface have significant amplitude and cause multipath interference to the desired signal. Data rates of 100, 1200, and 4800 bps were considered. Modulation types examined include BPSK/DPSK, FSK, and GMSK. Digital implementation of the modems is proposed wherever feasible.

  15. Satellite hemodialysis services for patients with end stage renal disease.

    PubMed

    Organ, Kathy; MacDonald, Sandra

    2014-01-01

    More than 40,000 Canadians are living with end stage renal disease and approximately 22,400 of those are currently being treated with hemodialysis (The Kidney Foundation of Canada, 2013). Long distance travel to access hemodialysis services can be a serious burden for patients, and travelling more than 60 minutes can mean a 20% greater risk for death, as compared with those who travel 15 minutes or less (Moist et al., 2008). Satellite hemodialysis units are seen as one solution to this problem. This study assessed the impact of services provided by one satellite hemodialysis unit on patients' satisfaction, access to care and quality of life using a qualitative interview research design. Seven patients were interviewed and three themes emerged including the burden of long distance travel before satellite services (safety, time and cost), satisfaction with satellite services (pleasant environment and continuity of care), and improved quality of life. This study showed that a satellite hemodialysis unit improved access to services and enhanced the quality of life of those patients who participated in the study. PMID:24783770

  16. IEEE Wireless Communications October 200554 1536-1284/05/$20.00 2005 IEEE PRESENT AND FUTURE SATELLITE COMMUNICATIONS

    E-print Network

    Atiquzzaman, Mohammed

    PRESENT AND FUTURE SATELLITE COMMUNICATIONS SHAOJIAN FU, OPNET MOHAMMED ATIQUZZAMAN, UNIVERSITY of GEO satellites makes them less desirable for real-time applica- tions, such as voice communicationsIEEE Wireless Communications · October 200554 1536-1284/05/$20.00 © 2005 IEEE Gateway 1 LEO1 GEO1

  17. Satellite Communications and Educational Television in Less Developed Countries. President's Task Force on Communications Policy. Staff Paper Three.

    ERIC Educational Resources Information Center

    Rostow, Eugene V.

    A staff paper submitted to the President's Task Force on Communications Policy discusses the implications of satellites on communications development in less developed countries. A global satellite system promises fast, direct, international communications to nations whose present surface facilities are inadequate--at a considerable savings over…

  18. Wide band hat-fed reflector antenna for satellite communications

    Microsoft Academic Search

    E. G. Geterud; J. Yang; T. Ostling

    2011-01-01

    This paper presents a new design of a hat-fed reflector antenna for satellite communication, where low sidelobe and cross polar levels are required over a wideband. The hat feed has been optimized in the design by using the genetic algorithm (GA) through a commercial FDTD solver QuickWave V2D together with own developed Matlab code. The Gaussian vertex plate has been

  19. Quantitative Assessment of Technology Infusion in Communications Satellite Constellations

    Microsoft Academic Search

    Olivier L. De Weck; Darren D. Chang; Ryutaro Suzuki; Eihisa Morikawa; Da Antenna Diameter

    2003-01-01

    A methodology for quantitative assessment of new technologies is presented in the context of communications satellite constellations. The fundamental idea is that new technologies will shift the Pareto-optimal frontier when considering tradeos between performance, lifecycle cost and capacity. The suggested process first establishes a baseline by finding a Pareto optimal set of architectures on the basis of mature, state-of-the- art

  20. Multi-gigabit laser communications for satellite cross-links

    Microsoft Academic Search

    J. A. Maynard; M. Ross; J. D. Wolf

    1979-01-01

    Nd:YAG space laser communications systems are being developed with multi-gigabit capability. A 1 Gbps system Engineering Feasibility Model which has been tested successfully both functionally and environmentally, has led to further designs for space qualified multi-gigabit packages. A system configuration for a 2 Gbps duplex cross-link between synchronous satellites is described. The 2 Gbps transceiver characteristics are addressed in detail

  1. Satellite Communication Performance Evaluation Model for Aircraft Systems

    Microsoft Academic Search

    Keith A. Sadler

    1983-01-01

    The model was developed to cost-effectively evaluate candidate antenna systems for Satellite Communications between the P-3C Orion Anti-Submarine aircraft and the Navy Anti-Submarine Warfare Operational Centers (ASWOC). Constituent elements of the model are discussed, data used by the model are described and a comparison to actual flight test results is made. Limitations in the model are indicated with possible improvements

  2. An analysis of bidirectional use of frequencies for satellite communications

    NASA Technical Reports Server (NTRS)

    Whyte, W. A., Jr.; Miller, E. F.; Sullivan, T.; Miller, J. E.

