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Sample records for e9 satellite communication

  1. 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…

  2. Satellite communications

    NASA Astrophysics Data System (ADS)

    Rubin, Philip A.

    A review of the economic and technological status of the satellite communications industry is presented. The history of satellite communications is outlined, focusing on the launching of Syncom III in 1963. The basic operation of communication satellites is explained. The differences between C and Ku frequency bands are examined. Economic issues related to satellite communications are discussed in detail.

  3. Satellite communications

    NASA Astrophysics Data System (ADS)

    Saha, M. K.

    1982-11-01

    The paper describes the basic principles and the historial development of satellite communications. Various satellite systems for global communications are discused and compared. Some typical operational communication satellite systems summary including geostationary systems are presented. Considerations leading to the system design including the link design for various multiple access techniques and the future trends in satellite communications systems are also discussed.

  4. Communications technology satellite

    NASA Technical Reports Server (NTRS)

    1976-01-01

    A description of the Communications Technology Satellite (CTS), its planned orbit, its experiments, and associated ground facilities was given. The communication experiments, to be carried out by a variety of groups in both the United States and Canada, include tele-education, tele-medicine, community interaction, data communications and broadcasting. A historical summary of communications satellite development was also included.

  5. China's satellite communications discussed

    NASA Astrophysics Data System (ADS)

    Ruhou, Z.

    1986-04-01

    In 1972, China began to enter the age of satellite comunications, and it was realized that satellites could play a large role in television transmission in China. The experimental broadcasting of satellite television programs was begun in 1978, and satisfactory results were obtained. The success of the television transmission demonstration has led to important decisions regarding development of a domestic satellite communications system. Before specialized communications satellites are launched, the decision was made to lease an international communications satellite transmitter. The responsibility of the ground stations were discussed.

  6. 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.

  7. Satellite communication antenna technology

    NASA Technical Reports Server (NTRS)

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

    1983-01-01

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

  8. Digital satellite communications

    NASA Astrophysics Data System (ADS)

    Ha, T. T.

    1986-06-01

    The use of satellite communications in point-to-multipoint transmission of data is studied. The theory, systems, and equipment for satellite communications are described. The topics of satellite orbits, satellite construction, earth station equipment, and the analysis of the satellite link are discussed. Different types of digital modulation for carrier transmission, and techniques for enhancing the transmission capacity, such as digital speech interpolation and demand assignment, are examined. Techniques and equipment for performing the multiple access-broadcasting functions including FDMA, TDMA, DAMA, CDMA, and random access are considered.

  9. Communication satellite applications

    NASA Astrophysics Data System (ADS)

    Pelton, Joseph N.

    The status and future of the technologies, numbers and services provided by communications satellites worldwide are explored. The evolution of Intelsat satellites and the associated earth terminals toward high-rate all-digital telephony, data, facsimile, videophone, videoconferencing and DBS capabilities are described. The capabilities, services and usage of the Intersputnik, Eutelsat, Arabsat and Palapa systems are also outlined. Domestic satellite communications by means of the Molniya, ANIK, Olympus, Intelsat and Palapa spacecraft are outlined, noting the fast growth of the market and the growing number of different satellite manufacturers. The technical, economic and service definition issues surrounding DBS systems are discussed, along with presently operating and planned maritime and aeronautical communications and positioning systems. Features of search and rescue and tracking, data, and relay satellite systems are summarized, and services offered or which will be offered by every existing or planned communication satellite worldwide are tabulated.

  10. 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…

  11. Advanced communications satellite systems

    NASA Technical Reports Server (NTRS)

    Sivo, J. N.

    1983-01-01

    There is a rapidly growing demand for satellite circuits, particularly for domestic service within the U.S. NASA's current program is aimed at developing the high risk, advanced satellite communications technologies required to significantly increase the capacity of future satellite communications systems. Attention is given to aspects of traffic distribution and service scenario, problems related to effects of rain attenuation, details regarding system configuration, a 30/20 GHz technology development approach, an experimental flight system, the communications payload for the experimental flight system, a typical experiment flight system coverage, and a typical three axis stabilized flight spacecraft.

  12. 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)

  13. Communication satellite technology trends

    NASA Technical Reports Server (NTRS)

    Cuccia, Louis

    1986-01-01

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

  14. 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…

  15. Advanced communications satellites

    NASA Technical Reports Server (NTRS)

    Sivo, J. N.

    1980-01-01

    The increase in demand for satellite communications services brought about shortages in available transponder capacity, especially at C-band. Interest shifted to the Ku-band frequency and currently carriers are rapidly moving to secure orbital slots for future satellite development. Projections of communications service demands over the next decade indiate growth in voice, data, and video services such that saturation of both C-band and Ku-band will occur by 1990. Emphasis must and will shift to Ka-band (20/30 GHz) frequency for fixed-satellite service. Advanced technologies such as multibeam antennas coupled with on-board satellite switching to allow implementation in this band of very high capacity satellite systems will be applied to meet the demand. Satellite system concepts that are likely in the 1990's and are likely to bring a new dimension to satellite delivered communication service are presented. The NASA 30/20 GHz communications satellite system demonstration program is discussed with emphasis on the related technology development.

  16. 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)

  17. 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.

  18. Satellite Communications for ATM

    NASA Technical Reports Server (NTRS)

    Shamma, Mohammed A.

    2003-01-01

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

  19. International communications via satellite

    NASA Astrophysics Data System (ADS)

    McLucas, J. L.

    The evolution of communications satellite systems is traced in terms of technical capabilities and technological advances. The Communications Act of 1962 led to the establishment of INTELSAT on an international basis in 1964. The original 19 signatory nations has grown to over 100, and over 800 ground relay stations have been built. The INTELSAT system comprises spacecraft over the Atlantic, Pacific, and Indian Oceans and handles 2/3 of the world's international electronic communications and all transoceanic television. The 1965 Early Bird satellite had a 240 two-way telephone link capacity and weighed 38 kg, while the Intelsat V satellites, of which there will be nine, have increased the capacity to 20,000 voice circuits and Intelsat VI will double the number by 1993. Increasing demand for satellite communications links is driving the design and development of space platforms for multiple missions of communications, meteorological studies, and on-board switching and data processing in excess of current multiple satellite systems.

  20. Land mobile communications satellite

    NASA Astrophysics Data System (ADS)

    Carnebianca, C.; Pavesi, B.; Tuozzi, A.

    1986-09-01

    The economic value and salient technical and operational characteristics of a European Land Mobile Communication Satellite (LMCS) to complement and supplement the demand for mobile services of Western European countries in the 1995 to 2005 time frames were assessed. A significant future expansion of demand for LCMS services on the part of the public is anticipated. Important augmentations of current service capabilities could be achieved by a satellite service, improving the overall system performances and/or assisting the PTT's in containing their investments in the required infrastructure. The satellite service itself could represent a profitable revenue producer.

  1. Overview of commercial satellite communications

    NASA Astrophysics Data System (ADS)

    Beakley, G. W.

    1984-07-01

    A brief history of communications satellites is presented, taking into account the launching of Sputnik 1 in October 1957, the Explorer 1 in January of 1958, the launch of the Score as the world's first active communications satellite in December 1958, the Communications Satellite Act in 1962, and the launch of 'Early Bird' in 1964. The Intelsat satellites are considered along with maritime satellite communications, the U.S. domestic satellite systems, Alaskan satellite communications, cable television, broadcast TV stations, print media, the hotel/motel industry as a large market for satellite communications terminals, the opening of a minicable and satellite master antenna TV market for TV receive-only systems, and business telecommunications earth terminals. Attention is also given to future directions regarding satellite positions, the concept of 'video-plus', and direct broadcast satellites.

  2. ESA's satellite communications programme

    NASA Astrophysics Data System (ADS)

    Bartholome, P.

    1985-02-01

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

  3. 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.

  4. 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)

  5. Public service satellite communications

    NASA Technical Reports Server (NTRS)

    Wolff, E. A.

    1978-01-01

    It is suggested that the high effective isotropic radiated power provided by high-power satellite transmitters and high-gain antennas could be used in conjunction with economical ground receivers to furnish public services in remote areas of the U.S. Applications to health care, education and public safety are mentioned. A system concept involving a communications satellite operating in the Ku-band (12-GHz down, 14-GHz up) and either 100/30 watt stationary earth terminals with 1-1.8 m antennas or mobile terminals with omnidirectional antennas is presented.

  6. Experimental Satellite Quantum Communications

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

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

  7. Experimental Satellite Quantum Communications.

    PubMed

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

    2015-07-24

    Quantum communication (QC), namely, the faithful transmission of generic quantum states, is a key ingredient of quantum information science. Here we demonstrate QC with polarization encoding from space to ground by exploiting satellite corner cube retroreflectors as quantum transmitters in orbit and the Matera Laser Ranging Observatory of the Italian Space Agency in Matera, Italy, as a quantum receiver. The quantum bit error ratio (QBER) has been kept steadily low to a level suitable for several quantum information protocols, as the violation of Bell inequalities or quantum key distribution (QKD). Indeed, by taking data from different satellites, we demonstrate an average value of QBER=4.6% for a total link duration of 85 s. The mean photon number per pulse μ_{sat} leaving the satellites was estimated to be of the order of one. In addition, we propose a fully operational satellite QKD system by exploiting our communication scheme with orbiting retroreflectors equipped with a modulator, a very compact payload. Our scheme paves the way toward the implementation of a QC worldwide network leveraging existing receivers. PMID:26252672

  8. Synergy in satellite communication

    NASA Astrophysics Data System (ADS)

    Sachdev, D. K.

    1989-10-01

    After presenting a development history for satellite communications systems demonstrating the extent to which synergistic, efficiency-enhancing interactions between emerging technologies form the basis for much of the economic feasibility of these efforts, an evaluation is made of prospective synergisms. Among those identified as uniquely promising are the interactions of electric propulsion and Ni-H batteries, and of onboard data processing/bulk demultiplexing. An attempt is made to furnish a stimulus for system designers to actively seek out synergies rather than wait passively until they emerge.

  9. Optical satellite communications in Europe

    NASA Astrophysics Data System (ADS)

    Sodnik, Zoran; Lutz, Hanspeter; Furch, Bernhard; Meyer, Rolf

    2010-02-01

    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 own satellite. Since 2008 the German Space Agency (DLR) is operating an inter-satellite link between the NFIRE and TerraSAR-X satellites based on a second generation of laser communication technology, which will be used for the new European Data Relay Satellite (EDRS) system to be deployed in 2013.

  10. 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.

  11. Satellite personal communications system

    NASA Technical Reports Server (NTRS)

    Reilly, N. B.; Smith, J. G. (Inventor)

    1980-01-01

    Voice channel communication between low power mobile stations dispersed over a large area is provided by a system which includes a geostationary satellite utilizing a large UHF antenna that can receive a transmission from a caller and retransmit it over any one beam of a matrix of narrow beams, so the chosen beam covers an area in which a designated called party is located. A single up-link control channel occupying a narrow frequency band, can be utilized to receive dial up signals from a caller, and another single down link control channel can be utilized to ring up the called party located anywhere within the continental United States. The satellite antenna includes a matrix of feed horns that not only direct the beams in a controlled matrix onto the area of the continental United States, but also permit detection of the region from which the caller's signal is transmitted and the region from which the called party's answer is received, to enable the interconnection of signals received from these two regions. The system is particularly useful for rural areas.

  12. Communications satellites - The experimental years

    NASA Astrophysics Data System (ADS)

    Edelson, B. I.

    1983-10-01

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

  13. Communications satellites - The experimental years

    NASA Technical Reports Server (NTRS)

    Edelson, B. I.

    1983-01-01

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

  14. Trends in mobile satellite communication

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  15. [Theme Issue: Communications Satellites.

    ERIC Educational Resources Information Center

    Howkins, John, Ed.

    1976-01-01

    One section of this journal is devoted to issues involving broadcast satellites. Separate articles discuss the need for international planning of satellite broadcasting, decisions made at the 1971 World Administrative Radio Conference for Space Telecommunications, potential problems in satellite broadcasting, a series of proposals drawn up by the…

  16. 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.

  17. Advanced Communications Technology Satellite (ACTS)

    NASA Astrophysics Data System (ADS)

    Gedney, Richard T.; Schertler, Ronald J.

    1989-06-01

    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.

  18. Coding for reliable satellite communications

    NASA Technical Reports Server (NTRS)

    Gaarder, N. T.; Lin, S.

    1986-01-01

    This research project was set up to study various kinds of coding techniques for error control in satellite and space communications for NASA Goddard Space Flight Center. During the project period, researchers investigated the following areas: (1) decoding of Reed-Solomon codes in terms of dual basis; (2) concatenated and cascaded error control coding schemes for satellite and space communications; (3) use of hybrid coding schemes (error correction and detection incorporated with retransmission) to improve system reliability and throughput in satellite communications; (4) good codes for simultaneous error correction and error detection, and (5) error control techniques for ring and star networks.

  19. 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.

  20. Adaptive arrays for satellite communications

    NASA Technical Reports Server (NTRS)

    Gupta, I. J.; Ksienski, A. A.

    1984-01-01

    The suppression of interfering signals in a satellite communication system was studied. Adaptive arrays are used to suppress interference at the reception site. It is required that the interference be suppressed to very low levels and a modified adaptive circuit is used which accomplishes the desired objective. Techniques for the modification of the transmit patterns to minimize interference with neighboring communication links are explored.

  1. Odyssey personal communications satellite system

    NASA Technical Reports Server (NTRS)

    Spitzer, Christopher J.

    1993-01-01

    The spectacular growth of cellular telephone networks has proved the demand for personal communications. Large regions of the world are too sparsely populated to be economically served by terrestrial cellular communications. Since satellites are well suited to this application, TRW filed with the FCC on May 31, 1993 for the Odyssey construction permit. Odyssey will provide high quality wireless communication services worldwide from satellites. These services will include: voice, data, paging, and messaging. Odyssey will be an economical approach to providing communications. A constellation of 12 satellites will be orbited in three, 55 deg. inclined planes at an altitude of 10,354 km to provide continuous coverage of designated regions. Two satellites will be visible anywhere in the world at all times. This dual visibility leads to high line-of-sight elevation angles, minimizing obstructions by terrain, trees and buildings. Each satellite generates a multibeam antenna pattern that divides its coverage area into a set of contiguous cells. The communications system employs spread spectrum CDMA on both the uplinks and downlinks. This signaling method permits band sharing with other systems and applications. Signal processing is accomplished on the ground at the satellite's 'Gateway' stations. The 'bent pipe' transponders accommodates different regional standards, as well as signaling changes over time. The low power Odyssey handset will be cellular compatible. Multipath fade protection is provided in the handset.

  2. Satellite communication for public services

    NASA Technical Reports Server (NTRS)

    Cooper, R. S.; Redisch, W. N.

    1977-01-01

    Public service programs using NASA's ATS-6 and CTS satellites are discussed. Examples include the ATS-6 Health and Education Telecommunications experimental program and the use of CTS to enable students in one university to take courses presented at another distant university. Possible applications of satellite communication systems to several areas of public service are described, and economic and political obstacles hindering the implementation of these programs are considered. It is suggested that a federally sponsored program demonstrating the utility of satellites accomodating a large number of small terminals is needed to encourage commercial satellite operations.

  3. Baseband Processor for Communication Satellites

    NASA Technical Reports Server (NTRS)

    Jirberg, Russell J.; Armstrong, Patrick C.

    1987-01-01

    Baseband processing (BBP) system for advanced satellite communications successfully demonstrated. Provides increased data capacity through frequency-reusing multibeam antenna systems, using time-division multiple access (TDMA) and onboard satellite switching. Large numbers of thin-route trunking stations and user-based Earth terminals handled efficiently by satellite baseband switching. With BBP system, satellite routes data messages individually among locations anywhere in continental United States. Processes, controls, and routes message traffic among users. Time-division multiple access and baseband switching used.

  4. NASA compendium of satellite communications programs

    NASA Technical Reports Server (NTRS)

    1971-01-01

    A comprehensive review of worldwide satellite communication programs is reported that ranges in time from the inception of satellite communications to mid-1971. Particular emphasis is placed on program results, including experiments conducted, communications system operational performance, and technology employed.

  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. Ion propulsion for communications satellites

    NASA Technical Reports Server (NTRS)

    Poeschel, R. L.

    1984-01-01

    In a recent study of potential applications for electric propulsion, it was determined that ion propulsion can provide North-South stationkeeping (NSSK) for communication satellites in geosynchronous orbit with appreciably less mass than chemical propulsion. While this finding is not new, the margin of benefit over advanced chemical propulsion technology depends strongly on the ion propulsion system specifications. Full advantage must be taken of the under-utilized stored energy available from the communication satellite's batteries. This paper describes a methodology for evaluating the benefits obtained in using ion propulsion for NSSK, both in terms of the mass reduction and its economic value.

  7. 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.

  8. Telemammography Using Satellite Communications

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Telemammography, the electronic transmission of digitized mammograms, can connect patients with timely, critical medical expertise; howev er, an adequate terrestrial communications infrastructure does not exist in these areas. NASA Lewis Research Center's Advanced Space Commu nications Laboratory is now working with leading breast cancer resear ch hospitals, including the Cleveland Clinic and the University of Virginia, to perform the critical research necessary to allow new satell ite networks to support telemammography.

  9. 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)

  10. 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.

  11. Ephemeris representations for communications satellites

    NASA Astrophysics Data System (ADS)

    Proulx, R. J.; Cefola, P. J.; McClain, W. D.

    1984-08-01

    Large orbit determination (OD) centers are the primary source of artificial satellite ephemeris data. The ephemeris message of the OD facility contains implicitly the predicted satellite trajectory. The user can recover ephemeris data on the basis of two conceptual approaches. The current investigation is concerned with an alternative solution to the ephemeris representation problem. According to the procedure employed in this case, the mean equinoctial element time histories corresponding to the predicted satellite trajectory generated by the OD facility are approximated by low degree Legendre polynomials to represent their secular behavior and by trigonometric terms to represent their mean periodic behavior. This approach provides a simple, low cost, and accurate ephemeris representation, which satisfies the potential autonomy requirements for Military Satellite Communications.

  12. 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.

  13. 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.

  14. 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.

  15. Trends in NASA communication satellites.

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

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

  16. Electric propulsion for communications satellites

    NASA Technical Reports Server (NTRS)

    Free, B. A.; Guman, W. J.; Herron, B. G.; Zafran, S.

    1978-01-01

    Electric propulsion systems derive their low overall mass, relative to chemical propulsion systems, from an optimized mix of independently controlled power and mass flow rate. A significant reduction in mass can be secured by substituting electric propulsion for conventional hydrazine systems for all the major propulsion tasks of a communications satellite. Additional advantages for all electric propulsion maneuvers are precision location and higher pointing accuracy. Three auxiliary electric propulsion systems are now available for application on communications satellites: the electrically augmented hydrazine system, the Teflon pulsed plasma system, and the mercury ion thruster system. Primary electric propulsion will be available in the mid to late 1980s as a spin-off of NASA's program of interplanetary exploration.

  17. Satellite-Based Quantum Communications

    SciTech Connect

    Hughes, Richard J; Nordholt, Jane E; McCabe, Kevin P; Newell, Raymond T; Peterson, Charles G

    2010-09-20

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

  18. 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).

  19. China's future domestic satellite communications systems

    NASA Astrophysics Data System (ADS)

    Liang, G.; Yaokun, Y.

    1985-01-01

    Some ideas about China's future domestic satellite communications system are discussed. The following objectives are considered in the design of the new domestic satellite communications system: (1) the satellite communications system should link the entire country and form a unified national network with the existing ground communications system, (2) based on the geographic situation, the satellite communications system should be primarily small and scattered in the west, and large and concentrated in the east, (3) the Telephone business should be the primary business of the satellite communications system. It should also be capable of transmitting television, telegram, data, facsimile, and broadcasting, (4) the communications system should be primarily designed as a single jump system. It should not exceed two jumps, and (5) the parameters of the communications system should be in agreement with CCIR and CCITT recommendations.

  20. 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.

  1. A new wave of communication satellites

    NASA Technical Reports Server (NTRS)

    Lovell, R. R.; Cuccia, C. L.

    1984-01-01

    Satellites provide at present telephone, television, data, and business services on a national, regional, and international scale, and the geostationary arc has become crowded at C-band (6/4 GHz) and Ku-band (14/11 GHz) frequencies. The evolution and the present state of satellite communications are discussed along with details regarding the development of direct broadcast satellites, the position of Canada with respect to satellite communications, Japanese developments, ESA and Eutelsat, aspects of collaboration between France and Germany regarding communications satellites, the United Kingdom, and the Nordic countries.

  2. Mobile satellite service communications tests using a NASA satellite

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

  3. The Impact of Satellites on Cable Communications.

    ERIC Educational Resources Information Center

    Chayes, Abram

    Two recent developments in communications satellite technology may speed the coming of cable TV (CATV) networks. First, increases in satellite power are reducing the cost of ground stations. Second, a connection between one ground station, the satellite, and any other ground station is no longer necessarily fixed. Now one station can communicate…

  4. NASA Compendium of Satellite Communications Programs

    NASA Technical Reports Server (NTRS)

    1973-01-01

    A comprehensive review is presented of worldwide communication programs that range in time from the inception of satellite communications to August 1971. The programs included are: Echo, Courier, West Ford, Telstar, Relay, Syncom, Lincoln experimental satellites, Intelsat, Tacsat, Skynet, Nato system, and Telesat.

  5. Federal Research and Development for Satellite Communications.

    ERIC Educational Resources Information Center

    National Academy of Sciences - National Research Council, Washington, DC. Assembly of Engineering.

    This report of the Committee on Satellite Communications (COSC) reviews a number of future communication needs which could be satisfied by satellite systems, including needs in fields such as education, health care delivery, hazard warning, navigation aids, search and rescue, electronic mail delivery, time and frequency dissemination, and…

  6. 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…

  7. Telemedicine using mobile satellite communication.

    PubMed

    Murakami, H; Shimizu, K; Yamamoto, K; Mikami, T; Hoshimiya, N; Kondo, K

    1994-05-01

    With a view to providing paramedical care within moving vehicles, a telemedicine technique using mobile satellite communication was proposed. With this technique, the diagnosis from a specialist and the emergency care under his/her instructions would be available on the spot without unnecessary delay. The characteristic problems of this technique were identified as: channel capacity, size of the system, reliability of vital sign transmission, real-time operation and electromagnetic interference. Measures against these problems were devised, and their effectiveness was analyzed. A data format was designed and an experimental system was developed. The system can simultaneously transmit a color image, an audio signal, 3 channels ECG and blood pressures from a mobile station to a ground station. It can transmit an audio signal and error control signals from a ground station to a mobile station in a full duplex mode. Fundamental transmission characteristics were measured in a fixed station. Finally, experiments of medical data transmission were conducted with a navigating ship and an aircraft flying an international route. The measured threshold values of C/N(o) to guarantee satisfactory data reception were well below the lower boundary of C/N(o) of the communication link. Consequently, the feasibility of this technique was verified. PMID:8070809

  8. 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.