    1986-01-01

    The bi-directional use of frequencies allocated for space communications has the potential to double the orbit/spectrum capacity available. The technical feasibility of reverse band use (RBU) at C-band (4 GHz uplinks and 6 GHz downlinks) is studied. The analysis identifies the constraints under which both forward and reverse band use satellite systems can share the same frequencies with terrestrial, line of sight transmission systems. The results of the analysis show that RBU satellite systems can be similarly sized to forward band use (FBU) satellite systems. In addition, the orbital separation requirements between RBU and FBU satellite systems are examined. The analysis shows that a carrier to interference ratio of 45 dB can be maintained between RBU and FBU satellites separated by less than 0.5 deg., and that a carrier to interference ratio of 42 dB can be maintained in the antipodal case. Rain scatter propagation analysis shows that RBU and FBU earth stations require separation distances of less than 10 km at a rain rate of 13.5 mm/hr escalating to less than 100 km at a rain rate of 178 mm/hr for earth station antennas in the 3 to 10 m range.

  3. AIAA International Communication Satellite Systems Conference, 12th, Arlington, VA, Mar. 13-17, 1988, Technical Papers

    SciTech Connect

    Not Available

    1988-01-01

    Various papers concerning communication satellite systems are presented. The general topics addressed include: regional and international systems, orbit and spectrum use, spacecraft bus developments, domestic satellite systems, advanced systems concepts, earth stations, report on NASA Advanced Communications Technology Satellite, direct broadcast satellite systems, and advanced communications payloads. Also considered are: small terminals, military satellite systems, on-board processing technology, power amplifiers, economic aspects of communication satellite systems, mobile satellite systems, launch vehicle report, transponder technology, multipurpose satellite systems, systems architecture, satellite antenna technology, and satellite operations.

  4. Mobile satellite services for public safety, disaster mitigation and disaster medicine

    NASA Technical Reports Server (NTRS)

    Freibaum, Jerry

    1990-01-01

    Between 1967 and 1987 nearly three million lives were lost and property damage of $25 to $100 billion resulted form natural disasters that adversely affected more than 829 million people. The social and economic impacts have been staggering and are expected to grow more serious as a result of changing demographic factors. The role that the Mobile Satellite Service can play in the International Decade is discussed. MSS was not available for disaster relief operations during the recent Loma Prieta/San Francisco earthquake. However, the results of a review of the performance of seven other communication services with respect to public sector operations during and shortly after the earthquake are described. The services surveyed were: public and private telephone, mobile radio telephone, noncellular mobile radio, broadcast media, CB radio, ham radio, and government and nongovernment satellite systems. The application of MSS to disaster medicine, particularly with respect to the Armenian earthquake is also discussed.

  5. The outline of the Communications and Broadcasting Engineering Test Satellite (COMETS)

    Microsoft Academic Search

    Yuichi Fujiwara; Hisashi Morikawa; Toshikazu Kotoh; Akira Awasawa; Chiharu Ohuchi; Masaaki Shimada

    1992-01-01

    The National Space Development Agency of Japan (NASDA) plans to launch the Communications and Broadcasting Engineering Test Satellite (COMETS) by H-II launch vehicle in February, 1997. The research and development for Japan's next Communications Satellite-4 (CS-4) and Experimental Data Relay and Tracking Satellite (EDRTS) were changed into the new project of COMETS in June, 1990. The basic design was started

  6. The outline of the Communications and Broadcasting Engineering Test Satellite (COMETS)

    Microsoft Academic Search

    Hisashi Morikawa; Toshikazu Koto; Akira Awasawa; Chiharu Ohuchi; Yuichi Fujiwara

    1991-01-01

    The National Space Development Agency of Japan (NASDA) plans to launch the Communications and Broadcasting Engineering Test Satellite (COMETS) by the H 2 rocket at the beginning of 1997. The research and development for Communications Satellite 4 (CS 4) and Experimental Data Relay and Tracking Satellite (EDRTS) were changed into the new project of COMETS in June 1990. COMETS is

  7. An advanced satellite communication system for ISDN subscriber and trunk applications - DYANET-II

    Microsoft Academic Search

    Toru Otsu; Masahiro Umehira; Masafumi Onuki; Hiroshi Nakashima

    1992-01-01

    This paper describes an advanced satellite communication system for ISDN subscriber and trunk applications that is integrated into a terrestrial ISDN. The system concept of DYANET (DYnamic channel Assigning and routing satellite aided digital NETwork) has been extended to a new platform called DYANET-II which allows satellite communications to be applied to ISDN subscriber lines as well as trunk circuits.

  8. Satellite Communications for Aeronautics Applications: Technology Development and Demonstration

    NASA Technical Reports Server (NTRS)

    Kerczewski, Robert J.; Hoder, Douglas J.; Zakrajsek, Robert J.

    2001-01-01

    The National Aeronautics and Space Administration (NASA) is performing research and development to improve the safety and increase the capacity of the National Airspace System (NAS). Improved communications, especially to and from the aircraft flight deck, has been identified as an essential enabling technology for future improvements to the air traffic management system and aviation safety. NASA's Glenn Research Center is engaged in research and development of satellite communications technologies for aeronautical applications. A mobile aero terminal has been developed for use with Ku band commercial communications satellites. This experimental terminal will be used in mobile ground and air-based tests and demonstrations during 2000-2004. This paper will describe the basic operational parameters of the Ku Band aero terminal, the communications architecture it is intended to demonstrate, and the key technology issues being addressed in the tests and demonstrations. The design of the Ku Band aero terminal and associated ground testbed, planned tests and demonstrations, and results to date will be presented.