  9. NASA compendium of satellite communications programs

    NASA Technical Reports Server (NTRS)

    1975-01-01

    A comprehensive review is given of worldwide satellite communication programs that range in time from the inception of satellite communications to mid-1974. Particular emphasis is placed on program results, including experiments conducted, communications system operational performance, and technology employed. The background for understanding these results is established through brief summaries of the program organization, system configuration, and satellite and ground terminal characteristics. Major consideration is given to the communications system aspects of each program, but general spacecraft technology and other experiments conducted as part of the same program are mentioned summarily.

  10. 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.

  11. Emerging technologies for communication satellite payloads

    NASA Astrophysics Data System (ADS)

    Yüceer, Mehmet

    2012-04-01

    Recent developments in payload designs will allow more flexible and efficient use of telecommunication satellites. Important modifications in repeater designs, antenna structures and spectrum policies open up exciting opportunities for GEO satellites to support a variety of emerging applications, ranging from telemedicine to real-time data transfer between LEO satellite and ground station. This study gives information about the emerging technologies in the design of communication satellites' transceiver subsystem and demonstrates the feasibility of using fiber optic links for the local oscillator distribution in future satellite payloads together with the optical inter-satellite link.

  12. Economics of satellite communications systems

    NASA Astrophysics Data System (ADS)

    Pritchard, Wilbur L.

    This paper is partly a tutorial, telling systematically how one goes about calculating the total annual costs of a satellite communications system, and partly the expression of some original ideas on the choice of parameters so as to minimize these costs. The calculation of costs can be divided into two broad categories. The first is technical and is concerned with estimating what particular equipment will cost and what will be the annual expense to maintain and operate it. One starts in the estimation of any new system by listing the principal items of equipment, such as satellites, earth stations of various sizes and functions, telemetry and tracking equipment and terrestrial interfaces, and then estimating how much each item will cost. Methods are presented for generating such estimates, based on a knowledge of the gross parameters, such as antenna size, coverage area, transmitter power and information rate. These parameters determine the system performance and it is usually possible, knowing them, to estimate the costs of the equipment rather well. Some formulae based on regression analyses are presented. Methods are then given for estimating closely related expenses, such as maintenance and operation, and then an approximate method is developed for estimating terrestrial interconnection costs. It is pointed out that in specific cases when tariff and geographical information are available, it is usually better to work with specific data, but nonetheless it is often desirable, especially in global system estimating, to approximate these interconnect costs without recourse to individual tariffs. The procedure results in a set of costs for the purchase of equipment and its maintenance, and a schedule of payments. Some payments will be incurred during the manufacture of the satellite and before any systems operation, but many will not be incurred until the system is no longer in use, e.g. incentives. In any case, with the methods presented in the first section, one

  13. Satellite communications for disaster relief operations

    NASA Technical Reports Server (NTRS)

    Sivo, J. N.

    1979-01-01

    The use of existing and planned communication satellite systems to provide assistance in the implementation of disaster relief operations on a global basis was discussed along with satellite communications system implications and their potential impact on field operations in disaster situations. Consideration are given to the utilization of both INTELSAT and MARISAT systems operating at frequencies ranging from 1.5 to 4 GHz and to the size and type of ground terminals necessary for satellite access. Estimates of communication requirements for a global system are given. Some discussion of cost estimates for satellite services to support operations are included. Studies of communication satellites for both pre and post disaster applications conducted for NOAA are included as well as recent experiments conducted in conjunction with the Office of Foreign Disaster Assistance of the Agency for International Development.

  14. Activities of Canadian Satellite Communications, Inc.

    NASA Astrophysics Data System (ADS)

    1992-12-01

    Canadian Satellite Communications (Cancom) has as its core business the provision of television and radio signals to cable systems in Canada, with the objective of making affordable broadcast signals available to remote and/or small communities. Cancom also provides direct-to-home services to backyard receiving dishes, as well as satellite digital data business communications services, satellite business television, and satellite network services. Its business communication services range from satellite links for big-city businesses with small branch operations located far from major centers, to a mobile messaging and tracking system for the trucking industry. Revenues in 1992 totalled $48,212,000 and net income was just over $7 million. Cancom bought 10 percent interest in Leosat Corp. of Washington, DC, who are seeking approval to operate a position locator network from low-orbit satellites. Cancom has also become a partner in SovCan Star Satellite Communications Inc., which will build an international satellite system in partnership with Russia. The first satellite in this east-west business network will be placed in a Russian orbital slot over the Atlantic by 1996, and a second satellite will follow for the Pacific region. This annual report of Cancom's activities for 1992 includes financial statements and a six year financial review.

  15. NASA's Advanced Communications Technology Satellite (ACTS)

    NASA Technical Reports Server (NTRS)

    Gedney, R. T.

    1983-01-01

    NASA recently restructured its Space Communications Program to emphasize the development of high risk communication technology useable in multiple frequency bands and to support a wide range of future communication needs. As part of this restructuring, the Advanced Communications Technology Satellite (ACTS) Project will develop and experimentally verify the technology associated with multiple fixed and scanning beam systems which will enable growth in communication satellite capacities and more effective utilization of the radio frequency spectrum. The ACTS requirements and operations as well as the technology significance for future systems are described.

  16. Digital, Satellite-Based Aeronautical Communication

    NASA Technical Reports Server (NTRS)

    Davarian, F.

    1989-01-01

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

  17. Giant step for communication satellite technology

    NASA Technical Reports Server (NTRS)

    Lovell, R. R.

    1984-01-01

    NASA's communications program, which is concerned with advanced communications technology, reflects the need for operational communications satellite capacity beyond the capabilities of current technology and the unwillingness of private industry in the U.S. to undertake making the required long-range, high-risk technology advances. It is pointed out that current satellites will not satisfy the forecasted demand for additional capacity in the 1990s and beyond. Current technology exists primarily up to 18 GHz. Designing a communications satellite at each of the three major uplink/downlink frequency bands (C, Ku, and Ka, 6/4 GHz, 14/11 GHz, and 30/20 GHz, respectively) presents different program management and technical problems. Increasing frequency or power can be done only by intensive sustained research. This is the rationale for NASA to pursue the Advanced Communications Technology Satellite (ACTS) program.

  18. A forecast of broadcast satellite communications

    NASA Technical Reports Server (NTRS)

    Martino, J. P.; Lenz, R. C., Jr.

    1977-01-01

    This paper presents forecasts of likely changes in broadcast satellite technology, the technology of ground terminals, and the technology of terrestrial communications competitive with satellites. The impacts of these changes in technology are then assessed, using a cross-impact model of U.S. domestic telecommunications, to determine the consequences of various possible changes in communications satellite technology. These consequences are discussed in terms of various possible services, for households, businesses, and specialized customers, which might become economically viable as a result of improvements in satellite technology.

  19. 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.

  20. Domestic satellite communications systems - Background and projections

    NASA Astrophysics Data System (ADS)

    Bargellini, P. L.

    Planned and existing national and international communications satellites are reviewed, along with comparative costs for leasing or owning a satellite and the basic capabilities of communications spacecraft. Eleven different satellite communications systems existed in 1982, including Intelsat, Marisat/Inmarsat, and Intersputnik as the international segments, and the Molniya, Telesat, Palapa, Westar, Satcom, Comstar, Amersat, and the SBS national systems. Seven of the twenty countries leasing Intelsat services are planning their own satellites. Leasing permits full capabilities withno development costs and ensures the lessor of full use of the satellite capacities. Developing countries can then gain hands-on experience with space technologies. Future demands are discussed, noting the broadening of the available bandwidths, better orbit utilization, and increases in transponder numbers to handle increased loads in future spacecraft.

  1. Experimental millimeter-wave satellite communications system

    NASA Astrophysics Data System (ADS)

    Shimada, Masaaaki; Suzuki, Yoshiaki; Arimoto, Yoshinori; Inoue, Akihiko; Kobayashi, Hideki; Okubo, Naofumi

    A 43/38 GHz (mm-wave) bands satellite communications experimental system featuring GEO/LEO and GEO/GEO intersatellite communications and personal communications is discussed in light of detailed performance data on the electrical model of the mm-wave transponder. Attention is given to the state-of-the-art solid-state power amplifiers, low-noise amplifiers, and personal communications terminal employed in these experiments.

  2. STS-5 deployment of communications satellites

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The Telesat Canada ANIK C-3 communications satellite rises from its protective 'cradle' (obscured by another such device in the foreground) in the cargo bay of the Space Shuttle Columbia. The empty, closed shield in the cargo bay (foreground) earlier had protected Satellite Business Systems (SBS-3) satellite. Both orbital maneuvering system (OMS) pods, part of the vertical tail and part of the wing stand out in this photo.

  3. 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.

  4. 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.

  5. 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…

  6. 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.

  7. Introduction to Satellite Communications Technology for NREN

    NASA Technical Reports Server (NTRS)

    Stone, Thom

    2004-01-01

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

  8. 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.

  9. 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…

  10. Protected transitional solution to transformational satellite communications

    NASA Astrophysics Data System (ADS)

    Brand, Jerry C.

    2005-06-01

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

  11. 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.

  12. 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.

  13. A small terminal for satellite communication systems

    NASA Technical Reports Server (NTRS)

    Xiong, Fuqin; Wu, Dong; Jin, Min

    1994-01-01

    A small portable, low-cost satellite communications terminal system incorporating a modulator/demodulator and convolutional-Viterbi coder/decoder is described. Advances in signal processing and error-correction techniques in combination with higher power and higher frequencies aboard satellites allow for more efficient use of the space segment. This makes it possible to design small economical earth stations. The Advanced Communications Technology Satellite (ACTS) was chosen to test the system. ACTS, operating at the Ka band incorporates higher power, higher frequency, frequency and spatial reuse using spot beams and polarization.

  14. 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.

  15. Deployment of the SBS-4 communications satellite

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Deployment of the SBS-4 communications satellite by the STS 41-D crew. The cylindrical spacecraft spins and rises from the its protective shield in the space shuttle payload bay. Behind it is another, closed protective cradle for the Syncom IV communications satllite. The earth's surface can be seen to the left of the frame.

  16. 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.

  17. 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…

  18. 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…

  19. USDA Forest Service mobile satellite communications applications

    NASA Technical Reports Server (NTRS)

    Warren, John R.

    1990-01-01

    The airborne IR signal processing system being developed will require the use of mobile satellite communications to achieve its full capability and improvement in delivery timeliness of processed IR data to the Fire Staff. There are numerous other beneficial uses, both during wildland fire management operations or in daily routine tasks, which will also benefit from the availability of reliable communications from remote areas.

  20. 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…

  1. Intelsat communications satellite scheduled for launch

    NASA Technical Reports Server (NTRS)

    1983-01-01

    To be placed into a highly elliptical transfer orbit by the Atlas Centaur (AC-61) launch vehicle, the INTELSAT V-F satellite has 12,000 voice circuits and 2 color television channels and incorporates a maritime communication system for ship to shore communications. The stages of the launch vehicle and the launch operations are described. A table shows the launch sequence.

  2. 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

  3. 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.

  4. Communications satellites in non-geostationary orbits

    NASA Technical Reports Server (NTRS)

    Price, Kent M.; Doong, Wen; Nguyen, Tuan Q.; Turner, Andrew E.; Weyandt, Charles

    1988-01-01

    The design of a satellite communications system in an orbit lower than GEO is described. Two sun-synchronous orbits which lie in the equatorial plane have been selected: (1) the apogee at constant time-of-day equatorial orbit, a highly eccentric orbit with five revolutions per day, which allows 77-135 percent more satellite mass to be placed in orbit than for GEO; and (2) the sun-synchronous 12-hour equatorial orbit, a circular orbit with two revolutions per day, which allows 23-29 percent more mass. The results of a life cycle economic analysis illustrate that nongeostationary satellite systems could be competitive with geostationary satellite systems.

  5. 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.

  6. 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.

  7. ECS - The European Communication Satellite system

    NASA Astrophysics Data System (ADS)

    Wooster, C. B.

    1981-09-01

    The evolution of the European Communication Satellite system (ECS) is traced from feasibility studies in 1970 to the development and launch in 1978 of the Orbital Test Satellite (OTS) by the European Space Agency to prove the new satellite and radio transmission technology being used on ECS. This was followed by the establishment of 'Interim EUTELSAT' in 1979 as the organization to operate ECS. The satellite, which operates at 11/14 GHz, covers all the capitals in Europe via three spot beam antennas, supplemented by a 'Eurobeam' regional coverage antenna which extends the range to cover all of Europe and the Mediterranean basin. Telephony channels are transmitted digitally using time division multiple access (TDMA) with digital speech interpolation (DSI) to optimize satellite capacity. Television transmission is by analog FM over the Eurobeam antenna to North African as well as European capitals. System implications of TDMA operation are discussed, and the EUTELSAT policy for Special Services or satellite business systems is discussed.

  8. 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.

  9. Engineers checkout Early Bird-Communication Satellite

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Engineers Stanley R. Peterson (left) and Ray Bowerman (right), checkout the Early Bird, the world's first communication satellite. NASA launched the satellite built by Hughes Aircraft Corporation on April 6, 1955 at 6:48pm E.S.T. from Complex 17a at Cape Kennedy, Florida. Early Bird was built for the Communications Satellite Corporation and weighed about 85 pounds after being placed in a synchronous orbit of 22,300 miles above the earth. It was positioned over the Atlantic to provide 240 two-way telephone channels or 2-way television between Europe and North America. The outer surface of Early Bird was covered with 6,000 silicon-coated solar cells, which absorbed the sun's rays to provide power to the satellite for its intricate transmitting and receiving equipment.

  10. Communications satellites - Countdown for INTELSAT VI

    NASA Astrophysics Data System (ADS)

    Pollack, L.; Weiss, H.

    1984-02-01

    Microwave technology development over the last 20 years has expanded the transmission bandwidth/satellite in earth-synchronous orbit from 50 to more than 3000 MHz. Solar cell, electrical battery, stationkeeping and microwave amplification technology advancements have increased satellite service lives from 1.5 years to 10. The INTELSAT geostationary communications satellites which are scheduled for introduction into the global system in 1986 will have the capacity for 40,000 telephone channels, as well as two TV programs. The satellite generation beyond that of 1986, which is currently in the design stage for expanded capacity, will be needed by the mid-1990s to meet traffic demand and is projected to incorporate such features as 20- and 30-GHz communications, onboard signal processing and switching, and more bandwidth-efficient modulation.

  11. The NASA Advanced Communications Technology Satellite (ACTS)

    NASA Astrophysics Data System (ADS)

    Beck, G. A.

    1984-10-01

    Forecasts indicate that a saturation of the capacity of the satellite communications service will occur in the U.S. domestic market by the early 1990s. In order to prevent this from happening, advanced technologies must be developed. NASA has been concerned with such a development. One key is the exploitation of the Ka-band (30/20 GHz), which is much wider than C- and Ku-bands together. Another is the use of multiple narrow antenna beams in the satellite to achieve large frequency reuse factors with very high antenna gains. NASA has developed proof-of-concept hardware components which form the basis for a flight demonstration. The Advanced Communications Technology Satellite (ACTS) system will provide this demonstration. Attention is given to the ACTS Program definition, the ACTS Flight System, the Multibeam Communications Package, and the spacecraft bus.

  12. Mobile satellite communications in the Forest Service

    NASA Technical Reports Server (NTRS)

    Warren, John R.

    1988-01-01

    There are usually some places within a forest that do not have adequate communication coverage due to line-of-sight or other reasons. These areas are generally known by the foresters and radio technicians and allowances are made for that when working or traveling in those areas. However, when wildfire or other emergencies occur, communications are vital because wildfires can require hundreds of firefighters and cover thousands of acres. During these emergency operations, the existing communications are not adequate and complete radio systems are moved into the area for the conduct of fire communications. Incident command posts (ICPs) and fire camps are set up in remote locations and there is constant need for communications in the fire area and to agency headquarters and dispatch offices. Mobile satellite communications would be an ideal supplement to the Forest Service's current communications system in aiding forest fire control activities.

  13. Regulations of satellite communications in Argentina

    NASA Astrophysics Data System (ADS)

    Elia, Jose A. S.

    1993-10-01

    The paper describes the Argentine Government regulation policy in the telecommunications field, when, in 1989 the government adopted the strategy of freeing the State from all economic activities that could be operated by the private sector, including the National Telecommunications Company. Particular attention is given to the Argentine Government policy in the international activities of satellite telecommunications and the satellite projects in the Argentine Republic. These include the LUSAT-1 microsatellite, developed by the members of the Argentine Amateur Satellites organization and launched by NASA in 1990; the SAC-B satellite, to be launched in 1996, which will carry devices developed in Argentina to measure astronomical phenomena; and the NAHUEL, a privately financed domestic communications satellite, which will be developed without state intervention via subsidies or exclusiveness.

  14. Millimeter-wave personal satellite communications experiment

    NASA Astrophysics Data System (ADS)

    Arimoto, Yoshinori; Suzuki, Yoshiaki; Miura, Ryu; Shiomi, Tadashi; Iid, Takashi

    1987-10-01

    The concept of experimental millimeter-wave (43/38 GHz) satellite communications systems is discussed, and five demonstrative applications (a portable video phone system, a portable news gathering and distribution system, an observation data transmission system, a communication system for the Asia-Oceanian region, and a mobile information service system) are considered. A millimeter-wave satellite transponder for ETS-VI (to be launched in 1992) is described, in addition to the frequency selection in the millimeter wave band. Key elements of the component design, including the receiver front-end, the local oscillator, and the solid state power amplifier, are also discussed.

  15. Viewpoints on control of military satellite communications

    NASA Astrophysics Data System (ADS)

    Heppe, S. B.

    1983-07-01

    The three main factors are system management, communication protocols, and the control system architecture. Each of these is analyzed here in terms of a model. The model for system management is the definition of system control of the Defense Communications System, referred to as DCS syscon. The model for communication protocols is referred to as the ISO model of OSI, ISO denoting the International Standards Organization and OSI denoting open systems interconnection. The model of the control system architecture is an elemental model. The interplay between the models is highlighted. Examples are presented from the Defense Satellite Communications System and from MILSTAR. Prospects for the future are considered in view of the integration expected as systems become more capable and sophisticated. It is expected that many of the real-time control functions performed at the worldwide and theater levels will be automated on the satellite.

  16. 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.

  17. Satellite communications in Canada: A DOC perspective

    NASA Astrophysics Data System (ADS)

    Stursberg, Richard

    The role of the Canadian government and, in particular, of the Department of Communications (DOC) in the evolution and growth of the Canadian communications satellite industry is discussed. Activities by DOC which affect communications technology include the following: (1) DOC undertakes research and development of enabling technologies; (2) promotes the use and diffusion of these technologies through applications development; (3) negotiates spectrum and orbit arrangements in the domestic and international arena; (4) assists in the promotion and marketing of Canadian technologies abroad; and (5) has overall responsibility of telecommunications policy including development of standards and regulations. A brief description is provided of global factors which are expected to affect technology and applications development in the near future. Strategic program reviews undertaken by the Satellite Communications Application Program, the research and development program, and the Government Telecommunications Agency are described.

  18. European small geostationary communications satellites

    NASA Astrophysics Data System (ADS)

    Sun, Wei, , Dr.; Ellmers, Frank; Winkler, Andreas; Schuff, Herbert; Sansegundo Chamarro, Manuel Julián

    2011-04-01

    Hispasat Advanced Generation 1 (HAG1) is the first satellite using the SGEO platform, which is under the development in the ESA Artes-11 program. Since the last presentation in the IAC 2007, a European industrial consortium led by OHB has completed the mission and spacecraft design. The platform Preliminary Design Review has been carried out in May 2008. The customer for the first mission is a commercial operator—Hispasat. The contract was signed in December 2008 and the satellite will be launched in 2012. To give confidence to the customer, SGEO platform will use up to date flight proven technologies. HAG1 carries 20/24 Ku-band and 3/5 Ka-band transponders to provide commercial services. Some innovative payload technologies will also be flown on board of HAG1 to gain in-orbit heritage. SGEO has also been selected as the baseline platform for the ESA Data Relay Satellite (EDRS). Phase-A study has just kicked off in January 2009. The targeted launch date is 2013. Heinrich Hertz will also use the SGEO platform. Heinrich Hertz is funded by the German Space Agency (DLR) and provides flight opportunities for technologies and components developed by the German Space Industry. With the HAG1 contract in hand, and EDRS and Heinrich Hertz in the line, OHB with its partners has the confidence that it will be able to speed up the product development of the SGEO platform for potential customers in the commercial market. This paper will first present the updated platform design and the status of the product development will be followed with the introduction of innovative payload technologies on board the first mission—HAG1 and ended with the mission concepts of EDRS and Heinrich Hertz missions.

  19. Odyssey, an optimized personal communications satellite system

    NASA Astrophysics Data System (ADS)

    Rusch, Roger J.

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

  20. Odyssey, an optimized personal communications satellite system

    NASA Astrophysics Data System (ADS)

    Rusch, Roger J.

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

  1. Deployment of the Telstar communications satellite

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Deployment of the Telstar communications satellite by the STS 41-D crew. The cylindrical spacecraft spins and rises past the shuttle stabilizer from its protective shield in the space shuttle payload bay. Behind it is another, closed protective cradle. Heavy clouds cover much of the water and land mass of earth in the background.

  2. Mobile satellite communications - Vehicle antenna technology update

    NASA Technical Reports Server (NTRS)

    Bell, D.; Naderi, F. M.

    1986-01-01

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

  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. 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.

  5. Communications satellite system for Africa

    NASA Astrophysics Data System (ADS)

    Kriegl, W.; Laufenberg, W.

    1980-09-01

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

  6. Future developments in aeronautical satellite communications

    NASA Technical Reports Server (NTRS)

    Wood, Peter

    1990-01-01

    Very shortly aeronautical satellite communications will be introduced on a world wide basis. By the end of the year, voice communications (both to the cabin and cockpit) and packet data communications will be available to both airlines and executive aircraft. During the decade following the introduction of the system, there will be many enhancements and developments which will increase the range of applications, expand the potential number of users, and reduce costs. A number of ways in which the system is expected to evolve over this period are presented. Among the issues which are covered are the impact of spot beam satellites, spectrum and power conservation techniques, and the expanding range of user services.

  7. Technology requirements for post-1985 communications satellites

    NASA Technical Reports Server (NTRS)

    Burtt, J. E.; Moe, C. R.; Elms, R. V.; Delateur, L. A.; Sedlacek, W. C.; Younger, G. G.