  9. 47 CFR 73.593 - Subsidiary communications services.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 false Subsidiary communications services. 73.593 ...Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED... § 73.593 Subsidiary communications services. The licensee...inconsistent with its public broadcasting responsibilities....

  10. 47 CFR 73.593 - Subsidiary communications services.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 false Subsidiary communications services. 73.593 ...Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED... § 73.593 Subsidiary communications services. The licensee...inconsistent with its public broadcasting responsibilities....

  11. Some Features of Maritime Telex Service Communication.

    ERIC Educational Resources Information Center

    Johnson, Barry

    1995-01-01

    This article analyzes four categories of English-language maritime telex service communication: (1) standard, system- generated messages; (2) standard procedures for transmitting messages; (3) nonstandard messages related to maritime mobile radio service (MMRS); and (4) nonstandard messages related to the organization, procedures, or equipment of…

  12. An adaptive digital beamforming network for satellite communication systems

    NASA Astrophysics Data System (ADS)

    Barrett, M.; Fernandez, J.; Lagunas, M. A.; Coromina, F.

    1991-10-01

    The use of adaptive digital beamforming techniques has, until recently, been largely restricted to high performance military radar systems. Recent advances in digital technology, however, have enabled the design of single chip digital beamforming networks. This, coupled with advances in digital signal processor technology, enables complete beamforming systems to be constructed at a lower cost, thus making the application of these techniques to commercial communications systems attractive. The design and development of such an adaptative digital beamforming network are described. The system is being developed as a proof of concept laboratory based demonstrator to enable the feasibility of adaptive digital beamforming techniques for communication systems to be determined. Ultimately, digital beamforming could be used in conjunction with large array antennas for communication satellite systems. This will enable the simultaneous steering of high gain antenna beams in the direction of ground based users and the nulling of unwanted interference sources, such as radar systems, to be performed.

  13. Satellite communication protocols-a performance comparison considering on-board processing

    Microsoft Academic Search

    Ulrich Quernheim; Lehrstuhl fur Informatik IV

    1988-01-01

    A comparison is made of error control techniques for digital satellite communication by both analytical methods and simulations. Throughput and delays are studied as functions of the satellite channel bit error rate. Advantages of onboard processing (OBP) offered by future satellite systems are taken into consideration. It is shown that performance of link layer protocols on satellite links can be

  14. 47 CFR 101.1013 - Permissible communications services.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Local Multipoint Distribution Service § 101.1013 Permissible communications...Authorizations for stations in the Local Multipoint Distribution Service will be granted to provide services...

  15. 47 CFR 73.593 - Subsidiary communications services.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Section 73.593 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES Noncommercial...Broadcast Stations § 73.593 Subsidiary communications services. The licensee of a...

  16. 47 CFR 73.593 - Subsidiary communications services.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Section 73.593 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES Noncommercial...Broadcast Stations § 73.593 Subsidiary communications services. The licensee of a...

  17. 47 CFR 73.593 - Subsidiary communications services.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Section 73.593 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES Noncommercial...Broadcast Stations § 73.593 Subsidiary communications services. The licensee of a...

  18. On-orbit servicing for satellite upgrades

    E-print Network

    Joppin, Carole, 1979-

    2004-01-01

    Except for manned servicing operations using the Shuttle, there is no maintenance infrastructure for space systems. The traditional approach is to build in reliability and to replace the system in case of obsolescence or ...

  19. Simulation of downlink synchronization for a frequency-hopped satellite communication system

    Microsoft Academic Search

    Lyle Wagner

    1992-01-01

    Frequency hopped spread spectrum satellite communication systems provide robust communications resilient to many types and levels of jamming. Unfortunately, this increase in resilience is offset by an increase in complexity while establishing the communication link, termed synchronization. A two-step downlink synchronization method is examined, involving the transmission by satellite of synchronization hops that are modulated with a synchronization code and

  20. Description and results of a satellite laser communication\\/tracking simulation

    Microsoft Academic Search

    G. Stephen Mecherle; Kevin L. Marrs

    1994-01-01

    A detailed simulation of a satellite laser communication crosslink was developed to evaluate expected communication performance and sensitivity to steady-state and transient pointing and tracking errors caused by satellite disturbances. The interrelated effects of communication and tracking are modeled within the simulation in a “real time” Monte Carlo fashion. An overview of this simulation is presented along with current simulation

  1. Reliable Multicast Transport by Satellite: a Hybrid Satellite/Terrestrial Solution with Erasure Codes

    E-print Network

    Mailhes, Corinne

    multipoint communication service. In the context of reliable multicast communications, a new hybrid satellite/terrestrial approach is proposed. It aims at reducing the overall communication cost using satellite broadcasting onlyReliable Multicast Transport by Satellite: a Hybrid Satellite/Terrestrial Solution with Erasure

  2. Synchronization of system-of-systems interfaces in military satellite communications

    E-print Network

    Davis, Mark J. (Mark Jeffrey)

    2008-01-01

    Military systems continue to become more complex and nearly all are now part of one or more system of systems (SoS). Military satellite communications programs have expanded over the last decade from three distinct satellite ...