    1973-01-01

    The technical and functional requirements for commercial communication satellites are discussed. The need for providing quality service at an acceptable cost is emphasized. Specialized services are postulated in a needs model which forecasts future demands. This needs model is based upon 322 separately identified needs for long distance communication. It is shown that the 1985 demand for satellite communication service for a domestic region such as the United States, and surrounding sea and air lanes, may require on the order of 100,000 MHz of bandwith. This level of demand can be met by means of the presently allocated bandwidths and developing some key technologies. Suggested improvements include: (1) improving antennas so that high speed switching will be possible; (2) development of solid state transponders for 12 GHz and possibly higher frequencies; (3) development of switched or steered beam antennas with 10 db or higher gain for aircraft; and (4) continued development of improved video channel compression techniques and hardware.

  8. A baseline maritime satellite communication system

    NASA Technical Reports Server (NTRS)

    Durrani, S. H.; Mcgregor, D. N.

    1974-01-01

    This paper describes a baseline system for maritime communications via satellite during the 1980s. The system model employs three geostationary satellites with global coverage antennas. Access to the system is controlled by a master station; user access is based on time-ordered polling or random access. Each Thor-Delta launched satellite has an RF power of 100 W (spinner) or 250 W (three-axis stabilized), and provides 10 equivalent duplex voice channels for up to 1500 ships with average waiting times of approximately 2.5 minutes. The satellite capacity is bounded by the available bandwidth to 50 such channels, which can serve up to 10,000 ships with an average waiting time of 5 minutes. The ships must have peak antenna gains of approximately 15.5 dB or 22.5 dB for the two cases (10 or 50 voice channels) when a spinner satellite is used; the required gains are 4 dB lower if a three-axis stabilized satellite is used. The ship antenna requirements can be reduced by 8 to 10 dB by employing a high-gain multi-beam phased array antenna on the satellite.

  9. Some design considerations for planetary relay communications satellites.

    NASA Technical Reports Server (NTRS)

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

    1966-01-01

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

  10. Some design considerations for planetary relay communications satellites.

    NASA Technical Reports Server (NTRS)

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

    1966-01-01

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

  11. Deployment of the RCA Satcom K-2 communications satellite

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The 4,144 pound RCA Satcom K-2 communications satellite is deployed from the cargo bay of the Shuttle Atlantis during the STS 61-B mission. The closed cradle of the Morelos communications satellite is seen just below it.

  12. 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.

  13. Potential markets for advanced satellite communications

    NASA Astrophysics Data System (ADS)

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

    1993-09-01

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

  14. Propulsion requirements for communications satellites.

    NASA Technical Reports Server (NTRS)

    Isley, W. C.; Duck, K. I.

    1972-01-01

    The concept of characteristics thrust is introduced herein as a means of classifying propulsion system tasks related particularly to geosynchronous communications spacecraft. Approximate analytical models are developed to permit estimation of characteristic thrust for injection error corrections, orbit angle re-location, north-south station keeping, east-west station keeping, spin axis precession control, attitude rate damping, and orbit raising applications. Performance assessment factors are then outlined in terms of characteristic power, characteristic weight, and characteristic volume envelope, which are related to the characteristic thrust. Finally, selected performance curves are shown for power as a function of spacecraft weight, including the influence of duty cycle on north-south station keeping, a 90 degree orbit angle re-location in 14 days, and finally comparison of orbit raising tasks from low and intermediate orbits to a final geosynchronous station. Power requirements range from less than 75 watts for north-south station keeping on small payloads up to greater than 15 KW for a 180 day orbit raising mission including a 28.5 degree plane change.

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

    NASA Technical Reports Server (NTRS)

    Ikegami, Tetsushi

    1989-01-01

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

  16. Adaptive antenna arrays for satellite communication

    NASA Technical Reports Server (NTRS)

    Gupta, Inder J.

    1989-01-01

    The feasibility of using adaptive antenna arrays to provide interference protection in satellite communications was studied. The feedback loops as well as the sample matric inversion (SMI) algorithm for weight control were studied. Appropriate modifications in the two were made to achieve the required interference suppression. An experimental system was built to test the modified feedback loops and the modified SMI algorithm. The performance of the experimental system was evaluated using bench generated signals and signals received from TVRO geosynchronous satellites. A summary of results is given. Some suggestions for future work are also presented.

  17. Lens Antenna For Mobile/Satellite Communication

    NASA Technical Reports Server (NTRS)

    Bodnar, D. G.; Rainer, B. K.

    1988-01-01

    Flat, compact antenna made of stripline elements aimed at fixed elevation angle but steered electronically in azimuth. Design simplified by maintaining fixed elevation and relying on width of beam to cover desired elevation range. Need for phase shifter at each radiating element eliminated by arranging elements in circles and feeding through stripline disks called "R-KR lenses". Used in Mobile/Satellite Service, antenna mounted on top of vehicle on Earth and used to keep transmitted and received antenna beams aimed approximately toward communication satellite.

  18. A native IP satellite communications system

    NASA Astrophysics Data System (ADS)

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

    2004-08-01

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

  19. 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.

  20. Satellite switched FDMA advanced communication technology satellite program

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

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

  1. An advanced domestic satellite communications system

    NASA Technical Reports Server (NTRS)

    1980-01-01

    An updated traffic projection for U.S. domestic satellite communications service covering a period of 15 years; mid-1980 to mid-1995 was prepared. This model takes into account expected technology advances and reductions in transmission costs, legislative and regulatory changes permitting increased competition, and rising energy costs which will encourage more extensive substitution of telecommunications for travel. The historical development and current status of satellite systems are discussed as well as the characteristics of follow-on systems. Orbital arc utilization, spacecraft configuration for single shuttle launch, Earth station configuration, and system costs are examined. Areas which require technology development include multiple beam frequency reuse antennas, on-board switching, intersatellite links, and ka-band operation. Packing and deployment schemes for enclosing the satellite within the shuttle orbiter bay must also be devised.

  2. Cost effective launch technology for communications satellites

    NASA Astrophysics Data System (ADS)

    Taylor, T. C.; Overman, A.

    1984-10-01

    The present investigation is concerned with the possibility to reduce the costs for placing satellites in orbit by making use of an 'Air Launch' system. It is pointed out that the launching of rockets to orbit from aircraft in flight has been done successfully. It is suggested to modify the existing technology for the purpose of launching communications satellites and other payloads to orbit. Thus, the Air Launch Concept combines aircraft and missile technologies to produce a method of transport to orbit. A heavy lift cargo aircraft is employed to fly a rocket and the satellite payload to a specific location at the service ceiling of the aircraft. Attention is given to aspects of cost reduction, commercial and technical benefits, the anticipated market, and technical details.

  3. World-wide aeronautical satellite communications

    NASA Technical Reports Server (NTRS)

    Wood, Peter; Smith, Keith

    1988-01-01

    INMARSAT decided to expand the spectrum covered by its new generation of satellites, INMARSAT-2, to include 1 MHz (subsequently increased to 3 MHz) of the spectrum designed for aeronautical use. It began a design study that led to the specifications for the system that is now being implemented. Subsequently, INMARSAT awarded contracts for the design of avionics and high gain antennas to a number of manufactures, while several of the signatories that provide ground equipment for communicating with the INMARSAT satellites are modifying their earth stations to work with the avionic equipment. As a resullt of these activities, a world-wide aeronautical satellite system supporting both voice and data will become operational in 1989.

  4. DCS/FTS Commercial Satellite Communications System

    NASA Astrophysics Data System (ADS)

    Shimabukuro, T.; Rosner, R.; Pearsall, C.

    In order to control the rising costs of telephonic services and meeting the increasing demand for wideband video and data services within U.S. Federal Government agencies, the Defense Communications Agency and the General Services Administration have begun the implementation of a leased Commercial Satellite Communications System. Service volume demand, commonality of service requirements, and common geographic communities of interest facilitate economies of scale in the course of meeting DOD and other Federal agencies' objectives. The service, which incorporates the Federal Telecommunications Service and is therefore designated DCS/FTS, is presently studied with respect to military and national objectives.

  5. Federal research and development for satellite communications

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A Committee on Satellite Communication (COSC) was formed under the auspices of the Space Applications Board (SAB) in order to study Federal research and development on satellite communications (SC). Discussion on whether to continue the research and development and the proper role of the Federal Government are addressed. Discussion focussed on six possible options for a Federal role in SC research and development: (1) the current NASA SC program; (2) an expanded NASA SC technology program; (3) a SC technology flight test support program; (4) an experimental SC technology flight program; (5) an experimental public service SC system program; and (6) an operational public service SC system program. Decision criteria and recommendations are presented.

  6. 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.

  7. Servicing communication satellites in geostationary orbit

    NASA Technical Reports Server (NTRS)

    Russell, Paul K.; Price, Kent M.

    1990-01-01

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

  8. Voice intelligibility in satellite mobile communications

    NASA Technical Reports Server (NTRS)

    Wishna, S.

    1973-01-01

    An amplitude control technique is reported that equalizes low level phonemes in a satellite narrow band FM voice communication system over channels having low carrier to noise ratios. This method presents at the transmitter equal amplitude phonemes so that the low level phonemes, when they are transmitted over the noisey channel, are above the noise and contribute to output intelligibility. The amplitude control technique provides also for squelching of noise when speech is not being transmitted.

  9. Compendium of communication and broadcast satellites 1958 to 1980

    NASA Astrophysics Data System (ADS)

    Brown, M. P., Jr.

    Communications satellites frequency allocation bands are listed for the periods before and after WARC-79, and family trees for communications satellites are provided, along with stabilization mechanisms and launch sites and dates for all communications satellites from 1960 to 1980. The physical characteristics and operational parameters of experimental satellites such as the ATS, BS, Courier, CS, CTS, Echo, ECS, ETS II, OTS, Relay, Score, Sirio, Symphonie, Syncom, Telstar, and West Ford satellites are given, with respective signal switching flow diagrams. Finally, the OSCAR (AMSAT) satellites, as well as the Soviet RS amateur satellites are described.

  10. Domestic satellite communications - The Canadian experience

    NASA Astrophysics Data System (ADS)

    Golden, D. A.

    1980-09-01

    The history of commercial satellite communications in Canada is surveyed. The benefits provided by the existing system are illustrated by focusing on the experience of a particular Arctic hamlet (Pangnirtung). Attention is given to the factors that have differentiated the Canadian system from the American one (smaller, less homogenous, and more widely dispersed population). The problem posed by 'pirate' earth stations in Canada is discussed. An account is given of the origin of the dual-band Anik B (6/4 GHz and 14/12 GHz channels) satellite series, and the experiments (telemedicine, tele-education, communication with remote communities) carried out with the Anik B are discussed. Attention is also given to the promising results obtained in the direct-to-home TV service delivered by Anik B. Plans for the Anik C (16 channels 14/12 GHz frequency band) and Anik D (24 channels 6/4 GHz frequency band) series are discussed. Canada's communications needs are such that the continued development of satellite systems seems assured.

  11. United States societal experiments via the Communications Technology Satellite

    NASA Technical Reports Server (NTRS)

    Donoughe, P. L.

    1976-01-01

    After a brief description of the Communication Technology Satellite and its U.S. coverage, the U.S. societal experiments via the CTS are discussed. These include education (college curriculum sharing, and project interchange), health care (biomedical communications, health communications, and communication support for decentralized education), and community and special experiments (satellite library information network, and transportable earth terminal).

  12. Transmitter microdischarges in communications and broadcast Satellites

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

  13. Packet message communication system using polar orbiting small satellites

    NASA Astrophysics Data System (ADS)

    Suzuki, Ryutaro; Suzuki, Yoshiaki; Arimoto, Yoshinori; Ohmori, Shingo; Kondo, Kimio

    A packet message communication system using small satellites is studied for the worldwide electronic mail type communications. A store and forward type packet communication equipment is installed in a small satellite which rotates in the polar orbit. By using the inter satellite link among the small satellites and/or the data exchange earth station in the polar region, the delay time of the packet message delivery can be shortened. The multibeam phased array technique is applied for the satellite antenna in order to increase the link quality. Four satellites configuration gives a 4.8 kbps data rate message with less than two hours of delay.

  14. Engineering calculations for communications satellite systems planning

    NASA Technical Reports Server (NTRS)

    Reilly, C. H.; Levis, C. A.; Mount-Campbell, C.; Gonsalvez, D. J.; Wang, C. W.; Yamamura, Y.

    1985-01-01

    Computer-based techniques for optimizing communications-satellite orbit and frequency assignments are discussed. A gradient-search code was tested against a BSS scenario derived from the RARC-83 data. Improvement was obtained, but each iteration requires about 50 minutes of IBM-3081 CPU time. Gradient-search experiments on a small FSS test problem, consisting of a single service area served by 8 satellites, showed quickest convergence when the satellites were all initially placed near the center of the available orbital arc with moderate spacing. A transformation technique is proposed for investigating the surface topography of the objective function used in the gradient-search method. A new synthesis approach is based on transforming single-entry interference constraints into corresponding constraints on satellite spacings. These constraints are used with linear objective functions to formulate the co-channel orbital assignment task as a linear-programming (LP) problem or mixed integer programming (MIP) problem. Globally optimal solutions are always found with the MIP problems, but not necessarily with the LP problems. The MIP solutions can be used to evaluate the quality of the LP solutions. The initial results are very encouraging.

  15. Polarization Tracking Study of Earth Station in Satellite Communications

    NASA Astrophysics Data System (ADS)

    Ma, Lihua; Hu, Chao; Pei, Jun

    2016-01-01

    Satellite communications, in telecommunications, the use of satellite can provide communications links between various points on the earth. Typical satellite communication is composed of a communication satellite, a signal transmitter and a signal receiver. As the signal transmitter or the signal receiver, an earth station plays a vital role in the satellite communications. Accurately adjustment of antenna azimuth, elevation and polarization angles on the earth station is the key to satellite communications. In the present paper, a study of polarization tracking of earth station is presented, and a detailed adjustment procession of the polarization angle is given. Combing with observation series of MEASAT-2 satellite in geostationary orbit, the polarization tracking accuracy is verified. The method can be embeded into computer program of antenna polarization adjustment in earth station.

  16. Discussion on the progress and future of satellite communication (Japan)

    NASA Technical Reports Server (NTRS)

    Ogata, M.; Mizusawa, H.; Irie, K.

    1985-01-01

    The current status of communications satellite development in Japan is presented. It is shown that beginning with research on satellite communucations in the late 1950's, progress was made in the areas of communications, remote sensing, and technology experimentation. The current status of communication satellites is presented, stressing development in the areas of CFRP construction elements, the use of LSI and MIC circuits, advanced multibeam antenna systems, Ku and Ka band transmission systems, and the shift to small-scale earth stations. Methods for reducing costs and increasing transmission efficiency are shown. The technical specifications of all satellite projects currently under development are given. Users of Japanese communications satellite are presented.

  17. 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…

  18. 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.

  19. Low-noise amplifiers for satellite communications

    NASA Astrophysics Data System (ADS)

    Whelehan, J.

    1984-02-01

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

  20. An optimization model of communications satellite planning

    NASA Astrophysics Data System (ADS)

    Dutta, Amitava; Rama, Dasaratha V.

    1992-09-01

    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 (CPS). 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, greatly reducing the need for heuristic choices of parameter values; (3) effects of physical and regulatory constraints are included; and (4) the effects of market prices for transmission capacity on planning variables are explicitly captured. The model is solved optimally using geometric programming methods. Sensitivity analysis yields coefficients, analogous to shadow prices, that quantitatively indicate the change in objective function value resulting from variations in input parameter values. This helps in determining the robustness of planning decisions and in coping with some of the uncertainty that exists at the planning stage. The model can therefore be useful in making economically viable planning decisions for communications satellites.

  1. 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.

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

    NASA Technical Reports Server (NTRS)

    Shiomi, Tadashi

    1988-01-01

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

  3. 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.

  4. Evolution of the Defense Satellite Communications System

    NASA Astrophysics Data System (ADS)

    Brandon, W. T.

    Concepts for the next generation of the Defense Satellite Communications System (DSCS) are outlined. The approach is to improve the 7/8 GHz capability rather than evolve directly to extremely high frequency (EHF) (either 30/20 or 44/20 GHz). This approach eases transition problems, extends the useful life of the super high frequency (SHF) ground segment, and simultaneously improves system endurance and connectivity. The basic approach is to introduce dual polarization and extend frequency coverage of military terminals to the commercial Ku band.

  5. Satellite Communications with NRAO Green Bank Antennas

    NASA Astrophysics Data System (ADS)

    Ford, John M.; Ford, H. Alyson; Watts, Galen

    2014-11-01

    The National Radio Astronomy Observatory's Green Bank facility has several medium and large antennas that are available for satellite communications. The 100 meter Robert C. Byrd Green Bank Telescope (GBT), the largest and most sensitive antenna on site, is capable of receiving signals at frequencies as high as 86 GHz. In addition to the GBT are the fully operational 43 meter, 20 meter, and 13.7 meter antennas, and three mothballed 26 meter antennas. A transmitter could be fitted to any of these antennas for spacecraft uplinks. We discuss the characteristics of these antennas and possible operational models for future planetary science mission support.

  6. Apple - Indian experimental geostationary communication satellite

    NASA Astrophysics Data System (ADS)

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

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

  7. The 'INMARSAT' international maritime satellite communication system

    NASA Astrophysics Data System (ADS)

    Atserov, Iu. S.

    1982-12-01

    The history, design, operating characteristics, achievements, and prospects of INMARSAT are discussed. More than 1300 ships are presently equipped to operate within the system, and this number is expected to rise to about 5000 by 1986. The principle of operation involves single coordinating earth stations allocating telephone channels in their zones between other earth stations. The messages reach a common signalling channel with which all ship stations keep in touch. The ship stations are connected to the international telex network. The INMARSAT system enables ships in the automated mode of operation to establish telephone and telegraph comunication with any subscriber on the shore of any country. The quality of the communication is practically independent of the distance between ship and shore at any time of year and under any meteorological conditions. Estimates indicate that the use of satellite communication with ships reduces losses from accidents by 10 percent per year.

  8. Comparison of INMARSAT and ATS3 satellite communication

    SciTech Connect

    Not Available

    1993-03-29

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

  9. Preparation to optical communication experiments with geostationary satellite ARTEMIS

    NASA Astrophysics Data System (ADS)

    Kuzkov, V. P.; Medveskij, M. M.; Yatskiv, D. Ya.; Nedashkovskij, V. N.; Suberlak, V. R.; Glushchenko, Yu. M.; Peretyatko, M. M.; Eremenko, N. A.

    2003-08-01

    We considered necessary conditions and performed expedient calculations for performing laser communication link experiments with geostationary satellite ARTEMIS (ESA). The scheme was proposed of performing these experiments by using two telescopes. The results of observation of the satellite are presented.

  10. Domestic satellite communication system to be established in China

    NASA Astrophysics Data System (ADS)

    Ruhou, Z.; Yucheng, B.

    1984-01-01

    The establishment of a domestic satellite communication system for China is discussed. To experiment, China built miniaturized ground stations and used the idle transponders of two INTELSAT satellites. The experiment was divided into three phases: verification and test of ground facilities; test of channel operations; and functional test of the Chinese built ground facilities. From a technical and economic point of view, developing China's domestic satellite communication system by leasing foreign satellites and building China's own ground stations is both efficient and effective.

  11. Communications satellites - Orbiting into the '90s

    NASA Astrophysics Data System (ADS)

    Campanella, S. Joseph

    1990-08-01

    Engineering advances in satellite communications are discussed, including sophisticated switchboards, narrow beams, source coding for higher-capacity networks, and the use of higher- and lower-frequency bands and lower orbits. One of the most popular new 14/11-14/12-GHz commercial services has been time-division multiplexing of multiple carriers operating at low to medium bit rates. Multiple-carrier, low-burst-rate TDMA is widely used with VSATs on the customer's premises. NASA's ACTS and Italy's Italsat both plan to use signal regeneration at 30/20 GHz. Onboard switching and multiplexing minimize noise, boost power, but also trim the cost of the entire satellite network. Phone calls and voiceband data are now often carried over satellite circuits and by cable beneath the ocean by adaptive differential pulse-coded modulation (ADPCM). When this technique at 32 kb/s is combined with digital speech interpolation, circuits can carry 4-5 times as many channels as with conventional 64-kb/s pulse-coded transmission.

  12. Optical antenna in laser inter-satellite communication

    NASA Astrophysics Data System (ADS)

    Wen, Chuanhua; Wang, Chunxia; Li, Yuquan

    2005-02-01

    In the modern world of telecommunications, the concept of wireless global coverage is of the utmost importance. 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. In recent years, laser links for inter-satellites communication are becoming more and more important. Laser communication systems operate in a frequency range above the regulated spectrum. Laser provides many advantages for using in point-to-point ISLs (inter-satellites links) such as for links between satellites and spacecraft in deep space. Such advantages include: high speed; high bandwidth; small antenna size; narrow field of view; and narrow antenna beam. These advantages combined with the advantages in fiber optic components (optical preamplifiers, multiplexers, detectors, etc) have made laser attractive for laser links. Now we can bring WDM (wavelength-division multiplexing) to emerging broadband satellite communication systems. By using the common antenna system and ATP (Aiming, Tracking and Pointing) system, the satellites will get more capacity. In the inter-satellites laser communication, the important performances of the systems such as BER and BL both have direct relation with the optical systems. The optical systems have the function of ATP. The optical antenna is the most important component of the optical system. So the optical antenna is an important key technology to the inter-satellites laser communication. In this paper, we mainly study the optical system in the inter-satellites laser communication. we compare with three kinds of optical antennas: refractor and reflector and Catadioptrics of the passive optical system; we also analyze the effect of bandwidth to the WDM communication systems; we use the correlative software, simulate the curves of the performance of the optical antennas. These

  13. 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.

  14. Satellite communications at the Goddard Space Flight Center

    NASA Technical Reports Server (NTRS)

    Clark, J. F.; Redisch, W. N.

    1976-01-01

    Starting with the 1960 Delta launch of the first Echo satellite, NASA's Goddard Space Flight Center (GSFC) became one of the pioneers in satellite communications. Attention is given to the project Syncom, the Applications Technology Satellite (ATS) program, the ATS-6 project, and current GSFC efforts. After the decision announced in January of 1973 that NASA would phase out of communications satellite programs, the communications effort at GSFC concentrates on the operation of ATS spacecraft in orbit, experiments in the 12- to 14 GHz frequency band, and advanced communications research.

  15. a System Design and Analysis for Satellite Communication Link

    NASA Astrophysics Data System (ADS)

    Chung, Tae-Jin; Eun, Jong-Won

    2000-12-01

    A satellite RF communication link is analyzed based on a simple fundamental equations by systematic approach in this paper. The number of variables related to a design and analysis of satellite RF link is often a dozen or more, thus it is a tedious and time-consuming task. With the given input data, the important parameters are calculated step by step and three communication characteristics such as communication channel capacity, carrier-to-noise ratio (CNR) at the satellite and ground station are analyzed. It gives very useful information to the system engineers for designing and analyzing the overall satellite communication system in the conceptual design phase.