  3. Communication satellite technology, volume 4. Citations from the International Aerospace Abstracts data base

    NASA Technical Reports Server (NTRS)

    Zollars, G. F.

    1980-01-01

    The cited articles from the international literature concern all aspects of communication satellite technology. Included are articles on satellite networks, data transmission efficiency, time division multiple access, data links, and phase shift keying. This bibliography contains 239 citations.

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

    ERIC Educational Resources Information Center

    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…

  5. Two way satellite communication for telemetrology and remote control

    NASA Astrophysics Data System (ADS)

    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.

  6. High power microwave components for space communications satellite

    NASA Technical Reports Server (NTRS)

    Jankowski, H.; Geia, A.

    1972-01-01

    Analyzed, developed, and tested were high power microwave components for communications satellites systems. Included were waveguide and flange configurations with venting, a harmonic filter, forward and reverse power monitors, electrical fault sensors, and a diplexer for two channel simultaneous transmission. The assembly of 8.36 GHz components was bench tested, and then operated for 60 hours at 3.5 kW CW in a high vacuum. The diplexer was omitted from this test pending a modification of its end irises. An RF leakage test showed only that care is required at flange junctions; all other components were RF tight. Designs were extrapolated for 12 GHz and 2.64 GHz high power satellite systems.

  7. Serial MSK modem for the Advanced Communications Satellite Program

    NASA Technical Reports Server (NTRS)

    Stilwell, J. H.

    1982-01-01

    The design and test results of the 550-Mb/s, 110-Mb/s, and 27.5-Mb/s modems for the Advanced Communication Satellite Program are described. The TDMA/FDMA satellite environmental constraints have resulted in several unique features which include total acquisition times of 100 bit times and modem degradation of less than 1.5 dB at 10 to the -6th Pe. Key to the serial implementation of MSK is the resulting hardware simplicity and degradation insensitivity relative to conventionally implemented MSK and QPSK modems. The 110/27.5-Mb/s modems use an integrated circuit specifically developed for the program to perform the key carrier and clock-loop functions.

  8. Study of information transfer optimization for communication satellites

    NASA Technical Reports Server (NTRS)

    Odenwalder, J. P.; Viterbi, A. J.; Jacobs, I. M.; Heller, J. A.

    1973-01-01

    The results are presented of a study of source coding, modulation/channel coding, and systems techniques for application to teleconferencing over high data rate digital communication satellite links. Simultaneous transmission of video, voice, data, and/or graphics is possible in various teleconferencing modes and one-way, two-way, and broadcast modes are considered. A satellite channel model including filters, limiter, a TWT, detectors, and an optimized equalizer is treated in detail. A complete analysis is presented for one set of system assumptions which exclude nonlinear gain and phase distortion in the TWT. Modulation, demodulation, and channel coding are considered, based on an additive white Gaussian noise channel model which is an idealization of an equalized channel. Source coding with emphasis on video data compression is reviewed, and the experimental facility utilized to test promising techniques is fully described.

  9. Third International Satellite Direct Broadcast Services User's Conference

    NASA Technical Reports Server (NTRS)

    Kamowski, J.; Vermillion, C.

    1988-01-01

    A workshop titled, The Third International Satellite Direct Broadcast Services User's Conference, jointly sponsored by NASA and NOAA/NESDIS was scheduled to be held June 20 to 24, 1988, at the International Hotel located at the Baltimore-Washington Airport. Details concerning the organizing of the conference are given.

  10. Weather satellite products in the Flight Service Automation System (FSAS)

    Microsoft Academic Search

    J. Henline

    1984-01-01

    The activity discussed in this report was conducted to determine the acceptability and operational effectiveness of various techniques for displaying and distributing Weather Satellite Imagery within an Automated Flight Service Station (AFSS) environment. Primary consideration was given to the effectiveness of the displayed data together with the presentation format used for evaluations and demonstrations. Second, man-machine relationships and some hardware\\/software

  11. Advanced Communications Technology Satellite (ACTS) Used for Inclined Orbit Operations

    NASA Technical Reports Server (NTRS)

    Bauer, Robert A.