  16. 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.

  17. 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.

  18. Communications satellite systems operations with the space station, volume 2

    NASA Technical Reports Server (NTRS)

    Price, K.; Dixon, J.; Weyandt, C.

    1987-01-01

    A financial model was developed which described quantitatively the economics of the space segment of communication satellite systems. The model describes the economics of the space system throughout the lifetime of the satellite. The expected state-of-the-art status of communications satellite systems and operations beginning service in 1995 were assessed and described. New or enhanced space-based activities and associated satellite system designs that have the potential to achieve future communications satellite operations in geostationary orbit with improved economic performance were postulated and defined. Three scenarios using combinations of space-based activities were analyzed: a spin stabilized satellite, a three axis satellite, and assembly at the Space Station and GEO servicing. Functional and technical requirements placed on the Space Station by the scenarios were detailed. Requirements on the satellite were also listed.

  19. 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…

  20. Communication receivers for satellites - A review

    NASA Astrophysics Data System (ADS)

    Goldberg, H. B.; Dhillon, S. S.

    1984-12-01

    This paper reports the development of all solid-state low-noise wideband receivers for use in communication and direct-broadcast satellites operating in the 5.9- to 6.4-GHz, 14.0- to 14.5-GHz, and 17.3- to 17.8-GHz uplink frequency bands. The receivers provide low-noise and spurious free down conversion of the uplink frequency bands to the downlink frequency bands of 3.7 to 4.2 GHz, 11.7 to 12.2 GHz, and 12.2 to 12.7 GHz, respectively, with excellent frequency stability. The receivers incorporate state-of-the-art GaAs FET devices and microwave integrated-circuit technologies. Details of the design and measured performance of receivers are given.

  1. 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.

  2. Solid-state amplifiers for satellite communications

    NASA Astrophysics Data System (ADS)

    Masse, D.; Harper, R.

    At frequencies greater than 20 GHz, satellite communications transmitters require only moderate power outputs due to higher-gain antennas. Broadband helix TWT capabilities can be increased to 80 W at 44 GHz by using diamond helix supports; such a tube is being developed. IMPATT diodes are becoming the leading contenders for medium power amplification. Silicon, GaAs and InP devices are competing for use at EHF. A comparison between their respective properties is made and state-of-the-art performance is given. Single-diode and multidiode amplifier stages are described and some examples given. Since reliability is of primary importance for this application, some preliminary data supporting the MTTF predictions are presented.

  3. 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.

  4. Satellite Communications Technology Database. Part 2

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The Satellite Communications Technology Database is a compilation of data on state-of-the-art Ka-band technologies current as of January 2000. Most U.S. organizations have not published much of their Ka-band technology data, and so the great majority of this data is drawn largely from Japanese, European, and Canadian publications and Web sites. The data covers antennas, high power amplifiers, low noise amplifiers, MMIC devices, microwave/IF switch matrices, SAW devices, ASIC devices, power and data storage. The data herein is raw, and is often presented simply as the download of a table or figure from a site, showing specified technical characteristics, with no further explanation.

  5. 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.

  6. Geostationary payload concepts for personal satellite communications

    NASA Technical Reports Server (NTRS)

    Benedicto, J.; Rinous, P.; Roberts, I.; Roederer, A.; Stojkovic, I.

    1993-01-01

    This paper reviews candidate satellite payload architectures for systems providing world-wide communication services to mobile users equipped with hand-held terminals based on large geostationary satellites. There are a number of problems related to the payload architecture, on-board routing and beamforming, and the design of the S-band Tx and L-band Rx antenna and front ends. A number of solutions are outlined, based on trade-offs with respect to the most significant performance parameters such as capacity, G/T, flexibility of routing traffic to beams and re-configuration of the spot-beam coverage, and payload mass and power. Candidate antenna and front-end configurations were studied, in particular direct radiating arrays, arrays magnified by a reflector and active focused reflectors with overlapping feed clusters for both transmit (multimax) and receive (beam synthesis). Regarding the on-board routing and beamforming sub-systems, analog techniques based on banks of SAW filters, FET or CMOS switches and cross-bar fixed and variable beamforming are compared with a hybrid analog/digital approach based on Chirp Fourier Transform (CFT) demultiplexer combined with digital beamforming or a fully digital processor implementation, also based on CFT demultiplexing.

  7. The Communications Satellite as Educational Tool.

    ERIC Educational Resources Information Center

    Long, Peter

    1982-01-01

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

  8. The role of satellite communications in the future DCS

    NASA Astrophysics Data System (ADS)

    McKee, W. P., Jr.

    The Defense Communications System (DCS) has the function to provide strategic telecommunications for the U.S. Department of Defense (DOD). In addition, the DCS supports also other U.S. Government communications requirements, such as those of the Department of State. The DCS makes use of military and commercial satellite communications, and of terrestrial transmission media. The role of satellite communications (Satcom) in the current DCS is considered. Military and commercial Satcom used by the DCS employ geostationary satellites in synchronous orbit, generally for continuous point-to-point communications. As a result of recent studies, it was recommended that the DCS adopt the 'mix of media' philosophy to increase its survivability. One of the media which will receive continually expanded employment will be satellite communications. Attention is given to requirements for military communications, and the effectiveness of Satcom. It is concluded that Satcom, which is important in the DCS today, will become even more important in the future.

  9. 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…

  10. 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…

  11. 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.

  12. Flexible satellite communications systems simulator standard device groups

    NASA Astrophysics Data System (ADS)

    Brown, D. W.; Burgess, J. L.

    1986-12-01

    This document contains the designs of the standard device groups (SDG) prepared for the Flexible Satellite Communications Systems Simulation (FSCSS). It contains updates to SDGs prepared for earlier versions of FSCSS and new SDG's prepared for version 4.0. FSCSS is a time domain simulation for accurately determining performance of satellite communications system principally in terms of bit error rate. SDGs are models of earth terminals, satellites and modems from the inventory of the Deense Satellite Communications System (DSCS). These ready-made SATCOM components ease the burden of a FSCSS user setting up large DSCS Systems within FSCSS.

  13. 14/12-GHz-band satellite communication services

    NASA Astrophysics Data System (ADS)

    Hayashi, Kunihiro; Nagaki, Kiyoaki; Mori, Yasuo

    1990-01-01

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

  14. Signalling characteristics in satellite-aided land mobile communications

    NASA Technical Reports Server (NTRS)

    Anderson, R. E.

    1982-01-01

    The feasibility of land mobile radio communications has been demonstrated by a large number of experiments with NASA's ATS satellites. Significant differences in the propagation characteristics of satellite and terrestrial mobile signal paths were observed in the experiments. Terrestrial paths are best in cities where they can provide frequency reuse and assure communication by bouncing signals around obstructions. Satellites may be best in thinly populated areas because they eliminate the need for many tower mounted relays. The satellite paths do not have the severe Rayleigh fading that limits the range and signal quality of terrestrial paths if the satellite is above approximately ten degrees elevation, a value easily achieved for the United States. The experiments verified that high quality voice communications and other functions, such as data transmission and vehicle position surveillance, are easily accomplished through geostationary satellites with vehicle transmitter power and antenna gain no different than those of terrestrial mobile communications.

  15. Signalling characteristics in satellite-aided land mobile communications

    NASA Astrophysics Data System (ADS)

    Anderson, R. E.

    The feasibility of land mobile radio communications has been demonstrated by a large number of experiments with NASA's ATS satellites. Significant differences in the propagation characteristics of satellite and terrestrial mobile signal paths were observed in the experiments. Terrestrial paths are best in cities where they can provide frequency reuse and assure communication by bouncing signals around obstructions. Satellites may be best in thinly populated areas because they eliminate the need for many tower mounted relays. The satellite paths do not have the severe Rayleigh fading that limits the range and signal quality of terrestrial paths if the satellite is above approximately ten degrees elevation, a value easily achieved for the United States. The experiments verified that high quality voice communications and other functions, such as data transmission and vehicle position surveillance, are easily accomplished through geostationary satellites with vehicle transmitter power and antenna gain no different than those of terrestrial mobile communications.

  16. 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.

  17. 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.

  18. Modulation and coding used by a major satellite communications company

    NASA Technical Reports Server (NTRS)

    Renshaw, K. H.

    1992-01-01

    Hughes Communications Inc., is a major satellite communications company providing or planning to provide the full spectrum of services available on satellites. All of the current services use conventional modulation and coding techniques that were well known a decade or longer ago. However, the future mobile satellite service will use significantly more advanced techniques. JPL, under NASA sponsorship, has pioneered many of the techniques that will be used.

  19. Japanese first optical interorbit communications engineering satellite (OICETS)

    NASA Astrophysics Data System (ADS)

    Yamamoto, Akio; Hori, Toshihiro; Shimizu, Takafumi; Nakagawa, Keizo

    1994-09-01

    The National Space Development Agency of Japan (NASDA) plans to conduct an optical inter-orbit ling experiment in cooperation with the European Space Agency (ESA). ESA will launch the ARTEMIS geostationary satellite equipped with the SILEX optical terminal. NASDA will launch the Optical Inter-orbit Communications Engineering Test Satellite (OICETS) equipped with the LUCE optical inter-orbit communications equipment into low earth orbit. The link experiment will be conducted between these satellites with associated ground equipment in Europe and Japan.

  20. Satellite communications for the Pacific islands. Second year report

    NASA Technical Reports Server (NTRS)

    Young, E.; Hurd, J. N.

    1982-01-01

    Requirements, options and costs for use of communications satellites in underserved areas of the Pacific Basin are described with emphasis on extended utilization of INTELSAT. The economic structures within and among Pacific Basin entities are examined, particularly the relationship between the growth of regional trade and telecommunications potential for the region. Suitable satellite services are recommended and the financial implications for extended utilization of communications satellites in the Pacific Basin are considered.

  1. 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.

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

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

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

  3. Suitability of ANSI standards for quantifying communication satellite system performance

    NASA Technical Reports Server (NTRS)

    Cass, Robert D.

    1988-01-01

    A study on the application of American National Standards X3.102 and X3.141 to various classes of communication satellite systems from the simple analog bent-pipe to NASA's Advanced Communications Technology Satellite (ACTS) is discussed. These standards are proposed as means for quantifying the end-to-end communication system performance of communication satellite systems. An introductory overview of the two standards are given followed by a review of the characteristics, applications, and advantages of using X3.102 and X3.141 to quantify with a description of the application of these standards to ACTS.

  4. 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.

  5. 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.

  6. Cockpit weather graphics using mobile satellite communications

    NASA Technical Reports Server (NTRS)

    Seth, Shashi

    1993-01-01

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

  7. Engineering calculations for communications satellite systems planning

    NASA Technical Reports Server (NTRS)

    Reilly, Charles H.; Walton, Eric K.; Kohnhorst, Paul

    1987-01-01

    A procedure is described that was used to calculate minimum required satellite separations based on total link carrier to interference requirements. Also summarized are recent results with a switching algorithm for satellite synthesis problems. Analytic solution value bounds for two of the satellite synthesis models studied are described. Preliminary results from an empirical study of alternate mixed integer programming models for satellite synthesis are presented. Research plans for the near future are discussed.

  8. 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.

  9. 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-δ) constellation with three orbit planes. In access layer, each plane has two satellites, and the constellation is stably. The satellite constellation presented for space laser network can meet the demand of coverage in the middle and low latitude by a few satellites. Also several terminal device models such as the space laser transmitter, receiver, protocol layer module and optical antenna have been designed according to the inter-satellite links in different orbits t from GEO to LEO or GEO to ground. The influence to network of different transmitting throughput, receiving throughput, network protocol and average time delay are simulated. Simulation results of network coverage, connectivity and traffic load performance in different scenes show that the satellite laser network presented by the paper can be fit for high-speed satellite communications. Such analysis can provide effective reference for the research of satellite laser networking and communication protocol.

  10. 622 Mbps High-speed satellite communication system for WINDS

    NASA Astrophysics Data System (ADS)

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

    2006-07-01

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

  11. Ultra high frequency follow-on communications satellite system

    NASA Astrophysics Data System (ADS)

    Hassien, Michael J.

    1992-03-01

    The existing constellation of UHF communications satellites (LEASAT and FLTSAT) provide key command and control links for mobile forces of the DoD and other government agencies. The UHF Follow-On satellite program will provide for a new generation of communications satellites to replace the existing ones as they reach the end of their life cycle beginning in 1992. Continued coverage is required for both peacetime and crisis environments, and must be maintained indefinitely. An eight-satellite UFO constellation (two per coverage area) will replenish the existing FLTSATCOM constellation.

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

    NASA Technical Reports Server (NTRS)

    Bartholome, P.; Rogard, R.

    1988-01-01

    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.

  13. Power beaming to communication satellites in GEO

    SciTech Connect

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

    1992-12-31

    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/m{sup 2} (four times conventional).

  14. 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.

  15. Augmentation of a commercial satellite system for military communications

    NASA Astrophysics Data System (ADS)

    Butte, Eric G.; Thorburn, Michael

    2005-06-01

    Future U.S. MILSATCOM will rely on a complex satellite design to implement the TSAT satellite system that was developed on the Transformational Communication Architecture program. TSAT will deliver secured IP based, on-demand communication system to meet the needs of the military and the warfighter and will demand a very large satellite system, program, and an anticipated lengthy deployment time. An alternate system is proposed that can give IP based communications in a significantly shorter time frame. A constellation of commercial-like satellites, with transponded Ka-, Ku- and X-band, would nicely complement the MILSATCOM fleet. The services provided by these satellites would enable widespread communications services such as IP to the theatre, augmenting the DSCS, Wideband Gapfiller, and protected communications systems of MILSTAR and Advanced EHF. The capacity provided by the dedicated commercial satellites would help provide the capacity demanded by the warfighter as MILSATCOM transitions from today's technology to the TSAT system of tomorrow's Transformational Communications Architecture. This paper will discuss the satellite concept design and how it can augment the MILSATCOM fleet and show a more flexible approach of bandwidth management to support fixed and COTM terminals.

  16. Orbital design strategy for domestic communication satellite systems.

    NASA Technical Reports Server (NTRS)

    Ramji, S.; Sawitz, P.

    1973-01-01

    Review of some of the considerations pertinent to efficient orbit utilization in the design of domestic communications satellite systems. A strategy is developed to efficiently locate a heterogeneous system of satellites within the available arc and provide room for future growth. A practical design is illustrated, using a computer simulation model, for the placement of 25 satellites within 73% of the available arc employing frequency and polarization coordination techniques. A number of widely variable factors that influence satellite spacing are examined. These factors include such critical system elements as telephony and television interference noise limits, frequency plan coordination, polarization plan coordination, ground antenna diameter, signal protection ratio, and satellite station keeping.

  17. 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.

  18. 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.

  19. The Syncom IV-4 communications satellite deployed from payload bay

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The Syncom IV-4 communications satellite is deployed from the payload bay of the Shuttle Discovery in a frisbee fashion. A portion of the cloudy surface of the earth can be seen to the left of the frame.

  20. Live Satellite Communications... An Exciting Teaching Aid

    ERIC Educational Resources Information Center

    Journal of Aerospace Education, 1976

    1976-01-01

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

  1. 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.

  2. Communication satellites for STS-5 being readied for loading

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Two commercial communication satellites scheduled for flight on STS-5 are pictured as they are being readied for loading into a special canister that will transport them to the launch pad. Telsat Canada's Anik C-3 (at bottom) is seen in its blanket covered cradle assemble. Satellite Business System's SBS-3 is at top. This photo was taken inside the vertical processing facility (VPF).

  3. Second INTELSAT IV-A communications satellite set for launch

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The scheduled launching of INTELSAT 4-A is announced. It is a commercial communications satellite to be launched aboard an Atlas/Centaur Launch Vehicle from the Kennedy Space Center, Fla. The satellite has the capability of carrying approximately 6250 two-way telephone conversations.

  4. 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…

  5. The optical communication link outage probability in satellite formation flying

    NASA Astrophysics Data System (ADS)

    Arnon, Shlomi; Gill, Eberhard

    2014-02-01

    In recent years, several space systems consisting of multiple satellites flying in close formation have been proposed for various purposes such as interferometric synthetic aperture radar measurement (TerraSAR-X and the TanDEM-X), detecting extra-solar earth-like planets (Terrestrial Planet Finder-TPF and Darwin), and demonstrating distributed space systems (DARPA F6 project). Another important purpose, which is the concern of this paper, is for improving radio frequency communication to mobile terrestrial and maritime subscribers. In this case, radio frequency signals from several satellites coherently combine such that the received/transmit signal strength is increased proportionally with the number of satellites in the formation. This increase in signal strength allows to enhance the communication data rate and/or to reduce energy consumption and the antenna size of terrestrial mobile users' equipment. However, a coherent combination of signals without aligning the phases of the individual communication signals interrupts the communication and outage link between the satellites and the user. The accuracy of the phase estimation is a function of the inter-satellite laser ranging system performance. This paper derives an outage probability model of a coherent combination communication system as a function of the pointing vibration and jitter statistics of an inter-satellite laser ranging system tool. The coherent combination probability model, which could be used to improve the communication to mobile subscribers in air, sea and ground is the main importance of this work.

  6. Engineering calculations for communications satellite systems planning

    NASA Technical Reports Server (NTRS)

    Levis, C. A.; Martin, C. H.; Reilly, C. H.; Gonsalvez, D. J.; Yamaura, Y.

    1985-01-01

    An extended gradient search code for broadcasting satellite service (BSS) spectrum/orbit assignment synthesis is discussed. Progress is also reported on both single-entry and full synthesis computational aids for fixed satellite service (FSS) spectrum/orbit assignment purposes.

  7. 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…

  8. 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…

  9. 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…

  10. Communication satellite technology: State of the art and development opportunities

    NASA Technical Reports Server (NTRS)

    Woodford, J. B. (Compiler)

    1978-01-01

    Opportunities in communication satellite technology are identified and defined. Factors that tend to limit the ready availability of satellite communication to an increasingly wide group of users are evaluated. Current primary limitations on this wide utilization are the availability of frequency and/or synchronous equatorial satellite positions and the cost of individual user Earth terminals. The former could be ameliorated through the reuse of frequencies, the use of higher frequency bands, and the reduction of antenna side lobes. The latter limitation requires innovative hardware, design, careful system design, and large scale production.

  11. Secure UHF satellite communications for the 1980's

    NASA Astrophysics Data System (ADS)

    Brauer, F. M.

    It is expected that UHF satellite communications will remain the most common medium for small military platforms' secure communications links. Routine, high volume military data will in this case be handled by commercially leased satellites, and the most sensitive information, some of which will be carried by UHF, being handled by the Milstar satellite. Attention is presently given to the means by which the prospective saturation of UHF links as many more thousands of terminals come on line can be efficiently managed through better use of both channel bandwidth and time.

  12. Land vehicle antennas for satellite mobile communications

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

  13. 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.

  14. 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.

  15. 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.

  16. Technology requirements for communication satellites in the 1980's

    NASA Technical Reports Server (NTRS)

    Burtt, J. E.; Moe, C. R.; Elms, R. V.; Delateur, L. A.; Sedlacek, W. C.; Younger, G. G.

    1973-01-01

    The key technology requirements are defined for meeting the forecasted demands for communication satellite services in the 1985 to 1995 time frame. Evaluation is made of needs for services and technical and functional requirements for providing services. The future growth capabilities of the terrestrial telephone network, cable television, and satellite networks are forecasted. The impact of spacecraft technology and booster performance and costs upon communication satellite costs are analyzed. Systems analysis techniques are used to determine functional requirements and the sensitivities of technology improvements for reducing the costs of meeting requirements. Recommended development plans and funding levels are presented, as well as the possible cost saving for communications satellites in the post 1985 era.

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

    NASA Technical Reports Server (NTRS)

    Palmer, L. C.; Stern, A.; Sohn, P. Y.

    1991-01-01

    The feasibility of portable communications terminals that can provide 4.8-kbps voice communications to a hub station via a Ka-band geosynchronous satellite was investigated. Tradeoffs are examined so that the combined system of the 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 is described using a spacecraft with approximately 140 spot beams that cover CONUS with 5-watt power amplifiers in each beam. 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/sec. An experiment is recommended using the Advanced Communications Technology Satellite (ACTS) to demonstrate some of the features of the portable terminal concept.

  18. 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.

  19. Future large broadband switched satellite communications networks

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

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

  20. 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

  1. 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.

  2. FD/DAMA Scheme For Mobile/Satellite Communications

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    Integrated-Adaptive Mobile Access Protocol (I-AMAP) proposed to allocate communication channels to subscribers in first-generation MSAT-X mobile/satellite communication network. Based on concept of frequency-division/demand-assigned multiple access (FD/DAMA) where partition of available spectrum adapted to subscribers' demands for service. Requests processed, and competing requests resolved according to channel-access protocol, or free-access tree algorithm described in "Connection Protocol for Mobile/Satellite Communications" (NPO-17735). Assigned spectrum utilized efficiently.

  3. Satellite-aided mobile communications, experiments, applications and prospects

    NASA Technical Reports Server (NTRS)

    Anderson, R. E.; Frey, R. L.; Lewis, J. R.; Milton, R. T.

    1980-01-01

    NASA's ATS-series of satellites were used in a series of communications and position fixing experiments with automotive vehicles, ships and aircraft. Applications of the communications were demonstrated and evaluated for public services including law enforcement, search and rescue, and medical emergency, and for commercial uses in the land and maritime transportation industries. The technical success of the experiments and the demonstrated potential value of the communications prompted a study that concluded an operational satellite-aided system would be a valuable augmentation of planned trunking or cellular type terrestrial mobile radio telephone systems.

  4. 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.

  5. Secure satellite communication using multi-photon tolerant quantum communication protocol

    NASA Astrophysics Data System (ADS)

    Darunkar, Bhagyashri; Punekar, Nikhil; Verma, Pramode K.

    2015-09-01

    This paper proposes and analyzes the potential of a multi-photon tolerant quantum communication protocol to secure satellite communication. For securing satellite communication, quantum cryptography is the only known unconditionally secure method. A number of recent experiments have shown feasibility of satellite-aided global quantum key distribution (QKD) using different methods such as: Use of entangled photon pairs, decoy state methods, and entanglement swapping. The use of single photon in these methods restricts the distance and speed over which quantum cryptography can be applied. Contemporary quantum cryptography protocols like the BB84 and its variants suffer from the limitation of reaching the distances of only Low Earth Orbit (LEO) at the data rates of few kilobits per second. This makes it impossible to develop a general satellite-based secure global communication network using the existing protocols. The method proposed in this paper allows secure communication at the heights of the Medium Earth Orbit (MEO) and Geosynchronous Earth Orbit (GEO) satellites. The benefits of the proposed method are two-fold: First it enables the realization of a secure global communication network based on satellites and second it provides unconditional security for satellite networks at GEO heights. The multi-photon approach discussed in this paper ameliorates the distance and speed issues associated with quantum cryptography through the use of contemporary laser communication (lasercom) devices. This approach can be seen as a step ahead towards global quantum communication.

  6. 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.

  7. 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.

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

    NASA Technical Reports Server (NTRS)

    Namkoong, D.

    1984-01-01

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

  9. Advances in MMIC technology for communications satellites

    NASA Astrophysics Data System (ADS)

    Leonard, Regis F.

    1992-03-01

    This paper discusses NASA Lewis Research Center's program for development of monolithic microwave integrated circuits (MMIC) for application in space communications. Emphasis will be on the improved performance in power amplifiers and low noise receivers which has been made possible by the development of new semiconductor materials and devices. Possible applications of high temperature superconductivity for space communications will also be presented.

  10. Development of a mobile satellite communication unit

    NASA Technical Reports Server (NTRS)

    Suzuki, Ryutaro; Ikegami, Tetsushi; Hamamoto, Naokazu; Taguchi, Tetsu; Endo, Nobuhiro; Yamamoto, Osamu; Ichiyoshi, Osamu

    1988-01-01

    A compact 210(W) x 280(H) x 330(D) mm mobile terminal capable of transmitting voice and data through L-band mobile satellites is described. The Voice Codec can convert an analog voice to or from digital codes at rates of 9.6, 8 and 4.8 kb/s by an MPC algorithm. The terminal functions with a single 12 V power supplied vehicle battery. The equipment can operate at any L-band frequency allocated for mobile uses in a full duplex mode and will soon be put into a field test via Japans's ETS-V satellite.

  11. Effect of Ionosphere on Geostationary Communication Satellite Signals

    NASA Astrophysics Data System (ADS)

    Erdem, Esra; Arikan, Feza; Gulgonul, Senol

    2016-07-01

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

  12. RF switch positioner for communications satellite network

    NASA Technical Reports Server (NTRS)

    Storaasli, A. G.; Griesser, H. P.; Grant, R. W.

    1986-01-01

    The RF switch positioner is a simple, lightweight, redundant positioning mechanism used to reconfigure the antenna beam on the INTELSAT VI satellite. It simultaneously rotates approximately 100 squareax waveguide switches through a full 360 deg. The RF switch positioner has been space qualified and has performed to expectations in conjunction with the feed networks in range testing.

  13. Satellite quantum communication towards GEO distances

    NASA Astrophysics Data System (ADS)

    Vallone, Giuseppe; Dequal, Daniele; Tomasin, M.; Schiavon, M.; Vedovato, F.; Bacco, Davide; Gaiarin, Simone; Bianco, Giuseppe; Luceri, Vincenza; Villoresi, Paolo

    2016-04-01

    We report on several experiments of single photon transmission from space to ground realized at the Matera Laser Ranging Observatory (MLRO) of the Italian Space Agency in Matera (Italy). We simulated a source of coherent pulses attenuated to the single photon level by exploiting laser ranging satellites equipped with corner-cube retroreflectors (CCRs). By such technique we report QC with qubits encoded in polarization from low-Earth-orbit (LEO) at distance up to 2500km from the ground station, achieving a low quantum bit error ratio (QBER) for different satellites. The same technique is exploited to demonstrate single photon exchange with a medium-Earth-orbit (MEO) satellite, Lageos-2 at more than 7000 km of distance from the MLRO station. In both experiments the temporal jitter of the received counts is of the order of 1.2ns FWHM due to the intrinsic jitter of the single photon detectors. In order to improve the discrimination of signal from the background and reaching distances corresponding to GEO satellites, we improved the detection scheme by using fast single photon detectors with 40 ps FWHM jitter. We report improved single photon detection jitter from Beacon-C and Ajisai, obtaining 340 ps FWHM in the best case.

  14. 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.

  15. Spread spectrum mobile communication experiment using ETS-V satellite

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

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

  16. Satellite communications experiment for the Ontario air ambulance service

    NASA Astrophysics Data System (ADS)

    Butterworth, John S.

    1988-05-01

    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. 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.

  18. Program on application of communications satellites to educational development

    NASA Technical Reports Server (NTRS)

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

    1971-01-01

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

  19. Olympus: The communications satellite and its uses. An introduction

    NASA Astrophysics Data System (ADS)

    Longdon, Norman

    1991-01-01

    Olympus is the largest civil communications satellite ever launched. It is owned and operated by the European Space Agency (ESA) and is in a geostationary orbit at longitude 19 degrees W. Olympus was specifically designed to test the technologies needed for future satellite applications and services. However, capacity is also available to demonstrate new services via satellite such as tele-education and business communications. All the payloads are powerful enough to be used with very small earth stations. Olympus carries four quite distinct payloads, each with its own steerable antennas. The payloads are the (Direct) Broadcast Payload, the Specialized Services Payload, the 30/20 GHz Communications Payload, and the Propagation Payload. Various aspects of the services Olympus provides, how to use these services, and details on the payloads are presented.

  20. Computer-aided communication satellite system analysis and optimization

    NASA Technical Reports Server (NTRS)

    Stagl, T. W.; Morgan, N. H.; Morley, R. E.; Singh, J. P.

    1973-01-01

    The capabilities and limitations of the various published computer programs for fixed/broadcast communication satellite system synthesis and optimization are discussed. A satellite Telecommunication analysis and Modeling Program (STAMP) for costing and sensitivity analysis work in application of communication satellites to educational development is given. The modifications made to STAMP include: extension of the six beam capability to eight; addition of generation of multiple beams from a single reflector system with an array of feeds; an improved system costing to reflect the time value of money, growth in earth terminal population with time, and to account for various measures of system reliability; inclusion of a model for scintillation at microwave frequencies in the communication link loss model; and, an updated technological environment.

  1. Deployment of the Morelos-D communications satellite for Mexico

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The Morelos-D communications satellite is deployed for Mexico from the cargo bay of the Shuttle Atlantis during the STS 61-B mission. Behind it can be seen the closed cradle of the RCA Satcom satellite that was also deployed in this mission. At the front of the photo is the Assembly of Structures - Assembly Concept for Construction of Erectable Space Structures (EASE/ACCESS) hardware.

  2. 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.

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

    NASA Technical Reports Server (NTRS)

    Meyer, Thomas R.

    1990-01-01

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

  4. 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.

  5. Von Karman Lecture - The rocky road to communication satellites

    NASA Astrophysics Data System (ADS)

    Wheelon, A. D.

    1986-01-01

    The history of communications satellites traced in terms of the confluence of the forces of technology, economics and public policy is discussed. The idea of placing communications satellites in GEO was put forward by a science fiction writer in 1945. Syncom II was launched, with a TWT amplifier, into GEO in 1963. Telstar provided the first live transoceanic broadcasts in 1962, just before Comsat was chartered. Early Bird proved that telephony links through GEO satellites was feasible. The follow-up, Intelsat II, was partially spurred by the Apollo program with its worldwide communications demands. Intelsat began with three spacecraft that formed the foundation for the present system. The Intelsat monopoly on worldwide common carrier links is being challenged by ground-based links and entrepreneurial activities spurred by deregulation. An open-skies policy formulated in the U.S. in the late 1960s has led to the launch of various domestic satellite systems with narrow beam transmissions using C- and Ku-band frequencies. Satellite access costs have fallen because of the capabilities of renting or selling individual transponders. Mobile communications systems may soon be served through a joint U.S.-Canada project. Finally, the WARC 1977 set the ground rules for DBS television service, which is in the process of being implemented, mainly by cable operators.

  6. The Globalstar mobile satellite system for worldwide personal communications

    NASA Technical Reports Server (NTRS)

    Wiedeman, Robert A.; Viterbi, Andrew J.

    1993-01-01

    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.

  7. 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.

  8. 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.

  9. 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.

  10. High speed laser communication network for satellite systems

    NASA Astrophysics Data System (ADS)

    Panahi, Allen; Kazemi, Alex A.

    2011-06-01

    Using optical links in space and building high speed laser communications network has proven to be an extremely complicated task and many such schemes were tried without success in the past. However, in the last few years, there has been impressive progress made to bring the concept to fruition in civilian and government-non classified projects. In this paper we will focus on the requirements of the space-based lasers and optics used for beam forming, as well as receiver antenna gain and detectors used in free space communications. High data rate, small antenna size, narrow beam divergence, and a narrow field of view are characteristics of laser communications that offer a number of potential advantages for system design. Space-based optical communications using satellites in low earth orbit (LEO) and Geo-synchronous orbits (GEO) hold great promise for the proposed Internet in the Sky network of the future. Also discussed are the critical parameters in the transmitter, channel, receiver, and link budget that are employed in successful inter-satellite communications system. We cover that Laser Communications offer a viable alternative to established RF communications for inter-satellite links and other applications where high performance links are a necessity.

  11. 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.

  12. 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).

  13. Modeling of NASA's 30/20 GHz satellite communications system

    NASA Technical Reports Server (NTRS)

    Kwatra, S. C.; Maples, B. W.; Stevens, G. A.

    1984-01-01

    NASA is in the process of developing technology for a 30/20 GHz satellite communications link. Currently hardware is being assembled for a test transponder. A simulation package is being developed to study the link performance in the presence of interference and noise. This requires developing models for the components of the system. This paper describes techniques used to model the components for which data is available. Results of experiments performed using these models are described. A brief overview of NASA's 30/20 GHz communications satellite program is also included.

  14. Design and evaluation of control systems for large communications satellites

    NASA Technical Reports Server (NTRS)

    Steiber, M. E.

    1985-01-01

    Control techniques for future large flexible spacecraft are developed. Control design and analysis are supported by a comprehensive CAD system. The proposed operational mobile communications satellite (OMSAT) featuring a 44 m offset fed antenna is used as target application. Requirements for satellite attitude control and communications beam pointing are defined. The following control methods are applied to the system: standard linear optimal regulator (LOR) with Luenberger observer, LOR/observer with selective spill-over suppression, frequency shaped LOR, LOR with closed-loop order reduction by cost decoupling, and robust servomechanism.

  15. College curriculum-sharing via CTS. [Communications Technology Satellite

    NASA Technical Reports Server (NTRS)

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

    1975-01-01

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

  16. Experimental millimeter-wave personal satellite communications system

    NASA Technical Reports Server (NTRS)

    Suzuki, Yoshiaki; Kimura, Shigeru; Shimada, Masaaki; Tanaka, Masato; Takahashi, Yasuhiro

    1991-01-01

    Communications Research Laboratory (CRL) has investigated an advanced millimeter (mm)-wave satellite communications system for personal use. Experiments in mm-wave personal satellite communication are to be conducted for 3 years using Japan's Engineering Test Satellite VI (ETS-VI). This paper describes an experimental mm-wave (43/38 GHz) personal satellite communication system, including an onboard transponder and an earth terminal. The on-board transponder is almost completed, and the ground experiment system is still in the design stage. The transponder employs advanced mm-wave solid state technology. It uses 38 GHz high power solid state amplifiers to accelerate the development of mm-wave solid state devices which are indispensable to personal earth terminals. The transponder consists of a 43 GHz receiver with a built-in low noise amplifier, an IF filter section with very narrow bandwidth to improve the carrier-to-noise power ratio of the weak personal communication signal, and two high power amplifiers using newly developed high power Gallium Arsenide (GaAs) metal-semiconductor field effect transistors (MESFETs).

  17. Experimental millimeter-wave personal satellite communications system

    NASA Astrophysics Data System (ADS)

    Suzuki, Yoshiaki; Kimura, Shigeru; Shimada, Masaaki; Tanaka, Masato; Takahashi, Yasuhiro

    1991-09-01

    Communications Research Laboratory (CRL) has investigated an advanced millimeter (mm)-wave satellite communications system for personal use. Experiments in mm-wave personal satellite communication are to be conducted for 3 years using Japan's Engineering Test Satellite VI (ETS-VI). This paper describes an experimental mm-wave (43/38 GHz) personal satellite communication system, including an onboard transponder and an earth terminal. The on-board transponder is almost completed, and the ground experiment system is still in the design stage. The transponder employs advanced mm-wave solid state technology. It uses 38 GHz high power solid state amplifiers to accelerate the development of mm-wave solid state devices which are indispensable to personal earth terminals. The transponder consists of a 43 GHz receiver with a built-in low noise amplifier, an IF filter section with very narrow bandwidth to improve the carrier-to-noise power ratio of the weak personal communication signal, and two high power amplifiers using newly developed high power Gallium Arsenide (GaAs) metal-semiconductor field effect transistors (MESFETs).

  18. The application of mobile satellite services to emergency response communications

    NASA Technical Reports Server (NTRS)

    Freibaum, J.

    1980-01-01

    The application of an integrated satellite/terrestrial emergency response communications system in disaster relief operations is discussed. Large area coverage communications capability, full-time availability, a high degree of mobility, plus reliability, are pointed out as criteria for an effective emergency communications system. Response time is seen as a major factor determining the possible survival and/or protection of property. These criteria, can not be met by existing communications systems and complete blackouts were experienced during the past decades caused by either interruption or destruction of existing power lines, and overload or inadequacy of remaining lines. Several emergency cases, caused by either hurricanes, tornados, or floods, during which communication via satellite was instrumental to inform rescue and relief teams, are described in detail. Seismic Risk Maps and charts of Major Tectonic Plates Earthquake Epicenters are given, and it is noted that, 35 percent of the U.S. population is living in critical areas. National and international agreements for the implementation of a satellite-aided global Search and Rescue Program is mentioned. Technological and economic breakthroughs are still needed in large multibeam antennas, switching circuits, and low cost mobile ground terminals. A pending plan of NASA to initiate a multiservice program in 1982/83, with a Land Mobile Satellite capability operating in the 806 - 890 MHz band as a major element, may help to accelerate the needed breakthroughs.

  19. Some proposed experiments with the Communications Technology Satellite

    NASA Technical Reports Server (NTRS)

    Porter, A.

    1975-01-01

    The satellite (CTS) is tentatively scheduled to be launched in January 1976. It will be available for educational and societal experimentation early in 1977. This paper will outline some of the educational experiments involving the CTS. The major object of the experiments is to assess the communications and educational implications of the CTS in northern Ontario; the existing communications facilities for this region of approximately 725,000 sq km (inhabited largely by native people) are extremely limited. It is expected to assess the extent to which: (1) a satellite communications system might resolve the communications deficiency, (2) the native people will use the experimental facility, and (3) health and general educational programs, especially utilizing the interactive mode, will be viable.

  20. 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.).

  1. Local oscillator selection for digital satellite communications

    NASA Astrophysics Data System (ADS)

    Kumar, Surinder

    1988-07-01

    The paper presents a comparative study of different local oscillator (LO) designs and their suitability for digital communications. Based on the system budget for performance degradation due to carrier phase noise, a specification for the LO phase noise is derived. Consideration is given to the following types of LO subsystems: mechanical cavity, VTO-PLO, DRO-PLO, and multiplier chain.

  2. 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.

  3. Engineering calculations for communications satellite systems planning

    NASA Technical Reports Server (NTRS)

    Reilly, C. H.; Levis, C. A.; Buyukdura, O. M.; Mount-Campbell, C. A.

    1986-01-01

    Observed solution times were analyzed for the extended gradient and cyclic coordinate search procedures. The times used in the analysis come from computer runs made during a previously-reported experiment conducted to assess the quality of the solutions to a BSS synthesis problem found by the two search methods. The results of a second experiment with a Fixed Satellite Service (FSS) test problem are also presented. Computational results are summarized for mixed integer programming approaches for solving FSS synthesis problems. A promising heuristic algorithm is described. A synthesis model is discussed for orbital arc allotment optimization. Research plans for the near future are also presented.

  4. Secure satellite communications in the ISDN

    NASA Astrophysics Data System (ADS)

    de Cristofaro, R.; Bratcher, B. A.

    The single channel per carrier (SCPC) earth station equipment using continuously variable slope delta modulation voice encoding and phase shift keying carrier modulation is examined. The satellite earth station for SCPC consists of: antenna, high power amplifier, low noise amplifier, RF up-converter and down-converter, and the SCPC common equipment and channel unit. The functions and operations of the common equipment and channel unit of the SCPC are described. The data transmission security is achieved using full duplex digital encryption; the crypto synchronizing sequence format is discussed.

  5. 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.

  6. 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.

  7. R. F. testing of the third generation defense communication satellite

    NASA Technical Reports Server (NTRS)

    Sargent, J.; Massaro, M.

    1980-01-01

    The approach taken to test a completed DSCS communications satellite on a system level is described. Areas to be described are measuring RF isolation of separate communications subsystems and a test method which insures that one RF subsystem does not interfere with another. In addition, the method of complying with MIL-STD-1541 in the area of demonstrating safety of electroexplosive devices in an RF field is discussed.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Laser Communications Airborne Testbed: Potential For An Air-To-Satellite Laser Communications Link

    NASA Astrophysics Data System (ADS)

    Feldmann, Robert J.

    1988-05-01

    The Laser Communications Airborne Testbed (LCAT) offers an excellent opportunity for testing of an air-to-satellite laser communications link with the NASA Advanced Communications Technology Satellite (ACTS). The direct detection laser portion of the ACTS is suitable for examining the feasibility of an airborne terminal. Development of an airborne laser communications terminal is not currently part of the ACTS program; however, an air-to-satellite link is of interest. The Air Force performs airborne laser communications experiments to examine the potential usefulness of this technology to future aircraft. Lasers could be used, for example, by future airborne command posts and reconnaissance aircraft to communicate via satellite over long distances and transmit large quantities of data in the fastest way possible from one aircraft to another or to ground sites. Lasers are potentially secure, jam resistant and hard to detect and in this regard increase the survivability of the users. Under a contract awarded by Aeronautical Systems Division's Avionics Laboratory, a C-135E testbed aircraft belonging to ASD's 4950th Test Wing will be modified to create a Laser Communications Airborne Testbed. The contract is for development and fabrication of laser testbed equipment and support of the aircraft modification effort by the Test Wing. The plane to be modified is already in use as a testbed for other satellite communications projects and the LCAT effort will expand those capabilities. This analysis examines the characteristics of an LCAT to ACTS direct detection communications link. The link analysis provides a measure of the feasibility of developing an airborne laser terminal which will interface directly to the LCAT. Through the existence of the LCAT, the potential for development of an air-to-satellite laser communications terminal for the experimentation with the ACTS system is greatly enhanced.

  13. A method to ensure energy security of satellite communication systems

    NASA Astrophysics Data System (ADS)

    Chipiga, A. F.; Senokosova, A. V.

    2009-10-01

    A method is substantiated to ensure energy security for the satellite communication systems (SCS) at a close position of the radio interception receiver. This is done by lowering the carrier frequency down to f 0 = 60…80 MHz and by applying spaced measurements with n ≥ 4 receiving antennas.

  14. Performance of a communication satellite system in simulated RFI

    NASA Technical Reports Server (NTRS)

    Riddle, L. P.

    1981-01-01

    Vulnerability of an advanced communication satellite system to pulsed RFI is examined. Results of an experimental simulation are compared with calculated system degradation. System performance in pulsed RFI is found to be quite good with well-designed ground receiving equipment.

  15. Within compound, looking southeast, Satellite Communications Terminal Building (Building 5771) ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Within compound, looking southeast, Satellite Communications Terminal Building (Building 5771) to left, Gate House (Building 5764) to right of center - Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

  16. 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.

  17. 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.

  18. New Opportunities with the Advanced Communications Technology Satellite (ACTS)

    NASA Technical Reports Server (NTRS)

    Bauer, Robert

    1998-01-01

    Various issues associated with the Advanced Communications Technology Satellite (ACTS) are presented in viewgraph form. Specific topics include: 1) ACTS program review; 2) Spot beam locations; 3) Key ACTS technologies; 4) ACTS accomplishments; 5) Experiments operations; 6) Inclined orbit opportunity, mission and impact; 7) Modifications summary; 8) Experiment opportunity, categories, processes; and 9) Recent and ongoing activity.

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

    NASA Astrophysics Data System (ADS)

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

    2009-03-01

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

  20. Assessment of Commercial Satellite Communications Initiative (CSCI) studies

    NASA Astrophysics Data System (ADS)

    Smith, N.; Kearns, W.; Chapell, P.

    1994-01-01

    This report summarizes the fixed and mobile satellite services (FSS, MSS) as studied by three contractors: COMSAT, Hughes, and Space Systems/LORAL. Each contractor developed a commercial satellite communications initiative (CSCI) architecture based on the requirements provided them from DOD's Integrated Communications Data Base (ICDB). An implementation plan, recommending an acquisition, transition, logistics, and host nation approval plan, was developed according to each contractor's recommended architecture. In addition, this report summarizes the demonstrations conducted by each contractor and the vulnerabilities inherent in using commercial satellites. This summary information is provided as the foundation for the section on the government's assessment and critique of the CSCI study which emphasizes the highlights and remaining uncertainties from this program.

  1. 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.

  2. 20/30 GHz satellite personal communications networks

    NASA Technical Reports Server (NTRS)

    Palmer, L. C.; Stern, A.; Sohn, P. Y.

    1992-01-01

    The feasibility of personal communications networks that can provide 4.8-kbps voice communications between portable terminals and 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 is described using a spacecraft with approximately 140 spot beams that cover CONUS with 5-watt power amplifiers in each beam. Satellite access in both the forward and return directions uses frequency division multiple access/code division multiple access with a chip rate of 2.5 Mchip/sec.

  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. 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.

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

    NASA Technical Reports Server (NTRS)

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

    1978-01-01

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

  6. 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.

  7. Advanced EHF technologies for lightweight augmentation/restoration communications satellites

    NASA Astrophysics Data System (ADS)

    Kolba, Dean P.; Greenberg, William L.; McElroy, David R.; Semprucci, Marilyn D.

    Small EHF satellites can significantly complement the anti-jam service provided by basic EHF MILSATCOM space segments. Mobile/survivable launch vehicles with rapid launch preparations can be utilized to responsively deploy these small satellites into high-altitude elliptical or circular orbits. From such orbits, only a few satellites are needed to provide high-duty-cycle coverage of a critical area. The communications capabilities provided by these EHF payloads can range from (75-2400 bps per channel to 10 Mbps or more per links, depending on the payload configuration. Through the use of EHF waveform standards, these augmentation/restoration satellites will be compatible with existing and planned EHF terminals.

  8. The Advanced Communications Technology Satellite - Performance, Reliability and Lessons Learned

    NASA Technical Reports Server (NTRS)

    Krawczyk, Richard J.; Ignaczak, Louis R.