    2000-01-01

    The Advanced Communications Technology Satellite (ACTS) is operated by the NASA Glenn Research Center at Lewis Field 24 hours a day, 7 days a week. ACTS, which was launched in September 1993, is in its 7th year of operations, far exceeding the system s planned 2 years of operations and 4 years of designed mission life. After 5 successful years of operating as a geostationary satellite, the spacecraft s North-South stationkeeping was discontinued in August 1998. The system is now operating in an inclined orbit that increases at a rate of 0.8 /yr. With only scarce fuel remaining, operating in this mode extends the usage of the still totally functional payload. Although tracking systems are now needed on the experimenter Earth stations, experiment operations have continued with very little disruption. This is the only known geosynchronous Ka-band (30/20 GHz) spot-beam satellite operating in an inclined orbit. The project began its transition from geostationary operations to inclined operations in August 1998. This did not interrupt operations and was transparent to the experimenters on the system. For the space segment, new daily procedures were implemented to maintain the pointing of the system s narrow 0.3 spot beams while the spacecraft drifts in the North-South direction. For the ground segment, modifications were designed, developed, and fielded for the three classes of experimenter Earth stations. With the next generation of commercial satellite systems still being developed, ACTS remains the only operational testbed for Ka-band geosynchronous satellite communications over the Western hemisphere. Since inclined orbit operations began, the ACTS experiments program has supported 43 investigations by industry, Government, and academic organizations, as well as four demonstrations. The project s goals for inclined-orbit operations now reflect a narrower focus in the types of experiments that will be done. In these days of "faster, better, cheaper," NASA is seeking to gain greater relevance to the agency s mission from these experiments. One area that is of much interest both to NASA and the commercial world is the investigation of protocol issues related to the interoperability of satellites with terrestrial networks, such as Transmission Control Protocol/Internet Protocol (TCP/IP) and Asynchronous Transfer Mode (ATM) over wideband satellites. Other experiment areas of interest are supporting the U.S. Government and NASA as they begin using commercial space assets to meet their communications needs, evaluating issues related to operating a spot-beam satellite in inclined orbit, and evaluating new Ka-band hardware that requires a satellite link. ACTS is now in its last year of operations. Operations are planned through June 2000, when after 81 months of operations, this very successful spacecraft will be superorbited and made inert.

  12. Performance limitations of free-space optical communication satellite networks due to vibrations-analog case

    Microsoft Academic Search

    Shlomi Arnon; Norman S. Kopeika

    1997-01-01

    Free-space optical communication between satellites networked together can make possible high-speed communication between different places on earth. The use of optical radiation as a carrier between the satellites creates very narrow beam divergence angles. Due to the narrow-beam divergence angle and the large distance between the satellites, the pointing from one satellite to another is complicated. The complication is due

  13. Multiple reservation pipe-line polling for satellite packet communications

    NASA Astrophysics Data System (ADS)

    Ohsawa, T.; Furuya, Y.

    1992-03-01

    This paper proposes a new multiple access method for satellite communications, referred to as multiple reservation pipe-line polling (MRPP). This method is able to assign channels rapidly and change the frame length according to incoming traffic. Since the proposed scheme is collision-free,it is suitable for high traffic systems, such as computer networks, compared with access methods based on slotted ALOHA. Performance analysis shows that the MRPP is superior to ALOHA or TDMA for network size of a ten to few hundred stations.

  14. Transmitter experiment package for the communications technology satellite

    NASA Technical Reports Server (NTRS)

    Farber, B.; Goldin, D. S.; Marcus, B.; Mock, P.

    1977-01-01

    The operating requirements, system design characteristics, high voltage packaging considerations, nonstandard components development, and test results for the transmitter experiment package (TEP) are described. The TEP is used for broadcasting power transmission from the Communications Technology Satellite. The TEP consists of a 12 GHz, 200-watt output stage tube (OST), a high voltage processing system that converts the unregulated spacecraft solar array power to the regulated voltages required for OST operation, and a variable conductance heat pipe system that is used to cool the OST body.

  15. On-board packet switch architectures for communication satellites

    NASA Technical Reports Server (NTRS)

    Shalkhauser, Mary JO; Quintana, Jorge A.

    1993-01-01

    NASA Lewis Research Center is developing an on-board information switching processor for a multichannel communications signal processing satellite. The information switching processor is a flexible, high-throughput, fault tolerant, on-board baseband packet switch used to route user data among user ground terminals. Through industry study contracts and in-house investigations, several packet switching architectures were examined for possible implementation. Three contention-free switching architectures were studied in detail, namely the shared memory approach, the shared bus approach, and the shared memory per beam approach. These three switching architectures are discussed and the advantages and disadvantages of each approach are examined.

  16. A high gain antenna system for airborne satellite communication applications

    NASA Technical Reports Server (NTRS)

    Maritan, M.; Borgford, M.

    1990-01-01

    A high gain antenna for commercial aviation satellites communication is discussed. Electromagnetic and practical design considerations as well as candidate systems implementation are presented. An evaluation of these implementation schemes is given, resulting in the selection of a simple top mounted aerodynamic phased array antenna with a remotely located beam steering unit. This concept has been developed into a popular product known as the Canadian Marconi Company CMA-2100. A description of the technical details is followed by a summary of results from the first production antennas.

  17. 47 CFR 25.276 - Points of communication.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 false Points of communication. 25.276 Section 25.276 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Operations §...

  18. 47 CFR 25.276 - Points of communication.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 false Points of communication. 25.276 Section 25.276 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Operations §...

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

    NASA Technical Reports Server (NTRS)

    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.