    2000-01-01

    The Advanced Communications Satellite (ACTS) was conceived and developed in the mid- 1980s as an experimental satellite to demonstrate unproven Ka-band technology, and potential new commercial applications and services. Since launch into geostationary orbit in September 1993. ACTS has accumulated almost seven years of essentially trouble-free operation and met all program objectives. The unique technology, service experiments. and system level demonstrations accomplished by ACTS have been reported in many forums over the past several years. As ACTS completes its final experiments activity, this paper will relate the top-level program goals that have been achieved in the design, operation, and performance of the particular satellite subsystems. Pre-launch decisions to ensure satellite reliability and the subsequent operational experiences contribute to lessons learned that may be applicable to other comsat programs.

  9. 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…

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

    ERIC Educational Resources Information Center

    Ohlman, Herbert

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

  11. Inmarsat - A new global maritime satellite communications system

    NASA Astrophysics Data System (ADS)

    Nicolaidis, E.

    1982-07-01

    In response to increasing communication demands related to the presence of a large number of ships at sea, the Assembly of the Inter-Governmental Maritime Consultative Organization (IMCO), a specialized agency of the United Nations, convened in 1973 the International Conference on the Establishment of an International Maritime Satellite System. The chain of events set in motion in connection with this conference culminated in the birth of the International Maritime Satellite Organization (Inmarsat). Inmarsat came into being on July 16, 1979. The purpose of Inmarsat is to make provision for the space segment necessary for improving maritime communications, thereby assisting in improving communications for distress and safety of life at sea, efficiency and management of ships, maritime public correspondence services, and radio determination capabilities. The Inmarsat system went into operation on February 1, 1982, taking over from the American Marisat system which had provided a similar service since 1976.

  12. Concepts for 18/30 GHz satellite communication system, volume 1

    NASA Technical Reports Server (NTRS)

    Jorasch, R.; Baker, M.; Davies, R.; Cuccia, L.; Mitchell, C.

    1979-01-01

    Concepts for 18/30 GHz satellite communication systems are presented. Major terminal trunking as well as direct-to-user configurations were evaluated. Critical technologies in support of millimeter wave satellite communications were determined.

  13. 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.

  14. Advanced Communications Technology Satellite Now Operating in an Inclined Orbit

    NASA Technical Reports Server (NTRS)

    Bauer, Robert A.

    1999-01-01

    The Advanced Communications Technology Satellite (ACTS) system has been modified to support operation in an inclined orbit that is virtually transparent to users, and plans are to continue this final phase of its operation through September 2000. The next 2 years of ACTS will provide a new opportunity for using the technologies that this system brought online over 5 years ago and that are still being used to resolve the technical issues that face NASA and the satellite industry in the area of seamless networking and interoperability with terrestrial systems. New goals for ACTS have been defined that align the program with recent changes in NASA and industry. ACTS will be used as a testbed to: Show how NASA and other Government agencies can use commercial systems for 1. future support of their operations Test, characterize, and resolve technical issues in using advanced communications 2. protocols such as asynchronous transfer mode (ATM) and transmission control protocol/Internet protocol (TCP/IP) over long latency links as found when interoperating satellites with terrestrial systems Evaluate narrow-spot-beam Ka-band satellite operation in an inclined orbit 3. Verify Ka-band satellite technologies since no other Ka-band system is yet 4. available in the United States

  15. 22 CFR 123.27 - Special licensing regime for export to U.S. allies of commercial communications satellite...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

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

  16. 22 CFR 123.27 - Special licensing regime for export to U.S. allies of commercial communications satellite...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

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

  17. 22 CFR 123.27 - Special licensing regime for export to U.S. allies of commercial communications satellite...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    .... allies of commercial communications satellite components, systems, parts, accessories, attachments and... licensing regime for export to U.S. allies of commercial communications satellite components, systems, parts... and certain associated technical data for commercial communications satellites, and who are...

  18. 22 CFR 123.27 - Special licensing regime for export to U.S. allies of commercial communications satellite...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  19. 22 CFR 123.27 - Special licensing regime for export to U.S. allies of commercial communications satellite...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

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

  20. 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.

  1. Comprehensive testing of a defense systems communications satellite

    NASA Technical Reports Server (NTRS)

    Shirk, N. K.; Keer, S. J.

    1980-01-01

    The system level testing of the defense satellite communications system (DSCS) 3 program is reviewed. Concentration is on the results of the systems tests of the DSCS 3 development test model (DTM). The DSCS 3DTM consisted of engineering components interconnected in an open bench layout. The DTM tests were performed to demonstrate satellite electrical performance characteristics and to uncover design deficiencies and interface problems. The availability of the DTM test results prior to the fabrication of the flight model hardware permited the incorporation of necessary design changes with a minimum impact on program costs and schedules.

  2. System issues related to satellite communications in a nuclear environment

    SciTech Connect

    Kullstam, P.A.

    1990-05-03

    Nuclear induced signal scintillation effects are of great importance in design and deployment of military satellite systems that must provide survivable and enduring communications service. The induced scintillation will result in Rayleigh signal fading with limited signal decorrelation time and coherent bandwidth of the transmission channel as well as reduced signal power due to terminal antenna scattering loss. In this environment the coherent bandwidth and signal decorrelation time are most important design parameters for modulation subsystem design. The antenna scattering loss is important for link power budgets and satellite network loading.

  3. Market Related System Analysis of Satellite Communication Networks

    NASA Astrophysics Data System (ADS)

    Malyshev, V. V.; Panasenkova, M. V.

    2002-01-01

    The report is devoted to the technique of effectiveness analysis of communication space system with satellites in geostationary orbit using market models. The technique is worked out in order to choose the most optimal alternative of communication space system design. The alternative considered optimal and the system effective when the maximum profit from the system with limited system costs is achieved. The key point of the technique is a wide use of market models and application of market related parameters as an integral part of the design technique in order to secure the high commercial output of the communication space system. A range of models for decisive characteristics of communication space system is synthesized in terms of the technique. Flexible market model with detailed insight into the structure of the given market sector and its trends is created. The technique enables to choose the image and key parameters of the future system such as payload and ground sector characteristics so as to make the system most cost-effective and profitable. It is shown that such factors as the choice of launch vehicle can influence the system effectiveness rather dramatically. In particular, it is shown that under certain conditions delivering the small (five hundred kg) satellite to the geostationary orbit with the help of light-weight launch vehicle and the satellite's own electro-rocket thrusters is forty per cent more cost- effective than when the satellite is delivered with the help of the medium-size launch vehicle. The latter case can lead to the significant losses due to high launch costs that are nearly two times higher for the medium size launch vehicle than for the light launce vehicle. The technique is applicable both for designing a wide range of communication space systems and is recommended for those dealing with designing commercial systems. It can also be used to update and improve the systems that are already in operation.

  4. 77 FR 58579 - Certain Two-Way Global Satellite Communication Devices, System and Components Thereof...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-21

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

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

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

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

  6. 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.

  7. The 30/20 GHz communications satellite trunking network study

    NASA Technical Reports Server (NTRS)

    Kolb, W.

    1981-01-01

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

  8. First satellite mobile communication trials using BLQS-CDMA

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  9. Electric Propulsion for Low Earth Orbit Communication Satellites

    NASA Technical Reports Server (NTRS)

    Oleson, Steven R.

    1997-01-01

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

  10. 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.

  11. Characteristics of a future aeronautical satellite communications system

    NASA Technical Reports Server (NTRS)

    Sohn, Philip Y.; Stern, Alan; Schmidt, Fred

    1991-01-01

    A possible operational system scenario for providing satellite communications services to the future aviation community was analyzed. The system concept relies on a Ka-band (20/30 GHz) satellite that utilizes multibeam antenna (MBA) technology. The aircraft terminal uses an extremely small aperture antenna as a result of using this higher spectrum at Ka-band. The satellite functions as a relay between the aircraft and the ground stations. The ground stations function as interfaces to the existing terrestrial networks such as the Public Service Telephone Network (PSTN). Various system tradeoffs are first examined to ensure optimized system parameters. High level performance specifications and design approaches are generated for the space, ground, and aeronautical elements in the system. Both technical and economical issues affecting the feasibility of the studied concept are addressed with the 1995 timeframe in mind.

  12. Characteristics of a future aeronautical satellite communications system

    NASA Technical Reports Server (NTRS)

    Sohn, Philip Y.; Stern, Alan; Schmidt, Fred

    1991-01-01

    A possible operational system scenario for providing satellite communications services to the future aviation community was analyzed. The system concept relies on a Ka-band (20/30 GHz) satellite that utilizes Multibeam Antenna (MBA) technology. The aircraft terminal uses an extremely small aperture antenna as a result of using this higher spectrum at Ka-band. The satellite functions as a relay between the aircraft and the ground stations. The ground stations function as interfaces to the existing terrestrial networks such as the Public Service Telephone Network (PSTN). Various system tradeoffs are first examined to ensure optimized system parameters. High level performance specifications and design approaches are generated for the space, ground, and aeronautical elements in the system. Both technical and economical issues affecting the feasibility of the studied concept are addressed with the 1995 timeframe in mind.

  13. Atmospheric attenuation for correlated satellite communication ground sites

    NASA Technical Reports Server (NTRS)

    Christopher, P.

    1983-01-01

    Link margin estimates are calculated for 30/20 GHz satellite communication systems employing closely-spaced (4 to 100 km) 'dual diversity' switched ground sites. The link margin estimates are based on a new analysis in which the bivariate rain attenuation density function for two correlated ground sites is modelled by an exponential density function. The results of the exponential density function analysis enable derivation of a direct relation between rain margin estimates and probability of exceedance (link availability). Margins typically in the range 2 to 12 dB are calculated for various ground site separations and summarized for seven city locations and five satellite orbit positions over the U.S. The results can be easily extended to other EHF satellite frequencies and other locations.

  14. A LEO concept for millimeter wave satellite communication

    NASA Technical Reports Server (NTRS)

    Jackson, A. H.; Christopher, P.

    1995-01-01

    A conceptual 60 satellite LEO constellation for millimeter wave communication is discussed. It could be launched in segments, with the first 30 satellites providing high elevation angles for all time in the Northern latitudes between Miami and Thule. The second set of 30 satellites would complete the worldwide coverage with emphasis on high ground elevation angles in the densely populated temperate zones. Full earth searches for all time are used to generate probability density functions for elevation angle. The density functions are used to derive optimum frequencies for random elevation systems. The 55 degree average elevation angle and 14 degree standard deviation are seen to be acceptable for 0.997 rain availability in Washington, DC for the 40 to 47 GHz region. The 40 to 47 GHz region is nearly optimum, if 0.99 rain availability is acceptable.

  15. 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.

  16. Design and performance of a repeater for optical satellite communication

    NASA Astrophysics Data System (ADS)

    Ohm, G.; Wiesmann, Th.; Hieber, E.

    General design aspects of optical inter-satellite and inter-orbit links and the choice of technology for data relay applications are described. A first step toward optical links is the ESA in-orbit experiment SILEX which is briefly reviewed with emphasis on the communication subsystem. All relevant equipments of the communication subsystem, which is based on 0.85-micron laser diodes, QPPM data format, and direct detection, have been developed and tested. Using the equipment developed, an experimental repeater was assembled and investigated. Measured and simulated results are in close agreement, and no major critical events occurred during the development and test activities.

  17. 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.

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

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

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

  19. 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.

  20. Hall Thruster Impact Analysis on Digital Satellite Communications

    NASA Astrophysics Data System (ADS)

    Zuniga, C. D.; Hallock, G. A.; Wiley, J. C.; Meyer, J. W.; Loane, J. T.

    2002-11-01

    Hall Thrusters will be used for stationkeeping of geosynchronous communications satellites. These thrusters produce an inhomogeneous plasma plume which may interfere with communications signals (1-20 GHz) to and from the satellite. The plume's effects include beam-pointing error, beam attenuation, and spectral modulation [1]. Many systems digitally modulate an RF carrier and use coherent detection methods. The plasma may degrade the performance of these systems by diminishing the SNR at the receiver by squinting the beam away and degrading the synchronization by phase modulating the signal. We simulate a receiver whose input signals have been corrupted by the plasma plume. These modified input signals are formed by using the results of a previously developed ray tracing code [1]. We will present performance measures including bit-error rates and link availability. * Work supported by Lockheed Martin Corp. and the Texas Higher Education Coordinating Board. [1] Hallock et al, J. Spacecraft and Rockets V. 39 No 1 pp 115-124

  1. On effectiveness of routing algorithms for satellite communication networks

    NASA Astrophysics Data System (ADS)

    Yu, Wei; Wei, Sixiao; Xu, Guobin; Chen, Genshe; Pham, Khanh; Blasch, Erik P.; Lu, Chao

    2013-05-01

    For worldwide, a satellite communication network is an integral component of the global networking infrastructure. In this paper, we focus on developing effective routing techniques that consider both user preferences and network dynamic conditions. In particular, we develop a weighted-based route selection scheme for the core satellite communication network. Unlike the shortest path routing scheme, our scheme chooses the route from multiple matched entries based on the assigned weights that reflect the dynamic condition of networks. We also discuss how to derive the optimal weights for route assignment. To further meet user's preference, we implement the multiple path routing scheme to achieve the high rate of data transmission and the preemption based routing scheme to guarantee the data transmission for high priority users. Through extensive simulation studies, our data validates the effectiveness of our proposed routing schemes.

  2. Concept for advanced satellite communications and required technologies

    NASA Technical Reports Server (NTRS)

    Ramler, J. R.; Salzman, J. A.

    1982-01-01

    The advanced communications technology satellite (ACTS) program of NASA is aimed at the development of high risk technologies that will enable exploiting higher frequency bands and techniques for improving frequency reuse. The technologies under development include multiple beam spacecraft antennas, on-board switching and processing, RF devices and components and advanced earth stations. The program focus is on the Ka-band (30/20 GHz) as the implementing frequency since it has five times the bandwidth of either the C- or Ku-bands. However, the technology being developed is applicable to other frequency bands as well and will support a wide range of future communications systems required by NASA, other Government agencies and the commercial sector. An overview is presented of an operational 30/20 GHz satellite system that may evolve. How the system addresses service requirements is discussed, and the technology required and being developed is considered. Previously announced in STAR as N83-11210

  3. Concept for advanced satellite communications and required technologies

    NASA Technical Reports Server (NTRS)

    Ramler, J. R.; Salzman, J. A.

    1982-01-01

    The advanced communications technology satellite (ACTS) program of NASA is aimed at the development of high risk technologies that will enable exploiting higher frequency bands and techniques for improving frequency reuse. The technologies under development include multiple beam spacecraft antennas, on-board switching and processing, RF devices and components and advanced Earth stations. The program focus is on the Ka-band (30/20 GHz) as the implementing frequency since it has five times the bandwidth of either the C- or Ku-bands. However, the technology being developed is applicable to other frequency bands as well and will support a wide range of future communications systems required by NASA, other Government agencies and the commercial sector. An overview is presented of an operational 30/20 GHz satellite system that may evolve. How the system addresses service requirements is discussed, and the technology required and being developed is considered.

  4. FEC decoder design optimization for mobile satellite communications

    NASA Technical Reports Server (NTRS)

    Roy, Ashim; Lewi, Leng

    1990-01-01

    A new telecommunications service for location determination via satellite is being proposed for the continental USA and Europe, which provides users with the capability to find the location of, and communicate from, a moving vehicle to a central hub and vice versa. This communications system is expected to operate in an extremely noisy channel in the presence of fading. In order to achieve high levels of data integrity, it is essential to employ forward error correcting (FEC) encoding and decoding techniques in such mobile satellite systems. A constraint length k = 7 FEC decoder has been implemented in a single chip for such systems. The single chip implementation of the maximum likelihood decoder helps to minimize the cost, size, and power consumption, and improves the bit error rate (BER) performance of the mobile earth terminal (MET).

  5. FEC decoder design optimization for mobile satellite communications

    NASA Astrophysics Data System (ADS)

    Roy, Ashim; Lewi, Leng

    A new telecommunications service for location determination via satellite is being proposed for the continental USA and Europe, which provides users with the capability to find the location of, and communicate from, a moving vehicle to a central hub and vice versa. This communications system is expected to operate in an extremely noisy channel in the presence of fading. In order to achieve high levels of data integrity, it is essential to employ forward error correcting (FEC) encoding and decoding techniques in such mobile satellite systems. A constraint length k = 7 FEC decoder has been implemented in a single chip for such systems. The single chip implementation of the maximum likelihood decoder helps to minimize the cost, size, and power consumption, and improves the bit error rate (BER) performance of the mobile earth terminal (MET).

  6. Attitude Control Subsystem for the Advanced Communications Technology Satellite

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

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

  7. Mechanical environmental test program for the Communications Technology Satellite

    NASA Technical Reports Server (NTRS)

    Buckingham, R.; Sharp, G. R.

    1974-01-01

    This paper describes the spacecraft and subsystem level mechanical environmental test program which was developed for the Communications Technology Satellite (CTS). At the spacecraft level it includes sine and random vibration, static loading, centrifuge loading, pyrotechnic and separation shock simulation and (tentatively) acoustics. At the subsystem level it entails the same type of environmental exposure as applicable. Matrices of system and subsystem tests are presented showing type, level and hardware status for each major test.

  8. Communications technology satellite - A variable conductance heat pipe application

    NASA Technical Reports Server (NTRS)

    Mock, P. R.; Marcus, B. D.; Edelman, E. A.

    1974-01-01

    A variable-conductance heat pipe system (VCHPS) has been designed to provide thermal control for a transmitter experiment package (TEP) to be flown on the Communications Technology Satellite. The VCHPS provides for heat rejection during TEP operation and minimizes the heat leak during power down operations. The VCHPS described features a unique method of aiding priming of arterial heat pipes and a novel approach to balancing heat pipe loads by staggering their control ranges.

  9. Trellis-coded CPM for satellite-based mobile communications

    NASA Technical Reports Server (NTRS)

    Abrishamkar, Farrokh; Biglieri, Ezio

    1988-01-01

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

  10. Automated testing of developmental satellite communications systems and subsystems

    NASA Technical Reports Server (NTRS)

    Shalkhauser, K. A.; Kerczewski, R. J.

    1985-01-01

    Lower frequency bands allocated for satellite communications use are becoming saturated due to steadily increasing demand. An ongoing program to develop the new technologies required to meet the demands of future systems is described. Higher frequency components and more efficient system techniques are developed. In order to accurately evaluate the performance of these technologies, an automated test system was designed and built. The automated system's design an capabilities are discussed.

  11. Error control techniques for satellite and space communications

    NASA Technical Reports Server (NTRS)

    Costello, Daniel J., Jr.

    1991-01-01

    Research activities related to error control techniques for satellite and space communication are reported. Specific areas of research include: coding gains for bandwidth efficient codes, hardware implementation of a bandwidth efficient coding scheme for the Hubble Space Telescope, construction of long trellis codes for use with sequential decoding, performance analysis of multilevel trellis codes, and M-algorithm decoding of trellis codes. Each topic is discussed in a corresponding paper that appears in the appendices.

  12. Frequencies above 10 GHz. [for satellite communication services

    NASA Technical Reports Server (NTRS)

    Mcavoy, N.

    1976-01-01

    The paper discusses some of the problems associated with extending the frequencies used by satellite communication services above 10 GHz. The principal propagation limitation above 10 GHz occurs when precipitation intercepts the earth-space propagation path and causes attenuation and depolarization of the transmitted signal. World attenuation statistics at 12 GHz for earth-space paths are discussed, revealing the effect of climate on attenuation properties. Space diversity is discussed as an effective means of overcoming precipitation-caused attenuation problems.

  13. Proceedings of the Advanced Communications Technology Satellite (ACTS) Conference 2000

    NASA Technical Reports Server (NTRS)

    Bauer, Robert (Editor); Derwae, Robert (Editor)

    2000-01-01

    The ACTS experiments program, which began in December 1993 and consisted of 103 different experiments, has made significant contributions to minimizing the risk of advanced satellite communications technology. The ACTS Conference 2000 (AC2000) was held to report the results of the program since the last ACTS conference was held in 1995 and to celebrate the end of a very successful satellite program. The conference was held on May 31, 2000, as part of the 6th Ka-band Utilization Conference in Cleveland, Ohio. Approximately 280 representatives of industry, academia, and government attended. The conference was organized into two parts: a technical session during the day and an evening reception. During the day, a series of five technical sessions included presentations of 17 papers covering the results of the experiment activity and technical performance of the satellite. In the evening, a reception was held to celebrate the end of the ACTS Experiments Program on one of NASA's most successful experimental communications satellite. These proceedings were developed to capture the entire event, including the evening reception.

  14. 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.

  15. Results of computer network experiment via the Japanese communication satellite CS - Performance evaluation of communication protocols

    NASA Astrophysics Data System (ADS)

    Ito, A.; Kakinuma, Y.; Uchida, K.; Matsumoto, K.; Takahashi, H.

    1984-03-01

    Computer network experiments have been performed by using the Japanese communication satellite CS. The network is of a centralized (star) type, consisting of one center station and many user stations. The protocols are determined taking into consideration the long round trip delay of a satellite channel. This paper treats the communication protocol aspects of the experiments. Performances of the burst level and the link protocols (which correspond nearly to data link layer of OSI 7 layer model) are evaluated. System performances of throughput, delay, link level overhead are measured by using the statistically generated traffic.

  16. David Florida Laboratory: Support for mobile satellite communications

    NASA Technical Reports Server (NTRS)

    Dumoulin, Jean-Guy; Mamen, Rolf

    1995-01-01

    The comprehensive integration and environmental (including RF) test facilities of the Canadian Space Agency's David Florida Laboratory (CSA)(DFL) were used extensively for the MSAT Program. Following a description of the facilities, the paper outlines their application to the qualification of the two MSAT satellites following an overview of the test plan. Particular emphasis is given to passive intermodulation measurement (PIM) demands, which for the MSAT satellites, contributed to the need to extend the anechoic chamber. The extended chamber was also used for an EMC test and SAR signature test of the RADARSAT satellite. The DFL's facilities are being used for additional aspects of mobile satellite communications. One shielded anechoic Extra High Frequency (EHF) chamber and associated test equipment are employed predominantly for measuring the performance of the IRIDIUM satellites' Engineering Model Gateway Moveable Antennas (EM)(GMA). Other chambers are used for testing aeronautical antennas on behalf of Inmarsat. Still others combine thermal and PIM testing. The paper concludes with a review of the test requirements of evolving satcom missions such as Inmarsat Aero-1.

  17. 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.

  18. Hybrid Global Communication Architecture with Balloons and Satellites

    NASA Astrophysics Data System (ADS)

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

    2002-01-01

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

  19. System design for the digitally implemented communications experiment /DICE/. [Communications Technology Satellite television for teleconferencing

    NASA Technical Reports Server (NTRS)

    Gatfield, A. G.; Suyderhoud, H. G.; Wolejsza, C. J., Jr.

    1977-01-01

    Full-duplex digital television providing a teleconference capability is to be evaluated in an experimental program utilizing the Communications Technology Satellite. The digitally implemented communications experiment employs a QPSK modulator-demodulator capable of operation over a wide range of bit rates. In addition to simultaneous data transmission (used for digital high-speed facsimiles and remote computer terminals), voice transmission through four-to-one compression will be studied.

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

    NASA Astrophysics Data System (ADS)

    Subhani, Noman

    2016-07-01

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

  1. Bispectrum modulation for jamming rejection on satellite communication channels

    NASA Astrophysics Data System (ADS)

    Barton, Richard J.

    1995-05-01

    The Global Grid communications environment is designed to provide a high-data-rate network that supports the full complement of DoD communications needs. Satellite links are an integral part of the Global Grid concept which extends the connectivity to individual mobile units and jointly operating forces at isolated locations. However, satellite channels are vulnerable to jamming, in particular when a high data rate is required. To overcome the jamming problem, the traditional approach is to design modulation techniques such that, on the average, the spectrum of the signal looks like the spectrum of a white noise process. This together with channel coding provides immunity against jamming. The main problem with this approach is that it requires a much larger spectrum than that of the data sequence; hence, the available spectrum on the link is used mostly for jamming protection and not for data communications. The traditional modulation techniques employed on satellite communication links are based on various properties of the second-order spectrum of the modulation wave form. In this study we have explored the utility and performance of a new family of modulation schemes that exploit the properties of the higher-order cumulant sequences and associated polyspectra of the waveform. In particular, we have investigated an approach in which the third-order polyspectrum, which is generally referred to as the bispectrum, is modulated. To determine the performance characteristics of this bispectral modulation scheme, we have considered two different detector structures, for which we have completed both theoretical and simulated performance analyses.

  2. 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.

  3. 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…

  4. Physical characteristics of geosynchronous high power communications satellites

    SciTech Connect

    Drackett, T.M.

    1995-12-31

    With the advent of the Information Superhighway, many organizations have been spurred into re-examining current spacecraft architectures to determine how the significantly higher communications capacities of the future will be accommodated. Opinion is divided on many issues in this arena, and none more so than the discussion that revolves around whether several large satellites in Geosynchronous Orbit (GEO) offer a better all-round service to the user community than a fleet of small satellites in Low Earth Orbit (LEO). Although this paper does not attempt to debate this particular issue, a clear finding of the work carried out by the author and others, was that considerable growth potential exists by simply increasing the physical size and capacity of conventional geosynchronous satellites while causing a minimal impact on existing ground systems and infrastructures. The work described here forms part of a power systems study carried out by Lockheed Martin Astro Space (Astro), and funded by the Department of Energy (DOE), to investigate how photovoltaic and reactor based power technology can be applied to spacecraft with payloads in the 20 kW to 100 kW range. The scope of this paper is to address how the payload type, power source technology and launch vehicle selection influence the physical characteristics of satellites with payloads of this magnitude.

  5. 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.

  6. Hybrid system of communication and radio determination using two geostationary satellites

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

    A new hybrid satellite system which can provide both communications and positioning services in one system using two geostationary satellites is discussed. The distinctive feature is that location information can be provided by transmitting and receiving ranging signals over the same channel as communications through two geostationary satellites.

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

    ERIC Educational Resources Information Center

    Richmond, J. Murray

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

  8. Study of repeater technology for advanced multifunctional communications satellites

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Investigations are presented concerning design concepts and implementation approaches for the satellite communication repeater subsystems of advanced multifunctional satellites. In such systems the important concepts are the use of multiple antenna beams, repeater switching (routing), and efficient spectrum utilization through frequency reuse. An information base on these techniques was developed and tradeoff analyses were made of repeater design concepts, with the work design taken in a broad sense to include modulation beam coverage patterns. There were five major areas of study: requirements analysis and processing; study of interbeam interference in multibeam systems; characterization of multiple-beam switching repeaters; estimation of repeater weight and power for a number of alternatives; and tradeoff analyses based on these weight and power data.

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

    NASA Astrophysics Data System (ADS)

    Brandon, W. T.; White, B. E.

    1980-05-01

    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.

  10. Modulation and coding for satellite and space communications

    NASA Astrophysics Data System (ADS)

    Yuen, Joseph H.; Simon, Marvin K.; Pollara, Fabrizio; Divsalar, Dariush; Miller, Warner H.; Morakis, James C.; Ryan, Carl R.

    1990-07-01

    Several modulation and coding advances supported by NASA are summarized. To support long-constraint-length convolutional code, a VLSI maximum-likelihood decoder, utilizing parallel processing techniques, which is being developed to decode convolutional codes of constraint length 15 and a code rate as low as 1/6 is discussed. A VLSI high-speed 8-b Reed-Solomon decoder which is being developed for advanced tracking and data relay satellite (ATDRS) applications is discussed. A 300-Mb/s modem with continuous phase modulation (CPM) and codings which is being developed for ATDRS is discussed. Trellis-coded modulation (TCM) techniques are discussed for satellite-based mobile communication applications.

  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. Enhanced TCP for maritime communications over satellite network

    NASA Astrophysics Data System (ADS)

    Zong, Liang; Du, Wencai; Bai, Yong

    2014-10-01

    For maritime communications over satellite network, TCP performance is essential for data transmissions. TCP ADaLR is congestion control algorithm that the sender judgments the relevant window change and measures roundtrip time to control congestion window. It can adapt to the characteristics of the satellite link and improve the performance of TCP than conventional TCP. However, it does not take into account distinction of random packet loss and congestion loss like TCP Veno. In this paper, we propose further enhancement of TCP ADaLR, called TCP ADaLR+, that can distinguish between random packet loss and congestion loss. The improved performance of proposed TCP ADaLR+ is demonstrated by simulations.

  13. ACTS TDMA network control. [Advanced Communication Technology Satellite

    NASA Technical Reports Server (NTRS)

    Inukai, T.; Campanella, S. J.

    1984-01-01

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

  14. Modulation and coding for satellite and space communications

    NASA Technical Reports Server (NTRS)

    Yuen, Joseph H.; Simon, Marvin K.; Pollara, Fabrizio; Divsalar, Dariush; Miller, Warner H.; Morakis, James C.; Ryan, Carl R.

    1990-01-01

    Several modulation and coding advances supported by NASA are summarized. To support long-constraint-length convolutional code, a VLSI maximum-likelihood decoder, utilizing parallel processing techniques, which is being developed to decode convolutional codes of constraint length 15 and a code rate as low as 1/6 is discussed. A VLSI high-speed 8-b Reed-Solomon decoder which is being developed for advanced tracking and data relay satellite (ATDRS) applications is discussed. A 300-Mb/s modem with continuous phase modulation (CPM) and codings which is being developed for ATDRS is discussed. Trellis-coded modulation (TCM) techniques are discussed for satellite-based mobile communication applications.

  15. Chaos Based Secure IP Communications over Satellite DVB

    NASA Astrophysics Data System (ADS)

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

    2010-06-01

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

  16. 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.

  17. 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

  18. 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.

  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. 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.

  1. The use of satellites in non-goestationary orbits for unloading geostationary communication satellite traffic peaks. Volume 2: Technical report

    NASA Technical Reports Server (NTRS)

    Price, K.; Turner, A.; Nguyen, T.; Doong, W.; Weyandt, C.

    1987-01-01

    The part of the geostationary (GEO) orbital arc used for United States domestic fixed, communications service is rapidly becoming filled with satellites. One of the factors currently limiting its utilization is that communications satellites must be designed to have sufficient capacity to handle peak traffic leads, and thus are under utilized most of the time. A solution is to use satellites in suitable non-geostationary orbits to unload the traffic peaks. Three different designs for a non-geostationary orbit communications satellite system are presented for the 1995 time frame. The economic performance is analyzed and compared with geostationary satellites for two classes of service, trunking and customer premise service. The result is that the larger payload of the non-geostationary satellite offsets the burdens of increased complexity and worse radiation environment to give improved economic performance. Depending on ground terminal configuration, the improved economic performance of the space segment may be offset by increased ground terminal expenses.

  2. Crosstalk cancellation on linearly and circularly polarized communications satellite links

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

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

  3. Why is CDMA the solution for mobile satellite communication

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  4. 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.

  5. Coordination procedure for radio relay and communication satellite services

    NASA Technical Reports Server (NTRS)

    Eckerman, J.

    1973-01-01

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

  6. 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.

  7. The 30/20 GHz experimental communications satellite system

    NASA Technical Reports Server (NTRS)

    Sivo, J. N.

    1981-01-01

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

  8. 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.

  9. More About Lens Antenna For Mobile/Satellite Communication

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

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

  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. Effect of digital scrambling on satellite communication links

    NASA Technical Reports Server (NTRS)

    Dessouky, K.

    1985-01-01

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

  12. Antenna design for the Inmarsat second generation communication satellites

    NASA Astrophysics Data System (ADS)

    Huang, C. C.; McDonach, C. A.

    1990-02-01

    The Inmarsat satellite system provides international marine communications. This paper presents the RF design of a family of three antennas giving global coverage for the second generation of Inmarsat spacecraft. The antennas are direct radiating arrays operating at L-band and C-band with circular polarization. A very stringent low profile requirement is achieved by the use of cup-dipole radiators and integrated feed technology. The design of the cup-dipole is presented in detail together with the trade-offs leading to its selection as the radiating element. The measured antenna performance for all three arrays is presented showing good agreement with theoretical predictions.

  13. 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.

  14. 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

  15. Subjective voice quality evaluation in a satellite communications environment

    NASA Astrophysics Data System (ADS)

    Farinholt, E. V.; Lavalley, R. W.; Hardy, W. C.

    The development of a subjective test procedure for evaluating voice quality is described. The technical characteristics of the satellite communication system are analyzed in order to identify the factors that impair voice quality. The factors that affect the system are: (1) low volume, (2) constant noise, (3) busting noise, (4) noise on speech, (5) speech distortion, (6) incomplete words, (7) garbling, (8) mutual interpretation, and (9) echo. The communication system was rated by test callers based on the occurrence of each noise impairment, the effect of the impairments on the call quality, and the overall quality of the call. Analysis of the data reveals that it is feasible to develop a voice quality evaluation system based on electronic measurements of parameters that predict the occurrence and severity of the nine impairments.

  16. An overview of the NASA satellite communications program

    NASA Technical Reports Server (NTRS)

    Dement, D. K.

    1979-01-01

    This overview sets the framework for five descriptive papers from NASA Field Centers where satellite communications research and development is being conducted. A review of events of 1973-78 in the Federal Government, in industry, and in professional organizations are shown to have contributed to the formulation of new policy supporting the establishment of renewed efforts within NASA toward improved use of the spectrum and orbit for communications. The work will focus on the development of 'frequency re-use' technology, including multi-beam antennas and on-board switching for future spacecraft. This paper treats the planning issues and the approaches taken toward forming a coherent program from the sustaining efforts of the recent past. Companion papers highlight the methods, the technology, and the activities that are assisting in the transition to a new program.

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

    NASA Astrophysics Data System (ADS)

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

    1985-01-01

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

  18. The communication-satellite market to the year 2000

    NASA Astrophysics Data System (ADS)

    van Duinen, R. J.

    1984-10-01

    The developmental history of communication satellites (CSs) is traced; the demands placed on industry by the increasing sophistication of CS payloads, the need to adapt the CS to different launchers (STS or Ariane), and the requirement of longer service life are reviewed; and the evolution of the markets for fixed (telephone, telex, and facsimile), video, business, and broadcasting service is projected over the period 1980-2000 and illustrated with tables and graphs. It is predicted that the worldwide market, expressed in terms of the demand for 36-Mhz transponders, will increase from 426 in 1980 to 1410 in 1985, 3100 in 1990, 5580 in 1995, and 9870 in 2000, with the main increase in transponders for voice communications. The potential for Netherlands participation in the growth of the CS market is evaluated, and the need for government leadership and for active promotion efforts is stressed.

  19. 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.

  20. Satellite Communications for U.S. Schools; A Proposed Public Service Offering by Private Business.

    ERIC Educational Resources Information Center

    Krause, Lloyd I.

    The Federal Communications Commission has asked that companies seeking authorization to construct and operate communications satellite facilities for multi-purpose commercial uses in the United States give consideration to the communications needs of schools. In response to this request, MCI Lockheed Satellite Corporation proposes a low-cost…

  1. 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.

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

    NASA Astrophysics Data System (ADS)

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

    1981-05-01

    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.

  3. 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.

  4. Next generation communications satellites: Multiple access and network studies

    NASA Technical Reports Server (NTRS)

    Stern, T. E.; Schwartz, M.; Meadows, H. E.; Ahmadi, H. K.; Gadre, J. G.; Gopal, I. S.; Matsmo, K.

    1980-01-01

    Following an overview of issues involved in the choice of promising system architectures for efficient communication with multiple small inexpensive Earth stations serving hetergeneous user populations, performance evaluation via analysis and simulation for six SS/TDMA (satellite-switched/time-division multiple access) system architectures is discussed. These configurations are chosen to exemplify the essential alternatives available in system design. Although the performance evaluation analyses are of fairly general applicability, whenever possible they are considered in the context of NASA's 30/20 GHz studies. Packet switched systems are considered, with the assumption that only a part of transponder capacit is devoted to packets, the integration of circuit and packet switched traffic being reserved for further study. Three types of station access are distinguished: fixed (FA), demand (DA), and random access (RA). Similarly, switching in the satellite can be assigned on a fixed (FS) or demand (DS) basis, or replaced by a buffered store-and-forward system (SF) onboard the satellite. Since not all access/switching combinations are practical, six systems are analyzed in detail: three FS SYSTEMS, FA/FS, DA/ES, RA/FS; one DS system, DA/DS; and two SF systems, FA/SF, DA/SF. Results are presented primarily in terms of delay-throughput characteristics.

  5. 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.

  6. Optimizing communication satellites payload configuration with exact approaches

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

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

    NASA Technical Reports Server (NTRS)

    Leonard, R. F.; Kerczewski, R.

    1985-01-01

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

  8. Comparison of satellite and fiber optics technologies for intercity and intercontinental communications

    NASA Astrophysics Data System (ADS)

    Sharifi, M. Hossein; Arozullah, Mohammed

    The applications of satellite and fiber optic technologies to the design of intercity and intercontinental communications networks are examined. Satellite technology including space and ground segments, and advancements and operational requirements for underwater and land fiber optics communications systems are discussed. Communications satellites and fiber optics are compared in terms of physical implementation, switching requirements, transmission parameters, availability, cost, system flexibility, transmission quality, and applications. The cost of point-to-point transmission of 60 Mbps data using satellite, fiber optics, and microwave systems is evaluated. It is observed that satellite systems are the most cost-effective and flexible methods for providing transmission media for distances greater than about 700 km.

  9. 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.

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

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

  11. Free-space optical communication satellite networks-vibration effects and possible solutions

    NASA Astrophysics Data System (ADS)

    Arnon, Shlomi; Kopeika, Norman S.

    1997-07-01

    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 inter satellite links in those project use microwave radiation as the carrier. Free space optical communication between satellites networked together can make possible high speed communications between different places on earth. The advantages of an optical communication system instead of a microwave communication system in free space are: (1) smaller size and weight, (2) less transmitter power, (3) larger bandwidth, (4) higher immunity to interference, and (5) smaller transmitter beam divergence. 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 problem is more complicated due to vibration of the pointing system caused by two stochastic fundamental mechanisms (1) tracking noise created by the electrooptic tracker and (2) vibrations created by internal and external mechanical mechanisms. The vibrations displace the transmitted beam in the receiver plane. Such movement of the transmitted beam in the receiver plane decreases the average received signal which decreases increases the bit error rate. In this paper we review: (1) the present status of satellite networks, (2) developing efforts of optical satellite communication around the world, (3) performance results of vibration effects on different kinds of optical communication satellite networks and (4) seven approaches to overcome the problems caused by transmitter pointing vibration.

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

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Benet, James

    1993-01-01

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

  14. Earth Science Mission Benefits of High Data Rate Satellite Communications

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  15. High Data Rate Satellite Communications for Environmental Remote Sensing

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-08-01

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

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

    NASA Technical Reports Server (NTRS)

    Gutierrez, Alberto, Jr.

    1995-01-01

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

  18. Spacecraft design project: Low Earth orbit communications satellite

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

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

  19. Power processing system for a 200 watt communication satellite transmitter

    NASA Technical Reports Server (NTRS)

    Farber, B. F.; Schoenfeld, A. D.; Thollot, P. A.

    1975-01-01

    A power processing system (PPS) for a communication satellite, high power (200W RF) multi-stage depressed collector, 12 GHz, traveling wave tube, is described. The PPS converts spacecraft bus power at a nominal voltage of 76 Vdc to the levels necessary for operating a ten-collector coupled cavity TWT requiring approximately 500 watts of input power. Regulated voltages of up to -11.3K Vdc are provided along with command, protection and telemetry signal conditioning circuits. Power processor interface requirements are set forth and a block diagram illustrating the basic approach utilized is presented. Overall performance, design characteristics and unique features are discussed. Thermal and mechanical interface requirements impacting on PPS design are described as well as the thermal control technique utilized for the overall PPS/TWT assembly.

  20. Computer simulation of digital signal modulation techniques in satellite communications

    NASA Astrophysics Data System (ADS)

    Carlson, C. D.

    1985-09-01

    Tutorial on digital signal modulation techniques used in satellite communications is presented and includes computer simulation of those digital signal modulation techniques introduced. The purpose is to introduce digital signal modulation techniques and through the use of computer simulation, generate statistics which represent the characteristics of the FFT for the respective signal type. Further, an analysis of the statistics of the FFT's is conducted to determine if there is any relationship between the components of the FFT of the different signals. The statistic used to investigate this possible relationship is the F-distribution. The computer simulation is written and conducted in the FORTRAN programming language. A copy of the program, results of the simulation and the statistical analysis conducted are included in the appendices.

  1. Speech coding at 4800 bps for mobile satellite communications

    NASA Technical Reports Server (NTRS)

    Gersho, Allen; Chan, Wai-Yip; Davidson, Grant; Chen, Juin-Hwey; Yong, Mei

    1988-01-01

    A speech compression project has recently been completed to develop a speech coding algorithm suitable for operation in a mobile satellite environment aimed at providing telephone quality natural speech at 4.8 kbps. The work has resulted in two alternative techniques which achieve reasonably good communications quality at 4.8 kbps while tolerating vehicle noise and rather severe channel impairments. The algorithms are embodied in a compact self-contained prototype consisting of two AT and T 32-bit floating-point DSP32 digital signal processors (DSP). A Motorola 68HC11 microcomputer chip serves as the board controller and interface handler. On a wirewrapped card, the prototype's circuit footprint amounts to only 200 sq cm, and consumes about 9 watts of power.

  2. Experiments applications guide: Advanced Communications Technology Satellite (ACTS)

    NASA Technical Reports Server (NTRS)

    1988-01-01

    This applications guide first surveys the capabilities of the Advanced Communication Technology Satellite (ACTS) system (both the flight and ground segments). This overview is followed by a description of the baseband processor (BBP) and microwave switch matrix (MSM) operating modes. Terminals operating with the baseband processor are referred to as low burst rate (LBR); and those operating with the microwave switch matrix, as high burst rate (HBR). Three very small-aperture terminals (VSATs), LBR-1, LBR-2, and HBR, are described for various ACTS operating modes. Also described is the NASA Lewis link evaluation terminal. A section on ACTS experiment opportunities introduces a wide spectrum of network control, telecommunications, system, and scientific experiments. The performance of the VSATs is discussed in detail. This guide is intended as a catalyst to encourage participation by the telecommunications, business, and science communities in a broad spectrum of experiments.

  3. Baseband processor development for the Advanced Communications Satellite Program

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

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

  4. Considerations of digital phase modulation for narrowband satellite mobile communication

    NASA Technical Reports Server (NTRS)

    Grythe, Knut

    1990-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

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

  6. Coded octal phase shift keying in TDMA satellite communications

    NASA Astrophysics Data System (ADS)

    Rhodes, S. A.; Fang, R. J.; Chang, P. Y.

    The coded octal phase shift-keying (coded OPSK) signalling technique that has been proposed for TDMA satellite communications is presently subjected to a performance assessment for forward error correction (FEC) codes of different complexities. With the maximum likelihood path decoder, coded OPSK provides a coding gain relative to the performance of uncoded quaternary phase shift keying (QPSK). Significant coding gains of coded OPSK were obtained, relative to uncoded QPSK, for both an AWGN channel and a simulated INTELSAT V channel. Computer simulations have demonstrated that, for an FEC code of 64 states, coded OPSK transmitted over an AWGN channel yields a coding gain of about 3 dB and 4 dB at two different bit error probabilities. Corresponding coding gains for coded OPSK transmitted over the INTELSAT V channel were 3.2 dB and 4.5, at the same two bit error probability values.

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

    NASA Astrophysics Data System (ADS)

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

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

  8. 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.

  9. Adaptive beamforming in a CDMA mobile satellite communications system

    NASA Technical Reports Server (NTRS)

    Munoz-Garcia, Samuel G.

    1993-01-01

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

  10. Particle Filtering Equalization Method for a Satellite Communication Channel

    NASA Astrophysics Data System (ADS)

    Sénécal, Stéphane; Amblard, Pierre-Olivier; Cavazzana, Laurent

    2004-12-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

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

  12. 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

  13. Error control techniques for satellite and space communications

    NASA Technical Reports Server (NTRS)

    Costello, D. J., Jr.

    1986-01-01

    High rate concatenated coding systems with trellis inner codes and Reed-Solomon (RS) outer codes for application in satellite communication systems are considered. Two types of inner codes are studied: high rate punctured binary convolutional codes which result in overall effective information rates between 1/2 and 1 bit per channel use; and bandwidth efficient signal space trellis codes which can achieve overall effective information rates greater than 1 bit per channel use. Channel capacity calculations with and without side information performed for the concatenated coding system. Concatenated coding schemes are investigated. In Scheme 1, the inner code is decoded with the Viterbi algorithm and the outer RS code performs error-correction only (decoding without side information). In scheme 2, the inner code is decoded with a modified Viterbi algorithm which produces reliability information along with the decoded output. In this algorithm, path metrics are used to estimate the entire information sequence, while branch metrics are used to provide the reliability information on the decoded sequence. This information is used to erase unreliable bits in the decoded output. An errors-and-erasures RS decoder is then used for the outer code. These two schemes are proposed for use on NASA satellite channels. Results indicate that high system reliability can be achieved with little or no bandwidth expansion.