  20. Status of NASA's Assessment of Satellite Servicing

    NASA Technical Reports Server (NTRS)

    Thronson, H. A.; Ahmed, M.; Townsend, J.; Whipple, A. L.; Oegerle, W. R.

    2010-01-01

    Following recommendations by the National Research Council, NASA's Authorization Act of 2008 (P.I. 110-422) and the Fiscal Year 2009 Omnibus Appropriations Act directed NASA to assess the feasibility of using the planned human spaceflight architecture to service existing and future observatory-class scientific spacecraft. This interest in space servicing, either with astronauts and/or with robots, reflects the decades-long success that NASA has achieved with the Space Shuttle program and the Hubble Space Telescope on behalf of the international astronomical community. This study is led by NASA Goddard Space Flight Center and will last about a year, leading to an assessment report to NASA and the science communities. We will report on the status of this study, progress toward goals, workshops, and priorities for the next few months.

  1. Demonstration of a Ka-Band communication path for On-Orbit Servicing

    NASA Astrophysics Data System (ADS)

    Purschke, R.; Harder, J.; Fleischner, A.

    2011-09-01

    The objectives of on-orbit servicing (OOS) missions include manipulation, proximity operations and inspection of target satellites. Therefore the servicer satellite often has to be teleoperated at low latency for several minutes to fulfill these tasks. That means communication plays a crucial role for OOS missions because real time teleoperation including high data rates has to be realized. So the communication path from front end sensors on the servicer spacecraft to the operator on ground has to be optimized and the latency time has to be minimized. Furthermore a long access time from the ground station is required because continuous communication with the satellite is mandatory for most of the OOS tasks. This can be realized by an inter-satellite link via a geostationary relay satellite, which has the advantage that a satellite in Low Earth Orbit (LEO) can be accessed from one ground station for about half an orbit. To evaluate both, the requirement of a long access time from the ground station as well as the need of a short latency time, an end to end communication scenario was implemented at the Institute of Astronautics (LRT) at the Technische Universität München (TUM). This scenario includes different spacecraft sensors (e.g. stereo cameras, LIDAR systems), a Ka-Band ground station and man machine interfaces. This paper describes the setup of a realistic simulation of a communication path from a data source to an operator via space-link. Furthermore the method of latency measuring depending on the data source is described. The communication architecture is embedded in a spacecraft simulator to simulate On-Orbit Servicing scenarios like Space Debris removal and target inspection.

  2. The 30/20 GHz fixed communications systems service demand assessment. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    Gamble, R. B.; Seltzer, H. R.; Speter, K. M.; Westheimer, M.

    1979-01-01

    Demand for telecommunications services is forecasted for the period 1980-2000, with particular reference to that portion of the demand associated with satellite communications. Overall demand for telecommunications is predicted to increase by a factor of five over the period studied and the satellite portion of demand will increase even more rapidly. Traffic demand is separately estimated for voice, video, and data services and is also described as a function of distance traveled and city size. The satellite component of projected demand is compared with the capacity available in the C and Ku satellite bands and it is projected that new satellite technology and the implementation of Ka band transmission will be needed in the decade of the 1990's.

  3. Olympus: Un satellite au service de l'education (Olympus: A Satellite in Service to Education).

    ERIC Educational Resources Information Center

    Lancien, Thierry

    1990-01-01

    Olympus, launched by Ariane in 1989, is the first European satellite to transmit an experimental educational and cultural program. The satellite is not only providing current programing but is testing the possibilities for distance education in the future. A schedule of humanities and science programing is presented. (MSE)

  4. Oceanic satellite data service system based on web

    NASA Astrophysics Data System (ADS)

    Kang, Yan; Pan, Delu; He, Xianqiang; Wang, Difeng; Chen, Jianyu; Chen, Xiaoyan

    2011-11-01

    The ocean satellite observation is more and more important to study the global change, protect ocean resource and implement ocean engineering for their large area cover and high frequency observation, which have already given us a global view of ocean environment parameters, including the sea surface temperature, ocean color, wind, wave, sea level and sea ice, etc... China has made great progress in ocean environment remote sensing over the last couple of years. These data are widely used for a variety of applications in ocean environment studies, coastal water quality monitoring environmental, fishery resources protection, development and utilization of fishery resources, coastal engineering and oceanography. But the data are no online information access and dissemination, no online visualization & browsing, no online query and analyze capability. To facilitate the application of the data and to help disseminating the data, a web-service system has developed. The system provides capabilities of online oceanic satellite information access, query, visualize and analyze. It disseminates oceanic satellite data to the users via real time retrieval, processing and publishing through standards-based geospatial web services. A region of interest can also be exported directly to Google Earth for displaying or downloaded. This web service system greatly improves accessibility, interoperability, usability, and visualization of oceanic satellite data without any client-side software installation.

  5. The EUTELSAT II satellites: Europe's seeds in communication and TV distribution game

    NASA Astrophysics Data System (ADS)

    Burgio, C.; Soula, J. L.; Dumesnil, J. J.