  14. 78 FR 31576 - Enforcement Proceeding; Certain Two-Way Global Satellite Communication Devices, System and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-24

    ... a complaint filed on behalf of BriarTek IP, Inc. (``BriarTek'') of Alexandria, Virginia. 77 FR 58579... COMMISSION Enforcement Proceeding; Certain Two-Way Global Satellite Communication Devices, System and... United States after importation of certain two-way global satellite communication devices, system...

  15. 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)

  16. 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…

  17. Communication Satellite Systems Conference, 10th, Orlando, FL, March 19-22, 1984, Technical Papers

    NASA Astrophysics Data System (ADS)

    Topics are discussed which are related to satellite communications in Latin America, the efficient use of the geostationary orbit, spacecraft antennas, direct broadcast systems, communication networks, earth stations, Ka-band systems and hardware, mobile systems, launch system developments, and satellite evaluation and test. Other subjects considered are concerned with Direct Broadcast Satellite (DBS) home terminals, regional and international systems, geostationary platforms and clusters, signal processing systems and technology, domestic systems, propagation effects, advanced spacecraft bus technology, military systems, systems availability and cost, and transponder components, taking into account low power devices and power amplifiers. Attention is given to a low cost communications satellite for developing countries, approaches for optimizing communications satellite reliability, and digital technologies and systems for geostationary orbit satellites. For individual items see A84-25252 to A84-25340

  18. Network design consideration of a satellite-based mobile communications system

    NASA Technical Reports Server (NTRS)

    Yan, T.-Y.

    1986-01-01

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

  19. 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.

  20. Economic benefits of the Space Station to commercial communication satellite operators

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

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

  1. An overview of the OmniTRACS: The first operational mobile Ku-band satellite communications

    NASA Technical Reports Server (NTRS)

    Salmasi, Allen

    1988-01-01

    The service features of the OmniTRACS system developed by Omninet Communications Services of Los Angeles, California are described. This system is the first operational mobile Ku-band satellite communications system that provides two-way messaging and position determination and reporting services to mobile users on a nationwide basis. The system uses existing Ku-band satellites under a secondary international allocation for mobile satellite services.

  2. Pegasus dedicated and multiple launch capabilities for low earth orbit communications satellite constellations

    NASA Astrophysics Data System (ADS)

    Mosier, Marty

    1992-03-01

    The design and standard payload interfaces of the Pegasus air-launched space booster are described and an overview of integration and launch operations is presented. Specific attention is given to services which are available to support multiple satellite launches. A recent multiple launch of seven small communication satellites is described which demonstrates Pegasus' capabilities to populate LEO communications satellite constellations quickly and cost effectively.

  3. Using satellite communications for a mobile computer network

    NASA Technical Reports Server (NTRS)

    Wyman, Douglas J.

    1993-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

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

  5. Faster than fiber: Advantages and challenges of LEO communications satellite systems

    NASA Astrophysics Data System (ADS)

    Campanella, S. Joseph; Kirkwood, Timothy J.

    1995-01-01

    Low Earth Orbit (LEO) communications satellite systems are emerging as attractive alternatives to the Geostationary Earth Orbit (GEO) systems. GEO satellites have largely dominated the commercial and government communications satellite systems for telecommunications services since the early 1960's. A principal driver behind the move to LEO satellites is the competition to long propagation delay geostationary orbit satellite systems created by rapid expansion of short propagation delay terrestrial land and undersea fiber optic cable links for national and global connectivity. Communication paths over LEO satellites can have shorter propagation delay than terrestrial fiber. This is because the speed of electromagnetic wave propagation via LEO satellites is 50% greater than that of light in fiber optic cable. This fact eliminates the long propagation delay property that has become synonymous with GEO communications satellite systems. Other drivers are the use of small portable and hand-held earth terminals and the promise of lower launch cost of small satellites to low earth orbits. The paper expands on the properties that promise to make LEO communications satellite systems the choice of the future.

  6. NASA's K/Ka-Band Broadband Aeronautical Terminal for Duplex Satellite Video Communications

    NASA Technical Reports Server (NTRS)

    Densmore, A.; Agan, M.

    1994-01-01

    JPL has recently begun the development of a Broadband Aeronautical Terminal (BAT) for duplex video satellite communications on commercial or business class aircraft. The BAT is designed for use with NASA's K/Ka-band Advanced Communications Technology Satellite (ACTS). The BAT system will provide the systems and technology groundwork for an eventual commercial K/Ka-band aeronautical satellite communication system. With industry/government partnerships, three main goals will be addressed by the BAT task: 1) develop, characterize and demonstrate the performance of an ACTS based high data rate aeronautical communications system; 2) assess the performance of current video compression algorithms in an aeronautical satellite communication link; and 3) characterize the propagation effects of the K/Ka-band channel for aeronautical communications.

  7. Communications to 2000 - A forecast of the demand and capacity of U.S. domestic communications satellites

    NASA Technical Reports Server (NTRS)

    Fordyce, S. W.

    1981-01-01

    The market demand for the U.S. domestic communications satellites accelerated in the late 70's, exceeding the capacity of the satellites currently in orbit. Satellite carriers have been authorized to build an additional 24 domsats. This paper examines the anticipated market demands, and the capability of the domsats to fulfill these demands. With various practical technical innovations, the domsats appear able to meet the expected market demands until the end of this century.

  8. Global disaster satellite communications system for disaster assessment and relief coordination

    NASA Technical Reports Server (NTRS)

    Leroy, B. E.

    1979-01-01

    The global communication requirements for disaster assistance and examines operationally feasible satellite system concepts and the associated system parameters are analyzed. Some potential problems associated with the current method of providing disaster assistance and a scenario for disaster assistance relying on satellite communications are described. Historical statistics are used with the scenario to assess service requirements. Both present and planned commercially available systems are considered. The associated global disaster communication yearly service costs are estimated.

  9. Role of Communications Satellites in the National and Global Information Infrastructure

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Early in 1995, the Satellite Industry Task Force (SITF) was initiated by executives of the satellite industry to define the role for communication satellites in the National and Global Information Infrastructure (NII/GII). Satellites are essential to this information network because they offer ubiquitous coverage and less time to market. SITF, which was chaired by Dr. Thomas Brackey of the Hughes Space and Communication Division, grew out of a series of workshops held during the summer of 1994 by the communication industry, NASA, and the Defense Information Systems Agency (DISA). Experts were convened from 20 companies representing satellite and terrestrial network builders, operators, and users. For 8 months they worked to identify challenges for the satellite industry to play a pivotal role in the National and Global Information Infrastructure. NASA Lewis Research Center personnel helped out with technical and policy matters.

  10. The use of satellites in non-geostationary orbits for unloading geostationary communication satellite traffic peaks. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    Price, K.; Turner, A.; Nguyen, T.; Doong, W.; Weyandt, C.

    1987-01-01

    The overall objective of this program was to assess the application, economic benefits, and technology and system implications of satellites in non-geostationary (non-GEO) orbits for off-loading peak traffic from GEO communications satellites. The study was organized into four technical tasks which are described in turn. They are: (1) concepts development; (2) system definition; (3) economic comparisons; and (4) technology requirements definition. Each of these tasks is defined in detail and the results of each are given.

  11. 77 FR 51045 - Certain Two-Way Global Satellite Communication Devices, System and Components Thereof; Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-23

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

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

    NASA Technical Reports Server (NTRS)

    Strauss, R.

    1993-01-01

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

  13. Prospects of satellite communications for mobiles: Towards a global mobile space segment

    NASA Astrophysics Data System (ADS)

    Rosetti, C.

    1981-11-01

    Terrestrial, maritime, and air transportation applications of communications satellites are considered. Communicating with long distance trucks can be achieved by text transmission which is cheaper than voice links, avoids access problems, and uses the frequency spectrum more efficiently. The need to accept fast and slow air traffic in the same air space, especially near airports, creates safety problems that can be overcome by equipping aircraft with a satellite controlled display device, showing traffic in the vicinity. The maritime satellite service is characterized by low market penetration that can be improved by cutting equipment costs, e.g., by decreasing ship antenna performance and using high gain satellite antennas, producing narrow beams.

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

    NASA Astrophysics Data System (ADS)

    Eun, Jong-Won

    2000-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

  16. 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.

  17. Sound broadcasting and newspaper page transmissions over satellite communication links

    NASA Astrophysics Data System (ADS)

    Kantor, L. Ia.; Chekhovskii, E. Y.

    1981-09-01

    Consideration is given to the use of satellite systems for newspaper facsimile transmission and sound broadcasting. Advantages of satellite transmission with respect to conventional terrestrial telephonic links for the transmission of centrally edited newspapers to decentralized printing houses are pointed out, and the systems established in the Soviet Union for newspaper transmission through satellite television systems along with television programs and digital sound broadcasting is indicated. The requirements of terrestrial and satellite links for sound program transmission are then compared and advantages of the satellite system with respect to the number of channels required, the possibility of decentralized control, and the independence of cost from distance are pointed out.

  18. Solid state laser communications in space (SOLACOS) high data rate satellite communication system verification program

    NASA Astrophysics Data System (ADS)

    Pribil, Klaus; Flemmig, Joerg

    1994-09-01

    This paper gives an overview on the current development status of the SOLACOS program and presents the highlights of the program. SOLACOS (Solid State Laser Communications in Space) is the national German program to develop a high performance laser communication system for high data rate transmission between LEO and GEO satellites (Inter Orbit Link, IOL). Two experimental demonstrator terminals are designed and developed in the SOLACOS program. The main development objectives are the Pointing Acquisition and Tracking subsystem (PAT) and the high data rate communication system. All key subsystems and components are straightway developed to be upgraded in follow- on projects to full space qualification. The main design objective for the system is a high degree of modularity which allows to easily upgrade the system with new upcoming technologies. Therefore, all main subsystems are interconnected via fibers to ease replacement of subsystems. The system implements an asymmetric data link with a 650 MBit/s return channel and a 10 MBit/s forward channel. The 650 MBit/s channel is based on a diode pumped Nd:YAG, Integrated Optics Modulator and uses the syncbit transmission scheme. In the syncbit system synchronization information which is necessary to maintain phase lock of the local oscillator of the coherent receiver is transmitted time multiplexed into the data stream. The PAT system comprises two beam detection sensors and three beam steering elements. For initial acquisition and tracking of the remote satellite a high speed CCD camera with an integrated image processing unit, the Acquisition and Tracking Sensor (ATS) is used. In the tacking mode the beam position is sensed via the Fibernutator sensor which is also used to couple the incoming signal into the receiver fiber. Incoming and outgoing beams are routed through the telescopes which are positioned with a 2 axis gimbal mechanism and a high speed beam steering mirror. The PAT system is controlled by a digital

  19. 42 CFR 52e.9 - Additional conditions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Additional conditions. 52e.9 Section 52e.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL HEART, LUNG, AND BLOOD INSTITUTE GRANTS FOR PREVENTION AND CONTROL PROJECTS § 52e.9 Additional conditions. The...

  20. 42 CFR 52e.9 - Additional conditions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Additional conditions. 52e.9 Section 52e.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL HEART, LUNG, AND BLOOD INSTITUTE GRANTS FOR PREVENTION AND CONTROL PROJECTS § 52e.9 Additional conditions. The...

  1. 42 CFR 52e.9 - Additional conditions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Additional conditions. 52e.9 Section 52e.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL HEART, LUNG, AND BLOOD INSTITUTE GRANTS FOR PREVENTION AND CONTROL PROJECTS § 52e.9 Additional conditions. The...

  2. 42 CFR 52e.9 - Additional conditions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Additional conditions. 52e.9 Section 52e.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL HEART, LUNG, AND BLOOD INSTITUTE GRANTS FOR PREVENTION AND CONTROL PROJECTS § 52e.9 Additional conditions. The...

  3. 42 CFR 52e.9 - Additional conditions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Additional conditions. 52e.9 Section 52e.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL HEART, LUNG, AND BLOOD INSTITUTE GRANTS FOR PREVENTION AND CONTROL PROJECTS § 52e.9 Additional conditions. The...

  4. Inter-satellite ranging and inter-satellite communication links for enhancing GNSS satellite broadcast navigation data

    NASA Astrophysics Data System (ADS)

    Fernández, Francisco Amarillo

    2011-03-01

    Recently the European Space Agency (ESA) has initiated a number of exploratory Projects, within the General Studies Programme (GSP), to analyze what potential improvements on a GNSS system navigation determination and dissemination performance could be brought by introducing inter-satellite ranging & inter-satellite communication-links. The key improvements targeted by these Projects are the enhancement of the orbit and clock prediction accuracy and the reduction of the dependency from ground infrastructure. Both projects adopted the Galileo system architecture as the initial working point.The first exploratory Project, which was labelled as GNSS+ (Amarillo and Gerner, 2007; Amarillo et al., 2008), indicated the practical difficulty to implement these new on-board functionalities except at the price of a visible increase of the payload mass and power (e.g. relative to mass and power of the Galileo IOV navigation payload) (Sánchez and Pulido, 2008); it allowed to define a preliminary system architecture, and it also allowed to identify the technological problems that in practise would likely be encountered.A second exploratory Project, which was labelled as ADVISE, continued the research, targeting a visible simplification of the GNSS+ architecture and an overall consolidation of the design of the most demanding constituents from technology perspective.This article describes the results of the GNSS+ Project as well as the improvements proposed in the frame of the ADVISE Project. As result of the ADVISE Project it has been possible to low very visibly the payload maximum RF power, and to keep the orbit and clock estimation accuracy, which was already on the few cm level.

  5. 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.

  6. 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.

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

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

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

  8. Sky-hooks, fish-warmers and hub-caps - Milestones in satellite communications

    NASA Astrophysics Data System (ADS)

    Rudge, A. W.

    1985-02-01

    The present discussion is concerned with the origin of satellite communications, its development and current status, and predictions regarding its future. The feasibility of such a communication system had been foreseen by Clarke (1945), who first recognized the peaceful potential of German rocketry, combined with the use of the geostationary orbit, as a basis for a worldwide communication system. After the launching of 'Sputnik', Clarke's concept of a 'sky-hook' was first implemented in 1964 with the experimental satellite Syncom. The founding of the International Telecommunications Satellite Organization (Intelsat) occurred in the same year. Attention is given to the various satellites of Intelsat with their increasing technological capabilities, the satellite industry in North America, developments in the USSR, the situation in the UK and in Western Europe, and advancements in spacecraft technology made by Japan, China, and the world at large. Details of spacecraft technology are considered along with ground stations.

  9. Coding for frequency hopped spread spectrum satellite communications

    NASA Astrophysics Data System (ADS)

    Bhargava, Vijay K.; Wang, Qiang; Blake, Ian F.; Li, Gang; Gulliver, T. Aaron; Dravnieks, Olaf

    1990-04-01

    Work aimed at improving the jamming resistance of satellite communications is reviewed. The performance of Reed-Solomon (RS) error correcting codes with slow frequency hopped (SFH) differential phase shift keying (DPSK) signalling is analyzed and evaluated under worst case partial band noise and worst case multitone jamming. A representative set of performance curves is shown. Recommendation on the choice of RS code parameters is given. Two in-hop jamming cancellation schemes for SFH/DPSK systems are proposed. One scheme is based on balanced coding; the other one uses notch filter to cancel jamming tone. The performance of both schemes is illustrated. It is shown that both schemes can work well under certain conditions. Basic principles and techniques for designing interleavers are presented. Block, convolution, and the more recent helical interleavers are considered. The trade-off between diversity and coding for spread spectrum systems, where a low code rate is anticipated, is discussed. An error correction scheme is presented for an M-ary symmetric channel (MSC) characterized by a large error probability (Pe). The value of Pe can be near, but smaller than 1-1/M, for which the channel capacity is zero. Such a large Pe may occur, for example, in a jamming environment. Monte-Carlo simulation results are presented. For the binary symmetric channel (BSC), it is shown that the overall code rate is larger than 0.6 R sub 0, where R sub 0 is the cutoff rate of the channel. For BSC and a large diversity order (m), a method is presented for BER (bit error rate) approximation on the central limit theorem.

  10. Integrated Cryogenic Satellite Communications Cross-Link Receiver Experiment

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Shamma, Mohammed A.

    2004-01-01

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

  13. Towards an empirical measure of spacecraft innovation: The case of communication satellites

    NASA Astrophysics Data System (ADS)

    Szajnfarber, Zoe; Weigel, Annalisa L.

    2010-04-01

    This paper seeks to frame the discussion of innovation in the space sector and creates a platform for future analysis. To accomplish this, it addressed three aspects of the task of measurement. First, it surveys several distinct literatures to establish precedence for defining a spacecraft innovation metric. Second, the conceptual trade-offs associated with adopting this principle in the context of communication satellites are elucidated and treated. By defining product boundaries along the dimensions of product scope and market transactions, three paradigms for measurement are proposed; namely: (1) the communication satellite enterprise; (2) the physical satellite; and (3) communication service. Third, under the constraints of historical data collection realities, next-best estimators are put forward as proxies for the parameters required to implement the proposed metrics. Based on these proxies, the relative merits of each measurement paradigm are illustrated through an analysis of the innovation history of communication satellites.

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

    ERIC Educational Resources Information Center

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

    1987-01-01

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

  15. Telemetry and telecommand requirements for future synchronous orbit communications satellites

    NASA Astrophysics Data System (ADS)

    Magnusson, Erland

    1989-01-01

    Requirements on telemetry and command are discussed from the satellite operations point of view. Requirements that lead to good visibility and control of the various satellite functions and enable the monitoring and control of the satellites to be computer-controlled are presented. Autonomous functions (on-board vs on-ground) are discussed, as are pros and cons on fixed and reconfigurable telemetry formats. The quantity and type of data required for computer-controlled satellite monitoring and control are discussed, as well as aspects on the use of spacecraft telemetry in systems testing of the spacecraft before launch.

  16. Satellite-aided land mobile communications system implementation considerations

    NASA Technical Reports Server (NTRS)

    Leroy, B. E.

    1982-01-01

    It was proposed that a satellite-based land mobile radio system could effectively extend the terrestrial cellular mobile system into rural and remote areas. The market, technical and economic feasibility for such a system is studied. Some of the aspects of implementing an operational mobile-satellite system are discussed. In particular, two key factors in implementation are examined: (1) bandwidth requirements; and (2) frequency sharing. Bandwidth requirements are derived based on the satellite antenna requirements, modulation characteristics and numbers of subscribers. Design trade-offs for the satellite system and potential implementation scenarios are identified. Frequency sharing is examined from a power flux density and modulation viewpoint.

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

    NASA Astrophysics Data System (ADS)

    Toyoshima, Morio; Takahashi, Takashi; Miura, Amane; Fujino, Yoshiyuki; Akioka, Maki

    2013-10-01

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

  18. The technical and economic considerations of bringing satellite communications to small mobile users

    NASA Astrophysics Data System (ADS)

    Anson, P.; Crompton, E. K.

    1984-05-01

    The potential market presented by small users is considered and the characteristics of the present systems of communication satellites are reviewed. The satellite parameters of antenna gain and directivity and of bandwidth are then discussed and the operational considerations of the existing satellites are examined with reference to the requirements of the proposed small mobile users. The implications of economic tariffs are briefly touched upon.

  19. Remarks by Dr. James C. Fletcher at Conference on Satellite Communication and Public Service

    NASA Technical Reports Server (NTRS)

    Fletcher, J. C.

    1976-01-01

    The present status of communications satellites, together with the future goals and technology developments in use of public service, is assessed. Improvements in design during the last decade considerably cut the cost of their development and launching, and the systems carry information to millions of people on earth. The space shuttles will change the rules in design and make it possible for communications satellites to have multiple frequencies operating at high power.

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

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

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

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

    ERIC Educational Resources Information Center

    Morgan, Robert P.; Singh, Jai P.

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

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

    ERIC Educational Resources Information Center

    Polcyn, Kenneth A.

    1981-01-01

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

  3. Communications Satellites in Health Education and Health Care Delivery: Operation Considerations.

    ERIC Educational Resources Information Center

    Boor, John L.; And Others

    1980-01-01

    Reviews user-related pitfalls which occurred during 222 satellite-mediated broadcasts which were related to medical education and health care delivery, and directed to Washington, Alaska, Montana, and Idaho. Specific consideration is given to those problems which need to be remedied for a user-acceptable system of satellite communication. (FM)

  4. The National Institute of Education's Educational Satellite Communications Demonstration: Lessons Learned and Their Federal Policy Implications.

    ERIC Educational Resources Information Center

    Porter, Steven

    During 1975, the Educational Satellite Communications Demonstration (ESCD) used the Applications Technology Satellite #6 (ATS-6) for three distinct demonstrations in Appalachia, Alaska, and the Rocky Mountain area. The most common use of the technology was to broadcast an uninterrupted program followed by a short interaction period. Other…

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

    ERIC Educational Resources Information Center

    Practical Concepts, Inc., Washington, DC.

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

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

    NASA Astrophysics Data System (ADS)

    Freidell, James E.

    1997-04-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

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

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

    ERIC Educational Resources Information Center

    Texas Education Agency, Austin.

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

  9. PEACESAT [Pan Pacific Education and Communication Experiments by Satellite] Project Networks: Using Satellite Communication Networks to Improve Social Conditions. Report 3.

    ERIC Educational Resources Information Center

    Hawaii Univ., Honolulu.

    The PEACESAT Project (Pan-Pacific Education and Communication Experiments by Satellite) is an international educational experiment involving institutions in 12 nations of the Pacific basin. Begun in 1969 and in full operation since 1971, the network is designed to increase interaction among societies and to bring about social development. This…

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

    NASA Technical Reports Server (NTRS)

    Morgan, R. P.

    1975-01-01

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

  11. Study to forecast and determine characteristics of world satellite communications market

    NASA Technical Reports Server (NTRS)

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

    1983-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Cragg, Phil; Brockman, William E.

    2006-08-01

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

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

    NASA Technical Reports Server (NTRS)

    1977-01-01

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

  15. COMMUNICATION IN THE SPACE AGE, THE USE OF SATELLITES BY THE MASS MEDIA.

    ERIC Educational Resources Information Center

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

    THE FULL IMPACT OF SATELLITE COMMUNICATION WILL BE REALIZED ONLY WHEN IT BECOMES FEASIBLE TO SPACECAST DIRECTLY INTO HOMES, FACILITATING INEXPENSIVE LONG-DISTANCE CALLS AND ENABLING CONFERENCES TO BE HELD VIA TELEPHONE AND CLOSED-CIRCUIT TELEVISION. BUSINESS TRAVEL WILL DIMINISH. SPACE COMMUNICATION, BY INCREASING THE FLOW OF INFORMATION AND ITS…

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

    ERIC Educational Resources Information Center

    Gough, J. Eric; And Others

    1981-01-01

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

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

    ERIC Educational Resources Information Center

    White, Peter B.

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

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

    NASA Astrophysics Data System (ADS)

    Mirshams, Mehran; Zabihian, Ehsan; Zabihian, Ahmadreza

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

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  20. 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.