    1989-08-01

    The state-of-the-art satellite EUTELSAT II, developed by Aerospatiale and its industrial partners, is designed to provide Ku-band communication and television distribution services with 16 active channels accessible simultaneously to all users over the whole of Europe. Reconfigurable antenna-feed networks permits zoom operation on all 16 channels offering enhanced EIRP over the central part of Europe for TV distribution purposes. The satellite is designed to be fully operational during eclipse and to be compatible with Ariane IV. High satellite reliability and availability are achieved by the use of 8/12 amplifier ring redundancy during and beyond the 7 year life. The payload design makes use of only two antennas for all communications transmit and receive functions. This resulted in a great simplification of the repeater configuration and provides operational flexibility. The platform is directly derived from the Aerospatiale-MBB Spacebus 100 family (Arabsat heritage). Aerospatiale Telecommunications Programme Office, located in Cannes (France) is the prime contractor of the industrial team, Aeritalia, ATES, CASA, Contraves, Crouzet, ERA, ETCA, MBB, MSS, SEP. First flight model delivery in November 1989 has been a key factor in shaping both technical and management approaches to the programme.

  6. The 18/30 GHz fixed communications system service demand assessment. Volume 2: Main text

    NASA Technical Reports Server (NTRS)

    Gabriszeski, T.; Reiner, P.; Rogers, J.; Terbo, W.

    1979-01-01

    The total demand for communications services, and satellite transmission services at the 4/6 GHz, 12/14 GHz, and 18/30 GHz frequencies is assessed. The services are voice, video, and data services. Traffic demand, by service, is distributed by geographical regions, population density, and distance between serving points. Further distribution of traffic is made among four major end user groups: business, government, institutions and private individuals. A traffic demand analysis is performed on a typical metropolitan city to examine service distribution trends. The projected cost of C and Ku band satellite systems are compared on an individual service basis to projected terrestrial rates. Separation of traffic between transmission systems, including 18/30 GHz systems, is based on cost, user, and technical considerations.

  7. COMMENTS, AND LEGAL BRIEF AND COMMENTS, BEFORE THE FEDERAL COMMUNICATIONS COMMISSION, IN THE MATTER OF THE ESTABLISHMENT OF DOMESTIC NON-COMMON CARRIER COMMUNICATIONS-SATELLITE FACILITIES BY NON-GOVERNMENTAL ENTITIES, DOCKET 16495.

    ERIC Educational Resources Information Center

    Ford Foundation, New York, NY.

    VOLUME I OF THE FORD FOUNDATION SUBMISSION TO THE FEDERAL COMMUNICATIONS COMMISSION STATES THE FOUNDATION'S COMMITMENT TO EDUCATIONAL BROADCASTING, DESCRIBES THE SCOPE, SERVICES, COMPONENTS, AND COST OF A PROPOSED NATIONAL BROADCASTERS' NON-PROFIT SATELLITE SERVICE (BNS), ASSERTS THE SOCIAL, ECONOMIC, AND OPERATIONAL BENEFITS OF SUCH A SYSTEM, AND…

  8. Satellite broadcasting in Europe

    NASA Astrophysics Data System (ADS)

    Bartholome, P.

    1984-05-01

    Three main communications services are recognized by the International Telecommunications Union: the Fixed Service, the Mobile Service and the Broadcasting Service. In Europe, EUTELSAT has just begun to exploit the first ECS satellite. The ESA-launched satellite was originally designed to provide an international public telecommunication service, however, the satellite will be used now almost exclusively for TV program distribution, while a second ECS satellite will be used for telephony. Despite plans for the launch of a third, countries in Europe are looking to other organizations such as INTELSAT for greater satellite capacity. Other organizations include Unisat, DFS/Copernicus, GDL, and Videosat. Both satellite and cable networks will increase the program-viewing audience, thus encouraging plans for a pan-European television service intended for an international audience. Although the combination of cable networks and distribution satellites looks promising, high-power broadcasting satellites will play an important role because of flexibility and additional program distribution.

  9. Rearrangement procedures in regenerative multibeammobile communications satellites with frequency reuse

    NASA Technical Reports Server (NTRS)

    Colombo, Gianni; Settimo, Franco; Vernucci, Antonio

    1988-01-01

    After a short overview on the European tendencies about a Land Mobile Satellite Service, this paper describes an advanced system architecture, based on multiple spot-beams and on-board processing, capable of providing message and voice services over a wide European coverage, including some North-Africa and Middle-East countries. A remarkable problem associated with spot-beam configurations is the requirement for flexibility in the capacity offer to the various coverage areas. This means incorporating procedures for changing the on-board modulator-to-spot associations, respecting the constraints imposed by frequency reuse. After discussing the requirements of the rearrangement procedure, an on-purpose algorithm is presented. This paper is derived from work performed on contract to the European Space Agency (ESA).

  10. A spread-spectrum modem using constant envelope BPSK for a mobile satellite communications terminal

    NASA Technical Reports Server (NTRS)

    Iizuka, N.; Yamashita, A.; Takenaka, S.; Morikawa, E.; Ikegami, T.

    1990-01-01

    This paper describes a 5-kilobit/s spread spectrum modem with a 1.275 mega-Hz chip rate for mobile satellite communications. We used a Viterbi decoder with a coding gain of 7.8 dB at a BER of 10(exp -5) to decrease the required receiver power. This reduces the cost of communication services. The spread spectrum technique makes the modem immune to terrestrial radio signals and keeps it from causing interference in terrestrial radio systems. A class C power amplifier reduces the modem's power consumption. To avoid nonlinear distortion caused by the amplifier, the envelope of the input signal is kept constant by adding quadrature channel signal to the BPSK signal. To simulate the worst case, we measured the modem's output spectrum using a limiting amplifier instead of the class C amplifier, and found that 99 percent of the spectral power was confined to the specified 2.55 mega-Hz bandwidth.

  11. Fault tolerant onboard packet switch architecture for communication satellites: Shared memory per beam approach

    NASA Technical Reports Server (NTRS)

    Shalkhauser, Mary JO; Quintana, Jorge A.; Soni, Nitin J.

    1994-01-01

    The NASA Lewis Research Center is developing a multichannel communication signal processing satellite (MCSPS) system which will provide low data rate, direct to user, commercial communications services. The focus of current space segment developments is a flexible, high-throughput, fault tolerant onboard information switching processor. This information switching processor (ISP) is a destination-directed packet switch which performs both space and time switching to route user information among numerous user ground terminals. Through both industry study contracts and in-house investigations, several packet switching architectures were examined. A contention-free approach, the shared memory per beam architecture, was selected for implementation. The shared memory per beam architecture, fault tolerance insertion, implementation, and demonstration plans are described.

  12. SHF Cassegrain antenna with electronic beam squint tracking for high data rate mobile satellite communication systems

    Microsoft Academic Search

    B. Rama Rao; L. P. Callahan; R. J. Davis

    1994-01-01

    The design of pointing and tracking systems for vehicular antennas required for a high data rate mobile military satellite communication system is a daunting task because of its demanding requirements. Not only does the antenna have to be satellite pointed accurately towards the satellite as the vehicle moves rapidly and changes orientation, but it must also do so under scintillations

  13. Short communication Satellite-derived surface water pCO2 and airsea CO2 fluxes

    E-print Network

    Short communication Satellite-derived surface water pCO2 and air­sea CO2 fluxes in the northern China Sea in summer using satellite-derived sea surface temperatures (SSTs), chlorophyll-a (Chl a that the satellite-derived pCO2 was in general agreement with the in situ observations. The air­sea CO2 flux

  14. Calculated noise performance of a frequency hop sequence system with applications to low altitude satellite communications

    Microsoft Academic Search

    Mehmet T. Ozden

    1990-01-01

    This research considers communication amongst a community of earth terminals through a collection of low altitude earth oriented satellites (LASAT). In one proposed LASAT system, all satellites are identical and simultaneous transmission of near identical signals from several satellites creates interference at the earth receivers. Frequency hop sequence (FHS) is a new form of frequency hopping (FH) and is the

  15. Satellite and computer communications; Proceedings of the International Symposium, Versailles, France, April 27-29, 1983

    NASA Astrophysics Data System (ADS)

    Grange, J.-L.

    Various papers in the area of satellite and computer communications are presented. The general topics addressed include: satellite and local area networks, bulk transfer, transaction systems, satellite channel networks, on-board computers, link performance improvement, system management and design, and protocols and architecture.

  16. Mobile antenna system for Ku-band satellite Internet service

    Microsoft Academic Search

    Seong Ho Son; Ung Hee Park; Soon Ik Jeon; Chang Joo Kim

    2005-01-01

    This paper introduces the mobile antenna system for Ku-band satellite Internet service as well as DBS reception on the vehicle. The antenna type is an active phased array with mechanical rotation of which scanning range is the electronic ±10deg in elevation and the mechanical 360deg unlimited in azimuth. The G\\/T and EIRP are 7 dB\\/K and 34 dBW, respectively, and

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

    ERIC Educational Resources Information Center

    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)

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

    ERIC Educational Resources Information Center

    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…

  19. Ka-band propagation measurements: an opportunity with the Advanced Communications Technology Satellite (ACTS)

    Microsoft Academic Search

    ROBERT BAUER

    1997-01-01

    The Advanced Communications Technology Satellite (ACTS) was conceived at the National Aeronautics and Space Administration (NASA) as a follow on program to its long history in satellite communications projects that have reduced the risk of developing new technologies that fall outside the sponsorship capability of the private sector. To counter the foreign challenge that developed in the late 1970's to

  20. A new method of using preponderant terminal in cooperative satellite mobile communication system

    Microsoft Academic Search

    Jie Xiao; Feng Shaodong; Zhang Gengxin; Wang Fan

    2011-01-01

    In this paper, a new method of using pre- ponderant terminal in cooperative satellite mobile communication system was presented to reduce the influence of multipath fading and shading .First, the new method of using preponderant terminal in coopera- tive satellite mobile communication system was ana- lyzed?» then the system model was given and predi- gested to the typical three cooperative